Quality habitat loss has reduced the hare's presence on its historic range
HARRISBURG, Pa., June 14, 2012 /PRNewswire-USNewswire/ -- The following release was written by Joe Kosack, Wildlife Conservation Education Specialist, Pennsylvania Game Commission:
At the direction of its Board of Game Commissioners, the Pennsylvania Game Commission will take a closer look at what's limiting the state's indigenous snowshoe hare population. Insufficient quality habitat has been the primary suspect for some time. The Board also took action recently to reduce significantly the snowshoe hare season for the upcoming license year.
Historically, the Game Commission's approach to managing snowshoes focused largely on augmenting the state's population with repeated stockings – to the tune of more than 33,000 hares –from 1918 to 1981. It also has whittled what was once a month or longer hunting season to less than a week. But the agency's management emphasis to sustain substantial white-tailed deer numbers during the twentieth century fostered forest conditions – particularly in the hare's primary range in the northern tier's mountainous and swampy areas – that inadequately supported snowshoes in many places. Deer, which have similar dietary needs as hares, had snowshoes at a disadvantage, given the whitetail's numbers, mobility, reach and consumption capacity. But with increased management emphasis in recent years to balance deer populations with habitat in many Wildlife Management Units (WMUs) across the northern tier, maybe the playing field has been leveled some.
"It's been said we really don't know what's happening to the species, that we haven't performed enough research on hares," Game Commissioner Jay Delaney said. "Maybe it's time we find out, especially with forest habitat rebounding in many areas of the snowshoe's primary range. Hares are important to hunters. They're a maintenance species in our Wildlife Action Plan. So it makes sense to try and do something more for hares, if we can."
In an effort hoped to bolster hare numbers where they've sagged or disappeared, and to increase their potential as a game species, the Board closed the snowshoe hare hunting, except for WMUs 2F, 2G and 3A, at its April quarterly meeting. The Board is keenly interested in why hares are doing well in some areas, and not others.
"Many factors influence the snowshoe hare in Pennsylvania," said Calvin W. DuBrock, Game Commission Bureau of Wildlife Management director. "Two of the most prevalent are that our state is near the southern limit of the hare's range in North America, and snowshoes have a fairly restricted range within our borders.
"Our Game-Take Surveys indicate hares still maintain a presence – in some cases, significant populations – in many of those counties where they have been found historically. But the loss of acceptable habitat, from development and forest maturation and fragmentation has been plaguing hares for decades. Where good habitat can be found in their range, you'll find hares."
Working in concert with the U.S. Geological Survey's Pennsylvania Cooperative Fish and Wildlife Research Unit at Penn State, the Game Commission plans to develop a revised management approach for snowshoe hares. It'll start by conducting fieldwork to assess the densities and range of the state's hare population and to identify areas of suitable and potential hare habitat. That data then will be correlated to measure the relationship between hares and habitat.
"This fieldwork will help us confirm the habitat needs of hares and will hopefully shed light on their ability to disperse to improved habitat and from deteriorating habitat within their current range in Pennsylvania," DuBrock said. "It will help us solidify our management approach for hares and improve snowshoe populations."
The Board's action to close the hare season in all but three WMUs statewide marks the third time in the agency's 117-year history snowshoe hare season has been closed. The other times were statewide season closures in 1936, and from 1939 through 1942, when hares were hunted mostly in November. Since 1954, the hare season has been one week or less.
However, hunting is not believed to have an adverse effect on hare populations, according DuBrock.
"Habitat quality and availability are clearly the most important factors affecting population distribution and status at this time," DuBrock said. "The hare harvest in Pennsylvania has declined slowly over the past 20 years, and so has hunter participation, which can be influenced by many factors ranging from weather to hunter access."
Hunters have helped the Game Commission keep tabs on the state's snowshoe population by reporting their harvests – and in later years, effort – in the annual Game-Take Survey and other hunter surveys since 1930. But hare hunters over the past 20 years have been a small group – they currently represent less than one percent of the state's hunting population – and their hunting for some time has been limited to a few days between Christmas and New Year's Day, which can be influenced greatly by weather.
"Extrapolating reliable hare harvest and hunter data is difficult, and the product serves more as a guide in trends than a weighted measurement," DuBrock said.
With that in mind, from 2006 to 2010, the Game-Take Survey shows the state's hunters have reported an average annual harvest of about 1,100 hares. Annual hare hunter numbers over the five-year period averaged about 3,700. Hare harvests have been recorded by the agency since 1930, when about 20,000 were estimated taken by hunters in a 25-day season. In 1980, 15,200 were estimated taken by hunters in a six-day season. In 1990, Game-Take estimated a harvest of 3,600 hares in a six-day season.
The Game Commission's hare harvest over time reflects a diminishing harvest. The only way that decline could have been confirmed was through continuous monitoring, which didn't happen. Consequently, biologists must deduce population trends from harvest data. The harvest drop over time also has been influenced by declining hare hunter numbers, loss of quality habitat and harvest reporting modifications to improve accuracy in data collection over time. But eight decades of harvest data do show consistent hare hunter success in Pennsylvania.
What's interesting about the snowshoe's range in Pennsylvania is that it still roughly parallels the range hares held at the start of the 20th Century. In 1903, Samuel N. Rhoads' status assessment of hares in The Mammals of Pennsylvania and New Jersey indicates their primary range was in the state's northern tier, with pockets in Alleghenies. In 2010, the most recent snowshoe hare range map in Terrestrial Vertebrates of Pennsylvania: A Complete Guide to Species of Conservation Concern shows the hare's primary range still is generally in the Poconos and Allegheny National Forest, with secondary range from the state's northcentral counties south through the Laurel Highlands. Terrestrial Vertebrates of Pennsylvania was developed as an appendix of Pennsylvania's Wildlife Action Plan.
The Board's action in April limits hare hunting to three WMUs in northcentral Pennsylvania. Hare hunting will be closed in the state's remaining 19 WMUs, including those that contain all of the Poconos Mountains.
Further north, snowshoe hares are doing fine in New York, although loss of quality habitat also is starting to pinch the population some there. The state's hare season varies, depending upon the wildlife management unit hunted, and season length ranges from roughly one to five months; more than a dozen wildlife management units also are closed annually to hare hunting. The state's five-year annual average for hare harvest from the 2006-07 license-year to 2010-11 was 28,902, according to the New York State Small Game Hunter Survey. The five-year annual average for hunters was 18,434.
Snowshoes are an endangered species in Maryland, and have been presumed extirpated there for years. In West Virginia, snowshoes are hunted from early November through February, but the state does not keep harvest data currently.
"Our snowshoe hunters enjoyed a long season and were successful, but that is more due to access then a growing population," said Ken Krantz, a West Virginia Division of Natural Resources biologist. "I believe clear-cutting on the Monongahela National Forest has helped the state's hare population."
Hares are listed as endangered in Virginia and found in only one county, according to the Virginia Department of Game and Inland Fisheries' website. The southern range of hares once extended through the Appalachian Mountains south into North Carolina and Kentucky.
Keeping snowshoes in Pennsylvania's secondary hare range through the Allegheny Mountains of Somerset and Cambria counties and the High Plateaus of northcentral Pennsylvania is an important management consideration, according to Dr. Duane Diefenbach, unit leader at the U.S. Geological Survey's Pennsylvania Cooperative Fish and Wildlife Research Unit at Penn State University.
"The snowshoe hare's continued presence on this secondary range helps to preserve an important pathway for north/south gene flow within its southern range," said Dr. Diefenbach, who wrote the snowshoe hare account for the Terrestrial Vertebrates of Pennsylvania. "That's important to Pennsylvania and West Virginia, the snowshoe's last strongholds in their southern Appalachian range. If we can ensure there's an adequate amount of suitable habitat that has sufficient connectivity between established hare population centers, there's a chance."
Pennsylvania's Wildlife Action Plan noted several habitat issues that likely have limited the snowshoe hare's ability to augment its population or expand its limited range in Pennsylvania. Habitat deficiencies included loss of early successional forests (five to 15 years old); loss of lower elevation mixed forests dominated by sugar maple, beech, birch and conifers; and loss of conifer plantations, hemlock stands and high-quality, high elevation shrub-scrub swamps. Other habitat factors include loss of preferred plants to deer overbrowsing and hemlocks to wooly adelgid infestation, habitat fragmentation (especially in the Poconos), poor forest regeneration from acid deposition, and poor forest management on private lands.
"Predation is probably the greatest mortality factor hares face," Dr. Diefenbach wrote in his Terrestrial Vertebrates of Pennsylvania snowshoe hare account. "It involves most mammalian and avian predators that occur in the state. The large number of potential predators may explain why hare populations exhibit little evidence of population cycling in Pennsylvania."
Still, habitat shortcomings and deficiencies are the primary factors influencing hare abundance in Pennsylvania. Not predators. Not lack of camouflaging snowfall. Not overharvest by hunters. A more aggressive habitat management program designed to maintain early-successional forestland and a similar outreach program on private lands would like help snowshoes. But it comes with no guarantee.
Trying to jumpstart the existing Pennsylvania snowshoe population with stocked hares also could be a risky step, because it presents the potential to compromise healthy hare populations with some disease, disorder or virus the imported hares may harbor. Research – in Pennsylvania and elsewhere – has shown that the risks often far outweigh the benefits when relocating wild animals in some instances.
"The future of snowshoe hares in Pennsylvania is tied directly to habitat," DuBrock said. "They likely have the capability to increase their numbers in Pennsylvania, but only if there are more brushy thickets, primarily high-quality early successional forestlands, and mixed-hardwood and boreal swamps. But this sort of optimal habitat has been shrinking – not increasing – in the Commonwealth. That's bad for snowshoes, as well as other species of conservation concern, such as the golden-winged warbler, Appalachian cottontail and the American woodcock.
"Changing this trend through habitat management would help species of conservation concern, game animals and a plethora of other less-burdened species and truly represent conservation progress in its broadest application. It's a step in the right direction to help our snowshoe hare population and provide collateral benefits for a whole host of wildlife along the way."
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NOTE: Photographs to accompany this news release are available from the Game Commission's website (www.pgc.state.pa.us) by clicking on "News Releases" and then selecting "Release #065-12."
SOURCE Pennsylvania Game Commission