SEARCH · Geology Reports

Results for “Nature Conservation”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

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

USGS2020

Spatial conservation planning under uncertainty using modern portfolio theory and nash bargaining solution

In recent years, researchers from interdisciplinary teams involving ecologists, economists and operations re- searchers collaborated to provide decision support tools to address the challenges of preserving biodiversity by optimizing the design of reserves. The goal of this paper is to further advance this area of research and provide new solutions to solve complex Spatial Conservation Planning (SCP) problems under uncertainty that consider risk preferences of decision makers. Our approach employs modern portfolio theory to address uncertainties in SCP problems, and involves two conflicting objectives: maximizing return and minimizing risk. We apply concepts from game theory such as the Nash bargaining solution to directly compute a desirable Pareto-optimal solution for the proposed bi-objective optimization formulation in natural resource management problems. We demonstrate with numerical examples that by directly computing a Nash bar- gaining solution, a Binary Quadratically Constrained Quadratic Program (BQCQP) can be solved. We show that our approach (implementable with commercial solvers such as CPLEX) can effectively solve the proposed BQCQP for much larger problems than previous approaches published in the ecological literature. Optimal solutions for problems with less than 400 parcels can be computed within a minute. Near optimal solutions (within at most 0.2% gap from an optimal solution) for high-dimensional problems involving up to 800 parcels can be computed within 8 hours on a standard computer. We have presented a new approach to solve SCP optimization problems while considering uncertainty and risk tolerance of decision makers. Our new approach expands considerably the applicability of such SCP optimization methods to address real conservation problems.

Ecological Modelling↗

USGS2021

Is the grass always greener? Land surface phenology reveals differences in peak and season-long vegetation productivity responses to climate and management

Vegetation phenology—the seasonal timing and duration of vegetative phases—is controlled by spatiotemporally variable contributions of climatic and environmental factors plus additional potential influence from human management. We used land surface phenology derived from the Advanced Very High Resolution Radiometer and climate data to examine variability in vegetation productivity and phenological dates from 1989 to 2014 in the U.S. Northwestern Plains, a region with notable spatial heterogeneity in climate, vegetation, and land use. We first analyzed interannual trends in six phenological measures as a baseline. We then demonstrated how including annual-resolution predictors can provide more nuanced insights into measures of phenology between plant communities and across the ecoregion. Across the study area, higher annual precipitation increased both peak and season-long productivity. In contrast, higher mean annual temperatures tended to increase peak productivity but for the majority of the study area decreased season-long productivity. Annual precipitation and temperature had strong explanatory power for productivity-related phenology measures but predicted date-based measures poorly. We found that relationships between climate and phenology varied across the region and among plant communities and that factors such as recovery from disturbance and anthropogenic management also contributed in certain regions. In sum, phenological measures did not respond ubiquitously nor covary in their responses. Nonclimatic dynamics can decouple phenology from climate; therefore, analyses including only interannual trends should not assume climate alone drives patterns. For example, models of areas exhibiting greening or browning should account for climate, anthropogenic influence, and natural disturbances. Investigating multiple aspects of phenology to describe growing-season dynamics provides a richer understanding of spatiotemporal patterns that can be used for predicting ecosystem responses to future climates and land-use change. Such understanding allows for clearer interpretation of results for conservation, wildlife, and land management.

Ecology and Evolution↗

USGS2008

Storm-generated coral fragments - A viable source of transplants for reef rehabilitation

Coral reefs throughout the world have been damaged by storms, diseases, coral predators, temperature anomalies, and human activities. During the past three decades, recovery has been limited and patchy. Although a damaged coral reef cannot be restored to its original condition, interest in reef restoration is increasing. In a pilot project in the Caribbean (US Virgin Islands), storm-produced fragments of Acropora palmata, A. cervicornis, and Porites porites were collected from donor reefs and transplanted to nearby degraded reefs. Sixty coral fragments were attached to dead-coral substrate (usually A. palmata skeletons), at similar depths from which they had been collected (1-3.5 m), using nylon cable ties. Seventy-five intact colonies were designated as controls. Study colonies were assessed at 6-month intervals for 2 years (1999-2001) and annually thereafter (through 2004). One-fourth of the 135 colonies and fragments monitored were alive at the conclusion of the 5-year study. Survival of control and transplanted A. cervicornis and P. porites was very low (median survival 2.4 and 1.8 years, respectively), with no significant differences between transplant and control colonies. Site and depth did not contribute significantly to A. palmata colony survival, but colony size and transplant/control status did. Probability of survival increased with colony size. Median survival for A. palmata was 1.3 years for transplant and 4.3 years for natural colonies when not controlled for size. A. palmata was the only viable candidate for reef rehabilitation. Storm swells were the primary cause of mortality.

Biological Conservation↗

USGS2014

A systematic approach towards the identification and protection of vulnerable marine ecosystems

The United Nations General Assembly in 2006 and 2009 adopted resolutions that call for the identification and protection of vulnerable marine ecosystems (VMEs) from significant adverse impacts of bottom fishing. While general criteria have been produced, there are no guidelines or protocols that elaborate on the process from initial identification through to the protection of VMEs. Here, based upon an expert review of existing practices, a 10-step framework is proposed: (1) Comparatively assess potential VME indicator taxa and habitats in a region; (2) determine VME thresholds; (3) consider areas already known for their ecological importance; (4) compile information on the distributions of likely VME taxa and habitats, as well as related environmental data; (5) develop predictive distribution models for VME indicator taxa and habitats; (6) compile known or likely fishing impacts; (7) produce a predicted VME naturalness distribution (areas of low cumulative impacts); (8) identify areas of higher value to user groups; (9) conduct management strategy evaluations to produce trade-off scenarios; (10) review and re-iterate, until spatial management scenarios are developed that fulfil international obligations and regional conservation and management objectives. To date, regional progress has been piecemeal and incremental. The proposed 10-step framework combines these various experiences into a systematic approach.

Marine Science↗

USGS2002

Wildlife association with human‐altered water sources in semiarid vegetation communities

Based on common use in wildlife management, we hypothesized that human‐constructed water sources influence faunal communities detectably compared to similar habitats that lack water. We examined 20 wildlife water units and 20 paired comparison sites without water from April to August 1992 in semiarid southern New Mexico to assess animal species associations. We sampled sites by using small‐mammal live traps, herpetofaunal and invertebrate pitfall arrays, and 30‐minute time‐area counts. We compared animal species richness and species concordance among water units (rain catchments, earthen tanks, and windmills) and comparison sites in three vegetation communities (mixed scrub, grassland, and pinyon‐juniper). We detected 134 animal taxa during field sampling. Animal species richness did not differ between water units and comparison sites among vegetation communities. Amphibians were found only at water units but occur far from units during seasonal wet periods. Greater numbers of individual small mammals and herpetofauna at water units versus comparison sites likely related to debris and disturbed soil present near water units. Taxa detected at water units and comparison sites were 65% concordant overall; discordant taxa were those rarely detected. Our data implied that definitive effects of artificial water sources on native wildlife species were not detectable. Providing water sources may be a strategic management tool but must be viewed critically regarding effect on distribution of native, feral, and exotic animals. Water units should be developed only when and where clear objectives have been stated, natural water sources have been quantified, commitment exists to ensure continued function, and feral and exotic animals will not benefit to the detriment of native species.

New Mexico↗

USGS2019

Geochemical data for produced waters from conventional and unconventional oil and gas wells: Results from Colorado, USA

Geochemical data for more than 120,000 oil and natural gas wells from the major sedimentary basins in the USA are listed in the USGS National Produced Waters Geochemical Database [1]. In this summary, we report and discuss the geochemical data on produced waters obtained from published literature and the Colorado Oil and Gas Conservation Commission (COGCC) from close to 4,000 new oil and gas wells in Colorado. We emphasize geochemical data of produced waters from shale and tight reservoirs that have increased dramatically in Colorado since 2011, due to deep horizontal drilling, downhole telemetry and massive multi-stage hydraulic fracturing. These operations require large volumes of fresh water, but contamination of groundwater is the major environmental concern. Also, induced seismicity caused by water injection has been reported from several areas in Colorado, including Trinidad, Raton basin, and Greely, Denver basin. Produced water salinities in Colorado obtained from unconventional oil and gas wells are relatively low, generally less than 30,000 mg/L TDS. Produced water salinities from conventional oil and gas wells overlap those from unconventional wells, but many wells have higher salinities (up to 90,000 mg/L TDS) and different chemical compositions.

Colorado↗

USGS2011

Multispecies modeling for adaptive management of horseshoe crabs and red knots in the Delaware Bay

Adaptive management requires that predictive models be explicit and transparent to improve decisions by comparing management actions, directing further research and monitoring, and facilitating learning. The rufa subspecies of red knots ( Calidris canutus rufa ), which has recently exhibited steep population declines, relies on horseshoe crab ( Limulus polyphemus ) eggs as their primary food source during stopover in Delaware Bay during spring migration. We present a model with two different parameterizations for use in the adaptive management of horseshoe crab harvests in the Delaware Bay that links red knot mass gain, annual survival, and fecundity to horseshoe crab dynamics. The models reflect prevailing hypotheses regarding ecological links between these two species. When reported crab harvest from 1998 to 2008 was applied, projections corresponded to the observed red knot population abundances depending on strengths of the demographic relationship between these species. We compared different simulated horseshoe crab harvest strategies to evaluate whether, given this model, horseshoe crab harvest management can affect red knot conservation and found that restricting harvest can benefit red knot populations. Our model is the first to explicitly and quantitatively link these two species and will be used within an adaptive management framework to manage the Delaware Bay system and learn more about the specific nature of the linkage between the two species.

Delaware, New Jersey↗

USGS1974

Studying the Earth from space

Pictures of the Earth's surface obtained from satellites are providing scientists with new tools to investigate tne Earth and its environment. A growing population and an everexpanding technology place demands on our natural resources. However, man can no longer treat his resources strictly according to immediate economic dictates; a balance must be struck between the short-term demands of technological and industrial development and the long-term effects on the environment. Intelligent development, management, and conservation of resources are goals that represent an unprecedented challenge in the acquisition and use of information.

General Interest Publication↗

USGS2002

Human impact on the planet: an earth system science perspective and ethical considerations

The modern Earth Narrative, the scientific story of the 4.5 billion-year natural and human history of the Earth, has emerged from the solid foundation of two factual concepts: Deep (or Geologic) Time and Biological Evolution. spread acceptance of the Earth Narrative is critically important as we begin the third millennium, because it provides a clear understanding of the growing impact of human population growth and associated activities on the Earth System, especially the negative impact on Earth?s biosphere. It is important for humans to realize that we are but one of 4,500 species of mammals that exist on Earth and that we are but one species in the estimated 30 to 100 million species that form the complex biosphere. We also need to recognize that all species exist within the physical limits imposed by the geosphere. We are totally dependent on the biosphere for food, oxygen, and other necessities of life. mans are one of the latest results of biological evolution operating over a long period of Geologic Time. We find ourselves on Earth, after 4.5 billion years of Earth history by chance, not by design. Humans have become so successful at modifying their environment that many of the natural limitations on the expansion of populations of our fellow animals have been overcome by technological and cultural innovations. According to Peter Raven, ?Humans, at a current population of 6 billion [expected to nearly double by 2050], are consuming or wasting about 50 percent of the total net biological productivity on land and 50 percent of the available supply of freshwater. The overwhelming and expanding human presence leaves less and less room in the environment for other biota.? st century will be a pivotal time in the fate of Earth?s biosphere. Whereas human modification of the geosphere will slowly recover over time, human changes to the biosphere are a far more consequential matter? extinction of a species is forever! Will humans effectively use our new knowledge of natural and human history to stop further degradation of Earth?s ecosystems and extinction of its biota? The fate of the biosphere, including humanity, depends on a reaffirmation by all humans of all cultures and religions of the global importance of a planet-wide conservation of the Earth?s biotic heritage. For the world?s religions it means elevation of stewardship of the Earth to a moral imperative and a goal of complete preservation of the Earth?s biotic inheritance, one which is based on a Do No Harm ethic.

Open-File Report↗

USGS1999

Movement patterns and population characteristics of the Karner blue butterfly (Lycaeides melissa samuelis) at Indiana Dunes National Lakeshore

We conducted a three-year mark-release-recapture study of the endangered Karner blue butterfly (Lycaeides melissa samuelis Nabokov) at Indiana Dunes National Lakeshore to describe the butterfly's movement patterns and to assess seasonal changes in the Karner blue's population structure. Estimated mean Karner blue adult life span was less than 3.5 days. Populations exhibited protandry and about a 2:1 male:female sex ratio at population peak within a brood. Ranges, or maximum distances moved by individual butterflies, were typically less than 100 m. Maximum ranges were less than 1 km. These distances are similar to those reported for other lycaenid butterflies and from other studies of the Karner blue in the midwestern United States. At two sites, fewer than 2% of adults had ranges greater than 300 m, while at a third site 4.3% of adults had ranges greater than 300 m. Given typical subpopulation sizes these movement percentages suggest that few adults per generation will move between subpopulations separated by more than 300 m. Movement of individuals between subpopulation sites is important for maintaining genetic diversity within a metapopulation and for recolonizing areas following local extinctions. Therefore, prudent conservation planning should aim for a landscape with habitat patches suitable for Karner blue butterfly occupancy separated by less than 300 m.

Indiana↗

USGS1999

Herpetology in the federal government: a personal view

In late 1976, I received a phone call from an ichthyological colleague who asked if I would be willing to take a temporary position in the U.S. Fish and Wildlife Service's (FWS) Office of Endangered Species (OES) in Washington. They had a backlog of proposed and final rules that needed to be finished, and they thought that a 30-day stint by a temporary herpetologist would clear the slate. Thus began a 23-year odyssey through the sometimes bizarre, sometimes rewarding, sometimes discouraging, but always different federal government. Fortunately, I have been able to stay involved with herpetology, both as a science and in terms of conservation policy. In my career, I have worked both in an administrative and in a research capacity. Many individuals with an interest in herpetology enter the federal government as field biologists and drift into administration as they become older and removed from the dynamically changing nature of their science. I moved in the other direction.

Herpetologists' League Communications↗

USGS2018

High resolution measurement of levee subsidence related to energy infrastructure in the Sacramento-San Joaquin Delta

We assess flood overtopping potential (when flood water elevation exceeds levee elevation) to the levees surrounding the islands in the interior of California's Sacramento-San Joaquin Delta. Because critical natural gas infrastructure is susceptible to overtopping-related disruption, we focus our analysis on regions that are crossed by the network of the state's natural gas pipelines. We use laser scanning data collected during 2015-2016 to estimate subsidence rates since 2007 when an earlier, Delta-wide, airborne laser-scanning topographic dataset was collected. For each levee studied, we combine: (1) the estimated subsidence rate, (2) a conservative range of sea-level rise projections and, (3) an estimate of the 100-year freshwater flood stage to project the time until exceedance of the federal levee height standard (PL84-99). We find that subsidence rates vary from 0-5 centimeters per year (cm/yr) with mean values of ~1-2 cm/year. Local gradients in subsidence can be on the order of cms/yr over a distance of 10s of meters parallel to the levee crests, and these types of gradients are present near some pipeline crossings. The Sherman Island region has subsidence rates close to a factor of 2 greater than other areas considered. Our projections indicate general ranges of exceedance date from about 2060 (fast sea-level rise scenario) to 2080 (slow sea-level rise scenario) with some places projected to exceed threshold by about 2050.

California↗

USGS2021

Alaska Landbird Conservation Plan

Alaska is a land of extremes. The diversity of its avifauna reflects the heterogeneity of its landscape, with more than 500 species of birds recorded in the state. Species inhabiting primarily terrestrial habitats, known collectively as landbirds, constitute the largest and most ecologically diverse component of the Alaska avifauna. Habitats used by landbirds range from temperate rainforests in southeastern Alaska to Arctic tundra across much of northern Alaska. Most of these landbird species are migratory, and four major global migration flyways converge on rich breeding areas in Alaska. Alaska has one endemic landbird species, the McKay’s Bunting, and is home to an impressive number of landbird populations for which it hosts a large proportion of the regional, continental, or global population. Thus, Alaska has a significant stewardship responsibility for these particular landbird species and subspecies. Habitats in Alaska remain largely pristine due to the region’s remote nature, vast size, and small human population. Alaska’s growing population and attendant economic development, however, present many challenges that could affect all wildlife, including landbirds. Threats in Alaska are often considered to be less significant than those occurring elsewhere, where habitats are being altered by more rapidly increasing anthropogenic pressures, but they carry far-reaching consequences nonetheless. Habitats and ecosystem dynamics are changing rapidly due to the magnitude of climate warming at high latitudes. As such, effective landbird conservation in Alaska requires a broad, landscape-scale approach. Conservation of landbirds over such an extensive and diverse landscape also demands that we integrate efforts in habitat management, population monitoring, research, education, and outreach at local, regional, continental, and international scales. Information on distribution and habitat requirements of landbirds should be incorporated into land-use planning decisions. Synthesizing information on distribution and population trends of landbirds is a critical, time-sensitive task. Such information should be provided in a form that is readily available to land managers and policy decision-makers. The primary objectives of this plan are to (1) describe the region and Alaska’s landbird avifauna; (2) identify species of concern, important habitats, and key information needs; (3) highlight major conservation issues and threats to landbirds; and (4) identify potential conservation actions. We first examine landbird conservation at the statewide level within broad perspectives (regional, continental, and global), then take a detailed look at the specific issues, information needs, and potential conservation actions within each Bird Conservation Region in Alaska.

Alaska↗

USGS2026

Long-term predictive modeling of stream condition suggests wide-spread changes within the Chesapeake Bay Watershed, USA

Stream ecosystems worldwide face ongoing degradation, underscoring the urgent need for conservation and restoration. Regional analyses of stream condition have been limited by sparse spatial and temporal data, particularly at long time scales. To address this gap, we used observed data to predict annual biological condition for 360,893 small, nontidal stream reaches in the Chesapeake Bay watershed from 1985 to 2023 (39 years). Predictions were generated using random forest models trained on extensive benthic macroinvertebrate data sets and predictors including natural landscape features, land cover, and climate variables. Four biological metrics were assessed: percent Ephemeroptera, Plecoptera, and Trichoptera excluding Hydropsychidae (EPT-H), percent Ephemeroptera, percent clinger functional group, and the Index of Biological Integrity (IBI). Results revealed degraded biological conditions near Washington, D.C. and Baltimore, Maryland, with declining trends across all metrics in these urbanized areas. Spatial heterogeneity was evident: IBI and clinger percentages increased in many southern streams but declined in northern streams, whereas EPT-H and Ephemeroptera decreased watershed wide except in the Southeastern Plains bioregion. By 2021, watershed wide IBI improvements were predicted for 0.9–1.1% of stream length, falling short of management goals. This study demonstrates the utility of long-term data and machine learning for predicting stream condition, identifying key stressors, and guiding restoration and conservation site selection.

Delaware, Maryland, New York, Pennsylvania, Virgin↗

USGS2016

Effects of haying on breeding birds in CRP grasslands

The Conservation Reserve Program (CRP) is a voluntary program that is available to agricultural producers to help protect environmentally sensitive or highly erodible land. Management disturbances of CRP grasslands generally are not allowed unless authorized to provide relief to livestock producers during severe drought or a similar natural disaster (i.e., emergency haying and grazing) or to improve the quality and performance of the CRP cover (i.e., managed haying and grazing). Although CRP grasslands may not be hayed or grazed during the primary bird-nesting season, these disturbances may have short-term (1 yr after disturbance) and long-term (≥2 yr after disturbance) effects on grassland bird populations. We assessed the effects of haying on 20 grassland bird species in 483 CRP grasslands in 9 counties of 4 states in the northern Great Plains, USA between 1993 and 2008. We compared breeding bird densities (as determined by total-area counts) in idle and hayed fields to evaluate changes 1, 2, 3, and 4 years after haying. Haying of CRP grasslands had either positive or negative effects on grassland birds, depending on the species, the county, and the number of years after the initial disturbance. Some species (e.g., horned lark [ Eremophila alpestris ], bobolink [ Dolichonyx oryzivorus ]) responded positively after haying, and others (e.g., song sparrow [ Melospiza melodia ]) responded negatively. The responses of some species changed direction as the fields recovered from haying. For example, densities for common yellowthroat ( Geothlypis trichas ), sedge wren ( Cistothorus platensis ), and clay-colored sparrow ( Spizella pallida ) declined the first year after haying but increased in the subsequent 3 years. Ten species showed treatment × county interactions, indicating that the effects of haying varied geographically. This long-term evaluation on the effects of haying on breeding birds provides important information on the strength and direction of changes in bird populations following a disturbance. Results from this study can help guide management of CRP and other grasslands and inform future agricultural programs that address biomass energy production. © 2016 This article is a U.S. Government work and is in the public domain in the USA.

Minnesota, Montana, North Dakota, South Dakota↗

USGS2019

Quantifying ecological integrity of terrestrial systems to inform management of multiple-use public lands in the United States

The concept of ecological integrity has been applied widely to management of aquatic systems, but still is considered by many to be too vague and difficult to quantify to be useful for managing terrestrial systems, particularly across broad areas. Extensive public lands in the western United States are managed for diverse uses such as timber harvest, livestock grazing, energy development, and wildlife conservation, some of which may degrade ecological integrity. We propose a method for assessing ecological integrity on multiple-use lands that identifies the components of integrity and levels in the ecological hierarchy where the assessment will focus, and considers existing policies and management objectives. Both natural reference and societally desired environmental conditions are relevant comparison points. We applied the method to evaluate the ecological integrity of shrublands in Nevada, yielding an assessment based on six indicators of ecosystem structure, function, and composition, including resource- and stressor-based indicators measured at multiple scales. Results varied spatially and among indicators. Invasive plant cover and surface development were highest in shrublands in northwest and southeast Nevada. Departure from reference conditions of shrubland area, composition, patch size, and connectivity was highest in central and northern Nevada. Results may inform efforts to control invasive species and restore shrublands on federal lands in Nevada. We suggest that ecological integrity assessments for multiple-use lands be grounded in existing policies and monitoring programs, incorporate resource- and stressor-based metrics, rely on publicly available data collected at multiple spatial scales, and quantify both natural reference and societally desired resource conditions.

Nevada↗

USGS2026

Global change and threats to waterbirds in the Asian flyways

Avian migration represents one of nature’s most spectacular phenomena, providing critical ecological services and acting as an indicator of environmental change. Flyways are geographical ranges through which migrating bird species move, and the flyway concept has been used to identify countries that share species to highlight their collective responsibility for conservation. Of the nine recognized global waterbird flyways, the Central Asian Flyway (CAF) and the East Asian–Australasian Flyway (EAAF) are among the most important areas in Eurasia, supporting millions of waterbirds across a vast network of habitats. We proposed this special issue in Avian Research entitled “Global Change and Threats to Waterbirds in the Asian Flyways” to synthesize recent findings from 12 papers covering a wide range of topics. The CAF stretches from the Siberian tundra through Central Asia including Mongolia, the Qinghai-Tibet Plateau, the Trans-Caucasus, and the Himalayas, extending south to the Indian subcontinent and parts of the Middle East. The EAAF spans eastern Siberia and Alaska to Southeast Asia, Australia, and New Zealand, including China, Japan, the Korean Peninsula, and the Russian Far East. These two flyways include 47 countries comprising critical wetlands, river basins, and coastal areas, which are vital breeding, stopover, and wintering grounds for waterbirds. Seasonal migration in these flyways is fundamentally influenced by climate and weather conditions, land cover dynamics, and anthropogenic activities, and contributes significantly to ecological processes such as pest control, nutrient cycling, and organism dispersal. However, migratory waterbirds and their habitats are undergoing enormous challenges. Changes in climate, habitat availability and connectivity, and human activities are altering the phenology, distribution, population dynamics, and health of the migratory bird populations. As migratory waterbirds travel across international boundaries, understanding their movements and responses to environmental change requires collaborative, cross-border research efforts that promote knowledge sharing and interdisciplinary approaches.

Avian Research↗

USGS2011

Sulfur in the South Florida ecosystem: Distribution, sources, biogeochemistry, impacts, and management for restoration

Sulfur is broadly recognized as a water quality issue of significance for the freshwater Florida Everglades. Roughly 60% of the remnant Everglades has surface water sulfate concentrations above 1 mg l-1, a restoration performance measure based on present sulfate levels in unenriched areas. Highly enriched marshes in the northern Everglades have average sulfate levels of 60 mg l-1. Sulfate loading to the Everglades is principally a result of land and water management in South Florida. The highest concentrations of sulfate (average 60-70 mg l-1) in the ecosystem are in canal water in the Everglades Agricultural Area (EAA). Potential sulfur sourcesin the watershed are many, but geochemical data and a preliminary sulfur mass balance for the EAA are consistent with sulfur presently used in agricultural, and sulfur released by oxidation of organic EAA soils (including legacy agricultural applications and natural sulfur) as the primary sources of sulfate enrichment in the EAA canals. Sulfate loading to the Everglades increases microbial sulfate reduction in soils, leading to more reducing conditions, greater cycling of nutrients in soils, production of toxic sulfide, and enhanced methylmercury (MeHg) production and bioaccumulation. Wetlands are zones of naturally high MeHg production, but the combination of high atmospheric mercury deposition rates in South Florida and elevated sulfate loading leads to increased MeHg production and MeHg risk to Everglades wildlife and human consumers. Sulfate from the EAA drainage canals penetrates deep into the Everglades Water Conservation Areas, and may extend into Everglades National Park. Present plans to restore sheet flow and to deliver more water to the Everglades may increase overall sulfur loads to the ecosystem, and move sulfate-enriched water further south. However, water management practices that minimize soil drying and rewetting cycles can mitigate sulfate release during soil oxidation. A comprehensive Everglades restoration strategy should include reduction of sulfur loads as a goal because of the many detrimental impacts of sulfate on the ecosystem. Monitoring data show that the ecosystem response to changes in sulfate levels is rapid, and strategies for reducing sulfate loading may be effective in the near term. A multifaceted approach employing best management practices for sulfur in agriculture, agricultural practices that minimize soil oxidation, and changes to stormwater treatment areas that increase sulfate retention could help achieve reduced sulfate loads to the Everglades, with resulting benefits.

Florida↗