Herpetofauna distribution across habitat gradients

In the Upper Midwest, There is limited quantitative information as to how the herpetofauna community (i.e., reptiles and amphibians, hereafter herp community) varies along the grassland – savanna- forest gradient. This lack of baseline data makes it difficult to determine the impacts of management activities, including prescribed fire.

The authors of this study surveyed the herp community along a prairie to forest gradient. Sites were established in northwest Indiana in 1999. Drift fence arrays with funnel traps were set up at 25 sites. To determine how the herp community responded to fire and changes in vegetation structures site variables were measured at each array. Site variables included environmental variables (e.g., % cover bare ground, stem density, canopy cover) and fire history (e.g., time since last fire).

There were opposing effects of fire on the herp community, with some species having strongly positive responses and other species strongly negative. The authors suggest that this pattern is the result of frequent fire having a generally positive effect on herps by maintaining habitat being coupled with short term negative impacts of prescribed fire (e.g. decreased cover). Additionally, diversity in the habitat requirements of species, for example some reptiles seek out open areas while others avoid them, can lead to opposing trends in the data.

The complexities of these patterns demonstrate the value in assessing the herp community as a whole and over time. If research or monitoring efforts are focused on a single species or habitat type, the results may not represent the broader herp community or predict the response in neighboring habitat types.

Management Implications

• The habitat needs of reptiles and amphibians differ, leading to differences in the herp community across a grassland to forest habitat gradient
• Maintaining diverse habitats, with a range of fire histories, can support a wider range of habitat needs
• Herpetofauna communities are most diverse in savanna habitats

For further summary of  the study's results and implications for management, view or download a PDF version of the research brief: "Herpetofauna distribution across habitat gradients." 

The original paper is:

Grundel, Ralph, David A Beamer, Gary A. Glowacki, Krystalnn J. Frohnapple, Noel B. Pavlovic. 2015. Opposing responses to ecological gradients structure amphibian and reptile communities across a temperate grassland-savanna-forest landscape. Biodiversity Conservation 24:1089-1108.