Date of Award

Fall 1991

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Program/Concentration

Biology

Committee Director

Robert K. Rose

Committee Member

Gerald Levy

Committee Member

John Holsinger

Call Number for Print

Special Collections LD4331.B46 P33

Abstract

Southeastern shrews (Sorex longirostris) were trapped throughout southeastern Virginia and northeastern North Carolina to determine if any morphological characters could

be identified that would aid in the identification and distribution of the threatened subspecies Sorex l._ fisheri, endemic to the Great Dismal Swamp, the more upland nominate subspecies Sorex l. longirostris, and possible intergrades between the two subspecies. Animals were classified a priori into three groups, based on their location of capture. Animals collected from the Great Dismal Swamp National Wildlife Refuge (GDSNWR) and associated bottomland habitats were designated as "fisheri", animals collected farthest from the Swamp as "longirostris", and animals collected from areas located between these groups were designated as "unknown".

Cranial measurements taken from cleaned skulls revealed no skull character that could distinguish between the two subspecies. However, Principle Components Analysis (PCA) and Cluster Analysis determined that overall size of the skull was greatest from animals collected from within the Great Dismal Swamp, of intermediate value in animals collected in areas peripheral to the Swamp and smallest in animals collected farthest from the Great Dismal Swamp.

Using the three groups defined above, external measurements (body, tail and length of foot), were subjected to Discriminant Function Analysis (DFA) to classify and identify individual animals as to respective group. Generated probabilities for each respective animal by DFA was used to delineate the geographic distribution of the two subspecies as well as areas of intergradation.

Based on these analyses, Sorex l. fisheri populations were found to be genetically stable within the GDSNWR and its associated habitats, Sorex l. longirostris was found to occur in more upland habitats throughout the region, and intergrades were found in narrow zones of contact along the periphery of the GDSNWR and in areas where disturbance and draining of wetlands had occurred.

The current status of Sorex l. fisheri as a federally listed Threatened subspecies should be maintained due to the identification of intergrades and the threat of hybridization, as well as habitat alteration and disturbance in and near the GDSNWR.

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DOI

10.25777/j1q3-vh47

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