Landscape Complementation and Metapopulation Effects on Leopard Frog Populations

Abstract

For many species, not all required resources are contained in breeding habitat. Such species depend on landscape complementation, i.e., linking together different landscape elements through movement, to complete their life cycles. We suggest that the dichotomous habitat classification of many metapopulation analyses (habitat vs. nonhabitat) masks our ability to detect metapopulation effects for such species. We tested this using a species for which landscape complementation is obligate and metapopulation structure is likely: Rana pipiens, the northern leopard frog. We used breeding chorus survey data to index relative abundance of leopard frogs in 34 ''core'' ponds and conducted Poisson regression analysis to determine the effects on frog density of local pond habitat, availability of summer habitat (landscape complementation), and number of occupied ponds in the surrounding landscapes (metapopulation structure). All of these factors had statistically significant effects on frog density. However, when summer habitat was not included in the statistical model, the metapopulation structure was no longer significant; i.e., its effect was masked. Our results suggest that one must be cautious in applying the results of metapopulation analyses to species for which the habitat vs. nonhabitat categorization of the landscape is not appropriate. The potential for rescue and recolonization to maintain a regional population must be assessed within the constraints of the entire landscape.

Influence of habitat parameters on common skipper frog (Euphlyctis cyanophlyctis) in Chittagong

“…Understanding habitat requirements and habitat use of amphibians are major challenges in their conservation (Marsh et al 1999, Harlet et al 2006. Habitat selection of anurans is known to be influenced by environmental factors, like the abiotic temperature and pH (Banks and Beebee, *Corresponding author: wahed.chowdhury@cu.ac.bd 1987, Pope et al 2000), and the biotic like the competitors, predators, and the degree to which resources are distributed spatially (Crump 1991, Daniels 1992, Nie et al 1999, Lin et al 2008, Indermur et al 2009). Very recently, Akram et al (2015) worked on the influence of some abiotic and biotic factors on the habitat selection of some anurans in Pakistan and Lemckert (2006) worked on the correlation between frogs and pond attributes in Australia.…”

Terrestrial habitat requirements of nesting freshwater turtles

“…Organisms with biphasic natural histories complicate protected area development because they require both aquatic and terrestrial habitats. Specifically, core habitats of semi-aquatic species, including many amphibians (Semlitsch 1998;Pope et al, 2000;Porej et al, 2004), snakes (Roe et al, 2003), turtles (Burke and Gibbons, 1995), mammals (Kruchek, 2004), birds (Naugle et al, 1999), and insects (Bried and Ervin, 2006), encompass terrestrial uplands that are critical for conservation measures aimed at maintaining biodiversity (Semlitsch and Jensen, 2001). …”

A Bayesian method for assessing multi-scale species-habitat relationships

“…Unfortunately, information regarding the ecological processes shaping the distribution or abundance of a species is often lacking, let alone the spatial scale at which these processes may act. To overcome such limitations of knowledge researchers can collect data on habitat conditions at multiple spatial scales and perform model selection to choose a single 'characteristic' scale of their species' response (e.g., Būhning-Gaese and Katrin 1997; Pope et al 2000;van Langevelde 2000;Steffan-Dewenter et al 2002;Holland et al 2004;Gray et al 2010; Thornton and Fletcher 2014). While potentially informative, the notion of a single 'characteristic' scale to which a species may associate fails to consider that, in general, the processes that define a species' niche often interact, with the possibility of multiple explanatory variables acting at different spatial scales (e.g., Cushman and McGarigal 2002).…”