Effects of forest removal on amphibian migrations: implications for habitat and landscape connectivity

Abstract

Summary 1.Habitat loss is a leading cause of global amphibian declines. Forest removal is a particularly significant threat because an estimated 82% of amphibians rely on forests for part of their lives. 2. Biphasic amphibians rely on suitable terrestrial habitat to support their post-metamorphic growth and survival and also to maintain appropriate habitat and landscape connectivity. 3. We created 4 replicate, 16-ha experimental arrays in the southeastern USA to examine the effects of forest removal on migratory movements of adult biphasic amphibians. Each array contained four forest-harvesting treatments that included an unharvested control, a partially harvested stand, a clearcut with coarse woody debris retained, and a clearcut with coarse woody debris removed. 4. Some amphibian species emigrated from wetlands in significantly greater numbers through forest controls compared with harvested treatments. Also, salamanders were generally more sensitive to forest removal than were frogs, with a significantly greater proportion of salamanders migrating through forested habitat compared to frogs. 5. For several species, individuals were significantly more likely to avoid clearcuts when emigrating compared to immigrating. Individuals that emigrated into clearcut treatments were more likely to reverse direction and return to wetlands in some species. 6. Synthesis and applications . Our study identifies one mechanism by which forest removal shapes the abundance and distribution of amphibians in terrestrial habitat. To promote the persistence of amphibian populations, conservation efforts should focus on preserving forest habitat adjacent to reproduction sites. Such measures are especially important where forest habitat connects local populations or where it links reproduction sites to other habitat features necessary for amphibian growth, survival, or overwintering.

Terrestrial distribution of pond‐breeding salamanders around an isolated wetland

“…Individuals that stay in low quality habitat, such as clear-cuts, incur reduced growth and survival (Rothermel and Semlitsch 2006). However, if individuals choose to retreat to more suitable forest habitat (Todd et al 2009), the higher resulting densities may produce similar negative effects on vital rates, including fecundity. A relatively modest reduction in juvenile/adult annual survivorship (e.g., from 70% to ,60%) may be sufficient to induce local extinction in the absence of increased immigration rates or other compensatory effects (Taylor and Scott 1997).…”

The cause of global amphibian declines: a developmental endocrinologist's perspective

“…Habitat fragmentation, logging, drainage of wetlands and filling of wetlands that historically served as breeding habitat for amphibian populations are all examples of habitat loss that negatively impact recruitment by reducing available habitats for breeding or limiting the ability of adults to reach suitable breeding habitats (Adams, 1999;Davidson et al, 2002;Davidson et al, 2001;Delis et al, 1996;Harper et al, 2008;Semlitsch et al, 2008;Todd et al, 2009). As discussed earlier, habitat loss is the most important cause of local declines and there is a vast amount of literature addressing this issue, so we will not cover it extensively here.…”

Climate and land-use changes effects on the distribution of a regional endemism: Melanophryniscus sanmartini (Amphibia, Bufonidae)

“…Melanophryniscus sanmartini could take an advantage of this opportunity to expand depending on habitat availability in future landscapes as mediated by land use change. LULCC is primarily responsible for the global amphibian decline (Todd et al, 2009). Forestry expansion has been identified as the main risk factor for M. sanmartini (Lavilla & Langone, 2004).…”