diff --git a/WombatPopModel.R b/WombatPopModel.R new file mode 100644 index 0000000..1a0a1bd --- /dev/null +++ b/WombatPopModel.R @@ -0,0 +1,319 @@ +########################################################################################################################################## +## common wombat (Vombatus ursinus) demographic model +## +## Corey Bradshaw +## corey.bradshaw@flinders.edu.au +## Flinders University, September 2021 +########################################################################################################################################## + +## functions +# beta distribution shape parameter estimator function +estBetaParams <- function(mu, var) { + alpha <- ((1 - mu) / var - 1 / mu) * mu ^ 2 + beta <- alpha * (1 / mu - 1) + return(params = list(alpha = alpha, beta = beta)) +} + +AICc <- function(...) { + models <- list(...) + num.mod <- length(models) + AICcs <- numeric(num.mod) + ns <- numeric(num.mod) + ks <- numeric(num.mod) + AICc.vec <- rep(0,num.mod) + for (i in 1:num.mod) { + if (length(models[[i]]$df.residual) == 0) n <- models[[i]]$dims$N else n <- length(models[[i]]$residuals) + if (length(models[[i]]$df.residual) == 0) k <- sum(models[[i]]$dims$ncol) else k <- (length(models[[i]]$coeff))+1 + AICcs[i] <- (-2*logLik(models[[i]])) + ((2*k*n)/(n-k-1)) + ns[i] <- n + ks[i] <- k + AICc.vec[i] <- AICcs[i] + } + return(AICc.vec) +} + +delta.AIC <- function(x) x - min(x) ## where x is a vector of AIC +weight.AIC <- function(x) (exp(-0.5*x))/sum(exp(-0.5*x)) ## Where x is a vector of dAIC +ch.dev <- function(x) ((( as.numeric(x$null.deviance) - as.numeric(x$deviance) )/ as.numeric(x$null.deviance))*100) ## % change in deviance, where x is glm object + +linreg.ER <- function(x,y) { # where x and y are vectors of the same length; calls AICc, delta.AIC, weight.AIC functions + fit.full <- lm(y ~ x); fit.null <- lm(y ~ 1) + AIC.vec <- c(AICc(fit.full),AICc(fit.null)) + dAIC.vec <- delta.AIC(AIC.vec); wAIC.vec <- weight.AIC(dAIC.vec) + ER <- wAIC.vec[1]/wAIC.vec[2] + r.sq.adj <- as.numeric(summary(fit.full)[9]) + return(c(ER,r.sq.adj)) +} + +## source +source("matrixOperators.r") + + +############################## +## VOMBATUS (ursinus) (VU) +## sources: Roger et al. 2011 Popul Ecol 53:215-227 + +# mass +VU.mass <- 25 # Vombatus ursinus (Saran et al. 2011 Pacific Conservation Biology 17:310-319) + +## predicted rm (from Henneman 1983 Oecologia 56:104-108) +## log10rm = 0.6914 - 0.2622*log10m (mass in g) +VU.rm.pred <- 10^(0.6914 - (0.2622*log10(VU.mass*1000))) +VU.lm.pred <- exp(VU.rm.pred) + +## theoretical population density for mammalian herbivores based on body size (Damuth 1981; Freeland 1990) +## log10D = 4.196 − 0.74*(log10m) +VU.D.pred <- (10^(4.196 - (0.74*log10(VU.mass*1000))))/2 # divided by 2 for females only +VU.D.pred # animals/km2 + +## max age +## non-volant birds & mammals (Healy K et al. 2014 PRSB) +## log10ls = 0.89 + 0.13log10m (mass in grams; ls = years) +VU.age.max <- round(10^(0.89 + (0.13*log10(VU.mass*1000))), 0) +VU.age.max <- 26 # reset based on McIlroy 2008 + +## age vector +VU.age.vec <- 0:VU.age.max + +## fertility +## total fecundity from Allainé et al. 1987 (Oecologia) +## lnF = 2.719 - 0.211lnM (all mammals) +VU.F.pred <- exp(2.719 - (0.211*log(VU.mass*1000)))/2 # divided by 2 for females +VU.F.pred <- 1/2/2 # inter-birth interval of 2 years / 2 for daughters only (McIlroy 1995) + +## age at primiparity +## lnalpha = 0.214 + 0.263*lnM (https://dx.doi.org/10.1093%2Fgerona%2F62.2.149) +VU.alpha <- ceiling(exp(-1.34 + (0.214*log(VU.mass*1000)))) +VU.alpha <- 2 # reset according to Roger et al. (2011) + +## define m function with age +## pouch young per year +VU.pypy <- 0.5 + +## proportion of females breeding each year +VU.pfbr <- 0.84 + +## proportion young that are female +VU.sr <- 0.5 + +## m vector +VU.m.vec <- c(0, 0.3*VU.F.pred, 0.9*VU.F.pred, rep(VU.F.pred, 24)) +VU.m.sd.vec <- 0.05*VU.m.vec +plot(VU.age.vec, VU.m.vec, type="b", pch=19, xlab="age (yrs)", ylab="m") + +# fit sigmoidal function +# logistic power function y = a / (1+(x/b)^c) +VU.m.dat <- data.frame(VU.age.vec, VU.m.vec) +param.init <- c(0.2, 2, -3) +VU.fit.logp <- nls(VU.m.vec ~ a / (1+(VU.age.vec/b)^c), + data = VU.m.dat, + algorithm = "port", + start = c(a = param.init[1], b = param.init[2], c = param.init[3]), + trace = TRUE, + nls.control(maxiter = 1000, tol = 1e-05, minFactor = 1/1024)) +VU.fit.logp.summ <- summary(VU.fit.logp) +plot(VU.age.vec, VU.m.vec, type="b", pch=19, xlab="age (yrs)", ylab="m") +VU.age.vec.cont <- seq(0,max(VU.age.vec),1) +VU.pred.p.m <- coef(VU.fit.logp)[1] / (1+(VU.age.vec.cont/coef(VU.fit.logp)[2])^coef(VU.fit.logp)[3]) +VU.pred.p.mm <- ifelse(VU.pred.p.m > 1, 1, VU.pred.p.m) +VU.pred.p.mm[2] <- 0 +lines(VU.age.vec.cont, VU.pred.p.mm,lty=2,lwd=3,col="red") + +## survival +## mean adult survival (McCarthy et al. 2008 Am Nat) +## ln{-ln[s(t)]} = ln(a) + bln(M) + ln (t) +ln.a.s <- -0.5; b.s <- -0.25 +VU.s.tran <- ln.a.s + b.s*log(VU.mass*1000) + log(1) +VU.s.ad.yr <- exp(-exp(VU.s.tran)) + +# Siler hazard h(x) (Gurven et al. 2007) +a1 <- 1 - (1.05*VU.s.ad.yr) # initial infant mortality rate (also known as αt) +b1 <- 3.1 # rate of mortality decline (also known as bt) +a2 <- 1 - VU.s.ad.yr # age-independent mortality (exogenous mortality due to environment); also known as ct +a3 <- 0.1e-04 # initial adult mortality rate (also known as βt) +b3 <- 0.02 # rate of mortality increase +longev <- VU.age.max +x <- seq(0,longev,1) # age vector +h.x <- a1 * exp(-b1*x) + a2 + a3 * exp(b3 * x) # Siler's hazard model +plot(x,h.x,pch=19,type="l") +plot(x,log(h.x),pch=19,type="l") +l.x <- exp((-a1/b1) * (1 - exp(-b1*x))) * exp(-a2 * x) * exp(a3/b3 * (1 - exp(b3 * x))) # Siler's survival (proportion surviving) model +init.pop <- 10000 +lx <- round(init.pop*l.x,0) +len.lx <- length(lx) +dx <- lx[1:(len.lx-1)]-lx[2:len.lx] +qx <- dx/lx[1:(length(lx)-1)] +VU.Sx <- c(0.99*VU.s.ad.yr, 1 - qx) +plot(x, VU.Sx, pch=19, type="l", xlab="age (years)", ylab="Sx") +VU.s.sd.vec <- 0.05*VU.Sx + +## create matrix +VU.popmat <- matrix(data = 0, nrow=VU.age.max+1, ncol=VU.age.max+1) +diag(VU.popmat[2:(VU.age.max+1),]) <- VU.Sx[-(VU.age.max+1)] +VU.popmat[VU.age.max+1,VU.age.max+1] <- 0 +VU.popmat[1,] <- VU.pred.p.mm +colnames(VU.popmat) <- c(0:VU.age.max) +rownames(VU.popmat) <- c(0:VU.age.max) +VU.popmat.orig <- VU.popmat ## save original matrix + +## matrix properties +max.lambda(VU.popmat.orig) ## 1-yr lambda +VU.lm.pred +max.r(VU.popmat.orig) # rate of population change, 1-yr +VU.ssd <- stable.stage.dist(VU.popmat.orig) ## stable stage distribution +plot(VU.age.vec, VU.ssd, type="l", pch=19, xlab="age (yrs)", ylab="ssd") +R.val(VU.popmat.orig, VU.age.max) # reproductive value +VU.gen.l <- G.val(VU.popmat.orig, VU.age.max) # mean generation length + +## initial population vector +area <- 500*500 # km × km +VU.pop.found <- round(area*VU.D.pred, 0) # founding population size (estimated density * 100 × 100 km region [10,000 km2]) +VU.init.vec <- VU.ssd * VU.pop.found + +################# +## project +## set time limit for projection in 1-yr increments +yr.st <- 1 +#************************ +yr.end <- round(40*VU.gen.l, 0) # set projection end date +#************************ +t <- (yr.end - yr.st) + +VU.tot.F <- sum(VU.popmat.orig[1,]) +VU.popmat <- VU.popmat.orig +yr.vec <- seq(yr.st,yr.end) + +## set population storage matrices +VU.n.mat <- matrix(0, nrow=VU.age.max+1,ncol=(t+1)) +VU.n.mat[,1] <- VU.init.vec + +## set up projection loop +for (i in 1:t) { + VU.n.mat[,i+1] <- VU.popmat %*% VU.n.mat[,i] +} + +VU.n.pred <- colSums(VU.n.mat) +yrs <- seq(yr.st, yr.end, 1) +plot(yrs, log10(VU.n.pred),type="l",lty=2,pch=19,xlab="year",ylab="log10 N") + +# compensatory density feedback +VU.K.max <- 1*VU.pop.found +VU.K.vec <- c(1, VU.K.max/2, 0.75*VU.K.max, VU.K.max) +VU.red.vec <- c(1,0.985,0.951,0.873) +plot(VU.K.vec, VU.red.vec,pch=19,type="b") +VU.Kred.dat <- data.frame(VU.K.vec, VU.red.vec) + +# logistic power function a/(1+(x/b)^c) +VU.param.init <- c(1, 2*VU.K.max, 2) +VU.fit.lp <- nls(VU.red.vec ~ a/(1+(VU.K.vec/b)^c), + data = VU.Kred.dat, + algorithm = "port", + start = c(a = VU.param.init[1], b = VU.param.init[2], c = VU.param.init[3]), + trace = TRUE, + nls.control(maxiter = 1000, tol = 1e-05, minFactor = 1/1024)) +VU.fit.lp.summ <- summary(VU.fit.lp) +plot(VU.K.vec, VU.red.vec, pch=19,xlab="N",ylab="reduction factor") +VU.K.vec.cont <- seq(1,2*VU.pop.found,1) +VU.pred.lp.fx <- coef(VU.fit.lp)[1]/(1+(VU.K.vec.cont/coef(VU.fit.lp)[2])^coef(VU.fit.lp)[3]) +lines(VU.K.vec.cont, VU.pred.lp.fx, lty=3,lwd=3,col="red") + +VU.a.lp <- coef(VU.fit.lp)[1] +VU.b.lp <- coef(VU.fit.lp)[2] +VU.c.lp <- coef(VU.fit.lp)[3] + +## compensatory density-feedback deterministic model +## set population storage matrices +VU.n.mat <- matrix(0, nrow=VU.age.max+1, ncol=(t+1)) +VU.n.mat[,1] <- VU.init.vec +VU.popmat <- VU.popmat.orig + +## set up projection loop +for (i in 1:t) { + VU.totN.i <- sum(VU.n.mat[,i]) + VU.pred.red <- as.numeric(VU.a.lp/(1+(VU.totN.i/VU.b.lp)^VU.c.lp)) + diag(VU.popmat[2:(VU.age.max+1),]) <- (VU.Sx[-(VU.age.max+1)])*VU.pred.red + VU.popmat[VU.age.max+1,VU.age.max+1] <- 0 + VU.popmat[1,] <- VU.pred.p.mm + VU.n.mat[,i+1] <- VU.popmat %*% VU.n.mat[,i] +} + +VU.n.pred <- colSums(VU.n.mat) +plot(yrs, VU.n.pred, type="l",lty=2,pch=19,xlab="year",ylab="N") +abline(h=VU.pop.found, lty=2, col="red", lwd=2) + +## stochatic projection with density feedback +## set storage matrices & vectors +iter <- 100 +itdiv <- iter/10 + +VU.n.sums.mat <- matrix(data=NA, nrow=iter, ncol=(t+1)) +VU.s.arr <- VU.m.arr <- array(data=NA, dim=c(t+1, VU.age.max+1, iter)) + +for (e in 1:iter) { + VU.popmat <- VU.popmat.orig + + VU.n.mat <- matrix(0, nrow=VU.age.max+1,ncol=(t+1)) + VU.n.mat[,1] <- VU.init.vec + + for (i in 1:t) { + # stochastic survival values + VU.s.alpha <- estBetaParams(VU.Sx, VU.s.sd.vec^2)$alpha + VU.s.beta <- estBetaParams(VU.Sx, VU.s.sd.vec^2)$beta + VU.s.stoch <- rbeta(length(VU.s.alpha), VU.s.alpha, VU.s.beta) + + # stochastic fertilty sampler (gaussian) + VU.fert.stch <- rnorm(length(VU.popmat[,1]), VU.pred.p.mm, VU.m.sd.vec) + VU.m.arr[i,,e] <- ifelse(VU.fert.stch < 0, 0, VU.fert.stch) + + VU.totN.i <- sum(VU.n.mat[,i], na.rm=T) + VU.pred.red <- VU.a.lp/(1+(VU.totN.i/VU.b.lp)^VU.c.lp) + + diag(VU.popmat[2:(VU.age.max+1),]) <- (VU.s.stoch[-(VU.age.max+1)])*VU.pred.red + VU.popmat[VU.age.max+1,VU.age.max+1] <- 0 + VU.popmat[1,] <- VU.m.arr[i,,e] + VU.n.mat[,i+1] <- VU.popmat %*% VU.n.mat[,i] + + VU.s.arr[i,,e] <- VU.s.stoch * VU.pred.red + + } # end i loop + + VU.n.sums.mat[e,] <- ((as.vector(colSums(VU.n.mat))/VU.pop.found)) + + if (e %% itdiv==0) print(e) + +} # end e loop + +VU.n.md <- apply(VU.n.sums.mat, MARGIN=2, median, na.rm=T) # mean over all iterations +VU.n.up <- apply(VU.n.sums.mat, MARGIN=2, quantile, probs=0.975, na.rm=T) # upper over all iterations +VU.n.lo <- apply(VU.n.sums.mat, MARGIN=2, quantile, probs=0.025, na.rm=T) # lower over all iterations + +par(mfrow=c(1,3)) +plot(yrs,VU.n.md,type="l", main = "", xlab="year", ylab="pN1", lwd=2, ylim=c(0.95*min(VU.n.lo),1.05*max(VU.n.up))) +lines(yrs,VU.n.lo,lty=2,col="red",lwd=1.5) +lines(yrs,VU.n.up,lty=2,col="red",lwd=1.5) + +VU.s.add <- VU.m.add <- rep(0, VU.age.max+1) +for (m in 1:iter) { + VU.s.add <- rbind(VU.s.add, VU.s.arr[ceiling(VU.gen.l):(t+1),,m]) + VU.m.add <- rbind(VU.m.add, VU.m.arr[ceiling(VU.gen.l):(t+1),,m]) +} +VU.s.add <- VU.s.add[-1,] +VU.m.add <- VU.m.add[-1,] + +VU.s.md <- apply(VU.s.add, MARGIN=2, median, na.rm=T) # mean s over all iterations +VU.s.up <- apply(VU.s.add, MARGIN=2, quantile, probs=0.975, na.rm=T) # upper over all iterations +VU.s.lo <- apply(VU.s.add, MARGIN=2, quantile, probs=0.025, na.rm=T) # lower over all iterations + +plot(VU.age.vec,VU.s.md,type="l", main = "", xlab="age", ylab="s", lwd=2, ylim=c(0.95*min(VU.s.lo),1.05*max(VU.s.up))) +lines(VU.age.vec,VU.s.lo,lty=2,col="red",lwd=1.5) +lines(VU.age.vec,VU.s.up,lty=2,col="red",lwd=1.5) + +VU.m.md <- apply(VU.m.add, MARGIN=2, median, na.rm=T) # mean s over all iterations +VU.m.up <- apply(VU.m.add, MARGIN=2, quantile, probs=0.975, na.rm=T) # upper over all iterations +VU.m.lo <- apply(VU.m.add, MARGIN=2, quantile, probs=0.025, na.rm=T) # lower over all iterations + +plot(VU.age.vec,VU.m.md,type="l", main = "", xlab="age", ylab="m", lwd=2, ylim=c(0.95*min(VU.m.lo),1.05*max(VU.m.up))) +lines(VU.age.vec,VU.m.lo,lty=2,col="red",lwd=1.5) +lines(VU.age.vec,VU.m.up,lty=2,col="red",lwd=1.5) +par(mfrow=c(1,1)) +