Habitat Fragmentation in Small Vertebrates from the Sonoran Desert in Baja California

Persistent Link:
http://hdl.handle.net/10150/205423
Title:
Habitat Fragmentation in Small Vertebrates from the Sonoran Desert in Baja California
Author:
Munguia-Vega, Adrian
Issue Date:
2011
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Embargo:
Embargo: Release after 12/05/2012
Abstract:
Land conversion is one of the greatest threats to terrestrial ecosystems around the world, and understanding its impacts on the biota is crutial for the management and conservation of species in and around human-modified landscapes, particularly in those where local declines can quickly translate into the extinction of endemic species or Evolutionary Significant Units.I investigated how habitat loss and fragmentation impacted dispersal and extinction risk in three small vertebrates (a phrynosomatid lizard Urosaurus nigricaudus, and two heteromyid rodents Chaetodipus arenarius and Dipodomys simulans), in a highly fragmented agricultural valley from the Sonoran Desert in the Baja California Peninsula, Mexico, where reptiles and rodents show high endemism and phylogenetic diversity. After reconstructing the history of habitat loss at the valley during the last 60 years, my approach involved the development and genotyping of 10 DNA microsatellite loci in 800 individuals from the three species that were sampled from continuous and fragmented habitat and analyzed using various population genetic methods.Although genetic diversity was not significantly affected by habitat loss and fragmentation, I observed an increase in genetic structure, relatedness, the spatial scale of individual movement and reversal of sex-biased dispersal in the three species, compared to continous habitat. I found evidence of a large and spatially localized extinction debt in the lizard, that showed individual dispersal restricted to<400 m in the fragmented habitat, while the two heteromyids seemed capable of dispersing over distances of few kilometers. Several observations supported a higher extinction risk in kangaroo rats compared to pocket mice. Continuous areas surrounding the fragmented landscape where identified as important sources of individuals to habitat fragments located nearby. Even the vegetation associated with a narrow wash across the fragmented landscape appeared to act as a corridor as high levels of dispersing individuals were inferred in the three species over a scale of several kilometers. This study provided an approach to evaluate the effects of distinct landscape features in preventing or allowing individual dispersal in multiple co-distributed species towards their conservation in human-modified landscapes.
Type:
text; Electronic Dissertation
Keywords:
extinction; fragmentation; habitat; microsatellite; Natural Resources; desert; dispersal
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Natural Resources
Degree Grantor:
University of Arizona
Advisor:
Culver, Melanie

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleHabitat Fragmentation in Small Vertebrates from the Sonoran Desert in Baja Californiaen_US
dc.creatorMunguia-Vega, Adrianen_US
dc.contributor.authorMunguia-Vega, Adrianen_US
dc.date.issued2011-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.releaseEmbargo: Release after 12/05/2012en_US
dc.description.abstractLand conversion is one of the greatest threats to terrestrial ecosystems around the world, and understanding its impacts on the biota is crutial for the management and conservation of species in and around human-modified landscapes, particularly in those where local declines can quickly translate into the extinction of endemic species or Evolutionary Significant Units.I investigated how habitat loss and fragmentation impacted dispersal and extinction risk in three small vertebrates (a phrynosomatid lizard Urosaurus nigricaudus, and two heteromyid rodents Chaetodipus arenarius and Dipodomys simulans), in a highly fragmented agricultural valley from the Sonoran Desert in the Baja California Peninsula, Mexico, where reptiles and rodents show high endemism and phylogenetic diversity. After reconstructing the history of habitat loss at the valley during the last 60 years, my approach involved the development and genotyping of 10 DNA microsatellite loci in 800 individuals from the three species that were sampled from continuous and fragmented habitat and analyzed using various population genetic methods.Although genetic diversity was not significantly affected by habitat loss and fragmentation, I observed an increase in genetic structure, relatedness, the spatial scale of individual movement and reversal of sex-biased dispersal in the three species, compared to continous habitat. I found evidence of a large and spatially localized extinction debt in the lizard, that showed individual dispersal restricted to<400 m in the fragmented habitat, while the two heteromyids seemed capable of dispersing over distances of few kilometers. Several observations supported a higher extinction risk in kangaroo rats compared to pocket mice. Continuous areas surrounding the fragmented landscape where identified as important sources of individuals to habitat fragments located nearby. Even the vegetation associated with a narrow wash across the fragmented landscape appeared to act as a corridor as high levels of dispersing individuals were inferred in the three species over a scale of several kilometers. This study provided an approach to evaluate the effects of distinct landscape features in preventing or allowing individual dispersal in multiple co-distributed species towards their conservation in human-modified landscapes.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectextinctionen_US
dc.subjectfragmentationen_US
dc.subjecthabitaten_US
dc.subjectmicrosatelliteen_US
dc.subjectNatural Resourcesen_US
dc.subjectdeserten_US
dc.subjectdispersalen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineNatural Resourcesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorCulver, Melanieen_US
dc.contributor.committeememberRodriguez-Estrella, Ricardoen_US
dc.contributor.committeememberNachman, Michael W.en_US
dc.contributor.committeememberShaw, William W.en_US
dc.contributor.committeememberCulver, Melanieen_US
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