Wednesday, August 6, 2008: 8:40 AM
104 D, Midwest Airlines Center
Lisa A. McCauley, Northern Prairie Wildlife Research Center, South Dakota State University/ US Geological Survey, Jamestown, ND, David G. Jenkins, Biology, University of Central Florida, Orlando, FL and Pedro Quintana-Ascencio, Dept. of Biology, University of Central Florida, Orlando, FL
Background/Question/Methods Florida has undergone rapid urbanization, with nearly 1 million ha in Florida converted to urban use from 1985 to 2003. Within Florida, the Orlando metropolitan area has increased 83% since 1980 and is projected to increase 136%, to a population of 7.2 million by 2050. Forested wetland area declined 3% since 1980 and most (59%) of that loss was due to urbanization. Land cover analyses revealed that 135 forested wetlands (>3800 ha) were lost per year in Orange and Seminole Counties between 1990 and 2004, and that ½ of the lost wetlands were < 1 ha. Urbanization is an important landscape change for population and evolutionary biology: its effects are strong, essentially permanent, and exist in a gradient. Cypress (Taxodium distichum (L.) Rich.) is the dominant vegetation of forested wetlands in the Southeast and is sensitive to urbanization through loss of habitat, fire suppression, and alteration to hydrology. As part of a study on the effects of urbanization on cypress, we assessed spatial pattern and recruitment of cypress across an urbanization gradient. More than 2,300 cypress domes in Orange and Seminole Counties were digitized in GIS using aerial photography and land cover. An urbanization gradient was identified using surrounding land cover and domes were randomly sampled from each of five categories in the gradient (natural, agriculture, low urban, medium urban, high urban). Cypress recruitment and encroachment by other woody vegetation were evaluated at each dome. Results/Conclusions
Preliminary results indicate that spatial isolation of cypress domes significantly increases with greater urbanization and while the adult density remains consistent across the gradient, cypress domes in high urban landscapes have > 80% fewer juveniles and significantly more encroachment of woody vegetation than cypress domes in natural landscapes. This indicates that urbanization is causing reduced recruitment of juvenile cypress and encroachment of other vegetation types is causing cypress populations in cypress domes to fail. My results indicate that cypress populations in cypress domes are likely to decline as they are unable to overcome the pressures of current and future urbanization.
