Drought as a potential cause of elevated pitcher mortality in Sarracenia purpurea.

Abstract

Understanding the effects of climate change-induced drought on ecological systems is crucial to any effort that hopes to mitigate the damage done to ecosystems as drought becomes increasingly prevalent. The purple pitcher plant, Sarracenia purpurea, is a carnivorous wetland species particularly susceptible to long bouts of dry weather due to its multi-fold reliance on an abundance of water. This makes Sarracenia purpurea a perfect indicator species that may increase our understanding of how drought will affect wildlife communities at risk of mortality due to a lack of moisture. During the spring of 2012, abnormally high pitcher mortality was noted in the population of S. purpurea at Grass Bay Preserve in Cheboygan County, Michigan. It was hypothesized that abnormally dry conditions in northern Michigan during the summer of 2011 may have caused this unusually heightened senescence of pitchers. In this study, 100 S. purpurea were selected to be our sample population. We took measurements of moisture availability, pitcher temperature, and plentitude of competitive root biomass for each of the 100 Sarracenia purpurea or, in some cases, a subset of 40 plants. We also took “pitcher mortality” measurements consisting of counting the number of dead pitchers, live pitchers, new pitchers, damaged pitchers, flowers, and diameter for each plant. We found no correlation between moisture availability and pitcher mortality, suggesting an optimistic outlook for wetland plant species if current levels of drought frequency and intensity are sustained.