First we are going to set up initial values.
The PEcAn.priors::fit.dist
helps to choose the best fit parameter distribution given some sample
datasets.
glopnet.grass <- glopnet.data[which(glopnet.data$GF == 'G'), ] # GF = growth form; G=grass
## turnover time (tt)
glopnet.grass$tt <- 12/10^(glopnet.grass$log.LL)
ttdata <- data.frame(tt = glopnet.grass$tt[!is.na(glopnet.grass$tt)])
## specific leaf area
##glopnet.grass$sla <- 1000/ (0.48 * 10^glopnet.grass$log.LMA)
glopnet.grass$sla <- 1000/ (10^glopnet.grass$log.LMA)
sladata <- data.frame(sla = glopnet.grass$sla[!is.na(glopnet.grass$sla)])
The fit.dist
function takes a vector of point estimates
(in this case 125 observations of Specific Leaf Area from GLOPNET
database are stored in sladata
.
First, it prints out the fits of a subset of distributions (the ‘f’ distribution could not be fit). Second, it prints the
## a b AIC
## weibull 2.06 19.000 888.759
## lognormal 2.65 0.677 923.220
## gamma 2.95 0.175 899.403
## distribution a b n
## 1 weibull 2.06 19 125
prior.dists <- rbind('SLA' = fit.dist(sladata, dists ),
'leaf_turnover_rate' = fit.dist(ttdata, dists))
## a b AIC
## weibull 2.06 19.000 888.759
## lognormal 2.65 0.677 923.220
## gamma 2.95 0.175 899.403
## a b AIC
## weibull 1.83 5.180 187.125
## lognormal 1.35 0.687 195.072
## gamma 2.90 0.630 187.098
slaprior <- with(prior.dists['SLA',], pr.dens(distribution, a, b))
ttprior <- with(prior.dists['leaf_turnover_rate',], pr.dens(distribution, a, b))
The priorfig
function visualizes the chosen prior
(line), with its mean and 95%CI (dots) as well as the data used to
generate the figure.
prior.figures <- list()
prior.figures[['SLA']] <- priorfig(
priordata = sladata,
priordensity = slaprior,
trait = data.frame(id = "SLA", figid = "SLA", units="1"))
prior.figures[['leaf_turnover_rate']] <- priorfig(
priordata = ttdata,
priordensity = ttprior,
trait = data.frame(id = "leaf_turnover_rate", figid = "left_turnover_rate", units="yr-1"))
prior.figures
## $SLA
##
## $leaf_turnover_rate
This code is not run here - data are provided in .csv file below. This code requires connection to the BETYdb MySQL server.
wullschleger.species <- vecpaste(unique(wullschleger.data$AcceptedSymbol))
## load functional type data from BETY
con <- function() {query.bety.con(username = "bety", password = "bety",
host = "localhost", dbname = "bety")}
functional.data <- query.bety(paste("select distinct AcceptedSymbol, scientificname, GrowthHabit, Category from species where AcceptedSymbol in (", wullschleger.species, ") and GrowthHabit is not NULL and Category is not NULL;"), con())
write.csv(functional.data, 'inst/extdata/wullschleger_join_usdaplants.csv')
Picking up with the Wullschleger dataset joined to USDA Plants functional type classifications …
wullschleger.data <- read.csv(system.file('extdata/wullschleger1993updated.csv', package = 'PEcAn.priors'))
functional.data <- read.csv(system.file('extdata/wullschleger_join_usdaplants.csv', package = 'PEcAn.priors'))
subshrubs <- rownames(wullschleger.data) %in% c(grep('Shrub',wullschleger.data$GrowthHabit), grep('Subshrub', wullschleger.data$GrowthHabit))
########## 2. Merge functional type information into Wullschleger data
wullschleger.data <- merge(wullschleger.data, functional.data, by = 'AcceptedSymbol')
########## 3. Classify by functional type
## grass: any Graminoid Monocot
grass <- with(wullschleger.data, GrowthHabit == 'Graminoid' & Category == 'Monocot')
## forbs/herbs = forb
forb <- with(wullschleger.data, GrowthHabit == 'Forb/herb' | GrowthHabit == 'Vine, Forb/herb')
## woody = Shrubs, Subshrubs or Trees, add category to a few with missing information,
woody <- with(wullschleger.data, scientificname %in% c('Acacia ligulata', 'Acacia mangium', 'Arbutus unedo', 'Eucalyptus pauciflora', 'Malus', 'Salix') | rownames(wullschleger.data) %in% c(grep('Shrub', GrowthHabit), grep('Subshrub', GrowthHabit), grep('Tree', GrowthHabit)))
## gymnosperms
gymnosperm <- wullschleger.data$Category == 'Gymnosperm'
## ambiguous is both woody and herbaceous, will drop
ambiguous <- wullschleger.data$GrowthHabit %in% c("Subshrub, Shrub, Forb/herb, Tree", "Tree, Subshrub, Shrub", "Tree, Shrub, Subshrub, Forb/herb", "Subshrub, Forb/herb")
wullschleger.data$functional.type[grass] <- 1
wullschleger.data$functional.type[forb] <- 3
wullschleger.data$functional.type[woody & !gymnosperm] <- 4
wullschleger.data$functional.type[woody & gymnosperm] <- 5
wullschleger.data <- subset(wullschleger.data, !ambiguous)
############# Estimating SE and n ##################################
##verr, jerr: the "asymptotic" errors for Vcmax, Jmax using SAS nlim
##vucl,vlcl,jlcl,jucl: are upper and lower confidence limits of 95%CI
##Calculate SD as (1/2 the 95%CI)/1.96
wullschleger.data$vsd <- (wullschleger.data$vucl-wullschleger.data$vlcl)/(2*1.96)
##Calculate effective N as (SE/SD)^2 + 1
wullschleger.data$neff <- (wullschleger.data$vse/wullschleger.data$vsd)^2 + 1
wullschleger.data$se <- sqrt(wullschleger.data$vsd*sqrt(wullschleger.data$neff))
## recode species to numeric
species <- unique(wullschleger.data$scientificname)
sp <- rep(NA, nrow(wullschleger.data))
for(i in seq(species)){
sp[wullschleger.data$scientificname == species[i]] <- i
}
############# Scale values to 25C ##################################
wullschleger.data$corrected.vcmax <- PEcAn.utils::arrhenius.scaling(
wullschleger.data$vcmax,
old.temp = wullschleger.data$temp,
new.temp = 25)
############# Create data.frame for JAGS model ##################################
wullschleger.data <- data.frame(Y = wullschleger.data$corrected.vcmax,
obs.prec = 1 / (sqrt(wullschleger.data$neff) * wullschleger.data$se),
sp = sp,
ft = wullschleger.data$functional.type,
n = wullschleger.data$neff)
## Summarize data by species
wullschleger.vcmax <- wullschleger.data %>%
group_by(sp) %>%
summarise(Y = mean(Y),
obs.prec = 1/sqrt(sum((1/obs.prec)^2)),
ft = mean(ft), # identity
n = sum(n)) %>%
dplyr::select(-sp)
Few measurements of Vcmax for C4 species were available. ###### Miscanthus: Wang D, Maughan MW, Sun J, Feng X, Miguez FE, Lee DK, Dietze MC, 2011. Impact of canopy nitrogen allocation on growth and photosynthesis of miscanthus (Miscanthus x giganteus). Oecologia, in press
dwang.vcmax <- c(19.73, 40.35, 33.02, 21.28, 31.45, 27.83, 9.69, 15.99, 18.88, 11.45, 15.81, 27.61, 13, 21.25, 22.01, 10.37, 12.37, 22.8, 12.24, 15.85, 21.93, 23.48, 31.51, 23.16, 18.55, 17.06, 20.27, 30.41)
dwang.vcmax <- data.frame(Y = mean(dwang.vcmax),
obs.prec = 1/sd(dwang.vcmax),
ft = 2, #C4 Grass
n = length(dwang.vcmax))
Kubien and Sage 2004. Low-temperature photosynthetic performance of a C4 grass and a co-occurring C3 grass native to high latitudes. Plant, Cell & Environment DOI: 10.1111/j.1365-3040.2004.01196.x
Data from figure 5 in Kubien and Sage (2004), average across plants grown at 14/10 degrees and 26/22 degrees
Massad, Tuzet, Bethenod 2007. The effect of temperature on C4-type leaf photosynthesis parameters. Plant, Cell & Environment 30(9) 1191-1204. DOI: 10.1111/j.1365-3040.2007.01691.x
data from fig 6a
massad.vcmax.data <- data.frame(vcmax = c(17.1, 17.2, 17.6, 18, 18.3, 18.5, 20.4, 22.9, 22.9, 21.9, 21.8, 22.7, 22.3, 25.3, 24.4, 25.5, 25.5, 24.9, 31.2, 30.8, 31.6, 31.7, 32.5, 34.1, 34.2, 33.9, 35.4, 36, 36, 37.5, 38.2, 38.1, 37.4, 37.7, 25.2, 25.5),
temp = c(20.5, 24.6, 21, 19, 21.9, 15, 19.6, 14.3, 20.8, 23.4, 24.8, 25.9, 24.1, 22.8, 27.9, 31.7, 35.5, 39.3, 37.9, 42.4, 41.5, 48.7, 33.3, 33.3, 31.5, 39.1, 38.8, 43.3, 50, 38.4, 35.7, 34.4, 31.9, 33.9, 32.1, 33.7))
massad.vcmax <- with(
massad.vcmax.data,
PEcAn.utils::arrhenius.scaling(
old.temp = temp,
new.temp = 25,
observed.value = vcmax)
)
massad.vcmax <- data.frame(Y = mean(massad.vcmax),
obs.prec = 1/(sd(massad.vcmax)),
n = length(massad.vcmax),
ft = 2)
##### Combine all data sets
all.vcmax.data <- rbind(wullschleger.vcmax,
dwang.vcmax,
## xfeng.vcmax,
kubien.vcmax,
massad.vcmax)
writeLines(con = "vcmax.prior.bug",
text = "model{
for (k in 1:length(Y)){
Y[k] ~ dnorm(beta.ft[ft[k]], tau.y[k])T(0,)
tau.y[k] <- prec.y*n[k]
u1[k] <- n[k]/2
u2[k] <- n[k]/(2*prec.y)
obs.prec[k] ~ dgamma(u1[k], u2[k])
}
for (f in 1:5){
beta.ft[f] ~ dnorm(0, tau.ft)
}
tau.ft ~ dgamma(0.1, 0.1)
prec.y ~ dgamma(0.1, 0.1)
sd.y <- 1 / sqrt(prec.y)
## estimating posterior predictive for new C4 species
pi.pavi <- Y[length(Y)]
diff <- beta.ft[1] - beta.ft[2]
}")
library(rjags)
## Loading required package: coda
## Linked to JAGS 4.3.2
## Loaded modules: basemod,bugs
j.model <- jags.model(file = "vcmax.prior.bug",
data = vcmax.data,
n.adapt = 500,
n.chains = 4,
inits = inits)
## Compiling model graph
## Resolving undeclared variables
## Allocating nodes
## Graph information:
## Observed stochastic nodes: 194
## Unobserved stochastic nodes: 9
## Total graph size: 614
##
## Initializing model
mcmc.object <- coda.samples(model = j.model, variable.names = c('pi.pavi', 'beta.ft', 'diff'),
n.iter = iter)
mcmc.o <- window(mcmc.object, start = iter/2, thin = 10)
pi.pavi <- data.frame(vcmax = unlist(mcmc.o[,'pi.pavi']))
vcmax.dist <- fit.dist(pi.pavi, n = sum(!is.na(vcmax.data$Y)))
## a b AIC
## weibull 3.54 24.300 14780.8
## lognormal 3.02 0.394 15482.8
## gamma 8.06 0.367 15082.4
prior.dists <- rbind(prior.dists, 'Vcmax' = vcmax.dist)
vcmax.density <- with(vcmax.dist, pr.dens(distribution, a, b), xlim = c(0,50))
######### Vcmax Prior Plot
vcmax.c4 <- all.vcmax.data$ft == 2
vcmax.data <- all.vcmax.data[,c('ft', 'Y')]
vcmax.data$mean <- vcmax.data$Y
vcmax.data$se <- 1/(sqrt(all.vcmax.data$n) * all.vcmax.data$obs.prec)
vcmax.data <- vcmax.data[,c('ft', 'mean', 'se')]
#vcmax.mean <- all.vcmax.data$Y[!c4,]
#vcmax.se <- with(all.vcmax.data[!c4,], 1/(sqrt(n) * obs.prec))#[reorder]
#c4.mean <- all.vcmax.data$Y)[c4]
#c4.se <- with(all.vcmax.data, 1 / (sqrt(n) * obs.prec) )[c4]
prior.figures[['Vcmax']] <- priorfig(priordensity = vcmax.density,
trait = data.frame(id = 'Vcmax', figid = 'Vcmax', units = 'umol CO2 m-2 s-1'),
xlim = range(c(0, max(vcmax.data$mean)))) +
geom_point(data = subset(vcmax.data, ft != 2),
aes(x=mean, y = (sum(vcmax.c4) + 1:sum(!vcmax.c4))/3000), color = 'grey60') +
geom_segment(data = subset(vcmax.data, ft != 2),
aes(x = mean - se, xend = mean + se,
y = (sum(vcmax.c4) + 1:sum(!vcmax.c4))/3000,
yend = (sum(vcmax.c4) + 1:sum(!vcmax.c4))/3000),
color = 'grey60') +
## darker color for C4 grasses
geom_point(data = subset(vcmax.data, ft == 2),
aes(x=mean, y = 1:sum(vcmax.c4)/2000), size = 3) +
geom_segment(data = subset(vcmax.data, ft == 2),
aes(x = mean - se, xend = mean + se,
y = 1:sum(vcmax.c4)/2000, yend = 1:sum(vcmax.c4)/2000))
print(prior.figures[['Vcmax']])
## Warning: Removed 1 row containing missing values or values outside the scale range
## (`geom_segment()`).
Fitting priors to expert constraint.
rriskDistributions
The rriskDistributions useful for estimating priors …
as well as individual functions for each distribution such as
get.<somedist>.par
that provide nice diagnostic plots
(e.g. compare chosen points to cdf) for example, to compute the
parameters of a Gamma distribution that fits a median of 2.5 and has a
95%CI of [1, 10]:
The function fit.pecr
provides a GUI to explore the fits
of a range of distributions, e.g.:
produces this: