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USGS2021

Range eclipse leads to tenuous survival of a rare lizard species on a barrier atoll

Rediscovery of living populations of a species that was presumed to be extirpated can generate new narratives for conservation in areas suffering from losses in biodiversity. We used field observations and DNA sequence data to verify the rediscovery of the Critically Endangered scincid lizard Emoia slevini on Dåno′, an islet off the coast of Guam in the southern Mariana Islands, where for > 20 years it had been considered possibly extirpated. Endemic to the Marianas, E. slevini has declined throughout its range and no longer occurs on as many as five islands from which it was historically known, most likely because of interactions with invasive species and loss of native forest. Our results show that individuals from Dåno′, the type locality for E. slevini , are genetically similar but not identical to E. slevini on Sarigan and Alamagan to the north, and that E. slevini is a close evolutionary relative to another congener in the southern Marianas that is currently recognized as E moia atrocostata but probably represents an undescribed species in this archipelago. We also show that other, more broadly distributed species of Emoia occurring on Dåno′ are distant relatives to E. slevini and the Mariana lineage of E. atrocostata , providing further evidence of the distinctiveness of these taxa. The rediscovery of E. slevini on Dåno′ following rodent eradication and culling of a population of monitor lizards suggests that management of invasive species is key to the recovery of this skink in the Mariana Islands, and that a range eclipse on the larger neighbouring island of Guam best explains why the rediscovery took place at the periphery of the species’ historic range. A Chamorro abstract can be found in the supplementary material.

Dåno′, Guam↗

USGS2009

Processes of wetland loss in India

Wetlands in India supply crucial human and animal needs such as drinking water, protein production, fodder, water purification, wildlife habitat, and flood storage. Increased appreciation of uses and threats is essential to protect wetlands where justified. Three quarters of India's population is rural, it places great demands on India's wetlands and losses continue to occur. This paper is based on extensive discussions with natural resource managers, government employees, farmers, academicians, and resource users at dozens of sites in India, as well as an extensive literature search. Twelve important kinds of wetland loss are identified and mechanisms believed to be causing them discussed: (1) agricultural conversion, (2) direct deforestation, (3) hydrologie alteration, (4) inundation, (5) defoliation, (6) altered upper watersheds, (7) accumulative water demands, (8) water quality degradation, (9) wetland consolidation, (10) global climate change, (11) ground-water depletion, (12) exotic species and biodiversity. Wetland understanding, management, and Public awareness in India must continue growing if wetland resources are to remain functional.

Environmental Conservation↗

USGS2014

Change in agricultural land use constrains adaptation of national wildlife refuges to climate change

Land-use change around protected areas limits their ability to conserve biodiversity by altering ecological processes such as natural hydrologic and disturbance regimes, facilitating species invasions, and interfering with dispersal of organisms. This paper informs USA National Wildlife Refuge System conservation planning by predicting future land-use change on lands within 25 km distance of 461 refuges in the USA using an econometric model. The model contained two differing policy scenarios, namely a ‘business-as-usual’ scenario and a ‘pro-agriculture’ scenario. Regardless of scenario, by 2051, forest cover and urban land use were predicted to increase around refuges, while the extent of range and pasture was predicted to decrease; cropland use decreased under the business-as-usual scenario, but increased under the pro-agriculture scenario. Increasing agricultural land value under the pro-agriculture scenario slowed an expected increase in forest around refuges, and doubled the rate of range and pasture loss. Intensity of land-use change on lands surrounding refuges differed by regions. Regional differences among scenarios revealed that an understanding of regional and local land-use dynamics and management options was an essential requirement to effectively manage these conserved lands. Such knowledge is particularly important given the predicted need to adapt to a changing global climate.

Environmental Conservation↗

USGS2023

Out of the frying pan and into the fire: Effects of volcanic heat and other stressors on the conservation of a critically endangered plant in Hawaiʻi

Loss of local biodiversity resulting from abrupt environmental change is a significant environmental problem throughout the world. Extinctions of plants are particularly important yet are often overlooked. Drawing from a case in Hawai‘i, a global hotspot for plant and other extinctions, we demonstrate an effort to better understand and determine priorities for the management of an endangered plant (‘Ihi makole or Portulaca sclerocarpa ) in the face of rapid and extreme environmental change. Volcanic heat emissions and biological invasions have anecdotally been suggested as possible threats to the species. We integrated P. sclerocarpa outplanting with efforts to collect geological and ecological data to gauge the role of elevated soil temperatures and invasive grasses in driving P. sclerocarpa mortality and population decline. We measured soil temperature, soil depth, surrounding cover and P. sclerocarpa survivorship over three decades. The abundance of wild P. sclerocarpa decreased by 99.7% from the 1990s to 2021. Only 51% of outplantings persisted through 3–4 years. Binomial regression and structural equation modelling revealed that, among the variables we analysed, high soil temperatures were most strongly associated with population decline. Finding the niche where soil temperatures are low enough to allow P. sclerocarpa survival but high enough to limit other agents of P. sclerocarpa mortality may be necessary to increase population growth of this species.

Hawaii↗

USGS2026

Ten new insights in climate science 2025

Interdisciplinary understanding is vital for delivering sound climate policy advice. However, navigating the ever-growing and increasingly diverse scholarly literature on climate change is challenging for any individual researcher. This annual synthesis highlights and explains recent advances across a variety of fields of climate change research. This year, the 10 insights focus on: (1) the record-warmth of 2023/2024 and the elevated Earth energy imbalance; (2) acceleration of ocean warming and intensifying marine heatwaves; (3) northern land carbon sinks under strain; (4) reinforcing feedback between biodiversity loss and climate change; (5) accelerated depletion of groundwater; (6) global dengue incidence; (7) global income losses and labour productivity declines; (8) strategic scaling of CDR; (9) integrity challenges in carbon credit markets and emerging responses; and (10) effective policy mixes for emissions reductions. The insights have been written to be accessible to researchers from different fields, serving as entry-points to specific topics, as well as providing an overview of the evolving landscape of climate change research. In the final section, the insights are used to develop overarching policy-relevant messages. This paper provides the basis for a science-policy report that was shared with all Party delegations ahead of COP30 in Belém, Brazil.

Global Sustainability↗

USGS2025

Potential interactions between birds and floating photovoltaic solar energy: Spatially informed species vulnerabilities, techno-ecological risks, and sustainability trade-offs

Floating photovoltaics (floating solar panels; FPV) can reduce the negative impacts of solar energy development in terrestrial environments, but their effects on freshwater ecosystems remain poorly understood. We examined potential FPV interactions with avian biodiversity, using previously modeled technical potential of FPV in the northeastern United States. We developed a vulnerability index based on avian species’: (i) morphological traits, (ii) level of conservation concern, and (iii) habitat requirements. Using eBird participatory science data, we assessed the risk of FPV to 291 species of birds occurring at FPV-suitable waterbodies based on their vulnerability index and estimated relative abundance at each location. The greatest risk of FPVs to birds was associated with waterbodies near the Atlantic coast and Great Lakes, and most (80%) of these high-risk waterbodies were smaller waterbodies. Because the avian risk at FPV-suitable waterbodies was not correlated with estimated energy generation, reducing risk to birds might not require energy trade-offs. Moreover, avoiding FPV installations at waterbodies predicted to pose high risk to birds is likely to return social and recreational benefits while minimizing risk of biofouling. Our analysis provides a framework for proactively evaluating risk, reducing potential adverse impacts of FPV to birds, and identifying cobenefits of sustainable FPV siting across waterscapes.

Connecticut, Delaware, Maine, Maryland, Massachuse↗

USGS2020

Landscape drivers of dynamic change in water quality of US rivers

Water security is a top concern for social well-being and dramatic changes in the availability of freshwater have occurred as a result of human uses and landscape management. Elevated nutrient loading and perturbations to major ion composition have resulted from human activities and have degraded freshwater resources. This study addresses the emerging nature of stream water quality in the 21st century through analysis of concentrations and trends in a wide variety of constituents in streams and rivers of the U.S. Concentrations of fifteen separate water quality parameters including nutrients, major ions, sediment, and specific conductance were analyzed over the period 1982-2012 and a targeted trend analysis was performed from 1992-2012. Although environmental policy is geared toward addressing the long-standing problem of nutrient overenrichment, these efforts have had uneven success, with decreasing nutrient concentrations at urbanized sites and little to no change at agricultural sites. However, freshwaters are being salinized rapidly in all human-dominated land use types. Increasing salinity negatively affects biodiversity, mobilizes sediment-bound contaminants, and increases lead contamination of drinking water but the effects are poorly quantified. Therefore, while efforts to control nutrients are ongoing, rapid salinity increases are ushering in a new set of poorly-defined issues.

Environmental Science & Technology↗

USGS2010

The plight of the bees

The loss of biodiversity is a trend that is garnering much concern. As organisms have evolved mutualistic and synergistic relationships, the loss of one or a few species can have a much wider environmental impact. Since much pollination is facilitated by bees, the reported colony collapse disorder has many worried of widespread agricultural fallout and thus deleterious impact on human foodstocks. In this Feature, Spivak et al. review what is known of the present state of bee populations and provide information on how to mitigate and reverse the trend.

Environmental Science & Technology↗

USGS2010

The need for simultaneous evaluation of ecosystem services and land use change

We are living in a period of massive global change. This rate of change may be almost without precedent in geologic history ( 1 ). Even the most remote areas of the planet are influenced by human activities. Modern landscapes have been highly modified to accommodate a growing human population that the United Nations has forecast to peak at 9.1 billion by 2050. Over this past century, reliance on services from ecosystems has increased significantly and, over past decades, sustainability of our modern, intensively managed ecosystems has been a topic of serious international concern ( 1 ). Numerous papers addressing a particular land-use change effect on specific ecosystem services have recently been published. For example, there is currently great interest in increasing biofuel production to achieve energy inde- pendence goals and recent papers have independently focused attention on impacts of land-use change on single ecosystem services such as carbon sequestration ( 2 ) and many others (e.g., water availability, biodiversity, pollination). However, land-use change clearly affects myriad ecosystem services simultaneously. Hence, a broader perspective and context is needed to evaluate and understand interrelated affects on multiple ecosystem services, especially as we strive for the goal of sustainably managing global ecosystems. Similarly, land uses affect ecosystem services synergistically; single land-use evaluations may be misleading because the overall impact on an ecosystem is not evaluated. A more holistic approach would provide a means and framework to characterize how land-use change affects provisioning of goods and services of complete ecosystems.

Environmental Science & Technology↗

USGS2003

Managing troubled data: Coastal data partnerships smooth data integration

Understanding the ecology, condition, and changes of coastal areas requires data from many sources. Broad-scale and long-term ecological questions, such as global climate change, biodiversity, and cumulative impacts of human activities, must be addressed with databases that integrate data from several different research and monitoring programs. Various barriers, including widely differing data formats, codes, directories, systems, and metadata used by individual programs, make such integration troublesome. Coastal data partnerships, by helping overcome technical, social, and organizational barriers, can lead to a better understanding of environmental issues, and may enable better management decisions. Characteristics of successful data partnerships include a common need for shared data, strong collaborative leadership, committed partners willing to invest in the partnership, and clear agreements on data standards and data policy. Emerging data and metadata standards that become widely accepted are crucial. New information technology is making it easier to exchange and integrate data. Data partnerships allow us to create broader databases than would be possible for any one organization to create by itself.

Environmental Monitoring and Assessment↗

USGS2007

Three-dimensional structure of fluid conduits sustaining an active deep marine cold seep

Cold seeps in deep marine settings emit fluids to the overlying ocean and are often associated with such seafloor flux indicators as chemosynthetic biota, pockmarks, and authigenic carbonate rocks. Despite evidence for spatiotemporal variability in the rate, locus, and composition of cold seep fluid emissions, the shallow subseafloor plumbing systems have never been clearly imaged in three dimensions. Using a novel, high-resolution approach, we produce the first three-dimensional image of possible fluid conduits beneath a cold seep at a study site within the Blake Ridge gas hydrate province. Complex, dendritic features diverge upward toward the seafloor from feeder conduits at depth and could potentially draw flow laterally by up to 10 3 m from the known seafloor seep, a pattern similar to that suggested for some hydrothermal vents. The biodiversity, community structure, and succession dynamics of chemosynthetic communities at cold seeps may largely reflect these complexities of subseafloor fluid flow.

Blake Ridge↗

USGS2007

Climate-induced forest dieback as an emergent global phenomenon: Organized oral session at the Ecological Society of America/Society of Ecological Restoration Joint Meeting; San Jose, California, 5-10 August 2007

An organized oral session at the annual meeting of the Ecological Society of America in San Jose, Calif., posed this question: Is climate-induced drought stress triggering increasing rates and unusual patterns of forest die-off at a global scale? Twenty-nine researchers representing five continents reported on patterns, mechanisms, and projections of forest mortality. Observations include widespread forest dieback or reductions in tree cover and biodiversity in response to drought and warmer temperatures in the African Sahel (Patrick Gonzalez, The Nature Conservancy), Mediterranean and alpine Europe (Jorge Castro, Universidad de Granada), and Argentinean Patagonia (Thomas Kitzberger, Universidad Nacional del Comahue). In contrast, although much Eucalyptus mortality has resulted from recent droughts in Australia, warming trends have been less pronounced in the Southern Hemisphere and it is unclear if contemporary climate-induced tree mortality differs from previous historical drought impacts (Rod Fensham, Queensland Herbarium).

Eos, Transactions, American Geophysical Union↗

USGS2009

Hydroecological factors governing surface water flow on a low-gradient floodplain

"Interrelationships between hydrology and aquatic ecosystems are better understood in streams and rivers compared to their surrounding floodplains. Our goal was to characterize the hydrology of the Everglades ridge and slough floodplain ecosystem, which is valued for the comparatively high biodiversity and connectivity of its parallel-drainage features but which has been degraded over the past century in response to flow reductions associated with flood control. We measured flow velocity, water depth, and wind velocity continuously for 3 years in an area of the Everglades with well-preserved parallel-drainage features (i.e., 200-m wide sloughs interspersed with slightly higher elevation and more densely vegetated ridges). Mean daily flow velocity averaged 0.32 cm s1 and ranged between 0.02 and 0.79 cm s1. Highest sustained velocities were associated with flow pulses caused by water releases from upstream hydraulic control structures that increased flow velocity by a factor of 2–3 on the floodplain for weeks at a time. The highest instantaneous measurements of flow velocity were associated with the passage of Hurricane Wilma in 2005 when the inverse barometric pressure effect increased flow velocity up to 5 cm s1 for several hours. Time-averaged flow velocities were 29% greater in sloughs compared to ridges because of marginally higher vegetative drag in ridges compared to sloughs, which contributed modestly (relative to greater water depth and flow duration in sloughs compared to ridges) to the predominant fraction (86%) of total discharge through the landscape occurring in sloughs. Univariate scaling relationships developed from theory of flow through vegetation, and our field data indicated that flow velocity increases with the square of water surface slope and the fourth power of stem diameter, decreases in direct proportion with increasing frontal area of vegetation, and is unrelated to water depth except for the influence that water depth has in controlling the submergence height of vegetation that varies vertically in its architectural characteristics. In the Everglades the result of interactions among controlling variables was that flow velocity was dominantly controlled by water surface slope variations responding to flow pulses more than spatial variation in vegetation characteristics or fluctuating water depth. Our findings indicate that floodplain managers could, in addition to managing water depth, manipulate the frequency and duration of inflow pulses to manage water surface slope, which would add further control over flow velocities, water residence times, sediment settling, biogeochemical transformations, and other processes that are important to floodplain function."

Water Resources Research↗

USGS2012

Influence of permafrost distribution on groundwater flow in the context of climate-driven permafrost thaw: Example from Yukon Flats Basin, Alaska, United States

Understanding the role of permafrost in controlling groundwater flow paths and fluxes is central in studies aimed at assessing potential climate change impacts on vegetation, species habitat, biogeochemical cycling, and biodiversity. Recent field studies in interior Alaska show evidence of hydrologic changes hypothesized to result from permafrost degradation. This study assesses the hydrologic control exerted by permafrost, elucidates modes of regional groundwater flow for various spatial permafrost patterns, and evaluates potential hydrologic consequences of permafrost degradation. The Yukon Flats Basin (YFB), a large (118,340 km 2 ) subbasin within the Yukon River Basin, provides the basis for this investigation. Model simulations that represent an assumed permafrost thaw sequence reveal the following trends with decreasing permafrost coverage: (1) increased groundwater discharge to rivers, consistent with historical trends in base flow observations in the Yukon River Basin, (2) potential for increased overall groundwater flux, (3) increased spatial extent of groundwater discharge in lowlands, and (4) decreased proportion of suprapermafrost (shallow) groundwater contribution to total base flow. These trends directly affect the chemical composition and residence time of riverine exports, the state of groundwater-influenced lakes and wetlands, seasonal river-ice thickness, and stream temperatures. Presently, the YFB is coarsely mapped as spanning the continuous-discontinuous permafrost transition that model analysis shows to be a critical threshold; thus, the YFB may be on the verge of major hydrologic change should the current permafrost extent decrease. This possibility underscores the need for improved characterization of permafrost and other hydrogeologic information in the region via geophysical techniques, remote sensing, and ground-based observations.

Alaska↗

USGS2023

Variation in leaf reflectance spectra across the California flora partitioned by evolutionary history, geographic origin, and deep time

Evolutionary relatedness underlies patterns of functional diversity in the natural world. Hyperspectral remote sensing has the potential to detect these patterns in plants through inherited patterns of leaf reflectance spectra. We collected leaf reflectance data from across the California flora from plants grown in a common garden. Regions of the reflectance spectra vary in the depth and strength of phylogenetic signal. We also show that these differences are much greater than variation due to the geographic origin of the plant. At the phylogenetic extent of the California flora, spectral variation explained by the combination of ecotypic variation (divergent evolution) and convergent evolution of disparate lineages was minimal (3 to 7 %) but statistically significant. Interestingly, at the extent of a single genus ( Arctostaphylos ) no unique variation could be attributed to geographic origin. However, up to 18% of the spectral variation among Arctostaphylos individuals was shared between phylogeny and intraspecific variation stemming from ecotypic differences (i.e., geographic origin). Future studies could conduct more structured experiments (e.g., transplants or observations along environmental gradients) to disentangle these sources of variation and include other intraspecific variation (e.g., plasticity). We constrain broad scale spectral variability due to ecotypic sources, providing further support for the idea that phylogenetic clusters of species might be detectable through remote sensing. Phylogenetic clusters could represent a valuable dimension of biodiversity monitoring and detection.

California↗

USGS2024

The effect of drying boreal lakes on plants, soils, and microbial communities in lake margin habitats

Decadal scale lake drying in interior Alaska results in lake margin colonization by willow shrub and graminoid vegetation, but the effects of these changes on plant production, biodiversity, soil properties, and soil microbial communities are not well known. We studied changes in soil organic carbon (SOC) and nitrogen (N) storage, plant and microbial community composition, and soil microbial activities in drying and non-drying lakes in the Yukon Flats National Wildlife Refuge. Historic changes in lake area were determined using Landsat imagery. Results showed that SOC storage in drying lake margins declined by 0.13 kg C m −2 yr −1 over 30 years of exposure of lake sediments, with no significant change in soil N. Lake drying resulted in an increase in graminoid and shrub aboveground net primary production (ANPP, +3% yr −1 ) with little change in plant functional composition. Increases in ANPP were similar in magnitude (but opposite in sign) to losses in SOC over a 30-year drying trend. Potential decomposition rates and soil enzyme activities were lower in drying lake margins compared to stable lake margins, possibly due to high salinities in drying lake margin soils. Microbial communities shifted in response to changing plant communities, although they still retained a legacy of the previous plant community. Understanding how changing lake hydrology impacts the ecology and biogeochemistry of lake margin terrestrial ecosystems is an underexamined phenomenon with large impacts to landscape processes.

Alaska↗

USGS1997

Orbital forcing of deep-sea benthic species diversity

Explanations for the temporal and spatial patterns of species biodiversity focus on stability-time, disturbance-mosaic (biogenic microhabitat heterogeneity) and competition-predation (biotic interactions) hypotheses. The stability-time hypothesis holds that high species diversity in the deep sea and in the tropics reflects long-term climatic stability. But the influence of climate change on deep-sea diversity has not been studied and recent evidence suggests that deep-sea environments undergo changes in climatically driven temperature and flux of nutrients and organic-carbon during glacial-interglacial cycles. Here we show that Pliocene (2.85-2.40 Myr) deep-sea North Atlantic benthic ostracod (Crustacea) species diversity is related to solar insolation changes caused by 41,000-yr cycles of Earth's obliquity (tilt). Temporal changes in diversity, as measured by the Shannon- Weiner index, H(S), correlate with independent climate indicators of benthic foraminiferal oxygen-isotope ratios (mainly ice volume) and ostracod Mg:Ca ratios (bottomwater temperature). During glacial periods, H(S) = 0.2-0.6, whereas during interglacials, H(S) = 1.2-1.6, which is three to four times as high. The control of deep-sea benthic diversity by cyclic climate change at timescales of 103-104 yr does not support the stability-time hypothesis because it shows that the deep sea is a temporally dynamic environment. Diversity oscillations reflect large-scale response of the benthic community to climatically driven changes in either thermohaline circulation, bottom temperature (or temperature-related factors) and food, and a coupling of benthic diversity to surface productivity.

Nature↗

USGS2014

Herbivores and nutrients control grassland plant diversity via light limitation

Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

Nature↗