Characterizing suitable habitat for the largest remaining population of the threatened Florida scrub-jay Aphelocoma coerulescens

Ke Miller,Cp Shea

doi:10.3354/esr01128

Abstract

Birds that breed in early-successional shrubland habitats are declining throughout North America. The Florida scrub-jay Aphelocoma coerulescens depends on Florida scrub, a shrubland plant community endemic to peninsular Florida, USA. The Florida scrub-jay is nonmigratory, federally listed as threatened, globally listed as Vulnerable, and experiencing ongoing population declines. The largest remaining population occurs in Ocala National Forest (Ocala NF), where the effects of intensive management of scrub for forest product extraction are unknown. During 2011-2014, we conducted the first quantitative evaluation of Florida scrub-jay density and productivity at Ocala NF in relation to the age, size, and connectivity of early-successional habitat patches. Regenerating clearcut stands 3-10 yr post-harvest provided suitable habitat conditions for Florida scrub-jays, with the maximum number of family groups and juveniles occurring in stands 6.5 and 7.4 yr post-harvest, respectively. Our findings indicate that previous definitions of suitable habitat for the species in Ocala NF (e.g. 0-20, 3-15, 3-12 yr post-harvest) are overly broad. We suggest that managers define suitable habitat conservatively given that few stands >10 yr post-harvest were occupied by scrub-jays, and annual productivity in those stands was relatively low. Our findings that scrub-jays readily occupied small scrub patches and did not avoid forested edges should be interpreted with caution, and more demographic study is needed to understand survival and dispersal among patches. Managers can maximize Florida scrub-jay populations in Ocala NF by increasing the availability of habitat that is within 3-10 yr post-harvest.

Highlights

Birds that breed in early-successional shrubland habitats are declining more rapidly than most bird species in North America (Hunter et al 2001, Dettmers 2003), and quantifying and managing suitable habitat for these species is critically important
The Florida scrub-jay Aphelocoma coerulescens is a habitat-restricted endemic species that continues to decline because of habitat loss, habitat fragmentation, and management challenges related to firemaintained early-successional habitat
The Florida scrub-jay is listed as threatened by the US Fish and Wildlife Service (USFWS 1987) and Vulnerable by the International Union for the Conservation of Nature (IUCN; Handbook of Birds of the World and BirdLife International 2018) but could be reclassified by the IUCN as Endangered if human development continues to degrade and eliminate its habitat (BirdLife International 2000)

Summary

Introduction

Birds that breed in early-successional shrubland habitats are declining more rapidly than most bird species in North America (Hunter et al 2001, Dettmers 2003), and quantifying and managing suitable habitat for these species is critically important. The Florida scrub-jay Aphelocoma coerulescens is a habitat-restricted endemic species that continues to decline because of habitat loss, habitat fragmentation, and management challenges related to firemaintained early-successional habitat. The Florida scrub-jay is listed as threatened by the US Fish and Wildlife Service (USFWS 1987) and Vulnerable by the International Union for the Conservation of Nature (IUCN; Handbook of Birds of the World and BirdLife International 2018) but could be reclassified by the IUCN as Endangered if human development continues to degrade and eliminate its habitat (BirdLife International 2000). Recent surveys indicate Florida scrub-jay populations continue to decline on many public conservation lands, with lack of earlysuccessional scrub believed to be the primary cause (USFWS 2007, Boughton & Bowman 2011)

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