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USGS2009

Continental-scale patterns in soil geochemistry and mineralogy: results from two transects across the United States and Canada

In 2004, the US Geological Survey (USGS) and the Geological Survey of Canada (GSC) initiated a pilot study that involved collection of more than 1500 soil samples from 221 sites along two continental transects across Canada and the United States. The pilot study was designed to test and refine protocols for a soil geochemical survey of North America. The two transects crossed a wide array of soil parent materials, soil ages, climatic conditions, landforms, land covers and land uses. Sample sites were selected randomly at approximately 40-km intervals from a population defined as all soils of the continent. At each site, soils representing 0 to 5 cm depth, and the O, A, and C horizons, if present, were collected and analyzed for their near-total content of over 40 major and trace elements. Soils from 0–5 cm depth were also collected for analysis of organic compounds. Results from the transects confirm that soil samples collected at a 40-km spacing reveal coherent, continental- to subcontinental-scale geochemical and mineralogical patterns that can be correlated to aspects of underlying soil parent material, soil age and climate influence. The geochemical data also demonstrate that at the continental-scale the dominance of any of these major factors that control soil geochemistry can change across the landscape. Along both transects, soil mineralogy and geochemistry change abruptly with changes in soil parent materials. However, the chemical influence of a soil’s parent material can be obscured by changing climatic conditions. For the transects, increasing precipitation from west to east and increasing temperature from north to south affect both soil mineralogy and geochemistry because of climate effects on soil weathering and leaching, and plant productivity. Regional anomalous metal concentrations can be linked to natural variations in soil parent materials, such as high Ni and Cr in soils developed on ultramafic rocks in California or high P in soils formed on weathered Ordovician limestones in central Kentucky. On local scales, anomalous metal concentrations recognized in soil profiles, such as high P in soils from animal confinement sites, are consistent with local anthropogenic disturbances. At a larger scale, the distribution of Hg across the west to east transect demonstrates that it can be difficult to distinguish between natural or anthropogenic contributions and that many factors can contribute to an element’s spatial distribution. Only three samples in a subset of seventy-three 0–5 cm depth soil samples from the north to south transect had organochlorine pesticides values above the method detection limit, apparently related to historic usage of the pesticides DDT and dieldrin.

Applied Geochemistry↗

USGS2020

Stress gradients interact with disturbance to reveal alternative states in salt marsh: Multivariate resilience at the landscape scale

Stress gradients influence many ecosystem processes and properties, including ecosystem recovery from and resistance to disturbance. While recent analytical approaches have advanced multivariate metrics of ecosystem resilience that allow quantification of conceptual resilience models and identification of thresholds of state change, these approaches are not often translated to landscape scales. Using natural and restored salt marshes in Louisiana, USA, we quantified plant community recovery and resistance metrics along flooding stress gradients. n ‐dimensional hypervolumes of plant community biomass and structure were simulated using field data collected from disturbance‐recovery experiments. The relationships between multivariate resilience metrics and flooding stress gradients were then mapped at community‐ and landscape‐relevant scales by scaling with airborne‐derived data across the region. Greater pre‐disturbance abiotic stress decreased live belowground, but not aboveground, biomass, and ultimately led to lower post‐disturbance total recovery, recovery rates, and resistance of plant communities. Vegetated plots flooded >52% of the time transitioned to an alternative, unvegetated state after disturbance. Mapping revealed differences in spatial patterns of resilience‐ highlighting low, interior marsh edges as especially vulnerable to the combination of chronic flooding stress and acute disturbance. At the landscape scale, approximately half of the area (48%) is vulnerable to state change after pulse disturbances. Synthesis . Ultimately, we quantify the ball‐and‐cup conceptual model for a salt marsh ecosystem and its alternative state, mudflat. We find that increasing abiotic stress due to climate change diminishes ecosystem resilience, but the interaction with common episodic disturbances is necessary to reveal transitions to alternative states and quantify state change thresholds. Quantifying and mapping resilience and where alternative states may exist in this fashion improves ecologists’ ability to investigate the mechanisms of stress gradient control on emergent ecosystem properties, while providing spatially explicit resources for managing ecosystems according to their projected resilience.

Louisiana↗

USGS2011

Monitoring plan for vegetation responses to elk management in Rocky Mountain National Park

Rocky Mountain National Park (RMNP) in north-central Colorado supports numerous species of wildlife, including several large ungulate species among which Rocky Mountain elk (Cervus elaphus) are the most abundant. Elk are native to RMNP but were extirpated from the area by the late 1800s. They were reintroduced to the area in 1913-1914, and the elk herd grew to the point that it was actively managed from 1944 until 1968. In 1969, the active control of elk was discontinued and since then the herd has increased to a high point ranging from 2,800 to 3,500 between 1997 and 2001. In recent years, there has been growing concern over the condition of vegetation in the park and conflicts between elk and humans, both inside and outside the park. In response to these concerns, RMNP implemented an Elk and Vegetation Management Plan (EVMP) in 2009 to guide management actions in the park over a 20-year time period with the goal of reducing the impacts of elk on vegetation and restoring the natural range of variability in the elk population and affected plant and animal communities. The EVMP outlines the desired future condition for three vegetation communities where the majority of elk herbivory impacts are being observed: aspen, montane riparian willow, and upland herbaceous communities. The EVMP incorporates the principle of adaptive management whereby the effectiveness of management actions is assessed and adjusted as needed to successfully achieve objectives. Determination of whether vegetation objectives are being achieved requires monitoring and evaluation of target vegetation communities. The current report describes the design and implementation of a vegetation-monitoring program to help RMNP managers assess the effectiveness of their management actions and determine when and where to alter actions to achieve the EVMP's vegetation objectives. This monitoring plan details the process of selecting variables to be monitored, overall sampling design and structure, site selection, data collection methods, and statistical analyses to be used to conduct this monitoring program in conjunction with the EVMP. We report the baseline conditions observed at the time of the establishment of monitoring sites. We include detailed field protocols for site establishment and data collection, as well as timetables for sampling, so that RMNP staff will be able to continue monitoring the sites established during this implementation stage, and continue to add new sites when necessary, as the execution of the EVMP proceeds over the next 20 years.

Colorado↗

USGS2013

Bedrock and surficial geologic map of the Satan Butte and Greasewood 7.5’ quadrangles, Navajo and Apache Counties, northern Arizona

The geologic map of the Satan Butte and Greasewood 7.5’ quadrangles is the result of a cooperative effort of the U.S. Geological Survey (USGS) and the Navajo Nation to provide regional geologic information for management and planning officials. This map provides geologic information useful for range management, plant and animal studies, flood control, water resource investigations, and natural hazards associated with sand-dune mobility. The map provides connectivity to the regional geologic framework of the Grand Canyon area of northern Arizona. The map area encompasses approximately 314 km 2 (123 mi 2 ) within Navajo and Apache Counties of northern Arizona and is bounded by lat 35°37'30" to 35°30' N., long 109°45' to 110° W. The quadrangles lie within the southern Colorado Plateau geologic province and within the northeastern portion of the Hopi Buttes (Tsézhin Bií). Large ephemeral drainages, Pueblo Colorado Wash and Steamboat Wash, originate north of the map area on the Defiance Plateau and Balakai Mesa respectively. Elevations range from 1,930 m (6,330 ft) at the top of Satan Butte to about 1,787 m (5,860 ft) at Pueblo Colorado Wash where it exits the southwest corner of the Greasewood quadrangle. The only settlement within the map area is Greasewood, Arizona, on the north side of Pueblo Colorado Wash. Navajo Highway 15 crosses both quadrangles and joins State Highway 264 northwest of Ganado. Unimproved dirt roads provide access to remote parts of the Navajo Reservation.

Arizona↗

USGS2015

Water use in Georgia by county for 2010 and water-use trends, 1985–2010

Water use and water withdrawals and returns in 2010 are estimated for each major river basin, principal aquifer, water-planning region, and county in Georgia using data obtained from various Federal and State agencies and local sources. Offstream water use in 2010 is estimated for the categories of public supply, domestic, commercial, industrial, mining, irrigation, livestock, aquaculture, and thermoelectric power. Water-use trends for 1985 to 2010 are also shown. The period between 2007 and 2010 was a challenging time economically and climatologically in Georgia. During that period, the United States was in the midst of a major recession, resulting in decreases in the manufacturing and construction industries and large increases in unemployment. During 2007, 2008, and the latter half of 2010, precipitation in Georgia was substantially below the 30-year norm. According to the 2010 Census of Population and Housing, nearly 9.7 million people lived in Georgia. The water for about 85 percent of that population was provided by public water suppliers. Estimated total water withdrawals from ground-water and surface-water sources were about 4,670 million gallons per day (Mgal/d) in 2010, about a 15-percent reduction from 2005 (5,471 Mgal/d). In 2010, thermoelectric-power facilities (2,046 Mgal/d) and public-supply uses (1,121 Mgal/d) accounted for 68 percent of all water withdrawn in Georgia. Surface-water withdrawals were greatest for thermoelectric-power generation (2,043 Mgal/d), whereas irrigation used the largest amount of groundwater (599 Mgal/d). Surface water provided 78 percent of the 1,121 Mgal/day withdrawn for public supply in 2010. Typically, counties in northern Georgia withdraw a larger percentage of water from surface water than groundwater sources; whereas, counties in the southern part of the State withdraw more water from groundwater sources. Historically, water withdrawals in Georgia were highest in 1980 (6,725 Mgal/d). By 1990, water use had decreased by 20 percent to 5,353 Mgal/d, but increased to 6,487 Mgal/d in 2000. By 2005, water use had decreased to an estimated 5,471 Mgal/d, and declined further to 4,670 Mgal/d in 2010—a 30-percent decrease since 1980. This decline was evident across all water-use categories, but was greatest for surface-water withdrawals by thermoelectric-power facilities. The estimated total water use per capita in 1985 (total withdrawals for all categories divided by total population) was about 850 gallons per day (gal/d), steadily decreasing to about 798 gal/d in 2000, and decreasing further to 460 gal/d in 2010. Although water use declined among all use categories during that 10-year period, most of the decline in per capita water use was caused by the large decrease in water used for thermoelectric-power generation. Throughout 1985–2010 water withdrawn for thermoelectric-power generation has constituted the largest volume of offstream water use in Georgia. Total withdrawals for thermoelectric-power generation declined about 37 percent between 2000 and 2010, mostly due to the decommissioning of power plants in the State. Also during this period, several power plants were shut down and re-tooled to use natural gas-powered generators; thus, water withdrawals for cooling were substantially reduced. The decline in water withdrawals and use between 2005 and 2010 can probably be attributed to several factors working together during this period: (1) water conservation laws and policies along with advances in water-conservation technology; (2) the onset of a major recession in 2007; and (3) below average rainfall in 2007, 2008, and the latter half of 2010. Because of these factors, water withdrawn by public suppliers decreased by 4.8 percent (despite a nearly 11-percent increase in population served) and per capita use decreased by 19 percent between 2005 and 2010. About 2,225 Mgal/d of water was returned to Georgia streams and lakes in 2010 under the National Pollutant Discharge Elimination System program administered by the Georgia Environmental Protection Division. This amount is about 48 percent of the total water withdrawn from all sources in 2010. Water returns declined 39 percent between 1995 and 2010, mirroring the decline in water withdrawals during that period. In addition, land applications of treated wastewater increased steadily between 1995 and 2010.

Georgia↗

USGS1996

Influences of environmental settings on aquatic ecosystems in the Apalachicola-Chattahoochee-Flint River basin

The watershed boundary of the Apalachicola-Chattahoochee-Flint (ACF) River basin defines an aquatic ecosystem whose water quality is the result of complex interactions of natural and human influences on land and water resources. Topics relating to the basin's environmental setting-its physical, biological, and cultural characteristics-are summarized to provide an understanding of factors that influence water quality and the health of aquatic ecosystems. The ACF River basin lies partly in southwestern Georgia, southeastern Alabama, and northwestern Florida and covers 19,800 square miles in the Blue Ridge, the Piedmont, and the Coastal Plain Provinces. The basin includes the drainages of the Chattahoochee River and the Flint River, which meet to form the Apalachicola River. The Apalachicola River flows into the Gulf of Mexico at Apalachicola Bay. Basin hydrology and water quality are influenced by 16 mainstem reservoirs, 13 of which are on the Chattahoochee River. Ground water in the basin is contained in six aquifers-the surficial aquifer system, the Floridan aquifer system, the Claiborne aquifer, the Clayton aquifer, the Providence aquifer, and the crystalline-rock aquifer. Physiography, climate, and hydrology of the ACF River basin provide natural conditions that support a rich and abundant diversity of plants and animals. Although most of the ACF River basin has been altered by human activities, the basin's environment is noteworthy for its remaining biological diversity and the role it plays in sustaining biological productivity in Apalachicola Bay. The Bay produces 90 percent of Florida's and 13 percent of the Nation's oyster harvest; and functions as a nursery for penaeid shrimp, blue crabs, and a variety of fin fish. The diversity of the basin's aquatic fauna is noteworthy because the basin is home to (1) the largest number of fish species among Gulf Coast drainages east of the Mississippi River, (2) the largest assemblage of freshwater fish in Florida, (3) the largest number of mollusc species among western Florida drainages, and (4) the highest species density of amphibians and reptiles on the continent north of Mexico. Population of the ACF River basin in 1990 was estimated at 2.6 million. Nearly 90 percent of the total population lived in Georgia, and nearly 60 percent lived in the Metropolitan Atlanta area. The 1990 basin population is projected to increase by 15 percent to 3.0 million by the year 2000, and by 30 percent to 3.4 million by 2010. The largest increases in populations are projected for the Metropolitan Atlanta area. In 1972-76, approximately 59 percent of the basin was covered by forest, 29 percent was agricultural, 5 percent was wetland, 4 percent was urban, and 3 percent was water or barren land. Most of the original land cover of the basin has been transformed by human activity. Timber is the basin's largest cash crop and most forests consist of second-growth stands or large acreages of planted pine. The dominant agricultural land use in the Piedmont Province is pasture and confined feeding for dairy, livestock, and poultry production. Row-crop agriculture, orchards, and silviculture are most common in the Coastal Plain Province. The top five crops in order from most to least acres harvested in 1990 were peanuts, corn, soybeans, wheat, and cotton. The water in the basin is used for public and industrial supply, irrigation, power generation, navigation, and recreation. Although most public-supply withdrawals in the Blue Ridge and Piedmont Provinces are from surface-water sources, with the exception of counties near or immediately below the Fall Line, all publicly supplied water in the Coastal Plain is withdrawn from ground-water sources. Ground water supplied 18 percent of the basin's population served by public supply. Total water withdrawn in the ACF River basin in 1990 was 2,098 million gallons per day (Mgal/d), of which Georgia withdrew 82 percent and Florida and Alabama each withdrew 9 percent. Power generation is the single largest water use. Sixteen of the basin's 22 power generating plants are located along the mainstem of the Chattahoochee River. The U.S. Army Corps of Engineers maintains a navigation channel from the mouth of the Apalachicola River to Columbus, Ga., on the Chattahoochee River and to Bainbridge, Ga., on the Flint River. Water quality in the basin is influenced by the operation of 137 municipal wastewater-treatment facilities. In 1990, 354 Mgal/d of municipal wastewater was discharged within the ACF River basin. Eighty-eight percent of the wastewater was discharged into the Chattahoochee River basin, 10.6 percent into the Flint River basin, and 1.4 percent into the Apalachicola River basin. Two-thirds of the 938 stream miles in the Georgia portion of the ACF River basin having water quality that does not meet or only partially meets the designated-use criteria in the Chattahoochee River basin. The Chattahoochee River is the most heavily-used water resource both in the ACF River basin and in Georgia. Urban runoff or unknown nonpoint sources are cited as the causes of water-quality regulations in 72 percent of violations. The remaining causes primarily are combined sewer overflows in the Atlanta area, and discharges from municipal or industrial treatment facilities with inadequate treatment capabilities or operational deficiencies.

Alabama, Florida, Georgia↗

USGS1997

Stream-temperature characteristics in Georgia

Stream-temperature measurements for 198 periodic and 22 daily record stations were analyzed using a harmonic curve-fitting procedure. Statistics of data from 78 selected stations were used to compute a statewide stream-temperature harmonic equation, derived using latitude, drainage area, and altitude for natural streams having drainage areas greater than about 40 square miles. Based on the 1955-84 reference period, the equation may be used to compute long-term natural harmonic stream-temperature coefficients to within an on average of about 0.4? C. Basin-by-basin summaries of observed long-term stream-temperature characteristics are included for selected stations and river reaches, particularly along Georgia's mainstem streams. Changes in the stream- temperature regimen caused by the effects of development, principally impoundments and thermal power plants, are shown by comparing harmonic curves and coefficients from the estimated natural values to the observed modified-condition values.

Georgia↗

USGS2013

Statewide summary for Florida

Throughout the past century, emergent wetlands have been declining across the Gulf of Mexico. Emergent wetland ecosystems provide a multitude of resources, including plant and wildlife habitat, commercial and recreational economic activity, and natural barriers against storms. As emergent wetland losses increase, so does the need for information on the causes and effects of this loss; emergent wetland mapping, monitoring, and restoration efforts; and education. This report provides scientists, managers, and citizens with valuable baseline information on the status and trends of emergent wetlands along the coast of the Gulf of Mexico. The Statewide Summary for Florida provides status and trends information for Florida using what data is available during the 1950-2010 time period. The State of Florida (Figure 1) is approximately 151,670 km2 (58,560 mi2 ) large with an average elevation of 30.5 m (100 ft) (Dahl, 2005). The Florida gulf coast stretches approximately 1,000 km (621 miles) from the Alabama State line to the Dry Tortugas in the Florida Keys (Handley et al., 2007). The climate varies along the coast, ranging from temperate continental in the panhandle to oceanic subtropical in the Keys. Due to this climatic gradient, the Gulf coast of Florida is divisible into two ecoregions, the Louisianian in the north along the panhandle, and the West Indian in the south along the length of the peninsula (Bailey 1978). The Lousianian ecoregion extends from Cedar Key north and west along the panhandle to the Alabama state line. It is characterized by extensive emergent coastal wetlands, temperate fauna, small tidal ranges (

Florida↗

USGS2013

Florida Panhandle

Florida↗

USGS2013

Statewide summary for Louisiana: Chapter E in Emergent wetlands status and trends in the northern Gulf of Mexico: 1950-2010

Throughout the past century, emergent wetlands have been declining across the Gulf of Mexico. Emergent wetland ecosystems provide a variety of resources, including plant and wildlife habitat, commercial and recreational economic activity, and natural barriers against storms. As emergent wetland losses increase, so does the need for information on the causes and effects of this loss, emergent wetland mapping, monitoring and restoration efforts, and education. The U.S. Geological Survey and the U.S. Environmental Protection Agency’s Gulf of Mexico Program are committed to restoring, enhancing, and protecting these important ecosystems. The purpose of this report is to provide scientists, managers, and citizens with valuable baseline information on the status and trends of emergent wetlands along the coast of the Gulf of Mexico. This study examines the emergent wetlands of eight individual estuarine areas within the northern Gulf of Mexico region, as well as presenting statewide summaries for Texas, Louisiana, Mississippi, Alabama, and Florida. Each estuarine area is detailed in vignettes that address current status and historical trends of estuarine and palustrine emergent wetlands, emergent wetlands mapping and monitoring, causes of status change, restoration and enhancement activities, background information for the study area, and the methodology employed to analyze and document the historical trends and current status of emergent wetlands. This chapter examines the estuaries of Louisiana.

Louisiana↗

USGS2001

Type characters of non-native plant species in Great Lakes national parks (USA)

Non-native plant species are increasing in frequency and abundance in many natural areas in the United States. In Midwestern National Parks, as much as one third of the flora may be non-native. It was hypothesized that botanical characters of these species could be used to typify them and improve the methods of predicting invasions. Data on 19 characters of 341 non-native species from the four Great Lakes national lakeshores (Apostle Islands, Indiana Dunes, Pictured Rocks, and Sleeping Bear Dunes) and invasive non-native species for the State of Wisconsin were collected and studied. For many of the species, little data could be found, but for 139 of them, data were collected for at least 80% of the characters. The frequencies of classes of the characters were tabulated and ranked to typify the most common non-native species. This led to a description of a 'type species' just for these four National Parks. Three species of Cirsium, including Canada (C. arvense), marsh (C. palustre) and bull thistle (C. vulgare), matched the type species better than other species. C. vulgare occurs in more National Parks than the other thistles.

Indiana, Michigan, Wisconsin↗

USGS1995

Hawaii's endemic birds

The endemic landbirds of Hawaii, particularly the Hawaiian honeycreepers, an endemic subfamily of the cardueline finches, are one of the world's most dramatic examples of adaptive radiation and speciation (see glossary) in island ecosystems (Freed et al. 1987; Scott et al. 1988). From what is believed to have been a single successful colonization of the Hawaiian Archipelago by an ancestral species from North America, the honeycreepers evolved into a diverse array of species and subspecies of birds with bills ranging from thick, seed-eating beaks of the palila ( Loxioides bailleui ), to small insectivorous bills as seen on the `amakihi ( Hemignathus virens ), woodpecker-like adaptations of the `akiapola`au ( H. munroi ), and large, decurved nectar-feeding bills of the `i`iwi ( Vestiaria coccinea ). In addition to the honeycreepers, the historically documented endemic Hawaiian avifauna included three seabirds, several waterfowl, two raptors, and perching birds that include a species of crow, and representatives of Old World flycatchers, honeyeaters, and thrushes. In all, at least 71 endemic species and subspecies of Hawaiian birds existed at the time of Captain Cook's arrival in the Hawaiian Islands in 1778. Now, however, 76% of the Hawaiian birds are either extinct or endangered, and several of the remaining unlisted species are showing significant population declines. The arrival of humans to the Hawaiian Islands--starting with the Polynesians more than 1,500 years ago and continuing following European contact--drastically changed many natural ecosystems, leading not only to the extinction of many plant and animal species, but also to a significant reduction in both range and abundance for many other taxa. Originally, the Hawaiian birds were found in all habitat zones on each island, but today few native forest birds are found below 610-m (2,000-ft) elevation, and many of the wetland areas that once provided abundant habitat for waterbirds have been destroyed. Of the historically documented 71 taxa of endemic Hawaiian birds, 23 are now extinct, and 30 of the remaining 48 species and subspecies are listed as endangered or threatened by the U.S. Fish and Wildlife Service (USFWS 1992), many with few or only single populations remaining (Fig. 1; Table 1; Table 2). Studies of recently discovered fossil bird bones have further identified nearly 40 additional species of Hawaiian birds never seen alive by the post-Cook naturalists; many of these became extinct after the Polynesians arrived (Olson and James 1982; H. James, Smithsonian Institution, personal communication).

Hawai'i↗

USGS2013

Molecular techniques to distinguish morphologically similar Hydrilla verticillata , Egeria densa , Elodea nuttallii , and Elodea canadensis

The four submerged aquatic species, hydrilla (Hydrilla verticillata [monoecious and dioecious]), Brazilian waterweed (Egeria densa), Canadian waterweed (Elodea canadensis), and western waterweed (Elodea nuttallii), are difficult to positively identify because of their morphological similarity to each other, resulting in possible misidentification. This limits our ability to understand their past and present distribution, which is important in aquatic plant management. We investigated a molecular technique to identify these species, which are problematic because of their invasive nature on multiple continents. Approximately 100 samples of these species, ranging in age from 40-yr-old herbarium samples to recently collected plants, were collected from regions across the United States. The distribution and range of the samples collected in this research were compared to those reported in the literature. We confirmed information on the current wide distribution of both hydrilla biotypes in the United States and discovered that hydrilla had actually invaded the waterways near Washington, DC 6 yr earlier than originally reported. In addition, we found evidence of the confusion, dating back to the 1980s, between Canadian waterweed and western waterweed in the mid-Atlantic region of the United States. Canadian waterweed was previously reported as common and western waterweed as rare; however, our samples indicate the opposite is true. This information indicates there is a need for investigators to anticipate the spread of hydrilla populations to northern U.S. waterways, where it will compete with existing plant species, including Canadian and western waterweeds. Our ability to confirm distribution and pace of spread of invasive and noninvasive species will improve with increased application of molecular techniques.

Journal of Aquatic Plant Management↗

USGS2004

Fort Collins Science Center: Species and Habitats of Federal Interest

Ecosystem changes directly affect a wide variety of plant and animal species, floral and faunal communities, and groups of species such as amphibians and grassland birds. Appropriate management of public lands plays a crucial role in the conservation and recovery of endangered species and can be a key element in preventing a species from being listed under the Endangered Species Act. The Species and Habitats of Federal Interest Branch of the Fort Collins Science Center (FORT) conducts research on the ecology, habitat requirements, distribution and abundance, population dynamics, and genetics and systematics of many species facing threatened or endangered status or of special concern to resource management agencies. FORT scientists develop reintroduction and restoration techniques, technologies for monitoring populations, and novel methods to analyze data on population trends and habitat requirements. FORT expertise encompasses both traditional and specialized natural resource disciplines within wildlife biology, including population dynamics, animal behavior, plant and community ecology, inventory and monitoring, statistics and computer applications, conservation genetics, stable isotope analysis, and curatorial expertise.

Fact Sheet↗

USGS2006

Genetic structure of natural and restored shoalgrass Halodule wrightii populations in the NW Gulf of Mexico

The decline of seagrass communities worldwide has sparked an urgent need for effective restoration strategies, which require a working knowledge of population genetic structure. Halodule wrighti is a common seagrass of the Caribbean region that is being restored to areas of the Gulf of Mexico, yet little is known of its population genetics. This study provides an assessment of individual, clonal and population effects on the genetic structure of 4 natural H. wrightii populations occupying 170 km of coastline in and around Galveston Bay, Texas, for comparison with 7 restored populations ranging in age from 2 to 7 yr. By using molecular markers, in the form of amplified fragment length polymorphisms (AFLPs), we found considerable variation in clonal richness at the population scale (from 0.54 to 0.82), with the restored populations occupying an intermediate to high position within this range. Replicate sampling within individual seagrass beds of 3 to 5m diameter generally revealed higher levels of clonal richness, elevated by 4 to 22% over that at the population scale, suggesting that seed recruitment is more important at the local scale than at distances of >10 m. Genetic diversity was 2 to 3 times less than that expected for a widespread, outcrossing species like H. wrightii, although a 170% increase in the frequency of variable markers relative to the mean for all other populations was noted for a volunteer population that had recruited from a mixture of donor materials planted at a nearby restoration site. Within the spatial extent of this study, natural populations adhered to a model of isolation-by-distance, whereas donor materials from these same natural populations were undergoing a rapid genetic convergence within a restored site where they had been planted together.

Texas↗

USGS2000

Using new video mapping technology in landscape ecology

Biological and ecological monitoring continues to play an important role in the conservation of species, natural communities, and landscapes ( Spellerberg 1991 ). Although resource-monitoring programs have advanced knowledge about natural ecosystems, weaknesses persist in our ability to rapidly transfer landscape-scale information to the public. Ecologists continue to search for new technologies to address this problem and to communicate natural resource information quickly and effectively. New video mapping technology may provide much-needed help. Ecologists realize that only a small portion of large nature reserves can be monitored because of cost and logistical constraints. However, plant and animal populations are usually patchily distributed in subpopulations scattered throughout heterogeneous landscapes, and they are often associated with rare habitats. These subpopulations and rare habitats may respond differently to climate change, land use, and management practices such as grazing, fire suppression, prescribed burning, or invasion of exotic species ( Stohlgren et al. 1997b ). In many national parks, monuments, and wildlife reserves, a few long-term monitoring plots are used to infer the status and trends of natural resources in much larger areas. To make defensible inferences about populations, habitats, and landscapes, it is necessary to extrapolate from a few monitoring plots (local scale) to the larger, unsampled landscape with known levels of accuracy and precision. Recent technological developments have given population biologists and landscape ecologists a unique tool for bridging the data gap between small, intensively sampled monitoring plots and the greater landscape and for transferring this information quickly to resource managers and the public. In this article, we briefly describe this tool, a hand-held video mapping system linked to a geographic information system (GIS). We provide examples of its use in quantifying patterns of native and exotic plant species and cryptobiotic crusts in the new Grand Staircase–Escalante National Monument, Utah, and in surveying aspen clones and regeneration in Rocky Mountain National Park, Colorado.

BioScience↗

USGS2014

Natural regeneration processes in big sagebrush ( Artemisia tridentata )

Big sagebrush, Artemisia tridentata Nuttall (Asteraceae), is the dominant plant species of large portions of semiarid western North America. However, much of historical big sagebrush vegetation has been removed or modified. Thus, regeneration is recognized as an important component for land management. Limited knowledge about key regeneration processes, however, represents an obstacle to identifying successful management practices and to gaining greater insight into the consequences of increasing disturbance frequency and global change. Therefore, our objective is to synthesize knowledge about natural big sagebrush regeneration. We identified and characterized the controls of big sagebrush seed production, germination, and establishment. The largest knowledge gaps and associated research needs include quiescence and dormancy of embryos and seedlings; variation in seed production and germination percentages; wet-thermal time model of germination; responses to frost events (including freezing/thawing of soils), CO 2 concentration, and nutrients in combination with water availability; suitability of microsite vs. site conditions; competitive ability as well as seedling growth responses; and differences among subspecies and ecoregions. Potential impacts of climate change on big sagebrush regeneration could include that temperature increases may not have a large direct influence on regeneration due to the broad temperature optimum for regeneration, whereas indirect effects could include selection for populations with less stringent seed dormancy. Drier conditions will have direct negative effects on germination and seedling survival and could also lead to lighter seeds, which lowers germination success further. The short seed dispersal distance of big sagebrush may limit its tracking of suitable climate; whereas, the low competitive ability of big sagebrush seedlings may limit successful competition with species that track climate. An improved understanding of the ecology of big sagebrush regeneration should benefit resource management activities and increase the ability of land managers to anticipate global change impacts.

Rangeland Ecology and Management↗

USGS2009

Seed dispersal and seedling emergence in a created and a natural salt marsh on the Gulf of Mexico coast in Southwest Louisiana, U.S.A

Early regeneration dynamics related to seed dispersal and seedling emergence can contribute to differences in species composition among a created and a natural salt marsh. The objectives of this study were to determine (1) whether aquatic and aerial seed dispersal differed in low and high elevations within a created marsh and a natural marsh and (2) whether seedling emergence was influenced by marsh, the presence of openings in the vegetation, and seed availability along the northern Gulf of Mexico coast. Aerial seed traps captured a greater quantity of seeds than aquatic traps. Several factors influenced aquatic and aerial seed dispersal in a created and a natural salt marsh, including distance from the marsh edge, cover of existing vegetation, and water depth. The natural marsh had a high seed density of Spartina alterniflora and Distichlis spicata, the low-elevation created marsh had a high seed density of S. alterniflora, and the high-elevation created marsh had a high seed density of Aster subulatus and Iva frutescens. The presence of adult plants and water depth above the marsh surface influenced seed density. In the natural marsh, openings in vegetation increased seedling emergence for all species, whereas in the low-elevation created marsh, S. alterniflora had higher seedling density under a canopy of vegetation. According to the early regeneration dynamics, the future vegetation in areas of the low-elevation created marsh may become similar to that in the natural marsh. In the high-elevation created marsh, vegetation may be upland fringe habitat dominated by high-elevation marsh shrubs and annual herbaceous species. ?? 2009 Society for Ecological Restoration International.

Restoration Ecology↗