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At least 703 records · Page 39Linked to original sources
USGS2008

Florida Integrated Science Center (FISC) Coral Reef Research

Coral reefs provide important ecosystem services such as shoreline protection and the support of lucrative industries including fisheries and tourism. Such ecosystem services are being compromised as reefs decline due to coral disease, climate change, overfishing, and pollution. There is a need for focused, integrated science to understand the complex ecological interactions and effects of these many stressors and to provide information that will effectively guide policies and best management practices to preserve and restore these important resources. The U.S. Geological Survey Florida Integrated Science Center (USGS-FISC) is conducting a coordinated Coral Reef Research Project beginning in 2009. Specific research topics are aimed at addressing priorities identified in the 'Strategic Science for Coral Ecosystems 2007-2011' document (U.S. Geological Survey, 2007). Planned research will include a blend of historical, monitoring, and process studies aimed at improving our understanding of the development, current status and function, and likely future changes in coral ecosystems. Topics such as habitat characterization and distribution, coral disease, and trends in biogenic calcification are major themes of understanding reef structure, ecological integrity, and responses to global change.

Fact Sheet↗
USGS2019

Optimizing historic preservation under climate change: Decision support for cultural resource adaptation planning in national parks

Climate change poses great challenges for cultural resource management, particularly in coastal areas. Cultural resources, such as historic buildings, in coastal areas are vulnerable to climate impacts including inundation, deterioration , and destruction from sea-level rise and storm-related flooding and erosion. However, research that assesses the trade-offs between actions for protecting vulnerable and valuable cultural resources under budgetary constraints is limited. This study focused on developing a decision support model for managing historic buildings at Cape Lookout National Seashore. We designed the Optimal Preservation Decision Support (OptiPres) model to: (a) identify optimal, annual adaptation actions for historic buildings across a 30-year planning horizon, (b) quantify trade-offs between different actions and the timing of adaptation actions under constrained budgets, and (c) estimate the effectiveness of budget allocations on the resource value of historic buildings. Our analysis of the model suggests that: (1) funding allocation thresholds may exist for national parks to maintain the historical significance and use potential of historic buildings under climate change, (2) the quantitative assessment of trade-offs among alternative adaptation actions provides generalizable guidance for decision makers about the dynamics of their managed system, and (3) the OptiPres model can identify cost-efficient approaches to allocate funding to maintain the historical value of buildings vulnerable to the effects of climate change. Therefore, the OptiPres model, while not designed as a prescriptive decision tool, allows managers to understand the consequences of proposed adaptation actions. The OptiPres model can guide park managers to make cost-effective climate adaptation decisions for historic buildings more transparently and robustly.

Land Use Policy↗
USGS2000

USGS research on three mid-latitude glaciers

Low- and mid-latitude regions of the earth are home to 80 to 90 percent of the world's population. Because of this, the U.S. Geological Survey (USGS) is conducting a research program to study the geochemistry of precipitation, snow, ice, and runoff samples from mid-latitude glaciers in Kyrghyzstan, Nepal, and the United States, Areas of research, such as ground-water studies, reconstructing paleoclimate records, describing anthropogenic input of chemicals to the environment, and modeling global climate, are important to the well being of the worlds' population and can be supplemented by the collection and chemical analysis of snow and ice cores. Nearly all the constituents that compose snow and ice-core samples contribute vital information, whether it be the microbial communities that flourish in snow, radionuclides present in various amounts in all the samples, or location-specific deposits of mercury and nitrate. This work is hastened by the fact that mid-latitude glaciers, and the information preserved in them, are rapidly disappearing as a result of global warming. Research collaboration for this project includes 12 national and 7 international universities, and 4 government agencies. Funding is provided by the National Science Foundation, the U.S. Department of Energy, and the USGS.

Conference Paper↗
USGS2012

Assessment of boreal forest historical C dynamics in the Yukon River Basin: relative roles of warming and fire regime change

Carbon (C) dynamics of boreal forest ecosystems have substantial implications for efforts to mitigate the rise of atmospheric CO 2 and may be substantially influenced by warming and changing wildfire regimes. In this study we applied a large-scale ecosystem model that included dynamics of organic soil horizons and soil organic matter characteristics of multiple pools to assess forest C stock changes of the Yukon River Basin (YRB) in Alaska, USA, and Canada from 1960 through 2006, a period characterized by substantial climate warming and increases in wildfire. The model was calibrated for major forests with data from long-term research sites and evaluated using a forest inventory database. The regional assessment indicates that forest vegetation C storage increased by 46 Tg C, but that total soil C storage did not change appreciably during this period. However, further analysis suggests that C has been continuously lost from the mineral soil horizon since warming began in the 1970s, but has increased in the amorphous organic soil horizon. Based on a factorial experiment, soil C stocks would have increased by 158 Tg C if the YRB had not undergone warming and changes in fire regime. The analysis also identified that warming and changes in fire regime were approximately equivalent in their effects on soil C storage, and interactions between these two suggests that the loss of organic horizon thickness associated with increases in wildfire made deeper soil C stocks more vulnerable to loss via decomposition. Subbasin analyses indicate that C stock changes were primarily sensitive to the fraction of burned forest area within each subbasin and that boreal forest ecosystems in the YRB are currently transitioning from being sinks to sources at ∼0.7% annual area burned. We conclude that it is important for international mitigation efforts focused on controlling atmospheric CO 2 to consider how climate warming and changes in fire regime may concurrently affect the CO 2 sink strength of boreal forests. It is also important for large-scale biogeochemical and earth system models to include organic soil dynamics in applications to assess regional C dynamics of boreal forests responding to warming and changes in fire regime.

Ecological Applications↗
USGS2020

Restoration at the landscape scale as a means of mitigation and adaptation to climate change

Purpose of Review Although landscape-scale restoration efforts are gaining traction worldwide, their success is generally unknown. We review landscape-scale restorations to gain insight to whether focal ecological outcomes have been achieved, in the face of changing environmental conditions. Recent Findings Only 9% of the 477 articles that resulted from our search were studies of landscape-scale restorations. The majority (73%) of the landscape restorations from our study have occurred since the 1990s, indicating that this type of restoration has gained in popularity in the last 30 years. Furthermore, 67% of these restoration studies occurred in a single country: China. Many scientific studies have addressed the ability of a species to shift ranges with climate change, yet few of the landscape-scale restoration studies used for our study addressed this question. Instead, 87% of the studies focused on ecosystem function, rather than community-level processes, as a result of restoration. Summary There is a clear need for more research to be undertaken on the ecological outcomes of landscape-scale restorations to understand whether they enable species and communities to shift their ranges or adapt to climate change. Conservation practitioners could utilize our decision matrix as a tool to guide restoration of individual sites within a landscape context, as well as current and future climatic conditions, to guide ecological outcomes of interest. Optimal biodiversity maintenance requires habitat conservation in concert with restoration activities at the landscape scale, and the latter, likely increasingly so in a world of changing climate.

Current Landscape Ecology Reports↗
USGS2024

2023-2024 Coastal sage scrub and chaparral community monitoring for western San Diego County

Western San Diego County is dominated by shrublands supporting biologically diverse native plant and animal communities. Widespread urbanization has led to regional habitat loss and fragmentation, and many species in these shrubland communities are rare, threatened, or endangered. Large-scale, multiple-species conservation planning has resulted in a regional preserve system that focuses on these shrubland communities. Several large-scale threats are leading to type conversion from shrub-dominated to non-native invasive annual grass-dominated vegetation. To understand the changes that are occurring to native shrublands, we have developed a vegetation monitoring program with several components at multiple spatial scales, focused on quantifying coastal sage scrub (CSS) and chaparral vegetation community characteristics. Several drivers of change associated with type conversion of native shrubland to non-native annual grassland have been identified by previous research including increasing fire frequency, nitrogen deposition from air pollution, and prolonged and intense drought associated with changing climate. Loss of ecological integrity indices have been proposed as useful measures of the threat of degradation and type conversion of shrublands in San Diego County. For this study, ecological integrity is defined as a system’s ability to maintain species’ relationships and functions comparable to natural habitat in the region. Previous studies have identified the percent cover of invasive non-native annual grasses as a proxy for overall ecological degradation (loss of integrity) that is consistent across native taxonomic groups. Increased cover of non-native grass is associated with lower integrity of the shrubland vegetation community as shrub-associated plant and animal species are replaced by species preferring grassy and disturbed habitats. The objectives of this CSS and chaparral vegetation community monitoring plan are to: 1) Determine the distribution, composition, structure, and integrity of CSS and chaparral vegetation communities on conserved lands in western San Diego County, 2) Identify whether these attributes of the vegetation communities are changing over time, and 3) Evaluate relationships of known drivers of change (threats) and environmental factors in association with changes in vegetation community attributes. The CSS and chaparral vegetation community monitoring program is divided into four components: 1) vegetation mapping, 2) GIS/remote sensing office analysis of landscape-scale data, 3) permanent field plots using Unmanned Aerial Systems (UAS) and field data collections, and 4) animal and target species surveys and rapid assessment protocols. The first component, which is not detailed in this vegetation monitoring plan, aims to map vegetation communities every 10-15 years based on a classification developed for western San Diego County. High resolution aerial imagery will be used to update the 2012 vegetation map and expand it across the entire study area. The second component uses remote sensing models to annually track ecological integrity of shrublands across the study area and will include a map of areas of change and areas of stability over several decades. These landscape-scale integrity classifications will be used to analyze ecological processes, threats, and abiotic factors relative to changes to shrubland ecological integrity over time and space. The third component includes field surveys of 100 permanent plots across areas historically mapped as shrublands. Surveys in the 1930s mapped vegetation types using plot data. By using this historical classification map, we included areas that have already type-converted from shrubland to non-native annual grassland. The plots were split between CSS (55 plots) and chaparral (45 plots) and stratified into four geographical eco-subregions to guarantee coverage over small patches of habitat along the heavily developed coast. Surveys will include the collection of UAS imagery at a very high resolution. Species-level identifications will be made from the imagery based on a plant list compiled of all species detected in the plot during a thorough field survey by botanists, combined with geo-referenced samples of plant species locations. In addition, herbaceous cover will be estimated in the field using nine 1-m diameter circles (one per subplot) to obtain ocular estimates of cover for each plant species within the circle frame. Soil samples will be collected and analyzed for important element compositions. These data will be analyzed to evaluate plot-level ecological integrity based on species composition and cover. Repeated monitoring will allow evaluation of changes in vegetation attributes over time with known drivers or threats and other environmental factors. In addition, analyses will focus on indicator species and various measures of biological diversity for the vegetation communities. Finally, animal species and rare plants will be assessed using either taxa-based rapid assessment protocols or specialized species-specific protocols for rarer species. The purpose of these assessments is to document the status, habitat, and threat covariates of specific species and confirm the species composition and diversity of animal taxonomic groups (e.g., pollinators). Diversity and abundance of animal species at vegetation plots will be used to refine measures and thresholds of ecological integrity. Rapid assessment protocols for animal taxonomic groups can include multiple detection methods such as, camera traps, cover boards, and bird point counts. Pollinators will be monitored at plots using a protocol currently being developed in conjunction with but separately from this plan. Target rare plant species will be monitored using the regional Inspect and Manage (IMG) protocol that measures the status of rare plant occurrences and habitat and threat covariates over time. Species-specific animal survey methods will be refined as these species are prioritized for future monitoring. The goal of this monitoring program is to classify CSS and chaparral vegetation community integrity, identify areas of degradation across western San Diego County, and characterize drivers, and environmental factors associated with loss of ecological integrity. A combination of vegetation mapping, landscape-scale remote sensing, and field plots will be used to address all the aspects of our research questions. Data compiled and collected will be available to conservation partners to help inform future management decisions.

California↗
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↗
USGS2021

A multiproxy database of western North American Holocene paleoclimate records

Holocene climate reconstructions are useful for understanding the diverse features and spatial heterogeneity of past and future climate change. Here we present a database of western North American Holocene paleoclimate records. The database gathers paleoclimate time series from 184 terrestrial and marine sites, including 381 individual proxy records. The records span at least 4000 of the last 12 000 years (median duration of 10 725 years) and have been screened for resolution, chronologic control, and climate sensitivity. Records were included that reflect temperature, hydroclimate, or circulation features. The database is shared in the machine readable Linked Paleo Data (LiPD) format and includes geochronologic data for generating site-level time-uncertain ensembles. This publicly accessible and curated collection of proxy paleoclimate records will have wide research applications, including, for example, investigations of the primary features of ocean–atmospheric circulation along the eastern margin of the North Pacific and the latitudinal response of climate to orbital changes. The database is available for download at https://doi.org/10.6084/m9.figshare.12863843.v1 (Routson and McKay, 2020).

Earth System Science Data↗
USGS2015

Internships, employment opportunities, and research grants

As an unbiased, multidisciplinary science organization, the U.S. Geological Survey (USGS) is dedicated to the timely, relevant, and impartial study of the health of our ecosystems and environment, our natural resources, the impacts of climate and land-use change, and the natural hazards that threaten us. Opportunities for undergraduate and graduate students and faculty to participate in USGS science are available in the selected programs described below. Please note: U.S. citizenship is required for all government positions. This publication has been superseded by USGS General Information Product 165 Grant Opportunities for Academic Research and Training and USGS General Information Product 166 Student and Recent Graduate Employment Opportunities . This publication is proceeded by USGS General Information Product 80 Internships, Employment Opportunities, and Research Grants published in 2008.

General Information Product↗
USGS2018

The Polar WRF downscaled historical and projected twenty-first century climate for the coast and foothills of Arctic Alaska

Climate change is most pronounced in the northern high latitude region. Yet, climate observations are unable to fully capture regional-scale dynamics due to the sparse weather station coverage, which limits our ability to make reliable climate-based assessments. A set of simulated data products was therefore developed for the North Slope of Alaska through a dynamical downscaling approach. The polar-optimized Weather Research and Forecast (Polar WRF) model was forced by three sources: The ERA-interim reanalysis data (for 1979–2014), the Community Earth System Model 1.0 (CESM1.0) historical simulation (for 1950–2005), and the CESM1.0 projected (for 2006–2100) simulations in two Representative Concentration Pathways (RCP4.5 and RCP8.5) scenarios. Climatic variables were produced in a 10-km grid spacing and a 3-h interval. The ERA-interim forced WRF (ERA-WRF) proves the value of dynamical downscaling, which yields more realistic topographical-induced precipitation and air temperature, as well as corrects underestimations in observed precipitation. In summary, dry and cold biases to the north of the Brooks Range are presented in ERA-WRF, while CESM forced WRF (CESM-WRF) holds wet and warm biases in its historical period. A linear scaling method allowed for an adjustment of the biases, while keeping the majority of the variability and extreme values of modeled precipitation and air temperature. CESM-WRF under RCP 4.5 scenario projects smaller increase in precipitation and air temperature than observed in the historical CESM-WRF product, while the CESM-WRF under RCP 8.5 scenario shows larger changes. The fine spatial and temporal resolution, long temporal coverage, and multi-scenario projections jointly make the dataset appropriate to address a myriad of physical and biological changes occurring on the North Slope of Alaska.

Alaska↗
USGS2014

Trends in conservation research and management in Hawai‘i over the past 20 years

Hawaiʻi, an archipelago of the most isolated inhabited islands on the planet, faces unique and extreme challenges to its biodiversity. We examined how the conservation community has responded to these challenges and how the responses have changed over time, using twenty years of abstracts from the Hawaiʻi Conservation Conference, a yearly gathering of the majority of scientists, managers and the public in Hawaiʻi. Of the 2145 abstracts considered, 60% percent reported research results; 40.0% reported information on conservation and resource management programmes and institutions (i.e., non-research abstracts). Initially, applied research abstracts predominated, but in recent years the number of basic research abstracts has become similar. Across taxonomic groups, terrestrial plants, mammals and birds were the dominant research subjects, fish, algae and fungi were noticeably less studied relative to their diversity in Hawaiʻi. Bird and fish species studied were mostly native; research on most other taxa was evenly divided between native and non-native species. Topics have oscillated in frequency over the years, but there have been no dramatic trends, with the exception of climate change and Local Ecological Knowledge (LEK). Although there is an increasing trend in LEK and cross-disciplinary studies, the number of related abstracts have remained uncommon through the period, accounting for less than 5.0% of total research abstracts analyzed. Our results offer an oportunity for the conservation community to take a closer look at reported effort to better address key conservation questions for Hawaiʻi.

Hawaiʻi↗
USGS2007

Antarctica: A Keystone in a Changing World--Online Proceedings for the Tenth International Symposium on Antarctic Earth Sciences. Santa Barbara, California, U.S.A.--August 26 to September 1, 2007

Overview: The International Symposium on Antarctic Earth Sciences (ISAES) is held once every four years to provide an international forum for presenting research results and new ideas and for planning future Antarctic geoscience research projects. This Tenth ISAES coincides with the International Polar Year (IPY; 50th Anniversary of the International Geophysical Year) and has been structured to showcase the great breadth of geoscience research being done in Antarctic regions by more than more than 100 institutions located in over 30 countries. The science program of the Symposium encompasses six broad themes that cover key topics on evolution and interactions of the geosphere, cryosphere and biosphere and their cross-linkages with past and historic paleoclimates. Emphasis is also on deciphering the climate records in ice cores, geologic cores, rock outcrops and those inferred from climate models. New technologies for the coming decades of geoscience data collection are also highlighted. Ten keynote presentations at the symposium outline the foundation for the research sessions of the symposium and the structure of the Online Proceedings and Proceedings Book for the Tenth ISAES. The ISAES is traditionally a cornerstone meeting for the Scientific Committee on Antarctic Research (SCAR). In recognition of the Tenth ISAES being held in the U.S. for the first time in 30 years and during IPY, the publication of the symposium proceedings is being handled as a special collaborative effort of the U.S. National Science Foundation, the U.S. Geological Survey, The National Academies Polar Research Board and The National Academies Press. The National Academies Polar Research Board oversees the activities of SCAR in the U.S. Special attention has been directed at publication formats for the symposium, to expedite the open and wide sharing of mature and preliminary research results presented in talks and posters at the Tenth ISAES. All symposium presentations are documented by a short Summary printed in the Symposium Program Booklet and either a short research paper or an extended abstract. The research papers and extended abstracts are compiled in this Online Proceedings and are replicated on a DVD-ROM that is placed in the back of the Tenth ISAES Proceedings Book. The Proceedings Book has printed versions of the keynote talks and an overview paper of the symposium. The short research papers and extended abstracts have been handled differently. Research papers present mature research results and syntheses. They have been peer-reviewed using standard journal procedures. Following revisions and acceptances by co-editors, the papers have been formatted for publication and proofread by authors. Each paper has been assigned a Digital Object Identification (DOI) number and separate html link, and posted online (as part of this USGS Open-File Report series) to ensure open and wide access to the research results. Extended abstracts focus on preliminary research results and have not been peer reviewed. They have had only minimal editorial review and revision. Authors have formatted and proofread their papers. Extended abstracts were not given DOI numbers and are included together in a separate chapter of this online Proceedings. USGS publications staff and Stanford-student editorial assistants indexed and compiled the PDF versions of the short research papers and extended abstracts for inclusion in this online Proceedings. USGS staff created the master DVD-ROM that contains a replica of the Online Proceedings for the Tenth ISAES, and provided the DVD-ROM copies that are included in the Tenth ISAES Proceedings Book published by The National Academies Press in the U.S. A team of more than 25 co-editors coordinated with the numerous authors and peer reviewers in handling the many research papers and extended abstracts that are included herein. Handling the large volume of short papers and extended abstracts, getting most of them onli

Open-File Report↗
USGS2017

Can beaches survive climate change?

Anthropogenic climate change is driving sea level rise, leading to numerous impacts on the coastal zone, such as increased coastal flooding, beach erosion, cliff failure, saltwater intrusion in aquifers, and groundwater inundation. Many beaches around the world are currently experiencing chronic erosion as a result of gradual, present-day rates of sea level rise (about 3 mm/year) and human-driven restrictions in sand supply (e.g., harbor dredging and river damming). Accelerated sea level rise threatens to worsen coastal erosion and challenge the very existence of natural beaches throughout the world. Understanding and predicting the rates of sea level rise and coastal erosion depends on integrating data on natural systems with computer simulations. Although many computer modeling approaches are available to simulate shoreline change, few are capable of making reliable long-term predictions needed for full adaption or to enhance resilience. Recent advancements have allowed convincing decadal to centennial-scale predictions of shoreline evolution. For example, along 500 km of the Southern California coast, a new model featuring data assimilation predicts that up to 67% of beaches may completely erode by 2100 without large-scale human interventions. In spite of recent advancements, coastal evolution models must continue to improve in their theoretical framework, quantification of accuracy and uncertainty, computational efficiency, predictive capability, and integration with observed data, in order to meet the scientific and engineering challenges produced by a changing climate.

Journal of Geophysical Research F: Earth Surface↗
USGS1995

The interaction of groundwater with prairie pothole wetlands in the Cottonwood Lake area, east-central North Dakota 1979-1990

The interaction of ground water with prairie wetlands in the Cottonwood Lake area has been the focus of research by the U.S. Geological Survey and the U.S. Fish and Wildlife Service since 1977. During this time, climatic conditions at the site ranged from near the driest to near the wettest of the century. Water levels in wetlands and in water-table wells throughout the study area responded to these changing climate conditions in a variety of ways. The topographically highest wetlands recharged ground water whenever they received water from precipitation. The wetland of principal interest, Wetland P1, which is at an intermediate altitude, received ground-water discharge much of the time, but it also had transpiration-induced seepage from it along parts of its perimeter during all but the wettest year. The large fluctuations of the water table in response to recharge and transpiration reflect the ease with which water moves vertically through the fractured till. Lateral movement of ground water is much slower; pore-water moves vertically through the fractured till. Lateral movement of ground water is much slower; pore-water velocities are generally less than 3 m yr −1 . The water supply to the wetlands is largely from precipitation during fall, winter, and spring. During these periods, precipitation either falls directly on the wetland, or precipitation that falls on the upland runs over frozen soils or saturated soils into the wetland. The average ratio of stage rise to total overwinter precipitation was 2.59 for the 12-year study period. After plants leaf out, precipitation generally results in much lower rises of the wetland water level. The average ratio of stage rise to over-summer precipitation was less than 1.0.

North Dakota↗
USGS1989

Changes in floral diversities, floral turnover rates, and climates in Campanian and Maastrichtian time, North Slope of Alaska

One-hundred-and-ten angiosperm pollen taxa have been found in upper Campanian to Masstrichtian rocks of the Colville River region, North Slope of Alaska. These are the highest paleolatitude Campanian and Maastrichtian floras known from North America. Total angiosperm pollen diversity rose during the Campanian and declined toward the end of the Maastrichtian. However, anemophilous porate pollen of the Betulaceae-Myricaceae-Ulmaceae complex increased gradually in diversity during the late Campanian and Maastrichtian and into the Paleocene. Turnover of angiosperm taxa was active throughout most of late Campanian and Maastrichtian time; rapid turnover affected mainly the taxa of zoophilous herbs, representing an bundant but ecologically subordinate element of the vegetation. Last appearances of pollen taxa during the late Campanian and Maastrichtian probably represented mainly extinctions rather than emigrations; end- Cretaceous angiosperm extinctions in the North American Arctic began well before the Cretaceous-Tertiary boundary event. The last appearances in the late Maastrichtian took place in bursts; they appear to represent stepwise rather than gradual events, which may indicate the existence of pulses of climatic change particularly in late Maastrichtian time. ?? 1989.

Alaska↗
USGS2018

Stream fish colonization but not persistence varies regionally across a large North American river basin

Many species have distributions that span distinctly different physiographic regions, and effective conservation of such taxa will require a full accounting of all factors that potentially influence populations. Ecologists recognize effects of physiographic differences in topography, geology and climate on local habitat configurations, and thus the relevance of landscape heterogeneity to species distributions and abundances. However, research is lacking that examines how physiography affects the processes underlying metapopulation dynamics. We used data describing occupancy dynamics of stream fishes to evaluate evidence that physiography influences rates at which individual taxa persist in or colonize stream reaches under different flow conditions. Using periodic survey data from a stream fish assemblage in a large river basin that encompasses multiple physiographic regions, we fit multi-species dynamic occupancy models. Our modeling results suggested that stream fish colonization but not persistence was strongly governed by physiography, with estimated colonization rates considerably higher in Coastal Plain streams than in Piedmont and Blue Ridge systems. Like colonization, persistence was positively related to an index of stream flow magnitude, but the relationship between flow and persistence did not depend on physiography. Understanding the relative importance of colonization and persistence, and how one or both processes may change across the landscape, is critical information for the conservation of broadly distributed taxa, and conservation strategies explicitly accounting for spatial variation in these processes are likely to be more successful for such taxa.

Alabama, Florida, Georgia↗
USGS2020

A spatial analysis of climate gentrification in Orleans Parish, Louisiana post-Hurricane Katrina

Background Hurricane Katrina made landfall in New Orleans, Louisiana as a Category 3 storm in August 2005. Storm surges, levee failures, and the low-lying nature of New Orleans led to widespread flooding, damage to over 70% of occupied housing, and evacuation of 80–90% of city residents. Only 57% of the city's black population has returned. Many residents complain of gentrification following rebuilding efforts. Climate gentrification is a recently described phenomenon whereby the effects of climate change, most notably rising sea levels and more frequent flooding and storm surges, alter housing values in a way that leads to gentrification. Objective To examine the climate gentrification following hurricane Katrina by (1) estimating the associations between flooding severity, ground elevation, and gentrification and (2) whether these relationships are modified by neighborhood level pre- and post-storm sociodemographic factors. Methods Lidar data collected in 2002 were used to determine elevation. Water gauge height of Lake Ponchartrain was used to estimate flood depth. Using census tracts as a proxy for neighborhoods, demographic, housing, and economic data from the 2000 decennial census and the 2010 and 2015 American Community Survey 5-year estimates US Census records were used to determine census tracts considered eligible for gentrification (median income < 2000 Orleans Parish median income). A gentrification index was created using tract changes in education level, population above the poverty limit, and median household income. Proportional odds ordinal logistic regression was used with product terms to test for effect measure modification by sociodemographic factors. Results Census tracts eligible for gentrification in 2000 were 80.2% black. Median census tract flood depth was significantly lower in areas eligible to undergo gentrification (0.70 m vs. 1.03 m). Residents of gentrification-eligible tracts in 2000 were significantly more likely to be black, less educated, lower income, unemployed, and rent their home rather than own. In 2015 in these same eligible tracts, areas that underwent gentrification became significantly whiter, more educated, higher income, less unemployed, and more likely to live in a multi-unit dwelling. Gentrification was inversely associated with flood depth and directly associated with ground elevation in eligible tracts. Marginal effect modification was detected by the effect of pre-storm black race on the relationships of flood depth and elevation with gentrification. Conclusions Gentrification was strongly associated with higher ground elevation in New Orleans. These results provide evidence to support the idea of climate gentrification described in other low-elevation major metropolitan areas like Miami, FL. High elevation, low-income, demographically transitional areas in particular – that is areas that more closely resemble high-income area demographics, may be vulnerable to future climate gentrification.

Louisiana↗
USGS2013

Quantifying wetland–aquifer interactions in a humid subtropical climate region: An integrated approach

Wetlands are widely recognized as sentinels of global climate change. Long-term monitoring data combined with process-based modeling has the potential to shed light on key processes and how they change over time. This paper reports the development and application of a simple water balance model based on long-term climate, soil, vegetation and hydrological dynamics to quantify groundwater–surface water (GW–SW) interactions at the Norman landfill research site in Oklahoma, USA. Our integrated approach involved model evaluation by means of the following independent measurements: (a) groundwater inflow calculation using stable isotopes of oxygen and hydrogen ( 16 O, 18 O, 1 H, 2 H); (b) seepage flux measurements in the wetland hyporheic sediment; and (c) pan evaporation measurements on land and in the wetland. The integrated approach was useful for identifying the dominant hydrological processes at the site, including recharge and subsurface flows. Simulated recharge compared well with estimates obtained using isotope methods from previous studies and allowed us to identify specific annual signatures of this important process during the period of study (1997–2007). Similarly, observations of groundwater inflow and outflow rates to and from the wetland using seepage meters and isotope methods were found to be in good agreement with simulation results. Results indicate that subsurface flow components in the system are seasonal and readily respond to rainfall events. The wetland water balance is dominated by local groundwater inputs and regional groundwater flow contributes little to the overall water balance.

Oklahoma↗