| Suites of anthropogenic chemicals and human disturbances impact the physical parameters of aquatic ecosystems. As concern grows over the presence of these endocrine disrupting compounds (EDCs) in the environment, several bioindicators have been developed to assess wildlife and ecosystem response to the pollutants, including fish and benthic macroinvertebrates. While fish behavioural assays have been used extensively, they are often used under limited conditions, specifically with small populations and a narrow range of sex ratios. Because these population dynamics inherently alter the baseline of behaviours, I explored the effect of sex ratio on aggression, and if this shift in behaviour produces any fitness consequences by searching the available literature on relevant fish species. I also explore whether sex ratio has any impact on behaviour in the fathead minnow (Pimephales promelas), one of the most common model species in ecotoxicology.;Furthermore, I examined the effects of pollution runoff on the benthic macroinvertebrate community within an arid climate. Aquatic insect assemblages spanning multiple trophic levels were identified to the order or family level at 18 sites in the Verde River and three of its tributaries, Oak, West Clear, and Fossil Creeks. Subsequent analyses and metrics indicated that, contrary to my expectations, the benthic composition did not shift dramatically to a less diverse community of more pollution tolerant organisms in sites which were exposed to the highest contamination levels. However, the distinct decrease in diversity and presence of the intolerant Chironomidae at sites near the city of Cottonwood indicate that this area requires further investigation. The results of both studies included in this document may enhance our comprehension of experimental laboratory results to be applied to our understanding and management of population and community-level effects of EDCs. |
