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Ecology and Evolutionary Biology Commons

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Full-Text Articles in Ecology and Evolutionary Biology

Nitrogen Pulses And Competition Between Native And Invasive Plant Species, Nicolas Matallana, Mandy L. Slate, Ragan M. Callaway Jan 2017

Nitrogen Pulses And Competition Between Native And Invasive Plant Species, Nicolas Matallana, Mandy L. Slate, Ragan M. Callaway

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Variation in the timing and size of resource fluctuations can influence how plants grow, allocate biomass, and reproduce. Resources are sometimes made available in relatively continuous, reliable pulses while other times they are temporally separated and unpredictable. Native and invasive plant species are thought to respond differently to resource fluctuations, or pulses, which can influence competitive outcomes. The “Fluctuating Resource Hypothesis” predicts that resource fluctuations benefit invasive species more than native species, potentially because many invaders are highly effective at rapidly capturing resources. In a field setting, we examined the effects of varying nitrogen pulses on competition between exotic invasive …


Wolf-Cougar Co-Occurrence In The Central Canadian Rocky Mountains, Ellen Brandell Jan 2015

Wolf-Cougar Co-Occurrence In The Central Canadian Rocky Mountains, Ellen Brandell

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Cougars and wolves are top carnivores that influence the dynamics of an ecosystem, including prey behavior and dynamics, and interspecific competition. Studies about the interactions between wolves and cougars typically find wolves are dominant competitors to cougars. We examined single-species, single-season occupancy models and co-occurrence models of wolves and cougars in the Central Canadian Rocky Mountains to understand interactions between these two species on a grand landscape. Data was collected from 2012-2013 using remote wildlife cameras and separated into seasons. Naïve occupancy estimates were larger for wolves in both seasons, but both species had smaller ranges in winter. There were …


Morphological Variability In Tree Root Architecture Indirectly Affects Coexistence Among Competitors In The Understory, Erik T. Aschehoug, Ragan M. Callaway Jul 2014

Morphological Variability In Tree Root Architecture Indirectly Affects Coexistence Among Competitors In The Understory, Erik T. Aschehoug, Ragan M. Callaway

Biological Sciences Faculty Publications

Interactions between plants can have strong effects on community structure and function. Variability in the morphological, developmental, physiological, and biochemical traits of plants can influence the outcome of plant interactions and thus have important ecological consequences. However, the ecological ramifications of trait variability in plants are poorly understood and have rarely been tested in the field. We experimentally tested the effects of morphological variation in root architecture of Quercus douglasii trees in the field on interactions between understory plants and community composition. Our results indicate that variability among Q. douglasii tree root systems initiates a striking reversal in the competitive …