A Range-Wide Survey to Determine the Current Distribution of New England Cottontails

Abstract

The abundance and distribution of New England cottontails (NEC; Sylvilagus transitionalis) have been declining for several decades. Remnant populations in some regions are known to be vulnerable to extirpation but little is known about the status of populations in most areas. We conducted a survey of the historic range (ca. 1960) of NEC to determine the current distribution and relative status of extant populations. Because NEC were sympatric with eastern cottontails (S. floridanus) and snowshoe hares (Lepus americanus) in much of their historic range, identity of resident lagomorphs was based on DNA extracted either from tissue of captured cottontails or from fecal pellets of free‐ranging lagomorphs. We searched 2,301 patches of suitable habitat and detected NEC in 162. We identified 5 disjunct populations in approximately 14% of the historic range. Forest maturation and fragmentation are the most plausible explanations for the widespread decline of NEC. Contraction of the historic distribution was toward eastern and southern edges where a variety of anthropogenic disturbances (e.g., brushy edges of highways and railroad corridors and idle portions of agricultural fields) provided habitat. Land‐ownership patterns (dominated by small acreages) and land‐use activities (expanding development and limited forest management) within the currently occupied range of NEC suggest a continued decline of suitable habitats. As a result, we recommend efforts to enhance remaining populations of NEC that include responses at 2 spatial scales. At the population or landscape scale, current land uses should guide habitat manipulations that expand existing populations. At the regional scale, we recommend consideration should be given to increasing dispersal among remnant populations, possibly by generating “stepping stones” of suitable habitat. In addition to improving long‐term viability of NEC, other species of conservation concern that are dependent on early successional habitats will benefit from these efforts.

Population genetic structure and history of fragmented remnant populations of the New England cottontail (Sylvilagus transitionalis)

“…Cottontail abundance within these areas is unknown, with the exception of a rough estimate of approximately 300 rabbits in Maine (the majority of the area occupied by the MENH population; Litvaitis and Jakubas 2004); recent evidence shows this population has declined further since that estimate (Fenderson and Kovach, unpublished data). Rangewide, Litvaitis et al (2006) only detected New England cottontails in 7% of the 2,301 patches of suitable habitat searched. Further, many of these patches were small (\3 ha) and likely only supported 3-4 rabbits within a highly fragmented landscape.…”

“…Increased development in New England in the last 50 years has resulted in further fragmentation of the remaining suitable habitat. Consequently, New England cottontails have not simply returned to presettlement population levels, but instead are suffering continuous population decline (Litvaitis 2003;Litvaitis et al 2006;Tash and Litvaitis 2007).…”

“…1960;Fig. 1;Litvaitis et al 2006). A recent range-wide inventory found that the species currently exists in five geographically disjunct locations (hereafter referred to as geographic populations): southern Maine and southeastern New Hampshire (MENH); the Merrimack Valley in central New Hampshire (NH-MV); Cape Cod, Massachusetts (CC); parts of eastern Connecticut and Rhode Island (CTRI); and western Connecticut, southeastern New York and southwestern Massachusetts (CTNY).…”

“…A recent range-wide inventory found that the species currently exists in five geographically disjunct locations (hereafter referred to as geographic populations): southern Maine and southeastern New Hampshire (MENH); the Merrimack Valley in central New Hampshire (NH-MV); Cape Cod, Massachusetts (CC); parts of eastern Connecticut and Rhode Island (CTRI); and western Connecticut, southeastern New York and southwestern Massachusetts (CTNY). The approximate area occupied by these populations ranges from 1,260 km 2 for NH-MV to 4,760 km 2 for CTNY (Litvaitis et al 2006). Cottontail abundance within these areas is unknown, with the exception of a rough estimate of approximately 300 rabbits in Maine (the majority of the area occupied by the MENH population; Litvaitis and Jakubas 2004); recent evidence shows this population has declined further since that estimate (Fenderson and Kovach, unpublished data).…”

Obtaining high-quality DNA from elusive small mammals using low-tech hair snares

“…Second, NGS enables biologists to study populations of elusive and rare species, a task that can prove difficult with more traditional live trapping approaches (Piggott and Taylor 2003 and references therein). And third, NGS can potentially increase sample sizes by reducing disturbance to animals, sampling efforts and costs, thus helping to minimise biases in estimates of population parameters (Banks et al 2003;Litvaitis et al 2006). This latter point may prove crucial when dealing with threatened species since biased estimates of population parameters may result in inappropriate management.…”