Informing management with monitoring data: the value of Bayesian forecasting

Planning and decision-making can be improved by access to reliable forecasts of ecosystem state, ecosystem services, and natural capital. Availability of new data sets, together with progress in computation and statistics, will increase our ability to forecast ecosystem change. An agenda that would lead toward a capacity to produce, evaluate, and communicate forecasts of critical ecosystem services requires a process that engages scientists and decision-makers. Interdisciplinary linkages are necessary because of the climate and societal controls on ecosystems, the feedbacks involving social change, and the decision-making relevance of forecasts.

Recently, the results from several long-term individual-based population studies of ungulates have been published. One major conclusion is that the population dynamics of ungulates in predator-free environments is strongly influenced by a combination of stochastic variation in the environment, and population density. Both density dependence and environmental stochasticity operate through changes in life history traits, correlated with variation in body weight. This generates delays in the response of the population to changes in environment. In the absence of predation, a stable equilibrium is therefore unlikely to exist between an ungulate population and its food resources. This thorough understanding of the mechanisms generating population fluctuations suggests that studies of ungulates will provide an important source for examining effects of long-term changes in the environment, for instance, resulting from a climatic change.