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Calculates the abundance change for species in a replicate between two time points. Changes are on abundance values provided, if relative data is used, then changes in relative abundance will be calculated.

Usage

abundance_change(
  df,
  time.var,
  species.var,
  abundance.var,
  replicate.var = NULL,
  reference.time = NULL
)

Arguments

df

A data frame containing time, species, and abundance columns and an optional columns of replicates.

time.var

The name of the time column.

species.var

The name of the species column.

abundance.var

The name of the abundance column.

replicate.var

The name of the optional replicate column. If specified, replicate must be unique within the dataset and cannot be nested within treatments or blocks.

reference.time

The name of the optional time point that all other time points should be compared to (e.g. the first year of data). If not specified, each comparison is between consecutive time points (the first and second year, second and third year, etc.)

Value

The `abundance_change()` function returns a data frame with a subset of the following columns: - **replicate.var**: A column with the specified `replicate.var`, if it is specified. - **time.var**: A column with the specified `time.var` and a second column, with '2' appended to the name. Time is subtracted from time2. - **species.var**: A column with the specified `species.var`. - **change**: A numeric column of the change in abundance between time points. A positive value occurs when a species increases in abundance over time, and a negative value when a species decreases in abundance over time.#' @references Avolio et al. Submitted

Examples

data(pplots)
# Without replicates
df <- subset(pplots, plot == 25)
abundance_change(df = df,
                 species.var = "species",
                 abundance.var = "relative_cover",
                 time.var = "year")
#>     year year2                    species       change
#> 2   2002  2003          amorpha canescens -0.002123142
#> 23  2002  2003        andropogon gerardii -0.082504430
#> 28  2003  2004        andropogon gerardii  0.207558855
#> 29  2004  2005        andropogon gerardii -0.304927630
#> 34  2004  2005       andropogon scoparius  0.078196997
#> 44  2002  2003       andropogon scoparius  0.062022085
#> 45  2003  2004       andropogon scoparius -0.126299880
#> 50  2003  2004        antennaria neglecta  0.002114165
#> 55  2004  2005        antennaria neglecta -0.000948664
#> 66  2002  2003            aster ericoides -0.007643615
#> 71  2003  2004            aster ericoides  0.018097734
#> 76  2004  2005            aster ericoides -0.010082940
#> 87  2002  2003     bouteloua curtipendula -0.015529356
#> 92  2003  2004     bouteloua curtipendula  0.006982922
#> 93  2004  2005     bouteloua curtipendula  0.017618041
#> 98  2004  2005           carex heliophila  0.025044723
#> 108 2002  2003           carex heliophila -0.004928777
#> 109 2003  2004           carex heliophila  0.013349527
#> 114 2003  2004               carex meadii  0.001232635
#> 119 2004  2005               carex meadii  0.064671763
#> 125 2002  2003               carex meadii -0.016166450
#> 135 2003  2004          conyza canadensis  0.002114165
#> 140 2004  2005          conyza canadensis -0.002114165
#> 157 2004  2005          cyperus lupulinus  0.002331002
#> 162 2004  2005              dalea candida  0.001816013
#> 172 2002  2003              dalea candida  0.022140908
#> 173 2003  2004              dalea candida -0.022167840
#> 178 2003  2004             dalea purpurea  0.004916978
#> 183 2004  2005             dalea purpurea -0.006342495
#> 189 2002  2003             dalea purpurea  0.001425517
#> 194 2002  2003 dichanthelium oligosanthes -0.007734412
#> 199 2003  2004 dichanthelium oligosanthes -0.002899254
#> 204 2004  2005 dichanthelium oligosanthes  0.000433675
#> 210 2002  2003     eragrostis spectabilis  0.010008882
#> 215 2003  2004     eragrostis spectabilis -0.007912672
#> 220 2004  2005     eragrostis spectabilis  0.025126036
#> 231 2002  2003        koeleria pyramidata -0.006369427
#> 242 2004  2005       kuhnia eupatorioides -0.002412317
#> 252 2002  2003       kuhnia eupatorioides  0.003609190
#> 253 2003  2004       kuhnia eupatorioides  0.000592208
#> 258 2003  2004             linum sulcatum  0.012684989
#> 263 2004  2005             linum sulcatum -0.012684989
#> 269 2002  2003             linum sulcatum -0.004246285
#> 274 2002  2003            physalis pumila -0.001395252
#> 279 2003  2004            physalis pumila -0.000736868
#> 284 2004  2005            physalis pumila -0.000948664
#> 300 2003  2004       plantago rhodosperma  0.002114165
#> 301 2004  2005       plantago rhodosperma -0.002114165
#> 316 2002  2003              poa pratensis -0.084925690
#> 322 2003  2004            ruellia humilis  0.002114165
#> 327 2004  2005            ruellia humilis -0.002114165
#> 338 2002  2003         senecio plattensis -0.002123142
#> 364 2003  2004     sisyrinchium campestre  0.002114165
#> 365 2004  2005     sisyrinchium campestre  0.000216837
#> 370 2004  2005     solidago missouriensis  0.040467285
#> 380 2002  2003     solidago missouriensis  0.002365268
#> 381 2003  2004     solidago missouriensis  0.008070896
#> 386 2003  2004         sorghastrum nutans -0.122615537
#> 391 2004  2005         sorghastrum nutans  0.088767822
#> 397 2002  2003         sorghastrum nutans  0.132692607
#> 402 2002  2003          viola rafinesquii  0.001425517
#> 407 2003  2004          viola rafinesquii -0.001425517

# With replicates
df <- subset(pplots, year < 2004 & plot %in% c(6, 25, 32))
abundance_change(df = df,
                 species.var = "species",
                 abundance.var = "relative_cover",
                 replicate.var = "plot",
                 time.var = "year")
#>    year year2 plot                    species       change
#> 1  2002  2003    6      ambrosia psilostachya  0.001881712
#> 2  2002  2003    6        andropogon gerardii -0.038493392
#> 3  2002  2003    6       andropogon scoparius -0.062873948
#> 4  2002  2003    6      asclepias stenophylla  0.002890173
#> 5  2002  2003    6     asclepias verticillata -0.002453548
#> 6  2002  2003    6            aster ericoides  0.001777485
#> 7  2002  2003    6     bouteloua curtipendula  0.058775310
#> 8  2002  2003    6           carex heliophila -0.035087719
#> 9  2002  2003    6               carex meadii  0.000873249
#> 10 2002  2003    6              dalea candida  0.014315655
#> 11 2002  2003    6             dalea purpurea  0.001445087
#> 12 2002  2003    6 dichanthelium oligosanthes  0.011960699
#> 13 2002  2003    6              draba reptans -0.001949318
#> 14 2002  2003    6        koeleria pyramidata -0.002084530
#> 15 2002  2003    6       kuhnia eupatorioides  0.026380579
#> 16 2002  2003    6             linum sulcatum -0.009746589
#> 17 2002  2003    6              poa pratensis  0.001746498
#> 18 2002  2003    6       ratibida columnifera -0.003898635
#> 19 2002  2003    6            ruellia humilis -0.002453548
#> 20 2002  2003    6         senecio plattensis -0.002453548
#> 21 2002  2003    6     sisyrinchium campestre -0.001949318
#> 22 2002  2003    6     solidago missouriensis -0.003898635
#> 23 2002  2003    6         sorghastrum nutans  0.053363982
#> 24 2002  2003    6           sporobolus asper -0.006118379
#> 25 2002  2003    6       triodanis perfoliata -0.001949318
#> 26 2002  2003   25          amorpha canescens -0.002123142
#> 27 2002  2003   25        andropogon gerardii -0.082504430
#> 28 2002  2003   25       andropogon scoparius  0.062022085
#> 29 2002  2003   25            aster ericoides -0.007643615
#> 30 2002  2003   25     bouteloua curtipendula -0.015529356
#> 31 2002  2003   25           carex heliophila -0.004928777
#> 32 2002  2003   25               carex meadii -0.016166450
#> 33 2002  2003   25              dalea candida  0.022140908
#> 34 2002  2003   25             dalea purpurea  0.001425517
#> 35 2002  2003   25 dichanthelium oligosanthes -0.007734412
#> 36 2002  2003   25     eragrostis spectabilis  0.010008882
#> 37 2002  2003   25        koeleria pyramidata -0.006369427
#> 38 2002  2003   25       kuhnia eupatorioides  0.003609190
#> 39 2002  2003   25             linum sulcatum -0.004246285
#> 40 2002  2003   25            physalis pumila -0.001395252
#> 41 2002  2003   25              poa pratensis -0.084925690
#> 42 2002  2003   25         senecio plattensis -0.002123142
#> 43 2002  2003   25     solidago missouriensis  0.002365268
#> 44 2002  2003   25         sorghastrum nutans  0.132692607
#> 45 2002  2003   25          viola rafinesquii  0.001425517
#> 46 2002  2003   32      ambrosia psilostachya -0.000977422
#> 47 2002  2003   32          amorpha canescens  0.005434900
#> 48 2002  2003   32        andropogon gerardii  0.343172004
#> 49 2002  2003   32       andropogon scoparius -0.181922336
#> 50 2002  2003   32        antennaria neglecta -0.002534854
#> 51 2002  2003   32         asclepias tuberosa  0.011299435
#> 52 2002  2003   32            aster ericoides -0.024510752
#> 53 2002  2003   32        aster oblongifolius  0.015065913
#> 54 2002  2003   32     bouteloua curtipendula -0.076224642
#> 55 2002  2003   32           carex heliophila  0.003118444
#> 56 2002  2003   32               carex meadii  0.040926439
#> 57 2002  2003   32       delphinium virescens  0.003766478
#> 58 2002  2003   32   dichanthelium acuminatum -0.006337136
#> 59 2002  2003   32 dichanthelium oligosanthes  0.011664626
#> 60 2002  2003   32     eragrostis spectabilis -0.003802281
#> 61 2002  2003   32          euphorbia serpens  0.001883239
#> 62 2002  2003   32       kuhnia eupatorioides  0.003079060
#> 63 2002  2003   32             linum sulcatum -0.003802281
#> 64 2002  2003   32          panicum capillare  0.005649718
#> 65 2002  2003   32              poa pratensis -0.008291980
#> 66 2002  2003   32            ruellia humilis  0.001811633
#> 67 2002  2003   32         senecio plattensis  0.000615812
#> 68 2002  2003   32     solidago missouriensis  0.001450023
#> 69 2002  2003   32         sorghastrum nutans -0.130867221
#> 70 2002  2003   32           sporobolus asper -0.009666817
                 
# With reference year
df <- subset(pplots, year < 2005 & plot %in% c(6, 25, 32))
abundance_change(df = df,
                 species.var = "species",
                 abundance.var = "relative_cover",
                 replicate.var = "plot",
                 time.var = "year",
                 reference.time = 2002)
#>     year year2 plot                    species       change
#> 1   2002  2003    6      ambrosia psilostachya  0.001881712
#> 2   2002  2004    6      ambrosia psilostachya  0.002812774
#> 3   2002  2003    6        andropogon gerardii -0.038493392
#> 4   2002  2004    6        andropogon gerardii -0.161054202
#> 5   2002  2003    6       andropogon scoparius -0.062873948
#> 6   2002  2004    6       andropogon scoparius  0.131873308
#> 7   2002  2004    6      asclepias stenophylla  0.001677852
#> 8   2002  2003    6      asclepias stenophylla  0.002890173
#> 9   2002  2004    6     asclepias verticillata -0.002220783
#> 10  2002  2003    6     asclepias verticillata -0.002453548
#> 11  2002  2003    6            aster ericoides  0.001777485
#> 12  2002  2004    6            aster ericoides -0.019345998
#> 13  2002  2003    6     bouteloua curtipendula  0.058775310
#> 14  2002  2004    6     bouteloua curtipendula -0.040935673
#> 15  2002  2004    6           carex heliophila  0.011892147
#> 16  2002  2003    6           carex heliophila -0.035087719
#> 17  2002  2004    6               carex meadii  0.007303400
#> 18  2002  2003    6               carex meadii  0.000873249
#> 20  2002  2004    6          conyza canadensis  0.005033557
#> 21  2002  2003    6              dalea candida  0.014315655
#> 22  2002  2004    6              dalea candida  0.005082617
#> 24  2002  2003    6             dalea purpurea  0.001445087
#> 25  2002  2004    6 dichanthelium oligosanthes  0.021736856
#> 26  2002  2003    6 dichanthelium oligosanthes  0.011960699
#> 27  2002  2003    6              draba reptans -0.001949318
#> 28  2002  2004    6              draba reptans -0.001949318
#> 30  2002  2004    6         erigeron strigosus  0.001677852
#> 31  2002  2003    6        koeleria pyramidata -0.002084530
#> 32  2002  2004    6        koeleria pyramidata  0.029978937
#> 33  2002  2004    6       kuhnia eupatorioides -0.009746589
#> 34  2002  2003    6       kuhnia eupatorioides  0.026380579
#> 35  2002  2004    6             linum sulcatum  0.010387639
#> 36  2002  2003    6             linum sulcatum -0.009746589
#> 37  2002  2003    6              poa pratensis  0.001746498
#> 38  2002  2004    6              poa pratensis -0.007205280
#> 39  2002  2003    6       ratibida columnifera -0.003898635
#> 40  2002  2004    6       ratibida columnifera -0.003898635
#> 41  2002  2004    6            ruellia humilis  0.002812774
#> 42  2002  2003    6            ruellia humilis -0.002453548
#> 43  2002  2004    6         senecio plattensis -0.003898635
#> 44  2002  2003    6         senecio plattensis -0.002453548
#> 46  2002  2004    6          silene antirrhina  0.010067114
#> 47  2002  2003    6     sisyrinchium campestre -0.001949318
#> 48  2002  2004    6     sisyrinchium campestre -0.001949318
#> 49  2002  2004    6     solidago missouriensis  0.012879888
#> 50  2002  2003    6     solidago missouriensis -0.003898635
#> 51  2002  2004    6         sorghastrum nutans  0.004686867
#> 52  2002  2003    6         sorghastrum nutans  0.053363982
#> 53  2002  2003    6           sporobolus asper -0.006118379
#> 54  2002  2004    6           sporobolus asper -0.020850504
#> 55  2002  2003    6       triodanis perfoliata -0.001949318
#> 56  2002  2004    6       triodanis perfoliata  0.009795648
#> 58  2002  2004    6          viola rafinesquii  0.003355705
#> 59  2002  2003   25          amorpha canescens -0.002123142
#> 60  2002  2004   25          amorpha canescens -0.002123142
#> 61  2002  2003   25        andropogon gerardii -0.082504430
#> 62  2002  2004   25        andropogon gerardii  0.125054425
#> 63  2002  2003   25       andropogon scoparius  0.062022085
#> 64  2002  2004   25       andropogon scoparius -0.064277795
#> 66  2002  2004   25        antennaria neglecta  0.002114165
#> 67  2002  2003   25            aster ericoides -0.007643615
#> 68  2002  2004   25            aster ericoides  0.010454119
#> 69  2002  2003   25     bouteloua curtipendula -0.015529356
#> 70  2002  2004   25     bouteloua curtipendula -0.008546434
#> 71  2002  2003   25           carex heliophila -0.004928777
#> 72  2002  2004   25           carex heliophila  0.008420750
#> 73  2002  2003   25               carex meadii -0.016166450
#> 74  2002  2004   25               carex meadii -0.014933815
#> 76  2002  2004   25          conyza canadensis  0.002114165
#> 77  2002  2003   25              dalea candida  0.022140908
#> 78  2002  2004   25              dalea candida -0.000026932
#> 79  2002  2003   25             dalea purpurea  0.001425517
#> 80  2002  2004   25             dalea purpurea  0.006342495
#> 81  2002  2003   25 dichanthelium oligosanthes -0.007734412
#> 82  2002  2004   25 dichanthelium oligosanthes -0.010633666
#> 83  2002  2004   25     eragrostis spectabilis  0.002096210
#> 84  2002  2003   25     eragrostis spectabilis  0.010008882
#> 85  2002  2003   25        koeleria pyramidata -0.006369427
#> 86  2002  2004   25        koeleria pyramidata -0.006369427
#> 87  2002  2003   25       kuhnia eupatorioides  0.003609190
#> 88  2002  2004   25       kuhnia eupatorioides  0.004201398
#> 89  2002  2003   25             linum sulcatum -0.004246285
#> 90  2002  2004   25             linum sulcatum  0.008438704
#> 91  2002  2003   25            physalis pumila -0.001395252
#> 92  2002  2004   25            physalis pumila -0.002132120
#> 94  2002  2004   25       plantago rhodosperma  0.002114165
#> 95  2002  2003   25              poa pratensis -0.084925690
#> 96  2002  2004   25              poa pratensis -0.084925690
#> 98  2002  2004   25            ruellia humilis  0.002114165
#> 99  2002  2003   25         senecio plattensis -0.002123142
#> 100 2002  2004   25         senecio plattensis -0.002123142
#> 102 2002  2004   25     sisyrinchium campestre  0.002114165
#> 103 2002  2003   25     solidago missouriensis  0.002365268
#> 104 2002  2004   25     solidago missouriensis  0.010436164
#> 105 2002  2003   25         sorghastrum nutans  0.132692607
#> 106 2002  2004   25         sorghastrum nutans  0.010077070
#> 107 2002  2003   25          viola rafinesquii  0.001425517
#> 109 2002  2003   32      ambrosia psilostachya -0.000977422
#> 110 2002  2004   32      ambrosia psilostachya -0.003802281
#> 111 2002  2003   32          amorpha canescens  0.005434900
#> 112 2002  2004   32          amorpha canescens -0.019792540
#> 113 2002  2004   32        andropogon gerardii  0.019892096
#> 114 2002  2003   32        andropogon gerardii  0.343172004
#> 115 2002  2004   32       andropogon scoparius -0.072216543
#> 116 2002  2003   32       andropogon scoparius -0.181922336
#> 117 2002  2004   32        antennaria neglecta -0.002534854
#> 118 2002  2003   32        antennaria neglecta -0.002534854
#> 119 2002  2003   32         asclepias tuberosa  0.011299435
#> 121 2002  2004   32            aster ericoides -0.004753809
#> 122 2002  2003   32            aster ericoides -0.024510752
#> 123 2002  2004   32        aster oblongifolius  0.012084592
#> 124 2002  2003   32        aster oblongifolius  0.015065913
#> 125 2002  2004   32     bouteloua curtipendula -0.078440720
#> 126 2002  2003   32     bouteloua curtipendula -0.076224642
#> 127 2002  2003   32           carex heliophila  0.003118444
#> 128 2002  2004   32           carex heliophila -0.015850497
#> 129 2002  2004   32               carex meadii  0.053739293
#> 130 2002  2003   32               carex meadii  0.040926439
#> 131 2002  2004   32          conyza canadensis  0.004531722
#> 134 2002  2003   32       delphinium virescens  0.003766478
#> 135 2002  2003   32   dichanthelium acuminatum -0.006337136
#> 136 2002  2004   32   dichanthelium acuminatum  0.005747456
#> 137 2002  2003   32 dichanthelium oligosanthes  0.011664626
#> 138 2002  2004   32 dichanthelium oligosanthes  0.034050138
#> 139 2002  2004   32     eragrostis spectabilis -0.003802281
#> 140 2002  2003   32     eragrostis spectabilis -0.003802281
#> 142 2002  2003   32          euphorbia serpens  0.001883239
#> 143 2002  2004   32       kuhnia eupatorioides  0.007258030
#> 144 2002  2003   32       kuhnia eupatorioides  0.003079060
#> 145 2002  2003   32             linum sulcatum -0.003802281
#> 146 2002  2004   32             linum sulcatum -0.003802281
#> 148 2002  2003   32          panicum capillare  0.005649718
#> 149 2002  2004   32              poa pratensis  0.005695764
#> 150 2002  2003   32              poa pratensis -0.008291980
#> 151 2002  2004   32            ruellia humilis -0.007604563
#> 152 2002  2003   32            ruellia humilis  0.001811633
#> 153 2002  2003   32         senecio plattensis  0.000615812
#> 154 2002  2004   32         senecio plattensis -0.001267427
#> 155 2002  2004   32     solidago missouriensis -0.000589679
#> 156 2002  2003   32     solidago missouriensis  0.001450023
#> 157 2002  2004   32         sorghastrum nutans  0.069373447
#> 158 2002  2003   32         sorghastrum nutans -0.130867221
#> 159 2002  2004   32           sporobolus asper -0.020573674
#> 160 2002  2003   32           sporobolus asper -0.009666817
#> 162 2002  2004   32       triodanis perfoliata  0.006042296
#> 164 2002  2004   32          viola rafinesquii  0.016616314