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USGS2022

Seed menus: An integrated decision-support framework for native plant restoration in the Mojave Desert

The combination of ecosystem stressors, rapid climate change, and increasing landscape-scale development has necessitated active restoration across large tracts of disturbed habitats in the arid southwestern United States. In this context, programmatic directives such as the National Seed Strategy for Rehabilitation and Restoration have increasingly emphasized improved restoration practices that promote resilient, diverse plant communities and enhance native seed reserves. While decision-support tools have been implemented to support genetic diversity by guiding seed transfer decisions based on patterns in local adaptation, less emphasis has been placed on identifying priority seed mixes composed of native species assemblages. Well-designed seed mixes can provide foundational ecosystem services including resilience to disturbance, resistance to invasive species, plant canopy structure to facilitate natural seedling recruitment, and habitat to support wildlife and pollinator communities. Drawing from a newly developed dataset of species distribution models for priority native plant taxa in the Mojave Desert, we created a novel decision support tool by pairing spatial predictions of species habitat with a database of key species traits including life history, flowering characteristics, pollinator relationships, and propagation methods. This publicly available web application, Mojave Seed Menus, helps restoration practitioners generate customized seed mixes for native plant restoration in the Mojave Desert while emphasizing key species traits. Our application forms an essential part of an integrated Mojave Desert restoration program designed to help practitioners identify species to include in local seed mixes and nursery stock development while accounting for local adaptation by identifying appropriate seed sources within key restoration species.

Arizona, California, Nevada, Utah↗

USGS2023

Migrating ducks and submersed aquatic vegetation respond positively after invasive common carp (Cyprinus carpio) exclusion from a freshwater coastal marsh

Invasive carp can negatively affect waterbirds through habitat degradation, including removal of submersed aquatic vegetation (SAV). At a freshwater coastal marsh of great ecological and cultural significance, we excluded invasive common carp ( Cyprinus carpio ) with the goal of restoring the marsh to historical conditions to support fall-migrating waterfowl. We used a multi-pronged approach to assess the response of ducks and SAV to carp exclusion by leveraging historical duck and SAV surveys and collecting new data for six years post-exclusion on density and distribution of ducks within the marsh, SAV response, and refueling performance (as indexed by plasma-lipid metabolites) by two species of diving ducks. We found that fall-migrating duck numbers and total SAV extent rebounded to historical levels (1970s). There was a 339% increase in diving duck density and a nearly 400% increase in dabbling duck density between the pre- (i.e., 2000s) and post-exclusion periods. Diving ducks were more likely to be observed associated with SAV within the marsh, whereas dabbling ducks responded to emergent vegetation extent and water levels. Refueling performance was stable post-exclusion, despite increased numbers of ducks using the marsh, indicating that marsh habitat quality was sufficient. Some aspects of the marsh recovery remain in question, including possible shifts in SAV community composition. Overall, the carp exclusion has successfully improved the quality of habitat for migrating ducks.

Manitoba↗

USGS2023

Factors influencing egg thiamine concentrations of Lake Ontario lake trout: 2019–2020

In the Great Lakes region, thiamine deficiency is considered a recruitment bottleneck for lake trout Salvelinus namaycush and has been correlated with the consumption of non-native alewife Alosa pseudoharengus . While alewife, the most abundant forage fish in Lake Ontario, are the predominant prey for lake trout, they also consume benthic prey such as round goby Neogobius melanostomus . Because variation in the proportion of alewife in lake trout diets is linked to variation in egg thiamine concentrations, understanding how factors such as region of capture and hatchery-strain of lake trout influence diet, are key to understanding the patterns of variation in egg thiamine concentrations observed in this species. With recent increases in natural recruitment of lake trout being observed in the western region of the lake, understanding if egg thiamine is a potential driver is crucial to the rehabilitation of lake trout. In this study, we evaluated egg thiamine concentrations in lake trout during 2019–2020. We found no significant difference in egg thiamine concentrations among regions. However, a stocked Lake Superior deepwater morphotype (Superior Klondike Wild – SKW) showed significantly higher egg thiamine concentrations compared to the lean morphotype including Seneca (SEN) and Lake Champlain Domestic (LCD) strains. An analysis of fatty acid signatures of each hatchery-strain suggested that the SKW strain consumed a higher proportion of round goby than lean strains. Overall, these results suggest that morphotypic differences in the feeding ecology of lake trout can result in biochemical changes which may influence the effectiveness of restoration efforts.

Lake Ontario↗

USGS1995

Effects of agricultural, industrial, and municipal pollutants on wetlands and wildlife and wildlife health

Wetlands accumulate pollutants from adjacent areas through intentional discharge of sewage or industrial wastes, runoff of agricultural fertilizers and pesticides, and discharge from municipal storm drains. Coastal wetlands receive more pollutants indirectly as the endpoint for upland drainage systems and directly through petroleum spills and insect abatement. Wetlands that serve as evaporation basins during seasonally high water, especially in more arid climates, concentrate natural compounds and as well as pollutants. The ability of wetlands to be effective filtration systems for wastewater nutrients through microbial transformations, uptake by plants, and deposition of particulate matter, and the shortage of water in arid climates has resulted in revision of wetland regulations. Wetlands can now be developed for wastewater treatment and natural wetlands can be restored or converted to wastewater treatment systems. The effect of these accumulation pollutants on wetland ecology and wildlife health needs to be recognized.

Conference Paper↗

USGS2013

Sedimentology of new fluvial deposits on the Elwha River, Washington, USA, formed during large-scale dam removal

Removal of two dams 32 m and 64 m high on the Elwha River, Washington, USA, provided the first opportunity to examine river response to a dam removal and controlled sediment influx on such a large scale. Although many recent river-restoration efforts have included dam removal, large dam removals have been rare enough that their physical and ecological effects remain poorly understood. New sedimentary deposits that formed during this multi-stage dam removal result from a unique, artificially created imbalance between fluvial sediment supply and transport capacity. River flows during dam removal were essentially natural and included no large floods in the first two years, while draining of the two reservoirs greatly increased the sediment supply available for fluvial transport. The resulting sedimentary deposits exhibited substantial spatial heterogeneity in thickness, stratal-formation patterns, grain size and organic content. Initial mud deposition in the first year of dam removal filled pore spaces in the pre-dam-removal cobble bed, potentially causing ecological disturbance but not aggrading the bed substantially at first. During the second winter of dam removal, thicker and in some cases coarser deposits replaced the early mud deposits. By 18 months into dam removal, channel-margin and floodplain deposits were commonly >0.5 m thick and, contrary to pre-dam-removal predictions that silt and clay would bypass the river system, included average mud content around 20%. Large wood and lenses of smaller organic particles were common in the new deposits, presumably contributing additional carbon and nutrients to the ecosystem downstream of the dam sites. Understanding initial sedimentary response to the Elwha River dam removals will inform subsequent analyses of longer-term sedimentary, geomorphic and ecosystem changes in this fluvial and coastal system, and will provide important lessons for other river-restoration efforts where large dam removal is planned or proposed.

Washington↗

USGS2014

Opposing resonses to ecological gradients structure amphibian and reptile communities across a temperate grassland-savanna-forest landscape

Temperate savannas are threatened across the globe. If we prioritize savanna restoration, we should ask how savanna animal communities differ from communities in related open habitats and forests. We documented distribution of amphibian and reptile species across an open-savanna–forest gradient in the Midwest U.S. to determine how fire history and habitat structure affected herpetofaunal community composition. The transition from open habitats to forests was a transition from higher reptile abundance to higher amphibian abundance and the intermediate savanna landscape supported the most species overall. These differences warn against assuming that amphibian and reptile communities will have similar ecological responses to habitat structure. Richness and abundance also often responded in opposite directions to some habitat characteristics, such as cover of bare ground or litter. Herpetofaunal community species composition changed along a fire gradient from infrequent and recent fires to frequent but less recent fires. Nearby (200-m) wetland cover was relatively unimportant in predicting overall herpetofaunal community composition while fire history and fire-related canopy and ground cover were more important predictors of composition, diversity, and abundance. Increased developed cover was negatively related to richness and abundance. This indicates the importance of fire history and fire related landscape characteristics, and the negative effects of development, in shaping the upland herpetofaunal community along the native grassland–forest continuum.

Indiana↗

USGS2015

Managing the Mississippi River floodplain: Achieving ecological benefits requires more than hydrological connection to the river: Chapter

Floodplains are vital to the structure and function of river-floodplain ecosystems. Among the many ecological services provided by floodplains are nutrient cycling and seasonal habitats for fish, including spawning, nursery, foraging and wintering habitats. Connections between the river channel and floodplain habitats are essential to realize these ecological services, but spatial and temporal aspects of the connection and contemporary geomorphology must also be considered in restoration efforts. This chapter synthesizes available information to compare floodplain function and needed management strategies in two extensive reaches (upper impounded and lower free-flowing) of the Mississippi River, USA. The upper impounded reach is the 523-km reach from about Minneapolis, Minnesota to Clinton, Iowa. This reach has been impounded and channelized for navigation. Mean annual water-level fluctuation ranges from 1 to 2 m in the navigation pools in this reach. Floodplain environmental conditions that affect nitrogen cycling and fish production vary seasonally and longitudinally within and among navigation pools. Significant issues affecting ecological services include sedimentation, constrained water level fluctuations, island erosion and seasonal hypoxia. The lower free-flowing reach, the 1570-km reach from the confluence of the Ohio and Mississippi rivers to the Gulf of Mexico, has no dams and average annual fluctuations of 7 m throughout most of the reach. Despite the substantial flood pulse, floodplain inundation is often brief and may not occur annually. Significant issues affecting floodplain ecological function are the short duration and thermal asynchrony of the flood pulse, sedimentation and loss of connection between the river channel and permanent/semi-permanent floodplain water bodies due to channel incision. Needs and strategies for floodplain enhancement to increase ecological services, particularly nitrogen cycling and fish production, differ along the longitudinal gradient of the Mississippi River and provide informative contrasts to guide floodplain management. Prediction of the effects of climate change on this system will be complicated by the magnitude of the watershed that encompasses 41 % of the continental USA and multiple climatic regions.

Mississippi River floodplain↗

USGS2021

Oyster model inventory: Identifying critical data and modeling approaches to support restoration of oyster reefs in coastal U.S. Gulf of Mexico waters

Executive Summary Along the coast of the U.S. Gulf of Mexico, the eastern oyster ( Crassostrea virginica ) plays important ecological and economic roles. Commercial landings from this region account for more than 50 percent of all U.S. landings; these oyster reefs also provide varied ecosystem services, including nursery habitat for many fish and macroinvertebrate species, shoreline protection, and water-quality maintenance. Declining trends in both total oyster production and functional reef area across this region have spurred investment in restoration of oyster resources, with specific calls for restoration projects to develop a network of reefs and identify broodstock and sanctuary reef restoration sites. Decision making related to restoration and establishment of a network of oyster reefs in the Gulf of Mexico requires information on both the environment and the effects of the environment on the oyster life cycle (including larval movement, survival, oyster recruitment, reproduction, growth, and mortality). Here, we examined the current state of data and model development in this region with the goal of providing an overview of oyster modeling approaches and an inventory of available data and existing oyster models. This report is meant to provide an overview to managers for understanding existing efforts and identify a path forward to most efficiently inform oyster resource management and restoration planning in moving from a single reef management approach to a reef network management approach. Numerous models related to some aspect of the oyster life cycle have been built, calibrated, and validated for various Gulf of Mexico estuaries over the last few decades (over 30 models identified). These models, which could inform site restoration, can be classified into four approaches: (1) oyster Habitat Suitability Index (HSI) models; (2) larval transport models; (3) on-reef oyster models that may include oyster growth, mortality and reproduction, and substrate persistence; and (4) coupled larval transport on-reef metapopulation models that simulate the entire oyster life cycle. The data requirements, model complexity and assumptions, and transferability vary by approach. Specifically, some approaches may offer greater accessibility, flexibility, and transferability spatially or temporally, with minimal data input, but only provide broad information to support site selection. In contrast, other approaches may require significant site-specific data for their construction and validation but may provide more accurate and location-specific data to support site selection for broodstock reefs. Regardless of modeling approach used, data on environmental drivers, such as salinity, water temperature, or water flow impacting oyster metabolism and movement, are required at appropriate spatial and temporal scales. While numerous data collection platforms, environmental models, and research products exist within Gulf of Mexico estuaries to provide important environmental data to use as drivers in the oyster models, significant variability in temporal and spatial coverage of the data, and variation in the availability of future condition models, exists across estuaries. This variation influences the spatial and temporal scales at which oyster models may be developed and impacts the calibration and validation of the oyster models within a given estuary, affecting its potential ability to address specific management or restoration questions. While multiple modeling approaches exist for informing site selection of broodstock or sanctuary oyster reefs, the development, calibration, and validation of a single modeling platform presents the most efficient, transferable, and useful tool for managers across the Gulf of Mexico. The development of a single modeling platform would involve using standardized input variables, governing equations, and assumptions for the modeled oyster processes and outputs, and for standardized calibration and validation procedures that could be applied within each estuary. The differences among estuary applications would require substituting only estuary-specific environmental data, and calibrating and validating the modeling approach with local oyster data. Two modeling approaches likely to be useful include (1) development of a general geospatial HSI modeling framework that could be applied consistently across estuaries and (2) a mechanistic coupled larval transport on-reef metapopulation model requiring only estuarine specific calibration and hydrodynamic models. Both approaches benefit from existing work across multiple Gulf of Mexico estuaries and could provide valuable support for oyster restoration, but may differ in their ability to address specific questions related to oyster restoration. HSI models specifically guide restoration practitioners in determining suitable habitat based on available data. The HSI approach, while currently more widely used and accessible, requires more development of larval suitability and larval input and output components in order to inform reef connectivity. A metapopulation approach considering the full oyster life cycle that simulates both on-reef oyster growth, mortality, reproduction, substrate persistence, and larval transport (ideally with larval growth and mortality) would provide the greatest detail and level of understanding but requires significant up-front investment. The larval oyster model and on-reef oyster model are usually developed independently for systems, although the two approaches can be coupled to represent the entire oyster life cycle in order to characterize and assess a reef metapopulation. This approach may be less accessible and much more data-intensive, however, and it requires some expertise to run and apply to inform oyster resource management. Ultimately, the development of single modeling platforms for each of these approaches would provide flexible tools applicable across all Gulf of Mexico oyster supporting estuaries. By using a single platform for model development, testing, calibrating and validating, and evaluation of modeled future scenarios, oyster restoration scientists and managers would not only be able to examine different scenario outcomes within a single estuary, but could also have comparable modeled results to evaluate potential outcomes, across estuaries and regions, that are not confounded by varying modeled data inputs, governing equations, assumptions, or user judgement.

Alabama, Florida, Louisiana, Mississippi, Texas↗

USGS2020

The biggest bang for the buck: Cost‐effective vegetation treatment outcomes across drylands of the western United States

Restoration and rehabilitation are globally implemented to improve ecosystem condition but often without tracking treatment expenditures relative to ecological outcomes. We evaluated the cost‐effectiveness of widely conducted woody plant and herbaceous invasive plant removals and seeding treatments in drylands of the western United States from 2004 to 2018 to determine how land managers can optimize efforts. Woody plant cover decreased at a similar rate per dollar spent regardless of vegetation removal type, and the dominant invasive species was reduced by herbicide application. Relatively inexpensive herbicide application also had a large positive effect on seeded perennial grass cover that was enhanced by additional cost; while expensive woody mastication treatments had little effect regardless of additional cost. High seed cost was driven by including a large proportion of native species in seed mixes, and combined with high seeding cost, promoted a short‐term (2–3 yr) gain in perennial forb cover and species richness. In contrast, seeding and seed mix cost had no bearing on seeded perennial grass cover, in part, because relatively cheap nonnative seeded species rapidly increased in cover. Our results suggest the differential benefits of commonly implemented treatments aimed at reducing wildfire risk, improving wildlife habitat and forage, and reducing erosion. Given the growing need and cost of restoration and rehabilitation, we raise the importance of specifying treatment budgets and objectives, coupled with effectiveness monitoring, to improve future outcomes.

Utah↗

USGS2015

Development of an assessment tool for agricultural best management practice implementation in the Great Lakes Restoration Initiative priority watersheds—Upper East River, tributary to Green Bay, Wisconsin

Introduction The Great Lakes face a number of serious challenges that cause damage to water quality, habitat, ecology, and coastal health. Excess nutrients from point and nonpoint sources have a history of causing harmful algal blooms (HABs); since the late 1990s, a resurgence of HABs have forced beach closures and resulted in water quality impairments across the Great Lakes. Studies increasingly point to phosphorus (P) runoff from agricultural lands as the cause of these HABs. In 2010, the Great Lakes Restoration Initiative (GLRI) was launched to revitalize the Great Lakes. The GLRI aims to address the challenges facing the Great Lakes and provide a framework for restoration and protection. As part of this effort, the Priority Watersheds Work Group (PWWG), cochaired by the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Agriculture-Natural Resources Conservation Service (USDA–NRCS), is targeting Priority Watersheds (PWs) to reduce the amount of P reaching the Great Lakes. Within the PWs, USDA–NRCS identifies small-scale subbasins with high concentrations of agriculture for coordinated nutrient reduction efforts and enhanced monitoring and modeling. The USDA–NRCS supplies financial and/or technical assistance to producers to install or implement best management practices (BMPs) to lessen the negative effects of agriculture to water quality; additional funding is provided by the GLRI through USDA–NRCS to saturate the small-scale subbasins with BMPs. The watershed modeling component, introduced in this fact sheet, assesses the effectiveness of USDA–NRCS funded BMPs, and nutrient reductions because of GLRI or other funding programs are differentiated. Modeling scenarios consider BMPs that have already been applied and those planned to be implemented across the small-scale subbasins.

Wisconsin↗

USGS2023

Bedform distributions and dynamics in a large, channelized river: Implications for benthic ecological processes

Sand bedforms are fundamental habitat elements for benthic fish in large, sand-bedded rivers and are hypothesized to provide flow refugia, food transport, and ecological disturbance. We explored bedform distributions and dynamics in the Lower Missouri River, Missouri, with the objective of understanding the implications of these features for benthic fish habitat, particularly for the endangered pallid sturgeon (Scaphirhynchus albus) and shovelnose sturgeon (Scaphirhynchus platorynchus) during their early life stages. We mapped bathymetry in a 3-kilometer-long reach of the highly engineered Lower Missouri River 22 times over a three-year period from 2019-2021 using a multibeam echosounder. Surveys included precise water surface and bed elevations over discharges ranging from 1,360-8,550 cubic meters per second. This included weekly surveys during a large flood event with a peak of 9,290 cubic meters per second in the spring and summer of 2019. Velocity was mapped with an acoustic Doppler current profiler during 11 of the 22 multibeam surveys. The dataset illustrates how bedforms are distributed in a typical Missouri River reach and how they evolve with changes in discharge. We measured a variety of bedform characteristics, including height, length, lee-slope angle, and crest orientation, and examined their relationship to larval sturgeon catch in the reach in 2020 and 2021. Bedform shapes are controlled by depositional environment and discharge and range in size from less than a meter in wavelength and amplitude to greater than 4 meters high and 75 meters long and generally have low angle lee-slopes. Small dunes were located in lower velocity regions on the inside of a bend and behind wing-dikes, as well as superimposed on larger dunes. Larger dunes were generally located in the channel thalweg and were associated with higher flow velocities. However, bedform size did not necessarily scale with discharge over the course of the 2019 flood, possibly due to sediment supply limitations and hysteresis effects. Changes in bedform size over the course of the flood event were most pronounced in the thalweg; less change in bedform size occurred behind wing dikes on the inside of channel bends, indicating some degree of habitat stability. Despite rarely getting caught in the thalweg, larval sturgeon drift in the thalweg until they are intercepted into off-channel habitats in wing dike fields, where they are caught in much higher numbers. Bedform orientations were affected by flow expansion around wing dikes, indicative of the role of wing dikes in influencing exchange of material between the thalweg and channel margins. Increased understanding of bedform distributions and dynamics will inform future sampling and habitat restoration designs for larval pallid sturgeon and contribute to increased understanding of their influence on benthic ecological processes.

Conference Paper↗

USGS2012

Timing and synchrony of births in bighorn sheep: implications for reintroduction and conservation

Context: Timing (mean birthdate) and synchrony (variance around that date) of births can influence survival of young and growth in ungulate populations. Some restored populations of ungulates may not adjust these life-history characteristics to environments of release sites until several years after release, which may influence success of reintroductions. Aims: We quantified timing and synchrony of births from 2005 to 2007 in four populations of reintroduced bighorn sheep ( Ovis canadensis ) occupying two ecoregions (Central Basin and Range and Wasatch and Uinta Mountains) in Utah, USA, to investigate whether bighorns would adjust these life-history characteristics to environmental conditions of the two ecoregions. We also compared timing and synchrony of births for bighorns in their source herd (Antelope Island) with bighorns in an ecologically similar release site (Stansbury Mountains) during 2006 and 2007. Methods: We relocated female bighorns to record birthdates of young, and observed groups of collared bighorns to quantify use of elevation by those ungulates. We also calculated the initiation, rate and timing of peak green-up by ecoregion, using the normalised difference vegetation index. Key results: We quantified 274 birthdates, and although only separated by 57 km, bighorn populations occupying the Central Basin and Range Mountains gave birth an average of 29 days earlier than did those on the Wasatch and Uinta Mountains, which corresponded with the initiation of vegetation green-up. Additionally, bighorn sheep on the Stansbury Mountains (ecologically similar release site) gave birth at similar times as did bighorns on Antelope Island (source area). Conclusions: Populations of bighorn sheep that were reintroduced into adjacent ecoregions adjusted timing of births to environments and green-up of vegetation in restoration areas. Timing and synchrony of births for reintroduced bighorn sheep in an ecologically similar release site were the same as those of their source area. Implications: Consideration should be given to the adjustment of timing and synchrony of births when reintroducing bighorns, especially when animals are released into different ecoregions. Also, biologists should select release sites that are ecologically similar to source areas, thereby reducing potential negative effects of animals adjusting timing and synchrony of births to environmental conditions of restoration areas.

Wildlife Research↗

USGS2014

Integrated conceptual ecological model and habitat indices for the southwest Florida coastal wetlands

The coastal wetlands of southwest Florida that extend from Charlotte Harbor south to Cape Sable, contain more than 60,000 ha of mangroves and 22,177 ha of salt marsh. These coastal wetlands form a transition zone between the freshwater and marine environments of the South Florida Coastal Marine Ecosystem (SFCME). The coastal wetlands provide diverse ecosystem services that are valued by society and thus are important to the economy of the state. Species from throughout the region spend part of their life cycle in the coastal wetlands, including many marine and coastal-dependent species, making this zone critical to the ecosystem health of the Everglades and the SFCME. However, the coastal wetlands are increasingly vulnerable due to rising sea level, changes in storm intensity and frequency, land use, and water management practices. They are at the boundary of the region covered by the Comprehensive Everglades Restoration Plan (CERP), and thus are impacted by both CERP and marine resource management decisions. An integrated conceptual ecological model (ICEM) for the southwest coastal wetlands of Florida was developed that illustrates the linkages between drivers, pressures, ecological process, and ecosystem services. Five ecological indicators are presented: (1) mangrove community structure and spatial extent; (2) waterbirds; (3) prey-base fish and macroinvertebrates; (4) crocodilians; and (5) periphyton. Most of these indicators are already used in other areas of south Florida and the SFCME, and therefore will allow metrics from the coastal wetlands to be used in system-wide assessments that incorporate the entire Greater Everglades Ecosystem.

Ecological Indicators↗

USGS2023

Fuel treatments in shrublands experiencing pinyon and juniper expansion result in trade-offs between desired vegetation and increased fire behavior

Background Native pinyon ( Pinus spp.) and juniper ( Juniperus spp.) trees are expanding into shrubland communities across the Western United States. These trees often outcompete with native sagebrush ( Artemisia spp.) associated species, resulting in increased canopy fuels and reduced surface fuels. Woodland expansion often results in longer fire return intervals with potential for high severity crown fire. Fuel treatments are commonly used to prevent continued tree infilling and growth and reduce fire risk, increase ecological resilience, improve forage quality and quantity, and/or improve wildlife habitat. Treatments may present a trade-off; they restore shrub and herbaceous cover and decrease risk of canopy fire but may increase surface fuel load and surface fire potential. We measured the accumulation of surface and canopy fuels over 10 years from ten sites across the Intermountain West in the Sagebrush Steppe Treatment Evaluation Project woodland network ( www.SageSTEP.org ), which received prescribed fire or mechanical (cut and drop) tree reduction treatments. We used the field data and the Fuel Characteristic Classification System (FCCS) in the Fuel and Fire Tools (FFT) application to estimate surface and canopy fire behavior in treated and control plots in tree expansion phases I, II, and III. Results Increased herbaceous surface fuel following prescribed fire treatments increased the modeled rate of surface fire spread (ROS) 21-fold and nearly tripled flame length (FL) by year ten post-treatment across all expansion phases. In mechanical treatments, modeled ROS increased 15-fold, FL increased 3.8-fold, and reaction intensity roughly doubled in year ten post-treatment compared to pretreatment and untreated controls. Treatment effects were most pronounced at 97th percentile windspeeds, with modeled ROS up to 82 m min −1 in mechanical and 106 m min −1 in prescribed fire treatments by 10 years post-treatment compared to 5 m min −1 in untreated controls. Crown fire transmissivity risk was eliminated by both fuel treatments. Conclusions While prescribed fire and mechanical treatments in shrublands experiencing tree expansion restored understory vegetation and prevented continued juniper and pinyon infilling and growth, these fuel treatments also increased modeled surface fire behavior. Thus, management tradeoffs occur between desired future vegetation and wildfire risk after fuel treatments.

California, Nevada, Oregon, Utah↗

USGS2006

Understanding the genetic effects of recent habitat fragmentation in the context of evolutionary history: Phylogeography and landscape genetics of a southern California endemic Jerusalem cricket (Orthoptera: Stenopelmatidae: Stenopelmatus)

Habitat loss and fragmentation due to urbanization are the most pervasive threats to biodiversity in southern California. Loss of habitat and fragmentation can lower migration rates and genetic connectivity among remaining populations of native species, reducing genetic variability and increasing extinction risk. However, it may be difficult to separate the effects of recent anthropogenic fragmentation from the genetic signature of prehistoric fragmentation due to previous natural geological and climatic changes. To address these challenges, we examined the phylogenetic and population genetic structure of a flightless insect endemic to cismontane southern California, Stenopelmatus 'mahogani' (Orthoptera: Stenopelmatidae). Analyses of mitochondrial DNA sequence data suggest that diversification across southern California began during the Pleistocene, with most haplotypes currently restricted to a single population. Patterns of genetic divergence correlate with contemporary urbanization, even after correcting for (geographical information system) GIS-based reconstructions of fragmentation during the Pleistocene. Theoretical simulations confirm that contemporary patterns of genetic structure could be produced by recent urban fragmentation using biologically reasonable assumptions about model parameters. Diversity within populations was positively correlated with current fragment size, but not prehistoric fragment size, suggesting that the effects of increased drift following anthropogenic fragmentation are already being seen. Loss of genetic connectivity and diversity can hinder a population's ability to adapt to ecological perturbations commonly associated with urbanization, such as habitat degradation, climatic changes and introduced species. Consequently, our results underscore the importance of preserving and restoring landscape connectivity for long-term persistence of low vagility native species. Journal compilation ?? 2006 Blackwell Publishing Ltd.

Molecular Ecology↗

USGS2020

Review of trap-and-haul for managing Pacific salmonids (Oncorhynchus spp.) in impounded river systems

High-head dams are migration barriers for Pacific salmon Oncorhynchus spp. in many river systems and recovery measures for impacted stocks are limited. Trap-and-haul has been widely used in attempts to facilitate recovery but information from existing programs has not been synthesized to inform improvements to aid recovery of salmonids in systems with high-head dams. We reviewed 17 trap-and-haul programs regarding Pacific salmon to: (1) summarize information about facility design, operation and biological effects; (2) identify critical knowledge gaps; and (3) evaluate trap-and-haul as a current and future management tool. Existing programs are operated to address a range of management goals including restoring access to historical habitats, temporarily reducing exposure to dangerous in-river conditions, and reintroducing ecological processes upstream from dams. Information gathered from decades of operation on facility design criteria and fish handling protocols, and robust literature on fish collection and passage are available. While many aspects of trap-and-haul have been evaluated, effects on population productivity and sustainability remain poorly understood. Long-term and systematic studies of trap-and-haul outcomes are rare, and assessments can be confounded by concurrent management actions and broad ecological and climatic effects. Existing data suggest that performance and effectiveness vary among programs and over various time scales within programs. Although critical information gaps exist, trap-and-haul is an important management and conservation tool for providing Pacific salmonids access to historical habitats. Successful application of trap-and-haul programs requires long-term commitment and an adaptive management approach by dam owners and stakeholders, and careful planning of new programs.

California, Idaho, Oregon, Washington↗

USGS2021

Dam removal and river restoration

The removal of dams from rivers has become a common and widespread practice in the United States and Europe. Although often initiated by factors like economics and safety, ecosystem restoration is often a desired benefit and outcome of dam removal. We describe the physical and ecological effects that the placement and removal of dams have on rivers. We then focus on the drivers of dam removal, present considerations for undertaking a dam removal project, and discuss case-studies and recent syntheses describing the ecological outcomes of dam removal.

Book chapter↗

USGS2011

The role of the Everglades Mangrove Ecotone Region (EMER) in regulating nutrient cycling and wetland productivity in South Florida

The authors summarize the main findings of the Florida Coastal Everglades Long-Term Ecological Research (FCE-LTER) program in the EMER, within the context of the Comprehensive Everglades Restoration Plan (CERP), to understand how regional processes, mediated by water flow, control population and ecosystem dynamics across the EMER landscape. Tree canopies with maximum height <3 m cover 49% of the EMER, particularly in the SE region. These scrub/dwarf mangroves are the result of a combination of low soil phosphorus (P < 59 μg P g dw −1 ) in the calcareous marl substrate and long hydroperiod. Phosphorus limits the EMER and its freshwater watersheds due to the lack of terrigenous sediment input and the phosphorus-limited nature of the freshwater Everglades. Reduced freshwater delivery over the past 50 years, combined with Everglades compartmentalization and a 10 cm rise in coastal sea level, has led to the landward transgression (∼1.5 km in 54 years) of the mangrove ecotone. Seasonal variation in freshwater input strongly controls the temporal variation of nitrogen and P exports (99%) from the Everglades to Florida Bay. Rapid changes in nutrient availability and vegetation distribution during the last 50 years show that future ecosystem restoration actions and land use decisions can exert a major influence, similar to sea level rise over the short term, on nutrient cycling and wetland productivity in the EMER.

Florida↗