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Climate change

2016

All Graduate Theses and Dissertations

Articles 1 - 2 of 2

Full-Text Articles in Life Sciences

Rapid Savanna Response To Changing Precipitation Intensity, Ryan S. Berry May 2016

Rapid Savanna Response To Changing Precipitation Intensity, Ryan S. Berry

All Graduate Theses and Dissertations

As the atmosphere warms, precipitation events are likely to become less frequent but more intense. While extensive efforts have been made to understand how changes in mean annual precipitation will affect plant growth, particularly in semi-arid systems, relatively little is known about how increasing precipitation intensity will affect plant growth and hydrologic cycles. A recent study by Kulmatiski and Beard (2013) found that small increases in precipitation intensity increased woody plant growth and decreased grass growth in a three-year experiment in a savanna system, Kruger National Park. Here we report results from the following two years of that experiment. Due ...


A Spatiotemporal Mountain Pine Beetle Outbreak Model Predicting Severity, Cycle Period, And Invasion Speed, Jacob P. Duncan May 2016

A Spatiotemporal Mountain Pine Beetle Outbreak Model Predicting Severity, Cycle Period, And Invasion Speed, Jacob P. Duncan

All Graduate Theses and Dissertations

The mountain pine beetle (MPB, Dendroctonus ponderosae), a tree-killing bark beetle, has historically been part of the normal disturbance regime in lodgepole pine (Pinus contorta) forests. In recent years, warm winters and summers have allowed MPB populations to achieve synchronous emergence and successful attacks, resulting in widespread population outbreaks and resultant tree mortality across western North America. We develop an age-structured forest demographic model that incorporates temperature-dependent MPB infestations: the Susceptible-Infested-Juvenile (SIJ) model. Stability of fixed points is analyzed as a function of population growth rates, and indicates the existence of periodic outbreaks that intensify as growth rates increase. We ...