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At least 91 records · Page 5Linked to original sources
USGS2021

The application of metacommunity theory to the management of riverine ecosystems

River managers strive to use the best available science to sustain biodiversity and ecosystem function. To achieve this goal requires consideration of processes at different scales. Metacommunity theory describes how multiple species from different communities potentially interact with local-scale environmental drivers to influence population dynamics and community structure. However, this body of knowledge has only rarely been used to inform management practices for river ecosystems. In this article, we present a conceptual model outlining how the metacommunity processes of local niche sorting and dispersal can influence the outcomes of management interventions and provide a series of specific recommendations for applying these ideas as well as research needs. In all cases, we identify situations where traditional approaches to riverine management could be enhanced by incorporating an understanding of metacommunity dynamics. A common theme is developing guidelines for assessing the metacommunity context of a site or region, evaluating how that context may affect the desired outcome, and incorporating that understanding into the planning process and methods used. To maximize the effectiveness of management activities, scientists, and resource managers should update the toolbox of approaches to riverine management to reflect theoretical advances in metacommunity ecology.

WIREs Water↗
USGS2025

The Grouse & Grazing Project: Effects of cattle grazing on demographic traits of greater sage-grouse

Greater sage-grouse (Centrocercus urophasianus) were once widespread within sagebrush -grassland ecosystems of western North America, but populations have declined since the mid-1960s. Though sage-grouse were not listed as threatened or endangered under the Endangered Species Act (ESA), when examined in 2015, they remain a species of interest and concern. Roughly half of the sage-grouse’s remaining habitat is on federal land, most of it managed by the Bureau of Land Management (BLM) and the U.S. Forest Service (USFS). Livestock grazing is the most extensive land use within sage-grouse habitat and the effects of livestock grazing on sage-grouse are often debated. The extensive decade-long research project summarized in this report was initiated to provide rigorous experimental research to inform the debate regarding the relationship between livestock grazing and sage-grouse. In 2012, the Idaho Grouse & Grazing Project was started with several partners including the University of Idaho, BLM, Idaho Department of Fish and Game (IDFG), and other partners to evaluate the effects of cattle grazing on sage-grouse vital rates. Many additional supporters have provided resources to this research effort including the Public Lands Council, Idaho Cattle Association, Idaho Governor’s Office of Species Conservation, Western Association of Fish & Wildlife Agencies, U.S. Fish and Wildlife Service, USFS, and numerous grazing associations and ranchers in Idaho. This 10-year research project was a scientifically rigorous and replicated experiment, occurring across five study sites in Idaho. This document is intended to provide a summary of the findings of this unprecedented study. Annual reports are available on the project’s website: https://idahogrousegrazing.org and scientific papers are being prepared and submitted to journals. The project focused on the influence of spring cattle grazing on sage-grouse vital rates across five study sites in Idaho including 21 BLM grazing pastures. From 2014-2023, we captured 1,343 grouse, documented the fate of 1,285 nests, and tracked 399 broods. Vegetation was characterized at 4,777 plots and grazing utilization levels were recorded at >30,000 locations. Because insects are an important food source for sage-grouse hens and their chicks, insect biomass and diversity were also examined in this study. We collected arthropods in 12,151 pitfall samples and 6,217 sweep-net samples across 786 plots within our five study sites. At each study site, three or four grazing treatments were implemented after two years of pre-treatment field investigations. These controlled cattle grazing treatments included spring-grazing in even years, spring-grazing in odd years, spring-and-fall grazing in alternating years, and a no grazing (or rested) control. Once grazing treatments were implemented at a study site, we measured sage-grouse demographic traits for 4-8 years post-treatment. Stocking rate (grazing intensity) was assessed across pastures each year and was influenced by vegetation communities, topography, and water sources. Grazed pastures exhibited lower grass cover and height compared to the no grazing pastures, and the extent of this difference varied based on annual precipitation levels. Rested pastures maintained higher grass cover and grass height, but the differences in habitat structure did not consistently translate to differences in sage-grouse demographic traits. Apparent nesting success varied annually and by site, ranging from 24% to 44% over the study period. Like some other studies, results from this research show that successful (i.e., hatched) sage-grouse nests have taller grass heights than failed nests. The average grass height surrounding successful nests in grazed pastures was shorter than that surrounding successful nests in non-grazed (i.e., rested) pastures. It is well documented that grazing reduces grass height, and these observations have led to widely held assumptions that livestock grazing reduces grass height which negatively affects sage-grouse nesting habitat. At the pasture scale, this study has found that sage-grouse nesting success is no greater in pastures that were rested for 4-8 years than those currently or recently grazed. This study gives no indication that removing cattle from pastures affected nesting success. We found some evidence that nest density varied among the grazing treatments, but we did not see compelling evidence of increases in density of nesting hens following cessation of grazing in the no grazing treatments. Brood survival varied by site and year but showed no strong effect of grazing treatment. Climatic conditions, particularly drought in 2021, had a greater effect on brood survival than grazing metrics. We also found no differences in hen survival among the grazing treatments. Results of this study suggest that hens nesting in spring and fall grazed pastures had similar or even slightly higher brood survival than hens in the rested pastures or the spring grazed pastures. Arthropod biomass and species diversity varied among our study sites and the differences between grazed and rested pastures also varied among study sites. Average biomass and diversity of arthropods was higher in the spring grazed pastures on two of three sites examined but higher in the rested pastures on the other site examined. Some taxa of arthropods were more abundant in grazed pastures while other taxa were more abundant in rested pastures. For example, Carabidae (Ground Beetles) and Formicidae (Ants) had higher biomass in grazed pastures, while Tenebrionidae (Darkling Beetles) and Acrididae (Grasshoppers) had higher biomass in non-grazed pastures. Results indicate that grazing effects on arthropod biomass and arthropod diversity are study site-dependent, suggesting a need to better quantify the most important prey taxa for sage-grouse chicks and to better control for other factors that influence arthropod abundance. Based on results of this research, livestock grazing, when properly managed, does not appear to negatively impact sage-grouse nest survival or brood success. This study provides critical insights for land managers balancing livestock production with sage-grouse conservation, supporting adaptive grazing strategies that maintain both economic and ecological objectives.

Idaho↗
USGS2010

Cartographic Production for the FLaSH Map Study: Generation of Rugosity Grids, 2008

Project Summary This series of raster data is a U.S. Geological Survey (USGS) Data Series release from the Florida Shelf Habitat Project (FLaSH). This disc contains two raster images in Environmental Systems Research Institute, Inc. (ESRI) raster grid format, jpeg image format, and Geo-referenced Tagged Image File Format (GeoTIFF). Data is also provided in non-image ASCII format. Rugosity grids at two resolutions (250 m and 1000 m) were generated for West Florida shelf waters to 250 m using a custom algorithm that follows the methods of Valentine and others (2004). The Methods portion of this document describes the specific steps used to generate the raster images. Rugosity, also referred to as roughness, ruggedness, or the surface-area ratio (Riley and others, 1999; Wilson and others, 2007), is a visual and quantitative measurement of terrain complexity, a common variable in ecological habitat studies. The rugosity of an area can affect biota by influencing habitat, providing shelter from elements, determining the quantity and type of living space, influencing the type and quantity of flora, affecting predator-prey relationships by providing cover and concealment, and, as an expression of vertical relief, can influence local environmental conditions such as temperature and moisture. In the marine environment rugosity can furthermore influence current flow rate and direction, increase the residence time of water in an area through eddying and current deflection, influence local water conditions such as chemistry, turbidity, and temperature, and influence the rate and nature of sedimentary deposition. State-of-the-art computer-mapping techniques and data-processing tools were used to develop shelf-wide raster and vector data layers. Florida Shelf Habitat (FLaSH) Mapping Project (http://coastal.er.usgs.gov/flash) endeavors to locate available data, identify data gaps, synthesize existing information, and expand our understanding of geologic processes in our dynamic coastal and marine systems.

Data Series↗
USGS2017

The Moquah Barrens Research Natural Area: Loss of a pine barrens ecosystem

The Moquah Barrens Research Natural Area (RNA) was established by the Chequamegon National Forest and the Lakes States Forest Experiment Station in 1935 with a research objective well-suited to the needs of the Forest Service and the scientific understanding of ecosystem function prevalent at the time of establishment. The original research plan was never implemented, which led to a joint Forest-Station decision in 1956 to disestablish the RNA. However, that decision was never implemented. A series of management decisions made after 1956 led to the loss of the pine barrens ecosystem originally encompassed by the RNA. This loss is not irretrievable and the work necessary to recover the original ecosystem is possible under existing RNA management guidelines. The experience of the Moquah Barrens RNA can be used by the Forest Service to improve overall management of the entire system of research natural areas. Two main areas of opportunity are identified: 1) implement an improved approach to managing official records associated with RNAs; and 2) adopt a management framework suitable for long-term ecological projects.

Wisconsin↗
USGS2022

Great Lakes lake trout thiamine monitoring program annual report

The U.S. Geological Survey’s Great Lakes Science Center (GLSC), Eastern Ecological Science Center, and Columbia Environmental Research Center (CERC), and the State University of New York (SUNY) Brockport have conducted in collaboration with partner agencies a cooperative program to monitor thiamine concentrations in lake trout eggs since the late 1990s. In 2021, egg thiamine concentrations were highly variable at each sampling site. No eggs samples with thiamine concentrations less than the 4 nmol/g threshold recommended for successful lake trout reproduction were collected in Lakes Superior, Huron, Erie, and Champlain. In contrast, every site in Lakes Michigan and Ontario and Cayuga Lake had some lake trout eggs below 4 nmol/g. Time series of mean lake trout egg thiamine concentrations showed high temporal and spatial variability within the Great Lakes region.

Great Lakes↗
USGS2020

Assessing the risks posed by SARS-CoV-2 in and via North American bats — Decision framing and rapid risk assessment

The novel β-coronavirus, SARS-CoV-2, may pose a threat to North American bat populations if bats are exposed to the virus through interaction with humans, if the virus can subsequently infect bats and be transmitted among them, and if the virus causes morbidity or mortality in bats. Further, if SARS-CoV-2 became established in bat populations, it could possibly serve as a source for new infection in humans, domesticated animals, or other wild animals. Wildlife management agencies in the United States are concerned about these potential risks and have begun to issue guidance regarding work that brings humans into contact with bats, but decision making is difficult because of the high degree of uncertainty about many of the relevant processes that could lead to virus transmission and establishment. The risk assessment described in this report was undertaken to provide management agencies with an understanding of the likelihood that the various steps in the causal pathways would lead to SARS-CoV-2 infection of North American bats from people. This assessment focused on the active season for bats in the temperate zone of North America (April 15 through November 15), and used Myotis lucifugus (little brown bats) as a surrogate species. At the time of this work (April 2020), no empirical data about the effects of SARS-CoV-2 on North American bats were available, so a formal process of expert judgment was used to elicit estimates of the underlying parameters. Twelve experts in bat ecology, epidemiology, virology, and wildlife disease from the United States, United Kingdom, and Australia participated in the elicitation. A Monte Carlo simulation model was used to integrate the parameter estimates elicited from the experts and to predict the likelihood of exposure and infection in bats through a series of transmission pathways, with particular attention to capturing uncertainty in the predictions. Given the current state of knowledge as expressed by the expert panel, the results of this assessment indicate that there is a non-negligible risk of transmission of SARS-CoV-2 from humans to bats. For example, if a research scientist were shedding SARS-CoV-2 virus while handling bats under the field protocols used in North America prior to the COVID-19 pandemic, the risk model indicates that 50 percent (uncertainty, 15–84 percent) of those bats could be exposed to virus, and 17 percent (uncertainty, 3–51 percent) could become infected. Use of personal protective equipment, especially a respirator, is expected to reduce the exposure risk. The expert panel estimated that exposure risk from research scientists could be reduced 94–96 percent (uncertainty, 86–99 percent) through proper use of appropriate N95 respirators (a type of mechanical filter worn over the nose and mouth), dedicated clothing (such as Tyvek coveralls), and gloves. Should any North American bats become infected with SARS-CoV-2, the expert panel estimated that there is an approximately 33-percent chance the virus could spread within a bat population. This study, conducted by the U.S. Geological Survey in cooperation with the U.S. Fish and Wildlife Service, identified several critical uncertainties that could affect the estimate of risks associated with SARS-CoV-2 entering bat populations—notably, the underlying probability that a human would be shedding virus while working with bats, the likelihood of the virus replicating in bat tissue, and the likelihood of transmission of the virus within bat populations. Ongoing empirical work during May–October 2020 may shed light on these issues. Follow-up work is needed to better understand the probability of transmission of SARS-CoV-2 to bats from the general public; the manner in which the probabilities of exposure, infection, and transmission would differ during hibernation compared to the breeding season; and the likelihood of important effects, like morbidity and mortality in bats, the possibility of zoonosis from a North American bat reservoir, and effects of and on other wildlife.

North America↗
USGS2025

Great Lakes lake trout (Salvelinus namaycush) thiamine monitoring program annual report

Thiamine deficiency in lake trout ( Salvelinus namaycush ) eggs has been linked to early life-stage mortality in the Great Lakes from the 1960s through the 1990s, potentially affecting lake trout recruitment. In response, the U.S. Geological Survey’s Great Lakes Science Center (GLSC), Eastern Ecological Science Center (EESC), and Columbia Environmental Research Center (CERC), and the State University of New York (SUNY) Brockport, in collaboration with partner agencies, initiated a cooperative monitoring program in the late 1990s to assess thiamine concentrations in lake trout eggs. In 2024, egg thiamine concentrations continued to show high variability across sampling sites. No samples with thiamine concentrations below the 4 nmol/g threshold recommended for successful reproduction were observed in Lakes Superior or Huron. In contrast, between 11% and 88% of lake trout sampled from sites in Lakes Michigan, Ontario, Champlain, and the Finger Lakes had egg thiamine concentrations below this critical threshold. Time series data revealed substantial temporal and spatial variation in mean lake trout egg thiamine concentrations across the Great Lakes region.

Finger Lakes, Great Lakes, Lake Champlain↗
USGS2024

Great Lakes lake trout (Salvelinus namaycush) thiamine monitoring program annual report

Thiamine deficiency in lake trout eggs has been identified to induce early life-stage mortality in the Great Lakes in the 1960s through the 1990s and potentially affecting lake trout recruitment. As a results, the U.S. Geological Survey’s Great Lakes Science Center (GLSC), Eastern Ecological Science Center, and Columbia Environmental Research Center (CERC), and the State University of New York (SUNY) Brockport, in collaboration with partner agencies, have conducted a cooperative program to monitor thiamine concentrations in lake trout Salvelinus namaycush eggs since the late 1990s. In 2023, egg thiamine concentrations were highly variable at each sampling site. No egg samples with thiamine concentrations less than the 4 nmol/g threshold recommended for successful lake trout reproduction were collected in Lakes Superior or Huron. In contrast, 3 to 52% of the lake trout collected at sites in Lakes Michigan, Huron, Ontario and Champlain, and Cayuga Lake had eggs below 4 nmol/g. Time series of mean lake trout egg thiamine concentrations showed high temporal and spatial variability within the Great Lakes region.

Cayuga Lake, Lake Champlain, Lake Erie, Lake Huron↗
USGS2015

Atlas of relations between climatic parameters and distributions of important trees and shrubs in North America: Revisions for all taxa from the United States and Canada and new taxa from the western United States

This is the seventh volume in an atlas series that explores the relations between the geographic distributions of woody plant species and climatic variables in North America. A 25-kilometer (km) equal-area grid of modern climatic and bioclimatic variables was constructed from weather data. The geographic distributions of selected tree and shrub species were digitized, and the presence or absence of each species was determined for each point on the 25-km grid, thus providing a basis for comparing climatic data and species' distributions. The relations between climate and plant distributions are presented in graphical and tabular form. The results of this effort are intended primarily for use in biogeographic, ecologic, paleoclimatic, and global-change research. This volume of the atlas provides numerous changes, updates, and enhancements from previous volumes. Its geographic coverage is now restricted to Canada and the continental United States, and the source and time period of the climatic data have changed. New variables were added, including monthly values for temperature and precipitation, and measures of interannual variability. The distribution maps for all previously published species were redigitized, some distribution maps were revised, and 148 new species were added from the arid and semiarid western United States. The graphical displays were expanded to illustrate the new climatic variables, and the data tables were modified to provide more detail on the population distributions of plant taxa relative to climatic variables.

North America↗
USGS2015

Predicting ecological responses of the Florida Everglades to possible future climate scenarios: Introduction

Florida’s Everglades stretch from the headwaters of the Kissimmee River near Orlando to Florida Bay. Under natural conditions in this flat landscape, water flowed slowly downstream as broad, shallow sheet flow. The ecosystem is markedly different now, altered by nutrient pollution and construction of canals, levees, and water control structures designed for flood control and water supply. These alterations have resulted in a 50 % reduction of the ecosystem’s spatial extent and significant changes in ecological function in the remaining portion. One of the world’s largest restoration programs is underway to restore some of the historic hydrologic and ecological functions of the Everglades, via a multi-billion dollar Comprehensive Everglades Restoration Plan. This plan, finalized in 2000, did not explicitly consider climate change effects, yet today we realize that sea level rise and future changes in rainfall (RF), temperature, and evapotranspiration (ET) may have system-wide impacts. This series of papers describes results of a workshop where a regional hydrologic model was used to simulate the hydrology expected in 2060 with climate changes including increased temperature, ET, and sea level, and either an increase or decrease in RF. Ecologists with expertise in various areas of the ecosystem evaluated the hydrologic outputs, drew conclusions about potential ecosystem responses, and identified research needs where projections of response had high uncertainty. Resource managers participated in the workshop, and they present lessons learned regarding how the new information might be used to guide Everglades restoration in the context of climate change.

Florida↗
USGS2017

Designing a high-frequency nutrient and biogeochemical monitoring network for the Sacramento–San Joaquin Delta, northern California

Executive Summary This report is the third in a series of three reports that provide information about how high-frequency (HF) nutrient monitoring may be used to assess nutrient inputs and dynamics in the Sacramento–San Joaquin Delta, California (Delta). The purpose of this report is to provide the background, principles, and considerations for designing an HF nutrient-monitoring network for the Delta to address high-priority, nutrient-management questions. The report starts with discussion of the high-priority management questions to be addressed, continues through discussion of the questions and considerations that place demands and constraints on network design, discusses the principles applicable to network design, and concludes with the presentation of three example nutrient-monitoring network designs for the Delta. For three example network designs, we assess how they would address high-priority questions that have been identified by the Delta Regional Monitoring Program (Delta Regional Monitoring Program Technical Advisory Committee, 2015). This report, along with the other two reports of this series (Kraus and others, 2017; Downing and others, 2017), was drafted in cooperation with the Delta Regional Monitoring Program to help scientists, managers, and planners understand how HF data improve our understanding of nutrient sources and sinks, drivers, and effects in the Delta. The first report in the series (Kraus and others, 2017) provides an introduction to the reasons for and fundamental concepts behind using HF monitoring measurements, including a brief summary of nutrient status and trends in the Delta and an extensive literature review showing how and where other research and monitoring programs have used HF monitoring to improve our understanding of nutrient cycling. The report covers the various technologies available for HF nutrient monitoring and presents the different ways HF monitoring instrumentation may be used for both fixed station and spatial assessments. Finally, it presents numerous examples of how HF measurements are currently (2017) being used in the Delta to examine how nutrients and nutrient cycling are related to aquatic habitat conditions. The second report in the series (Downing and others, 2017) summarizes information about HF nutrient and associated biogeochemical monitoring in the north Delta. The report synthesizes data available from the nutrient and water quality monitoring network currently (2017) operated by the U.S. Geological Survey in this ecologically important region of the Delta. In the report, we present and discuss the available data at various timescales—first at the monthly, seasonal, and inter-annual timescales; and, second, for comparison, at the tidal and event timescales. As expected, we determined that there is substantial variability in nitrate concentrations at short timescales, such as within a few hours, but also significant variability at longer timescales such as months or years. This high variability affects calculation of fluxes and loads, indicating that HF monitoring is necessary for understanding and assessing flux-based processes and outcomes in Delta tidal environments.

California↗
USGS2000

Ecotoxicology of Amphibians and Reptiles

For many years, ecological research on amphibians and reptiles has lagged behind that of other vertebrates such as fishes, birds, and mammals, despite the known importance of these animals in their environments. The lack of study has been particularly acute in the he area of ecotoxicology where the number of published scientific papers is a fraction of that found for the other vertebrate classes. Recently, scientists have become aware of severe crises among amphibian populations, including unexplained and sudden extinctions, worldwide declines, and hideous malformations. In many of these instances, contaminants have been listed as probable contributors. Data on the effects of contaminants on reptiles are so depauperate that even the most elementary interpretations are difficult. This state-of-the-science review and synthesis of amphibian and reptile ecotoxicology demonstrates the inter-relationships among distribution, ecology, physiology, and contaminant exposure, and interprets these topics as they pertain to comparative toxicity, population declines, malformations, and risk assessment . In this way, the book identifies and serves as a basis for the most pressing research needs in the coming years. The editors have invited 27 other internationally respected experts to examine the state of existing data in specific areas, interpret it in light of current problems, and identify research gaps and needs. Through its emphasis on recent research, extensive reviews and synthesis, Ecotoxicology of Amphibians and Reptiles will remain a definitive reference work well into the new century.

SETAC Technical Publications Series.↗
USGS2016

Modeling the effects of tile drain placement on the hydrologic function of farmed prairie wetlands

The early 2000s saw large increases in agricultural tile drainage in the eastern Dakotas of North America. Agricultural practices that drain wetlands directly are sometimes limited by wetland protection programs. Little is known about the impacts of tile drainage beyond the delineated boundaries of wetlands in upland catchments that may be in agricultural production. A series of experiments were conducted using the well-published model WETLANDSCAPE that revealed the potential for wetlands to have significantly shortened surface water inundation periods and lower mean depths when tile is placed in certain locations beyond the wetland boundary. Under the soil conditions found in agricultural areas of South Dakota in North America, wetland hydroperiod was found to be more sensitive to the depth that drain tile is installed relative to the bottom of the wetland basin than to distance-based setbacks. Because tile drainage can change the hydrologic conditions of wetlands, even when deployed in upland catchments, tile drainage plans should be evaluated more closely for the potential impacts they might have on the ecological services that these wetlands currently provide. Future research should investigate further how drainage impacts are affected by climate variability and change.

Journal of the American Water Resources Associatio↗
USGS2017

Used-habitat calibration plots: A new procedure for validating species distribution, resource selection, and step-selection models

“Species distribution modeling” was recently ranked as one of the top five “research fronts” in ecology and the environmental sciences by ISI's Essential Science Indicators (Renner and Warton 2013), reflecting the importance of predicting how species distributions will respond to anthropogenic change. Unfortunately, species distribution models (SDMs) often perform poorly when applied to novel environments. Compounding on this problem is the shortage of methods for evaluating SDMs (hence, we may be getting our predictions wrong and not even know it). Traditional methods for validating SDMs quantify a model's ability to classify locations as used or unused. Instead, we propose to focus on how well SDMs can predict the characteristics of used locations. This subtle shift in viewpoint leads to a more natural and informative evaluation and validation of models across the entire spectrum of SDMs. Through a series of examples, we show how simple graphical methods can help with three fundamental challenges of habitat modeling: identifying missing covariates, non-linearity, and multicollinearity. Identifying habitat characteristics that are not well-predicted by the model can provide insights into variables affecting the distribution of species, suggest appropriate model modifications, and ultimately improve the reliability and generality of conservation and management recommendations.

Ecography↗
USGS2025

Three decades of World Recreational Fishing Conferences: What have we learned about the dynamics of recreational fisheries?

Recreational fishing extends beyond catching fish, connecting individuals with nature, generating environmental stewards and contributing significantly to both local, regional and national economies. Assessing potential impacts on ecosystems and social-ecological systems requires dedicated multi- and interdisciplinary research and integrative management and policy approaches. Managing recreational fisheries effectively also necessitates transdisciplinary thinking, yet this poses continued challenges, as researchers and managers balance specialized expertise with innovative, boundary-crossing perspectives in light of limited funding in a rapidly changing social-ecological environment. The World Recreational Fishing Conference (WRFC) serves as the leading global scientific forum for addressing these challenges, fostering interdisciplinary exchange among scientists, managers, policy makers and stakeholders. The papers in this special issue represent the output of the last WRFC in Melbourne, Australia in 2023. By reviewing the content of the papers published in the present special issue, we illustrate the critical role of collaborative spaces, such as the WRFC, in bridging different expertise and approaches and fostering innovation, thereby securing adaptive management and conservation of recreational fisheries in response to global changes. Evaluating the development of the WRFC over three decades highlights how this conference series represents a leading think tank serving the entire network of recreational fisheries professionals globally.

Fisheries Management and Ecology↗
USGS2000

Global GIS database. Digital atlas of Central and South America

This CD-ROM contains a digital atlas of the countries of Central and South America. This atlas is part of a global database compiled from USGS and other data sources at the nominal scale of 1:1 million and is intended to be used as a regional-scale reference and analytical tool by government officials, researchers, the private sector, and the general public. The atlas includes free GIS software or may also be used with ESRI's ArcView software. Customized ArcView tools, specifically designed to make the atlas easier to use, are also included. The atlas contains the following datasets: country political boundaries, digital shaded relief map, elevation, slope, hydrology, locations of cities and towns, airfields, roads, railroads, utility lines, population density, geology, ecological regions, historical seismicity, volcanoes, ore deposits, oil and gas fields, climate data, landcover, vegetation index, and lights at night.

Data Series↗
USGS2016

Preserving reptiles for research

What are voucher specimens and why do we collect them? Voucher specimens are animals and/or their parts that are deposited in a research museum to document the occurrence of a taxon at a specific location in space and time (Pleijel et al., 2008; Reynolds and McDiarmid, 2012). For field biologists, vouchers are the repeatable element of a field study as they allow other biologists, now and in the future, to confirm the identity of species that were studied. The scientific importance of a voucher specimen or series of specimens is that other people are afforded the opportunity to examine the entire animal and confirm or correct identifications. A photographic record is somewhat useful for recording the occurrence of a species, but such records can be insufficient for reliable confirmation of specific identity. Even if a photo shows diagnostic characters of currently recognized taxa, it may not show characters that separate taxa that may be described in the future. Substantial cryptic biodiversity is being found in even relatively well-known herpetofaunas (Crawford et al., 2010), and specimens allow researchers to retroactively evaluate the true diversity in a study as understanding of taxonomy evolves. They enable biologists to study the systematic relationships of populations by quantifying variation in different traits. Specimens are also a source of biological data such as behaviour, ecology, epidemiology, and reproduction through examination of their anatomy, reproductive and digestive tracts, and parasites (Suarez and Tsutsui, 2004). Preserving reptiles as vouchers is not difficult, although doing it properly requires care, effort, and time. Poorly preserved vouchers can invalidate the results and conclusions of your study because of the inability to confirm the identity of your study animals. Good science requires repeatability of observations, and the absence of vouchers or poorly preserved ones prevents such confirmation. Due to space restrictions, we are unable to go into as much detail as we would like in this chapter. A number of publications give more details on some topics discussed in this chapter, such as Pisani (1973), Pisani and Villa (1974), Etheridge (1996), Karns (1986), McDiarmid (1994), Cortez et al. (2006), Foster (2012) (and subchapters therein), Reynolds and McDiarmid (2012), and Simmons (2015). Although some of these works focus on amphibians, they also apply to reptiles in many aspects.

Book chapter↗
USGS2017

Automated cropland mapping of continental Africa using Google Earth Engine cloud computing

The automation of agricultural mapping using satellite-derived remotely sensed data remains a challenge in Africa because of the heterogeneous and fragmental landscape, complex crop cycles, and limited access to local knowledge. Currently, consistent, continent-wide routine cropland mapping of Africa does not exist, with most studies focused either on certain portions of the continent or at most a one-time effort at mapping the continent at coarse resolution remote sensing. In this research, we addressed these limitations by applying an automated cropland mapping algorithm (ACMA) that captures extensive knowledge on the croplands of Africa available through: (a) ground-based training samples, (b) very high (sub-meter to five-meter) resolution imagery (VHRI), and (c) local knowledge captured during field visits and/or sourced from country reports and literature. The study used 16-day time-series of Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) composited data at 250-m resolution for the entire African continent. Based on these data, the study first produced accurate reference cropland layers or RCLs (cropland extent/areas, irrigation versus rainfed, cropping intensities, crop dominance, and croplands versus cropland fallows) for the year 2014 that provided an overall accuracy of around 90% for crop extent in different agro-ecological zones (AEZs). The RCLs for the year 2014 (RCL2014) were then used in the development of the ACMA algorithm to create ACMA-derived cropland layers for 2014 (ACL2014). ACL2014 when compared pixel-by-pixel with the RCL2014 had an overall similarity greater than 95%. Based on the ACL2014, the African continent had 296 Mha of net cropland areas (260 Mha cultivated plus 36 Mha fallows) and 330 Mha of gross cropland areas. Of the 260 Mha of net cropland areas cultivated during 2014, 90.6% (236 Mha) was rainfed and just 9.4% (24 Mha) was irrigated. Africa has about 15% of the world’s population, but only about 6% of world’s irrigation. Net cropland area distribution was 95 Mha during season 1, 117 Mha during season 2, and 84 Mha continuous. About 58% of the rainfed and 39% of the irrigated were single crops (net cropland area without cropland fallows) cropped during either season 1 (January-May) or season 2 (June-September). The ACMA algorithm was deployed on Google Earth Engine (GEE) cloud computing platform and applied on MODIS time-series data from 2003 through 2014 to obtain ACMA-derived cropland layers for these years (ACL2003 to ACL2014). The results indicated that over these twelve years, on average: (a) croplands increased by 1 Mha/yr, and (b) cropland fallows decreased by 1 Mha/year. Cropland areas computed from ACL2014 for the 55 African countries were largely underestimated when compared with an independent source of census-based cropland data, with a root-mean-square error (RMSE) of 3.5 Mha. ACMA demonstrated the ability to hind-cast (past years), now-cast (present year), and forecast (future years) cropland products using MODIS 250-m time-series data rapidly, but currently, insufficient reference data exist to rigorously report trends from these results.

ISPRS Journal of Photogrammetry and Remote Sensing↗