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File An Economic Analysis of Improved Road‐Stream Crossings
Road‐stream crossings, which include culverts and bridges, are an essential element of our transportation networks, allowing roads to pass over rivers and streams. Our communities and our economies depend on functioning road networks and safe crossings. We also depend on healthy rivers and streams for clean water, recreation, and a host of other benefits, and we are learning more about the relationships between road‐stream crossing designs and their effect on natural areas. Undersized or poorly designed crossings fragment streams and disrupt the natural movement of water, sediment and aquatic organisms, causing erosion and degraded habitat. The most problematic of these crossings prevent aquatic organisms, such as brook trout, from accessing the upstream habitat they need to survive and reproduce. Yet crossings can be designed to avoid these problems. Improved road‐stream crossings deliver social, economic and ecological benefits and are a key element of adapting our infrastructure to a changing climate. Unfortunately, their initial cost can be a significant obstacle for highway departments with limited budgets.
Located in Science and Data / Brook Trout Related Publications
File Linking movement and reproductive history of brook trout to assess habitat connectivity in a heterogeneous stream network
1. Defining functional connectivity between habitats in spatially heterogeneous landscapes is a particular challenge for small-bodied aquatic species. Traditional approaches (e.g. mark–recapture studies) preclude an assessment of animal movement over the life cycle (birth to reproduction), and movement of individuals may not represent the degree of gene movement for fecund species. 2. We investigated the degree of habitat connectivity (defined as the exchange of individuals and genes between mainstem and tributary habitats) in a stream brook trout (Salvelinus fontinalis) population using mark–recapture [passive integrated transponder (PIT) tags], stationary PIT-tag antennae and genetic pedigree data collected over 4 years (3425 marked individuals). We hypothesised that: (i) a combination of these data would reveal higher estimates of animal movement over the life cycle (within a generation), relative to more temporally confined approaches, and (ii) movement estimates of individuals within a generation would differ from between-generation movement of genes because of spatial variation in reproductive success associated with high fecundity of this species. 3. Over half of PIT-tagged fish (juveniles and adults) were recaptured within 20 m during periodic sampling, indicating restricted movement. However, continuous monitoring with stationary PIT-tag antennae revealed distinct peaks in trout movements in June and October–November, and sibship data inferred post-emergence movements of young-of-year trout that were too small to be tagged physically. A combination of these methods showed that a moderate portion of individuals (28–33%) moved between mainstem and tributary habitats over their life cycle. 4. Patterns of reproductive success varied spatially and temporally. The importance of tributaries as spawning habitat was discovered by accounting for reproductive history. When individuals born in the mainstem reproduced successfully, over 50% of their surviving offspring were inferred to have been born in tributaries. This high rate of gene movement to tributaries was cryptic, and it would have been missed by estimates based only on movement of individuals. 5. This study highlighted the importance of characterising animal movement over the life cycle for inferring habitat connectivity accurately. Such movements of individuals can contribute to substantial gene movements in a fecund species characterised by high variation in reproductive success.
Located in Science and Data / Brook Trout Related Publications
File Impacts of Exotic Rainbow Trout on Habitat Use by Native Juvenile Salmonid Species at an Early Invasive Stage
The detrimental impact of introduced Rainbow Trout Oncorhynchus mykiss on native communities has been well documented around the world. Previous studies have focused on streams where the invasion has been successful and the species is fully established. In eastern Quebec, the invasion of Rainbow Trout is an ongoing process and, for now, there are few established populations. The presence of two native salmonids in these rivers, Atlantic Salmon Salmo salar and Brook Trout Salvelinus fontinalis, implies a risk of competition for habitat, despite the relatively low density of the Rainbow Trout populations, as all three species are known to use similar resources. In order to evaluate the strength of the interaction between the invading fish and the native species, we sampled nine rivers (five with Rainbow Trout and four free of Rainbow Trout) and characterized the habitat used by the three salmonids at the juvenile stage. River-scale analysis revealed that in invaded rivers, Rainbow Trout were associated with habitats characterized by closer proximity to the shoreline and by increasing shoreline cover. Estimates of habitat niche overlap integrating depth, water velocity, and substrate size revealed that niche overlap between Brook Trout and Atlantic Salmon significantly increased in the presence of Rainbow Trout. Furthermore, the two indigenous species preferred full cover in the absence of Rainbow Trout but in the presence of Rainbow Trout, which also preferred full cover, the indigenous species moved to more open habitats. Rainbow Trout showed a high growth rate, despite a size disadvantage at the beginning of the growing season, as compared with Atlantic Salmon and Brook Trout. It thus appears that even at an early stage of invasion, when its density is still low, Rainbow Trout significantly impact native salmonids.
Located in Science and Data / Brook Trout Related Publications
File application/x-troff-ms What predicts the use by brook trout (Salvelinus fontinalis) of terrestrial invertebrate subsidies in headwater streams?
1. Spatial subsidies are important resources for organisms in receiving habitats, particularly when production in those habitats is low. Terrestrial invertebrates provide a critical subsidy for trout, including eastern brook trout (Salvelinus fontinalis), but we have limited understanding of what causes input and use of these subsidies to vary among streams. 2. We predicted that forest successional stage would be an especially important driver of variation in terrestrial invertebrate subsidies to brook trout in headwater streams due to differences in terrestrial invertebrate biomass in early and late successional habitats. Specifically, we expected biomass of aerial invertebrates, those capable of dispersal to the stream, to be greater in early successional habitat than late successional habitat due to the nutrient-rich, herbaceous vegetation typical of early successional habitat. 3. We measured aerial terrestrial invertebrate biomass in early and late successional habitats, input to streams and use by resident brook trout in 12 first- and second-order catchments in northern New Hampshire, U.S.A. The study catchments represented a range of early successional habitat coverage (0–51.5%). We also measured a suite of reach-scale variables that might influence terrestrial invertebrate input and use by brook trout, including riparian forest conditions and benthic invertebrate biomass. 4. Within study catchments, aerial terrestrial invertebrate biomass and abundance were significantly higher in early successional habitats than late successional habitats. However, terrestrial invertebrate input to streams and use by brook trout were unrelated to per cent early successional habitat in the catchment, and to other catchment and riparian forest characteristics. These results indicate that the management for upland early successional habitat has little effect on terrestrial invertebrate subsidies to headwater streams and fish. 5. Surprisingly, benthic invertebrate biomass was the one significant predictor of per cent terrestrial invertebrates in brook trout diets. Use of terrestrial invertebrate subsidies declined with increasing benthic invertebrate biomass, suggesting that productivity in the aquatic environment influences the degree to which brook trout use terrestrial subsidies. Although subsidy inputs are controlled by the donor system, this study shows that use of these subsidies by consumers can be determined by conditions in the recipient habitat.
Located in Science and Data / Brook Trout Related Publications
File Broad-Scale Patterns of Brook Trout Responses to Introduced Brown Trout in New York
Brook Trout Salvelinus fontinalis and Brown Trout Salmo trutta are valuable sport fish that coexist in many parts of the world due to stocking introductions. Causes for the decline of Brook Trout within their native range are not clear but include competition with Brown Trout, habitat alteration, and repetitive stocking practices. New York State contains a large portion of the Brook Trout’s native range, where both species are maintained by stocking and other management actions.We used artificial neural network models, regression, principal components analysis, and simulation to evaluate the effects of Brown Trout, environmental conditions, and stocking on the distribution of Brook Trout in the center of their native range. We found evidence for the decline of Brook Trout in the presence of Brown Trout across many watersheds; 22% of sampled reaches where both species were expected to occur contained only Brown Trout. However, a model of the direct relationship between Brook Trout and Brown Trout abundance explained less than 1% of data variation. Ordination showed extensive overlap of Brook Trout and Brown Trout habitat conditions, with only small components of the hypervolume (multidimensional space) being distinctive. Subsequent analysis indicated higher abundances of Brook Trout in highly forested areas, while Brown Trout were more abundant in areas with relatively high proportions of agriculture. Simulation results indicated that direct interactions and habitat conditions were relatively minor factors compared with the effects of repeated stocking of Brown Trout into Brook Trout habitat. Intensive annual stocking of Brown Trout could eliminate resident Brook Trout in less than a decade. Ecological differences, harvest behavior, and other habitat changes can exacerbate Brook Trout losses. Custom stocking scenarios with Brown Trout introductions at relatively low proportions of resident Brook Trout populations may be able to sustain healthy populations of both species within their present range.
Located in Science and Data / Brook Trout Related Publications
File The Importance of Scale: Assessing and Predicting Brook Trout Status in its Southern Native Range
Occupancy models are of increasing interest to managers and natural resource decision makers. Assessment of status and trends, as well as the specific drivers influencing occupancy, both may change as a function of scale, and analyses conducted at multiple scales can help identify important mechanisms leading to changes in distributions. We analyzed extensive fine-scale occupancy data across the southern historic range of the brook trout, Salvelinus fontinalis to determine which landscape metrics and thresholds were useful in predicting brook trout presence across three relevant spatial scales and how brook trout occupancy varied by scale. Percentage occupancy declined markedly with increased spatial resolution, as 52% of watersheds (HUC10) but only 32% of subwatersheds (HUC12) and 14% of catchments (HUC14) were occupied. Across all three scales, habitats which were exclusively occupied by native brook trout (without non-native trout) were rare (<10%). CART models using GIS-derived landscape predictor variables were developed for three classification cases: Case 1:(brook trout; no brook trout), Case 2 (brook trout; non-native trout only; no trout), and Case 3 (brook trout only; brook and non-native trout; non-native trout only and no trout). Model results were sensitive to both scale and the number of classification categories with respect to classification accuracy, variable selection and variable threshold values. Classification accuracy tended to be lowest at the finest (catchment) scale potentially reflecting stochastic population processes and barriers to movement. Classification rates for the overall models were: Case 1: Watershed (80.19%); Subwatershed (85.06%); Catchment (71.13%); Case 2: Watershed (69.31%); Subwatershed (68.72%); Catchment (57.38%); Case 3: Watershed (58.91%); Subwatershed (59.83%); Catchment (47.59%). Our multiscale approach revealed soil permeability (positive) and atmospheric pollution (negative) to be important predictors. The predicted occupancy and observed status of brook trout appear to be influenced by the scale the data are collected and reported.
Located in Science and Data / Brook Trout Related Publications
File Chesapeake Bay Fish Passage Prioritization
An assessment of dams in the Chesapeake Bay watershed.
Located in Science and Data / Brook Trout Related Publications / Chesapeake Bay Brook Trout Management Strategy-References
File Patch Metrics: A Cost Effective Method for Monitoring Brook Trout Populations - Hudy et al. 2013
This paper describes a cost effective method for monitoring short and long term trends of Chesapeake Bay's Brook Trout populations.
Located in Science and Data / Brook Trout Related Publications / Chesapeake Bay Brook Trout Management Strategy-References
Project North Peninsula State Park Saltmarsh Restoration
This project will create a healthy, productive saltmarsh habitat (9 acres, including complete restoration of 2 acres of historical marsh habitat filled with spoil as a result of dredge activities and enhancement of 7 acres of saltmarsh) in North Peninsula State Park, Volusia County, Florida.
Located in Funded Projects / SARP Projects W2B
Restoration of Natural Hydrology and Habitat Complexity in the Machias, Rivers, Maine
This project will remove 11 remnant log drive dams and add large woody material to restore fish passage, stream connectivity and natural stream processes that will passively restore cold water habitat in the tributaries of the Machias River. A total of 27.2 miles of stream upstream of the dam sites will be affected by the project.
Located in Projects / 2006 - 2018 Projects / 2013 Projects
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