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At least 1,315 records · Page 73Linked to original sources
USGS2012

Red-tailed Hawk movements and use of habitat in the Luquillo Mountains of Puerto Rico

The Red-tailed Hawk ( Buteo jamaicensis ) is a top predator of upland ecosystems in the Greater Antilles. Little information exists on the ecology of the insular forms of this widely distributed species. We studied movements and resource use of the Red-tailed Hawk from 2000 to 2002 in the montane forests of northeastern Puerto Rico. We captured 32 and used 21 radio-marked Red-tailed Hawks to delineate home range, core area shifts, and macrohabitat use in the Luquillo Mountains. Red-tailed Hawks in the Luquillo Mountains frequently perched near the top of canopy emergent trees and were characterized by wide-ranging capabilities and extensive spatial overlap. Home range size averaged 5,022.6 ± 832.1 ha (305–11,288 ha) and core areas averaged 564.8 ± 90.7 ha (150–1,230 ha). This species had large mean weekly movements (3,286.2 ± 348.5 m) and a preference for roadside habitats. Our findings suggest fragmentation of contiguous forest outside protected areas in Puerto Rico may benefit the Red-tailed Hawk.

Puerto Rico↗
USGS2017

Satellite-tagged osprey nearly sets longevity record and productivity response to initial captures

We equipped adult Ospreys ( Pandion haliaetus ) from 24 nests in Oregon/Washington with satellite-tracked battery-powered radios, known as platform transmitter terminals (PTTs), in 1996–1999. These Ospreys from the lower Columbia River (river miles 76–286), and the Willamette Valley in western Oregon were part of a larger study of Osprey fall migration, wintering ecology, and spring migration, which included additional adults from the Upper Midwest and East Coast of the United States ( Martell et al. 2001 , 2014 , Washburn et al. 2014 ). These early-generation PTTs weighed 30–35 g (Microwave Telemetry Inc., Columbia, MD U.S.A.) and utilized the ARGOS tracking system ( www.argos-system.org ). We placed PTTs on the birds' backs using Teflon ribbon (Bally Ribbon, Bally, PA U.S.A.) in a standard backpack configuration ( Kenward 2001 ). With the mass of adult male Ospreys 1400 to 1500 g ( Poole et al. 2002 ), the ratio of tag mass to body mass was 2.0 to 2.5%. Ospreys also received a standard size 8 bird band (U.S. Geological Survey) on one leg and a numbered color band on the other. For more details on trapping techniques, attachment procedures, the battery-powered units, turn-on, turn-off cycles, and tracking equipment, see Martell et al. (2001) .

Oregon, Washington↗
USGS1982

Some observations on the ecology and fish management of reservoirs in the United States

By 1980 there were 1,608 reservoirs (over 202 ha each) with a surface area of 4 million ha in the United States. Construction of new reservoirs has decreased in recent years because of the lack of suitable sites and the opposition of environmental interests. Reservoirs have characteristics of both lacustrine and riverine ecosystems. Reservoirs have been segmented into riverine, transitional and lacustrine zones for simulation modelling.Fish and plankton production increases rapidly after initial impoundment and then decreases and stabilizes at lower levels. Decreases in the number of fish species and in fish biomass following impoundment are caused by reduced quantity and quality of spawning and nursery habitat and decreased detrital input. Plankton populations can be followed downstream in a series of reservoirs and increases in abundance were associated with the inundation of vegetation or the introduction of nutrients.In addition to water level management, the most effective fish management programs have included introducing new fishes, developing vegetation or building structures on the reservoir bottom. Considerable progress has been made in predicting the effects of environmental parameters on fish production.

Montana, Nebraska, North Dakota, South Dakota↗
USGS2004

Differential propagation of the metazoan parasite Myxobolus cerebralis by Limnodrilus hoffmeisteri, Ilyodrilus templetoni, and genetically distinct strains of Tubifex tubifex

Whirling disease, caused by the parasite Myxobolus cerebralis, has infected rainbow trout (Oncorhynchus mykiss) and other salmonid fish in the western United States, often with devastating results to native populations but without a discernible spatial pattern. The parasite develops in a complex 2-host system in which the aquatic oligochaete Tubifex tubifex is an obligate host. Because substantial differences in whirling disease severity in different areas of North America did not seem explainable by environmental factors or features of the parasite or its fish host, we sought to determine whether ecological or genetic variation within oligochaete host populations may be responsible. We found large differences in compatibility between the parasite and various laboratory strains of T. tubifex that were established from geographic regions with different whirling disease histories. Moreover, 2 closely related species of tubificids, Limnodrilus hqffmeisteri and Ilyodrilus templetoni, which occur naturally in mixed species assemblages with T. tubifex, were incompatible with M. cerebralis. Virulence of the parasite was directly correlated with the numbers of triactinomyxon spores that developed within each strain of T. tubifex. Thus, the level of virulence was directly related to the compatibility between the host strain and the parasite. Genetic analyses revealed relationships that were in agreement with the level of parasite production. Differences in compatibilities between oligochaetes and M. cerebralis may contribute to the spatial variance in the severity of the disease among salmonid populations. ?? American Society of Parasitologists 2004.

Journal of Parasitology↗
USGS2019

The influence of layout on Appalachian Trail soil loss, widening, and muddiness: Implications for sustainable trail design and management

This research investigates the influence of layout and design on the severity of trail degradation. Previous trail studies have been restricted by relatively small study areas which provide a limited range of environmental conditions and therefore produce findings with limited applicability; this research improves on this limitation by analyzing a representative sample of the Appalachian Trail with significant topographical, ecological, use-related, and managerial diversity. Many trail science studies have also focused on a singular form of trail degradation, whereas this study investigates all three core types of trail impact: trail soil loss, widening and muddiness. Relational analyses with all three indicators provide a more cohesive understanding of trail impact and reveal interrelationships between trail degradation processes. ANOVA testing of the mean values for these trail impact indicators across categories of influential independent factors confirms and refines the relevance of core trail design principles, specifically the sustainability advantages of trails with low grades and side-hill alignments. Findings also reveal and clarify the importance of landform grade in determining the susceptibility of trails to degradation and the influence of routing decisions; these relationships have received relatively little attention in the literature. The results also reveal several methodological considerations for trail alignment metrics and trail impact indicators

Connecticut, Georgia, Maine, Massachusetts, Maryla↗
USGS2007

The FORE-SCE model: a practical approach for projecting land cover change using scenario-based modeling

A wide variety of ecological applications require spatially explicit, historic, current, and projected land use and land cover data. The U.S. Land Cover Trends project is analyzing contemporary (1973–2000) land-cover change in the conterminous United States. The newly developed FORE-SCE model used Land Cover Trends data and theoretical, statistical, and deterministic modeling techniques to project future land cover change through 2020 for multiple plausible scenarios. Projected proportions of future land use were initially developed, and then sited on the lands with the highest potential for supporting that land use and land cover using a statistically based stochastic allocation procedure. Three scenarios of 2020 land cover were mapped for the western Great Plains in the US. The model provided realistic, high-resolution, scenario-based land-cover products suitable for multiple applications, including studies of climate and weather variability, carbon dynamics, and regional hydrology.

Journal of Land Use Science↗
USGS2013

Multi-scale and nested-intensity sampling techniques for archaeological survey

This paper discusses sampling techniques for archaeological survey that are directed toward evaluating the properties of surface artifact distributions. The sampling techniques we experimented with consist of a multi-scale sampling plot developed in plant ecology and the use of a nested-intensity survey design. We present results from the initial application of these methods. The sampling technique we borrowed from plant ecology is the Modified-Whittaker multiscale sampling plot, which gathers observations at the spatial scales of 1 sq m, 10 sq m, 100 sq m, and 1000 sq m. Nested-intensity surveys gather observations on the same sample units at multiple resolutions. We compare the results of a closely-spaced walking survey, a crawling survey, and a test excavation to a depth of 10 cm. These techniques were applied to ten 20 × 50 m survey plots distributed over an area of 418 ha near the Hudson-Meng Bison Bonebed in NW Nebraska. These approaches can significantly improve the accuracy of survey data. Our results show that high-resolution coverage techniques overlook more material than archaeologists have suspected. The combined approaches of multi-scale and nested-intensity sampling provide new tools to improve our ability to investigate the properties of surface records.

Journal of Field Archaeology↗
USGS1991

Energy dynamics, foraging ecology, and behavior of prenesting greater white-fronted geese

We collected greater white-fronted geese (Anser albifrons frontalis) on their nesting grounds on the Yukon-Kuskokwim Delta, Alaska, when they arrived and again before incubation during 1986 and 1987. Body mass, water content, crude fat, and crude protein increased in female geese between arrival and incubation onset in 1986 and 1987 (P = 0.0001, 0.0002, 0.0329, and 0.0003, respectively). Body mass of male geese during prenesting did not change, but total fat content decreased by about 30%. Crude protein of males was different between years (P = 0.0014). Female geese spent more time feeding than did males (P < 0.001). Primary foods during the prenesting period were pendent grass (Arctophila fulva) shoots and arrowgrass (Triglochin palustris) bulbs. Gizzard contents and orifice staining indicated crowberries (Empetrum nigrum) also were consumed. Of the commonly consumed food items, arrowgrass bulbs had the greatest protein content (21%), and crowberries had the greatest lipid content (10%). Unlike other medium-sized, northern-nesting geese, food (energy) acquired on the nesting grounds by white-fronted geese before incubation increased endogenous reserves necessary for reproduction.

Journal of Wildlife Management↗
USGS2017

Basis function models for animal movement

Advances in satellite-based data collection techniques have served as a catalyst for new statistical methodology to analyze these data. In wildlife ecological studies, satellite-based data and methodology have provided a wealth of information about animal space use and the investigation of individual-based animal–environment relationships. With the technology for data collection improving dramatically over time, we are left with massive archives of historical animal telemetry data of varying quality. While many contemporary statistical approaches for inferring movement behavior are specified in discrete time, we develop a flexible continuous-time stochastic integral equation framework that is amenable to reduced-rank second-order covariance parameterizations. We demonstrate how the associated first-order basis functions can be constructed to mimic behavioral characteristics in realistic trajectory processes using telemetry data from mule deer and mountain lion individuals in western North America. Our approach is parallelizable and provides inference for heterogenous trajectories using nonstationary spatial modeling techniques that are feasible for large telemetry datasets. Supplementary materials for this article are available online.

Journal of the American Statistical Association↗
USGS2016

Disease epidemics: Lessons for resilience in an increasingly connected world

In public health, the term resilience often refers to the personality traits that individuals possess which help them endure and recover from stressors. However, resilience as a system characteristic, especially in regards to complex social-ecological systems, can be informative for public health at scales larger than the individual. Acute shocks to systems occur against a background of existing conditions, which are crucial determinants of the eventual public health outcomes of those shocks, and in the context of complex dependencies among and between ecological and societal elements. Many components of a system's baseline condition are chronic public health concerns themselves and diminish the capacity of the system to perform in the face of acute shocks. The emerging field of resilience management is concerned with holistically assessing and improving a system's ability to prepare for and absorb disruption, and then recover and adapt across physical, information, environmental and social domains. Integrating resilience considerations into current risk- and evidence-based approaches to disease control and prevention 1 can move public health efforts toward more proactive and comprehensive solutions for protecting and improving the health of communities. Here, we look to the case of the Black Death as an illustrative case of a dramatic transformation in human history, an acute shock to a system that was underlain by chronic social maladies, to derive lessons about resilience management for public health in contemporary systems.

Journal of Public Health↗
USGS2021

Summer Diet of Juvenile Lake Sturgeon Reintroduced into the Genesee and St. Regis Rivers, New York USA

The restoration of threatened species involves understanding multiple aspects of the life history and ecology of the target species. One important consideration in the restoration of threatened species is feeding ecology. We examined the summer diet of reintroduced juvenile lake sturgeon ( Acipenser fulvescens ) in the Genesee ( n = 119, ages 1 and 2) and the St. Regis rivers ( n = 40, ages 1, 2, 5, 6, and 7) of New York State, USA, in the summer of 2005. The most common taxa consumed were Diptera (88% of prey biomass) in the Genesee River and Ephemeroptera (35% of prey biomass) and Diptera (29%) in the St. Regis River. Diptera: (Chironomidae) was the major prey taxon in both benthic communities. Selectivity analysis showed a positive selection of Diptera by Genesee River lake sturgeon and an avoidance of Diptera by St. Regis River lake sturgeon. The St. Regis River lake sturgeon showed avoidance of Coleoptera, but positive selection of Ephemeroptera, Trichoptera, and Oligochaeta. Results indicate that the reintroduced juvenile lake sturgeon are growing and successfully finding prey in these two rivers and appear to actively select specific prey types.

New York↗
USGS2020

Intrinsic prey preference and selection of the giant gartersnake: A threatened predator in a nonnative prey-dominated community

The introduction of exotic species into an environment can introduce great change in the trophic dynamics of native species. This is of even greater concern if the native species is of conservation concern. The giant gartersnake, Thamnophis gigas , an endemic predator of the Central Valley of California and a species of conservation concern at the state and federal levels, has declined as a result of conversion of its once vast wetland habitat to agriculture. Another anthropogenic factor contributing to this snake's changing ecology is the introduction of nonnative prey into the species' habitats. These introductions have resulted in a prey community that is almost completely composed of exotic species and have potential for considerable effects. In order to assess prey preference and selection we performed three sets of behavioral trials on naïve neonates. We examined 1) neonate prey preference in response to olfactory cues of prepared prey extracts, 2) neonate consumption of different live prey items presented simultaneously; and 3) terrestrial feeding behavior and/or latency to successful attack. Results from the olfactory study suggest that native Sierran treefrogs, Pseudacris sierra, are preferred by neonates. Results from consumption trials suggest that neonates are more likely to select frog species than fish species. This is the first study that we are aware of that examines prey selection of this threatened species and serves to inform its conservation and management.

Journal of Fish and Wildlife Management↗
USGS2022

Suppression of invasive fish in the west: Synthesis and suggestions for improvement

Reservoirs are ubiquitous features on the landscape of the western United States. Although reservoirs provide numerous benefits (e.g., irrigation, flood control, hydropower, recreational use), these systems are often a concern from an ecological perspective. Reservoirs support fisheries primarily composed of nonindigenous sport fishes that may become invasive and negatively influence recipient ecosystems. Furthermore, reservoirs alter adjacent riverine habitats, further increasing the threat of invasive fishes to aquatic systems. As such, most western natural resource management agencies focus considerable effort on managing the threat of invasive fish species. Unfortunately, controlling invasive fish is expensive and rarely effective because of a lack of clear objectives, appropriate fishing mortality, and long-term commitment. In an effort to improve management of invasive fish in the western United States, we reviewed existing literature to identify the steps necessary to effectively suppress these species. Specifically, we provide guidance on defining achievable objectives, assessing feasibility, evaluating success, and improving the efficiency of invasive fish suppression. This iterative approach provides managers with a framework to effectively address the challenge of suppressing invasive fish in the western United States.

North American Journal of Fisheries Management↗
USGS2020

Uptake, metabolism, and elimination of fungicides from coated wheat seeds in Japanese quail (Coturnix japonica)

Pesticides coated to the seed surface potentially pose an ecological risk to granivorous birds that consume incompletely buried or spilled seeds. To assess the toxicokinetics of seeds treated with current-use fungicides, Japanese quail (Coturnix japonica) were orally dosed with commercially coated wheat seeds. Quail were exposed to metalaxyl, tebuconazole, and fludioxonil at either a low (0.07, 0.03, and 0.03 mg/kg body weight) or high dose (0.2, 0.09, and 0.1 mg/kg body weight). Fungicides were rapidly absorbed and distributed to tissues. Tebuconazole was metabolized into t-butylhydroxy-tebuconazole. All compounds were eliminated to below detection limits within 24 h. The high detection frequencies observed in fecal samples potentially offers a noninvasive matrix to monitor pesticide exposure. Summing total body burden across plasma, tissue, and fecal samples, less than 9% of the administered dose was identified as the parent fungicide, demonstrating the importance to monitor both active ingredients and their metabolites in biological samples.

Journal of Agricultural and Food Chemistry↗
USGS2019

Bioclimatic envelopes for individual demographic events driven by extremes: Plant mortality from drought and warming

The occurrence of plant species across the globe is largely constrained by climate. Ecologists use plant-climate relationships such as bioclimatic envelopes and related niche models to determine potential environmental conditions promoting probable species occurrence. Traditionally bioclimatic envelopes either exclude disturbance explicitly, or only include disturbance as infrequent and smaller scale processes, assuming that the net effect of climate parameters on key demographic processes predict longer-term equilibrial responses of biota. Due to increasing frequency and extent of extreme events associated with climate change, ecologists may need to increase focus on individual demographic events driven by environmental extremes such as widespread coral bleaching or large-scale tree die-off. An expanded focus on how extreme events catalyze individual demographic events would complement existing tools that predict long-term equilibrial biogeographic responses associated with long-term trends in climate. In many cases, extreme conditions (e.g. drought) are a necessary precursor for an abrupt demographic event (e.g. large-scale tree die-off) and the effects of extremes can be exacerbated by climatic trends (e.g. higher temperatures in combination with drought). Here, we highlight application of bioclimatic models for predicting individual demographic events. Defining the environmental conditions that precipitate demographic events such as widespread tree mortality is a necessary precursor for applying predictions to geographic space, and may require challenging biota with experiments that impose a combination of ecologically extreme conditions in one parameter and a shifting distribution in another (e.g. drought under higher temperatures). Currently data on conditions that drive individual demographic events associated with extremes are usually rare, aggregated across time, and/or correlative. We highlight this approach with a case study of drought-induced mortality in adult Pinus edulis trees that predicts a more than five-fold increase in frequency of die-off events under a global change scenario of high emissions. This general approach complements both traditional bioclimatic envelopes and more detailed physiological approaches currently being refined to address climate change challenges. Notably, this proposed approach could be developed for any climate condition or plant life stage, offering promise for improving predictions of individual demographic events that are rapidly altering ecosystems globally.

International Journal of Plant Sciences↗
USGS2010

Fall migration and habitat use of American woodcock in the central United States

Little is known about the migration ecology of the American woodcock (Scolopax minor). From 2001 to 2003, we began a 3-year study to document woodcock fall migration routes, rates, and habitat use from Minnesota, Wisconsin, and Michigan, USA. Some 586 radiomarked woodcock initiated migration. During 224 hours of aerial telemetry, we located 42 radiomarked woodcock in 6 states. Using locations of radiomarked birds, we speculated woodcock migration routes in the central United States. Stopover duration often exceeded 4 days, with some birds stopping longer than a week. Radiomarked birds were located in upland habitats more frequently than bottomland habitats, and used a higher proportion of mature forest than expected. A Geographic Information System was used to map potential woodcock habitat in the Central Region. Based on our results, we identified possible fall migration routes and priority areas for woodcock management in the Central Region. Our results should be used by land managers to prioritize future land acquisition and management of woodcock habitat.

Journal of Wildlife Management↗
USGS2022

Foraging ecology of Red-billed Tropicbird Phaethon aethereus in the Caribbean during early chick rearing revealed by GPS tracking

Investigating the foraging patterns of tropical seabirds can provide important information about their ocean habitat affinities as well as prey choice. Foraging studies of Red-billed Tropicbird Phaethon aethereus populations in the Caribbean are lacking. We sought to rectify this by opportunistically sampling regurgitates at nest sites on the island of St. Eustatius, Lesser Antilles, and by linking the GPS tracks of foraging adults to remotely sensed environmental variables. Diet samples were dominated by Exocoetidae (59.5%) and Belonidae (14.9%), although we were unable to identify 25.5% of samples due to digestion. Tropicbirds nesting on St. Eustatius exhibited diurnal foraging patterns, foraged in deeper waters with higher chlorophyll concentration, and consumed fewer Exocoetidae species compared to travelling behaviour. The maximum distance travelled from the colony was 953.7 km, with an average trip length of 176.8 (± 249.8) km. The biologged birds crossed multiple exclusive economic zones and marine protected areas, and on that basis, we suggest that efforts to protect and conserve this species may require transboundary collaboration throughout the wider Caribbean.

Marine Ornithology: Journal of Seabird Research an↗
USGS2022

African penguins and localized fisheries management: Response to Butterworth and Ross-Gillespie

We present a response to Butterworth and Ross-Gillespie's (2022) comment on our perspectives on how forage fish fisheries are impacting the endangered African penguin ( Sphenicus demersus ), and corresponding management options. Butterworth and Ross-Gillespie overstate model uncertainties and downplay the clear ecological and conservation significance of the fisheries closure experiment. We demonstrate that their criticism of “pseudo-replication” is weak, and not in line with their own analyses nor with the interpretations of many international scientific review panels commissioned by the government of South Africa to evaluate experimental results. Their comment does not alter our fundamental conclusions that forage fisheries operating near penguin breeding colonies compete with the birds for food resources, are detrimental to the penguin's population health, and are impeding recovery. Given that sardines are depleted (DFFE, 2021) and the African penguin is approaching a conservation crisis, we reiterate our position that continuing the precautionary approach of closures at the local scale of central-place foraging penguins is warranted to facilitate their population growth under fisheries management goals to conserve and maintain ecosystem functions.

ICES Journal of Marine Science↗