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Each chapter of this dissertation is intended to address a piece of the central hypothesis that complex, interacting biotic and abiotic filters drive community dynamics, including temporal synchrony between communities arising from distant propagule sources. In Chapter I, I examine the influence of three different synchrony metrics on measures of similarity between real and simulated time series, comparing methods for identifying clusters of more synchronous populations or communities, and revealing environmental drivers of those clusters. My results for this study indicate that wavelet analysis works best if the data have high frequency effects or high levels of noise. Empirical orthogonal functions work well if there are large differences in between-site magnitudes. If there are phase-lagged effects of interest, cross-correlation or empirical orthogonal function work well. For all other cases, each of these three metrics performed similarly. Therefore, these metrics may provide complimentary information if each are used to analyze the same dataset. Chapter II quantifies the filtering effects of temperature, egg bank composition, and disturbance on wetland invertebrate community dynamics and Chapter III quantifies the filtering effects of temperature, egg bank composition, and predation on wetland invertebrate community dynamics. Both chapters employ in-field mesocosm experiments in 100-gallon cattle tanks that were seeded with invertebrate propagules from either local ecosystems or from 5 different states. My results for these studies indicate that prairie pothole wetland communities are largely resistant to fluctuations in water levels though a few taxa (cladocerans, clam shrimp, fairy shrimp, damselfly larvae) saw decreased abundances in certain cases. Small changes in temperature (+1.1 °C) had little effect on the community except for intensifying the impact of the drawdown on clam shrimp and fairy shrimp. A greater change in temperature (+2.0 °C) led to more abundant clam shrimp and green algae, and larger-sized fairy shrimp, clam shrimp, and dytiscid larvae Predation by diving beetles led to decreased abundances of clam shrimp under warmer conditions or decreased abundances of copepods where alternative prey were scarce. In total, this work is a step toward improved understanding of the temporal dynamics of distant ecological communities. 

ABSTRACT Community assembly in aquatic habitats is heavily influenced by hydrology, but understanding the influence of other habitat conditions is also critical. Most studies focus on comparisons of geographically close communities that exist under diverse hydrological regimes, but this framework limits our ability to understand how conditions other than hydrology shape ephemeral wetland communities. Here, we investigated how macroinvertebrate communities vary with local, landscape, and climate variables in ephemeral wetlands across a large geographic range with few geographic barriers.We sampled ephemeral wetlands in North Dakota, New Mexico, and Texas (USA) in 2021 and in North Dakota and New Mexico in 2022. We used an array of hydrographic, climate, landscape, and spatial variables to relate taxonomic and functional macroinvertebrate community composition and diversity to habitat conditions.Taxonomic composition was overwhelmingly different among states and between years: landscape‐scale refuge availability explained variation in taxonomic composition, but local and climate‐scale variables only explained variation within the context of other variables. Trait composition was similar between most sampling groups, but distinct trait assemblages occurred in the North Dakota 2021 communities. No predictor variable matrix explained trait composition alone, but local, climate, landscape, and spatial arrangement predicted composition when considering the overlapping influence of other variables. Taxa and trait diversity indices were associated with increased refuge habitat at landscape scale.Our results show consistent trait structure across a large geographical scale in hydrologically similar wetlands, despite almost complete taxonomic turnover between regions. Patterns in taxonomic and functional composition imply that incorporating predictor variables at multiple scales is critical in understanding ephemeral wetland community composition.Despite similar hydrological regimes and potential for connectivity via dispersal, taxa replacement is high in ephemeral wetlands across regions within a single grassland macrosystem. Taxonomic composition and overall diversity change with the context provided by a diverse suite of structuring variables. Further, we show that in most cases, ephemeral hydrology elicits a similar trait response across climate regions.