"From biodiversity and aesthetic beauty to recreation and water for human use (e.g., municipal, industrial, agricultural), streams and rivers are socioeconomically and ecologically vital ecosystems. Coldwater streams and their biota are particularly unique, but they are increasingly threatened by climate change and associated temperature warming, changing hydrology (e.g., groundwater input, temperature; precipitation magnitude, intensity, frequency), and modifications to thermal and physical habitats that support aquatic organism growth, reproduction, and survival. As such, monitoring and modeling of stream thermal-hydrological regimes are important for sustainable management of coldwater fishes -- including Brook Trout (Salvelinus fontinalis), Brown Trout (Salmo trutta), and Rainbow Trout (Oncorhynchus mykiss ) -- in a changing climate. Ultimately, stream salmonid management decisions should foster social-ecological resilience -- the ability to retain robust stream ecosystems and human systems amid stressors such as climate change -- and promote resilience-based management. Using Michigan trout streams as a case study, the objectives of this dissertation were to: (1) Develop stream-specific temperature models to forecast stream thermal regimes and project thermal habitat suitability for Brook Trout, Brown Trout, and Rainbow Trout growth and survival throughout Michigan amid climate change; (2) Compare stream-specific and generalized (i.e., region-specific) temperature models relative to their accuracy (i.e., exactness of temperature prediction) and efficiency (i.e., applicability at management-relevant spatial extents) to develop a model implementation and evaluation approach that can be used for salmonid management programs in Michigan and beyond; (3) Integrate stream temperature modeling results with other thermal habitat information (e.g., groundwater input, watershed and riparian land use/land cover) and trout relative abundance to create a decision-support tool to assist fisheries professionals in operationalizing resilience-based salmonid management within and beyond Michigan in a changing climate; (4) Develop an approach for incorporating precipitation and groundwater into stream temperature modeling and thermal habitat management amid climate change. Climate change will affect Michigan stream trout in ways that vary among streams and populations. In most groundwater-dominated streams, thermal habitats can be accurately modeled and effectively managed using a generalized (i.e., region-specific) approach. However, stream-specific temperature modeling is considerably more accurate than a generalized approach in surface runoff-dominated systems, where the increased resource expenditure (e.g., money, time, personnel) associated with stream-specific modeling may be justified in systems containing high-priority fisheries resources (e.g. trophy individuals, endangered species). Decision-support tools are valuable for synthesizing biological, hydrological, and thermal data in ways that foster informed management decision-making on local and regional scales. Similarly, developing precipitation- and groundwater-corrected stream temperature models is important for accurate, efficient thermal habitat projections that promote resilience-based salmonid management in a changing climate."--Pages ii-iii.
Read
