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At least 1,657 records · Page 92Linked to original sources
USGS2011

Three experimental high-flow releases from Glen Canyon Dam, Arizona— Effects on the downstream Colorado River ecosystem

Three high-flow experiments (HFEs) were conducted by the U.S. Department of the Interior at Glen Canyon Dam, Arizona, in March 1996, November 2004, and March 2008. Also known as artificial or controlled floods, these scheduled releases of water above the dam's powerplant capacity were designed to mimic pre-dam seasonal flooding on the Colorado River. The goal of the HFEs was to determine whether high flows could be used to benefit important downstream resources in Glen Canyon National Recreation Area and Grand Canyon National Park that have been affected by the existence and operation of Glen Canyon Dam. These downstream resources include native fish, particularly endangered humpback chub (Gila cypha), terrestrial and aquatic sandbar habitats, cultural sites, and recreational resources. This Fact Sheet summarizes HFE-related studies published since 1996 and outlines a possible strategy for implementing future HFEs.

Arizona↗
USGS2011

Delivering climate science for the nation's fish, wildlife, and ecosystems: The U.S. Geological Survey National Climate Change and Wildlife Science Center

Changes to the Earth's climate-temperature, precipitation, and other important aspects of climate-pose significant challenges to our Nation's natural resources now and will continue to do so. Managers of land, water, and living resources need to understand the impacts of climate change-which will exacerbate ongoing stresses such as habitat fragmentation and invasive species-so they can design effective response strategies. In 2008 Congress created the National Climate Change and Wildlife Science Center (NCCWSC) within the U.S. Geological Survey (USGS); this center was formed to address challenges resulting from climate change and to empower natural resource managers with rigorous scientific information and effective tools for decision-making. Located at the USGS National Headquarters in Reston, Virginia, the NCCWSC has invested over $20M in cutting-edge climate change research and is now leading the effort to establish eight regional Department of the Interior (DOI) Climate Science Centers (CSCs).

Fact Sheet↗
USGS2011

Wind energy and wildlife research at the Forest and Rangeland Ecosystem Science Center

The United States has embarked on a goal to increase electricity generation from clean, renewable sources by 2012. Towards this end, wind energy is emerging as a widely distributed form of renewable energy throughout the country. The national goal is for energy from wind to supply 20 percent of the country's electricity by 2030. As with many land uses, trade-offs exist between costs and benefits. New wind developments are occurring rapidly in parts of the United States, often leaving little time for evaluation of potential site-specific effects. These developments are known to affect wildlife, directly from fatality due to collision with the infrastructure and indirectly from loss of habitat and migration routes. The Department of the Interior, in particular, is challenged to balance energy development on public lands and also to conserve fish and wildlife. The Secretary of the Interior has proposed a number of initiatives to encourage responsible development of renewable energy. These initiatives are especially important in the western United States where large amounts of land are being developed or evaluated for wind farms.

Fact Sheet↗
USGS2014

Delivering climate science about the Nation's fish, wildlife, and ecosystems: the U.S. Geological Survey National Climate Change and Wildlife Science Center

Changes to the Earth’s climate—temperature, precipitation, and other climate variables—pose significant challenges to our Nation’s natural resources. Managers of land, water, and living resources require an understanding of the impacts of climate change—which exacerbate ongoing stresses such as habitat alteration and invasive species—in order to design effective response strategies. In 2008, Congress created the National Climate Change and Wildlife Science Center (NCCWSC) within the U.S. Geological Survey (USGS). The center was formed to address environmental challenges resulting from climate and land-use change and to provide natural resource managers with rigorous scientific information and effective tools for decision making. Located at the USGS National Headquarters in Reston, Virginia, the NCCWSC has established eight regional Department of the Interior (DOI) Climate Science Centers (CSCs) and has invested over $93 million (through fiscal year 2013) in cutting-edge climate change research.

Fact Sheet↗
USGS2015

Changing Arctic Ecosystems: Updated forecast: Reducing carbon dioxide (CO2) emissions required to improve polar bear outlook

The Arctic is warming faster than other regions of the world due to the loss of snow and ice, which increases the amount of solar energy absorbed by the region. The most visible consequence has been the rapid decline in sea ice over the last 3 decades-a decline projected to bring long ice-free summers if greenhouse gas (GHG) emissions are not significantly reduced. The polar bear ( Ursus maritimus ) depends on sea ice over the biologically productive continental shelves of the Arctic Ocean as a platform for hunting seals. In 2008, the U.S. Fish and Wildlife Service listed the polar bear as threatened under the Endangered Species Act (ESA) due to the threat posed by sea ice loss. The polar bear was the first species to be listed due to forecasted population declines from climate change.

Arctic↗
USGS2026

Fossil footprints and Ice Age ecosystems of White Sands National Park

Introduction In September 2021, National Park Service staff, U.S. Geological Survey scientists, and an international team of researchers revealed evidence in the form of human footprints at White Sands National Park, New Mexico, that showed people were present in North America between 23,000 and 21,000 years ago. This time was during the Last Glacial Maximum, when large ice sheets covered much of the continent. The results stunned the scientific community and sparked a global debate. The story of how the discoveries were made, how they upended traditional thought, and how they “rewrote the book” on the earliest phases of North American prehistory is a classic example of the process of science.

New Mexico↗
USGS2012

Stream ecosystems change with urban development

The healthy condition of the physical living space in a natural stream—defined by unaltered hydrology (streamflow), high diversity of habitat features, and natural water chemistry—supports diverse biological communities with aquatic species that are sensitive to disturbances. In a highly degraded urban stream, the poor condition of the physical living space—streambank and tree root damage from altered hydrology, low diversity of habitat, and inputs of chemical contaminants—contributes to biological communities with low diversity and high tolerance to disturbance.

General Information Product↗
USGS2025

Uranium mining, the Grand Canyon region, and the science of an ecosystem

Illustration of U.S. Geological Survey science at breccia pipe mines in the Grand Canyon region. The upper left portion shows a cross section of a breccia pipe and rock layers (far upper left) in a panoramic view of the Grand Canyon with upper right depicting rock pinnacles the Havasupai Tribe call Wi’i Gileeva. The right portion depicts a spring. The Colorado River bisects the illustration. A typical breccia pipe uranium mine site is shown in the lower left. Local plant and animal species studied are also included.

Arizona↗
USGS2002

Rocky Mountain snowpack chemistry network: History, methods, and the importance of monitoring mountain ecosystems

Because regional-scale atmospheric deposition data in the Rocky Mountains are sparse, a program was designed by the U.S. Geological Survey to more thoroughly determine the quality of precipitation and to identify sources of atmospherically deposited pollution in a network of high-elevation sites. Depth-integrated samples of seasonal snowpacks at 52 sampling sites, in a network from New Mexico to Montana, were collected and analyzed each year since 1993. The results of the first 5 years (1993–97) of the program are discussed in this report. Spatial patterns in regional data have emerged from the geographically distributed chemical concentrations of ammonium, nitrate, and sulfate that clearly indicate that concentrations of these acid precursors in less developed areas of the region are lower than concentrations in the heavily developed areas. Snowpacks in northern Colorado that lie adjacent to both the highly developed Denver metropolitan area to the east and coal-fired powerplants to the west had the highest overall concentrations of nitrate and sulfate in the network. Ammonium concentrations were highest in northwestern Wyoming and southern Montana.

Rocky Mountains↗
USGS2003

African dust carries microbes across the ocean: are they affecting human and ecosystem health?

Atmospheric transport of dust from northwest Africa to the western Atlantic Ocean region may be responsible for a number of environmental hazards, including the demise of Caribbean corals; red tides; amphibian diseases; increased occurrence of asthma in humans; and oxygen depletion (eutrophication) in estuaries. Studies of satellite images suggest that hundreds of millions of tons of dust are trans-ported annually at relatively low altitudes across the Atlantic Ocean to the Caribbean Sea and southeastern United States. The dust emanates from the expanding Sahara/Sahel desert region in Africa and carries a wide variety of bacteria and fungi. The U.S. Geological Survey, in collaboration with the NASA/Goddard Spaceflight Center, is conducting a study to identify microbes--bacteria, fungi, viruses--transported across the Atlantic in African soil dust. Each year, millions of tons of desert dust blow off the west African coast and ride the trade winds across the ocean, affecting the entire Caribbean basin, as well as the southeastern United States. Of the dust reaching the U.S., Florida receives about 50 percent, while the rest may range as far north as Maine or as far west as Colorado. The dust storms can be tracked by satellite and take about one week to cross the Atlantic.

Open-File Report↗
USGS2003

Ecosystem history of southern and central Biscayne Bay: Summary report on sediment core analyses

During the last century, the environs of Biscayne Bay have been greatly affected by anthropogenic alteration through urbanization of the Miami/Dade County area. The sources, timing, delivery, and quality of freshwater flow into the Bay have been changed by construction of a complex canal system that controls movement of water throughout south Florida. Changes in shoreline and sub-aquatic vegetation and marine organisms have been observed and changes in water delivery are believed to be the cause. Current restoration goals are attempting to restore natural flow of fresh water into Biscayne and Florida Bays and to restore the natural fauna and flora, but first we need to determine pre-alteration baseline conditions in order to establish targets and performance measures for restoration. This research is part of an ongoing study designed to address the needs of the Biscayne Bay Coastal Wetlands Project (BBCW) of the Comprehensive Everglades Restoration Plan (CERP). By establishing the natural patterns of temporal change in salinity, water quality, vegetation, and benthic fauna in Biscayne Bay and the nearby wetlands over the last 100- 500 years the USGS, in collaboration with our partners, will provide the data necessary to set realistic targets to achieve the BBCW Project goals. Six cores from three sites in Biscayne Bay were collected in April 2002 for multidisciplinary multi-proxy analyses. This report details the results of these analyses and compares the 2002 cores to cores collected in 1997. The following are our significant findings to date: The salinity of central Biscayne Bay has become increasingly marine and increasingly stable over the last 100 years. At No Name Bank, prior to approximately 1915, the inter-decadal and decadal salinity fluctuations appear to have been greater than after 1915 when salinities stabilized at that site. Continental shelf/open marine influence on the sites has increased during the 20th century. There is no indication of inter-decadal salinity extremes or periods of hypersalinity. Freshwater and mesohaline salinities have had a minor influence on No Name bank throughout the time of deposition. At Featherbed Bank, the influence is reduced to mesohaline salinities. Card Bank has experienced relatively large swings in salinity over multi-decadal and centennial timescales, compared to central Biscayne Bay, but marine influence at the site has increased over the last century. Indications of regional scale patterns have been found, especially in the shell chemistry data and the pollen assemblages. These regional patterns indicate that the changes are not site specific and may not be limited to Biscayne Bay. Sub-aquatic vegetation has undergone bay-wide patterns of change over the last 200-500 years, which includes expansion prior to 1900 and declines during the last century in central Biscayne Bay. Thalassia appears to have increased at all three core sites sometime between 1550 and 1750 AD. A decline in Thalassia appears to have occurred after 1950 at No Name Bank and slightly earlier in the 20th century at Featherbed Bank. Card Bank does not appear to have experienced any declines in vegetation on an inter-decadal scale during the 20th century. Molluscan faunal abundance and diversity have undergone significant changes in central Biscayne Bay. Indicators of increased organic-rich sediments at No Name occur between 1869 to 1888 and between the 1930’s to 1975. These changes may correlate to human activities (settlement, population growth). These findings represent a first step towards the project’s goal to reconstruct the history of Biscayne Bay and they provide us with a working model to be tested at other sites. It is clear from our findings that Biscayne Bay has been a dynamic environment over the last 500 years, with natural changes occurring in salinity and benthic habitats. However, several significant changes have occurred in the 20th century: 1) increased stabilization of marine salinities; 2) declines in seagrass in central Biscayne Bay; 3) dramatic changes in molluscan abundance and diversity in central Biscayne Bay. The question remains - how do we better differentiate natural cycles of change from anthropogenic change within these observed trends? The preliminary implications from our research are that changes in salinity and benthic habitats have occurred naturally in Biscayne Bay on inter-decadal to centennial scales, perhaps due to climatic changes, changes in sea level, bank migrations, or a combination of factors. However, further work needs to be done to determine which components of change in the 20th century are human-induced and which are natural. By examining the historical records preserved in the sediments of Biscayne Bay, we can provide restoration trust agencies with the information necessary to set realistic targets and performance measures for Biscayne Bay.

Florida↗