TWEL Kevin Swanson Thesis

Movements, survival, and habitat relationships of snowshoe hares following release in northeast Ohio
 
Kevin A. Swanson, MS
Advisor: Robert Gates
 
 
The geographic distribution of snowshoe hares (Lepus americanus) is primarily associated with northern boreal forests in North America. Snowshoe hares were once indigenous to the snow-belt region of northeastern Ohio, but were extirpated by the early 1900s. Attempts were made to reintroduce snowshoe hares in northeastern Ohio during the 1950s. However, these releases failed to establish a viable population. Causes of failure are unknown because the releases were poorly documented and monitored. Factors limiting snowshoe hare populations at the southern periphery of their geographic range are poorly understood. Therefore, I monitored an experimental release of 232 snowshoe hares in northeastern Geauga and southwestern Ashtabula Counties, Ohio during winters 2000-2001. My goals were to: (1) determine the feasibility of establishing a breeding population by releasing hares during winter and, (2) identify the most suitable habitats for snowshoe hares in northeast Ohio. I monitored movements, survival, and habitat use by 160 radio-marked hares during January-June, 2000 and 2001. Hares were released on 8 forest sites that differed in age of dominant trees and wetland coverage. Hares released during 2000 lost more weight before release (P<0.001) and had lower condition (P=0.054) than in 2001. Hares dispersed farther (P<0.001) from release sites in 2001 (937 ± 52 m) than in 2000 (562 ± 41 m). January-June survival was higher (P=0.002) in 2001 (43%) compared to 2000 (21%). Improved pre-release condition and more prolonged snow cover were associated with increased movement and survival in 2001. Predation by coyotes (Canis latrans) and red foxes (Vulpes vulpes) was the major source of mortality (53-63% of deaths) each year. Mean 95% kernel home ranges were large (55-67 ha) and did not differ between years. Hares used shrub-dominated wetlands, wetland forests (10-20 years old), and early successional forests (<10 years old) in proportions greater than their availability across the study area. Hares used forests >20 years old and non-forested habitats less than their availability in the study area. Dispersal from release sites was lowest in mixed wetland/upland and early regenerating forests during 2000 and 2001. Based on apparent survival during January-March (37-62%), approximately 51 hares survived until the start of the breeding season in 2000, and 58 survived in 2001. Survival was highest among hares released in wetland (37-44%) and regenerating forest stands (22-47%) both years. Reproductive success is the most critical factor that will determine the long-term viability of snowshoe hares after reintroduction into northeast Ohio. Two pregnant females, 8 reproductively active males, and 1 juvenile male were captured during live-trapping in 2000 and 2001. Long-term success of the reintroduction effort will require supplemental releases until a network of local populations is established. Forested landscapes containing ≥11% shrub-scrub wetlands and ≥5% early successional forests are essential to support breeding populations and should be the focus of future releases. Populations should be established in contiguous wetland/forest tracts with connectivity between habitat patches to facilitate inter-population dispersal. Efforts to restore snowshoe hares in northeast Ohio raises awareness of the need to protect native landscapes from development and conserve early successional and forested wetland habitats.