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Examining The Relationship Between Mesohabitats And Freshwater Mussels In An East Texas River, Andrew R. Glen

Biology Theses

North America is home to 302 unionoid species, with approximately 53 occurring in Texas, and are considered one of the most imperiled group of organisms in North America. Several hypotheses have been proposed to explain the spatial distribution of mussels within a stream reach, but only certain hydraulic characteristics appear to be correlated with their distribution. Emerging evidence indicates that freshwater mussels may use flow refugia to remain embedded during high flow events. As the use of hydraulic variables to characterize mussel habitat becomes more widespread, it may be useful to implement sampling that captures these measures. One option may …

Biotic And Abiotic Drivers Of Plant Symbionts Determine Plant Performance, The Maintenance Of Diversity, And Response To Global Change, Jeremiah A. Henning

Doctoral Dissertations

Interactions among organisms regulate the structure and function of ecosystems and the response of ecosystems to global change. The outcome of species interactions is shaped by the partners involved in the interaction and the climate contexts of the systems in which they reside. Global change is altering the distributions of organisms as well as the climate contexts of the systems they reside within, shifting the biotic and abiotic factors shaping species interactions. Thus, predicting the response of ecosystem structure and function to global change remains unresolved. For my dissertation, I explored how the interactions among plants and their mutualistic communities …

Plant-Microbial Interactions Are Strong Determinants Of Plant Population And Community Dynamics, Y. Anny Chung 9485698

Biology ETDs

Plant-microbial interactions are ubiquitous and yet the consequences of these interactions on plant population and community dynamics are relatively unknown. Here, we used two different classes of plant-microbial interactions to examine their effects on key plant population and community characteristics such as commonness and rarity, competition and coexistence, as well as community stability.

Vertically-transmitted endophytes had stage-dependent effects on the population growth of two grass species Poa sylvestris and Poa alsodes, and generally increased host population growth rates. However, it was the intrinsic demographic advantage of P. sylvestris that allowed its population to grow at a much faster rate …

Zonation Pattern And Spatial Arrangement Of A Geukensia Granosissima Population In A Mixed Mangrove Forest Of Tampa Bay, Derrick Shane Hudson

USF Tampa Graduate Theses and Dissertations

Here I provide the first report on Geukensia granosissima patterns of abundance along a tidal gradient within a mixed mangrove stand located in Tampa Bay, Florida, USA. Specifically, I examined 1) the relationship between G. granosissima size and density with mangrove root type (e.g. prop root, pneumatophore), and of density within the intertidal zones; and 2) the possible role of predation in shaping the lower zonation patterns displayed. Transect surveys located along the lower and upper population limit boundaries were conducted every two months over a ten-month period. Variables measured include size distribution, density of mussels, above ground mangrove prop …