Correlating demographic vital rates and population viability with climate conditions in Tobusch fishhook cactus

Tobusch fishhook cactus (Sclerocactus brevihamatus ssp. tobuschii) is a perennial cactus endemic to the Edwards Plateau of Texas. Habitat loss, habitat degradation, insect herbivory, and extreme climatic events threaten the conservation of this rare and endangered species. We used demographic data to assess population viability, correlate vital rates with climatic conditions and biotic factors, and to predict how population viability will be affected by climate change. Demographic and climate data from 11 sites and up to two decades were included in our analyses. We predict declines in most populations of Tobusch Fishhook Cactus. Past rapid declines were usually associated with the prevalence of herbivory by an undescribed weevil. There is some evidence of correlation of vital rates with annual temperature and precipitation. Thus, modeling future climate concurrently with population dynamics may be a more useful strategy for accurate assessing predictions of future population growth. Our work clarifies which populations are most likely to persist in the future and how future emissions scenarios affect the evaluation of each population.