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Wetland resources in South Florida are regulated at three redundant jurisdictional levels: local or municipal regulations set forth by many independent jurisdictions, State regulations derived directly from Florida Statutes, and Federal regulations promulgated primarily under the Clean Water Act. All three levels of government can have jurisdiction over projects that affect regulated wetland resources, yet inconsistent policies and standards remain and continue to confound regulators despite decades of intensive coordination efforts and a rapidly growing scientific research base. The size of a wetland mitigation area is of primary consideration when evaluating its perceived ecological value, although wetland mitigation areas constructed in developed areas are typically isolated and generally make use of similar designs regardless of wetland size. The Chironomidae (Order: Diptera) are the most diverse and abundant faunal taxon in all healthy freshwater bodies and are generally considered to be a reliable and effective ecological indicator. I conducted a preliminary comparison of chironomid communities between a suite of natural and artificial wetlands, and also evaluated the effect of wetland size on the community structure of the insect family Chironomidae. Using the Chironomid Pupal Exuviae Technique (CPET), collections of chironomid exuviae from a total of seven natural and artificial mitigation wetlands were compared across site groups and also correlated to recorded environmental conditions at each study site. Chironomid species assemblages at nearly all sites were dominated by Parakiefferiella coronata, comprising nearly 36% of all collected exuviae. Species assemblages from mitigation wetlands exhibited strong similarity to the aggregate species assemblage from all sites. A greater abundance of exuviae was collected from artificial sites than from natural sites, and species assemblages collected from natural sites were dissimilar from those collected from artificial sites. No statistically significant differences in community structure were detected between larger and smaller wetlands. Environmental site conditions between natural and mitigation sites generally varied greatest in conductivity and pH. No significant gradient was identified in environmental conditions or chironomid community structure across wetlands of different size. A minor seasonal gradient in TP concentrations was observed and site S6 was the most enriched site included in this study while site S1 exhibited high conductivity for the duration of the project. Differences between chironomid species assemblages collected from natural and artificial communities may be explained by the relatively static topography, more consistent substrate composition, and less diverse hydrophyte communities present in the natural sites which have generally reached a greater state of homeostasis. However, statistical tests generally support the null hypothesis. No statistically significant differences were detected between sites based on collected chironomid communities when grouped by wetland origin (artificial vs. natural) or size. Observed differences between communities sampled from natural and artificial wetlands support regulatory concerns that artificial wetlands may not sufficiently emulate natural systems and that a constructed wetland system may take generations, or even centuries to sufficiently mimic its natural counterpart. Mitigation design complexity does appear to provide a diversity of microhabitats favorable to a greater variety of chironomids. However, a lack of statistical significance may support assertions that mitigation sites are successfully replacing natural wetlands. Implementation of CPET-based community structure analyses requires intensive labor and expertise and is not practical for regulatory purposes, but can provide robust data for effective and detailed site analysis.

Grape root borer, Vitacea polistiformis (Harris), is an oligophagous pest of grapevines in the eastern USA. Neonates must burrow into the soil to find grape roots. In Virginia, larvae feed on roots for ~2 years, then pupate just beneath the soil surface. Emerging adults leave an empty pupal exuviae at the soil surface around the vine base. There was no relationship between weekly captures in pheromone traps and pupal exuviae counts, indicating that exuviae sampling is most appropriate to assess infestations. Exuviae sampling in Virginia vineyards revealed infestations that ranged from light to very heavy. Eighteen biotic and abiotic variables were measured and used in analyses that assessed their relative contributions to differences in exuviae density. Water holding capacity and clay/sand ratio were most strongly associated with pupal exuviae density; these variables were used to develop a model for predicting the extent of infestation of individual vineyards. The spatial distribution of pupal exuviae was characterized using non-spatial and geospatial techniques. Although the non-spatial method (Taylor's Power Law) indicated that exuviae showed an aggregated distribution in all blocks, spatial methods (variograms, SADIE) revealed aggregated distributions only in blocks with ≥ 0.5 pupal exuviae per vine. Independent pupal exuviae samples for population assessment in vineyards can be achieved using sampling points separated by >8.8 m. Combined results from geospatial analyses and the temporal distribution of pupal exuviae within years enabled the development of a practical and quantitative sampling protocol. Bioassays used to measure the behavioral response of larvae to host stimuli revealed that neonates were attracted to grape root volatiles. In soil column bioassays, larvae moved vertically and horizontally over distances of up to 120 cm and apparently perceived the presence of grape roots from a distance of 5 cm in soil. Results are discussed in relation to their potential implications for monitoring and managing grape root borer. / Ph. D.

Urbanization involves the conversion of natural areas to impervious surfaces, which can lead to an increase in the frequency and severity of flood events in cities. To mitigate flood risk, stormwater ponds are constructed to manage urban runoff. Stormwater ponds can also be colonized by wildlife, but their suitability as habitat is disputed due to potential toxicological risks. This study assessed the suitability of stormwater ponds as habitat for the bioindicators Odonata (dragonflies and damselflies) and determined environmental factors that impact their community structure. Odonata (adults, nymphs and exuviae) were sampled at 41 stormwater ponds and 10 natural reference ponds across the National Capital Region of Canada, with a subset of ponds sampled over four years (2015-2018). Plant communities, water quality and surrounding land cover were analyzed at each pond to determine their impacts on Odonata community structure. Overall, stormwater ponds had lower Odonata abundance and a greater variation in species richness and community structure compared to natural ponds but had comparable dragonfly reproduction rates. Plants were the most significant driver of Odonata communities, as stormwater ponds with a high richness of native wetland plants had higher Odonata abundance and community structures similar to natural ponds. Water quality was the second most important driver of Odonata communities with dragonflies showing greater sensitivity to urban contaminants than damselflies. While stormwater ponds had higher concentrations of trace elements than natural ponds (e.g. Ni, V, As), concentrations were generally below toxic levels for all elements except copper and chloride, the latter likely an input from winter road salting. Surrounding land cover was the least important factor affecting Odonata communities. In conclusion, this research demonstrated the importance of local-scale factors related to plants and water quality in sustaining Odonata communities and specifies recommendations for stormwater pond design and maintenance that enhance urban biodiversity.