Profiting from prior information in Bayesian analyses of ecological data

Abstract

1.Most ecological studies include prior information only implicitly, usually in their design or the discussion of results. In this study, two examples demonstrate that using Bayesian statistics to incorporate basic ecological principles and prior data can be very cost-effective for increasing confidence in ecological research. 2. The first example is based on examining the effects of an experimental manipulation of the habitat of mulgara Dasycercus cristicauda , a marsupial of inland Australia. The second example is based on observational mark-recapture data to estimate the annual survival of the European dipper Cinclus cinclus , a passerine in France. 3. In the mulgara example, the prior information obtained from an observational study increased confidence that there was an adverse effect of experimental habitat manipulation on the species. The results suggested that the capture rate of mulgara was reduced to approximately one-quarter by reduction of vegetation cover. 4. In the European dipper example, prior information based on the body mass of the species and estimates of annual survival of other European passerines was shown to be worth between 1 and 5 years of mark-recapture field data. 5. Synthesis and application s. Body mass can be used to predict annual survival of European passerines and other animals. Results of observational studies can provide prior information in experimental studies of impacts of habitat change. By using Bayesian methods, such prior information, if represented in a coherent and logical way, can be cost-effective for adding certainty to ecological studies.

Strict coupling between the development ofPlanktothrix rubescensand microcystin content in two nearby lakes south of the Alps (lakes Garda and Ledro)

“…The Bayesian approach allows obtaining a posterior distribution of the parameters (e.g., regression slopes) given the data and existing knowledge (priors) for these parameters (McCarthy and Masters, 2005;McCarthy, 2007). With a Bayesian approach, every parameter has an entire distribution (posterior) which can be represented as a graph (e.g., using histograms, like in Figs.…”

Evidence that a Highway Reduces Apparent Survival Rates of Squirrel Gliders

“…A number of ecological studies have improved the precision of model estimates by including Bayesian informative priors (e.g., Martin et al 2005, McCarthy and Masters 2005, McCarthy et al 2008). In our study, there was a small but noticeable improvement in precision for estimates of apparent annual survival rates when some prior information was included compared with using vague priors, but there was little or no improvement in the precision of the relative apparent survival rate when informative priors were used.…”

Big Decisions and Sparse Data: Adapting Scientific Publishing to the Needs of Practical Conservation

“…As a result, population viability models are not routinely used for Avian Conservation and Ecology -Écologie et conservation des oiseaux 2(2): 14 http://www.ace-eco.org/vol2/iss2/art14/ management decisions that cannot wait for extended periods of data collection. However, McCarthy and Masters (2005) showed that a prior estimate of survival derived from an allometric relationship could potentially be used to improve precision if few data were available for the species of concern. When measured in terms of precision, prior information derived from allometry was initially worth approximately 5 yr of mark-recapture data in the case study chosen (McCarthy and Masters 2005).…”

“…However, McCarthy and Masters (2005) showed that a prior estimate of survival derived from an allometric relationship could potentially be used to improve precision if few data were available for the species of concern. When measured in terms of precision, prior information derived from allometry was initially worth approximately 5 yr of mark-recapture data in the case study chosen (McCarthy and Masters 2005). Bayesian methods can also combine expert opinion with data (Martin et al 2005), then expert opinion can be evaluated (McCarthy and Masters 2005) and differences of opinion compared (Crome et al 1996).…”

“…When measured in terms of precision, prior information derived from allometry was initially worth approximately 5 yr of mark-recapture data in the case study chosen (McCarthy and Masters 2005). Bayesian methods can also combine expert opinion with data (Martin et al 2005), then expert opinion can be evaluated (McCarthy and Masters 2005) and differences of opinion compared (Crome et al 1996).…”