PARENT SESSION
Oral Session 2: Avian Ecology I: Habitat and Disturbance.
Presiding: D Miles and C Lepczyk
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room A 106.
The effects of landscape characteristics on ruffed grouse movements.
Yoder, James*,1, Marschall, Elizabeth1, Swanson, David 2, 1 The Ohio State University, Columbus, OH2 Ohio Department of Natural Resources, Columbus, OH
ABSTRACT- It is well established that ruffed grouse prefer heterogeneous habitat consisting of forest stands of varying age classes and density. Little is known, however, on how grouse populations respond to fragmentation of a landscape through the loss of forested habitat to agricultural and residential development. To address specifically how dispersal decisions and movements may be affected by large-scale landscape characteristics we used radio-telemetry data collected from 225 Ruffed Grouse during 1996-99 in southeastern Ohio. Approximately 75% of juveniles undergo fall natal dispersal and 40% of adults undergo a fall seasonal dispersal. Using individual locations buffered at multiple spatial scales to define landscapes extents, we compared metrics quantifying habitat composition, degree of fragmentation, and amount of core and edge habitat between dispersing and non-dispersing birds. We also examined how landscape characteristics affected juvenile and adult dispersal distances, rates of movement, and home range sizes. We found juveniles undergoing fall natal dispersal came from areas significantly less fragmented and composed of a higher proportion of forested habitat than non-dispersers. Of those juveniles that dispersed, dispersal distance was negatively related to percent forest cover. Adults who underwent seasonal dispersal were more likely to come from fragmented areas with a low proportion of forest habitat than those that did not disperse, but dispersal distances were positively related to percent forest cover and negatively related to edge density. Thus, our data suggest that adult and juvenile ruffed grouse movements are significantly affected by changes in landscape composition and structure but in profoundly different ways.
Key words: forest fragmentation, Bonasa umbellus, dispersal, Ruffed Grouse