Peterson D.P.,U.S. Fish and Wildlife Service |
Wenger S.J.,Trout Unlimited |
Rieman B.E.,Rocky Research |
Isaak D.J.,Rocky Research
Fisheries | Year: 2013
Fisheries professionals are increasingly tasked with incorporating climate change projections into their decisions. Here we demonstrate how a structured decision framework, coupled with analytical tools and spatial data sets, can help integrate climate and biological information to evaluate management alternatives. We present examples that link downscaled climate change scenarios to fish populations for two common types of problems: (1) strategic spatial prioritization of limited conservation resources and (2) deciding whether removing migration barriers would benefit a native fish also threatened with invasion by a nonnative competitor. We used Bayesian networks (BNs) to translate each decision problem into a quantitative tool and implemented these models under historical and future climate projections. The spatial prioritization BN predicted a substantial loss of habitat for the target species by the 2080s and provided a means to map habitats and populations most likely to persist under future climate projections. The barrier BN applied to three streams predicted that barrier removal decisions-previously made assuming a stationary climate-were likely robust under the climate scenario considered. The examples demonstrate the benefit of structuring the decision-making process to clarify management objectives, formalize assumptions, synthesize current understanding about climate effects on fish populations, and identify key uncertainties requiring further investigation.
Splinter D.K.,University of Wisconsin - Whitewater |
Dauwalter D.C.,Trout Unlimited
Geomorphology | Year: 2016
Regional climate, geology, vegetation, and land use influence hydrogeomorphic processes, which influence stream channel form and the recruitment and transport of wood in streams. We studied relationships between channel morphology and frequencies of large in-channel wood in three upland ecoregions of eastern Oklahoma where streams contain high fish diversity and valuable sport fisheries. We surveyed 138 streams for wood within the Boston Mountains (n = 30), Ozark Highlands (n = 30), and Ouachita Mountain (n = 78) ecoregions. Our study investigated whether (1) the frequency of large wood differed among ecoregions; (2) channel morphology influenced the distribution of large wood within and among ecoregions; and (3) a relationship existed between the frequency and size of trees in the riparian zone and the frequency of large wood within and among ecoregions. The frequency of single large wood pieces did not differ among ecoregions or vary with drainage area. However, the presence of one or more wood accumulation (2 to 4 pieces) increased with drainage area and increased at a higher rate in the Boston Mountains and Ozark Highlands than in the Ouachita Mountains. The frequency of single wood pieces decreased in narrower channels with larger substrates but increased in larger stream channels overall. No association existed between riparian tree density and in-channel wood in study reaches. We discuss these results in the context of wood recruitment and transport, and highlight key questions that remain regarding wood in eastern Oklahoma streams. © 2016
Budy P.,Utah State University |
Baker M.,University of Maryland Baltimore County |
Dahle S.K.,Trout Unlimited
Environmental Management | Year: 2011
Anthropogenic impairment of water bodies represents a global environmental concern, yet few attempts have successfully linked fish performance to thermal habitat suitability and fewer have distinguished co-varying water quality constraints. We interfaced fish bioenergetics, field measurements, and Thermal Remote Imaging to generate a spatially-explicit, high-resolution surface of fish growth potential, and next employed a structured hypothesis to detect relationships among measures of fish performance and co-varying water quality constraints. Our thermal surface of fish performance captured the amount and spatial-temporal arrangement of thermally-suitable habitat for three focal species in an extremely heterogeneous reservoir, but interpretation of this pattern was initially confounded by seasonal covariation of water residence time and water quality. Subsequent path analysis revealed that in terms of seasonal patterns in growth potential, catfish and walleye responded to temperature, positively and negatively, respectively; crappie and walleye responded to eutrophy (negatively). At the high eutrophy levels observed in this system, some desired fishes appear to suffer from excessive cultural eutrophication within the context of elevated temperatures whereas others appear to be largely unaffected or even enhanced. Our overall findings do not lead to the conclusion that this system is degraded by pollution; however, they do highlight the need to use a sensitive focal species in the process of determining allowable nutrient loading and as integrators of habitat suitability across multiple spatial and temporal scales. We provide an integrated approach useful for quantifying fish growth potential and identifying water quality constraints on fish performance at spatial scales appropriate for whole-system management. © 2011 Springer Science+Business Media, LLC (outside the USA).
Carah J.K.,The Nature Conservancy |
Blencowe C.C.,Blencowe Watershed Management |
Wright D.W.,Campbell Timberland Management |
Bolton L.A.,Trout Unlimited
North American Journal of Fisheries Management | Year: 2014
Like many rivers and streams in forests of the Pacific Northwest, California north coast rivers and streams have been depleted of downed wood through timber harvest and direct wood removal. Due to the important role of wood in creating and maintaining salmonid habitat, wood augmentation has become a common element of stream restoration. Restoration efforts in North America often focus on building anchored, engineered wood structures at the site scale; however, these projects can fail to meet restoration goals at the watershed scale, do not closely mimic natural wood loading processes or dynamics, and can be expensive to implement. For critically imperiled populations of Coho Salmon Oncorhynchus kisutch in California, there is a strong impetus to achieve as much habitat restoration as possible in priority watersheds in the shortest time and with limited resources, so cost-efficient techniques are necessary. In this multi-site project, we investigated unanchored techniques for wood loading to evaluate cost and contribution to salmonid habitat in Mendocino County, California. Over a period of 6 years, 72.4 km of stream were treated with 1,973 pieces of strategically placed wood. We found that unanchored wood loading techniques were much less costly than commonly used anchored techniques, reliably improved habitat, and retained wood at high rates (mean = 92%) in small- to moderate-sized streams, at least over the short term (<6 years). The average cost of design and construction for the unanchored projects was US$259 per log, equivalent to 22% of the cost associated with the anchored wood augmentation methods examined here. Our results suggest that this unanchored wood loading approach has the potential to increase the pace and scale at which wood augmentation projects are implemented in the Pacific Northwest and beyond.Received January 22, 2014; accepted June 25, 2014. © 2014, © American Fisheries Society 2014.
Wenger S.J.,Trout Unlimited |
Olden J.D.,University of Washington
Methods in Ecology and Evolution | Year: 2012
1.Ecologists have long sought to distinguish relationships that are general from those that are idiosyncratic to a narrow range of conditions. Conventional methods of model validation and selection assess in- or out-of-sample prediction accuracy but do not assess model generality or transferability, which can lead to overestimates of performance when predicting in other locations, time periods or data sets. 2.We propose an intuitive method for evaluating transferability based on techniques currently in use in the area of species distribution modelling. The method involves cross-validation in which data are assigned non-randomly to groups that are spatially, temporally or otherwise distinct, thus using heterogeneity in the data set as a surrogate for heterogeneity among data sets. 3.We illustrate the method by applying it to distribution modelling of brook trout (Salvelinus fontinalis Mitchill) and brown trout (Salmo trutta Linnaeus) in western United States. We show that machine-learning techniques such as random forests and artificial neural networks can produce models with excellent in-sample performance but poor transferability, unless complexity is constrained. In our example, traditional linear models have greater transferability. 4.We recommend the use of a transferability assessment whenever there is interest in making inferences beyond the data set used for model fitting. Such an assessment can be used both for validation and for model selection and provides important information beyond what can be learned from conventional validation and selection techniques. © 2012 The Authors. Methods in Ecology and Evolution © 2012 British Ecological Society.