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At least 649 records · Page 36Linked to original sources

USGS2022

Influence of offshore oil and gas structures on seascape ecological connectivity

Offshore platforms, subsea pipelines, wells and related fixed structures supporting the oil and gas (O&G) industry are prevalent in oceans across the globe, with many approaching the end of their operational life and requiring decommissioning. Although structures can possess high ecological diversity and productivity, information on how they interact with broader ecological processes remains unclear. Here, we review the current state of knowledge on the role of O&G infrastructure in maintaining, altering or enhancing ecological connectivity with natural marine habitats. There is a paucity of studies on the subject with only 33 papers specifically targeting connectivity and O&G structures, although other studies provide important related information. Evidence for O&G structures facilitating vertical and horizontal seascape connectivity exists for larvae and mobile adult invertebrates, fish and megafauna; including threatened and commercially important species. The degree to which these structures represent a beneficial or detrimental net impact remains unclear, is complex and ultimately needs more research to determine the extent to which natural connectivity networks are conserved, enhanced or disrupted. We discuss the potential impacts of different decommissioning approaches on seascape connectivity and identify, through expert elicitation, critical knowledge gaps that, if addressed, may further inform decision making for the life cycle of O&G infrastructure, with relevance for other industries (e.g. renewables). The most highly ranked critical knowledge gap was a need to understand how O&G structures modify and influence the movement patterns of mobile species and dispersal stages of sessile marine species. Understanding how different decommissioning options affect species survival and movement was also highly ranked, as was understanding the extent to which O&G structures contribute to extending species distributions by providing rest stops, foraging habitat, and stepping stones. These questions could be addressed with further dedicated studies of animal movement in relation to structures using telemetry, molecular techniques and movement models. Our review and these priority questions provide a roadmap for advancing research needed to support evidence-based decision making for decommissioning O&G infrastructure.

Global Change Biology↗

USGS2010

Modeling the human invader in the United States

Modern biogeographers recognize that humans are seen as constituents of ecosystems, drivers of significant change, and perhaps, the most invasive species on earth. We found it instructive to model humans as invasive organisms with the same environmental factors. We present a preliminary model of the spread of modern humans in the conterminous United States between 1992 and 2001 based on a subset of National Land Cover Data (NLCD), a time series LANDSAT product. We relied on the commonly used Maxent model, a species-environmental matching model, to map urbanization. Results: Urban areas represented 5.1% of the lower 48 states in 2001, an increase of 7.5% (18,112 km 2 ) in the nine year period. At this rate, an area the size of Massachusetts is converted to urban land use every ten years. We used accepted models commonly used for mapping plant and animal distributions and found that climatic and environmental factors can strongly predict our spread (i.e., the conversion of forests, shrub/grass, and wetland areas into urban areas), with a 92.5% success rate (Area Under the Curve). Adding a roads layer in the model improved predictions to a 95.5% success rate. 8.8% of the 1-km 2 > cells in the conterminous U.S. now have a major road in them. In 2001, 0.8% of 1-km 2 > cells in the U.S. had an urbanness value of > 800, (>89% of a 1-km 2 > cell is urban), while we predict that 24.5% of 1-km 2 > cells in the conterminous U.S. will be > 800 eventually. Main conclusion: Humans have a highly predictable pattern of urbanization based on climatic and topographic variables. Conservation strategies may benefit from that predictability.

Journal of Applied Remote Sensing↗

USGS2006

Educating veterinarians for careers in free-ranging wildlife medicine and ecosystem health

In the last 10 years, the field of zoological medicine has seen an expansive broadening into the arenas of free-ranging wildlife, conservation medicine, and ecosystem health. During the spring/summer of 2005, we prepared and disseminated a survey designed to identify training and educational needs for individuals entering the wildlife medicine and ecosystem health fields. Our data revealed that few wildlife veterinarians believe that the training they received in veterinary school adequately prepared them to acquire and succeed in their field. Wildlife veterinarians and their employers ranked mentorship with an experienced wildlife veterinarian, training in leadership and communication, courses and externships in wildlife health, and additional formal training beyond the veterinary degree as important in preparation for success. Employers, wildlife veterinarians, and job seekers alike reported that understanding and maintaining ecosystem health is a key component of the wildlife veterinarian's job description, as it is critical to protecting animal health, including human health. Today's wildlife veterinarians are a new type of transdisciplinary professional; they practice medicine in their communities and hold titles in every level of government and academia. It is time that we integrate ecosystem health into our curricula to nurture and enhance an expansive way of looking at veterinary medicine and to ensure that veterinary graduates are prepared to excel in this new and complex world, in which the health of wildlife, domestic animals, and people are interdependent.

Journal of Veterinary Medical Education↗

USGS2018

Marine threats overlap key foraging habitat for two imperiled sea turtle species in the Gulf of Mexico

Effective management of human activities affecting listed species requires understanding both threats and animal habitat-use patterns. However, the extent of spatial overlap between high-use foraging areas (where multiple marine species congregate) and anthropogenic threats is not well known. Our modeling approach incorporates data on sea turtle spatial ecology and a suite of threats in the Gulf of Mexico to identify and map “hot spots” of threats to two imperiled turtle species. Of all 820 “high” threats grid cells, our tracked turtles foraged at least one day in 77% of them. Although threat data were not available outside the U.S. Exclusive Economic Zone, our map of turtle and threat “hotspots” can be incorporated in future more comprehensive threat analyses for the region. Knowledge of these shared foraging- and threat-areas can assist managers charged with designing effective conservation and population recovery strategies, in future habitat modeling efforts, and in designations of Gulf of Mexico habitat with high conservation value.

Frontiers in Marine Science↗

USGS2018

Biological connectivity of seasonally ponded wetlands across spatial and temporal scales

Many species that inhabit seasonally ponded wetlands also rely on surrounding upland habitats and nearby aquatic ecosystems for resources to support life stages and to maintain viable populations. Understanding biological connectivity among these habitats is critical to ensure that landscapes are protected at appropriate scales to conserve species and ecosystem function. Biological connectivity occurs across a range of spatial and temporal scales. For example, at annual time scales many organisms move between seasonal wetlands and adjacent terrestrial habitats as they undergo life‐stage transitions; at generational time scales, individuals may disperse among nearby wetlands; and at multigenerational scales, there can be gene flow across large portions of a species’ range. The scale of biological connectivity may also vary among species. Larger bodied or more vagile species can connect a matrix of seasonally ponded wetlands, streams, lakes, and surrounding terrestrial habitats on a seasonal or annual basis. Measuring biological connectivity at different spatial and temporal scales remains a challenge. Here we review environmental and biological factors that drive biological connectivity, discuss implications of biological connectivity for animal populations and ecosystem processes, and provide examples illustrating the range of spatial and temporal scales across which biological connectivity occurs in seasonal wetlands.

Journal of the American Water Resources Associatio↗

USGS2023

Influence of lamprey rearing type on measures of performance

Declines in populations of Pacific Lamprey (Entosphenus tridentatus) have raised concerns by the Columbia River tribes, who then initiated efforts to protect and restore them throughout their historical range. The Columbia River Inter-Tribal Fish Commission (CRITFC) devised a restoration plan for lamprey in the Columbia River Basin which highlights the significance of lamprey to the tribes and recommends conservation actions. The plan calls for the development of artificial propagation (AP) protocols to provide fish for research (e.g., downstream passage studies) and restoration activities (e.g., supplemental releases into streams/rivers). The ideal outcome of these efforts would be cultured fish that are comparable to the corresponding wild fish, and efforts are underway to conduct such evaluations in larval and juvenile lamprey. The CRITFC lamprey restoration plan lists improving dam passage for juvenile and larval lamprey as a high priority action. Active telemetry techniques have not been an option until recently, when a prototype micro acoustic transmitter was designed for small, elongate fishes like lamprey and eels. Passage survival studies of juvenile and larval lamprey using acoustic telemetry are now possible but are challenged with the limited availability of research animals. The use of AP fish would facilitate passage survival studies, under the assumption that AP juvenile and larval lamprey perform and survive comparably to the wild lamprey they are intended to represent. The current study was enacted to add to the growing knowledge of how reliably AP lamprey can be used as surrogates for wild lamprey. Study objectives were to: 1) compare the swimming ability of AP and wild juvenile lamprey implanted with the prototype micro acoustic transmitter and 2) compare the performance of AP and wild larval lamprey by evaluating night activity levels, burrowing ability, and photokinetic response to tail illumination over a period of 5-months in a culture setting. Evaluations of juvenile lamprey sustained swimming performance did not reveal any differences between tagged and untagged lamprey of AP or wild origin. We standardized the stage of transformation for all tested lamprey to minimize variation. Our tests were constrained by limited access to juvenile lamprey, so significant differences between rearing types may have gone undetected. More information on how rearing type influences other lamprey life stages and swimming performance will add to the growing knowledge on how reliably AP lamprey can serve as surrogates for wild lamprey. We compared AP and wild larval lamprey using three performance metrics, both shortly after they arrived at our laboratory and through a 5-month study period. Within the AP and wild test groups, we divided lamprey into small (30-70 mm total length) and large (80-120 mm total length) size categories, forming four test groups. Each of the test groups were comprised of 25 lamprey and were held in separate tanks. These tanks were the source of test fish for all performance testing. Our results for 2 of 3 of the performance metrics showed no differences between rearing types, and we found limited evidence to suggest that duration in a culture setting changed performance. Night activity levels were low for all test groups. Burrowing times were significantly different by rearing type, with wild lamprey burrowing faster than AP lamprey, in both the small and large size categories. These significant differences in rearing type could be a concern for use of AP lamprey for restoration or research needs, but they may not be biologically meaningful. Both AP and wild lamprey completed burrowing in median times of less than 1 min, which minimizes concerns about predation risk. Additional opportunities to evaluate burrowing performance of AP and wild larval lamprey would be helpful to inform future planned uses of AP lamprey. Finally, our evaluations of photokinetic response to tail illumination revealed similar proportions of AP and wild larvae moving in response to illumination, and no significant differences in response time between the groups. The wild lamprey, however, consistently had faster (but not significantly) response times than AP fish. This finding supports the significantly faster burrowing times we observed for wild lamprey compared to AP fish. Taken together, these lines of evidence raise some concerns for the ability of AP lamprey to serve as defensible surrogates for wild lamprey because the ability to reliably burrow is so critical for larvae. Burrowing performance and photokinetic response to tail illumination were both easy to measure and will be valuable metrics for evaluating rearing types in future studies.

Report↗

USGS2018

Concentrations of environmental DNA (eDNA) reflect spawning salmon abundance at fine spatial and temporal scales

Developing fast, cost-effective assessments of wild animal abundance is an important goal for many researchers, and environmental DNA (eDNA) holds much promise for this purpose. However, the quantitative relationship between species abundance and the amount of DNA present in the environment is likely to vary substantially among taxa and with ecological context. Here, we report a strong quantitative relationship between eDNA concentration and the abundance of spawning sockeye salmon in a small stream in Alaska, USA, where we took temporally- and spatially-replicated samples during the spawning period. This high-resolution dataset suggests that (1) eDNA concentrations vary significantly day-to-day, and likely within hours, in the context of the dynamic biological event of a salmon spawning season; (2) eDNA, as detected by species-specific quantitative PCR probes, seems to be conserved over short distances (tens of meters) in running water, but degrade quickly over larger scales (ca. 1.5 km); and (3) factors other than the mere presence of live, individual fish — such as location within the stream, live/dead ratio, and water temperature — can affect the eDNA-biomass correlation in space or time. A multivariate model incorporating both biotic and abiotic variables accounted for over 75% of the eDNA variance observed, suggesting that where a system is well-characterized, it may be possible to predict species' abundance from eDNA surveys, although we underscore that species- and system-specific variables are likely to limit the generality of any given quantitative model. Nevertheless, these findings provide an important step toward quantitative applications of eDNA in conservation and management.

Alaska↗

USGS2012

The genetic structure of a relict population of wood frogs

Habitat fragmentation and the associated reduction in connectivity between habitat patches are commonly cited causes of genetic differentiation and reduced genetic variation in animal populations. We used eight microsatellite markers to investigate genetic structure and levels of genetic diversity in a relict population of wood frogs ( Lithobates sylvatica ) in Rocky Mountain National Park, Colorado, where recent disturbances have altered hydrologic processes and fragmented amphibian habitat. We also estimated migration rates among subpopulations, tested for a pattern of isolation-by-distance, and looked for evidence of a recent population bottleneck. The results from the clustering algorithm in Program STRUCTURE indicated the population is partitioned into two genetic clusters (subpopulations), and this result was further supported by factorial component analysis. In addition, an estimate of FST (FST = 0.0675, P value \0.0001) supported the genetic differentiation of the two clusters. Estimates of migration rates among the two subpopulations were low, as were estimates of genetic variability. Conservation of the population of wood frogs may be improved by increasing the spatial distribution of the population and improving gene flow between the subpopulations. Construction or restoration of wetlands in the landscape between the clusters has the potential to address each of these objectives.

Colorado↗

USGS2000

Sea otters past and present perspectives

Sea otters have been an important resource for people living along the North Pacific coast for thousands of years. At least two aspects of the sea otters' natural history have linked them with humans: their pelt and their food habits. Sea otter pelts, arguably the finest in the animal kingdom, were fashioned into garments, particularly in northern latitudes, while the presence of sea otters influenced the availability of some marine invertebrates, like snails, clams and abalone, that provided food for coastal people. In addition, sea otters spurred a growing fur trade after Vitus Bering's explorations of the North Pacific in the early 1700s revealed their widespread abundance. This commercial harvest was instrumental in European exploration and settlement of the Pacific Rim and led to the near-extermination of the sea otter, Enhydra lutris, in following centuries. Largely because of their life history and their direct relations with coastal residents, sea otters are a comparatively well-understood marine mammal. During the past few decades, concern for sea otters has broadened to encompass an interest in global resource conservation and restoration, as well as community ecology. This more recent focus on sea otters now extends to humans far removed from marine environments. Early sea otters evolved about 12 million years ago from Eurasian and African ancestors. They reached the North Pacific by way of two proposed migration paths, one along the Bering Land Bridge between northeastern Asia and northwestern North America and a second from the Atlantic Ocean that entered the Pacific through a channel in the central Americas. Modern sea otters occur only in the North Pacific and have occupied their current range for the past 1 million to 3 million years.

Alaska Geographic↗

USGS2006

Evidence for the role of infectious disease in species extinction and endangerment

Infectious disease is listed among the top five causes of global species extinctions. However, the majority of available data supporting this contention is largely anecdotal. We used the IUCN Red List of Threatened and Endangered Species and literature indexed in the ISI Web of Science to assess the role of infectious disease in global species loss. Infectious disease was listed as a contributing factor in <4% of species extinctions known to have occurred since 1500 (833 plants and animals) and as contributing to a species' status as critically endangered in <8% of cases (2852 critically endangered plants and animals). Although infectious diseases appear to play a minor role in global species loss, our findings underscore two important limitations in the available evidence: uncertainty surrounding the threats to species survival and a temporal bias in the data. Several initiatives could help overcome these obstacles, including rigorous scientific tests to determine which infectious diseases present a significant threat at the species level, recognition of the limitations associated with the lack of baseline data for the role of infectious disease in species extinctions, combining data with theory to discern the circumstances under which infectious disease is most likely to serve as an agent of extinction, and improving surveillance programs for the detection of infectious disease. An evidence-based understanding of the role of infectious disease in species extinction and endangerment will help prioritize conservation initiatives and protect global biodiversity.

Conservation Biology↗

USGS2021

Historic population estimates for bottlenose dolphins (Tursiops truncatus) in Aragua, Venezuela indicate monitoring need

This study reports historic capture-mark-recapture survival and abundance estimates of common bottlenose dolphins ( Tursiops truncatus ) based on photo-identification surveys of coastal Venezuela (along the Aragua coast between Turiamo Bay and Puerto Colombia). We used the most recent data available: dolphins identified by unique dorsal fin marks during wet and dry season surveys conducted from 2004 to 2008. Dolphin encounter histories were analyzed in the Closed Capture Robust Design framework, with the top model including random movement, constant survival, and capture-recapture probabilities that varied by secondary periods. Survival of marked adults was estimated at 0.99 (95% CI = 0.97 to 1.00). Population estimates for all adults (marked and unmarked) averaged 31 animals (SD = 13.8), and for all dolphins (all adults and calves), 41 animals (SD = 17.2). Coastal bottlenose dolphins face numerous threats, including ship strikes, oil spills, conflict with recreational and industrial fisheries, other negative human interactions, biotoxins, chemicals, noise, freshwater discharge, and coastal development. Further, small populations are, in general, at increased risk due to reduced resiliency and recovery potential when exposed to such threats and to expected environmental and demographic stochasticity. These historic estimates of abundance and survival are critical for establishing a reference state and indicate a need for ongoing monitoring of the small dolphin population while the Aragua coast is still, as of yet, relatively little impacted by humans. Should coastal development increase (as is the global trend) and/or environmental catastrophes (e.g., harmful algal blooms, hurricanes, and oil spills) occur, these historic estimates will be essential for assessing impacts and guiding management and conservation interventions. Our results show year-round dolphin presence and highlight the Venezuelan coastal–oceanic landscape as an area of both future research and conservation importance.

Aragua↗

USGS2023

Evidence of population-level impacts and resiliency for Gulf of Mexico shelf taxa following the Deepwater Horizon oil spill

The goal of this paper was to review the evidence of population-level impacts of the Deepwater Horizon Oil Spill (DWH) on Gulf of Mexico (GOM) continental shelf taxa, as well as evidence of resiliency following the DWH. There is considerable environmental and biological evidence that GOM shelf taxa were exposed to and suffered direct and indirect impacts of the DWH. Numerous assessments, from mesocosm studies to analysis of biopsied tissue or tissue samples from necropsied animals, revealed a constellation of physiological effects related to DWH impacts on GOM biota, some of which clearly or likely resulted in mortality. While the estimated concentrations of hydrocarbons in shelf waters and sediments were orders of magnitude lower than measured in inshore or deep GOM environments, the level of mortality observed or predicted was substantial for many shelf taxa. In some cases, such as for zooplankton, community shifts following the spill were ephemeral, likely reflecting high rates of population turnover and productivity. In other taxa, such as GOM reef fishes, impacts of the spill are confounded with other stressors, such as fishing mortality or the appearance and rapid population growth of invasive lionfish ( Pterois spp.). In yet others, such as cetaceans, modeling efforts to predict population-level effects of the DWH made conservative assumptions given the species’ protected status, which post-DWH population assessments either failed to detect or population increases were estimated. A persistent theme that emerged was the lack of precise population-level data or assessments prior to the DWH for many taxa, but even when data or assessments did exist, examining evidence of population resiliency was confounded by other stressors impacting GOM biota. Unless efforts are made to increase the resolution of the data or precision of population assessments, difficulties will likely remain in estimating the scale of population-level effects or resiliency in the case of future large-scale environmental catastrophes.

Gulf of Mexico↗

USGS2019

A novel picorna-like virus in a Wabash Pigtoe (Fusconaia flava) from the upper Mississippi River, USA

Unionid mussels are threatened by multiple environmental stressors and have experienced mass mortality events over the last several decades, but the role of infectious disease in unionid health and population declines remains poorly understood. Although several microbial agents have been found in unionids, to date only one virus has been documented—Lea plague virus ( Arenaviridae ) in propagated Triangle Shell mussels ( Hyriopsis cumingii ) in China. We used next-generation DNA sequencing to screen hemolymph of seven individuals of five unionid species from the Upper Mississippi River basin, USA for viruses. We identified the complete polyprotein gene of a novel picornalike virus in one individual of the Wabash Pigtoe ( Fusconaia flava ). The virus is a member of the Nora virus clade of picornalike viruses and is most closely related to viruses from arthropods in China. We did not detect viruses in another Wabash Pigtoe or in animals of the other four species. It is premature to make inferences about the role of this virus in the health of Wabash Pigtoes or other unionid species or the origin or transmission of this virus. Nevertheless, to our knowledge, our results represent the first report of a virus in wild North American unionids. Technologies based on next-generation DNA sequencing should prove useful for identifying new viruses and investigating their role in unionid health and disease.

Minnesota, Wisconsin↗

USGS2009

Effects of Water-Management Strategies on Water Resources in the Pawcatuck River Basin, Southwestern Rhode Island and Southeastern Connecticut

The Pawcatuck River Basin in southwestern Rhode Island and southeastern Connecticut is an important high-quality water resource for domestic and public supplies, irrigation, recreation, and the aquatic ecosystem. Concerns about the effects of water withdrawals on aquatic habitat in the basin have prompted local, State, and Federal agencies to explore water-management strategies that minimize the effects of withdrawals on the aquatic habitat. As part of this process, the U.S. Geological Survey in cooperation with the U.S. Department of Agriculture Natural Resources Conservation Service and the Rhode Island Water Resources Board completed a study to assess the effects of current (2000-04) and potential water withdrawals on streamflows and groundwater levels using hydrologic simulation models developed for the basin. The major findings of the model simulations are: *Moving highly variable seasonal irrigation withdrawals from streams to groundwater wells away from streams reduces short-term fluctuations in streamflow and increases streamflow in the summer when flows are lowest. This occurs because of the inherent time lag between when water is withdrawn from the aquifer and when it affects streamflow. *A pumped well in the vicinity of small streams indicates that if withdrawals exceed available streamflow, groundwater levels drop substantially as a consequence of water lost from aquifer storage, which may reduce the time wetlands and vernal pools are saturated, affecting the animal and plant life that depend on these habitats. *The effects of pumping on water resources such as ponds, streams, and wetlands can be minimized by relocating pumping wells, implementing seasonal pumping schemes that utilize different wells and pumping rates, or both. *The effects of projected land-use change, mostly from forest to low- and medium density housing, indicate only minor changes in streamflow at the subbasin scale examined; however, at a local scale, high flows could increase, and low flows could decrease as a result of increased impervious area. In some instances, low flows could increase slightly as a result of decreased evapotranspiration from the loss of deeprooted vegetation (forest) associated with development. *In some subbasins where large areas of agricultural lands were converted to low- and medium-density housing, low flows increase because the consumptive domestic water use was projected to be less than consumptive agricultural water use. All agricultural water use was for irrigation purposes and was assumed to be lost from the basin through evapotranspiration.

Circular↗

USGS2010

Modeling spatial variation in avian survival and residency probabilities

The importance of understanding spatial variation in processes driving animal population dynamics is widely recognized. Yet little attention has been paid to spatial modeling of vital rates. Here we describe a hierarchical spatial autoregressive model to provide spatially explicit year-specific estimates of apparent survival (phi) and residency (pi) probabilities from capture-recapture data. We apply the model to data collected on a declining bird species, Wood Thrush (Hylocichla mustelina), as part of a broad-scale bird-banding network, the Monitoring Avian Productivity and Survivorship (MAPS) program. The Wood Thrush analysis showed variability in both phi and pi among years and across space. Spatial heterogeneity in residency probability was particularly striking, suggesting the importance of understanding the role of transients in local populations. We found broad-scale spatial patterning in Wood Thrush phi and pi that lend insight into population trends and can direct conservation and research. The spatial model developed here represents a significant advance over approaches to investigating spatial pattern in vital rates that aggregate data at coarse spatial scales and do not explicitly incorporate spatial information in the model. Further development and application of hierarchical capture-recapture models offers the opportunity to more fully investigate spatiotemporal variation in the processes that drive population changes.

Ecology↗

USGS2024

Ungulate personality and the human shield contribute to long-distance migration loss

Long-distance ungulate migrations are declining and past research has focused on preserving migration paths where habitat fragmentation and loss disrupts movement corridors. However, changing residency-migration tradeoffs are the stronger driver of long-distance migration loss in some populations. The human shield effect relative to predation risk and anthropogenic food resources likely shapes these tradeoffs, but individual animals also vary in their propensity to tolerate proximity to humans and developed areas. We investigated how personality relative to human-habituation affects migration behavior. We categorized elk as bold or shy based on use of anthropogenic food resources identified through a clustering algorithm applied to GPS collar data. Bold elk were 4 times more likely to select wintering areas close to human activity and migrated 60% shorter distances compared to shy elk. As a result, elk wintering grounds were spatially structured such that conflict- and disease-prone individuals selected areas adjacent to human activity. Our results suggest that bold personality traits act as a precursor to human-habituation, which permits bold elk to reap the forage and predation rewards that occur in suburban landscapes. A multi-pronged approach beyond just maintaining habitat corridors may be necessary to conserve long-distance migrations for species that can become human-habituated.

BioRxiv↗

USGS2016

Sediment accumulation in prairie wetlands under a changing climate: The relative roles of landscape and precipitation

Sediment accumulation threatens the viability and hydrologic functioning of many naturally formed depressional wetlands across the interior regions of North America. These wetlands provide many ecosystem services and vital habitats for diverse plant and animal communities. Climate change may further impact sediment accumulation rates in the context of current land use patterns. We estimated sediment accretion in wetlands within a region renowned for its large populations of breeding waterfowl and migrant shorebirds and examined the relative roles of precipitation and land use context in the sedimentation process. We modeled rates of sediment accumulation from 1971 through 2100 using the Revised Universal Soil Loss Equation (RUSLE) with a sediment delivery ratio and the Unit Stream Power Erosion Deposition model (USPED). These models predicted that by 2100, 21–33 % of wetlands filled completely with sediment and 27–46 % filled by half with sediments; estimates are consistent with measured sediment accumulation rates in the region reported by empirical studies. Sediment accumulation rates were strongly influenced by size of the catchment, greater coverage of tilled landscape within the catchment, and steeper slopes. Conservation efforts that incorporate the relative risk of infilling of wetlands with sediments, thus emphasizing areas of high topographic relief and large watersheds, may benefit wetland-dependent biota.

Prairie Pothole region↗

USGS2015

Two tickets to paradise: multiple dispersal events in the founding of hoary bat populations in Hawai'i

The Hawaiian islands are an extremely isolated oceanic archipelago, and their fauna has long served as models of dispersal in island biogeography. While molecular data have recently been applied to investigate the timing and origin of dispersal events for several animal groups including birds, insects, and snails, these questions have been largely unaddressed in Hawai'i's only native terrestrial mammal, the Hawaiian hoary bat, Lasiurus cinereus semotus . Here, we use molecular data to test the hypotheses that (1) Hawaiian L . c . semotus originated via dispersal from North American populations of L . c . cinereus rather than from South American L . c . villosissimus , and (2) modern Hawaiian populations were founded from a single dispersal event. Contrary to the latter hypothesis, our mitochondrial data support a biogeographic history of multiple, relatively recent dispersals of hoary bats from North America to the Hawaiian islands. Coalescent demographic analyses of multilocus data suggest that modern populations of Hawaiian hoary bats were founded no more than 10 kya. Our finding of multiple evolutionarily significant units in Hawai'i highlights information that should be useful for re-evaluation of the conservation status of hoary bats in Hawai'i.

PLoS ONE↗