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At least 919 records · Page 51Linked to original sources
USGS2019

The Life of P: A biogeochemical and sociopolitical challenge in the Everglades

• Phosphorus (P) is an essential element for all life forms, yet to understand its life cycle and impact we need to grasp not only the biogeochemical life of P, but also how P intersects with human activities and values. • Phosphorus is the limiting nutrient in the oligotrophic Everglades ecosystem. Thus, the anthropogenic addition of P to the landscape and its subsequent transport, transformation, and persistence throughout the Everglades are critical to both the visual appearance and the ecological integrity of the Everglades ecosystem. • Legal and political attention to P in the Everglades have created a powerful social-cultural legacy. This legacy includes the continuing influence of P in Everglades restoration, the dissemination of knowledge about P cycling and mitigation among rural and urban Everglades residents, and social and political realignment of management priorities. • Management decisions based on legal mandates require not only robust scientific data about P-related processes, but also information on the behavior, well-being, and political decisions of tribal nations, agricultural enterprises, anglers, and others who use the South Florida landscape.

Florida↗
USGS2024

Hydrodynamic and salinity tesponse to tidal restoration in the Herring River Estuary, MA, considering present and future sea levels

Coastal salt marshes are crucial ecosystems that provide habitat for a variety of species, improve water quality, and play a major role in the global carbon cycle. However, many salt marshes have been severely damaged by human activities such as diking and draining for urban development. Recently, there has been a noticeable shift toward the prioritization of coastal marsh restoration to re-establish their ecosystem services. The removal of anthropogenic barriers such as dikes, sluices, and culverts is a critical component of many projects because it allows for the restoration of tidal flow to support natural hydrologic regimes and salinity conditions, which play a dominant role in determining the ecological and biogeochemical functioning of marshes. This study examines how proposed removal of hydraulic structures will influence the hydrologic potential for marsh restoration in the Herring River Estuary in Cape Cod, Massachusetts, USA. Construction of dikes, roadways, and low-capacity culverts over the last century has substantially restricted tidal flow in the Herring River Estuary, leading to degradation of salt marsh habitat. The estuary is now undergoing the first phase of a restoration project to re-introduce natural hydrologic conditions, increase salinity, and restore salt marsh habitat. To assess how the Herring River Estuary will respond to human- and climate-driven modifications, we develop and apply a validated hydrodynamic model to simulate the complex tidal and salinity dynamics of the estuary under a range of restoration and sea level rise scenarios. We then quantify how salinity and critical hydrologic variables, including tidal range and depth of mean high water, will evolve for various restoration scenarios considering present and future sea levels. The results of this research can inform coastal management and restoration plans that re-create the natural functioning of the system while protecting critical infrastructure and reducing the risk of restoration failure.

Massachusetts↗
USGS2004

Biodiversity of Fungi : Inventory and Monitoring Methods

Biodiversity of Fungi is essential for anyone collecting and/or monitoring any fungi. Fascinating and beautiful, fungi are vital components of nearly all ecosystems and impact human health and our economy in a myriad of ways. Standardized methods for documenting diversity and distribution have been lacking. An wealth of information, especially regrading sampling protocols, compiled by an international team of fungal biologists, make Biodiversity of Fungi an incredible and fundamental resource for the study of organismal biodiversity. Chapters cover everything from what is a fungus, to maintaining and organizing a permanent study collection with associated databases; from protocols for sampling slime molds to insect associated fungi; from fungi growing on and in animals and plants to mushrooms and truffles. The chapters are arranged both ecologically and by sampling method rather than by taxonomic group for ease of use. The information presented here is intended for everyone interested in fungi, anyone who needs tools to study them in nature including naturalists, land managers, ecologists, mycologists, and even citizen scientists and sophiscated amateurs. Fungi are among the most important organisms in the world; they play vital roles in ecosystem functions and have wide-ranging effects, both positive and negative, on humans and human-related activities. There are about 1.5 million species of fungi. The combination of fungal species and abundances in an ecosystem are often used as indicators of ecosystem health and as indicators of the effects of pollution and of different management and use plans. Because of their significance, it is important that these organisms be monitored. This book is the first comprehensive treatment of fungal inventory and monitoring, including standardized sampling protocols as well as information on study design, sample preservation, and data analysis.

Book↗
USGS2010

Conserving migratory land birds in the New World: Do we know enough?

Migratory bird needs must be met during four phases of the year: breeding season, fall migration, wintering, and spring migration; thus, management may be needed during all four phases. The bulk of research and management has focused on the breeding season, although several issues remain unsettled, including the spatial extent of habitat influences on fitness and the importance of habitat on the breeding grounds used after breeding. Although detailed investigations have shed light on the ecology and population dynamics of a few avian species, knowledge is sketchy for most species. Replication of comprehensive studies is needed for multiple species across a range of areas. Information deficiencies are even greater during the wintering season, when birds require sites that provide security and food resources needed for survival and developing nutrient reserves for spring migration and, possibly, reproduction. Research is needed on many species simply to identify geographic distributions, wintering sites, habitat use, and basic ecology. Studies are complicated, however, by the mobility of birds and by sexual segregation during winter. Stable-isotope methodology has offered an opportunity to identify linkages between breeding and wintering sites, which facilitates understanding the complete annual cycle of birds. The twice-annual migrations are the poorest-understood events in a bird's life. Migration has always been a risky undertaking, with such anthropogenic features as tall buildings, towers, and wind generators adding to the risk, Species such as woodland specialists migrating through eastern North America have numerous options for pausing during migration to replenish nutrients, but some species depend on limited stopover locations. Research needs for migration include identifying pathways and timetables of migration, quality and distribution of habitats, threats posed by towers and other tall structures, and any bottlenecks for migration. Issues such as human population growth, acid deposition, climate change, and exotic diseases are global concerns with uncertain consequences to migratory birds and even lesscertain remedies. Despite enormous gaps in our understanding of these birds, research, much of it occurring in the past 30 years, has provided sufficient information to make intelligent conservation efforts but needs to expand to handle future challenges. ?? 2010 by the Ecological Society of America.

Ecological Applications↗
USGS2023

Adult Sea Lamprey approach and passage at the Milford Dam fishway, Penobscot River, Maine, United States

Objective Sea Lamprey Petromyzon marinus provide important ecological services within their native range, such as nutrient cycling, and can also act as a prey source for other species. Adult Sea Lamprey must access freshwater rivers to spawn, and because of this they are susceptible to changes in river connectivity. Human-made structures, such as dams, can exclude them from usable habitat. Sea Lamprey dam passage has not been extensively studied in Maine, despite Maine being within the native range of this species. The goals of this study were to evaluate upstream passage efficiency at the Milford Dam on the Penobscot River, Maine, and to provide comprehensive information about adult Sea Lamprey passage at five other dams throughout the Penobscot River watershed. Methods In 2020–2021 we captured and tagged 150 Sea Lamprey at the Milford Dam, the lowest dam in the Penobscot River, Maine, and displaced them downstream to assess passage efficiency at this dam and five upstream dams. In 2020, 50 Sea Lamprey were released on the east shore of the river downstream of Milford Dam; in 2021, the east shore release was repeated with an additional 50 fish and another 50 fish were released on the west shore. Result Between 70–82% of Sea Lamprey were observed passing Milford Dam again after mean delay times of 9–11 days. The release location did not affect dam passage success or the amount of time that was required to locate and use the passage structures. Sea Lampreys from both release groups were equally likely to approach the entrance to the fishway upon returning to Milford Dam, despite the fishway being located against the eastern shore of the river. However, high flows shortly after release may have resulted in higher attraction to the fishway in 2020. Passage success at dams upstream of Milford was highly variable. All Sea Lamprey were able to successfully navigate past West Enfield Dam (100% passage, n = 63), whereas Brownsmill Dam apparently acted as a complete barrier to further migration (0% passage, n = 7). Fish from all years and release groups together had a median upstream migration distance of 38.8 km after fish had passed Milford Dam, and a maximum observed upstream travel distance of approximately 100 km, indicating that most tagged Sea Lamprey ended their migration in the vicinity of a dam. Conclusion The results of this study indicate that Sea Lamprey have high passage efficiency at the Milford Dam and highlight areas within the Penobscot River basin—such as the Brownsmill Dam—where passage facilities are currently inadequate for Sea Lamprey.

Maine↗
USGS2007

Tidal freshwater forested wetlands: Future research needs and an overview of restoration: Chapter 17

Studies of tidal freshwater forested wetlands are few in contrast to the diversity of conditions and information needs that exist for this ecosystem type. Basic information is lacking on the physiological ecology of major wetland tree species under natural settings, the structure and dynamics of pure and mixed species communities, soil-plant interactions, biogeochemistry, hydrology, soils, wildlife habitat, primary biotic and abiotic functions, and the response of these systems to natural and human-caused disruptions. Existing information is often not in a form that can be applied to ecosystem problems, especially those related to management, restoration, or creation of tidal swamps. Accordingly, there is a critical need for research on fundamental biotic and abiotic processes and functions in tidal forested wetland landscapes on a local and regional scale. In this chapter, we detail those research needs, and we highlight some restoration ideas for tidal freshwater forested wetlands with the hope that much additional research will follow.

Book chapter↗
USGS1983

Habitat Suitability Index Models: Alewife and blueback herring

Alewives and blueback herring are anadromous clupeids found along the Atlantic coast in marine, estuarine, and riverine habitats, depending upon life stage. Both are important commercial species, used fresh or salted for human consumption, and used as crab bait, fish meal (particularly in animal food manufacturing), and fish oil. Alewife and blueback herring are marketed collectively as 'river herring,' a term that will be used for both species in this report. River herring play important ecological roles. In marine, estuarine, and riverine food webs, they occupy a level between zooplankton, their principal food, and piscivores.

FWS/OBS↗
USGS2020

Estimating abiotic thresholds for sagebrush condition class in the western United States

Sagebrush ecosystems of the western United States can transition from extended periods of relatively stable conditions to rapid ecological change if acute disturbances occur. Areas dominated by native sagebrush can transition from species-rich native systems to altered states where non-native annual grasses dominate, if resistance to annual grasses is low. The non-native annual grasses provide relatively little value to wildlife, livestock, and humans and function as fuel that increases fire frequency. The more land area covered by annual grasses, the higher the potential for fire, thus reducing the potential for native vegetation to reestablish, even when applying restoration treatments. Mapping areas of stability and areas of change using machine-learning algorithms allows both the identification of dominant abiotic variables that drive ecosystem dynamics and the variables’ important thresholds. We develop a decision-tree model with rulesets that estimate three classes of sagebrush condition (i.e., sagebrush recovery, tipping point [ecosystem degradation], and stable). We find rulesets that primarily drive development of the sagebrush recovery class indicate areas of midelevations (1 602 m), warm 30-yr July temperature maximums (tmax) (30.62°C), and 30-yr March precipitation (ppt) averages equal to 26.26 mm, about 10% of the 30-yr annual ppt values. Tipping point and stable classes occur at elevations that are lower (1 505 m) and higher (1 939 m), respectively, more mesic during March and annually, and experience lower 30-yr July tmax averages. These defined variable averages can be used to understand current dynamics of sagebrush condition and to predict where future transitions may occur under novel conditions.

Arizona, California, Colorado, Idaho, Montana, Neb↗
USGS2021

Short-term responses to a human-altered landscape do not affect fat dynamics of a migratory ungulate

According to risk-sensitive foraging theory, animals should make foraging decisions that balance nutritional costs and gains to promote fitness. Human disturbance is a form of perceived risk that can prompt avoidance of risky habitat over acquisition of food. Consequently, behavioural responses to perceived risk could induce nutritional costs. Population declines often coincide with increases in human disturbance, which likely is associated with direct and indirect habitat loss. Nevertheless, behavioural and physiological responses to perceived risks associated with human disturbance could be an added nutritional deficit with population-level repercussions. Using GPS-collar data from three populations of migratory mule deer Odocoileus hemionus exposed to a gradient of established industrial energy development on winter ranges where direct and indirect habitat loss were well documented, we evaluated whether exposure and behavioural responses to human disturbance alter changes in nutritional condition (i.e. fat reserves) over winter. Although animals exhibited behaviours indicative of perceived risk of human disturbance, such as increased movement rates and avoidance of infrastructure, exposure and behavioural responses to human disturbance had little to no measurable effect on fat loss over a winter. Instead, catabolism of fat reserves occurred primarily as a function of the amount of fat animals had entering winter, suggesting that, in the short term, animals were able to mitigate the energetic costs of perceived risk of human disturbance over winter. Animals, however, did not appear to overcome persistent food limitations, and animals with less food availability lost more fat over winter. Our findings heed caution in using short-term behavioural and physiological responses to inform long-term nutritional consequences of human disturbance. Although animals appear to mitigate the energetic costs of perceived risk, food limitations exacerbated by broader-scale avoidance of food near human disturbance may be the primary pathway causing the frequently observed population declines following human disturbance to pristine landscapes.

Wyoming↗
USGS2011

Canine detection of free-ranging brown treesnakes on Guam

We investigated canine teams (dogs and their handlers) on Guam as a potential tool for finding invasive brown treesnakes (Boiga irregularis) in the wild. Canine teams searched a 40 × 40 m forested area for a snake that had consumed a dead mouse containing a radio-transmitter. To avoid tainting the target or target area with human scent, no snake was handled or closely approached prior to searches. Trials were conducted during the morning when these nocturnal snakes were usually hidden in refugia. A radiotracker knew the snake's location, but dog handlers and search navigators did not. Of 85 trials conducted over four months, the two canine teams had an average success rate of 35% of correctly defining an area ≤ 5 × 5 m that contained the transmittered snake; the team with more experience prior to the trials had a success rate of 44% compared with 26% for the less experienced team. Canine teams also found 11 shed skins from wild snakes. Although dogs alerted outside the vicinity of transmittered snakes, only one wild, non-transmittered snake was found during the trials, possibly reflecting the difficulty humans have in locating non-transmittered brown treesnakes in refugia. We evaluated success at finding snakes as a function of canine team, number of prior trials (i.e. experience gained during the trials), recent canine success at finding a target snake, various environmental conditions, snake perch height, and snake characteristics (snout-vent length and sex). Success rate increased over the course of the trials. Canine team success also increased with increasing average humidity and decreased with increasing average wind speed. Our results suggest dogs could be useful at detecting brown treesnakes in refugia, particularly when compared to daytime visual searches by humans, but techniques are needed to help humans find and extract snakes once a dog has alerted.

New Zealand Journal of Ecology↗
USGS2012

Predicting the likelihood of altered streamflows at ungauged rivers across the conterminous United States

An approach is presented in this study to aid water-resource managers in characterizing streamflow alteration at ungauged rivers. Such approaches can be used to take advantage of the substantial amounts of biological data collected at ungauged rivers to evaluate the potential ecological consequences of altered streamflows. National-scale random forest statistical models are developed to predict the likelihood that ungauged rivers have altered streamflows (relative to expected natural condition) for five hydrologic metrics (HMs) representing different aspects of the streamflow regime. The models use human disturbance variables, such as number of dams and road density, to predict the likelihood of streamflow alteration. For each HM, separate models are derived to predict the likelihood that the observed metric is greater than (‘inflated’) or less than (‘diminished’) natural conditions. The utility of these models is demonstrated by applying them to all river segments in the South Platte River in Colorado, USA, and for all 10-digit hydrologic units in the conterminous United States. In general, the models successfully predicted the likelihood of alteration to the five HMs at the national scale as well as in the South Platte River basin. However, the models predicting the likelihood of diminished HMs consistently outperformed models predicting inflated HMs, possibly because of fewer sites across the conterminous United States where HMs are inflated. The results of these analyses suggest that the primary predictors of altered streamflow regimes across the Nation are (i) the residence time of annual runoff held in storage in reservoirs, (ii) the degree of urbanization measured by road density and (iii) the extent of agricultural land cover in the river basin.

River Research and Applications↗
USGS1996

The role of mineral resource assessments in ecological stewardship

Bedrock geology and mineral resource assessments can provide important information for ecologically based stewardship of land and water. Combining information derived from mineral resource assessments and geoenvironmental mineral deposit models provides a means to rapidly screen a large region for potential for mineral concentrations, to assess the environmental risk associated with mineralized bedrock and with human disturbances of mineralized bedrock, and to establish priorities for further studies.

Open-File Report↗
USGS2017

Using high-throughput DNA sequencing, genetic fingerprinting, and quantitative PCR as tools for monitoring bloom-forming and toxigenic cyanobacteria in Upper Klamath Lake, Oregon, 2013 and 2014

Monitoring the community structure and metabolic activities of cyanobacterial blooms in Upper Klamath Lake, Oregon, is critical to lake management because these blooms degrade water quality and produce toxic microcystins that are harmful to humans, domestic animals, and wildlife. Genetic tools, such as DNA fingerprinting by terminal restriction fragment length polymorphism (T-RFLP) analysis, high-throughput DNA sequencing (HTS), and real-time, quantitative polymerase chain reaction (qPCR), provide more sensitive and rapid assessments of bloom ecology than traditional techniques. The objectives of this study were (1) to characterize the microbial community at one site in Upper Klamath Lake and determine changes in the cyanobacterial community through time using T-RFLP and HTS in comparison with traditional light microscopy; (2) to determine relative abundances and changes in abundance over time of toxigenic Microcystis using qPCR; and (3) to determine relative abundances and changes in abundance over time of Aphanizomenon , Microcystis , and total cyanobacteria using qPCR. T-RFLP analysis of total cyanobacteria showed a dominance of only one or two distinct genotypes in samples from 2013, but results of HTS in 2013 and 2014 showed more variations in the bloom cycle that fit with the previous understanding of bloom dynamics in Upper Klamath Lake and indicated that potentially toxigenic Microcystis was more prevalent in 2014 than in years prior. The qPCR-estimated copy numbers of all target genes were higher in 2014 than in 2013, when microcystin concentrations also were higher. Total Microcystis density was shown with qPCR to be a better predictor of late-season increases in microcystin concentrations than the relative proportions of potentially toxigenic cells. In addition, qPCR targeting Aphanizomenon at one site in Upper Klamath Lake indicated a moderate bloom of this species (corresponding to chlorophyll a concentrations between approximately 75 and 200 micrograms per liter) from mid-June to mid-August, 2014. After August 18, the Aphanizomenon bloom was overtaken by Microcystis late in the season as microcystin concentrations peaked. Overall, results of this study showed how DNA-based, genetic methods may provide rapid and sensitive diagnoses for the presence of toxigenic cyanobacteria and that they are useful for general monitoring or ecological studies and identification of cyanobacterial community members in complex aquatic habitats. These same methods can also be used to simultaneously address spatial (horizontal and vertical) and temporal variation and under different conditions. Additionally, with some modifications, the same techniques can be applied to different sample types, including water, sediment, and tissue.

Oregon↗
USGS1989

Chlamydial infections in free-living birds

Most studies of chlamydial infections in free-living wild birds have been limited to surveys for the presence of Chlamydia psittaci or antibody to C psittaci and have largely been done in association with the identification of chlamydiosis in human beings, commercial fowl, or pet birds. The emphasis of these studies has been to determine the prevalence of infection and the potential role of wild birds in the spread of chlamydiae to domestic birds and human beings. Little is known about the epizootiology of chlamydiosis in free-living birds or its affect on their population dynamics. The following article is a summary of reported studies of chlamydiosis in free-living wild birds in relation to host range, ecologic aspects of transmission and maintenance, and the prevalence of disease.

Journal of the American Veterinary Medical Associa↗
USGS2019

Public access for pheasant hunters: Understanding an emerging need

Ring-necked pheasant ( Phasianus colchicus ; i.e., pheasant) hunting participation is declining across North America, reflecting a larger downward trend in American hunting participation and threatening benefits to grassland conservation and rural economies. To stabilize and expand the pheasant hunting population, we must first identify factors that influence pheasant hunter participation. We used an extensive in-person hunter survey to test the hypothesis that hunter demographics interact with social-ecological traits of hunting locations to affect hunter decisions, outcomes, and perceptions. We built a series of Bayesian mixed effects models to parse variation in demographics, perceptions, and hunt outcomes of pheasant hunters interviewed at public access hunting sites across 3 regions in Nebraska, USA, that varied in pheasant abundance and proximity to urban population centers. Among pheasant hunters in Nebraska, access to private lands was negatively related to the human population density of a pheasant hunter's home ZIP code and the distance a hunter had traveled to reach a hunting location. Pheasant hunters interviewed closer to metropolitan areas tended to be more urban and travel shorter distances, and their parties were more likely to include youth but less likely to include dogs. Hunter satisfaction was positively associated with seeing and harvesting pheasants and hunting with youth. Whereas youth participation and the number of pheasants seen varied by study region, hunter satisfaction did not differ across regions, suggesting that hunters may calibrate their expectations and build their parties based on where they plan to hunt. The variation in hunter demographics across hunting locations and disconnects between social and ecological correlates of hunter satisfaction suggests that diverse pheasant hunting constituencies will be best served by diverse pheasant hunting opportunities.

Nebraska↗
USGS2021

Schistosome infection in Senegal is associated with different spatial extents of risk and ecological drivers for Schistosoma haematobium and S. mansoni

Schistosome parasites infect more than 200 million people annually, mostly in sub-Saharan Africa, where people may be co-infected with more than one species of the parasite. Infection risk for any single species is determined, in part, by the distribution of its obligate intermediate host snail. As the World Health Organization reprioritizes snail control to reduce the global burden of schistosomiasis, there is renewed importance in knowing when and where to target those efforts, which could vary by schistosome species. This study estimates factors associated with schistosomiasis risk in 16 villages located in the Senegal River Basin, a region hyperendemic for Schistosoma haematobium and S . mansoni . We first analyzed the spatial distributions of the two schistosomes’ intermediate host snails ( Bulinus spp. and Biomphalaria pfeifferi , respectively) at village water access sites. Then, we separately evaluated the relationships between human S . haematobium and S . mansoni infections and (i) the area of remotely-sensed snail habitat across spatial extents ranging from 1 to 120 m from shorelines, and (ii) water access site size and shape characteristics. We compared the influence of snail habitat across spatial extents because, while snail sampling is traditionally done near shorelines, we hypothesized that snails further from shore also contribute to infection risk. We found that, controlling for demographic variables, human risk for S . haematobium infection was positively correlated with snail habitat when snail habitat was measured over a much greater radius from shore (45 m to 120 m) than usual. S . haematobium risk was also associated with large, open water access sites. However, S . mansoni infection risk was associated with small, sheltered water access sites, and was not positively correlated with snail habitat at any spatial sampling radius. Our findings highlight the need to consider different ecological and environmental factors driving the transmission of each schistosome species in co-endemic landscapes.

PLoS Neglected Tropical Diseases↗
USGS1987

The relation between human presence and occurrence of Giardia Cysts in streams in the Sierra Nevada, California

A portable apparatus was used to filter large quantities of water from streams in California's Sierra Nevada. Samples were processed and examined for Giardia spp. Cysts of Giardia were detected in 22 of 49 (44.9 percent) samples collected at sites downstream from areas of high recreational use and in 5 of 29 (17.2 percent) samples collected at sites downstream from areas of low recreational use. These data indicate that intensity of human use may play a significant role or be a useful indicator in Giardia contamination of surface water.

California↗
USGS2007

Coccidioides niches and habitat parameters in the southwestern United States: A matter of scale

To determine habitat attributes and processes suitable for the growth of Coccidioides, soils were collected from sites in Arizona, California, and Utah where Coccidioides is known to have been present. Humans or animals or both have been infected by Coccidioides at all of the sites. Soil variables considered in the upper 20 cm of the soil profile included pH, electrical conductivity, salinity, selected anions, texture, mineralogy, vegetation types and density, and the overall geomorphologic and ecological settings. Thermometerswere buried to determine the temperature range in the upper part of the soil where Coccidioides is often found. With the exception of temperature regimes and soil textures, it is striking that none of the other variables or group of variables that might be definitive are indicative of the presence of Coccidioides. Vegetation ranges from sparse to relatively thick cover in lower Sonoran deserts, Chaparral-upper Sonoran brush and grasslands, and Mediterranean savannas and forested foothills. No particular grass, shrub, or forb is definitive. Material classified as very fine sand and silt is abundant in all of the Coccidioides-bearing soils and may be their most common shared feature. Clays are not abundant (less than 10%). All of the examined soil locations are noteworthy as generally 50% of the individuals who were exposed to the dust or were excavating dirt at the sites were infected. Coccidioides has persisted in the soil at a site in Dinosaur National Monument, Utah for 37 years and at a Tucson, Arizona site for 41 years. ?? 2007 New York Academy of Sciences.

Conference Paper↗