Assessing regional differences in predation of endangered species: Implications from Texas populations of the endangered star cactus (Astrophytum asterias)

• Published in: Journal of arid environments 2013-10, Vol.97, p.143-149
• Main Authors: Ferguson, Adam W., Strauss, Richard E., Strong, Anna W., Birnbaum, Sandra J., Poole, Jackie M., Janssen, Gena K., Williamson, Paula S.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Asterias; Astrophytum asterias; Biological and medical sciences; cacti and succulents; Echinodermata; Endangered species; Endangered Species Act; Fundamental and applied biological sciences. Psychology; herbivores; Herbivory; Insects; Invertebrates; mammals; Mortality; population size; Populations; predation; Recovery plan; Recovery plans; Regional; Stars; Synecology; Terrestrial ecosystems; Threat assessment; Wildlife conservation
• ISSN: 0140-1963; 1095-922X
• DOI: 10.1016/j.jaridenv.2013.05.018

Understanding threats to endangered species is one of the most critical components of implementing a successful recovery plan. For the endangered star cactus Astrophytum asterias, both mammalian and insect herbivory have been documented as a major threat to populations in Mexico. Herein, we focus on populations of A. asterias in Texas, examining how mortality threats differ from populations found in Mexico as well as among sites within Texas. Our study supports insect and mammalian herbivory as a major threat to A. asterias in Texas, with reductions in population sizes ranging between 16 and 54%. However, our study highlights that both regional and local differences can influence rates of mortality even in a range-restricted species such as A. asterias and highlights the need to assess threats at both of these levels for effective development and implementation of endangered species recovery plans. •Endangered species recovery plans require threat assessments across a species distribution.•Diversity of mammalian herbivores is greater than previously documented.•Mortality differs in distinct ways from adjacent Mexican populations.•Mortality differs among seasons, across sites, and among size classes.•Herbivory is great enough to induce local extirpations and population declines.