Off-campus UMass Amherst users: To download campus access dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.

Non-UMass Amherst users: Please talk to your librarian about requesting this dissertation through interlibrary loan.

Dissertations that have an embargo placed on them will not be available to anyone until the embargo expires.

Author ORCID Identifier


Open Access Dissertation

Document Type


Degree Name

Doctor of Philosophy (PhD)

Degree Program

Environmental Conservation

Year Degree Awarded


Month Degree Awarded


First Advisor

John F. Organ

Second Advisor

Stephen DeStefano

Third Advisor

Todd K. Fuller

Fourth Advisor

Jason Kamilar

Subject Categories

Other Ecology and Evolutionary Biology


My dissertation aims to contribute to the knowledge of Andean bears in Peru. The Andean bear (Tremarctos ornatus) is the sole bear species in south America. The lack of knowledge on different aspects of Andean bear ecology, biogeography, and abundance patterns hinders current conservation efforts for the species. I compiled Andean bear occurrence records in Peru with collaboration from many colleagues and created an open-access database at the GBIF data repository. Next, I modeled the distribution of Andean bear within Peru and compared estimates including and excluding unpublished records. I found that models combining published and unpublished records estimated broader and more connected predicted occurrence areas than models that only included records from the published literature. Estimates were improved by using unpublished records because key data added from unsampled localities reduced spatial sampling bias. I used 15N stable isotopes analyses of hair samples to infer diet composition and trophic position for all eight bear species in the world by comparing bear 15N values to reference mammal species and to published dietary studies. I also examined how the frequency of reported human-bear conflicts related to bear trophic positions. I found that most bear species were mainly herbivorous (low15N) and similar, while the few more highly carnivorous species (high15N) differed among themselves in trophic position. At least one bear species ranged from herbivorous to carnivorous between sampling localities. The 15N signatures of bears were uncorrelated to the frequency of livestock predation or crop damage reported, indicating bear-human conflicts are not related to bear diet composition. Since undertaking effective conservation decisions and actions for broadly distributed species such as bears depends on large-scale information, individual efforts fall short in developing full understanding of conservation needs. Thus, I encourage the use and publication of raw data from opportunistic observations, reports of natural park rangers, student theses, and small independent studies to gain better knowledge particularly for poorly studied species. Also, similar diet patterns among bears suggests that techniques developed for dealing with human-bear conflicts for certain bear species can be applied to others as well, which could enhance bear conservation worldwide.