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Understanding species -habitat relationships is fundamental to the conservation of
a species . This is especially important when the species is considered endangered . The
Golden -cheeked Warbler is a habitat specialist that breeds only in oak -juniper
woodlands (considered a climax forest ) of central Texas . The warbler was listed as
endangered under the federal Endangered Species Act primarily because of habitat loss
and fragmentation . Conservation measures include the preservation of existing habitat
and attempts to manage and enhance areas that once supported the warbler to return to
the climax oak -juniper woodlands . My objectives were (1 ) to quantify the vegetation
structure and species composition by vegetation volume of occupied warbler habitat
across the breeding range in Texas and (2 ) to quantify the habitat use by the warbler in
categories of behavior , substrate , height , and tree species . Instantaneous , focal animal
behavioral observations were collected for three breeding seasons at six sites across the
range of the warbler . Warbler behavior and microhabitat use were compared to
availability of vegetation volume by height class and tree species . I found that Goldencheeked
Warbler habitat varied by vegetation volume , canopy height and tree species among all sites . The warbler preferred twigs and foliage and the upper two height
classes of the habitat structure for all behaviors . Tree species use did not match
availability at any sites . The one consistent species result was the warbler used Ashe
juniper significantly less than it occurred at all sites . Other major species were used
disproportionately to the species occurrence at each site . Some tree species were used
more often than they occur in the habitat while others species were used less than they
occur in the habitat . Preferences for height class and tree species use were not
significantly influenced by vegetation volume . Some other factor not measured such as
prey availability may be the cause . Because warbler habitat characteristics and use vary
across the range , any efforts to manipulate vegetation to become habitat must consider
regional characteristics of Golden -cheeked warbler habitat . |
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