Perry, Stephen

Probabilistic measures of climate change vulnerability, adaptation action benefits, and related uncertainty from maximum temperature metric selection: Predictions of the projected changes in species distribution models and potential adaptation action benefits can help guide conservation actions. There is substantial uncertainty in projecting species distributions into an unknown future, however, which can undermine confidence in predictions or misdirect conservation actions if not properly considered. Recent studies have shown that the selection of alternative climate metrics describing very different climatic aspects (e.g., mean air temperature vs. mean precipitation) can be a substantial source of projection uncertainty. It is unclear, however, how much projection uncertainty might stem from selecting among highly correlated, ecologically similar climate metrics (e.g., maximum temperature in July, maximum 30-day temperature) describing the same climatic aspect (e.g., maximum temperatures) that is known to limit a species’ distribution. It is also unclear how projection uncertainty might propagate into predictions of the potential benefits of adaptation actions that might lessen climate change effects. We provide probabilistic measures of climate change vulnerability, adaptation action benefits, and related uncertainty stemming from the selection of four maximum temperature metrics for brook trout (Salvelinus fontinalis), a cold-water salmonid of conservation concern in the eastern U.S. Projected losses in suitable stream length varied by as much as 20% among alternative maximum temperature metrics for mid-century climate projections, which was similar to variation among three climate models. Similarly, the regional average predicted increase in brook trout occurrence probability under an adaptation action scenario of full riparian forest restoration varied by as much as 0.2 among metrics. Our use of Bayesian inference provides probabilistic measures of vulnerability and adaptation action benefits for individual stream reaches that properly address statistical uncertainty and can help guide conservation actions. Our study demonstrates that even relatively small differences in the definitions of climate metrics can result in very different projections and reveal high uncertainty in predicted climate change effects.
Located in Science and Data / Brook Trout Related Publications
Stream Assessment and Monitoring: Research publications related to assessing and monitoring streams.
Located in Science and Data / Brook Trout Related Publications
A Function-Based Framework for Stream Assessment & Restoration Projects: Stream restoration efforts have increased significantly in the US over the past few decades and are now recognized as a billion-dollar industry. These restoration efforts stem from centuries of abuse as humans continue to alter the riverine landscape for a variety of purposes, including farming, logging, mining and development on the floodplain, and the subsequent need for channelization and flood control. These activities have significantly diminished the natural functions of our stream corridors. Today stream corridor restoration efforts seek to improve or restore these lost functions. A variety of federal, state and local programs, along with efforts from non-profit organizations, provide funding for these programs. The goals are varied and range from simple streambank stabilization projects to watershed scale restoration. For these projects to be successful it is important to know why the project is being completed and what techniques are best suited to restore the lost functions. Knowing why a project is needed requires some form of functional assessment followed by clear project goals. To successfully restore stream functions, it is necessary to understand how these different functions work together and which restoration techniques influence a given function. It is also imperative to understand that stream functions are interrelated and build on each other in a specific order, a functional hierarchy. If this hierarchy is understood, it is easier to establish project goals. And with clearer goals, it is easier to evaluate project success.
Located in Science and Data / Brook Trout Related Publications / Stream Assessment and Monitoring
Sampling strategies for estimating brook trout effective population size: The influence of sampling strategy on estimates of effective population size (Ne) from single-sample genetic methods has not been rigorously examined, though these methods are increasingly used. For headwater salmonids, spatially close kin association among age-0 individuals suggests that sampling strategy (number of individuals and location from which they are collected) will influence estimates of Ne through family representation effects. We collected age-0 brook trout by completely sampling three headwater habitat patches, and used microsatellite data and empirically parameterized simulations to test the effects of different combinations of sample size (S = 25, 50, 75, 100, 150, or 200) and number of equally-spaced sample starting locations (SL = 1, 2, 3, 4, or random) on estimates of mean family size and effective number of breeders (Nb). Both S and SL had a strong influence on estimates of mean family size and ^ Nb; however the strength of the effects varied among habitat patches that varied in family spatial distributions. The sampling strategy that resulted in an optimal balance between precise estimates of Nb and sampling effort regardless of family structure occurred with S = 75 and SL = 3. This strategy limited bias by ensuring samples contained individuals from a high proportion of available families while providing a large enough sample size for precise estimates. Because this sampling effort performed well for populations that vary in family structure, it should provide a generally applicable approach for genetic monitoring of iteroparous headwater stream fishes that have overlapping generations.
Located in Science and Data / Brook Trout Related Publications / Stream Assessment and Monitoring
Brook Trout Genetics Research: Research studies related to Brook Trout genetics.
Located in Science and Data / Brook Trout Related Publications
Fragmentation and Patch Size Shape Genetic Structure of Brook Trout Populations: We tested the relative influence of habitat patch size and connectivity on genetic structure and effective population size in eight brook trout (Salvelinus fontinalis) habitat patches in a watershed in Virginia, USA. Variation at eight microsatellite loci in 2229 young-of-the-year brook trout for two successive cohorts (2010 and 2011) was examined. Genetic differentiation across all populations was pronounced. Overall F'ST was 0.397 (95% CI: 0.322–0.525) and overall FST was 0.124 (95% CI: 0.096–0.159). Above-barrier patch size had a strong positive relationship with genetic diversity, Nˆ b, and genetic differentiation. Our analysis is consistent with greater extinction risk in smaller above-barrier patches. Larger above-barrier patches contained greater genetic diversity but reduced Nˆ b relative to adjacent below-barrier patches. The primary effect of barriers may be to reduce available above-barrier spawning habitat, even for larger above-barrier patches. Below-barrier patches also showed evidence of reduced genetic diversity and lack of connectivity. Genetic monitoring focused at gaining a broader understanding of the relationships here will be necessary to fully evaluate local extinction risks.
Located in Science and Data / Brook Trout Related Publications / Brook Trout Genetics Research
Chesapeake Bay Brook Trout Management Strategy-References: This folder contains the publications cited in the Chesapeake Bay Brook Trout Management Strategy (2015-2025).
Located in Science and Data / Brook Trout Related Publications
Assessment and predictive model for Brook Trout in the eastern US - Thieling 2006: This Masters Thesis describes models used to predict the classification of Brook Trout status at the subwatershed scale.
Located in Science and Data / Brook Trout Related Publications / Chesapeake Bay Brook Trout Management Strategy-References
Distribution and Status of Brook Trout in eastern U.S. - Hudy et al. 2008: This publication describes the distribution and status of Brook Trout across its historic eastern U. S. range.
Located in Science and Data / Brook Trout Related Publications / Chesapeake Bay Brook Trout Management Strategy-References
The Importance of Scale: Assessing and Predicting Brook Trout Status - Hudy et al. 2013: This article analyzes extensive fine-scale occupancy data across the southern historic range of Brook Trout.
Located in Science and Data / Brook Trout Related Publications / Chesapeake Bay Brook Trout Management Strategy-References

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