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Full-Text Articles in Life Sciences
Examining The Relationship Between Climate And Seasonal Stream Thermal Regimes In A High Desert Ecosystem, Hannah Moore, Melody Feden
Examining The Relationship Between Climate And Seasonal Stream Thermal Regimes In A High Desert Ecosystem, Hannah Moore, Melody Feden
Scholars Week
Climate change is negatively affecting ecosystems around the world, and in the coming years, scientists predict that these changes will only intensify and accelerate. In the western mountains of North America, climate change projections predict elevated temperatures, reduced snowpack, and earlier snowmelt. Elevated air temperatures have the propensity to affect water temperatures in sensitive freshwater ecosystems. Temperature increases may cause streams to reach the upper thermal limit for many aquatic organisms, such as aquatic invertebrates and fish, and result in death or dispersal for these organisms. This makes the availability of cold-water refugia in streams that much more important for …
Can Omnivores Mediate The Effects Of Degradation?, Hannah Moore
Can Omnivores Mediate The Effects Of Degradation?, Hannah Moore
Scholars Week
Omnivores feed at multiple trophic levels and have large effects on community structuring and stability. The magnitude and direction of such effects, whether omnivores stabilize or destabilize communities, remains unresolved. Shifts in omnivore diet and trophic position may be of particular importance to community stability in degraded habitats, where resources are sparse. For example, omnivores may reduce the severity and duration of community responses to degradationby dampening the effects of any disturbance-mediated trophic cascade. The relatively simple food webs of freshwater systems are ideal for studying trophic ecology, and in the western U.S., streams are heavily degraded by overgrazing, beaver …
Predator Presence And Size Variation Alters Community Structure Through Multiple Trophic Cascades, Robin Baker, Howard Whiteman Ph.D.
Predator Presence And Size Variation Alters Community Structure Through Multiple Trophic Cascades, Robin Baker, Howard Whiteman Ph.D.
Murray State Theses and Dissertations
Predation plays a crucial role in shaping community structure and can initiate trophic cascades that can alter abundances across adjacent trophic levels. Recent research has suggested that variation among individual predators may have stronger effects on ecological dynamics than previously appreciated. Intraspecific variation within predators could lead to differential levels of top-down control with implications for trophic cascade strength. In this experiment, we manipulated the body size variation of predatory mole salamanders (Ambystoma talpoideum) within experimental mesocosms and monitored a suite of abiotic and biotic response variables. We predicted that predator populations with increased body size variation would …
Trophic Interactions And Niche Partitioning Within A Post-White-Nose Syndrome Temperate Bat Community, Macy Kailing
Trophic Interactions And Niche Partitioning Within A Post-White-Nose Syndrome Temperate Bat Community, Macy Kailing
Murray State Theses and Dissertations
The decline of cave-dwelling bats since the introduction of white-nose syndrome (WNS) to North America changed the way communities interact. Disease-mediated competition at the community level can influence the ability of imperiled species to recover because of competitive exclusion. In western Kentucky, tri-colored bats, Perimyotis subflavus, which are susceptible to WNS severely declined following WNS occurrence. During that same period, evening bats, Nycticeius humeralis, which are not susceptible to WNS increased markedly. To investigate the influence of WNS on community structure, the diets of sympatric tri-colored and evening bats were assessed. Guano was collected from evening (n=37) and …
Omnivore Density Affects Community Structure Through Multiple Trophic Cascades, Donald J. Benkendorf
Omnivore Density Affects Community Structure Through Multiple Trophic Cascades, Donald J. Benkendorf
Murray State Theses and Dissertations
Omnivores can dampen trophic cascades by feeding at multiple trophic levels, yet few studies have evaluated how intraspecific variation influences the effect of omnivores on community structure. The Speckled Dace (Rhinichthys osculus) is an omnivorous cyprinid that consumes algae and invertebrates and is abundant throughout the western United States. I sought to identify the effects of size and size structure on top-down control by dace and learn how these effects scaled with density. Dace were manipulated in a mesocosm experiment and resulting changes in invertebrate and algal communities and measures of ecosystem function were monitored. Omnivores affected experimental …