This project investigates the genetic consequences of being an extreme ecological specialist in a rare and vanishing habitat. The Florida Scrub Jay is a federally Threatened bird species, restricted to a habitat that is rapidly being eliminated by man. Twenty-two years of detailed study of a marked population have shown that these jays have an unusual social system, and rarely move more than a few territories from where they were hatched. This very limited dispersal may result in rapid development of genetic changes over short distances, especially within a habitat that is highly fragmented. A variety of sophisticated genetic techniques (DNA 'fingerprinting' and sequencing) will be used to examine genetic variation at both local and regional scales. Specific goals are to: 1) confirm that reproduction takes place only by the mated pair on each territory (i.e., extra-pair or extra-territorial fertilizations are rare or absent); 2) test whether levels of inbreeding affect lifetime reproductive performance; 3) compare the effects of distance, degree of habitat isolation, and population size on genetic variation and differentiation, and 4) test whether these genetic effects match those predicted by long-term demographic data. Besides its theoretical applications, this study will further the protection of biodiversity by showing how habitat loss and fragmentation affect the genetic makeup of ecologically specialized species.
