Correlative species distribution modeling (SDM) is an important tool to predict distributions of invasive species. A unique challenge of implementing SDMs in aridland stream networks is identifying which streams are perennial and which of those offer suitable habitat for obligate aquatic species. Here, we map perennial streams and habitat suitability of invasive virile crayfish (Faxonius virilis) in the Lower Colorado River Basin (LCRB) in the southwestern USA, and quantify drivers of uncertainty in these projections.
View Article and Find Full Text PDFRising water temperature under climate change is affecting the physiology, population dynamics and geographic distribution of freshwater taxa. We propose a novel application of individual-based bioenergetics modelling (BEM) to assess the physiological impacts of warming on freshwater fishes across broad spatial extents. We test this approach using the Guadalupe bass (), a species of conservation and recreational significance that is endemic to central TX, USA.
View Article and Find Full Text PDFClimate change vulnerability depends on whether organisms can disperse rapidly enough to keep pace with shifting temperatures and find suitable habitat along the way. Here, we develop a method to examine where and for which species shifting isotherms will outpace species dispersal using stream networks of the southern Appalachian Mountains (United States) and their highly speciose and endemic fish fauna as a model system. By exploring alternative tributary and mainstem dispersal pathways, we identify tributaries as slow-climate-velocity pathways along which some fish can successfully disperse and thus keep pace with climate change.
View Article and Find Full Text PDFDescribing the physical habitat diversity of stream types is important for understanding stream ecosystem complexity, but also prioritizing management of stream ecosystems, especially those that are rare. We developed a stream classification system of six physical habitat layers (size, gradient, hydrology, temperature, valley confinement, and substrate) for approximately 1 million stream reaches within the Eastern United States in order to conduct an inventory of different types of streams and examine stream diversity. Additionally, we compare stream diversity to patterns of anthropogenic disturbances to evaluate associations between stream types and human disturbances, but also to prioritize rare stream types that may lack natural representation in the landscape.
View Article and Find Full Text PDFCities are concentrations of sociopolitical power and prime architects of land transformation, while also serving as consumption hubs of "hard" water and energy infrastructures. These infrastructures extend well outside metropolitan boundaries and impact distal river ecosystems. We used a comprehensive model to quantify the roles of anthropogenic stressors on hydrologic alteration and biodiversity in US streams and isolate the impacts stemming from hard infrastructure developments in cities.
View Article and Find Full Text PDFPrimary biodiversity data constitute observations of particular species at given points in time and space. Open-access electronic databases provide unprecedented access to these data, but their usefulness in characterizing species distributions and patterns in biodiversity depend on how complete species inventories are at a given survey location and how uniformly distributed survey locations are along dimensions of time, space, and environment. Our aim was to compare completeness and coverage among three open-access databases representing ten taxonomic groups (amphibians, birds, freshwater bivalves, crayfish, freshwater fish, fungi, insects, mammals, plants, and reptiles) in the contiguous United States.
View Article and Find Full Text PDFThe global recognition of the importance of natural flow regimes to sustain the ecological integrity of river systems has led to increased societal pressure on the hydropower industry to change plant operations to improve downstream aquatic ecosystems. However, a complete reinstatement of natural flow regimes is often unrealistic when balancing water needs for ecosystems, energy production, and other human uses. Thus, stakeholders must identify a prioritized subset of flow prescriptions that meet ecological objectives in light of realistic constraints.
View Article and Find Full Text PDFTrade-offs among functional traits produce multi-trait strategies that shape species' interactions with the environment and drive the assembly of local communities from regional species pools. Stream fish communities vary along stream size gradients and among hierarchically structured habitat patches, but little is known about how the dispersion of strategies varies along environmental gradients and across spatial scales. We used null models to quantify the dispersion of reproductive life history, feeding, and locomotion strategies in communities sampled at three spatial scales in a prairie stream network in Kansas, USA.
View Article and Find Full Text PDFResource managers increasingly rely on predictive models to understand species-environment relationships. Stream fish communities are influenced by longitudinal position within the stream network as well as local environmental characteristics that are constrained by catchment characteristics. Despite an abundance of studies quantifying species-environment relationships, few studies have evaluated the generality of these relationships among basins and spatial extents.
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