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At least 37 records · Page 2Linked to original sources
USGS2020

Methylmercury exposure in wildlife: A review of the ecological and physiological processes affecting contaminant concentrations and their interpretation

Exposure to methylmercury (MeHg) can result in detrimental health effects in wildlife. With advances in ecological indicators and analytical techniques for measurement of MeHg in a variety of tissues, numerous processes have been identified that can influence MeHg concentrations in wildlife. This review presents a synthesis of theoretical principals and applied information for measuring MeHg exposure and interpreting MeHg concentrations in wildlife. Mercury concentrations in wildlife are the net result of ecological processes influencing dietary exposure combined with physiological processes that regulate assimilation, transformation, and elimination. Therefore, consideration of both physiological and ecological processes should be integrated when formulating biomonitoring strategies. Ecological indicators, particularly stable isotopes of carbon, nitrogen, and sulfur, compound-specific stable isotopes, and fatty acids, can be effective tools to evaluate dietary MeHg exposure. Animal species differ in their physiological capacity for MeHg elimination, and animal tissues can be inert or physiologically active, act as sites of storage, transformation, or excretion of MeHg, and vary in the timing of MeHg exposure they represent. Biological influences such as age, sex, maternal transfer, and growth or fasting are also relevant for interpretation of tissue MeHg concentrations. Wildlife tissues that represent current or near-term bioaccumulation and in which MeHg is the predominant mercury species (such as blood and eggs) are most effective for biomonitoring ecosystems and understanding landscape drivers of MeHg exposure. Further research is suggested to critically evaluate the use of keratinized external tissues to measure MeHg bioaccumulation, particularly for less-well studied wildlife such as reptiles and terrestrial mammals. Suggested methods are provided to effectively use wildlife for quantifying patterns and drivers of MeHg bioaccumulation over time and space, as well as for assessing the potential risk and toxicological effects of MeHg on wildlife.

Science of the Total Environment↗
USGS2012

Nest survival of piping plovers at a dynamic reservoir indicates an ecological trap for a threatened population

In the past 60 years, reservoirs have reshaped riverine ecosystems and transformed breeding habitats used by the threatened piping plover (Charadrius melodus; hereafter plover). Currently, 29% of the Northern Great Plains plover population nests at reservoirs that might function as ecological traps because reservoirs have more diverse habitat features and greater dynamics in water levels than habitats historically used by breeding plovers. We examined factors influencing daily survival rates (DSR) of 346 plover nests at Lake Sakakawea (SAK; reservoir) during 2006–2009 by evaluating multiple a priori models, and we used our best model to hindcast nest success of plovers during 1985–2009. Our observed and hindcast estimates of nest success were low compared to published estimates. Previous findings indicate that plovers prefer nest sites that are low relative to water level. We found that elevation of nests above the water level had a strong positive correlation with DSR because water levels of SAK typically increased throughout the nesting period. Habitat characteristics on the reservoir differ from those that shaped nest-site selection for plovers. Accordingly, extraordinary nest loss occurs there in many years, largely due to inundation of nests, and based on low fledging rates those losses were not compensated by potential changes in chick survival. Therefore, our example supports the concept of ecological traps in birds because it addresses quantitative assessments of habitat preference and productivity over 25 years (since species listing) and affects a large portion of the population.

North Dakota↗
USGS2018

Ecological resilience indicators for salt marsh ecosystems

Salt marshes are coastal ecosystems within the intertidal zone, characterized by hypoxic, saline, soil conditions and low biodiversity. Low diversity arises from frequent disturbance and stressful conditions (i.e., high salinity and hypoxia), where vegetative reproduction and low competition result in mostly monotypic stands, with some differences in plant community influenced by flooding regime (described below). While there are several types of salt marshes in the Northern Gulf of Mexico (NGoM), ranging from low to high salt marshes and salt flats (Tiner, 2013), Spartina alterniflora–dominated salt marshes in the Coastal and Marine Ecological Classification Standard (CMECS) Low and Intermediate Salt Marsh Biotic Group (FGDC, 2012) are the most extensive and are the focus of this project. These salt marshes are classified as “Gulf Coast Cordgrass Salt Marsh” (CEGL004190; USNVC, 2016). Within the NGoM region, some salt marsh areas are dominated by other species such as Spartina patens and Juncus roemerianus, which both occupy higher elevations in high-precipitation zones (e.g., Louisiana, Alabama, Mississippi, and Florida). In lower precipitation regions (southern Texas), hypersaline conditions often develop yielding communities of succulent salt marsh plants (Batis and Salicornia spp.). In climatic zones with warmer winter temperatures, temperate salt marshes naturally transition to mangrove (generally in the southern Gulf of Mexico range) or, in areas with lower precipitation, to salt flats (generally in western part of the study area).

Gulf of Mexico↗
USGS2018

Ecological resilience indicators for mangrove ecosystems

Mangrove ecosystems are coastal wetland ecosystems dominated by mangrove species that are typically found in the intertidal zone, characterized by frequently flooded saline soil conditions. The majority of the approximately 500,000 acres of mangrove ecosystem in the United States occurs in the NGoM, and almost all of that is in Florida, with over 90 percent in the four southern counties of Lee, Collier, Miami-Dade, and Monroe. Scattered stands and individuals occur north and westward into Louisiana and Texas (Osland et al., 2016). The three common mangrove species are: black mangrove (Avicennia germinans), white mangrove (Laguncularia racemosa), and red mangrove (Rhizophora mangle). The mangrove system described in this project includes Tidal Mangrove Shrubland and Tidal Mangrove Forest as classified in CMECS (FGDC, 2012). It is classified as Caribbean Fringe Mangrove (G004) in the USNVC (2016), with a variety of distinct associations, based on species dominance and ecological setting.

Book chapter↗
USGS2019

Regional-scale associations between indicators of biological integrity and indicators of streamflow modification

Although streamflow is widely recognized as a controlling factor in stream health, empirical relations between indicators of anthropogenic modification of streamflow and ecological indicators have been elusive. The objective of this report is to build upon specific findings reported in recent publications by providing a library of empirical models that describe the relations between streamflow modification and indicators of biological integrity. Biological monitoring data from 812 streams and rivers across the United States were matched with sites where daily streamflow was also monitored by the U.S. Geological Survey. Of these sites, 118 were sampled by the U.S. Geological Survey along gradients of streamflow modification within 3 regional focus studies. The integrity of invertebrate and fish communities was expressed as a binary variable, “impaired” or “unimpaired,” signifying whether or not the composition and structure of the biological community was statistically reduced relative to regional reference sites. Streamflow modification at each gaged site was quantified with 509 streamflow statistics scaled to express the ratio of observed streamflow conditions to site-specific expected conditions in the absence of human influences on watershed hydrology. For each region, generalized additive modeling was used to examine relations between each indicator of streamflow modification and indicators of biological integrity (response variable). In every region examined, statistically defensible and ecologically realistic relations were found between indicators of streamflow modification and indicators of biological integrity. These findings can aid practitioners and managers seeking to (1) propose empirically based hypotheses about the specific components of streamflow regimes that are critical to aquatic communities, which can subsequently be explored in detail in a region or river basin of interest; and (2) predict biological responses to anthropogenic modification of specific components of the streamflow regime.

Open-File Report↗
USGS2013

Phenology-based, remote sensing of post-burn disturbance windows in rangelands

Wildland fire activity has increased in many parts of the world in recent decades. Ecological disturbance by fire can accelerate ecosystem degradation processes such as erosion due to combustion of vegetation that otherwise provides protective cover to the soil surface. This study employed a novel ecological indicator based on remote sensing of vegetation greenness dynamics (phenology) to estimate variability in the window of time between fire and the reemergence of green vegetation. The indicator was applied as a proxy for short-term, post-fire disturbance windows in rangelands; where a disturbance window is defined as the time required for an ecological or geomorphic process that is altered to return to pre-disturbance levels. We examined variability in the indicator determined for time series of MODIS and AVHRR NDVI remote sensing data for a database of ∼100 historical wildland fires, with associated post-fire reseeding treatments, that burned 1990–2003 in cold desert shrub steppe of the Great Basin and Columbia Plateau of the western USA. The indicator-based estimates of disturbance window length were examined relative to the day of the year that fires burned and seeding treatments to consider effects of contemporary variability in fire regime and management activities in this environment. A key finding was that contemporary changes of increased length of the annual fire season could have indirect effects on ecosystem degradation, as early season fires appeared to result in longer time that soils remained relatively bare of the protective cover of vegetation after fires. Also important was that reemergence of vegetation did not occur more quickly after fire in sites treated with post-fire seeding, which is a strategy commonly employed to accelerate post-fire vegetation recovery and stabilize soil. Future work with the indicator could examine other ecological factors that are dynamic in space and time following disturbance – such as nutrient cycling, carbon storage, microbial community composition, or soil hydrology – as a function of disturbance windows, possibly using simulation modeling and historical wildfire information.

California;Idaho;Nevada;Oregon;Utah;Washington↗
USGS2018

Remote sensing of tamarisk beetle (Diorhabda carinulata) impacts along 412 km of the Colorado River in the Grand Canyon, Arizona, USA

Tamarisk ( Tamarix spp.) is an invasive plant species that is rapidly expanding along arid and semi-arid rivers in the western United States. A biocontrol agent, tamarisk beetle ( Diorhabda carinulata ), was released in 2001 in California, Colorado, Utah, and Texas. In 2009, the tamarisk beetle was found further south than anticipated in the Colorado River ecosystem within the Grand Canyon National Park and Glen Canyon National Recreation Area. Our objectives were to classify tamarisk stands along 412 km of the Colorado River from the Glen Canyon Dam through the Grand Canyon National Park using 2009 aerial, high spatial resolution multispectral imagery, and then quantify tamarisk beetle impacts by comparing the pre-beetle images from 2009 with 2013 post-beetle images. We classified tamarisk presence in 2009 using the Mahalanobis Distance method with a total of 2500 training samples, and assessed the classification accuracy with an independent set of 7858 samples across 49 image quads. A total of 214 ha of tamarisk were detected in 2009 along the Colorado River, where each image quad, on average, included an 8.4 km segment of the river. Tamarisk detection accuracies varied across the 49 image quads, but the combined overall accuracy across the entire study region was 74%. Using the Normalized Difference Vegetation Index (NDVI) from 2009 and 2013 with a region-specific ratio of >1.5 decline between the two image dates (2009NDVI/2013NDVI), we detected tamarisk defoliation due to beetle herbivory. The total beetle-impacted tamarisk area was 32 ha across the study region, where tamarisk defoliation ranged 1–86% at the local levels. Our tamarisk classification can aid long-term efforts to monitor the spread and impact of the beetle along the river and the eventual mortality of tamarisk due to beetle impacts. Identifying areas of tamarisk defoliation is a useful ecological indicator for managers to plan restoration and tamarisk removal efforts.

Arizona↗
USGS2004

Estimating disturbance effects from military training using developmental instability and physiological measures of plant stress

We used developmental instability, water potential, and variable fluorescence to determine if populations of winged sumac (Rhus copallinum) were being negatively effected by military training disturbance. We established nine sites that represented a land-use disturbance gradient with three impact levels (low, medium, and high), the effects mostly due to mechanized infantry training maneuvers. Although mean values of developmental instability, water potential, and variable fluorescence differed significantly among sites, the patterns did not consistently differentiate sites relative to the disturbance gradient. At the population level, some measures of developmental instability and variable fluorescence were positively correlated. All nine sites consisted of habitat mosaics, with the abundance of higher quality habitat patches and canopy gaps closely related to habitat impacts. It may be that R. copallinum is selecting similar micro-environments at all sites and therefore minimizing inter-site variation in stress measures, despite large differences in overall habitat condition. Our results call for caution in developing ecological indicators using the response of physiological and morphological measures from a single plant species. ?? 2003 Elsevier Ltd. All rights reserved.

Ecological Indicators↗
USGS2018

Impacts of temporal revisit designs on the power to detect trend with a linear mixed model: An application to long-term monitoring of Sierra Nevada lakes

Long-term ecological monitoring programs often use linear mixed models to estimate trend in an ecological indicator sampled across large landscapes. A linear mixed model is versatile for estimating a linear trend in time as well as components of spatial and temporal variationin the case of unbalanced data structures , which are common in complex monitoring designs where limited sampling effort must be optimized over time and space. A power analysis was used to inform a lake chemistry monitoring design, including selecting the most appropriate temporal revisit design. Pilot data from surveys of lakes across large wilderness national parks (Sequoia, Kings Canyon, and Yosemite national parks) were used to obtain variance components for a Monte Carlo power simulation. Using a linear mixed model for a range of temporal revisit designs, sample sizes, and trend magnitudes, we evaluated the power to detect trend, the trend test size, and the relative bias of trend coefficient estimates for four continuous and normally distributed indicators. Contrary to prior research based on large-sample approximations that identified a single panel of sites visited annually as the revisit design generating the highest power, we found that the power to detect a 12-year trend based on the Wald t-test from a linear mixed model may be optimized by obtaining unbalanced data sets with limited to no annual replication. We emphasize the importance of examining variance composition, sample size, and the power and size of the trend test with Monte Carlo simulation when allocating sampling effort over time and space.

Ecological Indicators↗
USGS2011

Estimating aboveground forest biomass carbon and fire consumption in the U.S. Utah High Plateaus using data from the Forest Inventory and Analysis program, Landsat, and LANDFIRE

The concentrations of CO 2 and other greenhouse gases in the atmosphere have been increasing and greatly affecting global climate and socio-economic systems. Actively growing forests are generally considered to be a major carbon sink, but forest wildfires lead to large releases of biomass carbon into the atmosphere. Aboveground forest biomass carbon (AFBC), an important ecological indicator, and fire-induced carbon emissions at regional scales are highly relevant to forest sustainable management and climate change. It is challenging to accurately estimate the spatial distribution of AFBC across large areas because of the spatial heterogeneity of forest cover types and canopy structure. In this study, Forest Inventory and Analysis (FIA) data, Landsat, and Landscape Fire and Resource Management Planning Tools Project (LANDFIRE) data were integrated in a regression tree model for estimating AFBC at a 30-m resolution in the Utah High Plateaus. AFBC were calculated from 225 FIA field plots and used as the dependent variable in the model. Of these plots, 10% were held out for model evaluation with stratified random sampling, and the other 90% were used as training data to develop the regression tree model. Independent variable layers included Landsat imagery and the derived spectral indicators, digital elevation model (DEM) data and derivatives, biophysical gradient data, existing vegetation cover type and vegetation structure. The cross-validation correlation coefficient ( r value) was 0.81 for the training model. Independent validation using withheld plot data was similar with r value of 0.82. This validated regression tree model was applied to map AFBC in the Utah High Plateaus and then combined with burn severity information to estimate loss of AFBC in the Longston fire of Zion National Park in 2001. The final dataset represented 24 forest cover types for a 4 million ha forested area. We estimated a total of 353 Tg AFBC with an average of 87 MgC/ha in the Utah High Plateaus. We also estimated that 8054 Mg AFBC were released from 2.24 km 2 burned forest area in the Longston fire. These results demonstrate that an AFBC spatial map and estimated biomass carbon consumption can readily be generated using existing database. The methodology provides a consistent, practical, and inexpensive way for estimating AFBC at 30-m resolution over large areas throughout the United States.

Ecological Indicators↗
USGS2012

The effects of drought and disturbance on the growth and developmental instability of loblolly pine ( Pinus taeda L.)

Ecological indicators provide early warning of adverse environmental change, helping land managers adaptively manage their resources while minimizing costly remediation. In 1999 and 2000, we studied two such indicators, growth and developmental instability, of loblolly pine ( Pinus taeda L.) influenced by mechanized infantry training at Fort Benning, Georgia. Disturbed areas were used for military training; tracked and wheeled vehicles damaged vegetation and soils. Highly disturbed sites had fewer trees, diminished ground cover, warmer soils in the summer, and more compacted soils with a shallower A-horizon. We hypothesized that disturbance would decrease the growth of needles, branches, and tree rings, increase the complexity of tree rings, and increase the developmental instability of needles. Contrary to our expectations, however, disturbance enhanced growth in the first year of the study, possibly by reducing competition. In the second year, a drought reduced growth of branches and needles, eliminating the stimulatory effect of disturbance. Growth-ring widths increased with growing-season precipitation, and decreased with growing-season temperature over the last 40 years. Disturbance had no effect on tree-ring complexity, as measured by the Hurst exponent. Within-fascicle variation of current-year needle length, a measure of developmental instability, differed among the study populations, but appeared unrelated to mechanical disturbance or drought.

Ecological Indicators↗
USGS2022

Multi-species amphibian monitoring across a protected landscape: Critical reflections on 15 years of wetland monitoring in Grand Teton and Yellowstone national parks

Widespread amphibian declines were well documented at the end of the 20th century, raising concerns about the need to identify individual and interactive contributors to this global trend. At the same time, there was growing interest in the use of amphibians as ecological indicators. In the United States, wetland and amphibian monitoring programs were launched in some national parks as a necessary first step to evaluating the status and trends of amphibian populations within some of North America’s most protected areas. In Grand Teton and Yellowstone national parks, a multi-species amphibian monitoring program was launched by many of the authors in 2006 and continues to this day. This Viewpoint Article serves as a self-evaluation of our journey from conception through implementation of an ongoing, long-term monitoring program. This self-evaluation should provide a framework and guidance for other monitoring programs. We address whether we are fulfilling the program’s main objective of describing status and trends of the four amphibian species, discuss how a one-size-fits-all monitoring approach does not serve all species equally, and describe opportunities to bolster our core work using emerging statistical approaches and thoughtful integration of remote sensing and molecular tools. We also describe how the data generated over the program’s first 15 years have been useful beyond our initial goal of characterizing status and trend. Notably, our integration of climate datasets has allowed us to describe wetland and species-specific amphibian responses to variations in climate drivers. Documenting climate links to amphibian occurrence and their primary habitats has allowed us to identify which species, habitat types, and subregions within this large, protected landscape are most vulnerable to anticipated climate change. Recognizing that tools and threats change over time, it will be important to adapt our original monitoring design to maximize opportunities and use of resulting information. Maintaining engagement by multiple stakeholders and expanding our funding portfolio will also be necessary to sustain our program into the future. Finally, collaboration has become standard for long-term, cross-jurisdictional, landscape-scale monitoring. We argue that collaborative monitoring facilitates resource sharing, leveraging of limited funds, completion of work, and mutual learning. Such collaboration also increases the efficacy of conservation.

Wyoming↗
USGS2003

An index of ecological integrity for the Mississippi alluvial plain ecoregion: index development and relations to selected landscape variables

Macroinvertebrate community, fish community, water-quality, and habitat data collected from 36 sites in the Mississippi Alluvial Plain Ecoregion during 1996-98 by the U.S. Geological Survey were considered for a multimetric test of ecological integrity. Test metrics were correlated to site scores of a Detrended Correspondence Analysis of the fish community (the biological community that was the most statistically significant for indicating ecological conditions in the ecoregion) and six metrics--four fish metrics, one chemical metric (total ammonia plus organic nitrogen) and one physical metric (turbidity)--having the highest correlations were selected for the index. Index results indicate that sites in the northern half of the study unit (in Arkansas and Missouri) were less degraded than sites in the southern half of the study unit (in Louisiana and Mississippi). Of 148 landscape variables evaluated, the percentage of Holocene deposits and cotton insecticide rates had the highest correlations to index of ecological integrity results. sites having the highest (best) index scores had the lowest percentages of Holocene deposits and the lowest cotton insecticide use rates, indicating that factors relating to the amount of Holocene deposits and cotton insecticide use rates partially explain differences in ecological conditions throughout the Mississippi Alluvial Plain Ecoregion.

Arkansas, Kentucky, Louisiana, Mississippi, Missou↗
USGS2007

Ecological Status of Wyoming Streams, 2000-2003

The ecological status of perennial streams in Wyoming was determined and compared with the status of perennial streams throughout 12 States in the western United States, using data collected as part of the Western Pilot Environmental Monitoring and Assessment Program (EMAP-West). Results for Wyoming are compared and contrasted in the context of the entire EMAP-West study area (west-wide) and climatic regions (based on aggregated ecoregions) within Wyoming. In Wyoming, ecological status, estimated as the proportion of the perennial stream length in least disturbed, most disturbed, and intermediate disturbance condition, based on ecological indicators of vertebrate and invertebrate assemblages was similar, in many cases, to the status of those assemblages determined for EMAP-West. Ecological status based on chemical and physical habitat stressors also was similar in Wyoming to west-wide proportions in many cases. Riparian disturbance was one of the most common physical stressors west-wide and in Wyoming. The estimates of riparian disturbance indicated about 90 percent of the stream length in the xeric climatic region in Wyoming was rated most disturbed, compared to about 30 percent rated most disturbed in the mountain climatic region in Wyoming. Results from analyses using a macroinvertebrate multi-metric index (MMI) and macroinvertebrate ratio of observed to expected taxa (O/E) developed specifically for the west-wide EMAP study were compared to results using a macroinvertebrate MMI and O/E developed for Wyoming. Proportions of perennial stream length in various condition categories determined from macroinvertebrate MMIs often were similar in Wyoming to proportions observed west-wide. Differences were larger, but not extreme, between west-wide and Wyoming O/E models. An aquatic life use support decision matrix developed for interpreting the Wyoming MMI and O/E model data indicated about one-half of the stream length statewide achieves the State's narrative aquatic life use criteria, and the remainder of the stream length either exceeds the criteria, indicating partial or non-support of aquatic life Wyominguses, or is undetermined. These results provide initial estimates of aquatic life use support at a statewide basis as required for 305(b) reporting, and coupled with current and future State-level probability survey designs, a foundation for tracking conditions over time at multiple scales.

Scientific Investigations Report↗
USGS2004

Comparison of methods for determining streamflow requirements for aquatic habitat protection at selected sites on the Assabet and Charles Rivers, Eastern Massachusetts, 2000-02

Four methods used to determine streamflow requirements for habitat protection at nine critical riffle reaches in the Assabet River and Charles River Basins were compared. The methods include three standard setting techniques?R2Cross, Wetted Perimeter, and Tennant?and a diagnostic method, the Range of Variability Approach. One study reach is on the main stem of the Assabet River, four reaches are on tributaries to the Assabet River (Cold Harbor Brook, Danforth Brook, Fort Meadow Brook, and Elizabeth Brook), three are on the main stem of the Charles River, and one is on a tributary to the Charles River (Mine Brook). The strength of the R2Cross and Wetted-Perimeter methods is that they may be applied at ungaged locations whereas the Tennant method and the Range of Variability Approach require a period of streamflow record for analysis. Fish community assessments conducted at or near riffle sites in flowing reaches of the Assabet River and Charles River Basins were used to indicate ecological conditions. The fish communities in the main stem and tributary reaches of both the Assabet and Charles River Basins indicated degraded aquatic ecosystems. However, the degree of degradation differs between the two basins. The extreme predominance of tolerant, generalist species in the Charles River fish community demon-strates the cumulative impacts of flow, habitat, and water-chemistry degradation, combined with the effects of nearby impoundments and changing land use. The range of discharges for nine ungaged riffle reaches defined by the median R2Cross 3-of-3 criteria, R2Cross 2-of-3 criteria, and Wetted-Perimeter streamflow requirements, was 0.86 cubic foot per second per square mile, 0.18 cubic foot per second per square mile, and 0.23 cubic foot per second per square mile, respectively. Application of R2Cross and Wetted-Perimeter methods to sites with altered streamflows or at sites that are riffles only at low to moderate flows can result in a greater variability of streamflow requirements than would result if the methods were applied to riffles on natural channels with unaltered streamflows. The R2Cross 2-of-3 criteria and the Wetted-Perimeter streamflow requirements for the Assabet and Charles River sites show narrower interquartile ranges and lower median streamflow requirements than for 10 index streamflow-gaging stations in southern New England. This is especially evident for the R2Cross 2-of-3 criteria and Wetted-Perimeter results that were close to half of the flow requirements determined at the 10 southern New England stations. The R2Cross and Wetted-Perimeter methods were also compared to the Range of Variability Approach analysis and the Tennant Method. The median R2Cross 3-of-3 criteria streamflow requirement for the nine riffles is close to the 75th percentile of the monthly mean flows during the summer low-flow period from six streamflow-gaging stations near the Assabet and Charles River Basins having mostly unaltered flow. This streamflow requirement is close to the median Tennant 40-percent-flow requirement for good habitat condi-tion for the same six nearby stations. The R2Cross 2-of-3 criteria and Wetted-Perimeter results were less than the 25th-percentile of monthly mean flows during the summer months for the six stations. These streamflow requirements are in the poor habitat range as indicated by a Tennant analysis of the same six stations. These comparisons indicate that the R2Cross and Wetted-Perimeter methods underestimate streamflow requirements when applied to sites in smaller drainage areas and channels that are runs at higher flows.

Scientific Investigations Report↗
USGS2001

Duck populations as indicators of landscape condition in the Prairie Pothole Region

The Prairie Pothole Region of the northern Great Plains is an important region for waterfowl production because of the abundance of shallow wetlands. The ecological significance of the region and impacts from intensive agriculture prompted the U.S. Environmental Protection Agency to select it as one of the first areas for developing and evaluating ecological indicators of wetland condition. We examined hypothesized relations between indicators of landscape and wetland conditions and waterfowl abundance on 45 40 km2 study sites in North Dakota for 1995-96. Landscape condition was defined a priori as the ratio of cropland area to total upland area surrounding wetlands. Measures of waterfowl abundance included estimated numbers of breeding pairs (by species and total numbers) and , a species-specific correction factor which effectively adjusts breeding pair estimates for annual or area-related differences in pond size. Landscape indicators and waterfowl measures varied among regions. Results indicated that most areas in the Coteau region are of much higher quality for ducks than those in the Drift Plain, and areas in the Red River Valley are of the poorest quality for ducks. Regression models demonstrated the impact of agricultural development on breeding duck populations in the Prairie Pothole Region. The most consistent landscape indicators of waterfowl abundance were percent of cropland and grassland. Models were inconsistent among years and species. The potential biotic indicators of landscape and wetland condition examined here would be appropriate for temporal trend analyses, but because of inherent geographic variability would not be appropriate for single-year geographic trend analyses without more extensive evaluations to improve explanatory models

Environmental Monitoring and Assessment↗
USGS2007

Selected field parameters from streams and preliminary analytical data from water and macroinvertebrate samples, Central Colorado Assessment Project, task, 2004 and 2005

The U.S. Geological Survey (USGS) Central Colorado Assessment Project (CCAP) began in October 2003 and is planned to last through September 2008. One major goal of this project is to compare the relationships between surface-water chemistry and aquatic fauna in mined and unmined areas. To accomplish this goal, we are conducting a State-scale reconnaissance sampling program, in which we are collecting water and macroinvertebrate samples. Selected results from the first two years of project analyses are reported here. We plan to develop statistical models and use geographic information system (GIS) technology to quantify the relationships between ecological indicators of metal contamination in Rocky Mountain streams and water quality, landscape and land-use characteristics (for example, mine density, geology, geomorphology, vegetation, topography). Our research will test the hypothesis that physicochemical variables and ecological responses to metal concentrations in stream water in Rocky Mountain streams are ultimately determined largely by historical land uses.

Colorado↗
USGS2015

Site-scale disturbance and habitat development best predict an index of amphibian biotic integrity in Ohio shrub and forested wetlands

We determined the best predictors of an index of amphibian biotic integrity calculated from 54 shrub and forested wetlands in Ohio, USA using a two-step sequential holdout validation procedure. We considered 13 variables as predictors: four metrics of wetland condition from the Ohio Rapid Assessment Method (ORAM), a wetland vegetation index of biotic integrity, and eight metrics from a landscape disturbance index. For all iterations, the best model included the single ORAM metric that assesses habitat alteration, substrate disturbance, and habitat development within a wetland. Our results align with results of similar studies that have associated high scores for wetland vegetation indices of biotic integrity with low habitat alteration and substrate disturbance within wetlands. Thus, implementing similar management practices (e.g., not removing downed woody debris, retaining natural morphological features, decreasing nutrient input from surrounding agricultural lands) could concurrently increase ecological integrity of both plant and amphibian communities in a wetland. Further, our results have the unexpected effect of making progress toward a more unifying theory of ecological indices.

Ohio↗