EBTJV

Population Response to Habitat Fragmentation in a Stream-Dwelling Brook Trout Population: Fragmentation can strongly influence population persistence and expression of life-history strategies in spatially-structured populations. In this study, we directly estimated size-specific dispersal, growth, and survival of stream-dwelling brook trout in a stream network with connected and naturally-isolated tributaries. We used multiple-generation, individual-based data to develop and parameterize a size-class and location-based population projection model, allowing us to test effects of fragmentation on population dynamics at local (i.e., subpopulation) and system-wide (i.e., metapopulation) scales, and to identify demographic rates which influence the persistence of isolated and fragmented populations. In the naturally-isolated tributary, persistence was associated with higher early juvenile survival (,45% greater), shorter generation time (one-half) and strong selection against large body size compared to the open system, resulting in a stage-distribution skewed towards younger, smaller fish. Simulating barriers to upstream migration into two currently-connected tributary populations caused rapid (2–6 generations) local extinction. These local extinctions in turn increased the likelihood of system-wide extinction, as tributaries could no longer function as population sources. Extinction could be prevented in the open system if sufficient immigrants from downstream areas were available, but the influx of individuals necessary to counteract fragmentation effects was high (7–46% of the total population annually). In the absence of sufficient immigration, a demographic change (higher early survival characteristic of the isolated tributary) was also sufficient to rescue the population from fragmentation, suggesting that the observed differences in size distributions between the naturally-isolated and open system may reflect an evolutionary response to isolation. Combined with strong genetic divergence between the isolated tributary and open system, these results suggest that local adaptation can ‘rescue’ isolated populations, particularly in one-dimensional stream networks where both natural and anthropogenically-mediated isolation is common. However, whether rescue will occur before extinction depends critically on the race between adaptation and reduced survival in response to fragmentation.
Located in Science and Data / Brook Trout Related Publications
EBTJV Roadmap to Restoration Fact Sheet (2007): EBTJV Roadmap to Restoration Fact Sheet
Located in Science and Data / EBTJV Reports / EBTJV Print Material
Climate Change 2007 Synthesis Report - IPCC: This report summarizes the findings of three Working Group reports and provides a synthesis that specifically addresses the issues of concern to policy makers in the domain of climate change.
Located in Science and Data / Brook Trout Related Publications / Chesapeake Bay Brook Trout Management Strategy-References
Restoration of Critical Habitat for LIsted Mussels and Fish, Big South Fork NRRA, TN/KY: The Big South Fork National River and Recreation Area is a focus for major conservation efforts due to the outstanding aquatic features found in the Big South Fork of the Cumberland River. The park is also a favorite location for equestrian riders, cyclists, and hikers. Managing a park for such multiple uses, while conserving biodiversity, is wrought with challenges.
Located in Funded Projects / SARP Projects W2B
Habitat Data Collection to aid Buck Creek Watershed Restoration: Restoration of native vegetation, streams, riparian zones and wetlands along Buck Creek and its tributaries is an ongoing project that needs physical habitat data specific to target species of fishes and mussels. The restoration effort is addressing Kentucky’s number one source of impairment — sedimentation and siltation. The overall goal is to tailor existing stream restoration efforts to benefit over 11 species of fish and mussels including sport fish, federally listed endangered species, and sensitive species in Buck Creek.
Located in Funded Projects / SARP Projects W2B
Oyster Reef Shoreline Restoration and Stabilization, MacDill AFB, FL: Over the past decade, the eastern shoreline of MacDill AFB has eroded, resulting in loss of native plant species such as black mangroves, palms, and 100-year-old live oaks. A five-phase project to stabilize the shoreline is creating a series of oyster reefs along undeveloped shoreline. The resultant oyster and mussel colonies will filter water and provide valuable habitat for fish and other aquatic resources. The reduced wave energy and accumulated sediment will encourage growth of native marsh grasses and mangroves, which will further stabilize the shoreline and improve the habitat.
Located in Funded Projects / SARP Projects W2B
Reintroduction of Native Brook Trout into Indian Flats Prong, Great Smoky Mountains National Park: Brook trout, the only salmonid native to the southeast, have lost about 75% of their historic range due to past logging activities and introduction of non-native trout. In 1993, the National Park Service identified 10 streams that can support native southern Appalachian brook trout (Salvelinus fontinalis). The long term goal is to restore historic range of habitat for this native species.
Located in Funded Projects / SARP Projects W2B
Habitat restoration for Southern Appalachian brook trout in 5 Cherokee National Forest, TN streams: Drought and stressed habitat conditions exacerbated natural competition for food and space between brook trout and rainbow trout in several creeks in the Cherokee National Forest. Both species, popular with anglers, were declining due to drought in recent years. By improving or restoring habitats, and removing rainbow trout from certain areas, both species can more easily thrive in the forest. (Photo: Cherokee National Forest Project Sites, TN)
Located in Funded Projects / SARP Projects W2B
Riparian habitat restoration for listed freshwater mussels in the Ochlockonee River Basin GA/FL: This project will restore riparian habitat for listed freshwater mussels in the Ochlockonee River Basin, within Georgia and Florida.
Located in Funded Projects / SARP Projects W2B
Whitethorn Creek Restoration, West Virginia: Whitethorn Creek, which is the most significant tributary in the Thorn Creek drainage of the South Branch of the Potomac, is historically recognized as supporting one of the best brook trout populations in West Virginia. This population has been significantly reduced in recent years as a result of land use impacts and two devastating flood events. The flood events altered instream habitat quality and washed away a large portion of riparian cover in the watershed. Following the loss of the relatively stable vegetated riparian corridor, livestock grazing has prevented re-growth and has caused widespread bank instability as a result of unregulated stream access. will result in the restoration and protection of approximately one mile of degraded brook trout habitat. This project will result in the reconnection of upstream spawning and rearing habitat to the mainstem of Thorn Creek. Reestablishment of the riparian corridor will provide lower overall water temperatures in addition to refuge areas during lower flows. The instream restoration will create habitat zones and a more stable hydrology through this reach and downstream.
Located in Projects / 2006 - 2018 Projects / 2007 Projects

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