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NICK CASH
Department of Biological Sciences
Murray State University
Mentor: Terry
L. Derting
Title of Research: Land Between The Lakes as a Potential Reintroduction Site for Nicrophorus americanus (Coleoptera: Silphidae; American burying beetle): Occurrence of mammalian prey and scavenging competitors
Presented at: Kentucky Academy of Sciences
ABSTRACT
The American burying beetle (Nicrophorus americanus, ABB) is an endangered carrion beetle important in recycling nutrients back into ecosystems. Land Between the Lakes National Recreation Area (LBL) lies central to the ABB’s historic range and is currently under consideration for ABB re-introduction. A critical component of ABB ecology is the availability of rodent-host carcasses (70-120g) for reproduction and rearing young. Carcass availability is a function of rodent and competing scavenger populations. We assessed LBL as a potential re-introduction site for ABB by conducting a two-part study. First, we examined the current small mammal population within four habitat types (grassland, two stages of fire-managed woodland, and unmanaged forest) using live trap grids. Density and species of competing scavengers at a given site were assessed using camera traps. Four grids of each habitat type were surveyed for a total of 2352 trap nights. Our results indicated significantly more small mammals >70g in grassland sites and significantly more small mammals <70g in recent burn sites, compared with old burn and unmanaged forest sites. There was no significant difference in competitor abundance among the habitats. We also investigated direct competition between Nicrophorus beetles and vertebrate scavengers by monitoring rat carcasses for 72 hours. Significant differences in competitive pressure occurred among the habitat types, with highest competition in recent burn sites and lowest competition in forest sites. Despite our low capture rates of small mammals, large numbers of Nicrophorus spp. found during beetle surveys indicated that critical carrion resources were sufficiently available to support at least some carrion beetle species. Also, Nicrophorus beetles were able to compete successfully with vertebrate scavengers in obtaining carcasses. We propose that grassland sites within LBL will provide the most suitable habitat for ABB in terms of small mammal availability and lower competitive pressure. |
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