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 influence of human-dominated landscapes on breeding birds in the Midwest United States.
Lepczyk, Christopher*,1, Radeloff, Volker1, Flather, Curtis2, Pidgeon, Anna1, Hammer, Roger1, Liu, Jianguo3, 1 University of Wisconsin-Madison, Madison, WI2 USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO3 Michigan State University, East Lansing, MI
ABSTRACT- Bird population levels can vary greatly across both the extent of their range and among years. Although numerous mechanisms have been put forth to explain this variation, human effects may be particularly important. To assess the role of human influence on bird populations, we investigated both anthropogenic land cover and housing density, in relation to total, native, and exotic species diversity and trends of 137 species across 408 replicate landscapes in the Midwest U.S. We hypothesized that (1) total and native species diversity would be maximum at intermediate levels of human influence, whereas exotic diversity would continue to increase; and, (2) the amount of human influence affects the abundance of species occurring in each landscape. A negative quadratic relationship existed between total and native avian diversity and both measures of human influence. We found that anthropogenic land cover had a stronger influence than housing density and that exotic species diversity increased with both measures of human influence. A total of 75 (55%) species displayed significant relationships with either one or both measures of human influence, with 35 related to anthropogenic land cover, 5 related to housing density, and 35 related to both measures. Overall, 33 species had negative relationships with human influence, 14 had positive relationships, and 28 displayed a combination of positive and negative relationships. Our findings indicate that humans are having a detectable and broad scale influence on birds in the Midwest.
Key words: Urbanization, Human Influence, BBS