| dc.description.abstract | The longleaf pine (Pinus palustris) ecosystem is an ecologically significant region of North America, yet its geographic extent has been greatly reduced by several factors including anthropogenic fire suppression. There is, however, increasing interest in restoring longleaf pine forests, and this necessarily entails the use of prescribed fire. Longleaf pine forests naturally burned as a result of lightning-ignited fires in late spring and early summer (referred to as growing season burns), yet land managers in the Southeast have historically used prescribed fire in late winter (referred to as dormant season fire) to avoid detrimental effects of growing season fire on wildlife, especially nesting game birds like northern bobwhite (Colinus virginianus). While research is indicating season of burn can have substantial effects on the plant community of longleaf pine forests, less is known about the influence of season of burn on the life history of native and endemic vertebrates in the longleaf pine ecosystem. Because federal and state agencies are charged with management of public lands, which may entail management for the native ecosystem and game species, it is important to establish the influence of season of burn on animal species. Thus, we undertook a study at Conecuh National Forest (CNF), Alabama to evaluate productivity, survival, and population dynamics of northern bobwhites in longleaf pine forests burned during the growing and dormant seasons.
Aspects of Northern Bobwhite productivity at CNF were similar and dissimilar to other studies conducted elsewhere in their geographic range. Nest success at CNF did not vary appreciably with time since most recent prescribed fire or season of last prescribed fire, but nests in areas that had burned, regardless of season of burn, were 1.8 times more likely to survive a day-length interval as were nests in unburned longleaf pine forests. Estimated nest success was 47.0% over a 23-day incubation period, one of the highest estimates in the published literature. Of Northern Bobwhites that survived through the nesting season (1 September), 17.9% of males and 27.3% of females had hatched = 1 nest. Published estimates of reproductive success for males are similar to those documented at CNF, yet most other published estimates for females are ˜ 75%. Future work should investigate causes for low female reproductive success.
Daily survival rate of Northern Bobwhites was explained by several factors: daily mobility, season of burn, and timber type. Extent of daily mobility had the greatest influence on survival of Northern Bobwhites at CNF, and daily survival decreased as daily mobility increased. Northern Bobwhites in growing season burned longleaf pine forests were 1.5 times more likely to survive each day than individuals in dormant season burned longleaf pine forests. Of several timber types (pine, pine-hardwood, upland hardwood, bottomland hardwood, and miscellaneous areas [food plots, etc.]), Northern Bobwhite daily survival was highest in pine stands. Daily movement rate varied by season of year and whether an individual was associated with an area of unburned habitat. Daily mobility of Northern Bobwhites varied intra-annually, and was greatest in late spring prior to the breeding season. Northern Bobwhites associated with food plots were less mobile than those not associated with food plots.
Based on a literature review and demographic analyses described above, we constructed several matrix population models for Northern Bobwhites. Population models based on a literature search indicated that observed variation in productivity can have the greatest observed impact on population growth rate, yet changes to survival rates in the non-breeding season has the greatest potential impact on population growth rate. Population models based on demographic rates estimated for the CNF Northern Bobwhite population sugges | en_US |
