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

Niche breadth and the implications of climate change in the conservation of the genus Astrophytum (Cactaceae)

“…Additionally, we used the records of studied populations by Mandujano, Golubov and Martínez-Avalos, and in the particular case of A. asterias in Texas, we used Google Earth to obtain the approximate location of sites, on the basis of the information provided in several studies (Weniger, 1970;USFWS, 2003;Terry, 2005;Strong and Williamson, 2007;Terry et al, 2007;Janssen et al, 2010;Ferguson et al, 2013). Because modeling was intended at the population level, we made a depuration of georeferences by determining the geographic coordinates of central points between sites separated by less than 500 m (potentially recurrent records within populations) and by excluding references without values of seconds when these were separate from other references by less than two km (i. e. 1 min).…”

“…Unfortunately, although some studies have been focused in the reproduction, pollination, herbivory and demography of Astrophytum species (Martínez-Avalos et al, 2007;Strong and Williamson, 2007;Blair and Williamson, 2008;Ferguson et al, 2013;Zepeda-Martínez et al, 2013), with exception of last cited study, the others have been made with A. asterias, and the systematic records of ecological data from populations through the time, which could allow to analyze potential relationships between climatic alterations and changes in characteristics of the life cycle, are absent in the literature. However, on the basis of the evidence provided by long-time records about the effects of climate change in the phenology of several plant species (e. g., Peñuelas et al, 2002;Miller-Rushing and Primack, 2008), and the projections suggesting the loss of the overlap between the flowering time in plants and the abundance peak of their pollinators as consequence of the increase in temperature (e. g., Memmott et al, 2007), we expect consequences of climate change in the reproduction of Astrophytum, due to the alterations in the predominant regimes of temperature and precipitation in the reproductive period across their distribution areas (changes in bioclimatic variables for the driest and wettest quarters), but these aspects need further evaluation.…”

“…Avalos et al, 2004Avalos et al, , 2007Ferguson et al, 2013), and that the climate change only may represent the "straw that broke the camel's back" by eliminating the chances for the natural regeneration of populations and by reducing the successful probabilities of reintroduction programs like those implemented in A. asterias (Birnbaum et al, 2011). So, the efforts to the conservation of Astrophytum species, like to many other threatened species of commercial interest, must include a combination of additional strategies as the elimination of legal loopholes that facilitate the species illegal trade (B arcenas, 2006), the promotion of more conservation areas, and urbanization projects ecologically sustainable.…”

“…Besides natural factors, such as the predation by insects and mammals, populations of Astrophytum species (Cactaceae) are highly threatened by illegal extraction and the destruction of their habitats (Hern andez and B arcenas, 1995;Martínez-Avalos et al, 2004, 2007Ferguson et al, 2013), and potential effects of climate change remain unknown. We estimated the niche breadth of Astrophytum species using the macro-environmental characteristics in the set of populations, and using measures of the use of local habitat in the area occupied by two relatively conserved populations of each species, in order to analyze whether species with widest niche breadths are less prone to experience unsuitable conditions under climate change, and to examine implications of climate change in the conservation of Astrophytum.…”

Growth and demography of a declining, endangered cactus in the Sonoran Desert

“…In the near term, this factor may be the most important short‐term threat to this population. To explore this further, we have established additional study plots in nearby areas where observations of scat indicate that sheep are less common, with the aim of providing a complementary perspective during coming decades (e.g., Ferguson et al, ).…”