partitionBEFsp (version 1.0)

partitionBEFsp: partitionBEFsp: A package for calculating the Loreau & Hector 2001 BEF partition.

Description

The partitionBEFsp (or "partitioning Biodiversity-Ecosystem Functioning as sample-level and population-level estimates" package) is a collection of functions that can be used to estimate selection and complementarity effects, sensu Loreau & Hector 2001 (Nature 412:72-76), even in cases where data are only available for a random subset of species (i.e. incomplete sample-level data). A full derivation and explanation of the statistical corrections used here is available in Clark et al. 2019, Estimating Complementarity and Selection Effects from an Incomplete Sample of Species.

Examples

# NOT RUN {
#Monoculture biomasses for 57 species
M<-c(57.57, 2.33, 306.25, 172.42, 351.48, 280.15, 216.93,
     1.30, 397.73, 185.57, 19.81, 162.45, 36.23, 42.48,
     3.16, 250.12, 5.30, 58.06, 172.93, 210.50, 253.78,
     15.96, 218.62, 282.00, 342.73, 242.18, 49.39, 100.00,
     112.20, 181.50, 61.98, 428.82, 911.55, 80.60, 206.75,
     108.25, 58.45, 154.55, 114.58, 144.38, 273.98, 25.41,
     148.82, 48.27, 35.62, 168.45, 157.98, 100.47, 31.12,
     9.86, 247.57, 182.32, 16.20, 251.30, 118.73, 137.65,
     149.93)

#Polyculture biomasses for a community of 57 species
P<-c(31.82, 0.06, 6.93, 6.75, 0.00, 0.11, 0.00,
     10.95, 0.19, 0.58, 0.01, 0.52, 21.72, 16.20,
     0.00, 0.09, 3.42, 0.00, 0.02, 3.18, 8.86,
     0.03, 0.02, 0.00, 10.14, 8.93, 4.53, 0.00,
     0.00, 0.02, 8.80, 0.31, 21.47, 0.34, 14.52,
     0.15, 0.00, 17.17, 66.55, 1.65, 0.44, 0.17,
     7.11, 0.45, 5.37, 7.66, 4.37, 0.00, 120.08,
     144.61, 0.00, 0.00, 0.00, 8.33, 93.18, 0.58,
     1.77)


#calculate DRY
DRY<-calculate_DRY(M=M, P=P, Q=length(M))

####################################
# Example 1: Classic partition
####################################

#calculate classic partition for full community
classic_partition(DRY=DRY, M=M)

#note that sum of partition equals the change in yield,
#but only if sample-size corrected covariance isn't used
N<-length(M)
cp_F<-classic_partition(DRY=DRY, M=M, uncorrected_cov = FALSE)
cp_T<-classic_partition(DRY=DRY, M=M, uncorrected_cov = TRUE)
cp_C<-classic_partition(DRY=DRY, M=M, uncorrected_cov = "COMP")

sum(P-M/N) #observed - expected yield
cp_F$S+cp_F$C #default
cp_T$S+cp_T$C #non-sample-size corrected
cp_C$S+cp_C$C #compromise

#also note that compromise only perfectly equals change in yield
#if Q = N (i.e. if the entire community is sampled)

sum(unlist(classic_partition(DRY=DRY, M=M, uncorrected_cov = "COMP", N=length(DRY), Q=N)))
sum(unlist(classic_partition(DRY=DRY, M=M, uncorrected_cov = "COMP", N=length(DRY), Q=N*2)))


####################################
# Example 2: Estimate population-level statistics
####################################
#estimate population-level partition for full community using only 30 species
set.seed(25123)
smp<-sample(30)
DRY_sample<-DRY[smp]
M_sample<-M[smp]
sample_to_population_partition(DRY=DRY_sample, M=M_sample, N=length(M_sample), Q=57)
#note - SP and CP are relatively close to the classic partition for the full community,
#whereas SS and CS are not.

#Repeat procedure for samples of between 2 and 57 species:
N_sample<-2:57
SP_est<-numeric(length(N_sample))
CP_est<-numeric(length(N_sample))

for(i in 1:length(N_sample)) {
  #sample N random species
  smp<-sample(1:57, N_sample[i])

  pop_est<-sample_to_population_partition(DRY=DRY[smp], M=M[smp], N=N_sample[i], Q=57)
  SP_est[i]<-pop_est$SP
  CP_est[i]<-pop_est$CP
}

#Plot estimates vs. true value (dotted line)
plot(N_sample, SP_est, type="b"); abline(h=classic_partition(DRY=DRY, M=M)$S, lty=3, col=2)
plot(N_sample, CP_est, type="b"); abline(h=classic_partition(DRY=DRY, M=M)$C, lty=3, col=2)
#note - estimates are noisy, but converge to the true value as N approaches Q.


####################################
# Example 3: Estimate sample-level statistics
####################################

#estimate expected value of sample-level statistics for a random sample of 30 species
#based on the full population of Q species
population_to_sample_partition(DRY=DRY, M=M, N=30, Q=57)

#Repeat procedure for samples of between 2 and 57 species:
N_sample<-2:57
SS_est<-numeric(length(N_sample))
CS_est<-numeric(length(N_sample))

for(i in 1:length(N_sample)) {
  pop_est<-population_to_sample_partition(DRY=DRY, M=M, N=N_sample[i], Q=57)
  SS_est[i]<-pop_est$SS
  CS_est[i]<-pop_est$CS
}

#Plot estimates vs. true value (dotted line)
plot(N_sample, SS_est/N_sample, type="b")
abline(h=classic_partition(DRY=DRY, M=M)$S/57, lty=3, col=2)
#note - expected value of SS/N = SP/Q for all N
plot(N_sample, CS_est/N_sample, type="b")
abline(h=classic_partition(DRY=DRY, M=M)$C/57, lty=3, col=2)
#note - expected value of CS/N is a biased estimate of SP/Q, especially for small N


####################################
# Example 4: Estimate confidence intervals
####################################
smp_ci<-sample_to_population_partition(DRY=DRY, M=M, Q=57, nboot=1000)
smp_ci$confint$bootdat_summary
# }