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At least 145 records · Page 8Linked to original sources
USGS2013

CO 2 uptake and ecophysiological parameters of the grain crops of midcontinent North America: estimates from flux tower measurements

We analyzed net CO 2 exchange data from 13 flux tower sites with 27 site-years of measurements over maize and wheat fields across midcontinent North America. A numerically robust “light-soil temperature-VPD”-based method was used to partition the data into photosynthetic assimilation and ecosystem respiration components. Year-round ecosystem-scale ecophysiological parameters of apparent quantum yield, photosynthetic capacity, convexity of the light response, respiration rate parameters, ecological light-use efficiency, and the curvature of the VPD-response of photosynthesis for maize and wheat crops were numerically identified and interpolated/extrapolated. This allowed us to gap-fill CO 2 exchange components and calculate annual totals and budgets. VPD-limitation of photosynthesis was systematically observed in grain crops of the region (occurring from 20 to 120 days during the growing season, depending on site and year), determined by the VPD regime and the numerical value of the curvature parameter of the photosynthesis-VPD-response, σ VPD . In 78% of the 27 site-years of observations, annual gross photosynthesis in these crops significantly exceeded ecosystem respiration, resulting in a net ecosystem production of up to 2100 g CO 2 m −2 year −1 . The measurement-based photosynthesis, respiration, and net ecosystem production data, as well as the estimates of the ecophysiological parameters, provide an empirical basis for parameterization and validation of mechanistic models of grain crop production in this economically and ecologically important region of North America.

Agriculture, Ecosystems and Environment↗
USGS2012

Introduction to emergent wetlands: Chapter A in Emergent wetlands status and trends in the northern Gulf of Mexico: 1950-2010

Throughout the past century, emergent wetlands have been declining across the Gulf of Mexico. Emergent wetland ecosystems provide a plethora of resources including plant and wildlife habitat, commercial and recreational economic activity, water quality improvement, and natural barriers against storms. As emergent wetland losses increase, so does the need for information on the causes and effects of these losses, for emergent wetland mapping, for monitoring and restoration efforts, and for increased education. The U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency’s Gulf of Mexico Program Office (EPA GMPO) are committed to providing the best science to restore, enhance, and protect these important ecosystems. The Emergent Wetlands Status and Trends Report is a continuation of the completed Seagrass Status and Trends in the Northern Gulf of Mexico Report (Handley and others, 2007), both of which serve to update the EPA GMPO Status and Trends of Emergent and Submerged Vegetated Habitats of Gulf of Mexico Coastal Waters, USA Report (Duke and Kruczynski, 1992). The Emergent Wetlands Status and Trends Report is also part of the Gulf of Mexico Alliance Ecosystems Integration and Assessment Priority Issue Team’s work plan to provide resources that will aid in the ecological and economic enhancement of the Gulf of Mexico region. The purpose of this report is to provide scientists, managers, and citizens with valuable baseline information on the status and trends of emergent wetlands along the coast of the Gulf of Mexico. The study upon which this report is based examines the emergent wetlands of eight individual estuarine areas within the northern Gulf of Mexico region and presents statewide summaries for Texas, Louisiana, Mississippi, Alabama, and Florida. Each estuarine area is detailed in vignettes that address current status and historical trends of estuarine and palustrine emergent wetlands, emergent wetlands mapping and monitoring, causes of status change, restoration and enhancement activities, background information for the study area, and the methodology employed to analyze and document the historical trends and current status of emergent wetlands. The eight individual estuarine areas examined in this report are:  Corpus Christi/ Nueces/Aransas Bays, Tex.  Galveston Bay, Tex.  Barataria/Terrebonne Bay, La.  Mississippi Delta, La.  Mississippi Sound, Miss.  Mobile Bay, Ala.  Florida Panhandle, Fla.  Tampa Bay, Fla.

Report↗
USGS2015

Fire effects on aquatic ecosystems: An assessment of the current state of the science

Fire is a prevalent feature of many landscapes and has numerous and complex effects on geological, hydrological, ecological, and economic systems. In some regions, the frequency and intensity of wildfire have increased in recent years and are projected to escalate with predicted climatic and landuse changes. In addition, prescribed burns continue to be used in many parts of the world to clear vegetation for development projects, encourage desired vegetation, and reduce fuel loads. Given the prevalence of fire on the landscape, authors of papers in this special series examine the complexities of fire as a disturbance shaping freshwater ecosystems and highlight the state of the science. These papers cover key aspects of fire effects that range from vegetation loss and recovery in watersheds to effects on hydrology and water quality with consequences for communities (from algae to fish), food webs, and ecosystem processes (e.g., organic matter subsidies, nutrient cycling) across a range of scales. The results presented in this special series of articles expand our knowledge of fire effects in different biomes, water bodies, and geographic regions, encompassing aquatic population, community, and ecosystem responses. In this overview, we summarize each paper and emphasize its contributions to knowledge on fire ecology and freshwater ecosystems. This overview concludes with a list of 7 research foci that are needed to further our knowledge of fire effects on aquatic ecosystems, including research on: 1) additional biomes and geographic regions; 2) additional habitats, including wetlands and lacustrine ecosystems; 3) different fire severities, sizes, and spatial configurations; and 4) additional response variables (e.g., ecosystem processes) 5) over long (>5 y) time scales 6) with more rigorous study designs and data analyses, and 7) consideration of the effects of fire management practices and policies on aquatic ecosystems.

Freshwater Science↗
USGS2006

Range expansion of an exotic Siberian prawn to the Lower Snake River

The introduction of non-native plant and animal species in aquatic systems is of increasing concern because of their potentially negative ecological and economic impacts (Sytsma et al. 2004). There are many examples of food web repercussions resulting from non-native invertebrate introductions. For example, in Flathead Lake, Montana, the kokanee salmon (Oncorhynchus nerka) population crashed after the introduction of a planktivorous mysid, My-sis relicta caused restructuring of the zooplankton community (Spencer et al. 1991) and the introduc-tion of the spiny water flea (Bythotrephes spp.) to the Great Lakes also restructured zooplankton communities (Barbiero and Tuchman 2004). The zebra mussel (Dreissena polymorpha) has nearly extirpated some native unionid clams through competition for food and shell fouling (Strayer 1999). In San Francisco Bay, California, one of the most highly invaded estuaries in the world (Cohen and Carlton 1998), the benthic fauna has been highly modified by the introduction of hundreds of exotic invertebrates including the Chinese mitten crab (Eriocheir sinensis) and the Asian clam, Potamocorbula amurensis. Non-native invertebrate species, including the New Zealand mud snail (Potamopyrgus antipodarum) and an-other Asian clam, Corbicula fluminea, have also been introduced to the Columbia River (Sytsma et al. 2004), but the ecological effects to Columbia River species are largely unknown.

Washington↗
USGS2018

Behavioral differences following ingestion of large meals and consequences for management of a harmful invasive snake: A field experiment

Many snakes are uniquely adapted to ingest large prey at infrequent intervals. Digestion of large prey is metabolically and aerobically costly, and large prey boluses can impair snake locomotion, increasing vulnerability to predation. Cessation of foraging and use of refugia with microclimates facilitating digestion are expected to be strategies employed by free‐ranging snakes to cope with the demands of digestion while minimizing risk of predation. However, empirical observations of such submergent behavior from field experiments are limited. The brown treesnake (Serpentes: Colubridae: Boiga irregularis ) is a nocturnal, arboreal, colubrid snake that was accidentally introduced to the island of Guam, with ecologically and economically costly consequences. Because tools for brown treesnake damage prevention generally rely on snakes being visible or responding to lures or baits while foraging, cessation of foraging activities after feeding would complicate management. We sought to characterize differences in brown treesnake activity, movement, habitat use, and detectability following feeding of large meals (rodents 33% of the snake's unfed body mass) via radio telemetry, trapping, and visual surveys. Compared to unfed snakes, snakes in the feeding treatment group showed drastic decreases in hourly and nightly activity rates, differences in refuge height and microhabitat type, and a marked decrease in detectability by trapping and visual surveys. Depression of activity lasted approximately 5–7 days, a period that corresponds to previous studies of brown treesnake digestion and cycles of detectability. Our results indicate that management strategies for invasive brown treesnakes need to account for cycles of unavailability and underscore the importance of preventing spread of brown treesnakes to new environments where large prey are abundant and periods of cryptic behavior are likely to be frequent. Characterization of postfeeding behavior changes provides a richer understanding of snake ecology and foraging models for species that consume large prey.

Ecology and Evolution↗
USGS2025

Management strategy evaluation to assess trade-offs associated with invasive Blue Catfish fisheries and predation impacts

Objective Many species are intentionally introduced beyond their native range to provide benefits to humans (e.g., food, recreation, or biocontrol). However, introduced species can become invasive and can harm native species, prompting resource managers to explore options to simultaneously conserve native biota and enhance fishing opportunities. Management of Chesapeake Bay Blue Catfish Ictalurus furcatus is complicated because the species supports a renowned trophy fishery and commercial and recreational harvest but also negatively affects native species. Consequently, there is uncertainty and disagreement on how to balance trade-offs associated with varying stakeholder interests. Methods We used a management strategy evaluation to project Blue Catfish population dynamics into the future under different fishery policies to understand whether fishery yield, trophy fishing opportunities, and predation on the economically and ecologically important blue crab Callinectes sapidus could be optimized in the James River, a Chesapeake Bay subestuary. Results Simulated population trajectories indicated that objectives related to maintaining fisheries and conserving prey populations were in conflict. Policies that increased the yield and abundance of trophy-size Blue Catfish (≥100 cm total length) generally increased predation on the blue crab, which supports a valuable fishery. Intense harvest of smaller length-classes and protection of larger Blue Catfish yielded outcomes in which trophy fish abundance increased and blue crab predation declined compared to baseline conditions. However, these outcomes were generally associated with lower Blue Catfish yields after 25 years. There were zero scenarios in which the fishery yield increased and blue crab predation decreased after 25 years. Policies limiting the harvest of small Blue Catfish resulted in large population abundances, suggesting that reducing the abundance of small fish could be important for reducing impacts on native species. Conclusions This study supports the importance of management planning to develop objectives and performance measures based on an improved understanding of trade-offs associated with harvest management for a nonnative fish with economic value.

Virginia↗
USGS2020

Characterization of a Y-specific duplication/insertion of the anti-Mullerian hormone type II receptor gene based on a chromosome-scale genome assembly of yellow perch, Perca flavescens

Yellow perch, Perca flavescens , is an ecologically and economically important species native to a large portion of the northern United States and southern Canada and is also a promising candidate species for aquaculture. However, no yellow perch reference genome has been available to facilitate improvements in both fisheries and aquaculture management practices. By combining Oxford Nanopore Technologies long-reads, 10X Genomics Illumina short linked reads and a chromosome contact map produced with Hi-C, we generated a high-continuity chromosome-scale yellow perch genome assembly of 877.4 Mb. It contains, in agreement with the known diploid chromosome yellow perch count, 24 chromosome-size scaffolds covering 98.8% of the complete assembly (N50 = 37.4 Mb, L50 = 11). We also provide a first characterization of the yellow perch sex determination locus that contains a male-specific duplicate of the anti-Mullerian hormone type II receptor gene ( amhr2by ) inserted at the proximal end of the Y chromosome (chromosome 9). Using this sex-specific information, we developed a simple PCR genotyping assay which accurately differentiates XY genetic males ( amhr2by + ) from XX genetic females ( amhr2by − ). Our high-quality genome assembly is an important genomic resource for future studies on yellow perch ecology, toxicology, fisheries and aquaculture research. In addition, characterization of the amhr2by gene as a candidate sex-determining gene in yellow perch provides a new example of the recurrent implication of the transforming growth factor beta pathway in fish sex determination, and highlights gene duplication as an important genomic mechanism for the emergence of new master sex determination genes.

Molecular Ecology Resources↗
USGS2014

Assessing the value of the Central Everglades Planning Project (CEPP) in Everglades restoration: an ecosystem service approach

This study identifies a full range of ecosystem services that could be affected by a restoration project in the central Everglades and monetizes the economic value of a subset of these services using existing data. Findings suggest that the project will potentially increase many ecosystem services that have considerable economic value to society. The ecosystem services monetized within the scope of this study are a subset of the difference between the future-with the Central Everglades Planning Project (CEPP) and the future-without CEPP, and they totaled ~ $1.8 billion USD at a 2.5% discount rate. Findings suggest that the use of ecosystem services in project planning and communications may require acknowledgment of the difficulty of monetizing important services and the limitations associated with using only existing data and models. Results of this study highlight the need for additional valuation efforts in this region, focused on those services that are likely to be impacted by restoration activities but were notably challenging to value in this assessment due to shortages of data.

Florida↗
USGS2016

Tidal hydrodynamics under future sea level rise and coastal morphology in the Northern Gulf of Mexico

This study examines the integrated influence of sea level rise (SLR) and future morphology on tidal hydrodynamics along the Northern Gulf of Mexico (NGOM) coast including seven embayments and three ecologically and economically significant estuaries. A large-domain hydrodynamic model was used to simulate astronomic tides for present and future conditions (circa 2050 and 2100). Future conditions were simulated by imposing four SLR scenarios to alter hydrodynamic boundary conditions and updating shoreline position and dune heights using a probabilistic model that is coupled to SLR. Under the highest SLR scenario, tidal amplitudes within the bays increased as much as 67% (10.0 cm) because of increases in the inlet cross-sectional area. Changes in harmonic constituent phases indicated that tidal propagation was faster in the future scenarios within most of the bays. Maximum tidal velocities increased in all of the bays, especially in Grand Bay where velocities doubled under the highest SLR scenario. In addition, the ratio of the maximum flood to maximum ebb velocity decreased in the future scenarios (i.e., currents became more ebb dominant) by as much as 26% and 39% in Weeks Bay and Apalachicola, respectively. In Grand Bay, the flood-ebb ratio increased (i.e., currents became more flood dominant) by 25% under the lower SLR scenarios, but decreased by 16% under the higher SLR as a result of the offshore barrier islands being overtopped, which altered the tidal prism. Results from this study can inform future storm surge and ecological assessments of SLR, and improve monitoring and management decisions within the NGOM.

Florida, Louisiana↗
USGS2011

Valuing ecosystem and economic services across land-use scenarios in the Prairie Pothole Regions of the Dakotas, USA

This study uses biophysical values derived for the Prairie Pothole Region (PPR) of North and South Dakota, in conjunction with value transfer methods, to assess environmental and economic tradeoffs under different policy-relevant land-use scenarios over a 20-year period. The ecosystem service valuation is carried out by comparing the biophysical and economic values of three focal services (i.e. carbon sequestration, reduction in sedimentation, and waterfowl production) across three focal land uses in the region [i.e. native prairie grasslands, lands enrolled in the Conservation Reserve and Wetlands Reserve Programs (CRP/WRP), and cropland]. This study finds that CRP/WRP lands cannot mitigate (hectare for hectare) the loss of native prairie from a social welfare standpoint. Land use scenarios where native prairie loss was minimized, and CRP/WRP lands were increased, provided the most societal benefit. The scenario modeling projected native prairie conversion to cropland over the next 20 years would result in a social welfare loss valued at over $4 billion when considering the study's three ecosystem services, and a net loss of about $3.4 billion when reductions in commodity production are accounted for.

North Dakota;South Dakota↗
USGS2010

Valuing ecosystem services from wetlands restoration in the Mississippi Alluvial Valley

This study assesses the value of restoring forested wetlands via the U.S. government's Wetlands Reserve Program (WRP) in the Mississippi Alluvial Valley by quantifying and monetizing ecosystem services. The three focal services are greenhouse gas (GHG) mitigation, nitrogen mitigation, and waterfowl recreation. Site- and region-level measurements of these ecosystem services are combined with process models to quantify their production on agricultural land, which serves as the baseline, and on restored wetlands. We adjust and transform these measures into per-hectare, valuation-ready units and monetize them with prices from emerging ecosystem markets and the environmental economics literature. By valuing three of the many ecosystem services produced, we generate lower bound estimates for the total ecosystem value of the wetlands restoration. Social welfare value is found to be between $1435 and $1486/ha/year, with GHG mitigation valued in the range of $171 to $222, nitrogen mitigation at $1248, and waterfowl recreation at $16. Limited to existing markets, the estimate for annual market value is merely $70/ha, but when fully accounting for potential markets, this estimate rises to $1035/ha. The estimated social value surpasses the public expenditure or social cost of wetlands restoration in only 1 year, indicating that the return on public investment is very attractive for the WRP. Moreover, the potential market value is substantially greater than landowner opportunity costs, showing that payments to private landowners to restore wetlands could also be profitable for individual landowners. ?? 2009 Elsevier B.V.

Ecological Economics↗
USGS2016

Tolerance to multiple climate stressors: A case study of Douglas-fir drought and cold hardiness

Drought and freeze events are two of the most common forms of climate extremes which result in tree damage or death, and the frequency and intensity of both stressors may increase with climate change. Few studies have examined natural covariation in stress tolerance traits to cope with multiple stressors among wild plant populations. We assessed the capacity of coastal Douglas‐fir ( Pseudotsuga menziesii var. menziesii ), an ecologically and economically important species in the northwestern USA, to tolerate both drought and cold stress on 35 populations grown in common gardens. We used principal components analysis to combine drought and cold hardiness trait data into generalized stress hardiness traits to model geographic variation in hardiness as a function of climate across the Douglas‐fir range. Drought and cold hardiness converged among populations along winter temperature gradients and diverged along summer precipitation gradients. Populations originating in regions with cold winters had relatively high tolerance to both drought and cold stress, which is likely due to overlapping adaptations for coping with winter desiccation. Populations from regions with dry summers had increased drought hardiness but reduced cold hardiness, suggesting a trade‐off in tolerance mechanisms. Our findings highlight the necessity to look beyond bivariate trait–climate relationships and instead consider multiple traits and climate variables to effectively model and manage for the impacts of climate change on widespread species.

California, Oregon, Washington↗
USGS2019

Long-term population dynamics of dreissenid mussels (Dreissena polymorpha and D. rostriformis): A cross-system analysis

Dreissenid mussels (including the zebra mussel Dreissena polymorpha and the quagga mussel D. rostriformis ) are among the world's most notorious invasive species, with large and widespread ecological and economic effects. However, their long‐term population dynamics are poorly known, even though these dynamics are critical to determining impacts and effective management. We gathered and analyzed 67 long‐term (>10 yr) data sets on dreissenid populations from lakes and rivers across Europe and North America. We addressed five questions: (1) How do Dreissena populations change through time? (2) Specifically, do Dreissena populations decline substantially after an initial outbreak phase? (3) Do different measures of population performance (biomass or density of settled animals, veliger density, recruitment of young) follow the same patterns through time? (4) How do the numbers or biomass of zebra mussels or of both species combined change after the quagga mussel arrives? (5) How does body size change over time? We also considered whether current data on long‐term dynamics of Dreissena populations are adequate for science and management. Individual Dreissena populations showed a wide range of temporal dynamics, but we could detect only two general patterns that applied across many populations: (1) Populations of both species increased rapidly in the first 1–2 yr after appearance, and (2) quagga mussels appeared later than zebra mussels and usually quickly caused large declines in zebra mussel populations. We found little evidence that combined Dreissena populations declined over the long term. Different measures of population performance were not congruent; the temporal dynamics of one life stage or population attribute cannot generally be accurately inferred from the dynamics of another. We found no consistent patterns in the long‐term dynamics of body size. The long‐term dynamics of Dreissena populations probably are driven by the ecological characteristics (e.g., predation, nutrient inputs, water temperature) and their temporal changes at individual sites rather than following a generalized time course that applies across many sites. Existing long‐term data sets on dreissenid populations, although clearly valuable, are inadequate to meet research and management needs. Data sets could be improved by standardizing sampling designs and methods, routinely collecting more variables, and increasing support.

Ecosphere↗
USGS2022

Grassland conservation supports migratory birds and produces economic benefits for the commercial beekeeping industry in the U.S. Great Plains

Although declines in grassland birds have been documented, national initiatives to conserve grasslands and their biota have fallen short in part because the non-market values of natural ecosystems and species are often not recognized in political decision making. Identifying shared, anthropogenic threats faced by market-valued and non-market-valued species may generate additional support for grassland conservation. We quantify the relationship between the market value of grasslands to commercial beekeepers and the importance of grasslands for birds of conservation concern in North and South Dakota. Our models estimated beekeeping annual revenue increased by $7525 USD and grassland bird abundances increased 2 to 7% per 10-km 2 increase in grassland area. We estimated grassland conversion from 2006 to 2012 resulted in a $2.0 to $2.8 M USD decrease in annual revenue for beekeepers in the Dakotas. Through this study we demonstrate both the market value of grasslands to commercial beekeepers and the non-market benefits of grasslands in supporting migratory birds and discuss the implications of future land-use change. As grassland conversion and subsequent biodiversity loss continue, understanding the co-benefits of grassland conservation may be necessary to illuminate their contributions to society.

North Dakota, South Dakota↗
USGS2021

Effects of variable-density thinning on non-native understory plants in coniferous forests of the Pacific Northwest

Old-growth forests serve as critical habitat for many sensitive species, but management practices have diminished their prevalence, and former regions of old-growth are now dominated by second-growth stands lacking the structural heterogeneity, diversity, and species richness that these older forests possess. In western Washington state in the Pacific Northwest of the United States, the Olympic Habitat Development Study was designed to address this issue and hasten the development of specific old-growth features in second-growth stands using variable-density thinning. One concern with such methods, however, is the potential to introduce non-native plants, which can have negative ecological and economic impacts. Here, we examine how variable-density thinning influences desirable forest characteristics, such as increased plant species diversity, versus the less desirable effects of non-native plant species introduction. We test two hypotheses regarding plant invasions. First, thinning would promote establishment of non-native, shade-intolerant species, but their abundance would gradually decline over time. Second, thinning disturbance and increased heterogeneity of canopy cover would initially promote understory richness of all species, although richness would decline over time with canopy closure and increased cover of shrubs and regenerating trees. We found that the number and cover of non-native species initially increased after thinning, peaking at 16 species present in variable-density thinned treatments in year three. By year 17, 11 species remained throughout the seven 6.5 ha treatment plots sampled, and cover was negligible. As predicted, species richness increased following thinning, however, native species richness remained elevated through year 17, contrary to our hypothesis. Furthermore, native species diversity also increased following thinning and remained higher in thinned treatments than controls through year 17. Our results show that variable-density thinning in temperate coniferous forests can enhance native, but not exotic, plant richness and diversity in the long term.

Washington↗
USGS2023

Climate-induced shifts in grassland bird nesting phenology have implications for grassland management

Grasslands are among the most impacted ecosystems globally. In the midcontinent of North America, a > 80% loss of grasslands has made their conservation a major priority for resource managers. Grassland ecosystems evolved under periodic disturbances; consequently, grassland management often involves regular actions such as grazing, haying, or burning to maintain ecosystem integrity. The timing of such practices has direct implications on grassland ecology, agricultural economics, and survival and fecundity of grassland nesting birds (hereafter grassland birds). We conducted a meta-analysis on the nesting phenology of grassland birds throughout North America, focusing on nest-survival literature. We constructed a well-fitting model to predict median date of expected nest departure (hereafter fledge date) for grassland birds across the midcontinent. Predictions from our model demonstrate considerable spatial variation in median nesting phenology that is predictable using a spatially explicit spring phenology index. Median fledge dates were 8 or 13 days earlier in years of extreme weather conditions (dry or wet, respectively) than in years of average conditions. Species that generally nest in taller vegetation tended to have later median nest phenologies than those using shorter vegetation. Our results incorporate the most rigorous information available in the literature on nesting phenology of 36 grassland bird species and improve information available to managers about nesting phenology of grassland birds in the midcontinent of North America. Our predictions approximate the day when one-half of the nesting efforts would be complete for a given area within the midcontinent grasslands and can inform management and conservation decisions about the timing of management actions in grassland ecosystems.

Global Ecology and Conservation↗
USGS2024

Genetic analysis of harvest samples reveals population structure in a highly mobile generalist carnivore

Delineating wildlife population boundaries is important for effective population monitoring and management. The bobcat ( Lynx rufus ) is a highly mobile generalist carnivore that is ecologically and economically important. We sampled 1225 bobcats harvested in South Dakota, USA (2014–2019), of which 878 were retained to assess genetic diversity and infer population genetic structure using 17 microsatellite loci. We assigned individuals to genetic clusters ( K ) using spatial and nonspatial Bayesian clustering algorithms and quantified differentiation ( F ST and GST″ ) among clusters. We found support for population genetic structure at K = 2 and K = 4, with pairwise F ST and GST″ values indicating weak to moderate differentiation, respectively, among clusters. For K = 2, eastern and western clusters aligned closely with historical bobcat management units and were consistent with a longitudinal suture zone for bobcats previously identified in the Great Plains. We did not observe patterns of population genetic structure aligning with major rivers or highways. Genetic divergence observed at K = 4 aligned roughly with ecoregion breaks and may be associated with environmental gradients, but additional sampling with more precise locational data may be necessary to validate these patterns. Our findings reveal that cryptic population structure may occur in highly mobile and broadly distributed generalist carnivores, highlighting the importance of considering population structure when establishing population monitoring programs or harvest regulations. Our study further demonstrates that for elusive furbearers, harvest can provide an efficient, broad-scale sampling approach for genetic population assessments.

South Dakota↗
USGS2020

Fostering real-time climate adaptation: Analyzing past, current, and forecast temperature to understand the dynamic risk to Hawaiian honeycreepers from avian malaria

Various vector control options are increasingly being considered to safeguard forest birds in their natural habitats from avian malaria transmission. However, vector control options require localized deployment that is not logistically, ethically, ecologically, nor economically viable everywhere and all the time. Based on thermal tolerances of the sporogonic stages of avian malaria (Plasmodium relictum) parasite and its vector, the southern house mosquito (Culex quinquefasciatus), we examined the long-term weather trends for three high value, forest bird refuges (Alakai Wilderness Preserve on Kaua’i, Hanawi Natural Area Reserve on Maui, and Hakalau Forest National Wildlife Refuge on Hawai’i Island) to understand the temporal and site-specific differences of temperature-driven suitability for localized avian malaria transmission. On average, Alakai had mean ambient temperatures suitable for both the vector’s immature stage development and parasite sporogonic development most of the time (85.3%), indicating that observed variability in vector abundance or disease transmission may be driven by other factors. At higher elevation sites like Hakalau and Hanawi, current mean ambient temperatures suitable only for vector development prevail (91.7% and 96.6%, respectively), while mean ambient temperatures for both vector and parasite sporogonic development seldom occur (4.4% and 0% respectively). Our results not only show differences in the temperature suitability for transmission across elevation, but also different levels of vulnerability to avian malaria transmission with any additional projected increase in temperature. For instance, under a conservative warming scenario of 1.0 °C, the joint temperature suitability of parasite and vector development increases at higher elevation sites such as Hakalau (+35.8%) and Hanawi (+15.4%). While mean ambient temperatures suitable for both vector and parasite development already occur most of the time at Alakai, the occurrence also increases (+8.4%) as well under this conservative warming scenario. By linking current site-specific weather data to real-time weather forecasts, we developed a real-time avian malaria warning system to assist managers in identifying conditions when vector control is most needed at these three selected study sites. This online tool determines when conditions are likely to be suitable for local development of P. relictum and C. quinquefasciatus at Alakai, Hanawi, and Hakalau. This tool illustrates how managers can incorporate climate and current weather patterns into decision making without having to consider the uncertainties of long-term climatic and ecological projections.

Hawaii↗