Tuesday, August 7, 2007

PS 30-115: Estimating effects of the exotic Eurasian Collared-Dove (Streptopelia decaocto) on native doves in south Florida

Mark W. Miller, University of Florida, Elise V. Pearlstine, University of Florida, James E. Hines, USGS Patuxent Wildlife Research Center, and Frank J. Mazzotti, University of Florida.

The Eurasian Collared-Dove, Streptopelia decaocto, an abundant and aggressive exotic species, colonized North America via the Bahamas in the 1970s.  This dove could potentially compete with native dove species for breeding habitat.  Competition hypothesis predicts that distributions of Eurasian Collared-Doves and other dove species are not independent.  Area occupied by each of four dove species was estimated in two habitats in South Florida during 7 March – 26 May 2006.  We recorded presence/absence data for each species in 103 urban sites in Fort Lauderdale, Florida and in 45 sites in sugarcane fields in the Everglades Agricultural Area.  We visited each site four times. We used two-species percent area occupied models and Program SURVIV to estimate whether Eurasian Collared-Dove co-occurred with Mourning Doves, Zenaida macroura, White-winged Doves, Zenaida asiatica, and Common Ground Doves, Columbina passerina, less often than expected if all species distributions were independent.  Eurasian Collared-Doves were more widespread in urban habitat (PAOUrban = 0.81) than any other dove species and were rare in agricultural habitat.  Mourning Doves were equally widespread in all habitats (PAO = 0.50).  Common Ground Doves were largely restricted to the agricultural area (PAOEAA = 0.36) and White-winged Doves were only found in Fort Lauderdale (PAOUrban = 0.58).  Eurasian Collared-Doves and Mourning Doves co-occurred more often than expected if their distributions were independent, as did Eurasian Collared-Doves and White-winged Doves, inconsistent with the prediction of the competition hypothesis.  Although our analysis was strictly correlational, Eurasian Collared-Doves may not be impacting native doves.