Date of Award

8-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Forestry and Environmental Conservation

Committee Member

Dr. David S. Jachowski, Committee Chair

Committee Member

Dr. Robert F. Baldwin

Committee Member

Dr. Patrick Hiesl

Committee Member

Dr. Catherine M. Bodinof Jachowski

Abstract

The eastern spotted skunk (Spilogale putorius) is a species of conservation concern in many portions of its range and has experienced a decline since the early to mid-1990s. However, little is known about the subspecies that inhabits peninsular Florida, the Florida spotted skunk (S. p. ambarvalis), which may still be abundant. To gather more information on this diminutive carnivore's ecology and to clarify its role as a predator of the endangered Florida grasshopper sparrow (Ammodramus savannarum floridanus), we conducted studies in 2016 and 2017 on the den site selection and diet of Florida spotted skunks in a dry prairie ecosystem in central Florida, where these 2 species co-occur. For the den site selection study, we tracked 36 individual skunks to 757 den sites and measured the habitat and den characteristics of these sites. Den sites were most often located in mammal burrows (61.6 %), followed by above-ground sites (35.5%), gopher tortoise (Gopherus polyphemus) burrows (1.5%), depressions (1.2%), and hollow logs ( < 0.3%). Each of these used sites was compared to a paired, random available den site using discrete choice analysis. We found that male and female nonbreeding skunks at our study site were 5 times more likely to select a mammal burrow over a tortoise burrow and that the relative probability of selection of a den site increased by 45% for each 1-burrow increase in the number of nearby burrows. Similarly, breeding female skunks selected mammal burrows and shallow depressions over gopher tortoise burrows by 16- and 13-fold, respectively, and relative probability of selection of a den site increased by 75% for every 1-burrow increase in the number of nearby burrows. Our findings suggest that den characteristics may be more important than habitat characteristics to Florida spotted skunk den site selection in dry prairie and that skunks in this ecosystem may be habitat generalists. For our diet study on this subspecies, we collected hair samples from skunks and tissue samples from potential food items across our study site. We subsequently conducted a stable isotope analysis to determine which food items comprised the Florida spotted skunk diet at our site. Our results suggested that skunks in the dry prairie have an omnivorous and generalist diet, as no food item groups composed a majority of their diet. The most prevalent food items in our study were millipedes (~27%) and insectivorous amphibians and reptiles (~25%). Insectivorous birds, like the grasshopper sparrow, comprised no more than approximately 15% of the skunk diet at our site. Overall, these studies contribute to the knowledge of Florida spotted skunk ecology and help elucidate the skunk’s role as a predator of grassland birds in dry prairie ecosystems, while also providing some recommendations for land managers to consider for reducing predation pressure on grasshopper sparrows by these skunks. However, this research should be expanded upon to better discern Florida spotted skunk diet composition and selection, and to determine if the patterns observed in our studies on diet and denning ecology hold in other portions of this subspecies’ range.

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