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USGS2019

Rigorously valuing the role of U.S. coral reefs in coastal hazard risk reduction

The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards. The protective services of these natural defenses are not assessed in the same rigorous economic terms as artificial defenses, such as seawalls, and therefore often are not considered in decision making. Here we combine engineering, ecologic, geospatial, social, and economic tools to provide a rigorous valuation of the coastal protection benefits of all U.S. coral reefs in the States of Hawaiʻi and Florida, the territories of Guam, American Samoa, Puerto Rico, and Virgin Islands, and the Commonwealth of the Northern Mariana Islands. We follow risk-based valuation approaches to map flood zones at 10-square-meter resolution along all 3,100+ kilometers of U.S. reef-lined shorelines for different storm probabilities to account for the effect of coral reefs in reducing coastal flooding. We quantify the coastal flood risk reduction benefits provided by coral reefs across storm return intervals using the latest information from the U.S. Census Bureau, Federal Emergency Management Agency, and Bureau of Economic Analysis to identify their annual expected benefits, a measure of the annual protection provided by coral reefs. Based on these results, the annual protection provided by U.S. coral reefs is estimated in: avoided flooding to more than 18,180 people; avoided direct flood damages of more than \$825 million to more than 5,694 buildings; avoided flooding to more than 33 critical infrastructure facilities, including essential facilities, utility systems, and transportation systems; and avoided indirect damages of more than \$699 million in economic activity of individuals and more than \$272 million in avoided business interruption annually. Thus, the annual value of flood risk reduction provided by U.S. coral reefs is more than 18,000 lives and \$1.805 billion in 2010 U.S. dollars. These data provide stakeholders and decision makers with spatially explicit, rigorous valuation of how, where, and when U.S. coral reefs provide critical coastal storm flood reduction benefits. The overall goal is to ultimately reduce the risk to, and increase the resiliency of, U.S. coastal communities.

American Samoa, Commonwealth of the Northern Maria↗

USGS2018

Disentangling the effects of low pH and metal mixture toxicity on macroinvertebrate diversity

One of the primary goals of biological assessment of streams is to identify which of a suite of chemical stressors is limiting their ecological potential. Elevated metal concentrations in streams are often associated with low pH, yet the effects of these two potentially limiting factors of freshwater biodiversity are rarely considered to interact beyond the effects of pH on metal speciation. Using a dataset from two continents, a biogeochemical model of the toxicity of metal mixtures (Al, Cd, Cu, Pb, Zn) and quantile regression, we addressed the relative importance of both pH and metals as limiting factors for macroinvertebrate communities. Current environmental quality standards for metals proved to be protective of stream macroinvertebrate communities and were used as a starting point to assess metal mixture toxicity. A model of metal mixture toxicity accounting for metal interactions was a better predictor of macroinvertebrate responses than a model considering individual metal toxicity. We showed that the direct limiting effect of pH on richness was of the same magnitude as that of chronic metal toxicity, independent of its influence on the availability and toxicity of metals. By accounting for the direct effect of pH on macroinvertebrate communities, we were able to determine that acidic streams supported less diverse communities than neutral streams even when metals were below no-effect thresholds. Through a multivariate quantile model, we untangled the limiting effect of both pH and metals and predicted the maximum diversity that could be expected at other sites as a function of these variables. This model can be used to identify which of the two stressors is more limiting to the ecological potential of running waters.

Environmental Pollution↗

USGS2012

Species richness effects on ecosystem multifunctionality depend on evenness, composition and spatial pattern

1. Recent studies have suggested that the simultaneous maintenance of multiple ecosystem functions (multifunctionality) is positively supported by species richness. However, little is known regarding the relative importance of other community attributes (e.g. spatial pattern, species evenness) as drivers of multifunctionality. 2. We conducted two microcosm experiments using model biological soil crust communities dominated by lichens to: (i) evaluate the joint effects and relative importance of changes in species composition, spatial pattern (clumped and random distribution of lichens), evenness (maximal and low evenness) and richness (from two to eight species) on soil functions related to nutrient cycling (β-glucosidase, urease and acid phosphatase enzymes, in situ N availability, total N, organic C, and N fixation), and (ii) assess how these community attributes affect multifunctionality. 3. Species richness, composition and spatial pattern affected multiple ecosystem functions (e.g. organic C, total N, N availability, β-glucosidase activity), albeit the magnitude and direction of their effects varied with the particular function, experiment and soil depth considered. Changes in species composition had effects on organic C, total N and the activity of β-glucosidase. Significant species richness × evenness and spatial pattern × evenness interactions were found when analysing functions such as organic C, total N and the activity of phosphatase. 4. The probability of sustaining multiple ecosystem functions increased with species richness, but this effect was largely modulated by attributes such as species evenness, composition and spatial pattern. Overall, we found that model communities with high species richness, random spatial pattern and low evenness increased multifunctionality. 5. Synthesis. Our results illustrate how different community attributes have a diverse impact on ecosystem functions related to nutrient cycling, and provide new experimental evidence illustrating the importance of the spatial pattern of organisms on ecosystem functioning. They also indicate that species richness is not the only biotic driver of multifunctionality, and that particular combinations of community attributes may be required to maximize it.

Journal of Ecology↗

USGS2019

Phytoplankton community structure response to groundwater-borne nutrients in the inland bays, Delaware

To determine the impacts of groundwater-borne nutrients on phytoplankton biomass and community structure, we conducted a series of mesocosm experiments in the Inland Bays of Delaware. Four treatments were tested, including mesocosms coupled directly to submarine groundwater seepage, mesocosms with the addition of pumped submarine groundwater, mesocosms with the addition of phosphate, and control mesocosms with no nutrient addition. We measured chlorophyll a concentrations as a proxy for overall biomass and used genetic sequencing techniques to characterize the phytoplankton community structure. Groundwater carried a high N load to the estuary with NO 3 - up to 295 µmol l -1 and NH 4 + up to 55 µmol l -1 . As a result, treatment mesocosms had elevated NO 3 - and NH 4 + , while control mesocosms were relatively low in nutrients. In June, the highest chlorophyll a concentrations occurred in mesocosms attached to seepage meters after 3.5 d, with significant differences across all treatments. In August, groundwater-amended mesocosms reached the highest biomass concentrations, which peaked after 3 d. There were significant differences across all treatments, except control and phosphate-amended mesocosms which remained unchanged. Community sequence data showed that species assemblage was also impacted by availability of nutrients, with significant differences in community structure for mesocosms receiving nutrients vs. control mesocosms in both June and August experiments. Harmful algal species proliferated in high nutrient treatments, including Cylindrotheca closterium , Karlodinium veneficum , Nitzschia spp., and Heterocapsa spp. While the general relationship between nutrient supply and biomass production is well known, we demonstrate the role groundwater-borne nutrients and sediment processes play in shaping community structure in estuarine primary producers and in promoting harmful algal blooms.

Delaware↗

USGS2024

Establishment of terrestrial mammals on former reservoir beds following large dam removal on the Elwha River, Washington, USA

Terrestrial wildlife species are important yet often overlooked taxa in the recovery of ecosystems following dam removal. Their presence can shape ecosystem recovery, signal restoration of ecosystem function, and influence food web dynamics and nutrient transfer. We used camera traps to examine seasonal use of two former reservoir beds and an upstream reference reach by the mammalian community following the removal of two large dams on the Elwha River, Washington, USA. For certain taxa, we compared current species use to data collected prior to dam removal. Camera traps revealed use by at least fifteen mammal species, including but not limited to American black bear ( Ursus americanus ), Columbian black-tailed deer ( Odocoileus hemionus columbianus ), Roosevelt elk ( Cervus elaphus roosevelti ), puma ( Puma concolor ), coyotes ( Canis latrans ), bobcats ( Lynx rufus ), and snowshoe hares ( Lepus americanus ). Coyotes were found mostly lower in the watershed outside the Olympic National Park boundary, while other species were distributed throughout the restoration area. We did not see major differences in species composition between the restoration areas and the upstream reference reach, though number of detections across study reaches differed for most species. Unlike previous findings, black bears were observed across all seasons in this study, suggesting a shift in seasonal use since dam removal. Full restoration of the terrestrial wildlife community could take decades to unfold, but early patterns demonstrate rapid establishment and use by wildlife on new riparian surfaces that are expected to continue to evolve with restoration of fish and vegetation communities.

Washingotn↗

USGS2020

The abundance of Greater Sage-Grouse as a proxy for the abundance of sagebrush-associated songbirds in Wyoming, USA

Surrogate-species concepts are prevalent in animal conservation. Such strategies advocate for conservation by proxy, wherein one species is used to represent other taxa to obtain a conservation objective. The efficacy of such approaches has been rarely assessed empirically, but is predicated on concordance between the surrogate and sympatric taxa in distribution, abundance, and ecological requirements. Our objective was to identify whether the abundance of a high-profile umbrella species (Greater Sage-Grouse, Centrocercus urophasianus , hereafter sage-grouse) was associated with the abundance of six other members of the avian community for which it is presumed to be a surrogate, including three sagebrush-obligate and three sagebrush-associated songbird species. We predicted that sage-grouse abundance would align most closely with the breeding abundance of other sagebrush-obligate birds. We used two different indices of sage-grouse abundance for comparisons: field-collected counts of fecal pellets (primarily indexing abundance in the nonbreeding season) and a spatially explicit index of breeding population size. Neither index of sage-grouse abundance was consistently predictive of co-occurring songbird abundance, with one species more abundant (Horned Lark [ Eremophila alpestris ]) and one species less abundant (Vesper Sparrow [ Pooecetes gramineus ]) where sage-grouse pellet counts were higher, and no relationship evident between songbird abundance and the spatially explicit sage-grouse population index. Ours is one of few assessments of the efficacy of sage-grouse as a surrogate species to consider abundance, and not habitat overlap alone. We suggest that the utility of sage-grouse as a surrogate species likely varies across spatial scales. Within the scale examined here (10–15 ha sites), however, indices of sage-grouse abundance were unreliable proxies for the abundance of six declining songbird species.

Wyoming↗

USGS2014

Trends in conservation research and management in Hawai‘i over the past 20 years

Hawaiʻi, an archipelago of the most isolated inhabited islands on the planet, faces unique and extreme challenges to its biodiversity. We examined how the conservation community has responded to these challenges and how the responses have changed over time, using twenty years of abstracts from the Hawaiʻi Conservation Conference, a yearly gathering of the majority of scientists, managers and the public in Hawaiʻi. Of the 2145 abstracts considered, 60% percent reported research results; 40.0% reported information on conservation and resource management programmes and institutions (i.e., non-research abstracts). Initially, applied research abstracts predominated, but in recent years the number of basic research abstracts has become similar. Across taxonomic groups, terrestrial plants, mammals and birds were the dominant research subjects, fish, algae and fungi were noticeably less studied relative to their diversity in Hawaiʻi. Bird and fish species studied were mostly native; research on most other taxa was evenly divided between native and non-native species. Topics have oscillated in frequency over the years, but there have been no dramatic trends, with the exception of climate change and Local Ecological Knowledge (LEK). Although there is an increasing trend in LEK and cross-disciplinary studies, the number of related abstracts have remained uncommon through the period, accounting for less than 5.0% of total research abstracts analyzed. Our results offer an oportunity for the conservation community to take a closer look at reported effort to better address key conservation questions for Hawaiʻi.

Hawaiʻi↗

USGS2009

Culture-independent characterization of bacterial communities associated with the cold-water coral Lophelia pertusa in the northeastern Gulf of Mexico

Bacteria are recognized as an important part of the total biology of shallow-water corals. Studies of shallow-water corals suggest that associated bacteria may benefit the corals by cycling carbon, fixing nitrogen, chelating iron, and producing antibiotics that protect the coral from other microbes. Cold-water or deep-sea corals have a fundamentally different ecology due to their adaptation to cold, dark, high-pressure environments and as such have novel microbiota. The goal of this study was to characterize the microbial associates of Lophelia pertusa in the northeastern Gulf of Mexico. This is the first study to collect the coral samples in individual insulated containers and to preserve coral samples at depth in an effort to minimize thermal shock and evaluate the effects of environmental gradients on the microbial diversity of samples. Molecular analysis of bacterial diversity showed a marked difference between the two study sites, Viosca Knoll 906/862 (VK906/862) and Viosca Knoll 826 (VK826). The bacterial communities from VK826 were dominated by a variety of unknown mycoplasmal members of the Tenericutes and Bacteroidetes , whereas the libraries from VK906/862 were dominated by members of the Proteobacteria . In addition to novel sequences, the 16S rRNA gene clone libraries revealed many bacterial sequences in common between Gulf of Mexico Lophelia corals and Norwegian fjord Lophelia corals, as well as shallow-water corals. Two Lophelia -specific bacterial groups were identified: a cluster of gammaproteobacteria related to sulfide-oxidizing gill symbionts of seep clams and a group of Mycoplasma spp. The presence of these groups in both Gulf and Norwegian Lophelia corals indicates that in spite of the geographic heterogeneity observed in Lophelia -associated bacterial communities, there are Lophelia -specific microbes.

Gulf of Mexico↗

USGS2007

Hydrologic connectivity and the contribution of stream headwaters to ecological integrity at regional scales

Cumulatively, headwater streams contribute to maintaining hydrologic connectivity and ecosystem integrity at regional scales. Hydrologic connectivity is the water-mediated transport of matter, energy and organisms within or between elements of the hydrologic cycle. Headwater streams compose over two-thirds of total stream length in a typical river drainage and directly connect the upland and riparian landscape to the rest of the stream ecosystem. Altering headwater streams, e.g., by channelization, diversion through pipes, impoundment and burial, modifies fluxes between uplands and downstream river segments and eliminates distinctive habitats. The large-scale ecological effects of altering headwaters are amplified by land uses that alter runoff and nutrient loads to streams, and by widespread dam construction on larger rivers (which frequently leaves free-flowing upstream portions of river systems essential to sustaining aquatic biodiversity). We discuss three examples of large-scale consequences of cumulative headwater alteration. Downstream eutrophication and coastal hypoxia result, in part, from agricultural practices that alter headwaters and wetlands while increasing nutrient runoff. Extensive headwater alteration is also expected to lower secondary productivity of river systems by reducing stream-system length and trophic subsidies to downstream river segments, affecting aquatic communities and terrestrial wildlife that utilize aquatic resources. Reduced viability of freshwater biota may occur with cumulative headwater alteration, including for species that occupy a range of stream sizes but for which headwater streams diversify the network of interconnected populations or enhance survival for particular life stages. Developing a more predictive understanding of ecological patterns that may emerge on regional scales as a result of headwater alterations will require studies focused on components and pathways that connect headwaters to river, coastal and terrestrial ecosystems. Linkages between headwaters and downstream ecosystems cannot be discounted when addressing large-scale issues such as hypoxia in the Gulf of Mexico and global losses of biodiversity.

Journal of the American Water Resources Associatio↗

USGS2024

Food-web dynamics of a floodplain mosaic overshadow the effects of engineered logjams for Pacific salmon and steelhead

Food webs vary in space and time. The structure and spatial arrangement of food webs are theorized to mediate temporal dynamics of energy flow, but empirical corroboration in intermediate-scale landscapes is scarce. River-floodplain landscapes encompass a mosaic of aquatic habitat patches and food webs, supporting a variety of aquatic consumers of conservation concern. How the structure and productivity of these patch-scale food webs change through time, and how floodplain restoration influences their dynamics, are unevaluated. We measured productivity and food-web dynamics across a mosaic of main-channel and side-channel habitats of the Methow River, WA, USA, during two study years (2009–2010; 2015–2016) and examined how food webs that sustained juvenile anadromous salmonids responded to habitat manipulation. By quantifying temporal variation in secondary production and organic matter flow across nontreated river-floodplain habitats and comparing that variation to a side channel treated with engineered logjams, we jointly confronted spatial food-web theory and assessed whether food-web dynamics in the treated side channel exceeded natural variation exhibited in nontreated habitats. We observed that organic matter flow through the more complex, main-channel food web was similar between study years, whereas organic matter flow through the simpler, side-channel food webs changed up to ~4-fold. In the side channel treated with engineered logjams, production of benthic invertebrates and juvenile salmonids increased between study years by 2× and 4×, respectively; however, these changes did not surpass the temporal variation observed in untreated habitats. For instance, juvenile salmonid production rose 17-fold in one untreated side-channel habitat, and natural aggregation of large wood in another coincided with a shift to community and food-web dominance by juvenile salmonids. Our findings suggest that interannual dynamism in material flux across floodplain habitat mosaics is interrelated with patchiness in food-web complexity and may overshadow the ecological responses to localized river restoration. Although this dynamism may inhibit detection of the ecological effects of river restoration, it may also act to stabilize aquatic ecosystems and buffer salmon and other species of conservation concern in the long term. As such, natural, landscape-level patchiness and dynamism in food webs should be integrated into conceptual foundations of process-based, river restoration.

Washington↗

USGS2010

Evaluating ecological equivalence of created marshes: comparing structural indicators with stable isotope indicators of blue crab trophic support

This study sought to examine ecological equivalence of created marshes of different ages using traditional structural measures of equivalence, and tested a relatively novel approach using stable isotopes as a measure of functional equivalence. We compared soil properties, vegetation, nekton communities, and δ 13 C and δ 15 N isotope values of blue crab muscle and hepatopancreas tissue and primary producers at created (5-24 years old) and paired reference marshes in SW Louisiana. Paired contrasts indicated that created and reference marshes supported equivalent plant and nekton communities, but differed in soil characteristics. Stable isotope indicators examining blue crab food web support found that the older marshes (8 years+) were characterized by comparable trophic diversity and breadth compared to their reference marshes. Interpretation of results for the youngest site was confounded by the fact that the paired reference, which represented the desired end goal of restoration, contained a greater diversity of basal resources. Stable isotope techniques may give coastal managers an additional tool to assess functional equivalency of created marshes, as measured by trophic support, but may be limited to comparisons of marshes with similar vegetative communities and basal resources, or require the development of robust standardization techniques.

Estuaries and Coasts↗

USGS2021

Mangroves and people: Impacts and interactions

Mangroves have long been associated with human populations, as coastal communities rely on the various ecosystem services that mangroves provide. However, human degradation and destruction of mangrove forests is common, despite and because of our reliance on them as valuable ecosystems. Mangrove research and management must elucidate and reconcile these conflicts to maintain mangrove forests and the services that humans depend on. To better understand the complex dynamics, interactions and relationships that exist between mangroves and coastal communities, the 5th Mangrove Macrobenthos and Management (MMM5) conference was held in Singapore in July 2019, with the theme “ Mangroves and People: Impacts and Interactions”. This theme was chosen because Southeast Asia is the epicentre of ongoing mangrove loss, and a large number of coastal communities in the region rely on the ecosystem services that mangroves provide. The 32 papers published in this Special Issue represent the breadth of mangrove research presented at MMM5, including topics in faunal biology, ecosystem ecology, genetics, physical geography, biogeochemistry, remote sensing and the social sciences. The articles are characterized under the following topics: 1) mangrove ecosystem functioning; 2) range expansion of mangroves; 3) ecosystem services of mangroves; 4) anthropogenic and natural threats to mangroves; and 5) the management and social-ecology of mangroves. This Special Issue highlights the current state of the art of mangrove research and application, and describes a number of emerging new ideas and research opportunities that will continue to advance mangrove ecosystem science into the future.

Estuarine, Coastal and Shelf Science↗

USGS1986

Benthic invertebrate population characteristics as affected by water quality in coal-bearing regions of Tennessee

Benthic invertebrate and water quality data collected during previous U.S. Geological Survey studies to provide background hydrologic information on streams draining Tennessee coal reserves, were evaluated to identify possible relations between stream biota and water quality. Linear regressions produced low correlation coefficients relating the number of taxa/sample, total number of organisms/sample, sample diversity, and percentage composition of selected orders of invertebrates, with average water quality parameter values available at sampling stations (r is < 0.62 at p=0.05). Analyses of these data by linear regressions explained little of the variability in benthic invertebrate samples primarily because the distributions of benthic organisms along environmental gradients are nonlinear. Variability in substrate characteristics in the study area and seasonal insect emergence patterns also complicated interpretation of these data. However, analysis of variance tests did indicate significant trends towards reduced number of taxa, number of organisms, and sample diversity at stations with relatively poor water quality conditions. Decreasing percentage composition of Ephemeroptera was generally accompanied by an increase in percent Diptera at stations with higher water quality constituent concentrations and acidic pH (> than 0.6 units). These trends indicate significant differences in benthic communities at sites with evidence of more severe land use impacts. Additional data on benthic invertebrates, water quality, and physical habitat conditions, along with analyses of data using multivariate statistical methods are needed to define ecological relations between specific groups of invertebrates and environmental conditions.

Tennessee↗

USGS2006

Range expansion of an exotic Siberian prawn to the Lower Snake River

The introduction of non-native plant and animal species in aquatic systems is of increasing concern because of their potentially negative ecological and economic impacts (Sytsma et al. 2004). There are many examples of food web repercussions resulting from non-native invertebrate introductions. For example, in Flathead Lake, Montana, the kokanee salmon (Oncorhynchus nerka) population crashed after the introduction of a planktivorous mysid, My-sis relicta caused restructuring of the zooplankton community (Spencer et al. 1991) and the introduc-tion of the spiny water flea (Bythotrephes spp.) to the Great Lakes also restructured zooplankton communities (Barbiero and Tuchman 2004). The zebra mussel (Dreissena polymorpha) has nearly extirpated some native unionid clams through competition for food and shell fouling (Strayer 1999). In San Francisco Bay, California, one of the most highly invaded estuaries in the world (Cohen and Carlton 1998), the benthic fauna has been highly modified by the introduction of hundreds of exotic invertebrates including the Chinese mitten crab (Eriocheir sinensis) and the Asian clam, Potamocorbula amurensis. Non-native invertebrate species, including the New Zealand mud snail (Potamopyrgus antipodarum) and an-other Asian clam, Corbicula fluminea, have also been introduced to the Columbia River (Sytsma et al. 2004), but the ecological effects to Columbia River species are largely unknown.

Washington↗

USGS2010

Alteration of streamflow magnitudes and potential ecological consequences: A multiregional assessment

Human impacts on watershed hydrology are widespread in the US, but the prevalence and severity of stream-flow alteration and its potential ecological consequences have not been quantified on a national scale. We assessed streamflow alteration at 2888 streamflow monitoring sites throughout the conterminous US. The magnitudes of mean annual (1980–2007) minimum and maximum streamflows were found to have been altered in 86% of assessed streams. The occurrence, type, and severity of streamflow alteration differed markedly between arid and wet climates. Biological assessments conducted on a subset of these streams showed that, relative to eight chemical and physical covariates, diminished flow magnitudes were the primary predictors of biological integrity for fish and macroinvertebrate communities. In addition, the likelihood of biological impairment doubled with increasing severity of diminished streamflows. Among streams with diminished flow magnitudes, increasingly common fish and macroinvertebrate taxa possessed traits characteristic of lake or pond habitats, including a preference for fine-grained substrates and slow-moving currents, as well as the ability to temporarily leave the aquatic environment.

Frontiers in Ecology and the Environment↗

USGS2018

Anticipatory natural resource science and management for a changing future

Prolonged shifts in long‐term average climate conditions and increasing variability in short‐term weather conditions affect ecological processes, and represent a fundamental challenge for natural resource management. Recent and forthcoming advances in climate predictability may offer novel opportunities, but capitalizing on these opportunities will require focusing scientific research on understanding the links between climate and ecological responses over multiple timescales, fostering programmatic links among science and management agencies, and developing new and flexible decision‐making frameworks. Anticipating short‐ to near‐term climate conditions can help managers mitigate land degradation driven by unfavorable conditions and promote actions that make the most of favorable conditions. Similarly, anticipating long‐term, multidecadal climate trajectories can help managers to identify those species and communities that are most likely to remain viable throughout the 21st century. A focus on “anticipatory science and management” could substantially bolster natural resource planning and management but will require long‐term investment and widespread adoption.

Frontiers in Ecology and the Environment↗

USGS2013

Five-year interim report of the United States-Mexico Transboundary Aquifer Assessment Program: 2007--2012

Transboundary aquifers are an essential, and in many cases, singular source of water for United States – Mexico border communities, particularly in arid regions. Declining water levels, deteriorating water quality, and increasing use of groundwater resources by municipal, industrial, and agricultural water users on both sides of the international border have raised concerns about the long-term availability of this supply. Water quantity and quality are determining and limiting factors that ultimately control agriculture, future economic development, population growth, human health, and ecological conditions along the border. Knowledge about the extent, depletion rates, and quality of transboundary aquifers, however, is limited and, in some areas, completely absent. The U.S. – Mexico Transboundary Aquifer Assessment Act (Public Law 109-448), referred to in this report as “the Act,” was signed into law by the President of the United States on December 22, 2006, to conduct binational scientific research to systematically assess priority transboundary aquifers and to address water information needs of border communities. The Act authorizes the Secretary of the Interior, through the U.S. Geological Survey (USGS), to collaborate with the States of Arizona, New Mexico, and Texas through their Water Resources Research Institutes (WRRIs) and with the International Boundary and Water Commission (IBWC), stakeholders, and Mexican counterparts to provide new information and a scientific foundation for State and local officials to address pressing water-resource challenges along the U.S. – Mexico border.

Open-File Report↗

USGS2003

Comparing marine and terrestrial ecosystems: Implications for the design of coastal marine reserves

Concepts and theory for the design and application of terrestrial reserves is based on our understanding of environmental, ecological, and evolutionary processes responsible for biological diversity and sustainability of terrestrial ecosystems and how humans have influenced these processes. How well this terrestrial -based theory can be applied toward the design and application of reserves in the coastal marine environment depends, in part, on the degree of similarity between these systems. Several marked differences in ecological and evolutionary processes exist between marine and terrestrial ecosystems as ramifications of fundamental differences in their physical environments (i.e., the relative prevalence of air and water) and contemporary patterns of human impacts. Most notably, the great extent and rate of dispersal of nutrients, materials, holoplanktonic organisms, and reproductive propagules of benthic organisms expand scales of connectivity among near-shore communities and ecosystems . Consequently, the "openness" of marine populations, communities, and ecosystems probably has marked influences on their spatial, genetic, and trophic structures and dynamics in ways experienced by only some terrestrial species. Such differences appear to be particularly significant for the kinds of organisms most exploited and targeted for protection in coastal marine ecosystems (fishes and macroinvertebrates). These and other differences imply some unique design criteria and application of reserves in the marine environment. In explaining the implications of these differences for marine reserve design and application, we identify many of the environmental and ecological processes and design criteria necessary for consideration in the development of the analytical approaches developed elsewhere in this Special Issue.

Ecological Applications↗