| dc.description.abstract | Climate change is affecting marine environmental conditions which can affect fish distributions, survival, and species interactions. The aim of this dissertation is to address how climate change may affect fish populations and community dynamics, using Texas as a study system. To address this issue, I first estimate a time series of fish species diversity, for spring and fall, in each of the eight major bays of Texas, and model diversity as a function of abiotic variables. I show that fish diversity has increased through time, and is significantly associated with climate-related variables. Next, I investigate impacts on populations of three abundant coastal species in Texas, Atlantic croaker (Micropogonias undulatus), black drum (Pogonias cromis), and spotted seatrout (Cynoscion nebulosus). I estimate a time series mortality rate for each species, and model mortality as a function of abiotic and biotic factors. I show that species diversity, temperature, salinity, and dissolved oxygen are significantly related to mortality and that increasing species diversity negatively impacts survival, likely due to competition and predation from expanding species. Finally, I investigate impacts on functional composition and diversity. I estimate two metrics of functional diversity through time and community weighted functional trait means to identify functional consequences of changing biodiversity. Additionally, I estimate interactions between commonly occurring and geographically expanding species using generalized additive models. I show that functional richness has increased, while functional dispersion has decreased (spring) or remained stable (fall), and that the assemblages are becoming more functionally homogeneous, with increasing abundance of long-lived, large, and higher in trophic level species. My research provides insight into climate effects on marine communities of Texas, and the results will be important for future conservation and management of the coastal ecosystems of Texas. | en |
