Black Grama (Bouteloua eriopoda) is a long-lived keystone primary producer across much of semi-arid southwestern North America. Though the ecology of this grass is relatively well studied, the potential effects of climate change on the species and ecosystem are more poorly understood. We examined size distribution and seed production of B. eriopoda following nine years of ongoing monsoon rainfall manipulation treatments. This Long Term Ecological Research (LTER) experiment is designed to imitate monsoon pulse precipitation patterns predicted by climate change models at Sevilleta National Wildlife Refuge, NM. Demographic measurements were collected in mid-June before the monsoon growing season began. Spikelets were collected once B. eriopoda florets went to seed in mid to late September. We found significantly higher mean tussock volume and height in plots with added precipitation compared to ambient control plots. Greater height was correlated with higher spikelet mass and average number of spikelets per inflorescence in long pulse treatment plots. This indicates an increase in reproductive fitness accompanying increased survival with less frequent, more intense rainfall. These findings shed light on how semiarid ecosystems may respond to shifting precipitation pulses in the Southwest with regards to a changing climate.
In the context of the important implications of climate change, this paper analyzes the impact of weather on wine quality and prices for premium wines in regions along the west coast of the United States. The aim of this research is to determine the most suitable areas for growing wine grapes in this area of the United States with expectations of a changing climate. This study uses a collection of wine data from Wine Spectator (9,650 observations) from 2005 to 2015 for Washington, Oregon, Sonoma, and Mendocino wine regions. Three Ordinary Least Squares regression models use ten weather variables including both average temperatures and precipitation to explain variation in wine quality ratings and release prices. The results suggest that the quality of Oregon wine, especially pinot noir, is benefitting the most from rising temperatures and increased rainfall. Oregon’s cool, wet climate provides the most optimistic outlook regarding climate change.
A series of rapid global warming events, triggered by the release of CO2, occurred at ~55.5 Ma. These events are called hyperthermals, and they have garnered a great deal of attention as probable analogs for present-day CO2 increase and climate change. The best known hyperthermal event is the PETM, which was followed by two smaller events called ETM2 and H2. Pedogenic carbonate nodules from the Bighorn Basin in Wyoming provide the first terrestrial records of ETM2 and H2. Since pedogenic carbonates precipitate out of the groundwater, the major and trace element composition of these nodules can be used as a proxy for groundwater conditions during ETM2 and H2. The ratios Na/K, Na/Al, K/Al and Mg/Al were used as weathering indicators. Boron was used as a proxy for pH, and Phosphorus was used as a proxy for plant activity. The redox sensitive elements Fe, Cu, Se, V, U Zn, and Ni were considered as proxies for soil saturation. Comparison of pre hyperthermal to mid hyperthermal groundwater chemistry indicates that (1) Weathering intensity and sedimentation rates decreased during ETM2 and H2 (2) soil and groundwater became more acidic during ETM2 and H2 (3) The acidification was primarily driven by increases in plant activity during ETM2 and (4) Average rainfall decreased during ETM2, but the hyperthermal was characterized by wet and dry cycles.
Amphibians are declining on a global scale, faster than any other taxonomic group. Although I am still unsure of the causes of many local declines, I have evidence that on a larger scale temperature and precipitation changes caused by climate change directly relate to broader amphibian disappearances. I aim to use past temperature and precipitation trends and amphibian distributions in California to predict future amphibian distributions. I use the Biomod2 package in R, along with CMIP5 climate layers and emissions scenarios to correlate amphibian distributions to climate, and predict a range of future possibilities for amphibians under different carbon emission scenarios. I hope to identify which species are most in danger of extirpation to hopefully direct future management initiatives to these species.
The National Park Service (NPS) manages over 84 million acres of public lands in the United States. Its landscapes include some of the most visually stunning and ecologically pristine areas of the country. The parks, monuments, wildernesses, and protected areas that encompass the NPS are largely protected from human development, but that does not mean they are immune from disturbance or damage. In the past, impacts to these landscapes were largely due to poor land use decisions, such as overgrazing by cattle and fire suppression. However, a new threat – global climate change – threatens to significantly disturb these pristine areas. The NPS faces a substantial challenge in formulating effective management strategies to mitigate the impacts of climate change. This thesis investigates the system-wide response by the NPS to climate change in two ways. First, a comprehensive review of environmental management strategies was explored, with a focus on responses that could be particularly effective in a directionally changing climate. Second, a series of interviews with NPS managers and scientific researchers was conducted in order to contextualize the unique challenges that individual parks face regarding climate change. Interview responses were then discussed alongside the literature findings in order to explore the NPS’ response to climate change. The thesis concludes with specific recommendations for how the NPS can improve its strategies to mitigate the impacts of climate change on its landscapes.
