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Calculates the abundance difference for species between two samples. Differences are on abundance values provided, if relative data is used, then differences in relative abundance will be calculated. There are three ways differences can be calculated. 1) Between treatments within a block (note: block.var and treatment.var need to be specified). 2) Between treatments, pooling all replicates into a single species pool (note: pool = TRUE, treatment.var needs to be specified, and block.var = NULL). 3) All pairwise combinations between all replicates (note: block.var = NULL, pool = FALSE and specifying treatment.var is optional. If treatment.var is specified, the treatment that each replicate belongs to will also be listed in the output).

Usage

abundance_difference(
  df,
  time.var = NULL,
  species.var,
  abundance.var,
  replicate.var,
  treatment.var = NULL,
  pool = FALSE,
  block.var = NULL,
  reference.treatment = NULL
)

Arguments

df

A data frame containing a species, abundance, and replicate columns and optional time, treatment, and block columns.

time.var

The name of the optional time column.

species.var

The name of the species column.

abundance.var

The name of the abundance column.

replicate.var

The name of the replicate column. Replicate identifiers must be unique within the dataset and cannot be nested within treatments or blocks.

treatment.var

The name of the optional treatment column.

pool

An argument to allow abundance values to be pooled within a treatment. The default value is "FALSE", a value of "TRUE" averages abundance of each species within a treatment at a given time point.

block.var

The name of the optional block column.

reference.treatment

The name of the optional treatment that all other treatments will be compared to (e.g. only controls will be compared to all other treatments). If not specified all pairwise treatment comparisons will be made.

Value

The `abundance_difference()` function returns a data frame with a subset of the following columns: - **species.var**: A column that has same name and type as the `species.var` column. - **difference**: A numeric column of the abundance differences between the two samples being compared (replicates or treatments). A numeric column of the change in abundance between consecutive timepoints. A positive value occurs when a species has greater abundance in `replicate.var2` than in `replicate.var` and/or in `treatment.var2` than in `treatment.var`. - **replicate.var**: A column that has same name and type as the `replicate.var` column, represents the first replicate being compared. Note, a replicate column will be returned only when `pool = FALSE` or `block.var = NULL`. - **replicate.var2**: A column that has the same type as the `replicate.var` column, and is named `replicate.var` with a 2 appended to it, represents the second replicate being compared. Note, a `replicate.var` column will be returned only when `pool = FALSE` and `block.var = NULL`. - **time.var**: A column that has the same name and type as the `time.var` column, if `time.var` is specified. - **treatment.var**: A column that has same name and type as the `treatment.var` column, represents the first treatment being compared. A `treatment.var` column will be returned when `pool = TRUE`, `block.var` is specified, or `treatment.var` is specified. - **treatment.var2**: A column that has the same type as the `treatment.var` column, and is named `treatment.var` with a 2 appended to it, represents the second treatment being compared. A `treatment.var` column will be returned when `pool = TRUE`, `block.var` is specified, or `treatment.var` is specified. - **block.var**: A column that has same name and type as the `block.var` column, if `block.var` is specified.

References

Avolio et al. Submitted

Examples

data(pplots)
# With block and no time
df <- subset(pplots, year == 2002 & block < 3)
abundance_difference(df = df,
                     species.var = "species",
                     abundance.var = "relative_cover",
                     treatment.var = "treatment",
                     block.var = "block",
                     replicate.var = "plot")
#>     block plot plot2 treatment treatment2                    species
#> 2       1   25    29      N1P0       N2P0      ambrosia psilostachya
#> 3       1   29    13      N2P0       N2P3      ambrosia psilostachya
#> 4       1   25    13      N1P0       N2P3          amorpha canescens
#> 5       1   25    29      N1P0       N2P0          amorpha canescens
#> 6       1   29    13      N2P0       N2P3          amorpha canescens
#> 7       1   25    13      N1P0       N2P3        andropogon gerardii
#> 8       1   25    29      N1P0       N2P0        andropogon gerardii
#> 9       1   29    13      N2P0       N2P3        andropogon gerardii
#> 10      1   25    13      N1P0       N2P3       andropogon scoparius
#> 11      1   25    29      N1P0       N2P0       andropogon scoparius
#> 12      1   29    13      N2P0       N2P3       andropogon scoparius
#> 14      1   25    29      N1P0       N2P0     asclepias verticillata
#> 15      1   29    13      N2P0       N2P3     asclepias verticillata
#> 16      1   25    13      N1P0       N2P3            aster ericoides
#> 17      1   25    29      N1P0       N2P0            aster ericoides
#> 18      1   29    13      N2P0       N2P3            aster ericoides
#> 19      1   25    13      N1P0       N2P3             aster sericeus
#> 21      1   29    13      N2P0       N2P3             aster sericeus
#> 22      1   25    13      N1P0       N2P3     bouteloua curtipendula
#> 23      1   25    29      N1P0       N2P0     bouteloua curtipendula
#> 24      1   29    13      N2P0       N2P3     bouteloua curtipendula
#> 25      1   25    13      N1P0       N2P3           carex heliophila
#> 26      1   25    29      N1P0       N2P0           carex heliophila
#> 27      1   29    13      N2P0       N2P3           carex heliophila
#> 28      1   25    13      N1P0       N2P3               carex meadii
#> 29      1   25    29      N1P0       N2P0               carex meadii
#> 30      1   29    13      N2P0       N2P3               carex meadii
#> 31      1   25    13      N1P0       N2P3              dalea candida
#> 32      1   25    29      N1P0       N2P0              dalea candida
#> 33      1   29    13      N2P0       N2P3              dalea candida
#> 35      1   25    29      N1P0       N2P0             dalea purpurea
#> 36      1   29    13      N2P0       N2P3             dalea purpurea
#> 37      1   25    13      N1P0       N2P3 dichanthelium oligosanthes
#> 38      1   25    29      N1P0       N2P0 dichanthelium oligosanthes
#> 39      1   29    13      N2P0       N2P3 dichanthelium oligosanthes
#> 40      1   25    13      N1P0       N2P3     eragrostis spectabilis
#> 41      1   25    29      N1P0       N2P0     eragrostis spectabilis
#> 42      1   29    13      N2P0       N2P3     eragrostis spectabilis
#> 43      1   25    13      N1P0       N2P3          euphorbia serpens
#> 45      1   29    13      N2P0       N2P3          euphorbia serpens
#> 46      1   25    13      N1P0       N2P3        koeleria pyramidata
#> 47      1   25    29      N1P0       N2P0        koeleria pyramidata
#> 48      1   29    13      N2P0       N2P3        koeleria pyramidata
#> 49      1   25    13      N1P0       N2P3       kuhnia eupatorioides
#> 50      1   25    29      N1P0       N2P0       kuhnia eupatorioides
#> 52      1   25    13      N1P0       N2P3             linum sulcatum
#> 53      1   25    29      N1P0       N2P0             linum sulcatum
#> 54      1   29    13      N2P0       N2P3             linum sulcatum
#> 56      1   25    29      N1P0       N2P0     muhlenbergia cuspidata
#> 57      1   29    13      N2P0       N2P3     muhlenbergia cuspidata
#> 58      1   25    13      N1P0       N2P3            physalis pumila
#> 59      1   25    29      N1P0       N2P0            physalis pumila
#> 61      1   25    13      N1P0       N2P3              poa pratensis
#> 62      1   25    29      N1P0       N2P0              poa pratensis
#> 63      1   29    13      N2P0       N2P3              poa pratensis
#> 64      1   25    13      N1P0       N2P3        schrankia nuttallii
#> 66      1   29    13      N2P0       N2P3        schrankia nuttallii
#> 67      1   25    13      N1P0       N2P3         senecio plattensis
#> 68      1   25    29      N1P0       N2P0         senecio plattensis
#> 70      1   25    13      N1P0       N2P3     sisyrinchium campestre
#> 72      1   29    13      N2P0       N2P3     sisyrinchium campestre
#> 73      1   25    13      N1P0       N2P3     solidago missouriensis
#> 74      1   25    29      N1P0       N2P0     solidago missouriensis
#> 75      1   29    13      N2P0       N2P3     solidago missouriensis
#> 76      1   25    13      N1P0       N2P3         sorghastrum nutans
#> 77      1   25    29      N1P0       N2P0         sorghastrum nutans
#> 78      1   29    13      N2P0       N2P3         sorghastrum nutans
#> 79      1   25    13      N1P0       N2P3           sporobolus asper
#> 81      1   29    13      N2P0       N2P3           sporobolus asper
#> 82      1   25    13      N1P0       N2P3       triodanis perfoliata
#> 84      1   29    13      N2P0       N2P3       triodanis perfoliata
#> 85      2   27    21      N1P0       N2P3      ambrosia psilostachya
#> 86      2   27    32      N1P0       N2P0      ambrosia psilostachya
#> 87      2   32    21      N2P0       N2P3      ambrosia psilostachya
#> 88      2   27    21      N1P0       N2P3          amorpha canescens
#> 89      2   27    32      N1P0       N2P0          amorpha canescens
#> 90      2   32    21      N2P0       N2P3          amorpha canescens
#> 91      2   27    21      N1P0       N2P3        andropogon gerardii
#> 92      2   27    32      N1P0       N2P0        andropogon gerardii
#> 93      2   32    21      N2P0       N2P3        andropogon gerardii
#> 94      2   27    21      N1P0       N2P3       andropogon scoparius
#> 95      2   27    32      N1P0       N2P0       andropogon scoparius
#> 96      2   32    21      N2P0       N2P3       andropogon scoparius
#> 97      2   27    21      N1P0       N2P3        antennaria neglecta
#> 98      2   27    32      N1P0       N2P0        antennaria neglecta
#> 99      2   32    21      N2P0       N2P3        antennaria neglecta
#> 100     2   27    21      N1P0       N2P3     asclepias verticillata
#> 101     2   27    32      N1P0       N2P0     asclepias verticillata
#> 103     2   27    21      N1P0       N2P3            aster ericoides
#> 104     2   27    32      N1P0       N2P0            aster ericoides
#> 105     2   32    21      N2P0       N2P3            aster ericoides
#> 106     2   27    21      N1P0       N2P3     bouteloua curtipendula
#> 107     2   27    32      N1P0       N2P0     bouteloua curtipendula
#> 108     2   32    21      N2P0       N2P3     bouteloua curtipendula
#> 109     2   27    21      N1P0       N2P3              carex brevior
#> 111     2   32    21      N2P0       N2P3              carex brevior
#> 112     2   27    21      N1P0       N2P3           carex heliophila
#> 113     2   27    32      N1P0       N2P0           carex heliophila
#> 114     2   32    21      N2P0       N2P3           carex heliophila
#> 115     2   27    21      N1P0       N2P3               carex meadii
#> 116     2   27    32      N1P0       N2P0               carex meadii
#> 117     2   32    21      N2P0       N2P3               carex meadii
#> 118     2   27    21      N1P0       N2P3              dalea candida
#> 120     2   32    21      N2P0       N2P3              dalea candida
#> 122     2   27    32      N1P0       N2P0   dichanthelium acuminatum
#> 123     2   32    21      N2P0       N2P3   dichanthelium acuminatum
#> 124     2   27    21      N1P0       N2P3 dichanthelium oligosanthes
#> 125     2   27    32      N1P0       N2P0 dichanthelium oligosanthes
#> 126     2   32    21      N2P0       N2P3 dichanthelium oligosanthes
#> 127     2   27    21      N1P0       N2P3     eragrostis spectabilis
#> 128     2   27    32      N1P0       N2P0     eragrostis spectabilis
#> 129     2   32    21      N2P0       N2P3     eragrostis spectabilis
#> 130     2   27    21      N1P0       N2P3        koeleria pyramidata
#> 131     2   27    32      N1P0       N2P0        koeleria pyramidata
#> 134     2   27    32      N1P0       N2P0       kuhnia eupatorioides
#> 135     2   32    21      N2P0       N2P3       kuhnia eupatorioides
#> 136     2   27    21      N1P0       N2P3             linum sulcatum
#> 137     2   27    32      N1P0       N2P0             linum sulcatum
#> 138     2   32    21      N2P0       N2P3             linum sulcatum
#> 139     2   27    21      N1P0       N2P3            physalis pumila
#> 140     2   27    32      N1P0       N2P0            physalis pumila
#> 141     2   32    21      N2P0       N2P3            physalis pumila
#> 142     2   27    21      N1P0       N2P3              poa pratensis
#> 143     2   27    32      N1P0       N2P0              poa pratensis
#> 144     2   32    21      N2P0       N2P3              poa pratensis
#> 145     2   27    21      N1P0       N2P3            ruellia humilis
#> 146     2   27    32      N1P0       N2P0            ruellia humilis
#> 147     2   32    21      N2P0       N2P3            ruellia humilis
#> 149     2   27    32      N1P0       N2P0         senecio plattensis
#> 150     2   32    21      N2P0       N2P3         senecio plattensis
#> 151     2   27    21      N1P0       N2P3        solidago canadensis
#> 153     2   32    21      N2P0       N2P3        solidago canadensis
#> 154     2   27    21      N1P0       N2P3     solidago missouriensis
#> 155     2   27    32      N1P0       N2P0     solidago missouriensis
#> 156     2   32    21      N2P0       N2P3     solidago missouriensis
#> 157     2   27    21      N1P0       N2P3         sorghastrum nutans
#> 158     2   27    32      N1P0       N2P0         sorghastrum nutans
#> 159     2   32    21      N2P0       N2P3         sorghastrum nutans
#> 160     2   27    21      N1P0       N2P3           sporobolus asper
#> 161     2   27    32      N1P0       N2P0           sporobolus asper
#> 162     2   32    21      N2P0       N2P3           sporobolus asper
#>       difference
#> 2    0.009784736
#> 3   -0.009784736
#> 4    0.052532728
#> 5    0.011575488
#> 6    0.040957240
#> 7   -0.060255980
#> 8    0.015684662
#> 9   -0.075940642
#> 10  -0.029633737
#> 11  -0.021659375
#> 12  -0.007974362
#> 14   0.001956947
#> 15  -0.001956947
#> 16  -0.007357934
#> 17   0.017408936
#> 18  -0.024766870
#> 19   0.024291498
#> 21   0.024291498
#> 22   0.007108658
#> 23   0.010079732
#> 24  -0.002971074
#> 25   0.005677471
#> 26   0.034560269
#> 27  -0.028882798
#> 28  -0.021725677
#> 29  -0.024019345
#> 30   0.002293668
#> 31  -0.006369427
#> 32  -0.002455533
#> 33  -0.003913894
#> 35   0.001956947
#> 36  -0.001956947
#> 37   0.007405210
#> 38   0.006664423
#> 39   0.000740787
#> 40   0.005875172
#> 41  -0.004246285
#> 42   0.010121457
#> 43   0.002024291
#> 45   0.002024291
#> 46  -0.004345136
#> 47  -0.002455533
#> 48  -0.001889603
#> 49  -0.006369427
#> 50  -0.006369427
#> 52  -0.004246285
#> 53  -0.000332391
#> 54  -0.003913894
#> 56   0.005870841
#> 57  -0.005870841
#> 58  -0.004246285
#> 59  -0.004246285
#> 61  -0.056585609
#> 62  -0.016432539
#> 63  -0.040153070
#> 64   0.076923077
#> 66   0.076923077
#> 67  -0.002123142
#> 68  -0.002123142
#> 70   0.002024291
#> 72   0.002024291
#> 73  -0.003507053
#> 74  -0.022062398
#> 75   0.018555345
#> 76   0.010757540
#> 77  -0.009140730
#> 78   0.019898270
#> 79   0.010121457
#> 81   0.010121457
#> 82   0.002024291
#> 84   0.002024291
#> 85  -0.004474273
#> 86  -0.000671992
#> 87  -0.003802281
#> 88   0.046562410
#> 89   0.018339415
#> 90   0.028222995
#> 91  -0.310116353
#> 92  -0.147327770
#> 93  -0.162788583
#> 94   0.281782858
#> 95  -0.014970951
#> 96   0.296753809
#> 97   0.004784689
#> 98   0.002534854
#> 99   0.002249835
#> 100 -0.006711409
#> 101 -0.006711409
#> 103 -0.005469745
#> 104  0.045099991
#> 105 -0.050569736
#> 106  0.033471415
#> 107  0.083871352
#> 108 -0.050399937
#> 109  0.004784689
#> 111  0.004784689
#> 112  0.026760005
#> 113  0.017590867
#> 114  0.009169138
#> 115  0.008573906
#> 116  0.000144606
#> 117  0.008429300
#> 118  0.001594896
#> 120  0.001594896
#> 122  0.006337136
#> 123 -0.006337136
#> 124 -0.028793766
#> 125 -0.016859332
#> 126 -0.011934434
#> 127  0.019138756
#> 128  0.003802281
#> 129  0.015336475
#> 130 -0.004474273
#> 131 -0.004474273
#> 134  0.006337136
#> 135 -0.006337136
#> 136  0.000952657
#> 137  0.001565145
#> 138 -0.000612488
#> 139 -0.005116513
#> 140 -0.006711409
#> 141  0.001594896
#> 142  0.003810625
#> 143  0.004993152
#> 144 -0.001182527
#> 145 -0.000642240
#> 146  0.005367427
#> 147 -0.006009667
#> 149  0.001267427
#> 150 -0.001267427
#> 151  0.001594896
#> 153  0.001594896
#> 154 -0.035794183
#> 155 -0.023119912
#> 156 -0.012674271
#> 157 -0.025507638
#> 158  0.003691700
#> 159 -0.029199338
#> 160 -0.006711409
#> 161  0.019904561
#> 162 -0.026615970

# With blocks and time
df <- subset(pplots, year < 2004 & block < 3)
abundance_difference(df = df,
                     species.var = "species",
                     abundance.var = "relative_cover",
                     treatment.var = "treatment",
                     block.var = "block",
                     replicate.var = "plot",
                     time.var = "year")
#>     year block plot plot2 treatment treatment2                    species
#> 2   2002     1   25    29      N1P0       N2P0      ambrosia psilostachya
#> 3   2002     1   29    13      N2P0       N2P3      ambrosia psilostachya
#> 4   2002     1   25    13      N1P0       N2P3          amorpha canescens
#> 5   2002     1   25    29      N1P0       N2P0          amorpha canescens
#> 6   2002     1   29    13      N2P0       N2P3          amorpha canescens
#> 7   2002     1   25    13      N1P0       N2P3        andropogon gerardii
#> 8   2002     1   25    29      N1P0       N2P0        andropogon gerardii
#> 9   2002     1   29    13      N2P0       N2P3        andropogon gerardii
#> 10  2002     1   25    13      N1P0       N2P3       andropogon scoparius
#> 11  2002     1   25    29      N1P0       N2P0       andropogon scoparius
#> 12  2002     1   29    13      N2P0       N2P3       andropogon scoparius
#> 14  2002     1   25    29      N1P0       N2P0     asclepias verticillata
#> 15  2002     1   29    13      N2P0       N2P3     asclepias verticillata
#> 16  2002     1   25    13      N1P0       N2P3            aster ericoides
#> 17  2002     1   25    29      N1P0       N2P0            aster ericoides
#> 18  2002     1   29    13      N2P0       N2P3            aster ericoides
#> 19  2002     1   25    13      N1P0       N2P3             aster sericeus
#> 21  2002     1   29    13      N2P0       N2P3             aster sericeus
#> 22  2002     1   25    13      N1P0       N2P3     bouteloua curtipendula
#> 23  2002     1   25    29      N1P0       N2P0     bouteloua curtipendula
#> 24  2002     1   29    13      N2P0       N2P3     bouteloua curtipendula
#> 25  2002     1   25    13      N1P0       N2P3           carex heliophila
#> 26  2002     1   25    29      N1P0       N2P0           carex heliophila
#> 27  2002     1   29    13      N2P0       N2P3           carex heliophila
#> 28  2002     1   25    13      N1P0       N2P3               carex meadii
#> 29  2002     1   25    29      N1P0       N2P0               carex meadii
#> 30  2002     1   29    13      N2P0       N2P3               carex meadii
#> 31  2002     1   25    13      N1P0       N2P3              dalea candida
#> 32  2002     1   25    29      N1P0       N2P0              dalea candida
#> 33  2002     1   29    13      N2P0       N2P3              dalea candida
#> 35  2002     1   25    29      N1P0       N2P0             dalea purpurea
#> 36  2002     1   29    13      N2P0       N2P3             dalea purpurea
#> 37  2002     1   25    13      N1P0       N2P3 dichanthelium oligosanthes
#> 38  2002     1   25    29      N1P0       N2P0 dichanthelium oligosanthes
#> 39  2002     1   29    13      N2P0       N2P3 dichanthelium oligosanthes
#> 40  2002     1   25    13      N1P0       N2P3     eragrostis spectabilis
#> 41  2002     1   25    29      N1P0       N2P0     eragrostis spectabilis
#> 42  2002     1   29    13      N2P0       N2P3     eragrostis spectabilis
#> 43  2002     1   25    13      N1P0       N2P3          euphorbia serpens
#> 45  2002     1   29    13      N2P0       N2P3          euphorbia serpens
#> 46  2002     1   25    13      N1P0       N2P3        koeleria pyramidata
#> 47  2002     1   25    29      N1P0       N2P0        koeleria pyramidata
#> 48  2002     1   29    13      N2P0       N2P3        koeleria pyramidata
#> 49  2002     1   25    13      N1P0       N2P3       kuhnia eupatorioides
#> 50  2002     1   25    29      N1P0       N2P0       kuhnia eupatorioides
#> 52  2002     1   25    13      N1P0       N2P3             linum sulcatum
#> 53  2002     1   25    29      N1P0       N2P0             linum sulcatum
#> 54  2002     1   29    13      N2P0       N2P3             linum sulcatum
#> 56  2002     1   25    29      N1P0       N2P0     muhlenbergia cuspidata
#> 57  2002     1   29    13      N2P0       N2P3     muhlenbergia cuspidata
#> 58  2002     1   25    13      N1P0       N2P3            physalis pumila
#> 59  2002     1   25    29      N1P0       N2P0            physalis pumila
#> 61  2002     1   25    13      N1P0       N2P3              poa pratensis
#> 62  2002     1   25    29      N1P0       N2P0              poa pratensis
#> 63  2002     1   29    13      N2P0       N2P3              poa pratensis
#> 64  2002     1   25    13      N1P0       N2P3        schrankia nuttallii
#> 66  2002     1   29    13      N2P0       N2P3        schrankia nuttallii
#> 67  2002     1   25    13      N1P0       N2P3         senecio plattensis
#> 68  2002     1   25    29      N1P0       N2P0         senecio plattensis
#> 70  2002     1   25    13      N1P0       N2P3     sisyrinchium campestre
#> 72  2002     1   29    13      N2P0       N2P3     sisyrinchium campestre
#> 73  2002     1   25    13      N1P0       N2P3     solidago missouriensis
#> 74  2002     1   25    29      N1P0       N2P0     solidago missouriensis
#> 75  2002     1   29    13      N2P0       N2P3     solidago missouriensis
#> 76  2002     1   25    13      N1P0       N2P3         sorghastrum nutans
#> 77  2002     1   25    29      N1P0       N2P0         sorghastrum nutans
#> 78  2002     1   29    13      N2P0       N2P3         sorghastrum nutans
#> 79  2002     1   25    13      N1P0       N2P3           sporobolus asper
#> 81  2002     1   29    13      N2P0       N2P3           sporobolus asper
#> 82  2002     1   25    13      N1P0       N2P3       triodanis perfoliata
#> 84  2002     1   29    13      N2P0       N2P3       triodanis perfoliata
#> 85  2002     2   27    21      N1P0       N2P3      ambrosia psilostachya
#> 86  2002     2   27    32      N1P0       N2P0      ambrosia psilostachya
#> 87  2002     2   32    21      N2P0       N2P3      ambrosia psilostachya
#> 88  2002     2   27    21      N1P0       N2P3          amorpha canescens
#> 89  2002     2   27    32      N1P0       N2P0          amorpha canescens
#> 90  2002     2   32    21      N2P0       N2P3          amorpha canescens
#> 91  2002     2   27    21      N1P0       N2P3        andropogon gerardii
#> 92  2002     2   27    32      N1P0       N2P0        andropogon gerardii
#> 93  2002     2   32    21      N2P0       N2P3        andropogon gerardii
#> 94  2002     2   27    21      N1P0       N2P3       andropogon scoparius
#> 95  2002     2   27    32      N1P0       N2P0       andropogon scoparius
#> 96  2002     2   32    21      N2P0       N2P3       andropogon scoparius
#> 97  2002     2   27    21      N1P0       N2P3        antennaria neglecta
#> 98  2002     2   27    32      N1P0       N2P0        antennaria neglecta
#> 99  2002     2   32    21      N2P0       N2P3        antennaria neglecta
#> 100 2002     2   27    21      N1P0       N2P3     asclepias verticillata
#> 101 2002     2   27    32      N1P0       N2P0     asclepias verticillata
#> 103 2002     2   27    21      N1P0       N2P3            aster ericoides
#> 104 2002     2   27    32      N1P0       N2P0            aster ericoides
#> 105 2002     2   32    21      N2P0       N2P3            aster ericoides
#> 106 2002     2   27    21      N1P0       N2P3     bouteloua curtipendula
#> 107 2002     2   27    32      N1P0       N2P0     bouteloua curtipendula
#> 108 2002     2   32    21      N2P0       N2P3     bouteloua curtipendula
#> 109 2002     2   27    21      N1P0       N2P3              carex brevior
#> 111 2002     2   32    21      N2P0       N2P3              carex brevior
#> 112 2002     2   27    21      N1P0       N2P3           carex heliophila
#> 113 2002     2   27    32      N1P0       N2P0           carex heliophila
#> 114 2002     2   32    21      N2P0       N2P3           carex heliophila
#> 115 2002     2   27    21      N1P0       N2P3               carex meadii
#> 116 2002     2   27    32      N1P0       N2P0               carex meadii
#> 117 2002     2   32    21      N2P0       N2P3               carex meadii
#> 118 2002     2   27    21      N1P0       N2P3              dalea candida
#> 120 2002     2   32    21      N2P0       N2P3              dalea candida
#> 122 2002     2   27    32      N1P0       N2P0   dichanthelium acuminatum
#> 123 2002     2   32    21      N2P0       N2P3   dichanthelium acuminatum
#> 124 2002     2   27    21      N1P0       N2P3 dichanthelium oligosanthes
#> 125 2002     2   27    32      N1P0       N2P0 dichanthelium oligosanthes
#> 126 2002     2   32    21      N2P0       N2P3 dichanthelium oligosanthes
#> 127 2002     2   27    21      N1P0       N2P3     eragrostis spectabilis
#> 128 2002     2   27    32      N1P0       N2P0     eragrostis spectabilis
#> 129 2002     2   32    21      N2P0       N2P3     eragrostis spectabilis
#> 130 2002     2   27    21      N1P0       N2P3        koeleria pyramidata
#> 131 2002     2   27    32      N1P0       N2P0        koeleria pyramidata
#> 134 2002     2   27    32      N1P0       N2P0       kuhnia eupatorioides
#> 135 2002     2   32    21      N2P0       N2P3       kuhnia eupatorioides
#> 136 2002     2   27    21      N1P0       N2P3             linum sulcatum
#> 137 2002     2   27    32      N1P0       N2P0             linum sulcatum
#> 138 2002     2   32    21      N2P0       N2P3             linum sulcatum
#> 139 2002     2   27    21      N1P0       N2P3            physalis pumila
#> 140 2002     2   27    32      N1P0       N2P0            physalis pumila
#> 141 2002     2   32    21      N2P0       N2P3            physalis pumila
#> 142 2002     2   27    21      N1P0       N2P3              poa pratensis
#> 143 2002     2   27    32      N1P0       N2P0              poa pratensis
#> 144 2002     2   32    21      N2P0       N2P3              poa pratensis
#> 145 2002     2   27    21      N1P0       N2P3            ruellia humilis
#> 146 2002     2   27    32      N1P0       N2P0            ruellia humilis
#> 147 2002     2   32    21      N2P0       N2P3            ruellia humilis
#> 149 2002     2   27    32      N1P0       N2P0         senecio plattensis
#> 150 2002     2   32    21      N2P0       N2P3         senecio plattensis
#> 151 2002     2   27    21      N1P0       N2P3        solidago canadensis
#> 153 2002     2   32    21      N2P0       N2P3        solidago canadensis
#> 154 2002     2   27    21      N1P0       N2P3     solidago missouriensis
#> 155 2002     2   27    32      N1P0       N2P0     solidago missouriensis
#> 156 2002     2   32    21      N2P0       N2P3     solidago missouriensis
#> 157 2002     2   27    21      N1P0       N2P3         sorghastrum nutans
#> 158 2002     2   27    32      N1P0       N2P0         sorghastrum nutans
#> 159 2002     2   32    21      N2P0       N2P3         sorghastrum nutans
#> 160 2002     2   27    21      N1P0       N2P3           sporobolus asper
#> 161 2002     2   27    32      N1P0       N2P0           sporobolus asper
#> 162 2002     2   32    21      N2P0       N2P3           sporobolus asper
#> 164 2003     1   25    29      N1P0       N2P0      ambrosia psilostachya
#> 165 2003     1   29    13      N2P0       N2P3      ambrosia psilostachya
#> 166 2003     1   25    13      N1P0       N2P3          amorpha canescens
#> 167 2003     1   25    29      N1P0       N2P0          amorpha canescens
#> 168 2003     1   29    13      N2P0       N2P3          amorpha canescens
#> 169 2003     1   25    13      N1P0       N2P3        andropogon gerardii
#> 170 2003     1   25    29      N1P0       N2P0        andropogon gerardii
#> 171 2003     1   29    13      N2P0       N2P3        andropogon gerardii
#> 172 2003     1   25    13      N1P0       N2P3       andropogon scoparius
#> 173 2003     1   25    29      N1P0       N2P0       andropogon scoparius
#> 174 2003     1   29    13      N2P0       N2P3       andropogon scoparius
#> 176 2003     1   25    29      N1P0       N2P0     asclepias verticillata
#> 177 2003     1   29    13      N2P0       N2P3     asclepias verticillata
#> 178 2003     1   25    13      N1P0       N2P3            aster ericoides
#> 179 2003     1   25    29      N1P0       N2P0            aster ericoides
#> 180 2003     1   29    13      N2P0       N2P3            aster ericoides
#> 181 2003     1   25    13      N1P0       N2P3             aster sericeus
#> 183 2003     1   29    13      N2P0       N2P3             aster sericeus
#> 184 2003     1   25    13      N1P0       N2P3     bouteloua curtipendula
#> 185 2003     1   25    29      N1P0       N2P0     bouteloua curtipendula
#> 186 2003     1   29    13      N2P0       N2P3     bouteloua curtipendula
#> 188 2003     1   25    29      N1P0       N2P0         bouteloua gracilis
#> 189 2003     1   29    13      N2P0       N2P3         bouteloua gracilis
#> 190 2003     1   25    13      N1P0       N2P3           carex heliophila
#> 191 2003     1   25    29      N1P0       N2P0           carex heliophila
#> 192 2003     1   29    13      N2P0       N2P3           carex heliophila
#> 193 2003     1   25    13      N1P0       N2P3               carex meadii
#> 194 2003     1   25    29      N1P0       N2P0               carex meadii
#> 195 2003     1   29    13      N2P0       N2P3               carex meadii
#> 196 2003     1   25    13      N1P0       N2P3              dalea candida
#> 197 2003     1   25    29      N1P0       N2P0              dalea candida
#> 198 2003     1   29    13      N2P0       N2P3              dalea candida
#> 199 2003     1   25    13      N1P0       N2P3             dalea purpurea
#> 200 2003     1   25    29      N1P0       N2P0             dalea purpurea
#> 201 2003     1   29    13      N2P0       N2P3             dalea purpurea
#> 202 2003     1   25    13      N1P0       N2P3   dichanthelium acuminatum
#> 204 2003     1   29    13      N2P0       N2P3   dichanthelium acuminatum
#> 205 2003     1   25    13      N1P0       N2P3 dichanthelium oligosanthes
#> 206 2003     1   25    29      N1P0       N2P0 dichanthelium oligosanthes
#> 207 2003     1   29    13      N2P0       N2P3 dichanthelium oligosanthes
#> 208 2003     1   25    13      N1P0       N2P3     eragrostis spectabilis
#> 209 2003     1   25    29      N1P0       N2P0     eragrostis spectabilis
#> 210 2003     1   29    13      N2P0       N2P3     eragrostis spectabilis
#> 212 2003     1   25    29      N1P0       N2P0          euphorbia serpens
#> 213 2003     1   29    13      N2P0       N2P3          euphorbia serpens
#> 215 2003     1   25    29      N1P0       N2P0        koeleria pyramidata
#> 216 2003     1   29    13      N2P0       N2P3        koeleria pyramidata
#> 217 2003     1   25    13      N1P0       N2P3       kuhnia eupatorioides
#> 218 2003     1   25    29      N1P0       N2P0       kuhnia eupatorioides
#> 220 2003     1   25    13      N1P0       N2P3            physalis pumila
#> 221 2003     1   25    29      N1P0       N2P0            physalis pumila
#> 223 2003     1   25    13      N1P0       N2P3              poa pratensis
#> 224 2003     1   25    29      N1P0       N2P0              poa pratensis
#> 225 2003     1   29    13      N2P0       N2P3              poa pratensis
#> 226 2003     1   25    13      N1P0       N2P3        schrankia nuttallii
#> 228 2003     1   29    13      N2P0       N2P3        schrankia nuttallii
#> 229 2003     1   25    13      N1P0       N2P3     solidago missouriensis
#> 230 2003     1   25    29      N1P0       N2P0     solidago missouriensis
#> 231 2003     1   29    13      N2P0       N2P3     solidago missouriensis
#> 232 2003     1   25    13      N1P0       N2P3         sorghastrum nutans
#> 233 2003     1   25    29      N1P0       N2P0         sorghastrum nutans
#> 234 2003     1   29    13      N2P0       N2P3         sorghastrum nutans
#> 235 2003     1   25    13      N1P0       N2P3           sporobolus asper
#> 237 2003     1   29    13      N2P0       N2P3           sporobolus asper
#> 238 2003     1   25    13      N1P0       N2P3          viola rafinesquii
#> 239 2003     1   25    29      N1P0       N2P0          viola rafinesquii
#> 242 2003     2   27    32      N1P0       N2P0      ambrosia psilostachya
#> 243 2003     2   32    21      N2P0       N2P3      ambrosia psilostachya
#> 244 2003     2   27    21      N1P0       N2P3          amorpha canescens
#> 245 2003     2   27    32      N1P0       N2P0          amorpha canescens
#> 246 2003     2   32    21      N2P0       N2P3          amorpha canescens
#> 247 2003     2   27    21      N1P0       N2P3        andropogon gerardii
#> 248 2003     2   27    32      N1P0       N2P0        andropogon gerardii
#> 249 2003     2   32    21      N2P0       N2P3        andropogon gerardii
#> 250 2003     2   27    21      N1P0       N2P3       andropogon scoparius
#> 251 2003     2   27    32      N1P0       N2P0       andropogon scoparius
#> 252 2003     2   32    21      N2P0       N2P3       andropogon scoparius
#> 253 2003     2   27    21      N1P0       N2P3        antennaria neglecta
#> 255 2003     2   32    21      N2P0       N2P3        antennaria neglecta
#> 256 2003     2   27    21      N1P0       N2P3      asclepias stenophylla
#> 257 2003     2   27    32      N1P0       N2P0      asclepias stenophylla
#> 259 2003     2   27    21      N1P0       N2P3         asclepias tuberosa
#> 260 2003     2   27    32      N1P0       N2P0         asclepias tuberosa
#> 261 2003     2   32    21      N2P0       N2P3         asclepias tuberosa
#> 262 2003     2   27    21      N1P0       N2P3     asclepias verticillata
#> 263 2003     2   27    32      N1P0       N2P0     asclepias verticillata
#> 265 2003     2   27    21      N1P0       N2P3            aster ericoides
#> 266 2003     2   27    32      N1P0       N2P0            aster ericoides
#> 267 2003     2   32    21      N2P0       N2P3            aster ericoides
#> 269 2003     2   27    32      N1P0       N2P0        aster oblongifolius
#> 270 2003     2   32    21      N2P0       N2P3        aster oblongifolius
#> 271 2003     2   27    21      N1P0       N2P3     bouteloua curtipendula
#> 272 2003     2   27    32      N1P0       N2P0     bouteloua curtipendula
#> 273 2003     2   32    21      N2P0       N2P3     bouteloua curtipendula
#> 274 2003     2   27    21      N1P0       N2P3           carex heliophila
#> 275 2003     2   27    32      N1P0       N2P0           carex heliophila
#> 276 2003     2   32    21      N2P0       N2P3           carex heliophila
#> 277 2003     2   27    21      N1P0       N2P3               carex meadii
#> 278 2003     2   27    32      N1P0       N2P0               carex meadii
#> 279 2003     2   32    21      N2P0       N2P3               carex meadii
#> 280 2003     2   27    21      N1P0       N2P3              dalea candida
#> 282 2003     2   32    21      N2P0       N2P3              dalea candida
#> 284 2003     2   27    32      N1P0       N2P0       delphinium virescens
#> 285 2003     2   32    21      N2P0       N2P3       delphinium virescens
#> 286 2003     2   27    21      N1P0       N2P3 dichanthelium oligosanthes
#> 287 2003     2   27    32      N1P0       N2P0 dichanthelium oligosanthes
#> 288 2003     2   32    21      N2P0       N2P3 dichanthelium oligosanthes
#> 289 2003     2   27    21      N1P0       N2P3     eragrostis spectabilis
#> 291 2003     2   32    21      N2P0       N2P3     eragrostis spectabilis
#> 293 2003     2   27    32      N1P0       N2P0          euphorbia serpens
#> 294 2003     2   32    21      N2P0       N2P3          euphorbia serpens
#> 295 2003     2   27    21      N1P0       N2P3        koeleria pyramidata
#> 296 2003     2   27    32      N1P0       N2P0        koeleria pyramidata
#> 299 2003     2   27    32      N1P0       N2P0       kuhnia eupatorioides
#> 300 2003     2   32    21      N2P0       N2P3       kuhnia eupatorioides
#> 301 2003     2   27    21      N1P0       N2P3             linum sulcatum
#> 302 2003     2   27    32      N1P0       N2P0             linum sulcatum
#> 305 2003     2   27    32      N1P0       N2P0          panicum capillare
#> 306 2003     2   32    21      N2P0       N2P3          panicum capillare
#> 307 2003     2   27    21      N1P0       N2P3            physalis pumila
#> 308 2003     2   27    32      N1P0       N2P0            physalis pumila
#> 309 2003     2   32    21      N2P0       N2P3            physalis pumila
#> 310 2003     2   27    21      N1P0       N2P3              poa pratensis
#> 311 2003     2   27    32      N1P0       N2P0              poa pratensis
#> 312 2003     2   32    21      N2P0       N2P3              poa pratensis
#> 313 2003     2   27    21      N1P0       N2P3            ruellia humilis
#> 314 2003     2   27    32      N1P0       N2P0            ruellia humilis
#> 315 2003     2   32    21      N2P0       N2P3            ruellia humilis
#> 317 2003     2   27    32      N1P0       N2P0         senecio plattensis
#> 318 2003     2   32    21      N2P0       N2P3         senecio plattensis
#> 319 2003     2   27    21      N1P0       N2P3        solidago canadensis
#> 321 2003     2   32    21      N2P0       N2P3        solidago canadensis
#> 322 2003     2   27    21      N1P0       N2P3     solidago missouriensis
#> 323 2003     2   27    32      N1P0       N2P0     solidago missouriensis
#> 324 2003     2   32    21      N2P0       N2P3     solidago missouriensis
#> 325 2003     2   27    21      N1P0       N2P3         sorghastrum nutans
#> 326 2003     2   27    32      N1P0       N2P0         sorghastrum nutans
#> 327 2003     2   32    21      N2P0       N2P3         sorghastrum nutans
#> 328 2003     2   27    21      N1P0       N2P3           sporobolus asper
#> 329 2003     2   27    32      N1P0       N2P0           sporobolus asper
#> 330 2003     2   32    21      N2P0       N2P3           sporobolus asper
#> 331 2003     2   27    21      N1P0       N2P3           viola pedatifida
#> 333 2003     2   32    21      N2P0       N2P3           viola pedatifida
#>       difference
#> 2    0.009784736
#> 3   -0.009784736
#> 4    0.052532728
#> 5    0.011575488
#> 6    0.040957240
#> 7   -0.060255980
#> 8    0.015684662
#> 9   -0.075940642
#> 10  -0.029633737
#> 11  -0.021659375
#> 12  -0.007974362
#> 14   0.001956947
#> 15  -0.001956947
#> 16  -0.007357934
#> 17   0.017408936
#> 18  -0.024766870
#> 19   0.024291498
#> 21   0.024291498
#> 22   0.007108658
#> 23   0.010079732
#> 24  -0.002971074
#> 25   0.005677471
#> 26   0.034560269
#> 27  -0.028882798
#> 28  -0.021725677
#> 29  -0.024019345
#> 30   0.002293668
#> 31  -0.006369427
#> 32  -0.002455533
#> 33  -0.003913894
#> 35   0.001956947
#> 36  -0.001956947
#> 37   0.007405210
#> 38   0.006664423
#> 39   0.000740787
#> 40   0.005875172
#> 41  -0.004246285
#> 42   0.010121457
#> 43   0.002024291
#> 45   0.002024291
#> 46  -0.004345136
#> 47  -0.002455533
#> 48  -0.001889603
#> 49  -0.006369427
#> 50  -0.006369427
#> 52  -0.004246285
#> 53  -0.000332391
#> 54  -0.003913894
#> 56   0.005870841
#> 57  -0.005870841
#> 58  -0.004246285
#> 59  -0.004246285
#> 61  -0.056585609
#> 62  -0.016432539
#> 63  -0.040153070
#> 64   0.076923077
#> 66   0.076923077
#> 67  -0.002123142
#> 68  -0.002123142
#> 70   0.002024291
#> 72   0.002024291
#> 73  -0.003507053
#> 74  -0.022062398
#> 75   0.018555345
#> 76   0.010757540
#> 77  -0.009140730
#> 78   0.019898270
#> 79   0.010121457
#> 81   0.010121457
#> 82   0.002024291
#> 84   0.002024291
#> 85  -0.004474273
#> 86  -0.000671992
#> 87  -0.003802281
#> 88   0.046562410
#> 89   0.018339415
#> 90   0.028222995
#> 91  -0.310116353
#> 92  -0.147327770
#> 93  -0.162788583
#> 94   0.281782858
#> 95  -0.014970951
#> 96   0.296753809
#> 97   0.004784689
#> 98   0.002534854
#> 99   0.002249835
#> 100 -0.006711409
#> 101 -0.006711409
#> 103 -0.005469745
#> 104  0.045099991
#> 105 -0.050569736
#> 106  0.033471415
#> 107  0.083871352
#> 108 -0.050399937
#> 109  0.004784689
#> 111  0.004784689
#> 112  0.026760005
#> 113  0.017590867
#> 114  0.009169138
#> 115  0.008573906
#> 116  0.000144606
#> 117  0.008429300
#> 118  0.001594896
#> 120  0.001594896
#> 122  0.006337136
#> 123 -0.006337136
#> 124 -0.028793766
#> 125 -0.016859332
#> 126 -0.011934434
#> 127  0.019138756
#> 128  0.003802281
#> 129  0.015336475
#> 130 -0.004474273
#> 131 -0.004474273
#> 134  0.006337136
#> 135 -0.006337136
#> 136  0.000952657
#> 137  0.001565145
#> 138 -0.000612488
#> 139 -0.005116513
#> 140 -0.006711409
#> 141  0.001594896
#> 142  0.003810625
#> 143  0.004993152
#> 144 -0.001182527
#> 145 -0.000642240
#> 146  0.005367427
#> 147 -0.006009667
#> 149  0.001267427
#> 150 -0.001267427
#> 151  0.001594896
#> 153  0.001594896
#> 154 -0.035794183
#> 155 -0.023119912
#> 156 -0.012674271
#> 157 -0.025507638
#> 158  0.003691700
#> 159 -0.029199338
#> 160 -0.006711409
#> 161  0.019904561
#> 162 -0.026615970
#> 164  0.005468216
#> 165 -0.005468216
#> 166  0.100418410
#> 167  0.027341080
#> 168  0.073077330
#> 169  0.006551015
#> 170  0.020145290
#> 171 -0.013594275
#> 172 -0.033595076
#> 173 -0.079168309
#> 174  0.045573233
#> 176  0.001367054
#> 177 -0.001367054
#> 178  0.003752668
#> 179  0.068901276
#> 180 -0.065148608
#> 181  0.019525802
#> 183  0.019525802
#> 184  0.050085939
#> 185  0.050347147
#> 186 -0.000261208
#> 188  0.002734108
#> 189 -0.002734108
#> 190 -0.003563792
#> 191  0.012840856
#> 192 -0.016404648
#> 193 -0.010101883
#> 194 -0.012263049
#> 195  0.002161166
#> 196 -0.028510335
#> 197 -0.018940957
#> 198 -0.009569378
#> 199 -0.001425517
#> 200  0.005409753
#> 201 -0.006835270
#> 202  0.004184100
#> 204  0.004184100
#> 205 -0.000154083
#> 206  0.013378226
#> 207 -0.013532309
#> 208  0.027585837
#> 209 -0.014255167
#> 210  0.041841004
#> 212  0.006835270
#> 213 -0.006835270
#> 215  0.004101162
#> 216 -0.004101162
#> 217 -0.009978617
#> 218 -0.009978617
#> 220 -0.002851033
#> 221 -0.002851033
#> 223  0.006973501
#> 224  0.008202324
#> 225 -0.001228823
#> 226  0.069735007
#> 228  0.069735007
#> 229 -0.034212402
#> 230 -0.030111240
#> 231 -0.004101162
#> 232 -0.165783423
#> 233 -0.058077871
#> 234 -0.107705552
#> 235  0.002789400
#> 237  0.002789400
#> 238 -0.001425517
#> 239 -0.001425517
#> 242  0.002824859
#> 243 -0.002824859
#> 244  0.077244259
#> 245  0.028248588
#> 246  0.048995671
#> 247 -0.045922749
#> 248  0.174581361
#> 249 -0.220504110
#> 250  0.144695844
#> 251 -0.138647121
#> 252  0.283342965
#> 253  0.002087683
#> 255  0.002087683
#> 256 -0.001501502
#> 257 -0.001501502
#> 259 -0.001501502
#> 260  0.009797933
#> 261 -0.011299435
#> 262 -0.007507508
#> 263 -0.007507508
#> 265 -0.011754970
#> 266  0.027179722
#> 267 -0.038934692
#> 269  0.015065913
#> 270 -0.015065913
#> 271 -0.033763409
#> 272 -0.033720161
#> 273 -0.000043248
#> 274 -0.007507508
#> 275  0.031098895
#> 276 -0.038606403
#> 277  0.002180155
#> 278  0.052947015
#> 279 -0.050766860
#> 280  0.002087683
#> 282  0.002087683
#> 284  0.003766478
#> 285 -0.003766478
#> 286 -0.001861987
#> 287 -0.014506031
#> 288  0.012644044
#> 289  0.020876827
#> 291  0.020876827
#> 293  0.001883239
#> 294 -0.001883239
#> 295 -0.001501502
#> 296 -0.001501502
#> 299  0.009416196
#> 300 -0.009416196
#> 301 -0.003003003
#> 302 -0.003003003
#> 305  0.005649718
#> 306 -0.005649718
#> 307 -0.000915320
#> 308 -0.003003003
#> 309  0.002087683
#> 310  0.014613779
#> 311  0.005649718
#> 312  0.008964061
#> 313 -0.001501502
#> 314  0.007914694
#> 315 -0.009416196
#> 317  0.001883239
#> 318 -0.001883239
#> 319  0.002087683
#> 321  0.002087683
#> 322 -0.036786787
#> 323 -0.022662493
#> 324 -0.014124294
#> 325 -0.115020031
#> 326 -0.168804398
#> 327  0.053784367
#> 328  0.002087683
#> 329  0.016949153
#> 330 -0.014861470
#> 331  0.002087683
#> 333  0.002087683

# With blocks, time and reference treatment
df <- subset(pplots, year < 2004 & block < 3)
abundance_difference(df = df,
                     species.var = "species",
                     abundance.var = "relative_cover",
                     treatment.var = "treatment",
                     block.var = "block",
                     replicate.var = "plot",
                     time.var = "year",
                     reference.treatment = "N1P0")
#>     year block plot plot2 treatment treatment2                    species
#> 2   2002     1   25    29      N1P0       N2P0      ambrosia psilostachya
#> 3   2002     1   25    13      N1P0       N2P3          amorpha canescens
#> 4   2002     1   25    29      N1P0       N2P0          amorpha canescens
#> 5   2002     1   25    13      N1P0       N2P3        andropogon gerardii
#> 6   2002     1   25    29      N1P0       N2P0        andropogon gerardii
#> 7   2002     1   25    13      N1P0       N2P3       andropogon scoparius
#> 8   2002     1   25    29      N1P0       N2P0       andropogon scoparius
#> 10  2002     1   25    29      N1P0       N2P0     asclepias verticillata
#> 11  2002     1   25    13      N1P0       N2P3            aster ericoides
#> 12  2002     1   25    29      N1P0       N2P0            aster ericoides
#> 13  2002     1   25    13      N1P0       N2P3             aster sericeus
#> 15  2002     1   25    13      N1P0       N2P3     bouteloua curtipendula
#> 16  2002     1   25    29      N1P0       N2P0     bouteloua curtipendula
#> 17  2002     1   25    13      N1P0       N2P3           carex heliophila
#> 18  2002     1   25    29      N1P0       N2P0           carex heliophila
#> 19  2002     1   25    13      N1P0       N2P3               carex meadii
#> 20  2002     1   25    29      N1P0       N2P0               carex meadii
#> 21  2002     1   25    13      N1P0       N2P3              dalea candida
#> 22  2002     1   25    29      N1P0       N2P0              dalea candida
#> 24  2002     1   25    29      N1P0       N2P0             dalea purpurea
#> 25  2002     1   25    13      N1P0       N2P3 dichanthelium oligosanthes
#> 26  2002     1   25    29      N1P0       N2P0 dichanthelium oligosanthes
#> 27  2002     1   25    13      N1P0       N2P3     eragrostis spectabilis
#> 28  2002     1   25    29      N1P0       N2P0     eragrostis spectabilis
#> 29  2002     1   25    13      N1P0       N2P3          euphorbia serpens
#> 31  2002     1   25    13      N1P0       N2P3        koeleria pyramidata
#> 32  2002     1   25    29      N1P0       N2P0        koeleria pyramidata
#> 33  2002     1   25    13      N1P0       N2P3       kuhnia eupatorioides
#> 34  2002     1   25    29      N1P0       N2P0       kuhnia eupatorioides
#> 35  2002     1   25    13      N1P0       N2P3             linum sulcatum
#> 36  2002     1   25    29      N1P0       N2P0             linum sulcatum
#> 38  2002     1   25    29      N1P0       N2P0     muhlenbergia cuspidata
#> 39  2002     1   25    13      N1P0       N2P3            physalis pumila
#> 40  2002     1   25    29      N1P0       N2P0            physalis pumila
#> 41  2002     1   25    13      N1P0       N2P3              poa pratensis
#> 42  2002     1   25    29      N1P0       N2P0              poa pratensis
#> 43  2002     1   25    13      N1P0       N2P3        schrankia nuttallii
#> 45  2002     1   25    13      N1P0       N2P3         senecio plattensis
#> 46  2002     1   25    29      N1P0       N2P0         senecio plattensis
#> 47  2002     1   25    13      N1P0       N2P3     sisyrinchium campestre
#> 49  2002     1   25    13      N1P0       N2P3     solidago missouriensis
#> 50  2002     1   25    29      N1P0       N2P0     solidago missouriensis
#> 51  2002     1   25    13      N1P0       N2P3         sorghastrum nutans
#> 52  2002     1   25    29      N1P0       N2P0         sorghastrum nutans
#> 53  2002     1   25    13      N1P0       N2P3           sporobolus asper
#> 55  2002     1   25    13      N1P0       N2P3       triodanis perfoliata
#> 57  2002     2   27    21      N1P0       N2P3      ambrosia psilostachya
#> 58  2002     2   27    32      N1P0       N2P0      ambrosia psilostachya
#> 59  2002     2   27    21      N1P0       N2P3          amorpha canescens
#> 60  2002     2   27    32      N1P0       N2P0          amorpha canescens
#> 61  2002     2   27    21      N1P0       N2P3        andropogon gerardii
#> 62  2002     2   27    32      N1P0       N2P0        andropogon gerardii
#> 63  2002     2   27    21      N1P0       N2P3       andropogon scoparius
#> 64  2002     2   27    32      N1P0       N2P0       andropogon scoparius
#> 65  2002     2   27    21      N1P0       N2P3        antennaria neglecta
#> 66  2002     2   27    32      N1P0       N2P0        antennaria neglecta
#> 67  2002     2   27    21      N1P0       N2P3     asclepias verticillata
#> 68  2002     2   27    32      N1P0       N2P0     asclepias verticillata
#> 69  2002     2   27    21      N1P0       N2P3            aster ericoides
#> 70  2002     2   27    32      N1P0       N2P0            aster ericoides
#> 71  2002     2   27    21      N1P0       N2P3     bouteloua curtipendula
#> 72  2002     2   27    32      N1P0       N2P0     bouteloua curtipendula
#> 73  2002     2   27    21      N1P0       N2P3              carex brevior
#> 75  2002     2   27    21      N1P0       N2P3           carex heliophila
#> 76  2002     2   27    32      N1P0       N2P0           carex heliophila
#> 77  2002     2   27    21      N1P0       N2P3               carex meadii
#> 78  2002     2   27    32      N1P0       N2P0               carex meadii
#> 79  2002     2   27    21      N1P0       N2P3              dalea candida
#> 82  2002     2   27    32      N1P0       N2P0   dichanthelium acuminatum
#> 83  2002     2   27    21      N1P0       N2P3 dichanthelium oligosanthes
#> 84  2002     2   27    32      N1P0       N2P0 dichanthelium oligosanthes
#> 85  2002     2   27    21      N1P0       N2P3     eragrostis spectabilis
#> 86  2002     2   27    32      N1P0       N2P0     eragrostis spectabilis
#> 87  2002     2   27    21      N1P0       N2P3        koeleria pyramidata
#> 88  2002     2   27    32      N1P0       N2P0        koeleria pyramidata
#> 90  2002     2   27    32      N1P0       N2P0       kuhnia eupatorioides
#> 91  2002     2   27    21      N1P0       N2P3             linum sulcatum
#> 92  2002     2   27    32      N1P0       N2P0             linum sulcatum
#> 93  2002     2   27    21      N1P0       N2P3            physalis pumila
#> 94  2002     2   27    32      N1P0       N2P0            physalis pumila
#> 95  2002     2   27    21      N1P0       N2P3              poa pratensis
#> 96  2002     2   27    32      N1P0       N2P0              poa pratensis
#> 97  2002     2   27    21      N1P0       N2P3            ruellia humilis
#> 98  2002     2   27    32      N1P0       N2P0            ruellia humilis
#> 100 2002     2   27    32      N1P0       N2P0         senecio plattensis
#> 101 2002     2   27    21      N1P0       N2P3        solidago canadensis
#> 103 2002     2   27    21      N1P0       N2P3     solidago missouriensis
#> 104 2002     2   27    32      N1P0       N2P0     solidago missouriensis
#> 105 2002     2   27    21      N1P0       N2P3         sorghastrum nutans
#> 106 2002     2   27    32      N1P0       N2P0         sorghastrum nutans
#> 107 2002     2   27    21      N1P0       N2P3           sporobolus asper
#> 108 2002     2   27    32      N1P0       N2P0           sporobolus asper
#> 110 2003     1   25    29      N1P0       N2P0      ambrosia psilostachya
#> 111 2003     1   25    13      N1P0       N2P3          amorpha canescens
#> 112 2003     1   25    29      N1P0       N2P0          amorpha canescens
#> 113 2003     1   25    13      N1P0       N2P3        andropogon gerardii
#> 114 2003     1   25    29      N1P0       N2P0        andropogon gerardii
#> 115 2003     1   25    13      N1P0       N2P3       andropogon scoparius
#> 116 2003     1   25    29      N1P0       N2P0       andropogon scoparius
#> 118 2003     1   25    29      N1P0       N2P0     asclepias verticillata
#> 119 2003     1   25    13      N1P0       N2P3            aster ericoides
#> 120 2003     1   25    29      N1P0       N2P0            aster ericoides
#> 121 2003     1   25    13      N1P0       N2P3             aster sericeus
#> 123 2003     1   25    13      N1P0       N2P3     bouteloua curtipendula
#> 124 2003     1   25    29      N1P0       N2P0     bouteloua curtipendula
#> 126 2003     1   25    29      N1P0       N2P0         bouteloua gracilis
#> 127 2003     1   25    13      N1P0       N2P3           carex heliophila
#> 128 2003     1   25    29      N1P0       N2P0           carex heliophila
#> 129 2003     1   25    13      N1P0       N2P3               carex meadii
#> 130 2003     1   25    29      N1P0       N2P0               carex meadii
#> 131 2003     1   25    13      N1P0       N2P3              dalea candida
#> 132 2003     1   25    29      N1P0       N2P0              dalea candida
#> 133 2003     1   25    13      N1P0       N2P3             dalea purpurea
#> 134 2003     1   25    29      N1P0       N2P0             dalea purpurea
#> 135 2003     1   25    13      N1P0       N2P3   dichanthelium acuminatum
#> 137 2003     1   25    13      N1P0       N2P3 dichanthelium oligosanthes
#> 138 2003     1   25    29      N1P0       N2P0 dichanthelium oligosanthes
#> 139 2003     1   25    13      N1P0       N2P3     eragrostis spectabilis
#> 140 2003     1   25    29      N1P0       N2P0     eragrostis spectabilis
#> 142 2003     1   25    29      N1P0       N2P0          euphorbia serpens
#> 144 2003     1   25    29      N1P0       N2P0        koeleria pyramidata
#> 145 2003     1   25    13      N1P0       N2P3       kuhnia eupatorioides
#> 146 2003     1   25    29      N1P0       N2P0       kuhnia eupatorioides
#> 147 2003     1   25    13      N1P0       N2P3            physalis pumila
#> 148 2003     1   25    29      N1P0       N2P0            physalis pumila
#> 149 2003     1   25    13      N1P0       N2P3              poa pratensis
#> 150 2003     1   25    29      N1P0       N2P0              poa pratensis
#> 151 2003     1   25    13      N1P0       N2P3        schrankia nuttallii
#> 153 2003     1   25    13      N1P0       N2P3     solidago missouriensis
#> 154 2003     1   25    29      N1P0       N2P0     solidago missouriensis
#> 155 2003     1   25    13      N1P0       N2P3         sorghastrum nutans
#> 156 2003     1   25    29      N1P0       N2P0         sorghastrum nutans
#> 157 2003     1   25    13      N1P0       N2P3           sporobolus asper
#> 159 2003     1   25    13      N1P0       N2P3          viola rafinesquii
#> 160 2003     1   25    29      N1P0       N2P0          viola rafinesquii
#> 162 2003     2   27    32      N1P0       N2P0      ambrosia psilostachya
#> 163 2003     2   27    21      N1P0       N2P3          amorpha canescens
#> 164 2003     2   27    32      N1P0       N2P0          amorpha canescens
#> 165 2003     2   27    21      N1P0       N2P3        andropogon gerardii
#> 166 2003     2   27    32      N1P0       N2P0        andropogon gerardii
#> 167 2003     2   27    21      N1P0       N2P3       andropogon scoparius
#> 168 2003     2   27    32      N1P0       N2P0       andropogon scoparius
#> 169 2003     2   27    21      N1P0       N2P3        antennaria neglecta
#> 171 2003     2   27    21      N1P0       N2P3      asclepias stenophylla
#> 172 2003     2   27    32      N1P0       N2P0      asclepias stenophylla
#> 173 2003     2   27    21      N1P0       N2P3         asclepias tuberosa
#> 174 2003     2   27    32      N1P0       N2P0         asclepias tuberosa
#> 175 2003     2   27    21      N1P0       N2P3     asclepias verticillata
#> 176 2003     2   27    32      N1P0       N2P0     asclepias verticillata
#> 177 2003     2   27    21      N1P0       N2P3            aster ericoides
#> 178 2003     2   27    32      N1P0       N2P0            aster ericoides
#> 180 2003     2   27    32      N1P0       N2P0        aster oblongifolius
#> 181 2003     2   27    21      N1P0       N2P3     bouteloua curtipendula
#> 182 2003     2   27    32      N1P0       N2P0     bouteloua curtipendula
#> 183 2003     2   27    21      N1P0       N2P3           carex heliophila
#> 184 2003     2   27    32      N1P0       N2P0           carex heliophila
#> 185 2003     2   27    21      N1P0       N2P3               carex meadii
#> 186 2003     2   27    32      N1P0       N2P0               carex meadii
#> 187 2003     2   27    21      N1P0       N2P3              dalea candida
#> 190 2003     2   27    32      N1P0       N2P0       delphinium virescens
#> 191 2003     2   27    21      N1P0       N2P3 dichanthelium oligosanthes
#> 192 2003     2   27    32      N1P0       N2P0 dichanthelium oligosanthes
#> 193 2003     2   27    21      N1P0       N2P3     eragrostis spectabilis
#> 196 2003     2   27    32      N1P0       N2P0          euphorbia serpens
#> 197 2003     2   27    21      N1P0       N2P3        koeleria pyramidata
#> 198 2003     2   27    32      N1P0       N2P0        koeleria pyramidata
#> 200 2003     2   27    32      N1P0       N2P0       kuhnia eupatorioides
#> 201 2003     2   27    21      N1P0       N2P3             linum sulcatum
#> 202 2003     2   27    32      N1P0       N2P0             linum sulcatum
#> 204 2003     2   27    32      N1P0       N2P0          panicum capillare
#> 205 2003     2   27    21      N1P0       N2P3            physalis pumila
#> 206 2003     2   27    32      N1P0       N2P0            physalis pumila
#> 207 2003     2   27    21      N1P0       N2P3              poa pratensis
#> 208 2003     2   27    32      N1P0       N2P0              poa pratensis
#> 209 2003     2   27    21      N1P0       N2P3            ruellia humilis
#> 210 2003     2   27    32      N1P0       N2P0            ruellia humilis
#> 212 2003     2   27    32      N1P0       N2P0         senecio plattensis
#> 213 2003     2   27    21      N1P0       N2P3        solidago canadensis
#> 215 2003     2   27    21      N1P0       N2P3     solidago missouriensis
#> 216 2003     2   27    32      N1P0       N2P0     solidago missouriensis
#> 217 2003     2   27    21      N1P0       N2P3         sorghastrum nutans
#> 218 2003     2   27    32      N1P0       N2P0         sorghastrum nutans
#> 219 2003     2   27    21      N1P0       N2P3           sporobolus asper
#> 220 2003     2   27    32      N1P0       N2P0           sporobolus asper
#> 221 2003     2   27    21      N1P0       N2P3           viola pedatifida
#>       difference
#> 2    0.009784736
#> 3    0.052532728
#> 4    0.011575488
#> 5   -0.060255980
#> 6    0.015684662
#> 7   -0.029633737
#> 8   -0.021659375
#> 10   0.001956947
#> 11  -0.007357934
#> 12   0.017408936
#> 13   0.024291498
#> 15   0.007108658
#> 16   0.010079732
#> 17   0.005677471
#> 18   0.034560269
#> 19  -0.021725677
#> 20  -0.024019345
#> 21  -0.006369427
#> 22  -0.002455533
#> 24   0.001956947
#> 25   0.007405210
#> 26   0.006664423
#> 27   0.005875172
#> 28  -0.004246285
#> 29   0.002024291
#> 31  -0.004345136
#> 32  -0.002455533
#> 33  -0.006369427
#> 34  -0.006369427
#> 35  -0.004246285
#> 36  -0.000332391
#> 38   0.005870841
#> 39  -0.004246285
#> 40  -0.004246285
#> 41  -0.056585609
#> 42  -0.016432539
#> 43   0.076923077
#> 45  -0.002123142
#> 46  -0.002123142
#> 47   0.002024291
#> 49  -0.003507053
#> 50  -0.022062398
#> 51   0.010757540
#> 52  -0.009140730
#> 53   0.010121457
#> 55   0.002024291
#> 57  -0.004474273
#> 58  -0.000671992
#> 59   0.046562410
#> 60   0.018339415
#> 61  -0.310116353
#> 62  -0.147327770
#> 63   0.281782858
#> 64  -0.014970951
#> 65   0.004784689
#> 66   0.002534854
#> 67  -0.006711409
#> 68  -0.006711409
#> 69  -0.005469745
#> 70   0.045099991
#> 71   0.033471415
#> 72   0.083871352
#> 73   0.004784689
#> 75   0.026760005
#> 76   0.017590867
#> 77   0.008573906
#> 78   0.000144606
#> 79   0.001594896
#> 82   0.006337136
#> 83  -0.028793766
#> 84  -0.016859332
#> 85   0.019138756
#> 86   0.003802281
#> 87  -0.004474273
#> 88  -0.004474273
#> 90   0.006337136
#> 91   0.000952657
#> 92   0.001565145
#> 93  -0.005116513
#> 94  -0.006711409
#> 95   0.003810625
#> 96   0.004993152
#> 97  -0.000642240
#> 98   0.005367427
#> 100  0.001267427
#> 101  0.001594896
#> 103 -0.035794183
#> 104 -0.023119912
#> 105 -0.025507638
#> 106  0.003691700
#> 107 -0.006711409
#> 108  0.019904561
#> 110  0.005468216
#> 111  0.100418410
#> 112  0.027341080
#> 113  0.006551015
#> 114  0.020145290
#> 115 -0.033595076
#> 116 -0.079168309
#> 118  0.001367054
#> 119  0.003752668
#> 120  0.068901276
#> 121  0.019525802
#> 123  0.050085939
#> 124  0.050347147
#> 126  0.002734108
#> 127 -0.003563792
#> 128  0.012840856
#> 129 -0.010101883
#> 130 -0.012263049
#> 131 -0.028510335
#> 132 -0.018940957
#> 133 -0.001425517
#> 134  0.005409753
#> 135  0.004184100
#> 137 -0.000154083
#> 138  0.013378226
#> 139  0.027585837
#> 140 -0.014255167
#> 142  0.006835270
#> 144  0.004101162
#> 145 -0.009978617
#> 146 -0.009978617
#> 147 -0.002851033
#> 148 -0.002851033
#> 149  0.006973501
#> 150  0.008202324
#> 151  0.069735007
#> 153 -0.034212402
#> 154 -0.030111240
#> 155 -0.165783423
#> 156 -0.058077871
#> 157  0.002789400
#> 159 -0.001425517
#> 160 -0.001425517
#> 162  0.002824859
#> 163  0.077244259
#> 164  0.028248588
#> 165 -0.045922749
#> 166  0.174581361
#> 167  0.144695844
#> 168 -0.138647121
#> 169  0.002087683
#> 171 -0.001501502
#> 172 -0.001501502
#> 173 -0.001501502
#> 174  0.009797933
#> 175 -0.007507508
#> 176 -0.007507508
#> 177 -0.011754970
#> 178  0.027179722
#> 180  0.015065913
#> 181 -0.033763409
#> 182 -0.033720161
#> 183 -0.007507508
#> 184  0.031098895
#> 185  0.002180155
#> 186  0.052947015
#> 187  0.002087683
#> 190  0.003766478
#> 191 -0.001861987
#> 192 -0.014506031
#> 193  0.020876827
#> 196  0.001883239
#> 197 -0.001501502
#> 198 -0.001501502
#> 200  0.009416196
#> 201 -0.003003003
#> 202 -0.003003003
#> 204  0.005649718
#> 205 -0.000915320
#> 206 -0.003003003
#> 207  0.014613779
#> 208  0.005649718
#> 209 -0.001501502
#> 210  0.007914694
#> 212  0.001883239
#> 213  0.002087683
#> 215 -0.036786787
#> 216 -0.022662493
#> 217 -0.115020031
#> 218 -0.168804398
#> 219  0.002087683
#> 220  0.016949153
#> 221  0.002087683

# Pooling by treatment with time
df <- subset(pplots, year < 2004)
abundance_difference(df = df,
                     species.var = "species",
                     abundance.var = "relative_cover",
                     treatment.var = "treatment",
                     pool = TRUE,
                     replicate.var = "plot",
                     time.var = "year")
#>     year treatment treatment2                    species    difference
#> 2   2002      N1P0       N2P0       achillea millefolium  1.010101e-03
#> 3   2002      N2P0       N2P3       achillea millefolium -1.010101e-03
#> 4   2002      N2P0       N2P3      ambrosia psilostachya  2.384359e-03
#> 5   2002      N1P0       N2P3      ambrosia psilostachya  2.669693e-03
#> 6   2002      N1P0       N2P0      ambrosia psilostachya  2.853340e-04
#> 7   2002      N2P0       N2P3          amorpha canescens -3.379951e-02
#> 8   2002      N1P0       N2P3          amorpha canescens -9.733626e-03
#> 9   2002      N1P0       N2P0          amorpha canescens  2.406589e-02
#> 10  2002      N2P0       N2P3        andropogon gerardii -7.188126e-02
#> 11  2002      N1P0       N2P3        andropogon gerardii -6.204108e-02
#> 12  2002      N1P0       N2P0        andropogon gerardii  9.840181e-03
#> 13  2002      N1P0       N2P0       andropogon scoparius -4.854132e-02
#> 14  2002      N1P0       N2P3       andropogon scoparius  5.282351e-02
#> 15  2002      N2P0       N2P3       andropogon scoparius  1.013648e-01
#> 16  2002      N2P0       N2P3        antennaria neglecta -1.172517e-05
#> 17  2002      N1P0       N2P3        antennaria neglecta -5.848583e-04
#> 18  2002      N1P0       N2P0        antennaria neglecta -5.731332e-04
#> 19  2002      N2P0       N2P3      asclepias stenophylla -3.211303e-04
#> 20  2002      N1P0       N2P3      asclepias stenophylla -5.527917e-04
#> 21  2002      N1P0       N2P0      asclepias stenophylla -2.316613e-04
#> 22  2002      N2P0       N2P3     asclepias verticillata -5.977432e-04
#> 23  2002      N1P0       N2P3     asclepias verticillata -2.101134e-03
#> 24  2002      N1P0       N2P0     asclepias verticillata -1.503391e-03
#> 25  2002      N2P0       N2P3          asclepias viridis -1.605652e-03
#> 26  2002      N1P0       N2P0          asclepias viridis  1.605652e-03
#> 28  2002      N2P0       N2P3            aster ericoides -2.408576e-02
#> 29  2002      N1P0       N2P3            aster ericoides -2.388115e-02
#> 30  2002      N1P0       N2P0            aster ericoides  2.046082e-04
#> 31  2002      N2P0       N2P3        aster oblongifolius  3.395586e-03
#> 32  2002      N1P0       N2P0        aster oblongifolius -3.040354e-03
#> 33  2002      N1P0       N2P3        aster oblongifolius  3.552318e-04
#> 34  2002      N2P0       N2P3             aster sericeus  4.048583e-03
#> 36  2002      N1P0       N2P3             aster sericeus  4.048583e-03
#> 38  2002      N1P0       N2P0         baptisia australis -1.152605e-03
#> 39  2002      N1P0       N2P3         baptisia australis -1.152605e-03
#> 40  2002      N1P0       N2P3         baptisia bracteata  2.256609e-03
#> 42  2002      N2P0       N2P3         baptisia bracteata  2.256609e-03
#> 43  2002      N2P0       N2P3     bouteloua curtipendula -3.729620e-03
#> 44  2002      N1P0       N2P0     bouteloua curtipendula  1.289029e-02
#> 45  2002      N1P0       N2P3     bouteloua curtipendula  9.160668e-03
#> 46  2002      N2P0       N2P3         bouteloua gracilis  5.659310e-04
#> 48  2002      N1P0       N2P3         bouteloua gracilis  5.659310e-04
#> 49  2002      N2P0       N2P3              carex brevior  7.974482e-04
#> 51  2002      N1P0       N2P3              carex brevior  7.974482e-04
#> 52  2002      N1P0       N2P3           carex heliophila  3.789989e-03
#> 53  2002      N1P0       N2P0           carex heliophila  5.908710e-04
#> 54  2002      N2P0       N2P3           carex heliophila  3.199118e-03
#> 55  2002      N2P0       N2P3               carex meadii -1.881362e-03
#> 56  2002      N1P0       N2P0               carex meadii -1.118458e-02
#> 57  2002      N1P0       N2P3               carex meadii -1.306594e-02
#> 58  2002      N1P0       N2P0              dalea candida -2.943957e-03
#> 59  2002      N1P0       N2P3              dalea candida -2.226235e-03
#> 60  2002      N2P0       N2P3              dalea candida  7.177222e-04
#> 61  2002      N1P0       N2P0             dalea purpurea  3.261578e-04
#> 62  2002      N1P0       N2P3             dalea purpurea  1.921230e-03
#> 63  2002      N2P0       N2P3             dalea purpurea  1.595072e-03
#> 64  2002      N2P0       N2P3   dichanthelium acuminatum -1.056189e-03
#> 65  2002      N1P0       N2P0   dichanthelium acuminatum  1.056189e-03
#> 67  2002      N2P0       N2P3 dichanthelium oligosanthes -5.564620e-03
#> 68  2002      N1P0       N2P0 dichanthelium oligosanthes -3.852048e-04
#> 69  2002      N1P0       N2P3 dichanthelium oligosanthes -5.949825e-03
#> 70  2002      N1P0       N2P3              draba reptans -3.248863e-04
#> 71  2002      N1P0       N2P0              draba reptans -3.248863e-04
#> 73  2002      N1P0       N2P0     eragrostis spectabilis -2.798988e-03
#> 74  2002      N1P0       N2P3     eragrostis spectabilis  5.688483e-03
#> 75  2002      N2P0       N2P3     eragrostis spectabilis  8.487471e-03
#> 76  2002      N2P0       N2P3          euphorbia serpens  5.775355e-04
#> 78  2002      N1P0       N2P3          euphorbia serpens  5.775355e-04
#> 79  2002      N1P0       N2P3       euphorbia spathulata  2.401537e-04
#> 81  2002      N2P0       N2P3       euphorbia spathulata  2.401537e-04
#> 82  2002      N1P0       N2P3        koeleria pyramidata -1.552866e-03
#> 83  2002      N1P0       N2P0        koeleria pyramidata -3.660833e-03
#> 84  2002      N2P0       N2P3        koeleria pyramidata  2.107967e-03
#> 85  2002      N1P0       N2P0       kuhnia eupatorioides -2.140531e-03
#> 86  2002      N1P0       N2P3       kuhnia eupatorioides -4.528819e-03
#> 87  2002      N2P0       N2P3       kuhnia eupatorioides -2.388289e-03
#> 88  2002      N1P0       N2P0           liatris punctata  3.198977e-04
#> 90  2002      N2P0       N2P3           liatris punctata -3.198977e-04
#> 91  2002      N1P0       N2P3             linum sulcatum -2.552010e-03
#> 92  2002      N1P0       N2P0             linum sulcatum -1.135327e-03
#> 93  2002      N2P0       N2P3             linum sulcatum -1.416683e-03
#> 94  2002      N2P0       N2P3     muhlenbergia cuspidata -9.784735e-04
#> 95  2002      N1P0       N2P0     muhlenbergia cuspidata  9.784735e-04
#> 97  2002      N1P0       N2P3             oxalis stricta -1.974723e-04
#> 98  2002      N1P0       N2P0             oxalis stricta -1.974723e-04
#> 100 2002      N1P0       N2P3            physalis pumila -2.236095e-03
#> 101 2002      N1P0       N2P0            physalis pumila -3.702679e-03
#> 102 2002      N2P0       N2P3            physalis pumila  1.466584e-03
#> 103 2002      N1P0       N2P3              poa pratensis  9.608113e-03
#> 104 2002      N1P0       N2P0              poa pratensis  2.188519e-02
#> 105 2002      N2P0       N2P3              poa pratensis -1.227708e-02
#> 107 2002      N1P0       N2P0       ratibida columnifera -6.497725e-04
#> 108 2002      N1P0       N2P3       ratibida columnifera -6.497725e-04
#> 109 2002      N1P0       N2P3            ruellia humilis  2.384479e-03
#> 110 2002      N1P0       N2P0            ruellia humilis  1.106038e-03
#> 111 2002      N2P0       N2P3            ruellia humilis  1.278441e-03
#> 112 2002      N1P0       N2P3              salvia azurea  9.276235e-03
#> 113 2002      N1P0       N2P0              salvia azurea -3.949447e-04
#> 114 2002      N2P0       N2P3              salvia azurea  9.671180e-03
#> 115 2002      N1P0       N2P3        schrankia nuttallii  1.282051e-02
#> 117 2002      N2P0       N2P3        schrankia nuttallii  1.282051e-02
#> 118 2002      N2P0       N2P3         senecio plattensis -2.112378e-04
#> 119 2002      N1P0       N2P3         senecio plattensis -1.003629e-03
#> 120 2002      N1P0       N2P0         senecio plattensis -7.923917e-04
#> 121 2002      N1P0       N2P3     sisyrinchium campestre -4.613727e-04
#> 122 2002      N1P0       N2P0     sisyrinchium campestre -2.855080e-04
#> 123 2002      N2P0       N2P3     sisyrinchium campestre -1.758647e-04
#> 124 2002      N2P0       N2P3        solidago canadensis  2.658160e-04
#> 125 2002      N1P0       N2P3        solidago canadensis  2.658160e-04
#> 127 2002      N2P0       N2P3     solidago missouriensis  1.867275e-03
#> 128 2002      N1P0       N2P3     solidago missouriensis -2.515332e-03
#> 129 2002      N1P0       N2P0     solidago missouriensis -4.382607e-03
#> 130 2002      N2P0       N2P3         sorghastrum nutans  1.632421e-02
#> 131 2002      N1P0       N2P3         sorghastrum nutans  1.336085e-02
#> 132 2002      N1P0       N2P0         sorghastrum nutans -2.963363e-03
#> 133 2002      N1P0       N2P0        spermolepis inermis  3.367003e-04
#> 135 2002      N2P0       N2P3        spermolepis inermis -3.367003e-04
#> 136 2002      N2P0       N2P3           sporobolus asper  5.735291e-03
#> 137 2002      N1P0       N2P3           sporobolus asper  6.101063e-03
#> 138 2002      N1P0       N2P0           sporobolus asper  3.657718e-04
#> 139 2002      N2P0       N2P3     sporobolus heterolepis -1.862556e-02
#> 140 2002      N1P0       N2P3     sporobolus heterolepis -2.962085e-03
#> 141 2002      N1P0       N2P0     sporobolus heterolepis  1.566348e-02
#> 142 2002      N2P0       N2P3       triodanis perfoliata  1.443467e-03
#> 143 2002      N1P0       N2P3       triodanis perfoliata  1.561460e-03
#> 144 2002      N1P0       N2P0       triodanis perfoliata  1.179933e-04
#> 145 2002      N2P0       N2P3          viola rafinesquii -3.367003e-04
#> 146 2002      N1P0       N2P0          viola rafinesquii  3.367003e-04
#> 148 2003      N1P0       N2P0       achillea millefolium  2.391200e-04
#> 150 2003      N2P0       N2P3       achillea millefolium -2.391200e-04
#> 152 2003      N1P0       N2P3    ambrosia artemisiifolia  2.472800e-04
#> 153 2003      N2P0       N2P3    ambrosia artemisiifolia  2.472800e-04
#> 154 2003      N1P0       N2P0      ambrosia psilostachya -4.219591e-03
#> 155 2003      N1P0       N2P3      ambrosia psilostachya  1.864372e-02
#> 156 2003      N2P0       N2P3      ambrosia psilostachya  2.286331e-02
#> 157 2003      N1P0       N2P0          amorpha canescens  9.876721e-03
#> 158 2003      N1P0       N2P3          amorpha canescens -1.145582e-02
#> 159 2003      N2P0       N2P3          amorpha canescens -2.133254e-02
#> 160 2003      N1P0       N2P0        andropogon gerardii  3.942949e-02
#> 161 2003      N1P0       N2P3        andropogon gerardii  3.326461e-02
#> 162 2003      N2P0       N2P3        andropogon gerardii -6.164879e-03
#> 163 2003      N1P0       N2P0       andropogon scoparius -5.999543e-02
#> 164 2003      N1P0       N2P3       andropogon scoparius  4.910991e-02
#> 165 2003      N2P0       N2P3       andropogon scoparius  1.091053e-01
#> 166 2003      N1P0       N2P3        antennaria neglecta -2.420602e-03
#> 167 2003      N1P0       N2P0        antennaria neglecta -2.411661e-03
#> 168 2003      N2P0       N2P3        antennaria neglecta -8.940833e-06
#> 169 2003      N1P0       N2P3      asclepias stenophylla -1.154560e-03
#> 170 2003      N1P0       N2P0      asclepias stenophylla -9.906955e-04
#> 171 2003      N2P0       N2P3      asclepias stenophylla -1.638643e-04
#> 172 2003      N2P0       N2P3         asclepias tuberosa -1.883239e-03
#> 173 2003      N1P0       N2P0         asclepias tuberosa  1.632989e-03
#> 174 2003      N1P0       N2P3         asclepias tuberosa -2.502503e-04
#> 175 2003      N1P0       N2P0     asclepias verticillata -2.053912e-03
#> 176 2003      N1P0       N2P3     asclepias verticillata -2.346545e-03
#> 177 2003      N2P0       N2P3     asclepias verticillata -2.926322e-04
#> 179 2003      N1P0       N2P0          asclepias viridis  4.257130e-04
#> 180 2003      N2P0       N2P3          asclepias viridis -4.257130e-04
#> 181 2003      N1P0       N2P3            aster ericoides -9.455183e-03
#> 182 2003      N1P0       N2P0            aster ericoides  5.791998e-03
#> 183 2003      N2P0       N2P3            aster ericoides -1.524718e-02
#> 184 2003      N2P0       N2P3        aster oblongifolius -1.382317e-03
#> 185 2003      N1P0       N2P0        aster oblongifolius  1.153660e-04
#> 186 2003      N1P0       N2P3        aster oblongifolius -1.266951e-03
#> 187 2003      N1P0       N2P3             aster sericeus  3.254300e-03
#> 189 2003      N2P0       N2P3             aster sericeus  3.254300e-03
#> 191 2003      N1P0       N2P3         baptisia australis -8.992805e-04
#> 192 2003      N1P0       N2P0         baptisia australis -8.992805e-04
#> 193 2003      N2P0       N2P3     bouteloua curtipendula -1.376923e-02
#> 194 2003      N1P0       N2P0     bouteloua curtipendula  1.442992e-03
#> 195 2003      N1P0       N2P3     bouteloua curtipendula -1.232624e-02
#> 196 2003      N1P0       N2P0         bouteloua gracilis  4.556847e-04
#> 198 2003      N2P0       N2P3         bouteloua gracilis -4.556847e-04
#> 199 2003      N1P0       N2P3           carex heliophila -1.142505e-02
#> 200 2003      N1P0       N2P0           carex heliophila -8.652405e-03
#> 201 2003      N2P0       N2P3           carex heliophila -2.772648e-03
#> 202 2003      N2P0       N2P3               carex meadii -7.648920e-03
#> 203 2003      N1P0       N2P3               carex meadii -1.852583e-02
#> 204 2003      N1P0       N2P0               carex meadii -1.087691e-02
#> 205 2003      N2P0       N2P3          cyperus lupulinus  5.236973e-04
#> 207 2003      N1P0       N2P3          cyperus lupulinus  5.236973e-04
#> 208 2003      N1P0       N2P3              dalea candida -8.932125e-03
#> 209 2003      N1P0       N2P0              dalea candida -1.085009e-02
#> 210 2003      N2P0       N2P3              dalea candida  1.917963e-03
#> 211 2003      N2P0       N2P3             dalea purpurea -1.139212e-03
#> 212 2003      N1P0       N2P0             dalea purpurea  6.125733e-05
#> 213 2003      N1P0       N2P3             dalea purpurea -1.077954e-03
#> 214 2003      N1P0       N2P3       delphinium virescens  2.472800e-04
#> 215 2003      N1P0       N2P0       delphinium virescens  1.345106e-03
#> 216 2003      N2P0       N2P3       delphinium virescens -1.097826e-03
#> 217 2003      N2P0       N2P3   dichanthelium acuminatum  6.973500e-04
#> 219 2003      N1P0       N2P3   dichanthelium acuminatum  6.973500e-04
#> 220 2003      N1P0       N2P3 dichanthelium oligosanthes  4.244633e-05
#> 221 2003      N1P0       N2P0 dichanthelium oligosanthes  1.962984e-03
#> 222 2003      N2P0       N2P3 dichanthelium oligosanthes -1.920537e-03
#> 223 2003      N2P0       N2P3     eragrostis spectabilis  1.054411e-02
#> 224 2003      N1P0       N2P0     eragrostis spectabilis -3.659027e-04
#> 225 2003      N1P0       N2P3     eragrostis spectabilis  1.017821e-02
#> 226 2003      N1P0       N2P3         erigeron strigosus -2.997602e-04
#> 227 2003      N1P0       N2P0         erigeron strigosus -2.997602e-04
#> 229 2003      N2P0       N2P3          euphorbia serpens -6.897548e-04
#> 230 2003      N1P0       N2P3          euphorbia serpens  8.433630e-04
#> 231 2003      N1P0       N2P0          euphorbia serpens  1.533118e-03
#> 232 2003      N2P0       N2P3        koeleria pyramidata -1.587480e-03
#> 233 2003      N1P0       N2P0        koeleria pyramidata -1.573776e-03
#> 234 2003      N1P0       N2P3        koeleria pyramidata -3.161256e-03
#> 235 2003      N1P0       N2P0       kuhnia eupatorioides -6.799394e-03
#> 236 2003      N1P0       N2P3       kuhnia eupatorioides -7.059517e-03
#> 237 2003      N2P0       N2P3       kuhnia eupatorioides -2.601227e-04
#> 238 2003      N1P0       N2P3             linum sulcatum -2.386518e-04
#> 239 2003      N1P0       N2P0             linum sulcatum -5.005005e-04
#> 240 2003      N2P0       N2P3             linum sulcatum  2.618487e-04
#> 241 2003      N2P0       N2P3             oxalis stricta  5.091287e-04
#> 242 2003      N1P0       N2P3             oxalis stricta -4.458117e-05
#> 243 2003      N1P0       N2P0             oxalis stricta -5.537098e-04
#> 244 2003      N2P0       N2P3          panicum capillare -9.416197e-04
#> 245 2003      N1P0       N2P0          panicum capillare  9.416197e-04
#> 247 2003      N1P0       N2P3            physalis pumila  1.128015e-04
#> 248 2003      N1P0       N2P0            physalis pumila -1.806238e-03
#> 249 2003      N2P0       N2P3            physalis pumila  1.919039e-03
#> 250 2003      N2P0       N2P3              poa pratensis  1.530744e-03
#> 251 2003      N1P0       N2P0              poa pratensis  5.034822e-03
#> 252 2003      N1P0       N2P3              poa pratensis  6.565566e-03
#> 253 2003      N2P0       N2P3            ruellia humilis  5.368031e-03
#> 254 2003      N1P0       N2P0            ruellia humilis  4.242950e-05
#> 255 2003      N1P0       N2P3            ruellia humilis  5.410461e-03
#> 256 2003      N1P0       N2P0              salvia azurea -3.045404e-03
#> 257 2003      N1P0       N2P3              salvia azurea  2.291899e-02
#> 258 2003      N2P0       N2P3              salvia azurea  2.596439e-02
#> 259 2003      N1P0       N2P3        schrankia nuttallii  1.162250e-02
#> 261 2003      N2P0       N2P3        schrankia nuttallii  1.162250e-02
#> 262 2003      N2P0       N2P3         senecio plattensis -3.138732e-04
#> 263 2003      N1P0       N2P0         senecio plattensis  7.302533e-05
#> 264 2003      N1P0       N2P3         senecio plattensis -2.408478e-04
#> 265 2003      N2P0       N2P3        solidago canadensis  3.479472e-04
#> 267 2003      N1P0       N2P3        solidago canadensis  3.479472e-04
#> 268 2003      N1P0       N2P0     solidago missouriensis -8.625903e-03
#> 269 2003      N1P0       N2P3     solidago missouriensis -1.294062e-02
#> 270 2003      N2P0       N2P3     solidago missouriensis -4.314715e-03
#> 271 2003      N1P0       N2P0         sorghastrum nutans  2.949173e-02
#> 272 2003      N1P0       N2P3         sorghastrum nutans -5.664992e-02
#> 273 2003      N2P0       N2P3         sorghastrum nutans -8.614165e-02
#> 274 2003      N1P0       N2P0           sporobolus asper  2.736163e-03
#> 275 2003      N1P0       N2P3           sporobolus asper  1.109136e-03
#> 276 2003      N2P0       N2P3           sporobolus asper -1.627027e-03
#> 277 2003      N1P0       N2P0     sporobolus heterolepis  2.212582e-02
#> 278 2003      N1P0       N2P3     sporobolus heterolepis -3.078374e-03
#> 279 2003      N2P0       N2P3     sporobolus heterolepis -2.520419e-02
#> 281 2003      N1P0       N2P3           viola pedatifida  3.479472e-04
#> 282 2003      N2P0       N2P3           viola pedatifida  3.479472e-04
#> 283 2003      N1P0       N2P0          viola rafinesquii -2.375862e-04
#> 284 2003      N1P0       N2P3          viola rafinesquii -2.375862e-04

# All pairwise replicates with treatment
df <- subset(pplots, year < 2004 & plot %in% c(21, 25, 32))
abundance_difference(df = df,
                     species.var = "species",
                     abundance.var = "relative_cover",
                     replicate.var = "plot",
                     time.var = "year",
                     treatment.var = "treatment")
#>     year plot plot2 treatment treatment2                    species
#> 2   2002   21    32      N2P3       N2P0      ambrosia psilostachya
#> 3   2002   25    32      N1P0       N2P0      ambrosia psilostachya
#> 4   2002   21    25      N2P3       N1P0          amorpha canescens
#> 5   2002   21    32      N2P3       N2P0          amorpha canescens
#> 6   2002   25    32      N1P0       N2P0          amorpha canescens
#> 7   2002   21    25      N2P3       N1P0        andropogon gerardii
#> 8   2002   21    32      N2P3       N2P0        andropogon gerardii
#> 9   2002   25    32      N1P0       N2P0        andropogon gerardii
#> 10  2002   21    25      N2P3       N1P0       andropogon scoparius
#> 11  2002   21    32      N2P3       N2P0       andropogon scoparius
#> 12  2002   25    32      N1P0       N2P0       andropogon scoparius
#> 13  2002   21    25      N2P3       N1P0        antennaria neglecta
#> 14  2002   21    32      N2P3       N2P0        antennaria neglecta
#> 15  2002   25    32      N1P0       N2P0        antennaria neglecta
#> 16  2002   21    25      N2P3       N1P0            aster ericoides
#> 17  2002   21    32      N2P3       N2P0            aster ericoides
#> 18  2002   25    32      N1P0       N2P0            aster ericoides
#> 19  2002   21    25      N2P3       N1P0     bouteloua curtipendula
#> 20  2002   21    32      N2P3       N2P0     bouteloua curtipendula
#> 21  2002   25    32      N1P0       N2P0     bouteloua curtipendula
#> 22  2002   21    25      N2P3       N1P0              carex brevior
#> 23  2002   21    32      N2P3       N2P0              carex brevior
#> 25  2002   21    25      N2P3       N1P0           carex heliophila
#> 26  2002   21    32      N2P3       N2P0           carex heliophila
#> 27  2002   25    32      N1P0       N2P0           carex heliophila
#> 28  2002   21    25      N2P3       N1P0               carex meadii
#> 29  2002   21    32      N2P3       N2P0               carex meadii
#> 30  2002   25    32      N1P0       N2P0               carex meadii
#> 31  2002   21    25      N2P3       N1P0              dalea candida
#> 32  2002   21    32      N2P3       N2P0              dalea candida
#> 33  2002   25    32      N1P0       N2P0              dalea candida
#> 35  2002   21    32      N2P3       N2P0   dichanthelium acuminatum
#> 36  2002   25    32      N1P0       N2P0   dichanthelium acuminatum
#> 37  2002   21    25      N2P3       N1P0 dichanthelium oligosanthes
#> 38  2002   21    32      N2P3       N2P0 dichanthelium oligosanthes
#> 39  2002   25    32      N1P0       N2P0 dichanthelium oligosanthes
#> 40  2002   21    25      N2P3       N1P0     eragrostis spectabilis
#> 41  2002   21    32      N2P3       N2P0     eragrostis spectabilis
#> 42  2002   25    32      N1P0       N2P0     eragrostis spectabilis
#> 43  2002   21    25      N2P3       N1P0        koeleria pyramidata
#> 45  2002   25    32      N1P0       N2P0        koeleria pyramidata
#> 46  2002   21    25      N2P3       N1P0       kuhnia eupatorioides
#> 47  2002   21    32      N2P3       N2P0       kuhnia eupatorioides
#> 48  2002   25    32      N1P0       N2P0       kuhnia eupatorioides
#> 49  2002   21    25      N2P3       N1P0             linum sulcatum
#> 50  2002   21    32      N2P3       N2P0             linum sulcatum
#> 51  2002   25    32      N1P0       N2P0             linum sulcatum
#> 52  2002   21    25      N2P3       N1P0            physalis pumila
#> 53  2002   21    32      N2P3       N2P0            physalis pumila
#> 54  2002   25    32      N1P0       N2P0            physalis pumila
#> 55  2002   21    25      N2P3       N1P0              poa pratensis
#> 56  2002   21    32      N2P3       N2P0              poa pratensis
#> 57  2002   25    32      N1P0       N2P0              poa pratensis
#> 58  2002   21    25      N2P3       N1P0            ruellia humilis
#> 59  2002   21    32      N2P3       N2P0            ruellia humilis
#> 60  2002   25    32      N1P0       N2P0            ruellia humilis
#> 61  2002   21    25      N2P3       N1P0         senecio plattensis
#> 62  2002   21    32      N2P3       N2P0         senecio plattensis
#> 63  2002   25    32      N1P0       N2P0         senecio plattensis
#> 64  2002   21    25      N2P3       N1P0        solidago canadensis
#> 65  2002   21    32      N2P3       N2P0        solidago canadensis
#> 67  2002   21    25      N2P3       N1P0     solidago missouriensis
#> 68  2002   21    32      N2P3       N2P0     solidago missouriensis
#> 69  2002   25    32      N1P0       N2P0     solidago missouriensis
#> 70  2002   21    25      N2P3       N1P0         sorghastrum nutans
#> 71  2002   21    32      N2P3       N2P0         sorghastrum nutans
#> 72  2002   25    32      N1P0       N2P0         sorghastrum nutans
#> 74  2002   21    32      N2P3       N2P0           sporobolus asper
#> 75  2002   25    32      N1P0       N2P0           sporobolus asper
#> 77  2003   21    32      N2P3       N2P0      ambrosia psilostachya
#> 78  2003   25    32      N1P0       N2P0      ambrosia psilostachya
#> 79  2003   21    25      N2P3       N1P0          amorpha canescens
#> 80  2003   21    32      N2P3       N2P0          amorpha canescens
#> 81  2003   25    32      N1P0       N2P0          amorpha canescens
#> 82  2003   21    25      N2P3       N1P0        andropogon gerardii
#> 83  2003   21    32      N2P3       N2P0        andropogon gerardii
#> 84  2003   25    32      N1P0       N2P0        andropogon gerardii
#> 85  2003   21    25      N2P3       N1P0       andropogon scoparius
#> 86  2003   21    32      N2P3       N2P0       andropogon scoparius
#> 87  2003   25    32      N1P0       N2P0       andropogon scoparius
#> 88  2003   21    25      N2P3       N1P0        antennaria neglecta
#> 89  2003   21    32      N2P3       N2P0        antennaria neglecta
#> 92  2003   21    32      N2P3       N2P0         asclepias tuberosa
#> 93  2003   25    32      N1P0       N2P0         asclepias tuberosa
#> 94  2003   21    25      N2P3       N1P0            aster ericoides
#> 95  2003   21    32      N2P3       N2P0            aster ericoides
#> 96  2003   25    32      N1P0       N2P0            aster ericoides
#> 98  2003   21    32      N2P3       N2P0        aster oblongifolius
#> 99  2003   25    32      N1P0       N2P0        aster oblongifolius
#> 100 2003   21    25      N2P3       N1P0     bouteloua curtipendula
#> 101 2003   21    32      N2P3       N2P0     bouteloua curtipendula
#> 102 2003   25    32      N1P0       N2P0     bouteloua curtipendula
#> 103 2003   21    25      N2P3       N1P0           carex heliophila
#> 104 2003   21    32      N2P3       N2P0           carex heliophila
#> 105 2003   25    32      N1P0       N2P0           carex heliophila
#> 106 2003   21    25      N2P3       N1P0               carex meadii
#> 107 2003   21    32      N2P3       N2P0               carex meadii
#> 108 2003   25    32      N1P0       N2P0               carex meadii
#> 109 2003   21    25      N2P3       N1P0              dalea candida
#> 110 2003   21    32      N2P3       N2P0              dalea candida
#> 111 2003   25    32      N1P0       N2P0              dalea candida
#> 112 2003   21    25      N2P3       N1P0             dalea purpurea
#> 114 2003   25    32      N1P0       N2P0             dalea purpurea
#> 116 2003   21    32      N2P3       N2P0       delphinium virescens
#> 117 2003   25    32      N1P0       N2P0       delphinium virescens
#> 118 2003   21    25      N2P3       N1P0 dichanthelium oligosanthes
#> 119 2003   21    32      N2P3       N2P0 dichanthelium oligosanthes
#> 120 2003   25    32      N1P0       N2P0 dichanthelium oligosanthes
#> 121 2003   21    25      N2P3       N1P0     eragrostis spectabilis
#> 122 2003   21    32      N2P3       N2P0     eragrostis spectabilis
#> 123 2003   25    32      N1P0       N2P0     eragrostis spectabilis
#> 125 2003   21    32      N2P3       N2P0          euphorbia serpens
#> 126 2003   25    32      N1P0       N2P0          euphorbia serpens
#> 127 2003   21    25      N2P3       N1P0       kuhnia eupatorioides
#> 128 2003   21    32      N2P3       N2P0       kuhnia eupatorioides
#> 129 2003   25    32      N1P0       N2P0       kuhnia eupatorioides
#> 131 2003   21    32      N2P3       N2P0          panicum capillare
#> 132 2003   25    32      N1P0       N2P0          panicum capillare
#> 133 2003   21    25      N2P3       N1P0            physalis pumila
#> 134 2003   21    32      N2P3       N2P0            physalis pumila
#> 135 2003   25    32      N1P0       N2P0            physalis pumila
#> 136 2003   21    25      N2P3       N1P0              poa pratensis
#> 137 2003   21    32      N2P3       N2P0              poa pratensis
#> 138 2003   25    32      N1P0       N2P0              poa pratensis
#> 140 2003   21    32      N2P3       N2P0            ruellia humilis
#> 141 2003   25    32      N1P0       N2P0            ruellia humilis
#> 143 2003   21    32      N2P3       N2P0         senecio plattensis
#> 144 2003   25    32      N1P0       N2P0         senecio plattensis
#> 145 2003   21    25      N2P3       N1P0        solidago canadensis
#> 146 2003   21    32      N2P3       N2P0        solidago canadensis
#> 148 2003   21    25      N2P3       N1P0     solidago missouriensis
#> 149 2003   21    32      N2P3       N2P0     solidago missouriensis
#> 150 2003   25    32      N1P0       N2P0     solidago missouriensis
#> 151 2003   21    25      N2P3       N1P0         sorghastrum nutans
#> 152 2003   21    32      N2P3       N2P0         sorghastrum nutans
#> 153 2003   25    32      N1P0       N2P0         sorghastrum nutans
#> 154 2003   21    25      N2P3       N1P0           sporobolus asper
#> 155 2003   21    32      N2P3       N2P0           sporobolus asper
#> 156 2003   25    32      N1P0       N2P0           sporobolus asper
#> 157 2003   21    25      N2P3       N1P0           viola pedatifida
#> 158 2003   21    32      N2P3       N2P0           viola pedatifida
#> 160 2003   21    25      N2P3       N1P0          viola rafinesquii
#> 162 2003   25    32      N1P0       N2P0          viola rafinesquii
#>       difference
#> 2    0.003802281
#> 3    0.003802281
#> 4   -0.048913541
#> 5   -0.028222995
#> 6    0.020690546
#> 7    0.365617286
#> 8    0.162788583
#> 9   -0.202828703
#> 10  -0.348540720
#> 11  -0.296753809
#> 12   0.051786911
#> 13  -0.004784689
#> 14  -0.002249835
#> 15   0.002534854
#> 16   0.008462093
#> 17   0.050569736
#> 18   0.042107643
#> 19  -0.023425674
#> 20   0.050399937
#> 21   0.073825611
#> 22  -0.004784689
#> 23  -0.004784689
#> 25  -0.036164528
#> 26  -0.009169138
#> 27   0.026995390
#> 28   0.003139000
#> 29  -0.008429300
#> 30  -0.011568300
#> 31   0.004774531
#> 32  -0.001594896
#> 33  -0.006369427
#> 35   0.006337136
#> 36   0.006337136
#> 37  -0.001086967
#> 38   0.011934434
#> 39   0.013021401
#> 40  -0.014892471
#> 41  -0.015336475
#> 42  -0.000444004
#> 43   0.006369427
#> 45  -0.006369427
#> 46   0.006369427
#> 47   0.006337136
#> 48  -0.000032291
#> 49   0.001056492
#> 50   0.000612488
#> 51  -0.000444004
#> 52   0.002651389
#> 53  -0.001594896
#> 54  -0.004246285
#> 55   0.072166519
#> 56   0.001182527
#> 57  -0.070983992
#> 58  -0.001594896
#> 59   0.006009667
#> 60   0.007604563
#> 61   0.002123142
#> 62   0.001267427
#> 63  -0.000855715
#> 64  -0.001594896
#> 65  -0.001594896
#> 67   0.031847134
#> 68   0.012674271
#> 69  -0.019172863
#> 70  -0.018793364
#> 71   0.029199338
#> 72   0.047992702
#> 74   0.026615970
#> 75   0.026615970
#> 77   0.002824859
#> 78   0.002824859
#> 79  -0.077244259
#> 80  -0.048995671
#> 81   0.028248588
#> 82  -0.002343621
#> 83   0.220504110
#> 84   0.222847731
#> 85  -0.091185455
#> 86  -0.283342965
#> 87  -0.192157510
#> 88  -0.002087683
#> 89  -0.002087683
#> 92   0.011299435
#> 93   0.011299435
#> 94   0.013694186
#> 95   0.038934692
#> 96   0.025240506
#> 98   0.015065913
#> 99   0.015065913
#> 100 -0.013087077
#> 101  0.000043248
#> 102  0.013130325
#> 103  0.003563792
#> 104  0.038606403
#> 105  0.035042611
#> 106  0.005242271
#> 107  0.050766860
#> 108  0.045524589
#> 109  0.026422652
#> 110 -0.002087683
#> 111 -0.028510335
#> 112  0.001425517
#> 114 -0.001425517
#> 116  0.003766478
#> 117  0.003766478
#> 118 -0.045064483
#> 119 -0.012644044
#> 120  0.032420439
#> 121 -0.006621660
#> 122 -0.020876827
#> 123 -0.014255167
#> 125  0.001883239
#> 126  0.001883239
#> 127  0.009978617
#> 128  0.009416196
#> 129 -0.000562421
#> 131  0.005649718
#> 132  0.005649718
#> 133  0.000763350
#> 134 -0.002087683
#> 135 -0.002851033
#> 136 -0.014613779
#> 137 -0.008964061
#> 138  0.005649718
#> 140  0.009416196
#> 141  0.009416196
#> 143  0.001883239
#> 144  0.001883239
#> 145 -0.002087683
#> 146 -0.002087683
#> 148  0.034212402
#> 149  0.014124294
#> 150 -0.020088108
#> 151  0.161782759
#> 152 -0.053784367
#> 153 -0.215567126
#> 154 -0.002087683
#> 155  0.014861470
#> 156  0.016949153
#> 157 -0.002087683
#> 158 -0.002087683
#> 160  0.001425517
#> 162 -0.001425517

# All pairwise replicates without treatment
df <- subset(pplots, year < 2004 & plot %in% c(21, 25, 32))
abundance_difference(df = df,
                     species.var = "species",
                     abundance.var = "relative_cover",
                     replicate.var = "plot",
                     time.var = "year")
#>     year plot plot2                    species   difference
#> 2   2002   21    32      ambrosia psilostachya  0.003802281
#> 3   2002   25    32      ambrosia psilostachya  0.003802281
#> 4   2002   21    25          amorpha canescens -0.048913541
#> 5   2002   21    32          amorpha canescens -0.028222995
#> 6   2002   25    32          amorpha canescens  0.020690546
#> 7   2002   21    25        andropogon gerardii  0.365617286
#> 8   2002   21    32        andropogon gerardii  0.162788583
#> 9   2002   25    32        andropogon gerardii -0.202828703
#> 10  2002   21    25       andropogon scoparius -0.348540720
#> 11  2002   21    32       andropogon scoparius -0.296753809
#> 12  2002   25    32       andropogon scoparius  0.051786911
#> 13  2002   21    25        antennaria neglecta -0.004784689
#> 14  2002   21    32        antennaria neglecta -0.002249835
#> 15  2002   25    32        antennaria neglecta  0.002534854
#> 16  2002   21    25            aster ericoides  0.008462093
#> 17  2002   21    32            aster ericoides  0.050569736
#> 18  2002   25    32            aster ericoides  0.042107643
#> 19  2002   21    25     bouteloua curtipendula -0.023425674
#> 20  2002   21    32     bouteloua curtipendula  0.050399937
#> 21  2002   25    32     bouteloua curtipendula  0.073825611
#> 22  2002   21    25              carex brevior -0.004784689
#> 23  2002   21    32              carex brevior -0.004784689
#> 25  2002   21    25           carex heliophila -0.036164528
#> 26  2002   21    32           carex heliophila -0.009169138
#> 27  2002   25    32           carex heliophila  0.026995390
#> 28  2002   21    25               carex meadii  0.003139000
#> 29  2002   21    32               carex meadii -0.008429300
#> 30  2002   25    32               carex meadii -0.011568300
#> 31  2002   21    25              dalea candida  0.004774531
#> 32  2002   21    32              dalea candida -0.001594896
#> 33  2002   25    32              dalea candida -0.006369427
#> 35  2002   21    32   dichanthelium acuminatum  0.006337136
#> 36  2002   25    32   dichanthelium acuminatum  0.006337136
#> 37  2002   21    25 dichanthelium oligosanthes -0.001086967
#> 38  2002   21    32 dichanthelium oligosanthes  0.011934434
#> 39  2002   25    32 dichanthelium oligosanthes  0.013021401
#> 40  2002   21    25     eragrostis spectabilis -0.014892471
#> 41  2002   21    32     eragrostis spectabilis -0.015336475
#> 42  2002   25    32     eragrostis spectabilis -0.000444004
#> 43  2002   21    25        koeleria pyramidata  0.006369427
#> 45  2002   25    32        koeleria pyramidata -0.006369427
#> 46  2002   21    25       kuhnia eupatorioides  0.006369427
#> 47  2002   21    32       kuhnia eupatorioides  0.006337136
#> 48  2002   25    32       kuhnia eupatorioides -0.000032291
#> 49  2002   21    25             linum sulcatum  0.001056492
#> 50  2002   21    32             linum sulcatum  0.000612488
#> 51  2002   25    32             linum sulcatum -0.000444004
#> 52  2002   21    25            physalis pumila  0.002651389
#> 53  2002   21    32            physalis pumila -0.001594896
#> 54  2002   25    32            physalis pumila -0.004246285
#> 55  2002   21    25              poa pratensis  0.072166519
#> 56  2002   21    32              poa pratensis  0.001182527
#> 57  2002   25    32              poa pratensis -0.070983992
#> 58  2002   21    25            ruellia humilis -0.001594896
#> 59  2002   21    32            ruellia humilis  0.006009667
#> 60  2002   25    32            ruellia humilis  0.007604563
#> 61  2002   21    25         senecio plattensis  0.002123142
#> 62  2002   21    32         senecio plattensis  0.001267427
#> 63  2002   25    32         senecio plattensis -0.000855715
#> 64  2002   21    25        solidago canadensis -0.001594896
#> 65  2002   21    32        solidago canadensis -0.001594896
#> 67  2002   21    25     solidago missouriensis  0.031847134
#> 68  2002   21    32     solidago missouriensis  0.012674271
#> 69  2002   25    32     solidago missouriensis -0.019172863
#> 70  2002   21    25         sorghastrum nutans -0.018793364
#> 71  2002   21    32         sorghastrum nutans  0.029199338
#> 72  2002   25    32         sorghastrum nutans  0.047992702
#> 74  2002   21    32           sporobolus asper  0.026615970
#> 75  2002   25    32           sporobolus asper  0.026615970
#> 77  2003   21    32      ambrosia psilostachya  0.002824859
#> 78  2003   25    32      ambrosia psilostachya  0.002824859
#> 79  2003   21    25          amorpha canescens -0.077244259
#> 80  2003   21    32          amorpha canescens -0.048995671
#> 81  2003   25    32          amorpha canescens  0.028248588
#> 82  2003   21    25        andropogon gerardii -0.002343621
#> 83  2003   21    32        andropogon gerardii  0.220504110
#> 84  2003   25    32        andropogon gerardii  0.222847731
#> 85  2003   21    25       andropogon scoparius -0.091185455
#> 86  2003   21    32       andropogon scoparius -0.283342965
#> 87  2003   25    32       andropogon scoparius -0.192157510
#> 88  2003   21    25        antennaria neglecta -0.002087683
#> 89  2003   21    32        antennaria neglecta -0.002087683
#> 92  2003   21    32         asclepias tuberosa  0.011299435
#> 93  2003   25    32         asclepias tuberosa  0.011299435
#> 94  2003   21    25            aster ericoides  0.013694186
#> 95  2003   21    32            aster ericoides  0.038934692
#> 96  2003   25    32            aster ericoides  0.025240506
#> 98  2003   21    32        aster oblongifolius  0.015065913
#> 99  2003   25    32        aster oblongifolius  0.015065913
#> 100 2003   21    25     bouteloua curtipendula -0.013087077
#> 101 2003   21    32     bouteloua curtipendula  0.000043248
#> 102 2003   25    32     bouteloua curtipendula  0.013130325
#> 103 2003   21    25           carex heliophila  0.003563792
#> 104 2003   21    32           carex heliophila  0.038606403
#> 105 2003   25    32           carex heliophila  0.035042611
#> 106 2003   21    25               carex meadii  0.005242271
#> 107 2003   21    32               carex meadii  0.050766860
#> 108 2003   25    32               carex meadii  0.045524589
#> 109 2003   21    25              dalea candida  0.026422652
#> 110 2003   21    32              dalea candida -0.002087683
#> 111 2003   25    32              dalea candida -0.028510335
#> 112 2003   21    25             dalea purpurea  0.001425517
#> 114 2003   25    32             dalea purpurea -0.001425517
#> 116 2003   21    32       delphinium virescens  0.003766478
#> 117 2003   25    32       delphinium virescens  0.003766478
#> 118 2003   21    25 dichanthelium oligosanthes -0.045064483
#> 119 2003   21    32 dichanthelium oligosanthes -0.012644044
#> 120 2003   25    32 dichanthelium oligosanthes  0.032420439
#> 121 2003   21    25     eragrostis spectabilis -0.006621660
#> 122 2003   21    32     eragrostis spectabilis -0.020876827
#> 123 2003   25    32     eragrostis spectabilis -0.014255167
#> 125 2003   21    32          euphorbia serpens  0.001883239
#> 126 2003   25    32          euphorbia serpens  0.001883239
#> 127 2003   21    25       kuhnia eupatorioides  0.009978617
#> 128 2003   21    32       kuhnia eupatorioides  0.009416196
#> 129 2003   25    32       kuhnia eupatorioides -0.000562421
#> 131 2003   21    32          panicum capillare  0.005649718
#> 132 2003   25    32          panicum capillare  0.005649718
#> 133 2003   21    25            physalis pumila  0.000763350
#> 134 2003   21    32            physalis pumila -0.002087683
#> 135 2003   25    32            physalis pumila -0.002851033
#> 136 2003   21    25              poa pratensis -0.014613779
#> 137 2003   21    32              poa pratensis -0.008964061
#> 138 2003   25    32              poa pratensis  0.005649718
#> 140 2003   21    32            ruellia humilis  0.009416196
#> 141 2003   25    32            ruellia humilis  0.009416196
#> 143 2003   21    32         senecio plattensis  0.001883239
#> 144 2003   25    32         senecio plattensis  0.001883239
#> 145 2003   21    25        solidago canadensis -0.002087683
#> 146 2003   21    32        solidago canadensis -0.002087683
#> 148 2003   21    25     solidago missouriensis  0.034212402
#> 149 2003   21    32     solidago missouriensis  0.014124294
#> 150 2003   25    32     solidago missouriensis -0.020088108
#> 151 2003   21    25         sorghastrum nutans  0.161782759
#> 152 2003   21    32         sorghastrum nutans -0.053784367
#> 153 2003   25    32         sorghastrum nutans -0.215567126
#> 154 2003   21    25           sporobolus asper -0.002087683
#> 155 2003   21    32           sporobolus asper  0.014861470
#> 156 2003   25    32           sporobolus asper  0.016949153
#> 157 2003   21    25           viola pedatifida -0.002087683
#> 158 2003   21    32           viola pedatifida -0.002087683
#> 160 2003   21    25          viola rafinesquii  0.001425517
#> 162 2003   25    32          viola rafinesquii -0.001425517