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At least 1,423 records · Page 79Linked to original sources
USGS2006

Northern Florida reef tract benthic metabolism scaled by remote sensing

Holistic rates of excess organic carbon production (E) and calcification for a 0.5 km 2 segment of the backreef platform of the northern Florida reef tract (NFRT) were estimated by combining biotope mapping using remote sensing with community metabolic rates determined with a benthic incubation system. The use of ASTER multispectral satellite imaging for the spatial scaling of benthic metabolic processes resulted in errors in E and net calcification (G) of 48 and 431% respectively, relative to estimates obtained using AISA hyperspectral airborne scanning. At 19 and 125%, the E and G errors relative to the AISA-based estimates were less pronounced for an analysis that used IKONOS multispectral satellite imagery to spatially extrapolate the chamber process measurements. Our scaling analysis indicates that the holistic calcification rate of the backreef platform of the northern Florida reef tract is negligible at 0.07 g CaCO 3 m -2 d -1 . All of the mapped biotopes in this reef zone are net heterotrophic, resulting in an estimated holistic excess production rate of -0.56 g C m -2 d -1 , and an overall gross primary production to respiration ratio of 0.85. Based on our finding of ubiquitous heterotrophy, we infer that the backreef platform of the NFRT is a sink for external inputs of suspended particulate organic matter. Further, our results suggest that the inward advection of inorganic nutrients is not a dominant forcing mechanism for benthic biogeochemical function in the NFRT. We suggest that the degradation of the northern Florida reef tract may parallel the community phase shifts documented within other reef systems polluted by organic detritus.

Florida↗
USGS2005

An introduction to mid-Atlantic seasonal pools

Seasonal pools, also known as vernal ponds, provide important ecological services to the mid-Atlantic region. This publication serves as an introduction to seasonal pool ecology and management; it also provides tools for exploring seasonal pools, including a full-color field guide to wildlife. Seasonal pools are defined as having four distinctive features: surface water isolation, periodic drying, small size and shallow depth, and support of a characteristic biological community. Seasonal pools experience regular drying that excludes populations of predatory fish. Thus, pools in the mid-Atlantic region provide critical breeding habitat for amphibian and invertebrate species (e.g., spotted salamander (Ambystoma maculatum), wood frog (Rana sylvatica), and fairy shrimp (Order Anostraca)) that would be at increased risk of predation in more permanent waters. The distinctive features of seasonal pools also make them vulnerable to human disturbance. In the mid-Atlantic region, land-use changes pose the greatest challenges to seasonal pool conservation. Seasonal pools are threatened by direct loss (e.g., filling or draining of the pool) as well as by destruction and fragmentation of adjoining terrestrial habitat. Many of the species that depend on seasonal pools for breeding spend the majority of their lives in the surrounding lands that extend a radius of 1000 feet or more from the pools; these vital habitats are being transected by roads and converted to other land uses. Other threats to seasonal pools include biological introductions and removals, mosquito control practices, amphibian diseases, atmospheric deposition, and climate change. The authors recommend a three-pronged strategy for seasonal pool conservation and management in the mid-Atlantic region: education and research, inventory and monitoring of seasonal pools, and landscape-level planning and management.

Report↗
USGS1998

Low-flow water-quality characterization of the Gore Creek watershed, upper Colorado River basin, Colorado, August 1996

The Upper Colorado River Basin (UCOL) is one of 59 National Water-Quality Assessment (NAWQA) study units designed to assess the status and trends of the Nation?s water quality (Leahy and others, 1990). The UCOL study unit began operation in 1994, and surface-water-quality data collection at a network of 14 sites began in October 1995 (Apodaca and others, 1996; Spahr and others, 1996). Gore Creek, which flows through Vail, Colorado, originates in pristine alpine headwaters and is designated a gold-medal trout fishery. The creek drains an area of about 102 square miles and is a tributary to the Eagle River. Gore Creek at the mouth near Minturn (site 13 in fig. 1) is one of the 14 sites in the UCOL network. This site was selected to evaluate water quality resulting from urban development and recreational land use. The Gore Creek watershed has undergone rapid land-use changes since the 1960?s as the Vail area shifted from traditional mountain ranchlands to a four-season resort community. Residential, recreational, commercial, and transportation development continues near Gore Creek and its tributaries to support the increasing permanent and tourist population of the area. Interstate 70 runs through the watershed from Vail Pass near site 14, along the eastern side of Black Gore Creek, and along the northern side of the main stem of Gore Creek to the mouth of the watershed (fig. 1). A major local concern is how increasing urbanization/recreation affects the water quality, gold-medal trout fishery, and aesthetic values of Gore Creek. An evaluation of the spatial characteristics of water quality in the watershed upstream from site 13 at the mouth of Gore Creek (fig. 1) can provide local water and land managers with information necessary to establish water policy and make land-use planning decisions to maintain or improve water quality. Historical data collected at the mouth of Gore Creek provide information about water quality resulting from land use, but a synoptic sampling is needed to determine the distribution and sources of water-quality constituents at one point in time. In August 1996, a low-flow synoptic sampling for analyses of water-quality properties and constituents at sites in the Gore Creek watershed was done by the U.S. Geological Survey, in cooperation with the Town of Vail, Eagle River Water and Sanitation District, Upper Eagle River Water Authority, and Northwest Colorado Council of Governments, to evaluate the water quality of Gore Creek. The August low-flow period can be important from water-quality and stream ecology perspectives. There is less water available to dilute any contaminants entering the streams, and stream temperatures are highest during August. Physical habitat for aquatic plants and animals is smaller than during most other times of the year. To address these more extreme water-quality and ecological conditions, the synoptic sampling was conducted during the summer low-flow period. Specific objectives of this sampling included: 1. Establish a current data set representing the spatial characteristics of low-flow water-quality conditions in the Gore Creek watershed, and 2. Develop some understanding of land-use and water-quality relations in the watershed. This fact sheet presents hydrologic background information and an analysis of general water-quality properties and constituents, trace elements, and nutrients collected in water samples during low-flow synoptic sampling of the Gore Creek watershed. The U.S. Geological Survey also is conducting a study of the algae and macroinvertebrate communities and physical habitat of streams in the Gore Creek watershed during low flow. This study is designed to provide information about land-use and stream ecology relations in the watershed.

Colorado↗
USGS2021

Adaptive monitoring in action: Reconsidering design-based estimators reveals underestimation of whitebark pine disease prevalence in the Greater Yellowstone Ecosystem

Identifying and understanding status and trends in ecological indicators motivates continual monitoring over decades. Many programs rely on probability surveys and their companion design-based estimators for status assessments (e.g. Horvitz–Thompson). Design-based estimators do not easily extend to trend estimation nor situations with observation errors. Field-based monitoring efforts inevitably have turnover of field crew members which may affect consistency and accuracy of data collection over time. Additionally, design-based estimators ignore the complexities of spatial and temporal heterogeneity in an ecological indicator and how this variability may be linked to environmental or biological dynamics. We propose monitoring programs should re-evaluate their prescribed statistical methods, consider model-based approaches and adapt their sampling designs as needed to improve inferences. The Greater Yellowstone Ecosystem, home to two of the most iconic U.S. National Parks, has experienced significant declines in whitebark pine Pinus albicaulis communities due to forest pathogens, insect outbreaks, wildland fires and drought. Whitebark pine is a keystone species found in mountainous environments throughout the Western U.S. and Canada. We assessed the design-based ratio estimator originally recommended for estimating prevalence of white pine blister rust Cronartium ribicola . We compared the design-based estimator to a model-based approach that accounts for the sampling design, imperfect detection and allows for infection probabilities to vary over space and time. Ignoring observation errors led to lower estimated prevalence of white pine blister rust in the general population. Using model-based approaches, we found that the probability of infection has increased since 2004. However, overall prevalence likely has not changed because of the mountain pine beetle Dendroctonus ponderosae -induced shift towards smaller diameter trees that have a lower probability of infection compared to their larger cohorts. Synthesis and Applications . Using a design-based approach to detect change in ecological indicators falls short because of the inability to account for observation errors or to explore environmental or biological factors explaining temporal dynamics. Inherently understanding the mechanisms leading to changes in an ecological indicator over time informs potential management actions. Our assessment underscores the need for continued evaluation and updating of a monitoring program's sampling design and analytical procedures to maintain relevancy.

Wyoming↗
USGS2025

From subsidies to stressors: Shifting ecological baselines alter biological responses to nutrients in highly modified agricultural streams

Subsidy–stress gradients offer a useful framework for understanding ecological responses to perturbation and may help inform ecological metrics in highly modified systems. Historic, region-wide shifts from bottomland hardwood forest to row crop agriculture can cause positively skewed impact gradients in alluvial plain ecoregions, resulting in tolerant organisms that typically exhibit a subsidy response (increased abundance in response to environmental stressors) shifting to a stress response (declining abundance at higher concentrations). As a result, observed biological tolerance in modified ecosystems may differ from less modified regions, creating significant challenges for detecting biological responses to restoration efforts. Using the agriculturally dominated Mississippi Alluvial Plain (MAP) ecoregion in Mississippi, USA, as a case study, we tested the hypothesis that macroinvertebrate taxa that typically display a subsidy response to nutrient enrichment in less modified ecoregions (i.e., nutrient-tolerance) shift to a stress response to increasing nutrients in highly modified watersheds with elevated baseline nutrient conditions (i.e., nutrient intolerance). The abundance and diversity of MAP-specific intolerant taxa identified with threshold indicator taxa analysis were either unresponsive or exhibited a subsidy response to increasing nutrients in less modified ecoregions in Mississippi with less land alteration and lower nutrient concentrations, but declined at higher concentrations, providing evidence for a stress response to elevated nutrients in the MAP. Additionally, MAP-specific tolerant and intolerant taxa richness responded to increased nutrients predictably and consistently across space and time within the MAP. However, in MAP streams, elevated specific conductance was predicted to dampen the response of tolerant and intolerant taxa richness to increasing nutrient concentrations, highlighting the importance of considering multistressor interactions when interpreting biological data. Lastly, we demonstrate the efficacy of this approach with sediment bacterial communities characterized with amplicon sequencing, which lack sufficient life history characteristics necessary for the development of multimetric indices. Both macroinvertebrate and bacterial communities responded similarly to increasing nutrient concentrations, suggesting DNA-based approaches may provide an efficient biological assessment tool for monitoring water quality improvements in highly modified watersheds.

Mississippi↗
USGS2005

Geomorphic change and vegetation development on the Muddy River Mudflow Deposit

Geomorphic disturbances are widely recognized as important processes that influence plant-community development and landscape-scale vegetation patterns [e.g., Veblen and Ashton (1978), Garwood et al. (1979), Swanson et al. (1988), and Malanson (1993)]. In volcanically active areas such as the Pacific Northwest, mudflows are locally important geomorphic disturbance events governing short- and long-term ecological conditions. Volcanic mudflows can scour and inundate river valleys with large volumes of debris (Janda et al. 1981; Pierson 1985; Vallance and Scott 1997; Scott 1988; Vallance 2000; Kovanen et al. 2001) and influence plant succession tens of kilometers downstream from their points of origin (Halpern and Harmon 1983; Adams and Dale 1987;Wood and del Moral 1987; Frenzen et al. 1988). In addition to altering plant succession, large volcanic mudflows can initiate a cascading chain of secondary disturbances that further modify the landscape and affect subsequent ecological responses (see Swanson and Major, Chapter 3, this volume).

Book chapter↗
USGS2025

Where to restore and conserve? A regional benefit cost analysis of coral reef protection and restoration for coastal flood resilience

Momentum is growing for the management of coral reefs as a strategy to reduce climate risks in tropical coastlines. Yet, quantification of the life-time costs, impacts, and benefits remains limited. This study provides one of the first rigorous, spatially explicit, regional-scale Benefit:Cost Analyses (BCA) for coral reef restoration and was designed to meet the BCA requirements of major hazard mitigation funding and programs. This study simulates coastal flooding using a hydrodynamic model under different scenarios representing current coral reef conditions, reef degradation, and reef restoration. These coastal flood maps are used to estimate socioeconomic damages, which are included in a BCA to assess cost-effectiveness and priority areas for coral reef conservation and restoration. The United States Virgin Islands is used as a case study given recent impacts from storms and their new policy that declares reefs as natural infrastructure. The results show that flood risk across the islands of Saint Croix, Saint John, and Saint Thomas is $51.4 million USD per year. Annually, coral reefs prevent flood damages to 481 people and $43.6 million USD of infrastructure, which represents 87 % of the flood risk. These results identify the communities that could receive the greatest benefits from coral conservation and restoration, which overlap significantly. Coral reef restoration is found to be a cost-effective strategy for flood mitigation although how reefs are restored matters. Hybrid coral reef restoration provides greater flood mitigation benefits than ecological restoration, but its cost-effectiveness is overall lower given its greater costs. Many coastal areas have benefit:cost ratios exceeding 1.5, which complies with typical government agencies’ requirements for accessing hazard mitigation funds. This valuation framework helps provide rigorous regional-scale quantification of nature-based coastal protection solutions for coastal risk management decisions.

Journal of Environmental Management↗
USGS2011

Detection biases yield misleading patterns of species persistence and colonization in fragmented landscapes

Species occurrence patterns, and related processes of persistence, colonization and turnover, are increasingly being used to infer habitat suitability, predict species distributions, and measure biodiversity potential. The majority of these studies do not account for observational error in their analyses despite growing evidence suggesting that the sampling process can significantly influence species detection and subsequently, estimates of occurrence. We examined the potential biases of species occurrence patterns that can result from differences in detectability across species and habitat types using hierarchical multispecies occupancy models applied to a tropical bird community in an agricultural fragmented landscape. Our results suggest that detection varies widely among species and habitat types. Not incorporating detectability severely biased occupancy dynamics for many species by overestimating turnover rates, producing misleading patterns of persistence and colonization of agricultural habitats, and misclassifying species into ecological categories (i.e., forest specialists and generalists). This is of serious concern, given that most research on the ability of agricultural lands to maintain current levels of biodiversity by and large does not correct for differences in detectability. We strongly urge researchers to apply an inferential framework which explicitly account for differences in detectability to fully characterize species-habitat relationships, correctly guide biodiversity conservation in human-modified landscapes, and generate more accurate predictions of species responses to future changes in environmental conditions.

Las Cruces Biological Station↗
USGS2016

Total cylindrospermopsins, microcystins/nodularins, and saxitoxins data for the 2007 United States Environmental Protection Agency National Lake Assessment

Phytoplankton communities in freshwater lakes, ponds, and reservoirs may be dominated by cyanobacteria (also called blue-green algae) under certain environmental conditions. Cyanobacteria may cause a range of water-quality impairments, including the potential for toxin production. Cyanobacteria toxins (cyanotoxins) may adversely impact human and ecological health. Microcystins are considered to be one of the most commonly found classes of cyanotoxins in freshwater ecosystems, and as such were selected as a recreational indicator of water quality for the 2007 United States Environmental Protection Agency (EPA) National Lakes Assessment. However, much less is known about the occurrence of other classes of cyanotoxins in fresh surface water such as anatoxins, cylindrospermopsins, nodularins, and saxitoxins. The 2007 National Lakes Assessment followed a probabilistic study design and was directed by the EPA, in partnership with States, Tribes, and other federal agencies of the United States, to provide an assessment of water quality in the Nation’s lakes, ponds, and reservoirs based on trophic status, and ecological and recreational indicators. Integrated photic zone samples were collected by the EPA, U.S. Geological Survey (USGS), States, and Tribes in target water bodies, generally at their deepest point, and analyzed for microcystins by the U.S. Geological Survey. The USGS assisted with this survey by providing technical expertise and enzyme linked immunosorbent assay (ELISA) analysis of microcystins for all survey samples as an indicator for recreational water quality. A small subset of samples ( n =27) was analyzed by liquid chromatography tandem mass spectrometry (LC/MS/MS) by the USGS. Additionally, through partnership with the EPA National Health and Environmental Effects Research Laboratory (NHEERL), USGS analyzed all frozen samples by ELISA for two other classes of cyanotoxins, cylindrospermopsins and saxitoxins. Total cylindrospermopsins, microcystins, and saxitoxins were measured by enzyme-linked immunosorbent assay in a total of 1,331 samples from 1,161 lakes. Samples from this study had detection frequencies of 4.0, 32 (unweighted), and 7.6 percent, mean concentrations (detections only) of 0.56, 3.0, and 0.061 micrograms/L (μg/L), and maximum concentrations of 4.4, 230, and 0.38 μg/L for cylindrospermopsins, microcystins, and saxitoxins by ELISA, respectively in visit 1 and visit 2 samples. Microcystin ELISA results were categorized based on World Health Organization recreational surface-water guidelines for the relative probability of adverse health impacts because of microcystin exposure. The dataset described in this report is the first ever national reconnaissance of cyanotoxins in the United States. At least one microcystin congener was detected by LC/MS/MS in 52 percent of the 27 samples analyzed at a concentration greater than the LC/MS/MS minimum reporting level (MRL) of 0.010 μg/L and included detections for microcystin-LA, microcystin-LR, microcystin-LY, microcystin-RR, and microcystin-YR. Anatoxin-a, cylindrospermopsin, and nodularin-R were detected in 15 percent, 7 percent, and 4 percent of samples, respectively, at concentrations above 0.010 μg/L. Deoxycylindrospermopsin, domoic acid, lyngbyatoxin-a, microcystin-LF, microcystin-LW, and okadaic acid were not detected in the LC/MS/MS subset.

Data Series↗
USGS2022

Seasonal resource selection and movement ecology of free-ranging horses in the western United States

Understanding factors driving resource selection and habitat use of different species is an important component of management and conservation. Feral horses ( Equus caballus ) are free ranging across various vegetation types in the western United States, yet few studies have quantified their resource selection and seasonal use. We conducted a study to determine effects of vegetation community, distance to water, and topographic variables on seasonal resource selection in 2 feral horse populations in Great Basin sagebrush ( Artemisia spp.) ecosystems of west-central Utah, USA: Conger Herd Management Area (HMA) and Frisco HMA. We deployed global positioning system (GPS) radio-collars on 38 female horses and GPS-transmitters braided and glued into the tail hair of 14 males, collecting locations every 2 hours for 1–4 years between 2016 and 2020. We calculated home range size and core use area of social groups (harems) and bachelor males using auto-correlated kernel density estimators for each biologically defined season (breeding, fall, and winter) per study year. We examined seasonal home range size and overlap of harem groups and bachelor males and compared movement speed of bachelors and harems among seasons. We determined seasonal resource selection in a use-availability framework using resource selection functions. We hypothesized that horses would select for areas of high herbaceous vegetation, that water would be a key variable in resource selection models like other equids, and home range size in winter would be largest because horses can eat snow for hydration and could therefore roam farther from surface water. Mean annual home range size was 103.12 ± 37.38 km 2 (SD) for Conger harems and 117.47 ± 32.75 km 2 for Frisco harems. At Conger there was no difference in home range size between harem groups and bachelor males, but home range size was smaller in winter than other seasons, whereas winter home range size at Frisco was larger than other seasons. Bachelor males moved at higher speeds than harems during all seasons, and harem groups from both populations had lower movement speeds in winter. Harem groups had distinct winter ranges with little overlap on breeding season ranges. In both populations, all horses selected for herbaceous vegetation types and avoided forest relative to shrubland throughout the year. Harems at Frisco were consistently located closer to water sources, whereas selection for water sources by Conger harems varied seasonally, with winter having the lowest selection. Harem groups at Conger had an average of 10.6% of their home ranges outside the HMA boundary and Frisco harems had up to 66.8% outside, likely because of the horseshoe shape of Frisco HMA in which shrub meadows (foraging areas) comprise the horseshoe center, which is outside the HMA. Our results highlight the importance of water sources, which were a key predictor of horse movement patterns in our study. We emphasize the utility of telemetry devices to understand resource selection of feral horses at a fine scale, enabling management to be more targeted and facilitate planning.

Utah↗
USGS2021

Gulf of Mexico blue hole harbors high levels of novel microbial lineages

Exploration of oxygen-depleted marine environments has consistently revealed novel microbial taxa and metabolic capabilities that expand our understanding of microbial evolution and ecology. Marine blue holes are shallow karst formations characterized by low oxygen and high organic matter content. They are logistically challenging to sample, and thus our understanding of their biogeochemistry and microbial ecology is limited. We present a metagenomic and geochemical characterization of Amberjack Hole on the Florida continental shelf (Gulf of Mexico). Dissolved oxygen became depleted at the hole’s rim (32 m water depth), remained low but detectable in an intermediate hypoxic zone (40–75 m), and then increased to a secondary peak before falling below detection in the bottom layer (80–110 m), concomitant with increases in nutrients, dissolved iron, and a series of sequentially more reduced sulfur species. Microbial communities in the bottom layer contained heretofore undocumented levels of the recently discovered phylum Woesearchaeota (up to 58% of the community), along with lineages in the bacterial Candidate Phyla Radiation (CPR). Thirty-one high-quality metagenome-assembled genomes (MAGs) showed extensive biochemical capabilities for sulfur and nitrogen cycling, as well as for resisting and respiring arsenic. One uncharacterized gene associated with a CPR lineage differentiated hypoxic from anoxic zone communities. Overall, microbial communities and geochemical profiles were stable across two sampling dates in the spring and fall of 2019. The blue hole habitat is a natural marine laboratory that provides opportunities for sampling taxa with under-characterized but potentially important roles in redox-stratified microbial processes.

Interational Society of Microbial Ecology (ISME) J↗
USGS2025

Understanding predator-prey-competitor dynamics between Lower Missouri River Macrhybopsis and Scaphirhynchus using a population—bioenergetics model ensemble

The pallid sturgeon Scaphirhynchus albus is a long-lived, endangered fish in the Missouri River. Individuals become piscivorous as adults, so recruitment from stocking or reproduction could reduce populations of prey, including Macrhybopsis chubs. We constructed an individual- and age-based, multi-species, predator-prey-competitor model (IAMP) to represent the benthic community (sturgeons, chubs, and chironomids) of the Lower Missouri River (LMR) to explore scenarios of potential predator-prey-competitor dynamics. Our simulations suggest that chubs alone are unlikely able to support a level of LMR pallid sturgeon similar to historical or current populations. These simulations also suggest that adult pallid sturgeon may need to shift to non-chub prey fish to achieve the greater sizes observed in the Upper Missouri River. When annual hydrologic regimes were included, we found a negative relationship between chub relative abundance and previous year 30-day minimum flows. Inclusion of temporal environmental variability made it clear that large chub populations may be necessary to support LMR pallid sturgeon. When full stochasticity was included in the IAMP, chub population sizes needed to increase further to ensure continued reproduction and recruitment of both chubs and pallid sturgeon. These results support the hypothesis that the pallid sturgeon population in the Lower Missouri River may be food-limited. However, the full extent of this limitation and the management changes needed to address this will require more research on the biology and population dynamics of this fish community, on pallid sturgeon interactions with prey species, and on how sympatric species may be affected during the pallid sturgeon recovery process.

Colorado, Kansas, Minnesota, Missouri, Montana, Ne↗
USGS2010

Modelling community dynamics based on species-level abundance models from detection/nondetection data

1. In large‐scale field surveys, a binary recording of each species’ detection or nondetection has been increasingly adopted for its simplicity and low cost. Because of the importance of abundance in many studies, it is desirable to obtain inferences about abundance at species‐, functional group‐, and community‐levels from such binary data. 2. We developed a novel hierarchical multi‐species abundance model based on species‐level detection/nondetection data. The model accounts for the existence of undetected species, and variability in abundance and detectability among species. Species‐level detection/nondetection is linked to species‐level abundance via a detection model that accommodates the expectation that probability of detection (at least one individuals is detected) increases with local abundance of the species. We applied this model to a 9‐year dataset composed of the detection/nondetection of forest birds, at a single post‐fire site (from 7 to 15 years after fire) in a montane area of central Japan. The model allocated undetected species into one of the predefined functional groups by assuming a prior distribution on individual group membership. 3. The results suggest that 15–20 species were missed in each year, and that species richness of communities and functional groups did not change with post‐fire forest succession. Overall abundance of birds and abundance of functional groups tended to increase over time, although only in the winter, while decreases in detectabilities were observed in several species. 4. Synthesis and applications . Understanding and prediction of large‐scale biodiversity dynamics partly hinge on how we can use data effectively. Our hierarchical model for detection/nondetection data estimates abundance in space/time at species‐, functional group‐, and community‐levels while accounting for undetected individuals and species. It also permits comparison of multiple communities by many types of abundance‐based diversity and similarity measures under imperfect detection.

Journal of Applied Ecology↗
USGS2006

Community maturity, species saturation and the variant diversity- productivity relationships in grasslands

Detailed knowledge of the relationship between plant diversity and productivity is critical for advancing our understanding of ecosystem functioning and for achieving success in habitat restoration efforts. However, effects and interactions of diversity, succession and biotic invasions on productivity remain elusive. We studied newly established communities in relation to preexisting homogeneous vegetation invaded by exotic plants in the northern Great Plains, USA, at four study sites for 3 years. We observed variant diversity-productivity relationships for the seeded communities (generally positive monotonic at three sites and non-monotonic at the other site) but no relationships for the resident community or the seeded and resident communities combined at all sites and all years. Community richness was enhanced by seeding additional species but productivity was not. The optimal diversity (as indicated by maximum productivity) changed among sites and as the community developed. The findings shed new light on ecosystem functioning of biodiversity under different conditions and have important implications for restoration. ?? 2006 Blackwell Publishing Ltd/CNRS.

Ecology Letters↗
USGS2009

Multi-state succession in wetlands: a novel use of state and transition models

The complexity of ecosystems and mechanisms of succession are often simplified by linear and mathematical models used to understand and predict system behavior. Such models often do not incorporate multivariate, nonlinear feedbacks in pattern and process that include multiple scales of organization inherent within real-world systems. Wetlands are ecosystems with unique, nonlinear patterns of succession due to the regular, but often inconstant, presence of water on the landscape. We develop a general, nonspatial state and transition (S and T) succession conceptual model for wetlands and apply the general framework by creating annotated succession/management models and hypotheses for use in impact analysis on a portion of an imperiled wetland. The S and T models for our study area, Water Conservation Area 3A South (WCA3), Florida, USA, included hydrologic and peat depth values from multivariate analyses and classification and regression trees. We used the freeware Vegetation Dynamics Development Tool as an exploratory application to evaluate our S and T models with different management actions (equal chance [a control condition], deeper conditions, dry conditions, and increased hydrologic range) for three communities: slough, sawgrass ( Cladium jamaicense ), and wet prairie. Deeper conditions and increased hydrologic range behaved similarly, with the transition of community states to deeper states, particularly for sawgrass and slough. Hydrology is the primary mechanism for multi-state transitions within our study period, and we show both an immediate and lagged effect on vegetation, depending on community state. We consider these S and T succession models as a fraction of the framework for the Everglades. They are hypotheses for use in adaptive management, represent the community response to hydrology, and illustrate which aspects of hydrologic variability are important to community structure. We intend for these models to act as a foundation for further restoration management and experimentation which will refine transition and threshold concepts.

Florida↗
USGS2004

Rapid assessment indicator of wetland integrity as an unintended predictor of avian diversity

Rapid assessment of aquatic ecosystems has been widely implemented, sometimes without thorough evaluation of the robustness of rapid assessment metrics as indicators of ecological integrity. Here, we evaluate whether the Ohio Rapid Assessment Method (ORAM) for Wetlands Version 5.0 is a useful indicator of ecological integrity beyond its intended purpose. ORAM was developed to categorize natural wetlands for regulatory purposes and to contribute to the development of indicators of biotic integrity. It was never intended for use as an index of the quality of habitat for wetland birds. Nonetheless, it is conceivable that ORAM scores could serve as adequate predictors of avian diversity. We evaluated whether avian species richness in wetlands could be reliably predicted from each of the following variables: (1) total ORAM score, (2) total score minus the score for one metric that did not apply to all wetlands, and (3) sum of scores for the four ORAM components (of 16 scored) with the highest potential point total. These four components corresponded to aquatic vegetation communities, microtopography, modifications to natural hydrologic regime, and sources of water. All three variables were significant predictors of both total species richness and mean species richness of birds of conservation concern. Variable (3) was a significant predictor of mean species richness of wetland-dependent birds. Variable (2) was a weak predictor of both total and mean species richness of all birds combined. These results extend the robustness of ORAM as an indicator of the ecological integrity of wetlands.

Hydrobiologia↗
USGS2018

Terrestrial fauna are agents and endpoints in ecosystem restoration following dam removal

Dam removal is an effective and increasingly applied river restoration strategy. This has led to heightened calls for research and monitoring aimed at understanding physical and ecological outcomes following dam removal. While such research programs have increased, roles of terrestrial fauna in the restoration process remain poorly understood, although wildlife and invertebrate fauna are key components of restored ecosystems. Wildlife play reciprocal roles in restoration: they benefit from restored habitats and their activities affect restoration trajectories. Dam removal exposes substrates on former reservoirs and reconnects river corridors, providing new habitat and food resources for terrestrial fauna. Conversely, many wildlife may influence the river restoration process, with both short-term and long-term consequences for community composition, nutrient transfer, and ecosystem function. We assert that considering terrestrial fauna more directly in river restoration research and planning can enhance restoration outcomes. We illustrate these concepts by describing short-term patterns and potential future processes expected from the recent removal of two large dams on the Elwha River in Washington State, the largest dam removal effort ever undertaken. We conclude that an ecosystem-level understanding of restoration following dam removal is critical to fully assessing the impacts and benefits of restoration. This includes measuring the roles and responses of terrestrial fauna to these ecologically and culturally significant restoration projects.

Ecological Restoration↗
USGS2002

Water quality and aquatic communities of upland wetlands, Cumberland Island National Seashore, Georgia, April 1999 to July 2000

Cumberland Island is the southernmost and largest barrier island along the coast of Georgia. The island contains about 2,500 acres of freshwater wetlands that are located in a variety of physical settings, have a wide range of hydroperiods, and are influenced to varying degrees by surface and ground water, rainwater, and seawater. In 1999-2000, the U.S. Geological Survey, in cooperation with the National Park Service, conducted a water-quality study of Cumberland Island National Seashore to document and interpret the quality of a representative subset of surface- and ground-water resources for management of the seashore's natural resources. As part of this study, historical ground-water, surface-water, and ecological studies conducted on Cumberland Island also were summarized. Surface-water samples from six wetland areas located in the upland area of Cumberland Island were collected quarterly from April 1999 to March 2000 and analyzed for major ions, nutrients, trace elements, and field water-quality constituents including specific conductance, pH, temperature, dissolved oxygen, alkalinity, tannin and lignin, and turbidity. In addition, water temperature and specific conductance were recorded continuously from two wetland areas located near the mean high-tide mark on the Atlantic Ocean beaches from April 1999 to July 2000. Fish and invertebrate communities from six wetlands were sampled during April and December 1999. The microbial quality of the near-shore Atlantic Ocean was assessed in seawater samples collected for 5 consecutive days in April 1999 at five beaches near campgrounds where most recreational water contact occurs. Ground-water samples were collected from the Upper Floridan aquifer in April 1999 and from the surficial aquifer in April 2000 at 11 permanent wells and 4 temporary wells (drive points), and were analyzed for major ions, nutrients, trace elements, and field water-quality constituents (conductivity, pH, temperature, dissolved oxygen, and alkalinity). Fecal-coliform bacteria concentrations were measured, but not detected, in samples collected from two domestic water-supply wells. During the 12-month period from April 1999 to March 2000 when water-quality and aquatic-community samples were collected, rainfall was 12.93 inches below the 30-year average rainfall. Constituent concentrations were highly variable among the different wetlands during the study period. Rainfall and tidal surges associated with tropical storms and hurricanes substantially influenced water quantity and quality, particularly in wetland areas directly influenced by tidal surges. Although surface waters on Cumberland Island are not used as sources of drinking water, exceedances of U.S. Environmental Protection Agency primary and secondary standards for drinking water were noted for comparative purposes. A nitrate concentration of 12 milligrams per liter in one sample from Whitney outflow was the only exceedance of a maximum contaminant level. Secondary standards were exceeded in 26 surface-water samples for the following constituents: pH (10 exceedances), chloride (8), sulfate (5), total dissolved solids (4), iron (2), fluoride (1), and manganese (1). The total-dissolved-solids concentrations and the relative abundance of major ions in surface-water samples collected from wetlands on Cumberland Island provide some insight into potential sources of water and influences on water quality. Major-ion chemistries of water samples from Whitney Lake, Willow Pond, and South End Pond 3 were sodium-chloride dominated, indicating direct influence from rainwater, salt aerosol, or inundation of marine waters. The remaining wetlands sampled had low total-dissolved-solids concentrations and mixed major-ion chemistries--North Cut Pond 2A was magnesium-sodium-chloride-sulfate dominated and Lake Retta and the two beach outflows were sodium-calcium-bicarbonate-chloride dominated. The higher percent calcium and bicarbonate in some wetlands sugg

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