Ruffed Grouse Population Ecology in the Appalachian Region PDF Download

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Category : Grouse
Languages : en
Pages : 40

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Book Description
S2The Appalachian Cooperative Grouse Research Project (ACGRP) was a Multistate cooperative effort initiated in 1996 to investigate the apparent decline of ruffed grouse (Bonus umbellus) and improve management throughout the central and southern Appalachian region (i.e., parts of Ohio, Pennsylvania, Rhode Island, Kentucky, West Virginia, Virginia, and North Carolina, USA). Researchers have offered several hypotheses to explain the low abundance of ruffed grouse in the region, including low availability of early-successional forests due to changes in land use, additive harvest mortality, low productivity and recruitment, and nutritional stress. As part of the ACGRP, we investigated ruffed grouse population ecology. Our objectives were to estimate reproductive rates, estimate survival and cause-specific mortality rates, examine if ruffed grouse harvest in the Appalachian region is compensatory, and estimate ruffed grouse finite population growth. We trapped >3,000 ruffed grouse in autumn (Sep-Nov) and spring (Feb-Mar) from 1996 to September 2002 on 12 study areas. We determined the age and gender of each bird and fitted them with necklace-style radiotransmitters and released them at the trap site. We tracked ruffed grouse >- 2 times per week using handheld radiotelemetry equipment and gathered data on reproduction, recruitment, survival, and mortality. Ruffed grouse population dynamics in the Appalachian region differed from the central portion of the species' range (i.e., northern United States and Canada). Ruffed grouse in the Appalachian region had lower productivity and recruitment, but higher survival than reported for populations in the Great Lakes region and southern Canada. Population dynamics differed between oak (Quercus spp.)-hickory (Carya spp.) and mixed-mesophytic forest associations within the southern and central Appalachian region. Productivity and recruitment were lower in oak-hickory forests, but adult survival was higher than in mixed-mesophytic forests. Furthermore, ruffed grouse productivity and recruitment were more strongly related to hard mast (i.e., acorn) production in oak-hickory forests than in mixed-mesophytic forests. The leading cause of ruffed grouse mortality was avian predation (44% of known mortalities). Harvest mortality accounted for 12% of all known mortalities and appeared to be compensatory. Population models indicated ruffed grouse populations in the Appalachian region are declining ([lambda] = 0.78-0.95), but differences in model estimates highlighted the need for improved understanding of annual productivity and recruitment. We posit ruffed grouse in the Appalachian region exhibit a clinal population structure characterized by changes in life-history strategies. Changes in life history strategies are in response to gradual changes in forest structure, quality of food resources, snowfall and accumulation patterns, and predator communities. Management efforts should focus on creating a mosaic of forest stand ages across the landscape to intersperse habitat resources including nesting and brood cover, adult escape cover, roosting sites, and, most importantly, food resources. Land managers can intersperse habitat resources through a combination of‍?c1earcutting, shelterwood harvest, group selection, and timber stand improvement including various thinnings and prescribed fire). Managers should maintain current ruffed grouse harvest rates while providing high quality hunting opportunities. We define high quality hunting as low hunting pressure, low vehicle traffic, and high flush rates. Managers can provide high quality hunting opportunities through use of road closures in conjunction with habitat management.S3.