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At least 865 records · Page 48Linked to original sources
USGS2014

Aragonite saturation states and nutrient fluxes in coral reef sediments in Biscayne National Park, FL, USA

Some coral reefs, such as patch reefs along the Florida Keys reef tract, are not showing significant reductions in calcification rates in response to ocean acidification. It has been hypothesized that this recalcitrance is due to local buffering effects from biogeochemical processes driven by seagrasses. We investigated the influence that pore water nutrients, dissolved inorganic carbon (DIC) and total alkalinity (TA) have on aragonite saturation states (Ω aragonite ) in the sediments and waters overlying the sediment surfaces of sand halos and seagrass beds that encircle Alinas and Anniversary reefs in Biscayne National Park. Throughout the sampling period, sediment pore waters from both bottom types had lower oxidation/reduction potentials (ORP), with lower pH relative to the sediment surface waters. The majority (86.5%) of flux rates (n = 96) for ΣNO x – , PO 4 3– , NH 4 + , SiO 2 , DIC and TA were positive, sometimes contributing significant concentrations of the respective constituents to the sediment surface waters. The Ω aragonite values in the pore waters (range: 0.18 to 4.78) were always lower than those in the overlying waters (2.40 to 4.46), and 52% (n = 48) of the values were <2.0. The DIC and TA fluxes at the sediment–water interface reduced Ω aragonite in 75% (n = 16) of the samples, but increased it in the remainder. The elevated fluxes of nutrients, DIC and TA into the sediment–water interface layer negatively alters the suitability of this zone for the settlement and development of calcifying larvae, while enhancing the establishment of algal communities.

Florida↗
USGS2006

Assessing peridomestic entomological factors as predictors for Lyme disease

The roles of entomologic risk factors, including density of nymphal blacklegged ticks ( Ixodes scapularis ), prevalence of nymphal infection with the etiologic agent ( Borrelia burgdorferi) , and density of infected nymphs, in determining the risk of human Lyme disease were assessed at residences in the endemic community of South Kingstown, RI. Nymphs were sampled between May and July from the wooded edge around 51 and 47 residential properties in 2002 and 2003, respectively. Nymphs were collected from all residences sampled. Tick densities, infection rates, and densities of infected nymphs were all significantly higher around homes reporting Lyme disease histories in 2003, while only infection rates were significantly higher in 2002. However, densities of infected nymphs did not significantly predict the probability of Lyme disease at a residence (by logistic regression) in either year. There were no significant differences in entomologic risk factors between homes with state-confirmed Lyme disease histories and homes with self-reported cases (not reported to the state health department). Therefore, although entomologic risk factors tended to be higher at residences with cases of Lyme disease, entomological indices, in the absence of human behavior measures, were not useful predictors of Lyme disease at the scale of individual residences in a tick-endemic community.

Rhode Island↗
USGS2020

A graphical causal model for resolving species identity effects and biodiversity–ecosystem function correlations

Identifying and clearly communicating the drivers of ecosystem function is a crucially important goal for both basic and applied ecology. This has proven difficult because the putative causes (e.g., environment, species identity, biodiversity, and functional traits) are numerous and correlated. The problem is exacerbated by a lack of a formal framework for unambiguously relating theoretical language to precise, quantitative expressions of that language. Using a formal framework for the graphical expression of complex causal hypotheses, we developed a causal diagram of the concepts required to comprehensively test whether hypothesized sets of functional traits mediate the relationship between community structure and ecosystem function. We then used causal analysis, simulations, and field data to develop and test analytical strategies for understanding how community structure influences ecosystem functions via functional traits. Formal causal analysis showed that biodiversity–ecosystem function correlations are non‐causal associations. Using simulations, we showed how biodiversity correlations and species identity effects can arise from misspecification or incomplete mediation by functional trait composites. We also found that different types of model misspecification result in different patterns of residuals, which may be used to diagnose gaps in functional trait hypotheses. Treating the model misspecifications eliminated associations between species identity or biodiversity and ecosystem function. Finally, we provide an example of the analysis of field data to demonstrate how to use these insights to conduct a research program that has the goal of understanding the mechanistic trait relationships that link community structure to ecosystem function.

Ecology↗
USGS2015

On underestimation of global vulnerability to tree mortality and forest die-off from hotter drought in the Anthropocene

Patterns, mechanisms, projections, and consequences of tree mortality and associated broad-scale forest die-off due to drought accompanied by warmer temperatures&mdash;&ldquo;hotter drought&rdquo;, an emerging characteristic of the Anthropocene&mdash;are the focus of rapidly expanding literature. Despite recent observational, experimental, and modeling studies suggesting increased vulnerability of trees to hotter drought and associated pests and pathogens, substantial debate remains among research, management and policy-making communities regarding future tree mortality risks. We summarize key mortality-relevant findings, differentiating between those implying lesser versus greater levels of vulnerability. Evidence suggesting lesser vulnerability includes forest benefits of elevated [CO 2 ] and increased water-use efficiency; observed and modeled increases in forest growth and canopy greening; widespread increases in woody-plant biomass, density, and extent; compensatory physiological, morphological, and genetic mechanisms; dampening ecological feedbacks; and potential mitigation by forest management. In contrast, recent studies document more rapid mortality under hotter drought due to negative tree physiological responses and accelerated biotic attacks. Additional evidence suggesting greater vulnerability includes rising background mortality rates; projected increases in drought frequency, intensity, and duration; limitations of vegetation models such as inadequately represented mortality processes; warming feedbacks from die-off; and wildfire synergies. Grouping these findings we identify ten contrasting perspectives that shape the vulnerability debate but have not been discussed collectively. We also present a set of global vulnerability drivers that are known with high confidence: (1) droughts eventually occur everywhere; (2) warming produces hotter droughts; (3) atmospheric moisture demand increases nonlinearly with temperature during drought; (4) mortality can occur faster in hotter drought, consistent with fundamental physiology; (5) shorter droughts occur more frequently than longer droughts and can become lethal under warming, increasing the frequency of lethal drought nonlinearly; and (6) mortality happens rapidly relative to growth intervals needed for forest recovery. These high-confidence drivers, in concert with research supporting greater vulnerability perspectives, support an overall viewpoint of greater forest vulnerability globally. We surmise that mortality vulnerability is being discounted in part due to difficulties in predicting threshold responses to extreme climate events. Given the profound ecological and societal implications of underestimating global vulnerability to hotter drought, we highlight urgent challenges for research, management, and policy-making communities.

Ecosphere↗
USGS2022

Ecological and socioeconomic factors associated with the human burden of environmentally mediated pathogens: A global analysis

Background Billions of people living in poverty are at risk of environmentally mediated infectious diseases—that is, pathogens with environmental reservoirs that affect disease persistence and control and where environmental control of pathogens can reduce human risk. The complex ecology of these diseases creates a global health problem not easily solved with medical treatment alone. Methods We quantified the current global disease burden caused by environmentally mediated infectious diseases and used a structural equation model to explore environmental and socioeconomic factors associated with the human burden of environmentally mediated pathogens across all countries. Findings We found that around 80% (455 of 560) of WHO-tracked pathogen species known to infect humans are environmentally mediated, causing about 40% (129 488 of 359 341 disability-adjusted life years) of contemporary infectious disease burden (global loss of 130 million years of healthy life annually). The majority of this environmentally mediated disease burden occurs in tropical countries, and the poorest countries carry the highest burdens across all latitudes. We found weak associations between disease burden and biodiversity or agricultural land use at the global scale. In contrast, the proportion of people with rural poor livelihoods in a country was a strong proximate indicator of environmentally mediated infectious disease burden. Political stability and wealth were associated with improved sanitation, better health care, and lower proportions of rural poverty, indirectly resulting in lower burdens of environmentally mediated infections. Rarely, environmentally mediated pathogens can evolve into global pandemics (eg, HIV, COVID-19) affecting even the wealthiest communities. Interpretation The high and uneven burden of environmentally mediated infections highlights the need for innovative social and ecological interventions to complement biomedical advances in the pursuit of global health and sustainability goals. Funding Bill & Melinda Gates Foundation, National Institutes of Health, National Science Foundation, Alfred P. Sloan Foundation, National Institute for Mathematical and Biological Synthesis, Stanford University, and the US Defense Advanced Research Projects Agency.

The Lancet Planetary Health↗
USGS2019

Improving ecological restoration to curb biotic invasion - A practical guide

Common practices for invasive species control and management include physical, chemical, and biological approaches. The first two approaches have clear limitations and may lead to unintended (negative) consequences, unless carefully planned and implemented. For example, physical removal rarely completely eradicates the targeted invasive species and can cause disturbances that facilitate new invasions by nonnative species from nearby habitats. Chemical treatments can harm native, and especially rare, species through unanticipated side effects. Biological methods may be classified as biocontrol and the ecological approach. Similar to physical and chemical methods, biocontrol also has limitations and sometimes leads to unintended consequences. Therefore, a relatively safer and more practical choice may be the ecological approach, which has two major components: (1) restoration of native species and (2) biomass manipulation of the restored community, such as selective grazing or prescribed burning (to achieve and maintain viable population sizes). Restoration requires well-planned and implemented planting designs that consider alpha-, beta-, and gamma-diversity and the abundance of native and invasive component species at local, landscape, and regional levels. Given the extensive destruction or degradation of natural habitats around the world, restoration could be most effective for enhancing ecosystem resilience and resistance to biotic invasions. At the same time, ecosystems in human-dominated landscapes, especially those newly restored, require close monitoring and careful intervention (e.g., through biomass manipulation), especially when successional trajectories are not moving as intended. Biomass management frequently uses prescribed burning, grazing, harvesting, and thinning to maintain overall ecosystem health and sustainability. Thus, the resulting optimal, balanced, and relatively stable ecological conditions could more effectively limit the spread and establishment of invasive species. Here we review the literature (especially within the last decade) on ecological approaches that involve biodiversity, biomass, and productivity, three key community/ecosystem variables that reciprocally influence one another. We focus on the common and most feasible ecological practices that can aid in resisting new invasions and/or suppressing the dominance of existing invasive species. We contend that, because of the strong influences from neighboring areas (i.e., as exotic species pools), local restoration and management efforts in the future need to consider the regional context and projected climate changes.

Invasive Plant Science and Management↗
USGS2021

Vegetation community monitoring: Species composition and biophysical gradients in Klamath Network parks

The Klamath Network of the National Park Service consists of six park units located in northern California and southern Oregon. The Network began implementing a vegetation monitoring protocol in 2011 to identify ecologically significant vegetation trends in the parks. The premise of the protocol is that multivariate analyses of species composition data is the most robust early detection means for identifying vegetation change over time. Here we present these community metrics, based on our initial sampling efforts. We use these metrics to establish a baseline for comparison in future trend analysis, and to evaluate the adequacy of the protocol for meeting the Network’s objectives of detecting temporal changes across contrasting vegetation types. The park landscapes were subdivided into three strata: Matrix (low- to mid-elevation upland habitats), Riparian (within 10 meters of a perennial stream), and High-Elevation (above a predefined elevation, park specific). Across the three strata, we established a total of 241 permanent plots at random locations to measure complete species composition and cover. We describe baseline biophysical conditions and relate them to the data obtained from all 241 plots using ordination analyses. The unconstrained gradient analyses were moderately robust at illustrating the relationships among plots and correlating them to environmental gradients. We also prepared species accumulation curves representing gamma diversity, which showed overall species richness, and also illustrated how well the observed vs. expected richness values of each stratum were captured by the sampling. Most park/strata were well sampled; for others, we found that additional samples would improve how well the protocol captures the vegetation composition within park/strata. Specifically, all sample frames at Whiskeytown and the High-Elevation sample frames at Lassen were not well sampled. Comparisons of alpha diversity values showed High-Elevations had the lowest diversity, while Riparian areas were by far the most diverse across all parks. The Matrix stratum at Oregon Caves National Monument was also especially diverse and had the highest Matrix alpha diversity we observed in all parks We suggest that after three rounds of sampling, the Network perform analyses to identify possible ways to improve statistical power. These options include adding sites or lengthening the sampling interval. Results of these analyses could support protocol modifications. This report on vegetation composition is the first in a series of analysis and synthesis reports. Future analysis and synthesis reports will analyze structure and function.

California, Oregon↗
USGS2025

DNA metabarcoding of biocrust lichen-forming fungi detects responses to disturbance and invasion

Biocrusts dominated by bryophytes and lichens perform important functions in dryland ecosystems but monitoring these communities can be cost prohibitive over broad scales. We explored DNA metabarcoding as a potential tool for monitoring biocrust lichen communities at a site in Washington (U.S.A.) that had already been surveyed for lichen diversity and community composition. We developed a DNA reference library using the internal transcribed spacer (ITS) region from specimens collected in the study area. We also visually estimated the abundance of lichen species or groups in 22 plots spanning a range of wildfire history and invasion by the exotic annual grass Bromus tectorum . At these plots, we collected bulk lichen community samples for metabarcoding using two approaches: small sample dishes and combined biocrust fragments collected using tweezers from all species observed. We used PacBio sequencing to simultaneously generate ITS barcode sequences for all lichen-forming fungi (LFF) present in the bulk samples, clustering similar sequences into operational taxonomic units (OTUs). Lichen communities detected visually and using DNA metabarcoding both captured a reduction of biocrust diversity and change in community composition related to the abundance of B. tectorum , suggesting that metabarcoding was able to identify the same dominant ecological pattern in biocrust lichens as visual sampling. The tweezer sampling approach captured on average 12.3 more OTUs than the dish approach and some taxa were more consistently detected by one approach or the other. After using the specimen DNA reference library to identify species associated with LFF OTUs, we determined that metabarcoding and visual sampling detected overlapping but different lichen species. Metabarcoding failed to detect common collected taxa, including: Arthonia glebosa, Candelariella spp ., Enchylium tenax, Lecanora muralis, Lecidella spp ., Leptochidium albociliatum, Massalongia carnosa, and Trapeliopsis glaucopholis. However, metabarcoding detected OTUs not visually observed in the genera Elixia, Lecanora, Lecanoropsis, Bacidina, Pyrenodesmia, Xanthocarpia, Trapelia, Verrucaria, and Verruculopsis . Furthermore, metabarcoding identified greater OTU diversity than expected within Diploschistes muscorum, Trapeliopsis bisorediata, and Trapeliopsis steppica . Our results suggest that metabarcoding alone or combined with visual methods could be a useful approach for monitoring biocrust lichen communities and their response to disturbance, invasion, and potential restoration.

Washington↗
USGS2016

Northern bobwhite breeding season ecology on a reclaimed surface mine

Surface coal mining and subsequent reclamation of surface mines have converted large forest areas into early successional vegetative communities in the eastern United States. This reclamation can provide a novel opportunity to conserve northern bobwhite ( Colinus virginianus ). We evaluated the influence of habitat management activities on nest survival, nest-site selection, and brood resource selection on managed and unmanaged units of a reclaimed surface mine, Peabody Wildlife Management Area (Peabody), in west-central Kentucky, USA, from 2010 to 2013. We compared resource selection, using discrete-choice analysis, and nest survival, using the nest survival model in Program MARK, between managed and unmanaged units of Peabody at 2 spatial scales: the composition and configuration of vegetation types (i.e., macrohabitat) and vegetation characteristics at nest sites and brood locations (i.e., microhabitat). On managed sites, we also investigated resource selection relative to a number of different treatments (e.g., herbicide, disking, prescribed fire). We found no evidence that nest-site selection was influenced by macrohabitat variables, but bobwhite selected nest sites in areas with greater litter depth than was available at random sites. On managed units, bobwhite were more likely to nest where herbicide was applied to reduce sericea lespedeza ( Lespedeza cuneata ) compared with areas untreated with herbicide. Daily nest survival was not influenced by habitat characteristics or by habitat management but was influenced by nest age and the interaction of nest initiation date and nest age. Daily nest survival was greater for older nests occurring early in the breeding season (0.99, SE < 0.01) but was lower for older nests occurring later in the season (0.08, SE = 0.13). Brood resource selection was not influenced by macrohabitat or microhabitat variables we measured, but broods on managed units selected areas treated with herbicide to control sericea lespedeza and were located closer to firebreaks and disked native-warm season grass stands than would be expected at random. Our results suggest the vegetation at Peabody was sufficient without manipulation to support nesting and brood-rearing northern bobwhite at a low level, but habitat management practices improved vegetation for nesting and brood-rearing resource selection. Reproductive rates (e.g., nest survival and re-nesting rates) at Peabody were lower than reported in other studies, which may be related to nutritional deficiencies caused by the abundance of sericea lespedeza. On reclaimed mine lands dominated by sericea lespedeza, we suggest continuing practices such as disking and herbicide application that are targeted at reducing sericea lespedeza to improve the vegetation for nesting and brood-rearing bobwhite.

Kentucky↗
USGS2017

Food-web dynamics and isotopic niches in deep-sea communities residing in a submarine canyon and on the adjacent open slopes

Examination of food webs and trophic niches provide insights into organisms' functional ecology, yet few studies have examined trophodynamics within submarine canyons, where the interaction of canyon morphology and oceanography influences habitat provision and food deposition. Using stable isotope analysis and Bayesian ellipses, we documented deep-sea food-web structure and trophic niches in Baltimore Canyon and the adjacent open slopes in the US Mid-Atlantic Region. Results revealed isotopically diverse feeding groups, comprising approximately 5 trophic levels. Regression analysis indicated that consumer isotope data are structured by habitat (canyon vs. slope), feeding group, and depth. Benthic feeders were enriched in 13 C and 15 N relative to suspension feeders, consistent with consuming older, more refractory organic matter. In contrast, canyon suspension feeders had the largest and more distinct isotopic niche, indicating they consume an isotopically discrete food source, possibly fresher organic material. The wider isotopic niche observed for canyon consumers indicated the presence of feeding specialists and generalists. High dispersion in δ 13 C values for canyon consumers suggests that the isotopic composition of particulate organic matter changes, which is linked to depositional dynamics, resulting in discrete zones of organic matter accumulation or resuspension. Heterogeneity in habitat and food availability likely enhances trophic diversity in canyons. Given their abundance in the world's oceans, our results from Baltimore Canyon suggest that submarine canyons may represent important havens for trophic diversity.

Baltimore Canyon↗
USGS2023

Survival of Common Loon chicks appears unaffected by Bald Eagle recovery in northern Minnesota

Recovering species are not returning to the same environments or communities from which they disappeared. Conservation researchers and practitioners are thus faced with additional challenges in ensuring species resilience in these rapidly changing ecosystems. Assessing the resilience of species in these novel systems can still be guided by species’ ecology, including knowledge of their population size, life history traits, and behavioral adaptations, as well as the type, strength, and number of ways that they interact with other species in the community. We summarized broad trends of Common Loons ( Gavia immer ) breeding at Voyageurs National Park from 1973 to 2009, and evaluated the effects of increased risk from recovering Bald Eagles ( Haliaeetus leucocephalus ) on chick survival from 2004 to 2006. Adult Common Loons appear to have increased over time. Using Bayesian survival models that accounted for imperfect detection of unmarked individuals, we determined that chick survival of Common Loons was high from year to year and was unrelated to predation risk from Bald Eagles because chicks in territories closer to active nests did not experience greater mortality than those farther away. We suggest that Common Loon chicks were unaffected by the recovery of this top predator during the three years of sampling. Previous research indicates that Bald Eagles and other predators are an important source of egg losses, but Common Loons can compensate by re-nesting. Despite current uncertainties from anthropogenic threats, knowledge of a species’ ecology remains instrumental in determining its resilience during recovery.

Minnesota↗
USGS2019

Natural resource condition assessment: Channel Islands National Park

The Natural Resource Condition Assessment (NRCA) Program aims to provide documentation about the current conditions of important Park natural resources through a spatially explicit, multidisciplinary synthesis of existing scientific data and knowledge. Findings from the NRCA will help Channel Islands National Park (CINP) managers to develop near-term management priorities. The central objectives of this assessment were to evaluate the current conditions and trends of key Park resources, identify important knowledge gaps, and determine key stressors and threats. Because a recent report provided an assessment of marine resources (Engle 2006), which constitute 50% of the park, this NRCA focused on terrestrial resources. For this NRCA, CINP resource managers identified that the greatest Park need was to know whether or not vegetation (primarily woody vegetation) is recovering on the Channel Islands and how this may be influencing recovery of the native terrestrial vertebrates. To address this, the CINP NRCA team evaluated the condition of island vegetation and vertebrate communities using both: 1) already available, summarized information from reports, theses, and journal articles and 2) new analyses of recently available, existing data collected on the islands. Descriptions of specific methods used to analyze available data by the NRCA team are provided within the assessment sections in Chapter 4 of this report. The Team used the Vital Signs indicators as identified by Fancy et al. (2009) for monitoring the condition of Natural Resources in U.S. National Parks. Using this framework, the focal study resource components were the five CINP islands, because these are the bio-geophysical resources of greatest interest to the CINP. Each of the islands has its own unique history of human impacts, ecological conditions, restoration efforts, and natural resource monitoring. The Team evaluated island scrub recovery by assessing changes over time in two metrics: 1) vegetation community structure (species composition, cover, and spatial extent), and 2) vertebrate abundance, relative to the reference condition of each island. The reference conditions for this NRCA were the particular island’s ecological state prior to European settlement or ranching, which represent the ecological state to which the NPS desires the park return. For each metric, the Team determined the Reference Conditions/Values, Current Condition, Trend, and Recovery Potential (based on a review of the literature and from the NRCA team’s analysis of newly available data), Threats and Stressors, Data Gaps, Overall Condition. A qualitative statement of overall current condition was created for each metric, after all data and literature relevant to the measures (i.e., vegetation and vertebrates) of each resource component (i.e., island) were reviewed and evaluated. All information gathered for this NRCA is available and managed by CINP, so that the compilation of resources would be available not only for the assessment team, but will be provided for future Park reference. Chapter 1 of this NRCA provides a descriptive background of NRCAs. Chapter 2 provides Park-wide natural resource background information, while Chapter 3 describes the overall methodological approach used in this assessment. Chapter 4 provides a detailed assessment of each island’s condition, which is then summarized Park-wide and for each island in Chapter 5. Based on both vegetation recovery and vertebrate population abundances, our assessment found Santa Cruz Island (SCI), Santa Rosa Island (SRI), San Miguel Island (SMI), and Anacapa Island (AI) to be, overall, in moderate condition and slowly recovering following the removal of non-native herbivores. The condition of Santa Barbara Island (SBI) is poor and remains in a state that is not likely to improve without assisted recovery by the Park. All islands have exhibited some level of native vegetation recovery, with most of the observed natural recovery occurring on SCI, SRI, SMI, and AI; very little recovery has occurred at present on SBI. Vegetation recovery is uneven across each island and largely limited to mesic areas, such as north-facing slopes. Areas that will likely require some assisted recovery efforts are those that are: at risk of erosion, isolated, lacking native seed banks, and plagued with high competition of non-native grasses and other invasives. Some plant communities, such as exposed upland vegetation on SRI, also have lower natural recovery potential and will likely require assisted recovery. The overall condition of the Park’s terrestrial island vertebrate species generally appears to be good and improving, with high potential for further recovery to reach pre-ranching era reference conditions. This is particularly true for vertebrates on SCI, SRI, and SMI. Although there are limited data for AI, the data that are available suggest that vertebrates on that island are in good condition and improving as well. However, the condition of SBI vertebrates is only moderate, with natural recovery potential being low, with many landbird species’ populations currently declining, extinct, or not improving. An overarching theme across the Park’s terrestrial island vertebrate populations is that many of them are in good condition because the particular animals are habitat generalists, so their population dynamics are not strongly tied to habitat conditions. However, those landbirds associated with riparian vegetation are not showing signs of recovery across the Park islands, and riparian areas appear to be one of the habitats with limited natural recovery potential on the islands. Overwhelmingly, the most critical data gap that emerged from our analysis was the lack of current vegetation maps for most of the islands (AI, SCI, SRI, SMI). The lack of this information made it difficult to assess spatial changes in island vegetation over time, and to relate those changes to observed changes in vertebrate species abundances. Therefore, we were limited in our spatial assessment of vegetation recovery for AI, SCI, SRI, and SMI, and were only able to relate the current vegetation with island landbird analysis for SBI. Another common theme across islands was the lack of information on best techniques for shrub reintroduction and recovery, and the success of invasive species removal and re-vegetation efforts. Abundance, distribution, and habitat affinities of reptiles and amphibians are poorly known for AI, SCI, SRI, and SMI, making it difficult to assess their population condition and trends, and their potential responses to shrub recovery. Mammal and landbird populations are reasonably well-sampled across most of the islands, but data are lacking for most vertebrates from AI, especially West and Middle AI where no vertebrate sampling occurs. The population status, cause of declines, and recovery needs are lacking for several landbird species across multiple islands, including loggerhead shrikes ( Lanius ludovicianus ssp.) on SCI and SRI, and Santa Cruz Island rufous crowned sparrows ( Aimophila ruficeps obscura ) on AI. Additionally, island song sparrows ( Melospiza melodia graminea ) remain extirpated on SBI and data are needed for assessing their recovery potential on the island. The potentially major threats facing the islands’ flora and fauna today are: areas of continued erosion, potential new non-native introductions, and climate change. The Park islands have already experienced warming over the last several decades due to human-induced climate change, and are projected to experience continued warming. These increasing stresses imposed by climate change may slow and inhibit natural recovery potentials for island fauna, and especially flora.

California↗
USGS2017

Mathematical models for plant-herbivore interactions

Mathematical Models of Plant-Herbivore Interactions addresses mathematical models in the study of practical questions in ecology, particularly factors that affect herbivory, including plant defense, herbivore natural enemies, and adaptive herbivory, as well as the effects of these on plant community dynamics. The result of extensive research on the use of mathematical modeling to investigate the effects of plant defenses on plant-herbivore dynamics, this book describes a toxin-determined functional response model (TDFRM) that helps explains field observations of these interactions. This book is intended for graduate students and researchers interested in mathematical biology and ecology.

Book↗
USGS2018

Generating community-built tools for data sharing and analysis in environmental networks

Rapid data growth in many environmental sectors has necessitated tools to manage and analyze these data. The development of tools often lags behind the proliferation of data, however, which may slow exploratory opportunities and scientific progress. The Global Lake Ecological Observatory Network (GLEON) collaborative model supports an efficient and comprehensive data–analysis–insight life cycle, including implementations of data quality control checks, statistical calculations/derivations, models, and data visualizations. These tools are community-built and openly shared. We discuss the network structure that enables tool development and a culture of sharing, leading to optimized output from limited resources. Specifically, data sharing and a flat collaborative structure encourage the development of tools that enable scientific insights from these data. Here we provide a cross-section of scientific advances derived from global-scale analyses in GLEON. We document enhancements to science capabilities made possible by the development of analytical tools and highlight opportunities to expand this framework to benefit other environmental networks.

Inland Waters↗
USGS2026

The Global Observation System for Mercury dataset for mercury stable isotope signatures in environmental media

The natural variability in the abundance ratios of stable isotopes of mercury (Hg), which collectively forms its isotopic composition, provides information on Hg sources and biogeochemical pathways. Modern mass spectrometry has allowed for measurement of Hg isotope ratios across atmospheric, aquatic, and terrestrial compartments, often at trace levels. Since realizing the utility of Hg isotope ratios, hundreds of studies have generated a wealth of data that is increasingly challenging to summarize and interpret for individual scientists. Arising as a complimentary initiative under the Global Observation System for Mercury (GOS 4 M) that supports the Minamata Convention on Mercury, we describe the establishment of the iGOS 4 M Hg isotope dataset. In its present form, iGOS 4 M has > 11,000 data entries from 190 studies, which together with metadata on sample type, geographical location, Hg concentration, and other environmental and ecological parameters, provide a long-needed catalogue of knowledge gathered by and for the Hg isotope community. We introduce the structure of iGOS 4 M and a standardization rubric to promote global consistency in measurement and data reporting.

Scientific Data↗
USGS2002

Fuzzy logic merger of spectral and ecological information for improved montane forest mapping.

Environmental data are often utilized to guide interpretation of spectral information based on context, however, these are also important in deriving vegetation maps themselves, especially where ecological information can be mapped spatially. A vegetation classification procedure is presented which combines a classification of spectral data from Landsat‐5 Thematic Mapper (TM) and environmental data based on topography and fire history. These data were combined utilizing fuzzy logic where assignment of each pixel to a single vegetation category was derived comparing the partial membership of each vegetation category within spectral and environmental classes. Partial membership was assigned from canopy cover for forest types measured from field sampling. Initial classification of spectral and ecological data produced map accuracies of less than 50% due to overlap between spectrally similar vegetation and limited spatial precision for predicting local vegetation types solely from the ecological information. Combination of environmental data through fuzzy logic increased overall mapping accuracy (70%) in coniferous forest communities of northwestern Montana, USA.

Montana↗
USGS2008

Mapping "old" versus "young" piñon-juniper stands with a predictive topo-climatic model in north-central New Mexico, USA

Piñon pine and juniper woodlands in the southwestern United States are often represented as an expanding and even invasive vegetation type, a legacy of historic grazing, and culpable in the degradation of western rangelands. A long-standing emphasis on forage production, in combination with recent hazard fuel concerns, has prompted a new era of woodland management with stated restoration objectives. Yet the extent and dynamics of piñon–juniper communities that predate intensive Euro-American settlement activities are poorly known or understood, while the intrinsic ecological, aesthetic, and economic values of old-growth woodlands are often overlooked. Historical changes in piñon–juniper stands include two related, but poorly differentiated processes: recent tree expansion into grass- or shrub-dominated (i.e., non-woodland) vegetation and thickening or infilling of savanna or mosaic woodlands predating settlement. Our work addresses the expansion pattern, modeling the occurrence of “older” savanna and woodland stands extant prior to 1850 in contrast to “younger” piñon–juniper growth of more recent, postsettlement origin. We present criteria in the form of a diagnostic key for distinguishing “older,” pre-Euro-American settlement piñon–juniper from “younger” (post-1850) stands and report results of predictive modeling and mapping efforts within a north-central New Mexico study area. Selected models suggest a primary role for soil moisture in the current distribution of “old” vs. “young” piñon–juniper stands. Presettlement era woodlands are shown to occupy a discrete ecological space, defined by the interaction of effective (seasonal) moisture with landform setting and fine-scale (soil/water) depositional patterns. “Older” stands are generally found at higher elevations or on skeletal soils in upland settings, while “younger” stands (often dominated by one-seed juniper, Juniperus monosperma ) are most common at lower elevations or in productive, depositional settings. Modeling at broad regional scales can enhance our general understanding of piñon–juniper ecology, while predictive mapping of local areas has potential to provide products useful for land management. Areas of the southwestern United States with strong monsoonal (summer moisture) patterns appear to have been the most susceptible to historical woodland expansion, but even here the great majority of extant piñon–juniper has presettlement origins (although widely thickened and infilled historically), and old-growth structure is not uncommon in appropriate upland settings.

Ecological Applications↗