How trees affect amphibians

Posted on July 20, 2015

Temporary (seasonal) ponds are the main type of habitat for many aquatic species. Because of the ecological links between freshwater and terrestrial environments, disturbances in the vicinity of temporary ponds can threaten aquatic species. For example, dispersing amphibians may find it difficult to cross open habitats created by the removal of trees. At the same time however, there’s evidence that ponds that are heavily shaded by trees tend to support fewer amphibian species. So how might forest canopy cover be best managed to support pond biodiversity? In an experiment conducted in the Yale Myers Forest in Connecticut, U.S.A., trees were removed within a 90o arc radiating 25 m from the southern shoreline of six shaded ponds. Another eight similar ponds were left unaffected as controls. The study ponds averaged 1300 m2 in area and 89 cm in maximum depth. Data collected over a five-year monitoring period showed that water temperatures and the numbers of amphibian species were significantly higher in the shade-reduced ponds than the controls. At the treatment sites, the number of shade-intolerant amphibians rose while the number of shade-tolerant forms stayed the same. Therefore it seems that a modest environmental manipulation – one that’s large enough to affect aquatic conditions but too small to have a major landscape impact – can have a beneficial effect on amphibian biodiversity.

Reference: Skelly, D.K. et al. 2014. Experimental canopy removal enhances diversity of vernal pond amphibians. Ecological Applications 24(2), 340–345