Riparian Shading and Groundwater Enhance Growth Potential for Smallmouth Bass in Ozark Streams

Moderation of stream temperatures by riparian shading and groundwater are known to promote growth and survival of salmonid fishes, but effects of riparian shade and groundwater on to be growth of warmwater stream fishes are poorly understood or assumed to be negligible. We used stream temperature models to relate shading from riparian vegetation and groundwater inflow to summer water temperatures in Missouri Ozark streams and evaluated effects of summer water temperatures on smallmouth bass, Micropterus dolomieu, growth using a bioenergetics model. Bioenergetics model simulations revealed that adult smallmouth bass in non-spring-fed streams have lower growth potential during summer than fish in spring-fed streams, are subject to mass loss when stream temperatures exceed 27°C, and will likely exhibit greater interannual variation in growth during summer if all growth-influencing factors, other than temperature, are identical between the two stream types. Temperature models indicated that increased riparian shading will expand the longitudinal extent of thermal habitat capable of supporting adult smallmouth bass growth in spring-fed stream reaches when mean daily air temperatures exceed 27°C. Optimum growth temperature (22°C) will be present only in spring-fed streams under these conditions. Potential for increasing shade through riparian restoration is greatest for streams \u3c5 m wide and along north–south reaches of larger streams. However, temperature models also indicated that restoring riparian shading to maximum levels throughout a watershed would increase the total stream mileage capable of supporting positive growth of adult smallmouth bass by only 1–6% when air temperatures are at or near average summer maxima; increases in suitable thermal habitat would be greatest in watersheds with higher spring densities. Riparian management for maintenance or restoration of the thermal habitat of adult smallmouth bass during summer should be focused in areas strongly influenced by groundwater. Restoring riparian shading along spring-fed warmwater streams will likely benefit adult smallmouth bass growth and may ultimately influence population sizes

The Great Lakes Hydrography Dataset: Consistent, Binational Watersheds for the Laurentian Great Lakes Basin

Ecosystem‐based management of the Laurentian Great Lakes, which spans both the United States and Canada, is hampered by the lack of consistent binational watersheds for the entire Basin. Using comparable data sources and consistent methods, we developed spatially equivalent watershed boundaries for the binational extent of the Basin to create the Great Lakes Hydrography Dataset (GLHD). The GLHD consists of 5,589 watersheds for the entire Basin, covering a total area of approximately 547,967 km2, or about twice the 247,003 km2 surface water area of the Great Lakes. The GLHD improves upon existing watershed efforts by delineating watersheds for the entire Basin using consistent methods; enhancing the precision of watershed delineation using recently developed flow direction grids that have been hydrologically enforced and vetted by provincial and federal water resource agencies; and increasing the accuracy of watershed boundaries by enforcing embayments, delineating watersheds on islands, and delineating watersheds for all tributaries draining to connecting channels. In addition, the GLHD is packaged in a publically available geodatabase that includes synthetic stream networks, reach catchments, watershed boundaries, a broad set of attribute data for each tributary, and metadata documenting methodology. The GLHD provides a common set of watersheds and associated hydrography data for the Basin that will enhance binational efforts to protect and restore the Great Lakes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134077/1/jawr12435_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134077/2/jawr12435.pd

Improving Predicted Distribution Models for Riverine Species: An Example from Nebraska

Modeling species distributions is in most instances, we believe, better if perceived as an exercise in modeling spatial patterns in habitat conditions. This perspective forces the modeler to think about factors and processes that influence local habitat and also to account for as many of these factors as possible in the modeling process. Local habitat conditions in riverine ecosystems (for example, pH, temperature, turbidity, permanence of flow, depths, velocities, substrate, cover, primary production, etc.) are influenced by a wide array of factors and processes operating at multiple spatial and temporal scales (Matthews 1998; Fausch et al. 2002). However, of primary importance is the interplay of watershed and local conditions (Hynes 1975; Richards et al. 1996; Rabeni and Sowa 2002). For instance, local substrate conditions are influenced by water and sediment delivery which are largely determined by watershed conditions and also local geomorphic conditions (for example, channel gradient) that affect sediment transport (Jacobson and Pugh 1999). Until recently it has been essentially impossible to quantify watershed conditions for thousands of streams segments across large geographic areas (for example, entire states). For this and other reasons, species distribution models developed for the Missouri Aquatic GAP Project were based on only a handful of local habitat variables (Sowa et al. 2007). This pilot project illustrated the importance and utility of these local variables for modeling the distribution of riverine biota, however, the resulting models had relatively low accuracy. We recently completed a project, involving development of statewide predicted distributions for fishes of Nebraska, in which we were able to quantify both watershed and local conditions for essentially all stream segments in the state and use them in the modeling process. Results from this project, which is the focus of this article, provide a specific example of how using both watershed and local variables for modeling the distribution of riverine biota can significantly improve model accuracy

Natural landscape and stream segment attributes influencing the distribution and relative abundance of riverine smallmouth bass in

Abstract.-Protecting and restoring fish populations on a regional basis are most effective if the multiscale factors responsible for the relative quality of a fishery are known. We spatially linked Missouri's statewide historical fish collections to environmental features in a geographic information system, which was used as a basis for modeling the importance of landscape and stream segment features in supporting a population of smallmouth bass Micropterus dolomieu. Decision tree analyses were used to develop probability-based models to predict statewide occurrence and within-range relative abundances. We were able to identify the range of smallmouth bass throughout Missouri and the probability of occurrence within that range by using a few broad landscape variables: the percentage of coarse-textured soils in the watershed, watershed relief, and the percentage of soils with low permeability in the watershed. The within-range relative abundance model included both landscape and stream segment variables. As with the statewide probability of occurrence model, soil permeability was particularly significant. The predicted relative abundance of smallmouth bass in stream segments containing low percentages of permeable soils was further influenced by channel gradient, stream size, spring-flow volume, and local slope. Assessment of model accuracy with an independent data set showed good concordance. A conceptual framework involving naturally occurring factors that affect smallmouth bass potential is presented as a comparative model for assessing transferability to other geographic areas and for studying potential land use and biotic effects. We also identify the benefits, caveats, and data requirements necessary to improve predictions and promote ecological understanding. The condition of many Missouri streams is perceived by many anglers and biologists to be deteriorating, resulting in the widespread decline of sport fish populations, especially smallmouth bass Micropterus dolomieu (Pflieger 1997). At present, fisheries managers have few tools to help monitor status and trends in smallmouth bass populations throughout their range or to predict population changes resulting from habitat degradation or habitat restoration. Smallmouth bass are a valuable recreational asset as well as a potential ecological indicator of natural stream conditions. Existing sampling data for smallmouth bass cover a small fraction (,1%) of the total stream kilometers in which this species is likely to occur. Resource managers need spatially comprehensive information to prioritize conservation efforts beyond sampled locations. Considering that over 175,000 km of stream exist within Missouri, the only realistic way to generate such information is through predictive modeling in a geographic information systems (GIS) setting. Identifying habitat potential at multiple spatial scales would provide a basis for habitat management important for the persistence of sport fish populations. The importance of scale to fish-habitat relations is well recognized; however, the large-scale processes that account for many habitat conditions remain poorly understood or addresse

Appendix B. A map showing the Ecological Drainage Units (EDUs) of Missouri.

A map showing the Ecological Drainage Units (EDUs) of Missouri

Appendix F. A map of stream segments flowing through public land categorized by GAP management status.

A map of stream segments flowing through public land categorized by GAP management status

Appendix D. A map example showing nine distinct Valley Segment Types (VSTs) that occur within a single 12-digit hydrologic unit.

A map example showing nine distinct Valley Segment Types (VSTs) that occur within a single 12-digit hydrologic unit

Appendix E. Maps of predicted total species richness (fish, mussels, and crayfish) and predicted richness of globally rare, threatened, and endangered species for Missouri.

Maps of predicted total species richness (fish, mussels, and crayfish) and predicted richness of globally rare, threatened, and endangered species for Missouri

Appendix M. Statewide management-status statistics for each fish, mussel, and crayfish species in Missouri, by stream length.

Statewide management-status statistics for each fish, mussel, and crayfish species in Missouri, by stream length

Appendix I. A table providing conservation status statistics for 74 distinct Valley Segment Types (VSTs) in Missouri.

A table providing conservation status statistics for 74 distinct Valley Segment Types (VSTs) in Missouri