Uncovering Urban Reptile and Amphibian Diversity

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by Christine Healy, Wildlife Biologist

Coverboards are typically placed along ecotones, where species diversity is expected to be greatest. The corrugated tin board, pictured above, was positioned along a forest edge where larger deciduous trees meet a more open, sandy landscape.

How do you survey for animals that spend most of their time hidden under leaf litter or wedged between fallen tree limbs and rocks?

In the case of reptiles and amphibians, the answer is to use coverboards!

Coverboards are materials that are intentionally placed within a potential habitat, often along ecotones (where different habitat types- e.g., wetland and forest, field and forest, etc. come together) that trap moisture and retain heat, creating favorable conditions for our “cold-blooded” (ectothermic) friends. Researchers often arrange coverboards in long transects or arrays and collect data on the diversity of the community underneath the boards as compared to the surrounding environment. This technique was used by NJDEP Division of Fish and Wildlife to survey for herptiles in 17 wildlife management areas in the early 2000s (Golden, 2004). A total of 30 species were recorded during the first year of the study, including long-tailed salamanders, pine barrens tree frogs, and northern pine snakes, all of which are listed as threatened in New Jersey.   

This wooden board provides potential cover for snakes and turtles that sun themselves on the nearby railroad tracks.

I asked my dad, Jim if he would donate some of his Fourth of July (and subsequently Labor Day) weekend to help me prepare coverboards for an urban wildlife project in Union County (and later Bordentown). With a very enthusiastic YES! we were off to the hardware store. I learned that his enthusiasm was a product of grand plans to emblazon CWF’s logo onto each board, rather than his intention of making me a spectacle in the Lowes parking lot (people will openly stare if you cut metal on a makeshift sawhorse composed of shopping carts using a battery-powered jigsaw, FYI), though I’m sure that only added to his glee. The resulting formaldehyde-free plywood and corrugated tin boards are undeniably the most beautiful coverboards I’ve ever seen. My team and I arranged them into linear and circular transects at our field sites late in the summer to help us get to know some of the more elusive residents.

In order to foster appropriate microhabitat, coverboards need time to weather and become one with the environment. After a patient 2.5 month wait, we returned to our field sites in early October to determine if anything was calling our boards home.

So far, we’ve found garter snakes and redback salamanders (along with a diversity of slugs, white-footed mice, and a handful of eastern moles). We’ll check on the boards a few more times before winter sets in, then start up again following the spring thaw. Just like whisky and fine cheddar, coverboards only improve with age, so we hope to discover additional species before the conclusion of the study.

Continued Reading:

https://www.nj.gov/dep/fgw/ensp/pdf/literature/cover-board_surveys_herps_2003.pdf
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