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At least 649 records · Page 36Linked to original sources
USGS2012

Linking river management to species conservation using dynamic landscape scale models

Efforts to conserve stream and river biota could benefit from tools that allow managers to evaluate landscape-scale changes in species distributions in response to water management decisions. We present a framework and methods for integrating hydrology, geographic context and metapopulation processes to simulate effects of changes in streamflow on fish occupancy dynamics across a landscape of interconnected stream segments. We illustrate this approach using a 482 km 2 catchment in the southeastern US supporting 50 or more stream fish species. A spatially distributed, deterministic and physically based hydrologic model is used to simulate daily streamflow for sub-basins composing the catchment. We use geographic data to characterize stream segments with respect to channel size, confinement, position and connectedness within the stream network. Simulated streamflow dynamics are then applied to model fish metapopulation dynamics in stream segments, using hypothesized effects of streamflow magnitude and variability on population processes, conditioned by channel characteristics. The resulting time series simulate spatially explicit, annual changes in species occurrences or assemblage metrics (e.g. species richness) across the catchment as outcomes of management scenarios. Sensitivity analyses using alternative, plausible links between streamflow components and metapopulation processes, or allowing for alternative modes of fish dispersal, demonstrate large effects of ecological uncertainty on model outcomes and highlight needed research and monitoring. Nonetheless, with uncertainties explicitly acknowledged, dynamic, landscape-scale simulations may prove useful for quantitatively comparing river management alternatives with respect to species conservation.

Georgia↗
USGS2015

Water-quality assessment of the Lower Grand River Basin, Missouri and Iowa, USA, in support of integrated conservation practices

The effectiveness of agricultural conservation programmes to adequately reduce nutrient exports to receiving streams and to help limit downstream hypoxia issues remains a concern. Quantifying programme success can be difficult given that short-term basin changes may be masked by long-term water-quality shifts. We evaluated nutrient export at stream sites in the 44 months that followed a period of increased, integrated conservation implementation within the Lower Grand River Basin. These short-term responses were then compared with export that occurred in the main stem and adjacent rivers in northern Missouri over a 22-year period to better contextualize any recent changes. Results indicate that short-term (October 2010 through May 2014) total nitrogen (TN) concentrations in the Grand River were 20% less than the long-term average, and total phosphorus (TP) concentrations were 23% less. Nutrient reductions in the short term were primarily the result of the less-than-average precipitation and, consequently, streamflow that was 36% below normal. Therefore, nutrient concentrations measured in tributary streams were likely less than normal during the implementation period. Northern Missouri streamflow-normalized TN concentrations remained relatively flat or declined over the period 1991 through 2013 likely because available sources of nitrogen, determined as the sum of commercial fertilizers, available animal manures and atmospheric inputs, were typically less than crop requirement for much of that time frame. Conversely, flow-normalized stream TP concentrations increased over the past 22 years in northern Missouri streams, likely in response to many years of phosphorus inputs in excess of crop requirements. Stream nutrient changes were most pronounced during periods that coincided with the major tillage, planting and growth phases of row crops and increased streamflow. Nutrient reduction strategies targeted at the period February through June would likely have the greatest impact on reducing nutrient export from the basin. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

River Research and Applications↗
USGS2006

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.

Regulated Rivers: Research & Management↗
USGS2014

Avian response to conservation buffers in agricultural landscapes during winter

Native herbaceous vegetation cover along row‐crop field edges (i.e., field buffers) increases breeding densities of many bird species. However, the effect of field buffers on bird species during the non‐breeding season is less understood. We compared density, avian richness, and avian conservation value on row‐crop fields containing buffers strategically designed for wildlife versus fields without buffers in 3 southeastern U.S. states during winter 2007 and 2008. Fields with buffers were enrolled in U.S. Department of Agriculture, Conservation Reserve Program practice Habitat Buffers for Upland Birds (CP33), which targets restoration of northern bobwhite ( Colinus virginianus ) and other upland bird species. Overall species richness did not differ on fields with buffers versus fields without buffers in 2007, but was 29% greater on fields with buffers in 2008. Swamp sparrows ( Melospiza georgiana ), song sparrows ( M. melodia ), field sparrows ( Spizella pusilla ), and red‐bellied woodpeckers ( Melanerpes carolinus ) had greater densities on fields with buffers compared with fields without buffers. Increasing field‐buffer width did not result in greater bird densities. Our results suggest a small change in primary land use (≈7%) produced a disproportionate population response by some grassland‐dependent and woodland bird species during winter. Because field buffers provide a direct source of winter food and cover resources, they may be a pragmatic means to provide critical non‐breeding habitat with little alteration of existing agricultural systems.

Arkansas, Kentucky, Mississippi↗
USGS2018

Density and success of upland duck nests in native‐ and tame‐seeded conservation fields

The Conservation Reserve Program (CRP) generates substantial benefits to continental duck populations by providing grassland nesting habitat in rested cropland. Seeding mixes of CRP grasslands vary among numerous conservation practices, but one contrast of interest in the Prairie Pothole Region is the use of introduced, or “tame” versus native grass. Although the benefits of CRP to duck populations are well‐known, relative values of these planting practices to nesting ducks have received little attention. Understanding differences in benefits to ducks due to planting practices would aid in prioritizing and selecting management practices for CRP and other restoration activities. We evaluated nest survival and density of ducks nesting in tame‐ and native‐seeded CRP fields in 36 study areas in the Prairie Pothole Region of North Dakota and South Dakota, USA, during 2002–2003. We searched for duck nests in 209 fields totaling 5,386 ha and found 2,941 nests. We found no support for differences in nest survival for any upland‐nesting duck species between fields seeded to tame versus native grass based on a design and analyses that accounted for spatial and temporal variation. Additionally, nest densities, adjusted for nest survival rates, of all duck species were similar between tame‐seeded and native‐seeded fields. We conclude that benefits to nesting ducks from native‐grass seeding practices of CRP were similar to those of tame‐grass seeding practices. Although there may be other reasons to plant native seed mixes when establishing CRP tracts (e.g., native pollinators or insects, other wildlife species, etc.), our study suggests that duck nesting density and nest survival are not among those reasons.

North Dakota, South Dakota↗
USGS2018

Critically assessing the utility of portable lead analyzers for wildlife conservation

Lead (Pb) exposure in wildlife is a widespread management and conservation concern. Quantitative determination of Pb concentrations in wildlife tissues is the foundation for estimating exposure and risk. Development of low‐cost, portable instruments has improved access and cost‐effectiveness of determining Pb concentrations in blood samples, while also facilitating the ability for wildlife researchers to conduct near real‐time Pb testing. However, these instruments, which use anodic stripping voltammetry (ASV) methodology, may produce an analytical bias in wildlife‐blood Pb concentrations. Additionally, their simplicity invites use without appropriate quality‐assurance–quality‐control measures. Together, these factors can reduce data quality and hamper the ability to evaluate it, raising concerns about use of these instruments to inform important conservation issues. We document the extent to which this bias is addressed in the wildlife toxicology literature, develop quantitative approaches for correcting the bias, and provide recommendations to ensure robust data quality when using these instruments. Of the 25 studies we reviewed that referenced ASV use for determining Pb exposure in wildlife, only 32% acknowledged the existence of bias from the instrument. Importantly, another 20% of the studies actually reported ASV and spectroscopic‐based results together without acknowledging their lack of equivalence. Using a multispecies data set of avian blood Pb concentrations, we found that ASV‐based estimates of paired blood Pb concentrations were 30–38% lower than those from standard spectrometric‐based methods. We provide regression equations based on this analysis of 453 blood samples to allow users of ASV instruments to adjust Pb concentrations to spectrometric‐equivalent values, and propose a series of guidelines to follow when using these instruments to improve data validity.

Wildlife Society Bulletin↗
USGS2002

Bet-hedging applications for conservation

One of the early tenets of conservation biology is that population viability is enhanced by maintaining multiple populations of a species. The strength of this tenet is justified by principles of bet-hedging. Management strategies that reduce variance in population size will also reduce risk of extinction. Asynchrony in population fluctuations in independent populations reduces variance in the aggregate of populations whereas environmental correlation among areas increases the risk that all populations will go extinct. We review the theoretical rationale of bet-hedging and suggest applications for conservation management of least terns in Nebraska and grizzly bears in the northern Rocky Mountains of the United States. The risk of extinction for least terns will be reduced if we can sustain the small central Platte River population in addition to the larger population on the lower Platte. Similarly, by restoring grizzly bears to the Bitterroot wilderness of Idaho and Montana can reduce the probability of extinction for grizzly bears in the Rocky Mountains of the United States by as much as 69-93%.

Journal of Biosciences↗
USGS2012

The Adaptation for Conservation Targets (ACT) Framework: A tool for incorporating climate change into natural resource management

As natural resource management agencies and conservation organizations seek guidance on responding to climate change, myriad potential actions and strategies have been proposed for increasing the long-term viability of some attributes of natural systems. Managers need practical tools for selecting among these actions and strategies to develop a tailored management approach for specific targets at a given location. We developed and present one such tool, the participatory Adaptation for Conservation Targets (ACT) framework, which considers the effects of climate change in the development of management actions for particular species, ecosystems and ecological functions. Our framework is based on the premise that effective adaptation of management to climate change can rely on local knowledge of an ecosystem and does not necessarily require detailed projections of climate change or its effects. We illustrate the ACT framework by applying it to an ecological function in the Greater Yellowstone Ecosystem (Montana, Wyoming, and Idaho, USA)—water flows in the upper Yellowstone River. We suggest that the ACT framework is a practical tool for initiating adaptation planning, and for generating and communicating specific management interventions given an increasingly altered, yet uncertain, climate.

Environmental Management↗
USGS2018

Willingness to pay for conservation of transborder migratory species: A case study of the Mexican free-tailed bat in the United States and Mexico

We estimated U.S. and Mexican citizens’ willingness to pay (WTP) for protecting habitat for a transborder migratory species, the Mexican free-tailed bat ( Tadarida brasiliensis mexicana ), using the contingent valuation method. Few contingent valuation surveys have evaluated whether households in one country would pay to protect habitat in another country. This study addresses that gap. In our study, Mexican respondents were asked about their WTP for conservation of Mexican free-tailed bat habitat in Mexico and in the United States. Similarly, U.S. respondents were asked about their WTP for conservation in the United States and in Mexico. U.S. households would pay $ 30 annually to protect habitat in the United States and $ 24 annually to protect habitat in Mexico. Mexican households would pay $8 annually to protect habitat in Mexico and $ 5 annually to protect habitat in the United States. In both countries, these WTP amounts rose significantly for increasing the size of the bat population rather than simply stabilizing the current bat population. The ratio of Mexican household WTP relative to U.S. household WTP is nearly identical to that of Mexican household income relative to U.S. household income. This suggests that the perceived economic benefits received from the bats is similar in Mexico and the United States, and that scaling WTP by relative income in international benefit transfer may be plausible.

Environmental Management↗
USGS2016

Cryptic invasion of Northern Leopard Frogs ( Rana pipiens ) across phylogeographic boundaries and a dilemma for conservation of a declining amphibian

Anthropogenic introduction of species is a major contributor to loss of biodiversity. Translocations within the range of a species are less frequently recognized, but have the potential for negative effects as well. Genetic mixing may lead to loss of local adaptations or further decline through outbreeding depression. These cryptic invasions may be quite difficult to recognize, but genetic tools can be used to recognize and monitor such intraspecific introductions. Conversely, translocations within species can be an important conservation tool to reduce inbreeding depression and replace lost genetic diversity. Thus, cryptic invasions can be either an aid or a hindrance to conservation efforts. We tested for the presence of non-native genotypes and assessed the extent and nature of introgression in populations of Northern Leopard Frog ( Rana pipiens ) in the southwestern US, where populations have declined to a few remnant populations. The most abundant and diverse complex of populations in the region contained a mitochondrial haplotype that was not native to the western US, probably resulting from the introduction of released pets, laboratory animals, or release during fish stocking. These non-native haplotypes were well integrated into a large complex of ponds and lakes, contributing to high genetic diversity in this area. Logistically, the geographic extent of non-native genetic influence within this population precludes eliminating or controlling the non-native component of this population. We recommend assessing the progress and fate of the introgression over time—along with population fitness parameters—to determine whether this introduction is beneficial or detrimental to population persistence. Meanwhile, translocations from nearby locations with similar environmental conditions have the best prospects for avoiding problems with outbreeding depression in other declining populations and will also most effectively preserve regional genetic diversity.

Biological Invasions↗
USGS2021

Prioritizing landscapes for grassland bird conservation with hierarchical community models

Context Given widespread population declines of birds breeding in North American grasslands, management that sustains wildlife while supporting rancher livelihoods is needed. However, management effects vary across landscapes, and identifying areas with the greatest potential bird response to conservation is a pressing research need. Objectives We developed a hierarchical modeling approach to study grassland bird response to habitat factors at multiple scales and levels. We then identified areas to prioritize for implementing a bird-friendly ranching program. Methods Using bird survey data from grassland passerine species and 175 sites (2009–2018) across northeast Wyoming, USA, we fit hierarchical community distance sampling models and evaluated drivers of site-level density and regional-level distribution. We then created spatially-explicit predictions of bird density and distribution for the study area and predicted outcomes from pasture-scale management scenarios. Results Cumulative overlap of species distributions revealed areas with greater potential community response to management. Within each species’ potential regional-level distribution, the grassland bird community generally responded negatively to cropland cover and vegetation productivity at local scales (up to 10 km of survey sites). Multiple species declined with increasing bare ground and litter cover, shrub cover, and grass height measured within sites. Conclusions We demonstrated a novel approach to multi-scale and multi-level prioritization for grassland bird conservation based on hierarchical community models and extensive population monitoring. Pasture-scale management scenarios also suggested the examined community may benefit from less bare ground cover and shorter grass height. Our approach could be extended to other bird guilds in this region and beyond.

Wyoming↗
USGS2011

Integrating scales of seagrass monitoring to meet conservation needs

We evaluated a hierarchical framework for seagrass monitoring in two estuaries in the northeastern USA: Little Pleasant Bay, Massachusetts, and Great South Bay/Moriches Bay, New York. This approach includes three tiers of monitoring that are integrated across spatial scales and sampling intensities. We identified monitoring attributes for determining attainment of conservation objectives to protect seagrass ecosystems from estuarine nutrient enrichment. Existing mapping programs provided large-scale information on seagrass distribution and bed sizes (tier 1 monitoring). We supplemented this with bay-wide, quadrat-based assessments of seagrass percent cover and canopy height at permanent sampling stations following a spatially distributed random design (tier 2 monitoring). Resampling simulations showed that four observations per station were sufficient to minimize bias in estimating mean percent cover on a bay-wide scale, and sample sizes of 55 stations in a 624-ha system and 198 stations in a 9,220-ha system were sufficient to detect absolute temporal increases in seagrass abundance from 25% to 49% cover and from 4% to 12% cover, respectively. We made high-resolution measurements of seagrass condition (percent cover, canopy height, total and reproductive shoot density, biomass, and seagrass depth limit) at a representative index site in each system (tier 3 monitoring). Tier 3 data helped explain system-wide changes. Our results suggest tiered monitoring as an efficient and feasible way to detect and predict changes in seagrass systems relative to multi-scale conservation objectives.

Massachusetts↗
USGS2016

Clinal patterns in genetic variation for northern leopard frog ( Rana pipiens ): Conservation status and population histories

The security of the northern leopard frog ( Rana pipiens) varies spatially with populations east and west of North Dakota considered as secure and at risk, respectively. We used genetic markers to characterize the conservation status of northern leopard frog populations across North Dakota. We used multiple regression analyses and model selection to evaluate correlations of expected heterozygosity ( H E ) with the direct and additive effects of: i ) geographic location, ii ) wetland density and iii ) average annual precipitation . There was lower genetic diversity in the western portion of the state due to lower levels of diversity for populations southwest of the Missouri River. This may reflect a refugial/colonization signature for the only non-glaciated area of North Dakota. Genetic diversity was also positively associated with wetland densities which is consistent with the reliance of this species on a mosaic of wetlands. Our findings suggest that populations in the southwestern part of North Dakota are of higher conservation concern, a finding consistent with the higher risk noted for northern leopard frog populations in most states west of North Dakota. Our findings also pose the hypothesis that climate change induced changes in wetland densities will reduce genetic diversity of northern leopard frog populations.

North Dakota↗
USGS2021

Wetland conservation: Challenges related to water law and farm policy

Water is essential for wetland function and sustaining migratory networks for wetland wildlife across broad landscapes. Groundwater declines and surface flow reductions that impact aquatic and wetland organisms are common in the western U.S. and increasingly in the eastern U.S. Agriculture is the largest consumptive water user in the U.S. and understanding economic incentives of water-use practices and the legal context of water rights is foundational to identifying meaningful water solutions. In this paper, we provide a brief legal overview of water rights in the U.S. and synthesize the literature to provide a broad overview of how federal farm policy influences water-use decisions. We conclude that the ultimate cause of many water-use conflicts is an inefficient, farm economy that is driven by several proximate factors, of which outdated water laws and subsidies that encourage increased water use are among the most important. Development of multi-scale water budgets to assess project impacts and by working more intensively at local watershed and aquifer scales can improve conservation efforts. Finally, detailed analyses to understand and minimize the impacts of specific federal policies on agricultural water use would enhance water conservation efforts, facilitate long-term food and water security, and provide greater protection for wetland and aquatic resources.

Wetlands↗
USGS2024

Joint spatial modeling bridges the gap between disparate disease surveillance and population monitoring efforts informing conservation of at-risk bat species

White-Nose Syndrome (WNS) is a wildlife disease that has decimated hibernating bats since its introduction in North America in 2006. As the disease spreads westward, assessing the potentially differential impact of the disease on western bat species is an urgent conservation need. The statistical challenge is that the disease surveillance and species response monitoring data are not co-located, available at different spatial resolutions, non-Gaussian, and subject to observation error requiring a novel extension to spatially misaligned regression models for analysis. Previous work motivated by epidemiology applications has proposed two-step approaches that overcome the spatial misalignment while intentionally preventing the human health outcome from informing estimation of exposure. In our application, the impacted animals contribute to spreading the fungus that causes WNS, motivating development of a joint framework that exploits the known biological relationship. We introduce a Bayesian, joint spatial modeling framework that provides inferences about the impact of WNS on measures of relative bat activity and accounts for the uncertainty in estimation of WNS presence at non-surveyed locations. Our simulations demonstrate that the joint model produced more precise estimates of disease occurrence and unbiased estimates of the association between disease presence and the count response relative to competing two-step approaches. Our statistical framework provides a solution that leverages disparate monitoring activities and informs species conservation across large landscapes. Stan code and documentation are provided to facilitate access and adaptation for other wildlife disease applications.

Journal of Agricultural, Biological and Environmen↗
USGS2026

Tidal forested wetlands can be incorporated into blue carbon conservation and restoration strategies

Purpose of Review Blue carbon is an important concept for environmental policy. Blue carbon strategies (conservation and restoration for carbon gain) have been primarily implemented with mangroves, though are likely to be suitable for other tidal forested wetlands. Here, we discuss the expanding definition of blue carbon encompassing all tidal forested wetlands, synthesize ecological and carbon sink knowledge of tidal forested wetlands, and reflect on key actions in mangrove blue carbon research and implementation that could be applied to other tidal forested wetlands. Recent Findings Conceptually, the blue carbon concept has now expanded beyond traditional coastal vegetated ecosystems to include all tidal wetlands, including tidal forested wetlands. Emerging data on carbon sequestration, emissions, and budgets from around the world now show that many tidal forested wetland ecosystems are carbon sinks at a magnitude similar to mangroves. At the global scale, mangroves have become incorporated into blue carbon strategies rapidly compared to other tidal forested wetlands, facilitated by agenda-setting papers, adequate data addressing concerns on emissions and permanence, the availability of global maps, a clear ecosystem definition, clear accounting and policy frameworks, and international stakeholders who acted as high profile ecosystem advocates, alongside long-term capacity building efforts. This provides a roadmap for implementation in other tidal forested wetlands. Summary Tidal forested wetlands other than mangroves have high potential for blue carbon management. Many tidal forested wetlands share biophysical similarities with mangroves, carbon stocks can be similar, and methane emissions are often no higher. An increasing evidence base, challenging assumptions around greenhouse gas fluxes, and robust engagement with policy actors and frameworks, could increase the use of blue carbon for tidal forested wetland conservation and restoration.

Current Forestry Reports↗
USGS2015

Sea otters in captivity: applications and implications of husbandry development, public display, scientific research and management, and rescue and rehabilitation for sea otter conservation

Studies of sea otters in captivity began in 1932, producing important insights for conservation. Soviet (initiated in 1932) and United States (1951) studies provided information on captive otter husbandry, setting the stage for eventual large-scale translocations as tools for population restoration. Early studies also informed effective housing of animals in zoos and aquaria, with sea otters first publicly displayed in 1954. Surveys credited displayed otters in convincing the public of conservation values. After early studies, initial scientific data for captive sea otters in aquaria came from work initiated in 1956, and from dedicated research facilities beginning in 1968. Significant achievements have been made in studies of behavior, physiology, reproduction, and high-priority management issues. Larger-scale projects involving translocation and oil spill response provided extensive insights into stress reactions, water quality issues in captivity, and effects of oil spills.

Book chapter↗
USGS2015

Synopsis of the history of sea otter conservation in the United States

In the late 1860s, declining US sea otter populations elicited concern because of prior excessive harvests. Congress mandated protection of Alaskan sea otters in 1868, but hunting continued unrestrained. The Fur Seal Treaty of 1911 (abrogated in 1941) protected sea otters in international waters, but was not applicable to most sea otter habitats and failed to terminate all legal sea otter harvests. Between 1941 and 1972 only the State of California was consistently engaged in sea otter conservation, based on a 1913 state law. Trends in cultural values toward protection of species based on imperiled status rather than economics led to the Marine Mammal Protection Act (1972), giving sea otters unambiguous protection in all US territorial waters. Sea otter habitat protection by the US government began in the 1890s. State marine protected areas potentially support sea otter conservation, particularly when paired with adjacent federal protected entities in or near sea otter habitat.

Book chapter↗