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At least 343 records · Page 19Linked to original sources
USGS2024

High-quality, chromosome-level reference genomes of the viviparous Caribbean skinks Spondylurus nitidus and S. culebrae

New World mabuyine skinks are a diverse radiation of morphologically cryptic lizards with unique reproductive biologies. Recent studies examining population-level data (morphological, ecological, and genomic) have uncovered novel biodiversity and phenotypes, including the description of dozens of new species and insights into the evolution of their highly complex placental structures. Beyond the potential for this diverse group to serve as a model for the evolution of viviparity in lizards, much of the taxonomic diversity is concentrated in regions experiencing increasing environmental instability from climate and anthropogenic change. Consequently, a better understanding of genome structure and diversity will be an important tool in the adaptive management and conservation of this group. Skinks endemic to Caribbean islands are particularly vulnerable to global change with several species already considered likely extinct and several remaining species either endangered or threatened. Combining PacBio long-read sequencing, Hi-C, and RNAseq data, here we present the first genomic resources for this group by describing new chromosome-level reference genomes for the Puerto Rican Skink Spondylurus nitidus and the Culebra Skink S. culebrae . Results indicate two high quality genomes, both ∼1.4 Gb, assembled nearly telomere to telomere with complete mitochondrion assembly and annotation.

Genome Biology and Evolution↗
USGS2011

The North American iron ore industry: A decade into the 21st century

During the 20th century, the iron ore mining industries of Canada and the United States passed through periods of transformation. The beginning of the 21st century has seen another period of transformation, with the failure of a number of steel companies and with consolidation of control within the North American iron ore industry. Canadian and United States iron ore production and the market control structure involved are changing rapidly. Consolidation of ownership, formation of foreign joint ventures, divestitures of upstream activities by steelmakers, and industry changes to ensure availability of feedstocks all played a role in recent developments in the North American iron ore industry. Canadian and U.S. iron ore operations and their strong linkage to downstream production, although isolated, must also be considered within the context of the changing global economy. Projects using new technology to produce direct reduced iron nuggets of 96-98% iron content and other projects designed to produce steel at minesites may once again change the face of the iron ore industry. Social and environmental issues related to sustainable development have had a significant effect on the North American iron ore industry.

Conference Paper↗
USGS2023

Patterns and controls of foliar nutrient stoichiometry and flexibility across United States forests

Plant element stoichiometry and stoichiometric flexibility strongly regulate ecosystem responses to global change. Here, we tested three potential mechanistic drivers (climate, soil nutrients, and plant taxonomy) of both using paired foliar and soil nutrient data from terrestrial forested National Ecological Observatory Network sites across the USA. We found that broad patterns of foliar nitrogen (N) and foliar phosphorus (P) are explained by different mechanisms. Plant taxonomy was an important control over all foliar nutrient stoichiometries and concentrations, especially foliar N, which was dominantly related to taxonomy and did not vary across climate or soil gradients. Despite a lack of site-level correlations between N and environment variables, foliar N exhibited intraspecific flexibility, with numerous species-specific correlations between foliar N and various environmental factors, demonstrating the variable spatial and temporal scales on which foliar chemistry and stoichiometric flexibility can manifest. In addition to plant taxonomy, foliar P and N:P ratios were also linked to soil nutrient status (extractable P) and climate, especially actual evapotranspiration rates. Our findings highlight the myriad factors that influence foliar chemistry and show that broad patterns cannot be explained by a single consistent mechanism. Furthermore, differing controls over foliar N versus P suggests that each may be sensitive to global change drivers on distinct spatial and temporal scales, potentially resulting in altered ecosystem N:P ratios that have implications for processes ranging from productivity to carbon sequestration.

Ecology↗
USGS2021

Global biotic events evident in the Paleogene marine strata of the eastern San Francisco Bay area, California

Paleogene marine strata in the eastern San Francisco Bay area are exposed in discontinuous outcrops in the various tectonic blocks. Although there are many missing intervals, the strata were previously thought to span most of the Paleocene and Eocene. Revision of biochronology and calibration to the international time scale as well as to the global oxygen isotope curve and sea-level curves indicate that the strata are latest Paleocene through middle Eocene in age and contain faunal changes that are linked to the overall global climate trends and hyperthermals of that time. The Paleocene-Eocene thermal maximum, third Eocene thermal maximum, early Eocene climatic optimum, and middle Eocene climatic optimum are all identified in the eastern San Francisco Bay marine strata. The dominance of smoothly finished, dissolution-resistant agglutinated benthic foraminiferal species corresponds with a rapid shoaling and rapid deepening (overcorrection) of the calcium compensation depth associated with the Paleocene-Eocene thermal maximum. The benthic foraminiferal extinction event was a dramatic turnover of benthic foraminiferal species that occurred shortly after the onset of the Paleocene-Eocene thermal maximum. Opportunistic species such as Bulimina , which indicate environmental stress and lower oxygen conditions, are commonly associated with the Paleocene-Eocene thermal maximum. Environmental changes similar to those observed during the Paleocene-Eocene thermal maximum also characterize the third Eocene thermal maximum, based on the agglutinated and opportunistic species. The early Eocene climatic optimum is noted by the presence of foraminiferal assemblages that indicate a stable, warmer water mass, abundant food, and an influx of terrigenous material. The onset and end of the middle Eocene climatic optimum are recognized by the dominance of siliceous microfossils. This research updates the age and environmental interpretations of the Paleogene formations occurring in the vicinity of Mount Diablo, eastern San Francisco Bay area. The revised interpretations, which are based on foraminifers and calcareous nannoplankton, make it possible to identify various global climatic and biotic events.

California↗
USGS2023

The Landscape Data Commons: A system for standardizing, accessing, and applying large environmental datasets for agroecosystem research and management

Understanding where, when, and why agroecosystems are changing requires quality information about ecosystems that span land tenure, ecological processes, and spatial scales. Over the past two decades, land management agencies and research groups have adopted a suite of standardized methods for monitoring rangelands, which have been implemented at over 85,000 monitoring locations globally. However, the ability to use these data to understand agroecosystem dynamics and change across scales and across land ownership has been limited because, until now, these data have not been available in a harmonized, accessible format for analyses, modeling, and decision-support tools. We present the Landscape Data Commons, a cyberinfrastructure platform that harmonizes and aggregates standardized agroecosystem data, enables linkages to models, and facilitates analysis and interpretation of data within decision-support tools. The Landscape Data Commons provides a community platform for users to contribute data and develop next-generation tools to support agroecosystem management through the 21st century.

Agricultural & Environmental Letters↗
USGS2017

Multidirectional abundance shifts among North American birds and the relative influence of multifaceted climate factors

Shifts in species distributions are major fingerprint of climate change. Examining changes in species abundance structures at a continental scale enables robust evaluation of climate change influences, but few studies have conducted these evaluations due to limited data and methodological constraints. In this study, we estimate temporal changes in abundance from North American Breeding Bird Survey data at the scale of physiographic strata to examine the relative influence of different components of climatic factors and evaluate the hypothesis that shifting species distributions are multidirectional in resident bird species in North America. We quantify the direction and velocity of the abundance shifts of 57 permanent resident birds over 44 years using a centroid analysis. For species with significant abundance shifts in the centroid analysis, we conduct a more intensive correlative analysis to identify climate components most strongly associated with composite change of abundance within strata. Our analysis focus on two contrasts: the relative importance of climate extremes vs. averages, and of temperature vs. precipitation in strength of association with abundance change. Our study shows that 36 species had significant abundance shifts over the study period. The average velocity of the centroid is 5.89 km·yr −1 . The shifted distance on average covers 259 km, 9% of range extent. Our results strongly suggest that the climate change fingerprint in studied avian distributions is multidirectional. Among 6 directions with significant abundance shifts, the northwestward shift was observed in the largest number of species ( n = 13). The temperature/average climate model consistently has greater predictive ability than the precipitation/extreme climate model in explaining strata‐level abundance change. Our study shows heterogeneous avian responses to recent environmental changes. It highlights needs for more species‐specific approaches to examine contributing factors to recent distributional changes and for comprehensive conservation planning for climate change adaptation.

Global Change Biology↗
USGS2022

Human populations in the world’s mountains: Spatio-temporal patterns and potential controls

Changing climate and human demographics in the world's mountains will have increasingly profound environmental and societal consequences across all elevations. Quantifying current human populations in and near mountains is crucial to ensure that any interventions in these complex social-ecological systems are appropriately resourced, and that valuable ecosystems are effectively protected. However, comprehensive and reproducible analyses on this subject are lacking. Here, we develop and implement an open workflow to quantify the sensitivity of mountain population estimates over recent decades, both globally and for several sets of relevant reporting regions, to alternative input dataset combinations. Relationships between mean population density and several potential environmental covariates are also explored across elevational bands within individual mountain regions (i.e. sub-mountain range scale). Globally, mountain population estimates vary greatly from 0.344 billion (<5% of the corresponding global total) to 2.289 billion (>31%) in 2015. A more detailed analysis using one of the population datasets (GHS-POP) revealed that in 35% of mountain sub-regions, population increased at least twofold over the 40-year period 19752015. The urban proportion of the total mountain population in 2015 ranged from 6% to 39%, depending on the combination of population and urban extent datasets used. At sub-mountain range scale, population density was found to be more strongly associated with climatic than with topographic and protected-area variables, and these relationships appear to have strengthened slightly over time. Such insights may contribute to improved predictions of future mountain population distributions under scenarios of future climatic and demographic change. Overall, our work emphasizes that irrespective of data choices, substantial human populations are likely to be directly affected by and themselves affect mountainous environmental and ecological change. It thereby further underlines the urgency with which the multitudinous challenges concerning the interactions between mountain climate and human societies under change must be tackled.

PLoS ONE↗
USGS2009

The ecology of dust

Wind erosion and associated dust emissions play a fundamental role in many ecological processes and provide important biogeochemical connectivity at scales ranging from individual plants up to the entire globe. Yet, most ecological studies do not explicitly consider dust‐driven processes, perhaps because most relevant research on aeolian (wind‐driven) processes has been presented in a geosciences rather than an ecological context. To bridge this disciplinary gap, we provide a general overview of the ecological importance of dust, examine complex interactions between wind erosion and ecosystem dynamics from the scale of plants and surrounding space to regional and global scales, and highlight specific examples of how disturbance affects these interactions and their consequences. It is likely that changes in climate and intensification of land use will lead to increased dust production from many drylands. To address these issues, environmental scientists, land managers, and policy makers need to consider wind erosion and dust emissions more explicitly in resource management decisions.

Frontiers in Ecology and the Environment↗
USGS2015

Are conservation organizations configured for effective adaptation to global change?

Conservation organizations must adapt to respond to the ecological impacts of global change. Numerous changes to conservation actions (eg facilitated ecological transitions, managed relocations, or increased corridor development) have been recommended, but some institutional restructuring within organizations may also be needed. Here we discuss the capacity of conservation organizations to adapt to changing environmental conditions, focusing primarily on public agencies and nonprofits active in land protection and management in the US. After first reviewing how these organizations anticipate and detect impacts affecting target species and ecosystems, we then discuss whether they are sufficiently flexible to prepare and respond by reallocating funding, staff, or other resources. We raise new hypotheses about how the configuration of different organizations enables them to protect particular conservation targets and manage for particular biophysical changes that require coordinated management actions over different spatial and temporal scales. Finally, we provide a discussion resource to help conservation organizations assess their capacity to adapt.

Frontiers in Ecology and the Environment↗
USGS2013

Global change and water availability and quality: Challenges ahead

The US is in the midst of a continental scale, multiyear water resources experiment. What are we doing? We are expanding population at two to three times the national growth rate, particularly where water stress is already great. We are expanding irrigated agriculture from the west to the east, where increased competition for water has urban, agricultural, and environmental interests at odds, and increasingly, in court. This experiment and related challenges will continue and likely intensify as nonclimatic and climatic factors, such as predicted rising temperature and changes in the distribution of precipitation in time and space, continue to develop.

Book chapter↗
USGS2022

Harnessing island–ocean connections to maximize marine benefits of island conservation

Islands support unique plants, animals, and human societies found nowhere else on the Earth. Local and global stressors threaten the persistence of island ecosystems, with invasive species being among the most damaging, yet solvable, stressors. While the threat of invasive terrestrial mammals on island flora and fauna is well recognized, recent studies have begun to illustrate their extended and destructive impacts on adjacent marine environments. Eradication of invasive mammals and restoration of native biota are promising tools to address both island and ocean management goals. The magnitude of the marine benefits of island restoration, however, is unlikely to be consistent across the globe. We propose a list of six environmental characteristics most likely to affect the strength of land–sea linkages: precipitation, elevation, vegetation cover, soil hydrology, oceanographic productivity, and wave energy. Global databases allow for the calculation of comparable metrics describing each environmental character across islands. Such metrics can be used today to evaluate relative potential for coupled land–sea conservation efforts and, with sustained investment in monitoring on land and sea, can be used in the future to refine science-based planning tools for integrated land–sea management. As conservation practitioners work to address the effects of climate change, ocean stressors, and biodiversity crises, it is essential that we maximize returns from our management investments. Linking efforts on land, including eradication of island invasive mammals, with marine restoration and protection should offer multiplied benefits to achieve concurrent global conservation goals.

PNAS↗
USGS2011

Are there pre-Quaternary geological analogues for a future greenhouse warming?

Given the inherent uncertainties in predicting how climate and environments will respond to anthropogenic emissions of greenhouse gases, it would be beneficial to society if science could identify geological analogues to the human race’s current grand climate experiment . This has been a focus of the geological and palaeoclimate communities over the last 30 years, with many scientific papers claiming that intervals in Earth history can be used as an analogue for future climate change. Using a coupled ocean–atmosphere modelling approach, we test this assertion for the most probable pre-Quaternary candidates of the last 100 million years: the Mid- and Late Cretaceous, the Palaeocene–Eocene Thermal Maximum (PETM), the Early Eocene, as well as warm intervals within the Miocene and Pliocene epochs. These intervals fail as true direct analogues since they either represent equilibrium climate states to a long-term CO 2 forcing—whereas anthropogenic emissions of greenhouse gases provide a progressive (transient) forcing on climate—or the sensitivity of the climate system itself to CO 2 was different. While no close geological analogue exists, past warm intervals in Earth history provide a unique opportunity to investigate processes that operated during warm (high CO 2 ) climate states. Palaeoclimate and environmental reconstruction/modelling are facilitating the assessment and calculation of the response of global temperatures to increasing CO 2 concentrations in the longer term (multiple centuries); this is now referred to as the Earth System Sensitivity, which is critical in identifying CO 2 thresholds in the atmosphere that must not be crossed to avoid dangerous levels of climate change in the long term. Palaeoclimatology also provides a unique and independent way to evaluate the qualities of climate and Earth system models used to predict future climate.

Philosophical Transactions of the Royal Society A:↗
USGS2006

The USGS Land Cover Institute

The U.S. Geological Survey (USGS) Land Cover Institute (LCI) is located at the Center for Earth Resources Observation and Science (EROS) in Sioux Falls, South Dakota. It provides a focal point for advancing USGS land cover studies and applications. Satellite images and other remotely sensed data play an important role in this research. Land Cover scientists investigate new ways to use satellite images and other data to map land cover. They assess national and global land cover characteristics and monitor how - and how rapidly - land cover changes. They also study the economic impacts of land cover as well as its effects on water quality, the spread of invasive species, habitats and biodiversity, climate variability, and other environmental factors.

Fact Sheet↗
USGS2025

Seasonal increases in global dryland gross primary production are modulated by root soil moisture and temperature

Dryland ecosystems, which are highly sensitive to environmental variability across space and through time, play a critical role in the global carbon cycle. To understand the carbon sink role of drylands, this study used different sources of global dryland gross primary productivity (GPP) and evaluated the spatiotemporal variations in seasonal GPP in response to climatic and soil water conditions from 1982 to 2018. Root-zone soil moisture consistently exerted a predominant positive influence on dryland GPP across all seasons, while the effect of surface soil moisture was less influential. Maximum temperature (Tmax) ranked as the second most influential factor on GPP, switching from a notable positive effect during cooler seasons to a negative impact during warmer seasons. Similarly, during cool seasons, vapor pressure deficit exhibited a notable positive effect on GPP, but this influence became negative in warmer seasons. Tmax indirectly regulated GPP by modulating the influence of other meteorological factors. During the warm season, Tmax negatively affected GPP via VPD, while in the cold season, it positively affected GPP through VPD. This study explicitly identifies the pivotal role of root-zone soil moisture in determining GPP and highlights the substantial seasonal differences and regulatory role of temperature in how other environmental variables influence GPP. These findings provide a novel perspective for understanding the responses of dryland ecosystems to climate change.

Global and Planetary Change↗
USGS2025

The diel niche of brown bears: Constraints on adaptive capacity in human-modified landscapes

D Diel activity rhythms, representing the behavioral pattern of the sleep–wake cycle, may be adjusted by wildlife in response to changes in environmental conditions. An increase in nocturnality is typically recognized as an adaptive strategy to segregate from humans and mitigate heat stress. Numerous studies have investigated spatial patterns and habitat use of large carnivores in human-modified landscapes, but little research has examined their activity rhythms. We compiled Global Positioning System data (2004–2022) for 139 brown bears Ursus arctos from six populations across Europe, representing a human-modified landscape, and the Greater Yellowstone Ecosystem, U.S.A., representing a landscape with limited human impact, which we used to calculate hourly movement rates as an activity proxy. Using a Bayesian approach to model the temporal autocorrelation of activity data, we tested if the extent of nocturnality in brown bears is modulated by intensity of human encroachment, accounting for primary productivity and maximum ambient temperature. All bear populations exhibited a predominantly bimodal, crepuscular pattern of activity, although Yellowstone bears were proportionally more crepuscular and diurnal. Whereas the effect of primary productivity was variable, all European populations became more nocturnal in response to higher human encroachment and reduced diurnal and crepuscular activity at higher summer temperatures, decreasing overall diel activity levels. Yellowstone bears displayed the greatest shift towards nocturnality among all populations in response to increasing human encroachment, and increased nocturnal activity to compensate for lower diurnal and crepuscular activity at higher summer temperatures. Our research indicates that European bears in human-modified landscapes may be reaching a limit in the behavioral plasticity they can manifest in their activity patterns, being already constrained into increased nocturnality. Our findings enhance the understanding of brown bear adaptive capacity to accommodate future changes, such as urbanization and increasing temperatures, to the ecosystems they inhabit.

Ecography↗
USGS2013

Roles of patch characteristics, drought frequency, and restoration in long-term trends of a widespread amphibian

Despite the high profile of amphibian declines and the increasing threat of drought and fragmentation to aquatic ecosystems, few studies have examined long-term rates of change for a single species across a large geographic area. We analyzed growth in annual egg-mass counts of the Columbia spotted frog (Rana luteiventris) across the northwestern United States, an area encompassing 3 genetic clades. On the basis of data collected by multiple partners from 98 water bodies between 1991 and 2011, we used state-space and linear-regression models to measure effects of patch characteristics, frequency of summer drought, and wetland restoration on population growth. Abundance increased in the 2 clades with greatest decline history, but declined where populations are considered most secure. Population growth was negatively associated with temporary hydroperiods and landscape modification (measured by the human footprint index), but was similar in modified and natural water bodies. The effect of drought was mediated by the size of the water body: populations in large water bodies maintained positive growth despite drought, whereas drought magnified declines in small water bodies. Rapid growth in restored wetlands in areas of historical population declines provided strong evidence of successful management. Our results highlight the importance of maintaining large areas of habitat and underscore the greater vulnerability of small areas of habitat to environmental stochasticity. Similar long-term growth rates in modified and natural water bodies and rapid, positive responses to restoration suggest pond construction and other forms of management can effectively increase population growth. These tools are likely to become increasingly important to mitigate effects of increased drought expected from global climate change.

Conservation Biology↗
USGS2025

Greater white-fronted goose habitat use in Louisiana provides water depth management insights

Numerous waterfowl species have altered their geographic distribution in recent decades. The greater white-fronted goose ( Anser albifrons ) has shifted its wintering distribution from coastal marshes in Texas and Louisiana, USA, to interior landscapes, creating challenges for conservation managers. Although the range shift has been primarily attributed to landscape-scale changes in rice production, effects of fine-scale habitat conditions on greater white-fronted goose habitat use are unknown. Thus, information on fine-scale environmental conditions could provide information to managers working to mitigate effects of the shift. We used global positioning system neck collars to monitor 78 greater white-fronted geese in Louisiana each winter during 2016–2019 and visited all used locations to record vegetation height, water depth, and land cover. We modeled greater white-fronted goose habitat use in 4 regions across Louisiana (central, coastal, north, southwest), and evaluated effects of vegetation height, water depth, land cover, and interactions. In our candidate model set, we included a sampling null, which accounted for differences in sampling frequencies among hunt seasons and diel periods. The top model in the central, coastal, and north regions included water depth, whereas the top model in the southwest region included water depth, vegetation height, and land cover. Parameter estimates and confidence intervals indicated that goose habitat use was higher at sites with >5.1 cm of water compared to dry sites or sites with <5.1 cm of water. In the southwest region, goose habitat use was highest in areas identified as other land cover (e.g., corn, cotton, rye, sugarcane) and lowest in open water. Although Louisiana has substantial anthropogenic food resources in the form of rice agriculture and abundant grazing opportunities afforded by mild winters, our results indicate that wet areas provide better habitat to greater white-fronted geese than dry areas. New agricultural flooding regimes in Louisiana could improve habitat quality and potentially mitigate some effects of the winter distribution shift.

Louisiana↗