Table 1.

Three nested generalized linear models of species density with all samples combined. The first model (‘climate’) includes the climatic parameters. ‘+ canopy/litter’ adds the classification variable (whether the samples are from the canopy or litter). ‘+abundance’ adds abundance (N) as a measure of sampling effort. All climatic variables have been converted to z-scores. The two more complex models are significant given AIC minimization. Note that the effect of canopy/litter is significant, unless the number of individuals is included. Parameter estimates and AIC values do not include non-significant terms.

climatecanopy/litterabundance
estimates84% CIestimates84% CIestimates84% CI
intercept3.075**3.0503.1003.056**3.0293.0823.063**3.0393.088
mean annual temperature0.514**0.4680.5610.513**0.4660.5560.565**0.5350.595
annual precipitation0.208**0.1820.2340.217**0.1920.2430.246**0.2240.268
temperature range−0.130**−0.181−0.079−0.105**−0.157−0.054n.s.n.s.n.s.
precipitation seasonality−0.115**−0.141−0.089−0.096**−0.123−0.070−0.095**−0.120−0.070
canopy/litter (canopy)0.169*0.1150.222n.s.n.s.n.s.
number of individuals0.135**0.1250.144
AIC− 28 259− 28 278− 28 528
r2 observed ∼ predicted0.4520.4650.522
  • *p < 0.01.

  • **p < 0.0001.

  • n.s., not significant at p = 0.05.