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At least 1,261 records · Page 70Linked to original sources
USGS2003

Basal metabolism of the black-footed ferret (Mustela nigripes) and the Siberian polecat (M. eversmannii)

Black-footed ferrets ( Mustela nigripes ) and Siberian polecats ( M. eversmannii ) are medium-sized (about 1 kg) mustelids with similar ecological and morphological characteristics. We measured basal metabolic rates (BMR) for both species. In contrast with the commonly stated belief that mustelids have relatively high mass-specific BMR, neither the BMR of ferrets nor that of polecats in winter was greater than standard allometric predictions for all mammals. As suggested by previous authors, we believe that our relatively lower measurements for BMR are due to our efforts to minimize stress during the experimental procedure. These results support the contention that BMR in mustelids is no different from what is expected of mammals of this body mass. Seasonal differences were found in polecat BMR (higher in summer) but not in ferret BMR. Reasons for this interspecific difference may relate to differences in natural histories of these species.

Journal of Mammalogy↗
USGS2021

Exploiting the physiology of lampreys to refine methods of control and conservation

Lampreys (order: Petromyzontiformes) represent one of two extant groups of jawless fishes, also called cyclostomes. Lampreys have a variety of unique features that distinguish them from other fishes. Here we review the physiological features of lampreys that have contributed to their evolutionary and ecological success. The term physiology is used broadly to also include traits involving multiple levels of biological organization, like swimming performance, that have a strong but not exclusively physiological basis. We also provide examples of how sea lamprey traits are currently being used or investigated to control invasive populations in the Great Lakes, such as reduced capacity to detoxify lampricides, inability to surmount low barriers or dams, and sensitivity to several lamprey-specific chemosensory pheromones and alarm cues. Specific suggestions are also provided for how an improved knowledge of lamprey physiological traits could be exploited for more effective conservation of native lampreys and lead to the development of next generation sea lamprey control and conservation tools.

Journal of Great Lakes Research↗
USGS2006

The western pond turtle (Clemmys marmorata) in the Mojave River, California, USA: Highly adapted survivor or tenuous relict?

Aspects of the ecology of populations of the western pond turtle Clemmys marmorata were investigated in the Mojave River of the central Mojave Desert, California, U.S.A. One population occupied man-made ponds and the other occurred in natural ponds in the flood plain of the Mojave River. Both habitats are severely degraded as a result of ground water depletion from human activities along the river and one is infested with the exotic shrub saltcedar Tamarix ramosissima . Mean female carapace length (CL) was significantly greater (14.4 cm) than that of males (13.7 cm). Live juveniles were not detected during the period of study. Shelled eggs were visible in X-radiographs from 26 May to 14 July. Mean clutch size was 4.46 and ranged from 3 to 6 eggs. Clutch size did not vary between 1998 and 1999 but was significantly correlated with CL for both years combined, increasing at the rate of 0.548 eggs/cm CL. Gravid female CL ranged from 13.3–16.0 cm. Some females nested in both years. Mean X-ray egg width (21.8 mm) was not significantly correlated with CL or clutch size. X-ray egg width differed more among clutches than within, whether including CL as a co-variate or not. Nesting migrations occurred from 6 June to 8 July with minimum round trip distances ranging from 17.5–585 m with a mean of 195 m. Mean estimated time of departure as measured at the drift fence was 18:13. Most females returned to the ponds in the early morning. Nesting migrations required females to be out of the water for estimated periods of 0.83 to 86 h. The destination of nesting females was typically fluvial sand bars in the channel of the dry riverbed. Overall, the ecology of C. marmorata in the Mojave River is very similar to that reported for populations in less severe habitats along the west coast of the United States. Notable exceptions include long nesting migrations to sandbars in the dry river channel, a possible result of human modifications to the environment, and an apparent lack of terrestrial overwintering behaviour in Mojave River populations. The general similarity of desert and coastal populations is possibly a reflection of their recent geographic separation. Overall, populations in the Mojave River exhibit few obvious adaptations to living in the desert and are considered to be tenuous relicts of the Pleistocene. The small size and tenuous status of these populations suggests that immediate conservation action is needed, including establishment of satellite populations as a hedge against extirpation.

California↗
USGS2010

Visual implant elastomer mark retention through metamorphosis in amphibian larvae

Questions in population ecology require the study of marked animals, and marks are assumed to be permanent and not overlooked by observers. I evaluated retention through metamorphosis of visual implant elastomer marks in larval salamanders and frogs and assessed error in observer identification of these marks. I found 1) individual marks were not retained in larval wood frogs ( Rana sylvatica ), whereas only small marks were likely to be retained in larval salamanders ( Eurycea bislineata ), and 2) observers did not always correctly identify marked animals. Evaluating the assumptions of marking protocols is important in the design phase of a study so that correct inference can be made about the population processes of interest. This guidance should be generally useful to the design of mark–recapture studies, with particular application to studies of larval amphibians.

Journal of Wildlife Management↗
USGS2024

Serologic survey of selected arthropod-borne pathogens in free-ranging snowshoe hares (Lepus americanus) captured in Northern Michigan, USA

Snowshoe hares ( Lepus americanus ) in the Upper Peninsula (UP) of Michigan, USA, occupy the southern periphery of the species' range and are vulnerable to climate change. In the eastern UP, hares are isolated by the Great Lakes, potentially exacerbating exposure to climate-change-induced habitat alterations. Climate change is also measurably affecting distribution and prevalence of vector-borne pathogens in North America, and increases in disease occurrence and prevalence can be one signal of climate-stressed wildlife populations. We conducted a serosurvey for vector-borne pathogens in snowshoe hares that were captured in the Hiawatha National Forest in the eastern UP of Michigan, USA, 2016-2017. The most commonly detected antibody response was to the mosquito-borne California serogroup snowshoe hare virus (SSHV). Overall, 24 (51%) hares screened positive for SSHV antibodies and of these, 23 (96%) were confirmed positive by plaque reduction neutralization test. We found a positive association between seroprevalence of SSHV and live weight of snowshoe hares. Additionally, we detected a significant effect of ecological land type group on seroprevalence of SSHV, with strong positive support for a group representing areas that tend to support high numbers of hares (i.e., acidic mineral containing soils with cedar, mixed swamp conifers, tamarack and balsam fir as common overstory vegetation). We also detected and confirmed antibodies for Jamestown Canyon virus and Silverwater virus in a single hare each. We did not detect antibodies to other zoonotic vector-borne pathogens, including Lacrosse encephalitis virus, West Nile virus, Borrelia burgdorferi, Powassan virus, and Francisella tularensis. These results provide a baseline for future serological studies of vector-transmitted diseases that may increase climate vulnerability of snowshoe hares in the UP of Michigan, as well as pose a climate-related zoonotic risk.

Michigan↗
USGS2021

Remote ecological monitoring with smartphones and tasker

Researchers have increasingly used autonomous monitoring units to record animal sounds, track phenology with timed photographs, and snap images when triggered by motion. We piloted the use of smartphones to monitor wildlife in the Riverside East Solar Energy Zone (California) and at Indiana Dunes National Park (Indiana). For both efforts, we established remote autonomous monitoring stations in which we housed an Android smartphone in a weather-proof box mounted to a pole and powered by solar panels. We connected each smartphone to a Google account, and the smartphone received its recording/photo schedule daily via a Google Calendar connection when in data transmission mode. Phones were automated by Tasker, an Android application for automating cell phone tasks. We describe a simple approach that could be adopted by others who wish to use nonproprietary methods of data collection and analysis.

California, Indiana↗
USGS2015

Variation in the myosoricine hand skeleton and its implications for locomotory behavior (Eulipotyphla: Soricidae)

Substrate use and locomotory behavior of mammals are typically reflected in external characteristics of the forefeet, such as the relative proportions of the digits and claws. Although skeletal anatomy of the forefeet can be more informative than external characters, skeletons remain rare in systematic collections. This is particularly true for the Myosoricinae (Eulipotyphla: Soricidae), a small clade of African shrews that includes both ambulatory forest shrews ( Myosorex ) and semifossorial mole shrews ( Surdisorex ). Most species in this subfamily have restricted distributions, and their behavior and ecology are mostly unstudied. To better understand the potential range of locomotory behavior among myosoricines, we used digital x-rays to image and facilitate measuring the forefoot skeletons of 9 species. As a gauge of potential variation, we compared them with the ambulatory talpid Uropsilus (Talpidae) and the semifossorial talpid Neurotrichus . The hand morphologies of myosoricines show a graded range of potential substrate use between ambulatory and semifossorial. Some of these shrews exhibit adaptations for increased burrowing efficiency that are similar to those seen in talpids and other mammals, such as longer, broader distal phalanges and claws and shorter, wider metacarpals and proximal and middle phalanges. They also, however, have characteristics that are distinct from talpids, such as maintenance of forefoot asymmetry and an increased emphasis of ray III.

Journal of Mammalogy↗
USGS2003

Application of a multipurpose unequal probability stream survey in the Mid-Atlantic Coastal Plain

A stratified, spatially balanced sample with unequal probability selection was used to design a multipurpose survey of headwater streams in the Mid-Atlantic Coastal Plain. Objectives for the survey include unbiased estimates of regional stream conditions, and adequate coverage of unusual but significant environmental settings to support empirical modeling of the factors affecting those conditions. The design and field application of the survey are discussed in light of these multiple objectives. A probability (random) sample of 175 first-order nontidal streams was selected for synoptic sampling of water chemistry and benthic and riparian ecology during late winter and spring 2000. Twenty-five streams were selected within each of seven hydrogeologic subregions (strata) that were delineated on the basis of physiography and surficial geology. In each subregion, unequal inclusion probabilities were used to provide an approximately even distribution of streams along a gradient of forested to developed (agricultural or urban) land in the contributing watershed. Alternate streams were also selected. Alternates were included in groups of five in each subregion when field reconnaissance demonstrated that primary streams were inaccessible or otherwise unusable. Despite the rejection and replacement of a considerable number of primary streams during reconnaissance (up to 40 percent in one subregion), the desired land use distribution was maintained within each hydrogeologic subregion without sacrificing the probabilistic design.

Journal of the American Water Resources Associatio↗
USGS2018

Biomonitoring using invasive species in a large Lake: Dreissena distribution maps hypoxic zones

Due to cultural eutrophication and global climate change, an exponential increase in the number and extent of hypoxic zones in marine and freshwater ecosystems has been observed in the last few decades. Hypoxia, or low dissolved oxygen (DO) concentrations, can produce strong negative ecological impacts and, therefore, is a management concern. We measured biomass and densities of Dreissena in Lake Erie, as well as bottom DO in 2014 using 19 high frequency data loggers distributed throughout the central basin to validate a three-dimensional hydrodynamic-ecological lake model. We found that a deep, offshore hypoxic zone was formed by early August, restricting the Dreissena population to shallow areas of the central basin. Deeper than 20 m, where bottom hypoxia routinely develops, only young of the year mussels were found in small numbers, indicating restricted recruitment and survival of young Dreissena . We suggest that monitoring Dreissena distribution can be an effective tool for mapping the extent and frequency of hypoxia in freshwater. In addition, our results suggest that an anticipated decrease in the spatial extent of hypoxia resulting from nutrient management has the potential to increase the spatial extent of profundal habitat in the central basin available for Dreissena expansion.

Lake Erie↗
USGS2022

Stakeholder engagement to guide decision-relevant water data delivery

Water resources management and policy making require access to reliable scientific data. However, water managers may need to overcome various obstacles to accessing data. For example, insufficient technological infrastructures, low data literacy, and data format complexities often inhibit data user access. Thus, it is imperative to include stakeholders in the design of data delivery systems. The United States Geological Survey's Water Resources Mission Area is currently developing Integrated Water Availability Assessments (IWAAs) — multi-extent, stakeholder driven, near real-time water availability census and prediction for human and ecological uses. To provide appropriate user accessibility to data delivery systems developed for IWAAs, a user-centered design process including stakeholder focus groups was used to determine potential water data user needs and preferences. Focus groups identified five types of potential users: Public sector water resources managers, Public sector water resources manager data analysts, Industry and private companies, Tribal Nations, and Nonprofit organizations. Different water data user types depended on diverse spatial and temporal scale data. Public sector water resources managers benefitted most from data synthesized into user-friendly platforms and Public sector water resources data analysts preferred easy access to raw data. These findings can support the development of a water data delivery platform that meets a variety of user needs.

Journal of the American Water Resources Associatio↗
USGS2009

Assessment tools for urban catchments: developing biological indicators based on benthic macroinvertebrates

Biological indicators, particularly benthic macroinvertebrates, are widely used and effective measures of the impact of urbanization on stream ecosystems. A multimetric biological index of urbanization was developed using a large benthic macroinvertebrate dataset (n = 1,835) from the Baltimore, Maryland, metropolitan area and then validated with datasets from Cleveland, Ohio (n = 79); San Jose, California (n = 85); and a different subset of the Baltimore data (n = 85). The biological metrics used to develop the multimetric index were selected using several criteria and were required to represent ecological attributes of macroinvertebrate assemblages including taxonomic composition and richness (number of taxa in the insect orders of Ephemeroptera, Plecoptera, and Trichoptera), functional feeding group (number of taxa designated as filterers), and habit (percent of individuals which cling to the substrate). Quantile regression was used to select metrics and characterize the relationship between the final biological index and an urban gradient (composed of population density, road density, and urban land use). Although more complex biological indices exist, this simplified multimetric index showed a consistent relationship between biological indicators and urban conditions (as measured by quantile regression) in three climatic regions of the United States and can serve as an assessment tool for environmental managers to prioritize urban stream sites for restoration and protection.

Journal of the American Water Resources Associatio↗
USGS1999

Genetic and morphometric assessment of an unusual tortoise (Gopherus agassizii) population in the Black Mountains of Arizona

Under recent regulatory designation of the U.S. Fish and Wildlife Service, desert tortoises (Gopherus agassizii) occurring east and south of the Colorado River constitute the Sonoran population, whereas those to the west and north form the Mojave population. These management units, distinguished by significant genetic, morphometric, and ecological differences, represent deep phylogenetic subdivisions within G. agassizii and are of high conservation value. We provide genetic and morphological profiles for an unusual tortoise population inhabiting the Black Mountains of Arizona, some 40 km east of the Colorado River. Both mitochondrial (mt) DNA and morphometric analyses revealed predominately Mojavean features: ten of eleven Black Mountain tortoises possessed Mojave mtDNA markers, and 24 of 37 animals exhibited Mojave morphometric phenotypes. Our results indicate west-to-east movement of tortoises across the Colorado River, though how or when a Mojave lineage became established in the Black Mountains is difficult to ascertain. Active dispersal, river meander, and human transport (early or modern peoples) serve as plausible explanations. Future management of the Black Mountain tortoises should emphasize the population's Mojavean affinities.

Journal of Herpetology↗
USGS2020

Development and testing of species-specific quantitative PCR assays for environmental DNA applications

New, non-invasive methods for detecting and monitoring species presence are being developed to aid in fisheries and wildlife conservation management. The use of environmental DNA (eDNA) samples for detecting macrobiota is one such group of methods that is rapidly becoming popular and being implemented in national management programs. Here we focus on the development of species-specific targeted assays for probe-based quantitative PCR (qPCR) applications. Using probe-based qPCR offers greater specificity than is possible with primers alone. Furthermore, the ability to quantify the amount of DNA in a sample can be useful in our understanding of the ecology of eDNA and the interpretation of eDNA detection patterns in the field. Careful consideration is needed in the development and testing of these assays to ensure the sensitivity and specificity of detecting the target species from an environmental sample. In this protocol we will delineate the steps needed to design and test probe-based assays for the detection of a target species; including creation of sequence databases, assay design, assay selection and optimization, testing assay performance, and field validation. Following these steps will help achieve an efficient, sensitive, and specific assay that can be used with confidence. We demonstrate this process with our assay designed for populations of the mucket ( Actinonaias ligamentina ), a freshwater mussel species found in the Clinch River, USA.

JOVE Journal Of Visualized Experiments↗
USGS1990

A sensitivity analysis of nine diversity and seven similarity indices

Indices summarizing community structure are used to evaluate fundamental community ecology, species interaction, biogeographical factors, and environmental stress. Some of these indices are insensitive to gross community changes induced by contaminants of pollution. Sixteen indices commonly used to assess the status of aquatic communities in water quality studies were evaluated using computer simulation techniques to determine specific index responses. Three communities of different initial structure (19 species, 38 species, and 83 species) were generated using the lognormal equation. Each community was then perturbed in three ways: common species disproportionally reduced, all species proportionally reduced, and rare species disproportionally reduced. The behavior of the indices was analyzed graphically and differential response due to initial community structure and type of community change was documented. Some recommendations of potential sources of error using community levels indices were developed.

Research Journal of the Water Pollution Control Fe↗
USGS1983

Distribution and ecology of marine turtles in waters off the southeastern United States

Aerial surveys of marine waters up to 222 km from shore in the Gulf of Mexico and nearby Atlantic Ocean suggest that marine turtles are largely distributed in waters less than 100 m in depth. The loggerhead turtle (Caretta caretta) was observed nearly 50 times as often in waters off eastern and western Florida as in the western Gulf of Mexico. Loggerheads were present year round but the frequency of sightings in the winter months was lower than at other seasons. Green turtles (Chelonia rnydas) were infrequently observed but were most conspicuous in waters off eastern Florida. Kemp's ridleys (Lepidochelys kempi) were most frequently sighted off southwestern Florida and rarely observed in the western Gulf of Mexico. Leatherback turtles (Dermochelys coriacea) were more conspicuous on the continental shelf than in adjacent deeper waters. A concentration of leatherback and loggerhead turtles occurred west of the Gulf Stream Current in August 1980, near Brevard County, Florida.

Journal of Herpetology↗
USGS2011

Luring anglers to enhance fisheries

Current fisheries management is, unfortunately, reactive rather than proactive to changes in fishery characteristics. Furthermore, anglers do not act independently on waterbodies, and thus, fisheries are complex socio-ecological systems . Proactive management of these complex systems necessitates an approach—adaptive fisheries management—that allows learning to occur simultaneously with management. A promising area for implementation of adaptive fisheries management is the study of luring anglers to or from specific waterbodies to meet management goals. Purposeful manipulation of anglers, and its associated field of study, is nonexistent in past management. Evaluation of different management practices (i.e., hypotheses) through an iterative adaptive management process should include both a biological and sociological survey to address changes in fish populations and changes in angler satisfaction related to changes in management. We believe adaptive management is ideal for development and assessment of management strategies targeted at angler participation. Moreover these concepts and understandings should be applicable to other natural resource users such as hunters and hikers.

Journal of Environmental Management↗
USGS2017

Simulation of rapid ecological change in Lake Ontario

Lower trophic level processes are integral to proper functioning of large aquatic ecosystems and have been disturbed in Lake Ontario by various stressors including exotic species. The invasion of benthic habitats by dreissenid mussels has led to systemic changes and native faunal declines. Size-dependent physiological rates, spatial differences and connectivity, competition, and differential population dynamics among invertebrate groups contributed to the change and system complexity. We developed a spatially explicit, individual-based mechanistic model of the benthic ecosystem in Lake Ontario, with coupling to the pelagic system, to examine ecosystem dynamics and effects of dreissenid mussel invasion and native fauna losses. Benthic organisms were represented by functional groups; filter-feeders (i.e., dreissenid mussels), surface deposit-feeders (e.g., native amphipod Diporeia spp.), and deposit-feeders (e.g., oligochaetes and other burrowers). The model was stable, represented ecological structure and function effectively, and reproduced observed effects of the mussel invasion. Two hypotheses for causes of Diporeia loss, competition or disease-like mortality, were tested. Simple competition for food did not explain observed declines in native surface deposit-feeders during the filter-feeder invasion. However, the elevated mortality scenario supports a disease-like cause for loss of the native amphipod, with population changes in various lake areas and altered benthic biomass transfers. Stabilization of mussel populations and possible recovery of the native, surface-deposit feeding amphipod were predicted. Although further research is required on forcing functions, model parameters, and natural conditions, the model provides a valuable tool to help managers understand the benthic system and plan for response to future disruptions.

Lake Ontario↗
USGS1993

Ecologically correlated morphological variation in tadpoles of the leopard frog, Rana chiricahuensis

Interspecific differences in tadpole morphology among leopard frogs of the Rana pipiens complex may represent adaptations to larval habitats. We documented variation in tadpole morphology among populations of R. chiricahuensis and compared intraspecific patterns of variation to those among species. Traits that exhibit similar patterns of variation in intraspecific and interspecific comparisons may represent adaptations to different larval habitats. Tadpoles of R. chiricahuensis found in streams have more contrasting melanic patterns on the tail, thicker dorsal fins, and somewhat larger tail muscles than those from ponds. Unexpected differences between tadpoles from two stream habitats might represent nonadaptive morphological variation. Alternatively, such differences may represent different morphological responses to similar selection pressures, to subtly different aquatic habitats (different selective regimes), or different developmental responses to different environmental cues. Parallels in variation for some morphological traits within and among tadpoles of leopard frog species support, but do not demonstrate, the contention that those morphological differences represent adaptations to larval habitats.

Journal of Herpetology↗