Habitat, Distribution and Genetics of the New England Cottontail

The Conservation Genetics Laboratory at the University of Rhode Island (URI) is currently studying habitat, distribution and genetics of the New England cottontail (Sylvilagus transitionalis). This is an ongoing project that began in the fall of 2010.

Why are we interested in the New England Cottontail?

Populations of the New England cottontail (NEC), Rhode Island’s only native cottontail, have been in decline for many years.  Historically, NEC were most abundant as farms in New England were abandoned and began reverting to early successional habitats.  As the forests in the area have matured, the population of NEC has decreased throughout its range and is now a candidate for listing as an endangered species by the U.S. Fish and Wildlife Service.  The other species of cottontail that is more common in the area is the Eastern cottontail (Sylvilagus floridanus), an introduced species that is almost identical to the New England cottontail.  Because they are so similar in appearance, the most reliable way to distinguish between the two species is to perform DNA analysis.

To better understand the distribution, genetics and habitat requirements of NEC, over 85 volunteers worked to survey about 90 locations throughout the state during the winter of 2011 (Figure 1).  Volunteers searched their areas for rabbit pellets, tracks and any other signs of rabbit activity. The survey locations were chosen using the early successional habitat model developed by Bill Buffum of URI, a habitat suitability index model for NEC developed by Steve Fuller of the Wildlife Management Institute, and historical known locations of NEC.

Why are we collecting fecal samples?

Volunteers have collected over 700 fecal samples from the 90 locations throughout Rhode Island in the winter of 2011.  In addition to allowing us to identify the species of cottontail in each location in an easy and non-invasive manner, we can learn a lot about a population from their DNA:

  • Microsatellites, also known as “DNA fingerprinting,” is a tool that is widely used to distinguish individual humans and is just as useful to distinguish individual rabbits.
  • With microsatellite markers we can study the genetic variation of New England cottontail populations.  Low genetic variation is often caused by habitat fragmentation/low connectivity between populations, reducing the gene pool.
  • Populations with low genetic variation can be distinguished and targeted for supplemental release of captive breed rabbits.

URI is also working with the Roger Williams Park zoo to initiate a captive breeding program.   The zoo is currently housing several New England cottontails that were captured in Connecticut, and several areas in RI and throughout New England are being considered as release sites for the offspring of these animals.  The health and genetics of all animals in the captive breeding program are being closely monitored to ensure that the newly released animals will be a successful addition to the population.

Habitat Surveys

To better understand the habitat requirements of NEC, and help to refine the predictive habitat suitability model, intensive vegetation surveys will be conducted throughout the summer.  Areas that are known to have NEC will be revisited along with areas that do not have any rabbits.  The vegetation structure as well as the predominant species in these areas will be measured and quantified.  These vegetation surveys will help to identify the “ideal NEC habitat” and also give us clues as to why NEC is not always found in the same areas as eastern cottontails.

How can you help?

Next year we will be continuing/expanding our surveys for NEC.  If interested, you can volunteer to survey your private land, nearby public lands, or pre-designated survey locations.   Training on survey protocols and all sampling materials will be provided.

For more information on this project, or for information on volunteer next winter email amy.gottfried@gmail or call the URI Conservation Genetics Laboratory at (401) 874-5812.