Life Sciences Commons^™

From Second Creek To New Pangea: A Multi-Scale Analysis Of Patterns And Trends In Aquatic Biodiversity, Jeffrey Robert Duncan

Doctoral Dissertations

The Earth’s freshwater ecosystems are undergoing a period of dramatic change. The simultaneous expansion and contraction of aquatic species’ ranges is leaving an indelible mark on the evolutionary histories of the world’s freshwater species. This dissertation represents a compilation of research efforts that quantify, explain, and propose policy recommendations concerning current trends in aquatic biodiversity. Part II provides an appraisal of the status of the world’s freshwater fishes that asks two primary questions—are all taxonomic groups equally susceptible to extinction, and can we identify a unifying suite of extinction risk factors? Although I concluded, that extinction risk is not randomly …

Anthropogenic Impacts On Riparian Forest Loss In East Tennessee: A Gis Analysis, Karen Burhenn

Masters Theses

Streamside, or riparian, areas are vital components of a healthy watershed system. Natural riparian areas perform multiple ecosystem functions including filtering sediments and pollutants from upland areas, stabilizing banks and floodplains, regulating stream temperatures, and providing habitat for many native and migratory species. In eastern Tennessee, natural riparian forests have declined by 40 to 60 percent (SAMAB 1996b). I examined the spatial distribution of humans and their land-cover changing activities in an effort to contribute to a better understanding of the loss of riparian forests in the eastern Tennessee region.

This research is centered in the Central Ridge and Valley …

Markov Set-Chains As Models Of Plant Succession, Corey L. Samuels

Doctoral Dissertations

In this dissertation I examine Markov set-chains as a new approach for modeling plant succession. Set-chains are an extension of Markov chains, due to Hartfiel (1991, 1998), that makes it possible to model succession when transition probabilities are uncertain or fluctuating. In Markov set-chains each transition probability is expressed as an interval containing the range of all possible values for that parameter. In turn, a set-chain predicts community composition as a range of possible frequencies for each species. First, I give an introduction to Markov set-chains and methods for iterating and finding their asymptotic behavior. I demonstrate the formulation and …

Markov Set-Chains As Models Of Plant Succession, Corey L. Samuels

Doctoral Dissertations

In this dissertation I examine Markov set-chains as a new approach for modeling plant succession. Set-chains are an extension of Markov chains, due to Hartfiel (1991, 1998), that makes it possible to model succession when transition probabilities are uncertain or fluctuating. In Markov set-chains each transition probability is expressed as an interval containing the range of all possible values for that parameter. In turn, a setchain predicts community composition as a range of possible frequencies for each species. First, I give an introduction to Markov set-chains and methods for iterating and finding their asymptotic behavior. I demonstrate the formulation and …