Short term climatic rescue of an endangered species? The interactive effects of climate and a pathogen on the demography of Menzies' wallflower
Results/Conclusions: This inter-annual variation in demography was predicted to cause population growth rates to vary from nearly 50% yearly reductions to 90% yearly increases. This variation in demographic rates was strongly correlated with deviations in seasonal temperatures from the historical averages. Notably, survival and growth of small-leafed individuals was lower in warmer non-winter seasons, and fecundity of flowering individuals was lower in years with warmer January to March temperatures. This latter correlation coincided with greater severity of white rust disease during years with warmer to January to March temperatures. Due to these correlates between temperature and demography, the models predicted that warmer seasons lead to lower population growth rates. While temperatures in this area exhibited a warming trend over the past century, there was a strong Pacific Decadal Oscillation signal around this trend. The warmest years, 1988 and 1992, occurred at the time Menzies' wallflower was listed as an endangered species. According to our model, warmer temperatures near this period were predicted to cause significant population declines. Since 1992, there has been a multi-decadal cooling trend which the models predicted would promote positive population growth consistent with population surveys from 1988 to 2006.