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Results for “Ecological Restoration”

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At least 1,459 records · Page 81Linked to original sources
USGS2017

Advancing mangrove macroecology

Mangrove forests provide a wide range of ecosystem services to society, yet they are among the most anthropogenically impacted coastal ecosystems in the world. In this chapter, we discuss and provide examples for how macroecology can advance our understanding of mangrove ecosystems. Macroecology is broadly defined as a discipline that uses statistical analyses to investigate large-scale, universal patterns in the distribution, abundance, diversity, and organization of species and ecosystems, including the scaling of ecological processes and structural and functional relationships. Macroecological methods can be used to advance our understanding of how non-linear responses in natural systems can be triggered by human impacts at local, regional, and global scales. Although macroecology has the potential to gain knowledge on universal patterns and processes that govern mangrove ecosystems, the application of macroecological methods to mangroves has historically been limited by constraints in data quality and availability. Here we provide examples that include evaluations of the variation in mangrove forest ecosystem structure and function in relation to macroclimatic drivers (e.g., temperature and rainfall regimes) and climate change. Additional examples include work focused upon the continental distribution of aboveground net primary productivity and carbon storage, which are rapidly advancing research areas. These examples demonstrate the value of a macroecological perspective for the understanding of global- and regional-scale effects of both changing environmental conditions and management actions on ecosystem structure, function, and the supply of goods and services. We also present current trends in mangrove modeling approaches and their potential utility to test hypotheses about mangrove structural and functional properties. Given the gap in relevant experimental work at the regional scale, we also discuss the potential use of mangrove restoration and rehabilitation projects as macroecological studies that advance the critical selection and conservation of ecosystem services when managing mangrove resources. Future work to further incorporate macroecology into mangrove research will require a concerted effort by research groups and institutions to launch research initiatives and synthesize data collected across broad biogeographic regions.

Book chapter↗
USGS2021

Modeling structural mechanics of oyster reef self-organization including environmental constraints and community interactions

Self-organization is a process of establishing and reinforcing local structures through feedbacks between internal population dynamics and external factors. In reef-building systems, substrate is collectively engineered by individuals that also occupy it and compete for space. Reefs are constrained spatially by the physical environment, and by mortality, which reduces production but exposes substrate for recruits. Reef self-organization therefore depends on efficient balancing of production and occupancy of substrate. To examine this, we develop a three-dimensional individual-based model (IBM) of oyster reef mechanics. Shell substrate is grown by individuals as valves, accumulates at the reef level, and degrades following mortality. Single restoration events and subsequent dynamics are simulated for a case study in South Carolina (USA). Variability in model processes is included on recruitment, spatial environmental constraints, and predation, over multiple independent runs and five predator community scenarios. The main goal for this study is to summarize trends in dynamics that are robust across this uncertainty, and from these generate new hypotheses and predictions for future studies. Simulation results demonstrate three phases following restoration: initial transient dynamics with considerable shell loss, followed by growth and saturation of the live population, and then saturation of settlement habitat several years later. Over half of simulations recoup initial shell losses as populations grow, while others continue in decline. The balance between population density, substrate supporting the reef, and exposed surfaces for settlement is mediated by overall population size and size structure, presence of predators, and relative amounts of live individuals and intact dead shells. The efficiency of settlement substrate production improves through time as population size structure becomes more complex, and the population of dead valves accumulates.

Ecological Modelling↗
USGS2017

Selecting focal species as surrogates for imperiled species using relative sensitivities derived from occupancy analysis

Most imperiled species are rare or elusive and difficult to detect, which makes gathering data to estimate their response to habitat restoration a challenge. We used a repeatable, systematic method for selecting focal species using relative sensitivities derived from occupancy analysis. Our objective was to select suites of focal species that would be useful as surrogates when predicting effects of restoration of habitat characteristics preferred by imperiled species. We developed 27 habitat profiles that represent general habitat relationships for 118 imperiled species. We identified 23 regularly encountered species that were sensitive to important aspects of those profiles. We validated our approach by examining the correlation between estimated probabilities of occupancy for species of concern and focal species selected using our method. Occupancy rates of focal species were more related to occupancy rates of imperiled species when they were sensitive to more of the parameters appearing in profiles of imperiled species. We suggest that this approach can be an effective means of predicting responses by imperiled species to proposed management actions. However, adequate monitoring will be required to determine the effectiveness of using focal species to guide management actions.

Alabama↗
USGS1999

Flooding and fish diversity in a reclaimed river-wetland

Attempts at large river restoration are few and largely experimental. We studied a newly constructed river-wetland project on the upper Mississippi River three years after its completion. Species inventories for fish began to be compiled in the spring of 1993. Coincidentally, record rainfall throughout the midwest resulted in extreme floods and caused flooding of the study area during 1993. Fish communities responded to flooding with increased species diversity immediately following the flood. Wetland habitats yielded eight species of fish prior to flooding in June of 1993 compared to 26 species collected at the same sites in August 1993 following the flood crest. June 1994 sampling caught 33 species, but they declined to 16 in subsequent collections during August 1994. Flooding served to provide at least a temporary increase in diversity.

Journal of Freshwater Ecology↗
USGS2026

Basal area loss from fire using field-calibrated remote sensing refines western US fire severity measurements

The spatial patterns of fire effects and tree mortality have profound consequences for forest resilience. Cost-effective, medium-resolution, and spatiotemporally extensive fire severity measurements are essential for informing post-fire restoration and improving our understanding of wildfires—from forest stands to continents and from days to decades. Remote sensing advancements have improved burn severity mapping, but methods vary in interpretability, scalability, generalizability, and alignment with field measurements. One meaningful metric of fire effects on forests is proportion basal area loss, but existing methods are limited by a lack of region-specific field reference data and a scalable mapping framework. To address these issues, we compiled 3280 field reference plots from 123 fires in forests across the Western US to calculate the proportion of fire-induced basal area loss. We then used spatially cross-validated machine learning models with concurrent hyperparameter tuning to select a skillful, parsimonious model from a large candidate set of remotely-sensed, climatic, and topographic predictors. Spectral-only measures of severity over- or underestimated basal area loss in dry versus wet years and across aspects, demonstrating the value of incorporating climatic and topographic context. We also tested model performance on a separate holdout dataset in the Southwest US as a demonstration of reproducibility and transparency. We provide a Google Earth Engine tool for estimating proportional basal area loss for any fire perimeter in the Western US, enabling rapid map creation for land management and ecological modeling. All code, model parameters, and training data are released to support reproducibility, community adoption, regional refinement, and adaptation to new regions.

western United States↗
USGS2021

Larval Coregonus spp. diets and zooplankton community patterns in the Apostle Islands, Lake Superior

With the exception of lake whitefish ( Coregonus clupeaformis ), relatively little is known about the early life history of larval coregonines in the Laurentian Great Lakes. For example, our knowledge of the feeding ecology of larval coregonines (excluding lake whitefish) is based on only 900 stomachs reported in the literature. Here, we describe the diets and demographics of larval coregonines from ice-out to late July, and the contemporaneous zooplankton community, in the Apostle Islands region of Lake Superior in 2018. Exogenous feeding was evident among the smallest larvae (down to 6 mm). Percent of larvae with food in their stomachs increased and yolk reserves decreased as larvae grew from 10 to 13 mm. A majority of the diet (58%) was copepod nauplii, with generally positive selection for adult copepods and Holopedium . The patterns in exogenous feeding and yolk sac absorption were similar to observations in Lake Superior in the 1970s. Diets were also generally similar, although Limnocalanus , Holopedium , and zooplankton eggs were more prevalent in 2018 than the 1970s. Demographic data suggested at least two distinct cohorts and/or coregonine species in 2018. Post-hoc genetic testing of larvae in a parallel study suggested our samples comprised a mix of predominantly cisco ( C. artedi ), kiyi ( C. kiyi ), and bloater ( C. hoyi ). Early life history studies, when coupled with emerging genetic techniques that can identify larval coregonines to species, will provide a powerful combination to better understand population dynamics of coregonines at a time of ongoing restoration and rehabilitation efforts throughout the Great Lakes.

Apostle Islands, Lake Superior↗
USGS2023

Spatiotemporal variations in copper, arsenic, cadmium, and zinc concentrations in surface water, fine-grained bed sediment, and aquatic macroinvertebrates in the upper Clark Fork Basin, western Montana—A 20-year synthesis, 1996–2016

The legacy of mining-related contamination in the upper Clark Fork Basin created an extensive longitudinal gradient in metal concentrations, extending from Silver Bow Creek to Lake Pend Oreille, Idaho. Downstream metal concentrations continue to decline, but, despite such improvements, the ecological health of much of the river remains uncertain. Understanding the long-term consequences of the Clark Fork River mining legacy may be supported by environmental monitoring techniques that include a holistic assessment of biological health or response to define organism exposure to complex contaminant mixtures and the consequences of such exposures. This report presents the spatiotemporal patterns of mining-related contaminants, copper, arsenic, cadmium, and zinc, in surface water, fine-grained bed sediment, and macroinvertebrate (aquatic insect) tissue in the upper Clark Fork from near Butte to Missoula, Montana. Overall, the patterns in water column sample concentrations observed in this study were consistent with previously observed trends, but bed sediment concentrations and concentrations of copper and arsenic varied more in tissue samples among sites. Trace element concentrations, especially copper, often exceeded the chronic aquatic life criteria and consistently exceeded the sediment probable effects level PEL for copper, particularly in the upper and middle river segments. The 20 years considered here were the wettest period since remediation started, and this increase in precipitation may have affected patterns in contaminant concentrations. Results of this study demonstrated the utility of a continued, comprehensive biomonitoring program to help guide and evaluate future environmental cleanup activities in the Clark Fork. Despite variation in defining complete restoration in these watersheds, using multiple lines of evidence in this study provided quantifiable measures of the timing and completeness of recovery relative to reference conditions. Successful recovery in the Clark Fork may benefit from an adaptive management strategy to continue collecting a comprehensive, multivariate dataset to evaluate whether established goals are being met and for subsequent adjustments and management, as needed.

Montana↗
USGS2018

Behavior and reproductive ecology of the Sicklefin Redhorse: An imperiled southern Appalachian Mountain fish

Many nongame fishes are poorly understood but are essential to maintaining healthy aquatic ecosystems globally. The undescribed Sicklefin Redhorse Moxostoma sp. is a rare, imperiled, nongame fish endemic to two southern Appalachian Mountain river basins. Little is known of its behavior and ecology, but this information is urgently needed for conservation planning. We assessed the spatial and temporal bounds of spawning migration, quantified seasonal weekly movement patterns, and characterized seasonal and spawning behavior using radiotelemetry and weir sampling in the Hiwassee River basin, North Carolina–Georgia, during 2006 and 2007. Hiwassee River tributaries were occupied predominantly during the fish's spawning season, lower reaches of the tributaries and the Hiwassee River were primarily occupied during the postspawning season (i.e., summer and fall), and lower lotic reaches of Hiwassee River (upstream from Hiwassee Lake) were occupied during winter. Adults occupied Hiwassee Lake only as a movement corridor during spawning migrations. Both sexes conducted upstream spawning migrations simultaneously, but males occupied spawning tributaries longer than females. Sicklefin Redhorse exhibited interannual spawning‐area and tributary fidelity. Cold water temperatures associated with hypolimnetic releases from reservoirs and meteorological conditions influenced spawning migration distance and timing. During 2007, decreased discharges during the spawning season were associated with decreases in migration distance and spawning tributary occupancy duration. Foraging was the dominant behavior observed annually, followed by reproductive behaviors (courting and spawning) during the spawning season. No agonistic reproductive behavior was observed, but females exhibited a repetitious postspawning digging behavior that may be unique in the family Catostomidae. Our findings suggest that protection and restoration of river continuity, natural flow regimes, seasonally appropriate water temperatures, and geographic range expansion are critical components to include in Sicklefin Redhorse conservation planning. Fisheries and ecosystem managers can use our findings to justify sensitive management decisions that conserve and restore critical streams and rivers occupied by this imperiled species.

Hiwassee River↗
USGS2024

Patterns of marsh surface accretion rates along salinity and hydroperiod gradients between active and inactive coastal deltaic floodplains

High subsidence rates are inherent to coastal deltas worldwide, contributing to rapid rates of relative sea-level rise and compromising the sustainability of coastal wetlands. Different parts of river deltas, however, experience accretion or erosion, depending on the coupling between ecological and morphological processes. Wetland expansion occurs in active deltaic coastal basins that are connected to riverine sedimentation. In contrast, wetland degradation occurs in inactive deltaic coastal basins where river engineering strategies associated with flood control restrict river connectivity. Here, we investigated the relative role of inorganic and organic loading to marsh accretion rates spanning fresh to brackish to saline zones between active and inactive coastal deltaic floodplains of the Mississippi River Delta. Marsh surface accretion rates monitored over 36 months using the feldspar marker horizon technique ranged from 1.24 ± 0.35 cm yr −1 in the freshwater marsh to 2.94 ± 0.51 cm yr −1 in the saline marsh in the inactive coastal basin compared to an opposite trend in the active coastal basin with a low vertical accretion rate in the saline site at 1.12 ± 0.17 cm yr −1 and higher accretion values at the freshwater site (2.14 ± 0.49 cm yr −1 ). Our results suggest that saline marshes have high resilience identified by high vertical accretion rates exceeding those of river-dominated freshwater marshes in active deltaic floodplains. Overall, the marsh surface accretionary patterns detected in this study underscores the relative contribution of organic and inorganic sediments to elevation capital across salinity gradients between active and inactive basins in coastal Louisiana with particular interest to river management and restoration strategies. These findings, however, are applicable to coastal deltaic floodplains elsewhere given the repetition geomorphic forcings (e.g., relative contribution of riverine, tidal and wave power) and coastal typologies worldwide.

Estuarine, Coastal, and Shelf Science↗
USGS2025

Biological implications for contaminants of emerging concern in the Great Lakes–Upper St Lawrence River drainage: An effect-based ecological hazard assessment in fish

Contaminants of emerging concern (CECs) are released widely and continuously into the Great Lakes Basin–Upper St Lawrence River study area, with many detected in surface water at concentrations known to adversely affect fish. We applied a recent ecological hazard assessment methodology to identify the biological significance of a database of 21,441 surface water CEC concentrations compiled from 7,162 surface water samples collected at 1,021 sampling sites in 387 individual waterbodies throughout the Great Lakes Basin. We assessed hazard to fish in 12 effect categories (e.g., mortality, developmental, reproductive) from aqueous exposure to 16 emerging contaminants. Our hazard assessment used pairs of screening values to generate contaminant- and effect-specific ordinal hazard scores. Using this novel methodology, we generated a database of 93,864 hazard scores. We found the highest level of hazard to fish, indicating probable adverse impacts, was broadly distributed and often associated with municipalities. Mortality, reproductive, and developmental effect categories combined accounted for 17.5% of high hazard observations. Low hazard, indicating possible adverse effects, was prevalent for numerous effect categories and occurred throughout the period 1991–2021. For mortality, reproductive, and developmental effect categories, the incidence of elevated hazard (low or high hazard) among assessed water samples was 20.4%, 39.5%, and 20.3%, respectively. On a local scale, effect-based assessment is an efficient and conceptually simple tool for natural resource managers to obtain effect- and site-specific hazard information concerning CEC effects in fish that can be used in project planning and results interpretation for natural resource monitoring, restoration, and protection.

Great Lakes–Upper St Lawrence River study area↗
USGS2019

Factors affecting prey availability and habitat usage of nonbreeding piping plovers (Charadrius melodus) in coastal Louisiana

The Gulf of Mexico is home to a large proportion of the wintering population of the threatened piping plover ( Charadrius melodus ), but little is known about the bird's ecology in this region. In Louisiana, the majority of nonbreeding piping plovers are found on the state's rapidly eroding barrier islands. Between August 2013 and May 2014, surveys were conducted to assess the abundance and habitat use of piping plovers, as well as to characterize their invertebrate prey base, on Whiskey and Trinity islands. Seventy-eight percent of piping plovers observed were foraging, 18% roosting, and 4% engaged in other ambulatory activities. Intertidal habitat, such as foreshore beach and tidal flats, was used by 87% of foraging and 96% of roosting piping plovers. Though available, backshore beach, interior sand flats, and dunes were rarely used. The invertebrate community was dominated by haustoriid amphipods (87.5% of individuals collected), followed by bivalves (9.3%) and polychaetes (2.7%). Seasonal patterns and between-island differences were observed in all three invertebrate taxa, but these effects differed between beach habitat and the gulfside and bayside of prominent sand spits. Moisture had a positive effect on amphipod abundance and polychaete presence. There was no association between invertebrate and plover abundance, and prey abundance did not differ between sample sites where piping plovers were observed foraging and random sites. The low abundances of birds and prey, coupled with high variation among samples, are challenges for establishing baseline datasets to evaluate the consequences of coastal restoration activities.

Louisiana↗
USGS2023

Seasonal spatial ecology of Lake Trout in Lake Erie

Objective Lake Trout Salvelinus namaycush are native coldwater apex predators that play an important role in maintaining ecosystem functionality and diversity in the Laurentian Great Lakes. Following population collapses, rehabilitation efforts were widely initiated in the Great Lakes to reestablish self‐sustaining Lake Trout populations. Lake Erie may pose a challenge to these rehabilitation efforts due to limited availability of appropriate oxythermal habitat. Our goal was to investigate seasonal habitat use of adult Lake Trout in Lake Erie to inform management and rehabilitation efforts. Methods We used acoustic telemetry in Lake Erie, which was equipepd with a lake‐wide acoustic receiver grid, to quantify Lake Trout seasonal region occupancy, dispersal distances, bottom depth occupancy, space use extent, and space use overlap. Result We found that 32% of fish tagged in the eastern basin and all fish from the western basin dispersed more than 100 km from their tagging location, which represents a greater proportion of the population moving long distances than what has been previously documented in the Great Lakes. During stratification, Lake Trout were detected almost exclusively in the offshore eastern basin in areas where water depth exceeded 25 m. During nonstratified seasons, fish used other regions of the lake, occupying areas of highly variable depths. During fall, most fish tagged in the eastern basin occupied habitat along the southern shore of the eastern basin. Fish tagged in the western basin returned to this region in the fall of subsequent years despite occupying the offshore eastern basin during stratification and having depth occupancy, home range size, and overlap similar to that of eastern basin‐tagged fish. Fish size was positively correlated with receiver depth during winter and spring, and with home range overlap during spring and summer. Conclusion The results of this study can begin to inform management decisions regarding stocking locations, harvest regulations, and habitat restoration to facilitate the continued rehabilitation of this important native species.

Lake Erie↗
USGS2022

Effects of warming winter embryo incubation temperatures on larval cisco (Coregonus artedi) survival, growth, and critical thermal maximum

Freshwater whitefishes, Salmonidae Coregoninae, are cold stenothermic fishes of ecological and socio-economic importance in northern hemisphere lakes that are warming in response to climate change. To address the effect of warming waters on coregonine reproduction we experimentally evaluated different embryo incubation temperatures on post-hatching survival, growth, and critical thermal maximum of larval cisco ( Coregonus artedi ) sampled from lakes Superior and Ontario. Embryos were incubated at water temperatures of 2.0, 4.4, 6.9, and 8.9 °C to simulate present and increased winter temperatures, and hatched larvae were reared in a common environment. For the populations from both lakes, larval survival and critical thermal maximum were negatively related to incubation temperature, and larval growth was positively related to incubation temperature. The magnitude of change across incubation temperatures was greater in the population sampled from Lake Superior than Lake Ontario for all traits examined. The more rapid decrease in survival and critical thermal maximum across incubation temperatures for larval cisco in Lake Superior, compared to those from Lake Ontario, suggests that Lake Superior larvae may possess a more limited ability to acclimate to and cope with increasing winter water temperatures. However, the rapid increase in growth rates across incubation temperatures in Lake Superior larvae suggests they could recover better from hatching at a small length induced by warm winters, as compared to Lake Ontario larvae. Our results suggest propagation and restoration programs may want to consider integrating natural habitat preferences and maximizing phenotypic variability to ensure offspring are set up for success upon stocking.

Lake Ontario, Lake Superior↗
USGS2024

Systematic process for determining field-sampling effort required to know vegetation changes in large, disturbed rangelands where management treatments have been applied

Adequate numbers of replicated, dispersed, and random samples are the basis for reliable sampling inference on resources of concern, particularly vegetation cover across large and heterogenous areas such as rangelands. Tools are needed to predict and assess data precision, specifically the sampling effort required to attain acceptable levels of precision, before and after sampling. We describe and evaluate a flexible and scalable process for assessing the sampling effort requirement for a common monitoring context (responses of rangeland vegetation cover to post-fire restoration treatments), using a custom R script called “SampleRange.” In SampleRange, vegetation cover is estimated from available digital-gridded or field data (e.g., using the satellite-derived cover from the Rangeland Assessment Platform). Next, the sampling effort required to estimate cover with 20% relative standard error (RSE) or to saturate sampling effort is determined using simulations across the environmental gradients in areas of interest to estimate the number of needed plots (“SampleRange quota”). Finally, the SampleRange quota are randomly identified for actual sampling. A 2022 full-cycle trial of SampleRange using the best available digital and prior field data for areas treated after a 2017 wildfire in sagebrush-steppe rangelands revealed that differences in the predicted compared with realized RSEs are inevitable. Future efforts to account for uncertainty in remotely sensed−based vegetative products will enhance tool utility.

Rangeland Ecology and Management↗
USGS2023

Influence of increased freshwater inflow on nitrogen and phosphorus budgets in a dynamic subtropical estuary, Barataria Basin, Louisiana

Coastal Louisiana is currently experiencing high rates of wetland loss and large-scale ecosystem restoration is being implemented. One of the largest and most novel restoration projects is a controlled sediment diversion, proposed to rebuild and sustain wetlands by diverting sediment- and nutrient-rich water from the Mississippi River. However, the impact of this proposed sediment diversion on the nutrient budget of the receiving basin is largely unknown. A water quality model was developed to investigate the impact of the planned Mid-Barataria Sediment Diversion on the nutrient budget of the Barataria Basin (herein referred to as ‘the Basin’). The model results indicate that the planned diversion will increase TN and TP pools by about 38% and 17%, respectively, even with TN and TP loadings that increase by >300%. Water quality model results suggest that the increase of nutrients in the basin will be mitigated by increased advection transport (i.e., decreased residence time from ~170 days to ~40 days, leading to greater flushing) and increased removal via assimilation, denitrification, and settling within the Basin. Advection transport resulted in higher TN removal in the Basin than other processes, such as uptake or denitrification. Approximately 25% of the additional TN loading and 30% of the additional TP loading were processed within the Basin through the assimilation of phytoplankton and wetland vegetation, denitrification, and burial in the sediment/soils. These nutrient budgets help to better understand how the planned large-scale sediment diversion project may change the future ecological conditions within the estuaries of coastal Louisiana and near-shore northern Gulf of Mexico.

Louisiana↗
USGS2018

Size, growth, and density data for shallow-water sea urchins from Mexico to the Aleutian Islands, Alaska, 1956–2016

Size, growth, and density have been studied for North American Pacific coast sea urchins Strongylocentrotus purpuratus , S. droebachiensis, S. polyacanthus , Mesocentrotus (Strongylocentrotus) franciscanus , Lytechinus pictus , Centrostephanus coronatus , and Arbacia stellata by various workers at diverse sites and for varying lengths of time from 1956 to present. Numerous peer-reviewed publications have used some of these data but some data have appeared only in graduate theses or the gray literature. There also are data that have never appeared outside original data sheets. Motivation for studies has included fisheries management and environmental monitoring of sewer and power plant outfalls as well as changes associated with disease epidemics. Studies also have focused on kelp restoration, community effects of sea otters, basic sea urchin biology, and monitoring. The data sets presented here are a historical record of size, density, and growth for a common group of marine invertebrates in intertidal and nearshore environments that can be used to test hypotheses concerning future changes associated with fisheries practices, shifts of predator distributions, climate and ecosystem changes, and ocean acidification along the Pacific Coast of North America and islands of the north Pacific.

Pacific Coast↗
USGS2010

Hierarchical spatial models for predicting pygmy rabbit distribution and relative abundance

Conservationists routinely use species distribution models to plan conservation, restoration and development actions, while ecologists use them to infer process from pattern. These models tend to work well for common or easily observable species, but are of limited utility for rare and cryptic species. This may be because honest accounting of known observation bias and spatial autocorrelation are rarely included, thereby limiting statistical inference of resulting distribution maps. We specified and implemented a spatially explicit Bayesian hierarchical model for a cryptic mammal species (pygmy rabbit Brachylagus idahoensis). Our approach used two levels of indirect sign that are naturally hierarchical (burrows and faecal pellets) to build a model that allows for inference on regression coefficients as well as spatially explicit model parameters. We also produced maps of rabbit distribution (occupied burrows) and relative abundance (number of burrows expected to be occupied by pygmy rabbits). The model demonstrated statistically rigorous spatial prediction by including spatial autocorrelation and measurement uncertainty. We demonstrated flexibility of our modelling framework by depicting probabilistic distribution predictions using different assumptions of pygmy rabbit habitat requirements. Spatial representations of the variance of posterior predictive distributions were obtained to evaluate heterogeneity in model fit across the spatial domain. Leave-one-out cross-validation was conducted to evaluate the overall model fit. Synthesis and applications. Our method draws on the strengths of previous work, thereby bridging and extending two active areas of ecological research: species distribution models and multi-state occupancy modelling. Our framework can be extended to encompass both larger extents and other species for which direct estimation of abundance is difficult. ?? 2010 The Authors. Journal compilation ?? 2010 British Ecological Society.

Journal of Applied Ecology↗
USGS2021

Optimization of salt marsh management at the Rachel Carson National Wildlife Refuge, Maine, through use of structured decision making

Structured decision making is a systematic, transparent process for improving the quality of complex decisions by identifying measurable management objectives and feasible management actions; predicting the potential consequences of management actions relative to the stated objectives; and selecting a course of action that maximizes the total benefit achieved and balances tradeoffs among objectives. The U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, applied an existing, regional framework for structured decision making to develop an example of a prototype tool for optimizing tidal marsh management decisions for selected marsh management units at the Rachel Carson National Wildlife Refuge in Maine. The goal was to create a prototype that could be available for future implementation. Refuge biologists, refuge managers, and research scientists identified multiple potential management actions to improve the ecological integrity of seven marsh management units within the refuge and estimated the outcomes of each action in terms of regional performance metrics associated with each management objective. Value functions previously developed at the regional level were used to transform metric scores to a common utility scale, and utilities were summed to produce a single score representing the total management benefit that could be accrued from each potential management action. Constrained optimization was used to identify the set of management actions, one per marsh management unit, that could maximize total management benefits at different cost constraints at the refuge scale. Management costs were estimated using limited available information, and estimated costs of individual management actions reflected relative differences among actions rather than actual expected expenditures. Results from this prototype showed how, for the objectives, actions, and estimated outcomes used for this example, total management benefits may increase consistently up to a certain estimated cost, and may continue to increase, at a lower rate, with further expenditures. Potential management actions in optimal portfolios at moderate total estimated costs included breaching or removing dikes, roads, or embankments; planting Spartina alterniflora (smooth cordgrass); and digging runnels, or shallow creeks, on the marsh platform to improve surface-water drainage. Potential management actions in optimal portfolios at high estimated costs (for example, up to $550,000) included breaching embankments to restore tidal exchange followed by planting salt marsh vegetation. The potential management benefits were derived from predicted increases in the numbers of tidal marsh obligate birds and spiders (as an indicator of trophic health), and expected improvement in the capacity of marsh elevation to keep pace with sea-level rise and reduced duration of marsh-surface inundation. The prototype presented here does not resolve current management decisions; rather, it provides a framework for decision making at the Rachel Carson National Wildlife Refuge that can be updated for implementation as new data and information become available. Insights from this process may also be useful to inform future habitat management planning at the refuges.

Maine↗