USGS Science⌕ Search

SEARCH · USGS Science

Results for “Ecological Applications”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,639 records · Page 91Linked to original sources
USGS2018

Changes in long-term water quality of Baltimore streams are associated with both gray and green infrastructure

The steadily rising global urban population has placed substantial strain on urban water quality, and this strain is projected to increase for the foreseeable future. Considerable attention has been given to the hydrological and physico-chemical effects of urbanization on stream ecosystems. However, due to the relative infancy of the field of urban ecology, long-term water quality analyses in urban streams are sparse. Using a 15-year stream chemistry monitoring record from Baltimore, MD, USA, we quantified long-term trends in nitrate, phosphate, total nitrogen, total phosphorus, chloride, and sulfate export at several sites along a rural-urban gradient. We found no significant change in solute export at most sites, although we did find specific patterns of interest for certain solutes. For example, nitrogen export declined at the most headwater urban site, while phosphorus export declined at the most downstream urban site. Coupling long-term monitoring with data on gray and green infrastructure management throughout the landscape, we established relationships between solute export at the most downstream urban monitoring site and sanitary sewer overflows (SSOs), best management practice (BMP) implementation, and road salt application rates. Phosphorus export was correlated with BMP implementation in the watershed, whereas nitrogen export was related to SSOs. Despite highly urbanized watersheds, water quality does not appear to be declining at most of these sites, suggesting that current management may have limited further impairment. Results of our study suggest that both gray and green infrastructure are key for maintaining and improving water quality in this highly urbanized watershed.

Maryland↗
USGS2007

Restoration of waterbird habitats in Chesapeake Bay: Great expectations or Sisyphus revisited?

In the past half century, many waterbird populations in Chesapeake Bay have declined or shifted ranges, indicating major ecological changes have occurred. While many studies have focused on the problems associated with environmental degradation such as the losses of coastal wetlands and submerged vegetation, a number of restoration efforts have been launched in the past few decades to reverse the "sea of despair." Most pertinent to waterbirds, restoration of submerged aquatic vegetation (SAV) beds, tidal wetland restoration, oyster reef restoration, and island creation/restoration have benefited a number of species. State and federal agencies and non-government agencies have formed partnerships to spawn many projects ranging in size from less than 0.5 ha to ca. 1,000 ha. While most SAV, wetland, and oyster reef projects have struggled to different degrees over the past ten to twenty years with inconsistent methods, irregular monitoring, and unknown reasons for failures, recent improvements in techniques and application of adaptive management have been made. The large dredge-material island projects at Hart-Miller Island near Baltimore, Poplar Island west of Tilghman Island, Maryland, and Craney Island in Portsmouth, Virginia have provided large outdoor "laboratories" for wildlife, fishery, and wetland habitat creation. All three have proven to be important for nesting waterbirds and migrant shorebirds and waterfowl; however nesting populations at all three islands have been compromised to different degrees by predators. Restoration success for waterbirds and other natural resources depends on: (1) establishing realistic, quantifiable objectives and performance criteria, (2) continued monitoring and management (e.g., predator control), (3) targeted research to determine causality, and (4) careful evaluation under an adaptive management regime.

Waterbirds↗
USGS1993

Quantitative analysis of Ostracoda and water masses around Japan: Application to Pliocene and Pleistocene paleoceanography

An ostracode data base consisting of 273 samples from coretops and comprising 226 species was developed for the seas around the Japanese Islands to determine zoogeographic patterns and for application to Pliocene and Pleistocene paleoceanography in the area. Quantitative analyses of the 59 most common taxa between 0 and 300m water depth indicate that ostracode associations are controlled by the main oceanic water masses around Japan and that bottom water temperature is a key factor influencing species distributions. Ostracodes from the following water masses were studied: warm Kuroshio Current, Tsushima Current (Tsugaru Current and Soya Current), Japan Sea intermediate water, Japan Sea proper water and cold Oyashio Current. In order to apply the modem coretop data base to fossil ostracode assemblages, the modem analog technique (MAT) using a squared chord distance (SCD) measure of dissimilarity was tested as a means of comparing fossil and modem assemblages. SCD values of 0.25 or less adequately identify modem analogs from the coretop data set at the local ecological level (i.e. within the same modern bay), while values of 0.25-0.5 identify modem analogs at the level of the zoogeographic province. The MAT method was tested against 3 Pliocene and 11 Pleistocene formations in Japan to examine the use of the MAT in paleoceanographic reconstruction.

Micropaleontology↗
USGS2021

Stopover ecology of red knots in southwestern James Bay during southbound migration

Many shorebirds rely on small numbers of staging sites during long annual migrations. Numerous shorebird species are declining and understanding the importance of these staging sites is important for successful conservation. We surveyed endangered rufa red knots ( Calidris canutus rufa ) staging in James Bay, Ontario, Canada, during southbound migration in 2017 and 2018. We used mark‐resight data and count data in an integrated Bayesian analysis to quantify migration phenology, estimate passage population size, and model the age structure of the stopover population. Many adult red knots arrived in James Bay in a single wave in early August in 2017, whereas adult red knots arrived in multiple smaller waves in July and mid‐August in 2018. These waves may correspond with breeding phenology where more red knots bred successfully and arrived in one large event in 2017 and the higher number of earlier arrivals in July 2018 may have been failed breeders. We included a binomial generalized linear model in the integrated analysis to estimate that 20% and 10% of staging red knots were juveniles in 2017 and 2018, respectively. In future applications, this method could provide a metric to assess breeding performance and develop our understanding of its role in population declines. Overall, we estimated that up to 23% of the estimated rufa red knot population staged in southwestern James Bay for an average of 10–12 days. The region is a key staging site for endangered red knots and could be included in conservation planning.

James Bay↗
USGS1990

A method for testing whether model predictions fall within a prescribed factor of true values, with an application to pesticide leaching

A quantitative method is described for testing whether model predictions fall within a specified factor of true values. The technique is based on classical theory for confidence regions on unknown population parameters and can be related to hypothesis testing in both univariate and multivariate situations. A capability index is defined that can be used as a measure of predictive capability of a model, and its properties are discussed. The testing approach and the capability index should facilitate model validation efforts and permit comparisons among competing models. An example is given for a pesticide leaching model that predicts chemical concentrations in the soil profile.

Ecological Modelling↗
USGS2018

Overview of the oxygen isotope systematics of land snails from North America

Continental paleoclimate proxies with near-global coverage are rare. Land snail δ 18 O is one of the few proxies abundant in Quaternary sediments ranging from the tropics to the high Arctic tundra. However, its application in paleoclimatology remains difficult, attributable in part to limitations in published calibration studies. Here we present shell δ 18 O of modern small (<10 mm) snails across North America, from Florida (30°N) to Manitoba (58°N), to examine the main climatic controls on shell δ 18 O at a coarse scale. This transect is augmented by published δ 18 O values, which expand our coverage from Jamaica (18°N) to Alaska (64°N). Results indicate that shell δ 18 O primarily tracks the average annual precipitation δ 18 O. Shell δ 18 O increases 0.5–0.7‰ for every 1‰ increase in precipitation δ 18 O, and 0.3–0.7‰ for every 1°C increase in temperature. These relationships hold true when all taxa are included regardless of body size (ranging from ~1.6 to ~58 mm), ecology (herbivores, omnivores, and carnivores), or behavior (variable seasonal active periods and mobility habits). Future isotopic investigations should include calibration studies in tropical and high-latitude settings, arid environments, and along altitudinal gradients to test if the near linear relationship between shell and meteoric precipitation δ 18 O observed on a continental scale remains significant.

Quaternary Research↗
USGS1997

Review of selected features of the natural system model, and suggestions for applications in south Florida

A study was conducted to review selected features of the Natural System Model, version 4.3. The Natural System Model is a regional-scale model that uses recent climatic data and estimates of historic vegetation and topography to simulate pre-canal-drainage hydrologic response in south Florida. Equations used to represent the hydrologic system and the numerical solution of these equations in the model were documented and reviewed. Convergence testing was performed using 1965 input data, and selected other aspects of the model were evaluated. Some conclusions from the evaluation of the Natural System Model include the following observations. Simulations were generally insensitive to the temporal resolution used in the model. However, reduction of the computational cell size from 2-mile by 2-mile to 2/3-mile by 2/3-mile resulted in a decrease in spatial mean ponding depths for October of 0.35 foot for a 3-hour time step. Review of the computer code indicated that there is no limit on the amount of water that can be transferred from the river system to the overland flow system, on the amount of seepage from the river to the ground-water system, on evaporation from the river system, or on evapotranspiration from the overland-flow system. Oscillations of 0.2 foot or less in simulated river stage were identified and attributed to a volume limiting function which is applied in solution of the overland-flow equations. The computation of the resistance coefficient is not consistent with the computation of overland-flow velocity. Ground-water boundary conditions do not always ensure a no-flow condition at the boundary. These inconsistencies had varying degrees of effects on model simulations, and it is likely that simulations longer than 1 year are needed to fully identify effects. However, inconsistencies in model formulations should not be ignored, even if the effects of such errors on model results appear to be small or have not been clearly defined. The Natural System Model can be a very useful tool for estimating pre-drainage hydrologic response in south Florida. The model includes all of the important physical processes needed to simulate a water balance. With a few exceptions, these hydrologic processes are represented in a reasonable manner using empirical, semiempirical, and mechanistic relations. The data sets that have been assembled to represent physical features, and hydrologic and meteorological conditions are quite extensive in their scope. Some suggestions for model application were made. Simulation results from the Natural System Model need to be interpreted on a regional basis, rather than cell by cell. The available evidence suggests that simulated water levels should be interpreted with about a plus or minus 1 foot uncertainty. It is probably not appropriate to use the Natural System Model to estimate pre-drainage discharges (as opposed to hydroperiods and water levels) at a particular location or across a set of adjacent computational cells. All simulated results for computational cells within about 10 miles of the model boundaries have a higher degree of uncertainty than results for the interior of the model domain. It is most appropriate to interpret the Natural System Model simulation results in connection with other available information. Stronger linkages between hydrologic inputs to the Everglades and the ecological response of the system would enhance restoration efforts.

Florida↗
USGS2012

A framework for understanding semi-permeable barrier effects on migratory ungulates

1. Impermeable barriers to migration can greatly constrain the set of possible routes and ranges used by migrating animals. For ungulates, however, many forms of development are semi-permeable, and making informed management decisions about their potential impacts to the persistence of migration routes is difficult because our knowledge of how semi-permeable barriers affect migratory behaviour and function is limited. 2. Here, we propose a general framework to advance the understanding of barrier effects on ungulate migration by emphasizing the need to (i) quantify potential barriers in terms that allow behavioural thresholds to be considered, (ii) identify and measure behavioural responses to semi-permeable barriers and (iii) consider the functional attributes of the migratory landscape (e.g. stopovers) and how the benefits of migration might be reduced by behavioural changes. 3. We used global position system (GPS) data collected from two subpopulations of mule deer Odocoileus hemionus to evaluate how different levels of gas development influenced migratory behaviour, including movement rates and stopover use at the individual level, and intensity of use and width of migration route at the population level. We then characterized the functional landscape of migration routes as either stopover habitat or movement corridors and examined how the observed behavioural changes affected the functionality of the migration route in terms of stopover use. 4. We found migratory behaviour to vary with development intensity. Our results suggest that mule deer can migrate through moderate levels of development without any noticeable effects on migratory behaviour. However, in areas with more intensive development, animals often detoured from established routes, increased their rate of movement and reduced stopover use, while the overall use and width of migration routes decreased. 5. Synthesis and applications . In contrast to impermeable barriers that impede animal movement, semi-permeable barriers allow animals to maintain connectivity between their seasonal ranges. Our results identify the mechanisms (e.g. detouring, increased movement rates, reduced stopover use) by which semi-permeable barriers affect the functionality of ungulate migration routes and emphasize that the management of semi-permeable barriers may play a key role in the conservation of migratory ungulate populations.

Journal of Applied Ecology↗
USGS2025

Accounting for non-random samples with distance sampling to estimate population density

A critical assumption of standard distance sampling is that sampling lines are located such that animals are uniformly distributed as a function of distance from the line. Failure to meet this assumption can introduce bias in the estimator. Many studies have used landscape features, such as roads or rivers, as lines, which can violate assumptions of distance sampling in two ways. First, animals may be attracted or repelled by the landscape feature due to human activity (e.g. along roads) or habitat characteristics associated with the feature (e.g. rivers). Second, sampling along landscape features may not be representative of the larger area of interest. We used auxiliary data to generalize the distance sampling estimator and relax assumptions of a uniform distribution of animals relative to distance from the line (i.e. density gradient) and to allow the distribution of animals to differ by habitat type. The generalized estimator provides unbiased estimates of density within the area sampled but may not be representative of the study area. To address the problem of landscape features providing unrepresentative sampling, we used a resource selection model to estimate the proportion of the population that occurred within the surveyed area to obtain an estimate of abundance for the desired area of inference. We demonstrate our modified distance sampling estimator using white-tailed deer ( Odocoileus virginianus ) in a 972-km 2 study area. We conducted infrared surveys of deer from roads to collect distance-to-transect data. We used locations of radio-collared deer to model the distribution of deer relative to the transects and to develop a resource selection model of deer based on distance to roads, habitat type, elevation and slope to account for roads being a non-representative sample of the study area. Synthesis and applications . When using landscape features as survey lines, the density gradient and deer distribution can introduce either positive or negative bias, which makes it impossible to assess the bias introduced without auxiliary data. The estimator we developed can improve precision because we obtained a better fit to distance observations and accounts for non-random placement of transects with minimal loss of precision.

Journal of Applied Ecology↗
USGS2003

Soil seed banks and the potential restoration of forested wetlands after farming

1 Changes in farming practice provide an opportunity to restore once extensive forested wetlands on agricultural land. In some parts of the world, however, it has proved difficult to restore the full complement of plant species through natural regeneration. Similarly, the restoration of forested wetlands by replanting has often resulted in ecosystems of low diversity. Better methods of restoring these important ecosystems are now required and baldcypress swamps provide an opportunity to investigate alternative approaches to the restoration of forested wetlands. This study examined the composition of seed banks of farmed fields to determine their value in restoring swamps in the south-eastern United States. 2 A seed bank assay of soils from baldcypress swamps was conducted to determine the extent to which seeds are maintained during farming for various lengths of time. Soils from swamps that were farmed for 0–50 years were collected near the northern boundary of the Mississippi Alluvial Valley along the Cache River, Illinois. Soils were placed in a glasshouse setting in flooded and freely drained conditions, and the numbers and species of seeds germinating were recorded. 3 Woody species including trees, shrubs, and vines were poorly represented in seed banks of both farmed and intact sites (51 and 9 sites, respectively). Missing dominants in the seed banks included tree species with short-lived seeds such as Taxodium distichum and Nyssa aquatica . Cephalanthus occidentalis constituted the most abundantly dispersed seed of all woody species. 4 Herbaceous species were well represented in the seed banks of both farmed and intact swamps (species richness of 207 vs. 173 species, respectively) suggesting that herbaceous species may live longer than woody species in seed banks. Few of the herbaceous species decreased in seed density in seed banks with time under cultivation, although seed density was lower at sites that had not been farmed. Species that relied on vegetative organs for dispersal were absent in the seed banks of farmed sites including Heteranthera dubia , Hottonia inflata , Lemna minor , Lemna trisulca and Wolffia columbiana . These species may require active reintroduction during restoration. 5 Synthesis and applications. Both restoration ecologists and managers of nature conservation areas need to be cognisant of seed bank and dispersal characteristics of species to effectively restore and manage forested wetlands. In the case of baldcypress swamps, critical components of the vegetation are not maintained in seed banks, which may make these floodplain wetlands difficult to restore via natural recolonization. Ultimately, the successful restoration of abandoned farm fields to forested wetlands may depend on the re-engineering of flood pulsing across landscapes to reconnect dispersal pathways.

Illinois↗
USGS2024

A meta-analysis highlights the idiosyncratic nature of tradeoffs in laboratory models of virus evolution

Different theoretical frameworks have been invoked to guide the study of virus evolution. Three of the more prominent ones are (i) the evolution of virulence, (ii) life history theory, and (iii) the generalism–specialism dichotomy. All involve purported tradeoffs between traits that define the evolvability and constraint of virus-associated phenotypes. However, as popular as these frameworks are, there is a surprising paucity of direct laboratory tests of the frameworks that support their utility as broadly applicable theoretical pillars that can guide our understanding of disease evolution. In this study, we conduct a meta-analysis of direct experimental evidence for these three frameworks across several widely studied virus–host systems: plant viruses, fungal viruses, animal viruses, and bacteriophages. We extracted 60 datasets from 28 studies and found a range of relationships between traits in different analysis categories (e.g., frameworks, virus–host systems). Our work demonstrates that direct evidence for relationships between traits is highly idiosyncratic and specific to the host–virus system and theoretical framework. Consequently, scientists researching viral pathogens from different taxonomic groups might reconsider their allegiance to these canons as the basis for expectation, explanation, or prediction. Future efforts could benefit from consistent definitions, and from developing frameworks that are compatible with the evidence and apply to particular biological and ecological contexts.

Virus Evolution↗
USGS2012

Mapping outdoor recreationists' perceived social values for ecosystem services at Hinchinbrook Island National Park, Australia

Coastal ecosystems are increasingly faced with human impacts. To better understand these changing conditions, biophysical and economic values of nature have been used to prioritize spatial planning efforts and ecosystem-based management of human activities. Less is known, however, about how to characterize and represent non-material values in decision-making. We collected on-site and mailback survey data ( n = 209), and analyzed these data using the Social Values for Ecosystem Services (SolVES) GIS application to incorporate measures of social value and natural resource conditions on Hinchinbrook Island National Park, Australia. Our objectives in this paper are to: 1) determine the spatial distribution and point density of social values for ecosystem services; 2) examine the relationship between social values and natural resource conditions; and 3) compare social value allocations between two subgroups of outdoor recreationists. Results suggest that high priority areas exist on Hinchinbrook's land and seascapes according to the multiple values assigned to places by outdoor recreationists engaged in consumptive (e.g., fishing) and non-consumptive (e.g., hiking) activities. We examine statistically significant spatial clustering across two subgroups of the survey population for three value types that reflect Recreation, Biological Diversity, and Aesthetic qualities. The relationship between the relative importance of social values for ecosystem services and spatially-defined ecological data is explored to guide management decision-making in the context of an island national park setting.

Hinchinbrook Island National Park↗
USGS2020

Parsing the effects of demography, climate, and management on recurrent brucellosis outbreaks in elk

1. Zoonotic pathogens can harm human health and well-being directly or by impacting livestock. Pathogens that spillover from wildlife can also impair conservation efforts if humans perceive wildlife as pests. Brucellosis, caused by the bacterium Brucella abortus, circulates in elk and bison herds of the Greater Yellowstone Ecosystem and poses a risk to cattle and humans. Our goal was to understand the relative effects of climatic drivers, host demography, and management control programs on disease dynamics. 2. Using >20 years of serologic, demographic, and environmental data on brucellosis in elk, we built stochastic compartmental models to assess the influences of climate forcing, herd immunity, population turnover, and management interventions on pathogen transmission. Data were collected at feedgrounds visited in winter by free-ranging elk in Wyoming, USA. 3. Snowpack, hypothesized as a driver of elk aggregation and thus brucellosis transmission, was strongly correlated across feedgrounds. We expected this variable to drive synchronized disease dynamics across herds. Instead, we demonstrate asynchronous epizootics driven by variation in demographic rates. 4. We evaluated the effectiveness of test-and-slaughter of seropositive female elk at two feedgrounds. Test-and-slaughter temporarily reduced herd-level seroprevalence but likely reduced herd immunity while removing few infectious individuals, resulting in subsequent outbreaks once the intervention ceased. We simulated an alternative strategy of removing seronegative female elk and found it would increase herd immunity, yielding fewer infections. We evaluated a second experimental treatment wherein feeding density was reduced at one feedground, but we found no evidence for an effect despite a decade of implementation. 5. Synthesis and applications: Positive serostatus is often weakly correlated with infectiousness but is nevertheless used to make management decisions including lethal removal in wildlife disease systems. We show how this can have adverse consequences whereas efforts that maintain herd immunity can have longer-term protective effects. Climatic drivers may not result in synchronous disease dynamics across populations unless vital rates are also similar because demographic factors have a large influence on disease patterns.

Idaho, Montana, Wyoming↗
USGS2007

Linking resources with demography to understand resource limitation for bears

1. Identifying the resources that limit growth of animal populations is essential for effective conservation; however, resource limitation is difficult to quantify. Recent advances in geographical information systems (GIS) and resource modelling can be combined with demographic modelling to yield insights into resource limitation. 2. Using long-term data on a population of black bears Ursus americanus, we evaluated competing hypotheses about whether availability of hard mast (acorns and nuts) or soft mast (fleshy fruits) limited bears in the southern Appalachians, USA, during 1981-2002. The effects of clearcutting on habitat quality were also evaluated. Annual survival, recruitment and population growth rate were estimated using capture-recapture data from 101 females. The availability of hard mast, soft mast and clearcuts was estimated with a GIS, as each changed through time as a result of harvest and succession, and then availabilities were incorporated as covariates for each demographic parameter. 3. The model with the additive availability of hard mast and soft mast across the landscape predicted survival and population growth rate. Availability of young clearcuts predicted recruitment, but not population growth or survival. 4. Availability of hard mast stands across the landscape and availability of soft mast across the landscape were more important than hard mast production and availability of soft mast in young clearcuts, respectively. 5. Synthesis and applications. Our results indicate that older stands, which support high levels of hard mast and moderate levels of soft mast, should be maintained to sustain population growth of bears in the southern Appalachians. Simultaneously, the acreage of intermediate aged stands (10-25 years), which support very low levels of both hard mast and soft mast, should be minimized. The approach used in this study has broad application for wildlife management and conservation. State and federal wildlife agencies often possess long-term data on both resource availability and capture-recapture for wild populations. Combined, these two data types can be used to estimate survival, recruitment, population growth, elasticities of vital rates and the effects of resource availability on demographic parameters. Hence data that are traditionally used to understand population trends can be used to evaluate how and why demography changes over time. ?? 2007 The Authors.

Journal of Applied Ecology↗
USGS2019

Microsite enhancements for soil stabilization and rapid biocrust colonization in degraded drylands

In dryland ecosystems, natural recovery of biological soil crusts (biocrusts) following disturbance may be slow or inhibited, necessitating active restoration practices. While biocrusts can be readily propagated under environmentally controlled conditions, rehabilitation in the field is complicated by environmental stresses which may be particularly acute in degraded, destabilized soils with harsh climatic conditions at the soil surface. In this study, we first present the results of a field trial at a severely degraded rangeland site examining the stabilizing effects of various soil amendments (polysaccharide glues and polyacrylamides) in combination with biocrust inoculum. We found that a psyllium compound was the only amendment to maintain effectiveness after 19 months, and the only treatment that maintained biocrust inoculum throughout the trial. In a subsequent short‐term experiment where plots were shaded and watered, we examined how biocrust inoculation rate (0, 20, and 40% initial cover) and the psyllium‐based amendment affected biocrust growth. After 4 months, visible biocrust cover in inoculated plots was greater than in controls, but only chlorophyll a exhibited a dosage‐response to inoculum application rate, indicating preferential establishment of cyanobacteria. Psyllium did not affect biocrust development but did improve soil stability. Shade and watering buffered against temperature extremes (up to 15°C) and increased the duration of moist surface conditions necessary for biocrust growth by up to 30%, mimicking conditions more common in the fall and winter months. Our results suggest that inducing early successional biocrusts on a highly degraded site is possible with suitable microclimate conditions.

Restoration Ecology↗
USGS2006

Hierarchical models of animal abundance and occurrence

Much of animal ecology is devoted to studies of abundance and occurrence of species, based on surveys of spatially referenced sample units. These surveys frequently yield sparse counts that are contaminated by imperfect detection, making direct inference about abundance or occurrence based on observational data infeasible. This article describes a flexible hierarchical modeling framework for estimation and inference about animal abundance and occurrence from survey data that are subject to imperfect detection. Within this framework, we specify models of abundance and detectability of animals at the level of the local populations defined by the sample units. Information at the level of the local population is aggregated by specifying models that describe variation in abundance and detection among sites. We describe likelihood-based and Bayesian methods for estimation and inference under the resulting hierarchical model. We provide two examples of the application of hierarchical models to animal survey data, the first based on removal counts of stream fish and the second based on avian quadrat counts. For both examples, we provide a Bayesian analysis of the models using the software WinBUGS.

Journal of Agricultural, Biological, and Environme↗
USGS2015

Diel resource partitioning among juvenile Atlantic Salmon, Brown Trout, and Rainbow Trout during summer

Interspecific partitioning of food and habitat resources has been widely studied in stream salmonids. Most studies have examined resource partitioning between two native species or between a native species and one that has been introduced. In this study we examine the diel feeding ecology and habitat use of three species of juvenile salmonids (i.e., Atlantic Salmon Salmo salar , Brown Trout Salmo trutta , and Rainbow Trout Oncorhynchus mykiss ) in a tributary of Skaneateles Lake, New York. Subyearling Brown Trout and Rainbow Trout fed more heavily from the drift than the benthos, whereas subyearling Atlantic Salmon fed more from the benthos than either species of trout. Feeding activity of Atlantic Salmon and Rainbow Trout was similar, with both species increasing feeding at dusk, whereas Brown Trout had no discernable feeding peak or trough. Habitat availability was important in determining site-specific habitat use by juvenile salmonids. Habitat selection was greater during the day than at night. The intrastream, diel, intraspecific, and interspecific variation we observed in salmonid habitat use in Grout Brook illustrates the difficulty of acquiring habitat use information for widespread management applications.

North American Journal of Fisheries Management↗
USGS2021

Effects of surveying for the federally endangered Spruce-fir Moss Spider (Microhexura montivaga Crosby & Bishop) on its bryophyte habitat

Microhexura montivaga (Spruce-fir Moss Spider) is a federally endangered arachnid endemic to high-elevation montane conifer forests of the southern Appalachian Mountains. The spider is cryptic and difficult to monitor because this species lives in the interface between the bryophyte mat and the rock surface. Since temporary removal of the bryophyte mat is necessary to monitor the spider, surveyors may negatively impact the spider's habitat during monitoring. To help inform survey protocol for this endangered species, we studied reattachment rates of bryophyte mats to rock surfaces after their removal. In 2017, we surveyed sixty 10 cm × 10 cm plots, assigning a plot to either control or treatment (i.e., application of water post-reattachment). We monitored plots for 1 year post-survey to determine reattachment rates. The majority of plots (70%) reestablished after 1 year, whereas 15% did not reattach or showed substantial prolonged (e.g., ∼1 year) desiccation and 15% completely fell off or had 100% prolonged desiccation and were chlorotic. We found that mat depth and overstory canopy cover had no effect on mat reestablishment, although bryophyte type did. We found no difference between treatment and control plots, suggesting that no treatment is needed for mats to reestablish under the conditions described. Rock slope significantly influenced reestablishment rates, highlighting that surveying bryophyte mats on slopes >80% may diminish or destroy habitat. Further research is needed to determine long-term monitoring effects on the spider and its habitat, especially in relation to disturbance regimes and ecological restoration of Picea rubens (Red Spruce).

Southeastern Naturalist↗