Bats across an Urban-rural gradient
CURRENT STUDENT: SHANNON PEDERSON
Urbanization’s effect (without WNS impact) on bat activity and diversity in Calgary, Chicago, Detroit, Indianapolis, Mexico City, Ontario, Panama, and European and Australian cities have been studied and resulted in mixed conclusions. Some studies have concluded that urbanization decreased bat activity and diversity (Hale et al. 2012, Threlfall et al. 2011, Hourigan et al. 2006, Gaisler et al. 1998, Kurta and Teramino 1992), whereas others have indicated that urbanization increased bat activity (Coleman and Barclay 2012, Jung and Kalko 2010, Avila-Flores and Fenton 2005, Gehrt and Chelsvig 2004, Walsh and Harris 1996), or only had minimal change on diversity (Mendes et al. 2014, Hourigan et al. 2010, Lesinski et al. 2000).
One large bat survey (using acoustic and capture techniques) was conducted at National Parks in Washington, DC, and surrounding states that represented different levels of urbanization and forest fragmentation (Johnson et al. 2008). This study reported that forest fragmentation had a greater impact on species diversity and activity than urbanization alone, but overall, urban parks had lower bat species diversity than rural parks. However, this survey occurred before WNS.
WNS was confirmed in Virginia in 2009 (VADGIF 2009), Maryland in 2010 and Delaware in 2012. Interestingly, the role of urbanization, which would create warmer climates due to the heat island effect, in WNS positive areas has not been investigated. Research on bat activity post-WNS lacks information on the influence of urbanization; therefore, our research is focusing on the following questions:
Do bats utilize highly urbanized areas? Do moderately urbanized areas surrounded by highly urbanized areas serve as reservoirs?
Will certain bat species exhibit differences in activity and composition in highly urbanized areas?
Can we predict which, if any, landscape features or combination of features is important to WNS sensitive species and remnant species along an urban-rural gradient?