Assessment of fall season habitat and coverboard use by snakes in a restored tallgrass prairie community

From Firenze University Press Journal: Acta Herpetologica

University of Florence
5 min readFeb 9, 2024

Carter Dollen, Glacier Creek Preserve, University of Nebraska Omaha

Tracy J. Coleman, Glacier Creek Preserve, University of Nebraska Omaha

Travis R. Robbins, Glacier Creek Preserve, University of Nebraska Omaha

Prairie restoration is a common management strategy to increase the biodiversity of an ecosystem, restore native populations and communities, and store large amounts of available carbon (Jordon et al., 1988; Samson and Knopf, 1994; Anderson, 2009; Guiden et al., 2021). Restora-tions typically include the removal of agriculture plots, replanting native plant species, and relying on the “Field of Dreams” paradigm that if you build it species native to the area will come (Guiden et al., 2021). As such, this paradigm involves building a suitable habitat for organ-isms in hopes they will find and stay in the restored area. Research shows prairie restorations can increase the abun-dance of animals, including herpetofauna such as snakes (King and Vanek, 2020). Although not readily observed because of their elusive nature, snakes can reach high abundance and greatly influence natural communities by influencing abundance and behavior of other species (Hisaw and Gloyd, 1926; Kotler et al., 1993; Sperry et al., 2008; Willson and Winne, 2018; King and Vanek, 2020). Accurately monitoring success of restoration efforts is difficult, however, because each restoration effort is unique, including the sampling techniques utilized. Sampling herpetofauna in tallgrass environments can be difficult due to the cryptic nature of reptiles and amphibians (Fitch, 1987; Szaro et al., 1988). Visual sam-pling is a common method for sampling snake species (Foster, 2012), however, small, cryptic, or camouflaged species are often difficult to detect in areas of thick veg-etation due to their slender bodies (Turner, 1977; Ward et al., 2017). One efficient form of sampling includes the use of coverboards constructed out of sheets of various heat conducting materials, such as metal, wood, rubber, or asphalt roofing (Fitch, 1987; Engelstoft and Ovaska, 2000). Coverboards can significantly increase detection of snakes compared to simple visual surveys (Halliday and Blouin-Demers, 2015). These covers provide attractive areas for snakes and other herpetofauna to seek refuge and an efficient way for scientists to observe, count, or capture snakes (Halliday and Blouin-Demers, 2015). Coverboards of different types provide microhabitats of varying temperatures and humidities allowing individ-uals a choice regarding suitable areas for cover (Engelst-oft and Ovaska, 2000). These microhabitats are impacted by the habitats in which they are placed and seasonality due to falling or rising temperatures. During the cooler months, for instance, snakes may utilize substrates or objects that absorb or retain heat to maintain their opti-mal body temperature more efficiently (Engelstoft and Ovaska, 2000). Individual preferences for specific micro-habitats can arise through various needs associated with age, sex, shedding, food ingestion, circadian rhythms, and reproductive condition (Lilywhite, 1987). Sampling effi-ciency associated with coverboard type can therefore vary based on target species, habitat type, season, and interac-tions among these factors. These relationships mean that the coverboard types used can impact species-specific encounter rates during surveys and biodiversity assess-ments and can influence the herpetofaunal community composition detected (Grant et al., 1992; Engelstoft and Ovaska, 2000; Hampton, 2007).Identifying habitat and microhabitat use of snake species in the tallgrass prairies of the Great Plains of North America has received relatively little attention, despite prairies being the largest vegetative community in North America (Samson and Knopf, 1994) and the Great Plains constituting one-third of the United States (Deitz, 2022). Understanding these preferences can be beneficial to conservation efforts and lead to more accurate and efficient sampling for specific species and communities. In this study, we used metal and plywood coverboards to assess snake habitat and coverboard preference in a restored tallgrass prairie system that includes a habitat gradient from prairie floodplain to upland prairie. We specifically compared the preferences of the snakes for metal or wooden coverboards in association with habitat type, humidity, and ambient temperatures.We sampled snakes within the Allwine Tract of Gla-cier Creek Preserve (41.19759N, -96.29893W), a 212 ha (525 acres) preserve that encompasses an entire sub watershed in eastern Nebraska, United States. The Allwine Tract (65 ha; 160 acres) was donated to the University of Nebraska at Omaha in 1959. In 1970, 57 ha (140 acres) of agricultural land within the Allwine Tract were seeded with five native prairie grass species and then over-seeded with a diverse mix of local native forbs in the following years. Between 2009 and 2019 an additional 147 ha (365 acres) were purchased and added to the preserve, includ-ing a mix of agriculture, wetlands, and woodlands. The reconstructed prairie is managed with a 3-year prescribed fire return interval that occurs in mid-spring, where no more than 2 of the 5 units are burned in one year. Addi-tional details about the site can be found in Bragg et al. (2016), Dere et al. (2019), and Manning et al. (2022).Data was collected during a 3-week period from Sep-tember 17 to October 4, 2021, during three time blocks of 7:00–9:00, 14:00–16:00, and 18:00–20:00 CT (morning, afternoon, and dusk, respectively). Four data collection events occurred during each of the time blocks. We sam-pled 10 stations that were established in spring of 2018, reflecting 41 months since establishment. Sampling effi-ciency of artificial retreats can increase with time since establishment; however, studies have found that efficien-cies reach asymptotic maximums within 12 months, well within our time frame (Grant et al., 1992; Croak et al, 2010). The stations ran along a north-south transect (800 m) that crossed Glacier Creek with 5 stations on the south slope and 5 stations on the north slope (104 m average distance between stations; min = 27 m, max = 145 m). Each station consisted of two artificial coverboards: a uni-formly sized metal (corrugated, galvanized sheet metal) and plywood (12.2 mm or 1/2 inch thickness) coverboard each measuring approximately 122 x 122 cm (L x W) and placed approximately 1.5 m from each other. Therefore, there were 20 artificial retreats evenly divided between the two types of material. A Kestrel 5000 environmental meter (Nielsen-Kellerman Company) was used to collect relative humidity and temperature data.During each sampling event each board was lifted, and the area underneath scanned to count number of individuals and identify snake species and life stage as either juvenile or adult. The Kestrel was then placed under the board to acclimate for 90 seconds. We record-ed the relative humidity and temperature from the Kes-trel and repeated this process for each of the stations along the transect, whether or not snakes were present.


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