Implications of climatic warming for conservation of native trees and shrubs in Florida

Ecological process models and empirical envelope models have been used to r elate climatic-change predictions to effects on plant species and vegetatio n. Climatic-envelope models arf, useful for simultaneous investigation of m any plant species whose range-limiting mechanisms are poorly known. They ar e most effectively applied in regions with strong temperature and moisture gradients and low relief. Their required databases are often relatively eas y to obtain. We provide an example involving the effect of six annual warmi ng scenarios, ranging from +1 degreesC to +2 degreesC and from +10% to -20% annual precipitation (some have greater warming in winter than in summer), on 117 native woody species in Florida (U.S.A.). Tree species at their sou thern range boundaries in several parts of Florida are likely to be negativ ely affected by as little as 1 degreesC warming if it is greater in winter than in summer or is accompanied by a 20% decrease in annual precipitation. Potential species responses to an identical type of 1 degreesC warming may be different for some conservation areas in the same region of Florida. Po tentially extensive disruption of some major woody ecosystems is predicted tinder certain types of 1 degreesC annual warming and under all types of 2 degreesC annual warming that were investigated. Additional consideration of nonclimatic factors suggests that many Potential effects on species and ec osystems are not underestimates of actual effects over a 100-year period of warming. Me recommend monitoring for decreased fertility and viability of ecologically important, temperate woody species near their southern range l imits in Florida. Early detection of such changes in fitness might then pro vide the for mitigations designed to alleviate more serious subsequent effe cts on biodiversity. Control of invasive, non-native plant species and prev ention of their additional introduction, human-assisted translocation of na tive subtropical plant species into previously temperate Parts of Florida, and restoration of more natural hydrological regimes are examples of potent ially useful mitigations if climatic warming continues.