Habitat relationships of seven breeding bird species in the Leon River Watershed investigated at local scales

Show simple item record

dc.contributor.advisor Wilkins , R . Neal en_US
dc.contributor.committeeMember Smeins , Fred en_US
dc.creator Juarez Berrios , Edwin Alfredo en_US
dc.date.accessioned 2005 -02 -17T21 :06 :02Z
dc.date.accessioned 2014 -02 -19T19 :19 :42Z
dc.date.available 2005 -02 -17T21 :06 :02Z
dc.date.available 2014 -02 -19T19 :19 :42Z
dc.date.created 2004 -12 en_US
dc.date.issued 2005 -02 -17T21 :06 :02Z
dc.identifier.uri http : / /hdl .handle .net /1969 .1 /1574
dc.description.abstract Over the past 100 ?150 years Texas rangelands have dramatically changed from native open savannahs to dense woodlands . On the Edwards plateau , a major management concern is the increasing encroachment of Ashe juniper (Juniperus ashei ) . Preceding an anticipated brush management program , I investigated the presence , co -occurrence , and habitat relationships of 7 breeding bird species in the Leon River Watershed in central Texas , USA : black -capped vireo (Vireo atricapillus ) , golden -cheeked warbler (Dendroica chrysoparia ) , northern bobwhite (Colinus virginianus ) , white -eyed vireo (Vireo griseus ) , Bell ?s vireo (Vireo bellii ) , painted bunting (Passerina ciris ) , and brown -headed cowbird (Molothrus ater ) . Vegetation characteristics were compared between sites occupied by each species and unoccupied sites using univariate analysis . Models for predicting species site occupancy were developed (using logistic regression ) based on habitat characteristics correlated with the presence of each species . Two species of special concern , the endangered black -capped vireo and golden -cheeked warbler occupied 5 .6 % of sites and 13 .8 % of sites respectively , while the brood parasite brown -headed cowbird was the most widespread , occupying 86 .8 % of sites . Species co -occurrence patterns revealed significant associations between the golden -cheeked warbler and each of 5 other species . For most species , variables included in habitat models could be explained by knowledge of species known habitat associations . For example , the black -capped vireo was positively associated with increasing low -growing ( <1 .5 m ) hardwood cover and with Low Stony Hill ecological sites . The golden -cheeked warbler was positively associated with increasing density of larger juniper trees , increasing variability in vertical vegetation structure , and decreasing midstory canopy of deciduous nonoaks (e .g . , cedar elm [Ulmus crasifolia] ) . It also preferred Low Stony Hill and Steep Adobe ecological sites . Site occupancy seemed to be driven by variables that describe overall vegetation structure . In particular , cover of low -growing non -juniper vegetation and juniper tree density appeared to be important in determining site occupancy for several species . Although the models constructed were not very robust , resource managers can still benefit from such models because they provide a preliminary examination of important controlling variables . Managing rangelands to maintain or restore a mosaic of juniper patches and open shrublands are likely to help meet the habitat requirements of these bird communities . en_US
dc.format.extent 1633306 bytes
dc.format.medium electronic en_US
dc.format.mimetype application /pdf
dc.language.iso en _US en_US
dc.publisher Texas A &M University en_US
dc.subject Ashe juniper en_US
dc.title Habitat relationships of seven breeding bird species in the Leon River Watershed investigated at local scales en_US
dc.type Book en
dc.type.genre Electronic Thesis en_US
dc.type.material text en_US
dc.format.digitalOrigin born digital en_US


Habitat relationships of seven breeding bird species in the Leon River Watershed investigated at local scales. Available electronically from http : / /hdl .handle .net /1969 .1 /1574 .

Files in this item

Files Size Format View

There are no files associated with this item.

This item appears in the following Collection(s)

Show simple item record

Search DSpace

Advanced Search