Print PageHabitat loss and fragmentation of Florida’s oak scrub habitat has resulted in smaller and increasingly isolated populations of the Florida Scrub-Jay (Aphelocoma coerulescens). Florida Scrub-Jays are dependent on frequently burned scrub, but prescribed fire is often at odds with surrounding human land uses. A survey of scrub-jays in 1992-1993 concluded that populations had declined by more than 40% from the previous decade. As a consequence, acquisition and protection of scrubs became a priority and 198 sites are currently under conservation management. Because no subsequent statewide survey of scrub-jay populations existed, in 2009-2010, we compiled surveys conducted by others and undertook our own surveys to examine population trends since 1992-93. We used current habitat delineations to estimate jay carrying capacity for all sites.
Results/Conclusions
Despite an increase in the area of protected lands, scrub-jay populations declined by more than 20%. Excluding 20 managed areas where no data were available from the 1992-1993 survey, jay populations declined by at least 1 group at 95 sites, remained the same at 37 sites, and at 46 sites increased by at least 1 group. A total of 54 managed areas which contained at least one FSJ group in 1992-1993 had been extirpated by 2009-2010. The vast majority of these had consisted of only a single FSJ group in 1992-93 and 49 (90.7%) consisted of fewer than five groups. However, two populations that consisted of at least 10 groups in 1992-93 were extirpated by 2009-10. The current population of 1253 groups on managed lands is less than half the potential carrying capacity of 3094 groups. Continued declines and the frequency of populations below carrying capacity on conservation lands are due to inadequate fire management. Increased fire management is critical for the species survival. Recent genetic analysis identified 10 distinct genetic populations separated by geographic barriers: rivers, estuaries, and large expanses of non-jay habitat, such as forests. The carrying capacity of genetic units based on currently managed lands ranged from 22 – 1092 groups. The percent of carrying capacity currently reached for the genetic units ranges from 18.2% - 95.7%. Without immediate rescue efforts, the probability of distinct genetic populations being lost in this Threatened species is very high. We propose a hierarchical management approach based on genetic unit, habitat delineated core population regions, and current distributions of jays, to focus management efforts to achieve population recovery for each of the ten genetic units.
