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At least 865 records · Page 48Linked to original sources
USGS2025

Using a BACI design to assess stream ecology and chemistry response after wildfire

Wildfires can have complex effects on aquatic communities, which can be either beneficial or adverse depending on the setting. In California, USA, the size, frequency, and severity of wildfires has greatly increased over the last few decades. Understanding the effects of fire on aquatic ecosystem health and human land use has become increasingly important in managing the interface of the natural and urban landscape. In this study, we used a before–after control–impact (BACI) study design to test for differences in bed sediment chemistry, water chemistry, benthic algal biomass, and benthic macroinvertebrate communities between burned and unburned (control) watersheds, pre- and post-fire, using data collected before and after California’s 2017 Atlas, Nuns, and Tubbs wildfires. We found a treatment effect (burned vs control) on water chemistry, sediment trace-metal concentrations, algae, and community structure of benthic macroinvertebrates, but we found no evidence of an interaction between time period (pre- vs post-fire) and treatment. Both the difference in environmental factors between our control and burned sample sites and the proximity and degree of wildfire burn severity may have contributed to the results of this BACI study. Our results also highlight the importance of including control sites when assessing the effects of discrete disturbances, such as wildfire, to avoid spurious conclusions of disturbance effects that may be attributable to innate ecological variability.

Freshwater Science↗
USGS2020

An overview of agent-based models in plant biology and ecology

Agent-based modeling (ABM) has become an established methodology in many areas of biology, ranging from the cellular to the ecological population and community levels. In plant science, two different scales have predominated in their use of ABM. One is the scale of populations and communities, through the modeling of collections of agents representing individual plants, interacting with each other and with the environment. The other is the scale of the individual plant, through the modeling, by functional-structural plant models (FSPMs), of agents representing plant building blocks, or metamers, to describe the development of plant architecture and functions within individual plants. The purpose of this review is to show key results and parallels in ABM for growth, mortality, carbon allocation, competition, and reproduction across the scales from the plant organ to populations and communities on a range of spatial scale to the whole landscape. Several areas of application of ABMs are reviewed, showing that some issues are addressed by both population-level ABMs and FSPMs. Continued increase in the relevance of ABM to environmental science and management will be helped by greater integration of ABMs across these two scales.

Annals of Botany↗
USGS2015

On theory in ecology: Another perspective

We agree with Marquet and colleagues ( 2014 ) that the balance between theory and data is an important one. However, their description of what constitutes good theory in ecology ignores the most important characteristic of successful theory—that it accurately and precisely describes the way the world works.

BioScience↗
USGS2005

Crossing the ultimate ecological barrier: Evidence for an 11,000-km-long non-stop flight from Alaska to New Zealand and Eastern Australia by Bar-tailed Godwits

Populations of the Bar-tailed Godwit ( Limosa lapponica ; Scolopacidae) embark on some of the longest migrations known among birds. The baueri race breeds in western Alaska and spends the nonbreeding season a hemisphere away in New Zealand and eastern Australia; the menzbieri race breeds in Siberia and migrates to western and northern Australia. Although the Siberian birds are known to follow the coast of Asia during both migrations, the southern pathway followed by the Alaska breeders has remained unknown. Two questions have particular ecological importance: (1) do Alaska godwits migrate directly across the Pacific, a distance of 11 000 km? and (2) are they capable of doing this in a single flight without stopping to rest or refuel? We explored six lines of evidence to answer these questions. The distribution of resightings of marked birds of the baueri and menzbieri races was significantly different between northward and southward flights with virtually no marked baueri resighted along the Asian mainland during southward migration. The timing of southward migration of the two races further indicates the absence of a coastal Asia route by baueri with peak passage of godwits in general occurring there a month prior to the departure of most birds from Alaska. The use of a direct route across the Pacific is also supported by significantly more records of godwits reported from within a direct migration corridor than elsewhere in Oceania, and during the September to November period than at other times of the year. The annual but rare occurrence of Hudsonian Godwits ( L. haemastica ) in New Zealand and the absence of their records along the Asian mainland also support a direct flight and are best explained by Hudsonian Godwits accompanying Bar-tailed Godwits from known communal staging areas in Alaska. Flight simulation models, extreme fat loads, and the apparent evolution of a wind-selected migration from Alaska further support a direct, nonstop flight.

The Condor↗
USGS2015

Thermal onset of cellular and endocrine stress responses correspond to ecological limits in brook trout, an iconic cold-water fish

Climate change is predicted to change the distribution and abundance of species, yet underlying physiological mechanisms are complex and methods for detecting populations at risk from rising temperature are poorly developed. There is increasing interest in using physiological mediators of the stress response as indicators of individual and population-level response to environmental stressors. Here, we use laboratory experiments to show that the temperature thresholds in brook trout ( Salvelinus fontinalis ) for increased gill heat shock protein-70 (20.7°C) and plasma glucose (21.2°C) are similar to their proposed thermal ecological limit of 21.0°C. Field assays demonstrated increased plasma glucose, cortisol and heat shock protein-70 concentrations at field sites where mean daily temperature exceeded 21.0°C. Furthermore, population densities of brook trout were lowest at field sites where temperatures were warm enough to induce a stress response, and a co-occurring species with a higher thermal tolerance showed no evidence of physiological stress at a warm site. The congruence of stress responses and proposed thermal limits supports the use of these thresholds in models of changes in trout distribution under climate change scenarios and suggests that the induction of the stress response by elevated temperature may play a key role in driving the distribution of species.

Conservation Physiology↗
USGS2025

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

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

Great Lakes–Upper St Lawrence River study area↗
USGS2026

Deconstructing cardiovascular and coagulation-related traits links dietary ecology to multi-functional snake venom specificity

Animal venoms vary greatly in compositional complexity, where complex venoms are hypothesized to be maintained by greater dietary breadth. Beyond explaining venom composition, the dietary breadth hypothesis predicts that these more complex venoms should show greater functional breadth in terms of overall toxicity and by disrupting multiple prey physiological processes. We evaluate these predictions with six distinct physiological assays of cardiac and blood clotting functions and compared the effects of venoms from snake species with a range of taxonomic dietary diversity levels. We compared the taxonomic dietary generalists Agkistrodon piscivorus and Sistrurus miliarius to taxa with varying taxonomic specialization, namely Ag. contortrix and Crotalus adamanteus , and Azemiops feae . Comparing fish thrombocyte and mammal platelet aggregation and fibrin clot formation, only species with broader diets disrupted both fish and mammal hemostatic function. Venom of Ag. piscivorus , a uniquely fish-eating species, was the most disruptive of zebrafish heart rate, thrombocyte activation, vascular permeability, and clotting after injury. Sistrurus miliarius was also highly toxic, whereas mammal-specialists’ venoms scarcely altered zebrafish physiology. Our results support the hypothesis that dietary breadth selects functionally complex venoms. Understanding venom gene evolution, snakebite symptoms, and searching for therapeutics in venom should be guided by evolutionary ecology.

Evolution↗
USGS2025

The story of the Penobscot River Ecology Mural: A 10-step process for scientists to create public art

Rivers are home to a wide variety of biota, including fishes, amphibians, reptiles, birds, freshwater mussels, aquatic insects, and microscopic organisms that fill unique niches to support broader ecosystem functions. While the general public may be aware of recreationally relevant biological life (e.g., fishes and insects to model flyfishing flies from), they may not be aware of more obscure yet important taxa. For example, freshwater mussels (Unionidae) improve water quality and clarity of rivers through filtration ( Vaughn, 2018), which is vital to riverine ecosystems. Despite this importance, lack of public knowledge about freshwater mussels is the second biggest challenge to their management ( Bouska et al., 2018). How do we best get the public to see value in underappreciated taxa to support their conservation? Public art installations can spread awareness about science effectively because they distill information for broader audiences, are eye-catching, and reach people through an emotional, aesthetic, and personal lens ( Thompson et al., 2023). While invertebrates are generally viewed by the public with fear and aversion ( Kellert, 1993) this can be ameliorated through interaction and learning, particularly for children ( Miller et al., 2025). Through cross-disciplinary collaboration between artists, scientists and the local community, we created the “Penobscot River Ecology Mural,” a scientifically informed artwork featuring underappreciated taxa like mussels and insects. In this article, we will elucidate the story of how we successfully made this piece through 10 steps, which provide a blueprint for future endeavors.

Maine↗
USGS2006

The importance of physiological ecology in conservation biology

Many of the threats to the persistence of populations of sensitive species have physiological or pathological mechanisms, and those mechanisms are best understood through the inherently integrative discipline of physiological ecology. The desert tortoise was listed under the Endangered Species Act largely due to a newly recognized upper respiratory disease thought to cause mortality in individuals and severe declines in populations. Numerous hypotheses about the threats to the persistence of desert tortoise populations involve acquisition of nutrients, and its connection to stress and disease. The nutritional wisdom hypothesis posits that animals should forage not for particular food items, but instead, for particular nutrients such as calcium and phosphorus used in building bones. The optimal foraging hypothesis suggests that, in circumstances of resource abundance, tortoises should forage as dietary specialists as a means of maximizing intake of resources. The optimal digestion hypothesis suggests that tortoises should process ingesta in ways that regulate assimilation rate. Finally, the cost-of-switching hypothesis suggests that herbivores, like the desert tortoise, should avoid switching food types to avoid negatively affecting the microbe community responsible for fermenting plants into energy and nutrients. Combining hypotheses into a resource acquisition theory leads to novel predictions that are generally supported by data presented here. Testing hypotheses, and synthesizing test results into a theory, provides a robust scientific alternative to the popular use of untested hypotheses and unanalyzed data to assert the needs of species. The scientific approach should focus on hypotheses concerning anthropogenic modifications of the environment that impact physiological processes ultimately important to population phenomena. We show how measurements of such impacts as nutrient starvation, can cause physiological stress, and that the endocrine mechanisms involved with stress can result in disease. Finally, our new syntheses evince a new hypothesis. Free molecules of the stress hormone corticosterone can inhibit immunity, and the abundance of "free corticosterone" in the blood (thought to be the active form of the hormone) is regulated when the corticosterone molecules combine with binding globulins. The sex hormone, testosterone, combines with the same binding globulin. High levels of testosterone, naturally occurring in the breeding season, may be further enhanced in populations at high densities, and the resulting excess testosterone may compete with binding globulins, thereby releasing corticosterone and reducing immunity to disease. This sequence could result in physiological and pathological phenomena leading to population cycles with a period that would be essentially impossible to observe in desert tortoise. Such cycles could obscure population fluctuations of anthropogenic origin. ?? 2006 The Author(s).

Conference Paper↗
USGS2025

Manipulation of the Symbiodiniaceae microbiome confers multigenerational impacts on symbioses and reproductive ecology of its Exaiptasia diaphana host

Symbiodiniaceae-associated microbiota strongly influence cnidarian symbioses. We systematically reduced the bacterial and fungal communities associated with Symbiodiniaceae to study potential effects on the cnidarian holobiont Exaiptasia diaphana (Aiptasia). Clonal anemones were inoculated with xenic Breviolum minutum (SSB01) and microbiome-manipulated cultures after antibacterial or antifungal treatment. The asexual reproduction of pedal laceration allowed for three generations of clonal aposymbiotic Aiptasia to be utilised in this study, from the initial adult generation (G0), to the first (G1), and second (G2) generation. We inoculated small and large G1 Aiptasia with SSB01 algae and monitored onset of symbiosis, rate of algal proliferation, and holobiont characteristics. Sequencing the 16S and 18S rRNA gene regions identified significant differences in the bacterial and fungal communities of the G0 and G1 generations, alongside differences between the size classes of small and large G1 anemones. The microbiome of larger G1 individuals was distinct to the smaller G1 anemones, suggesting a microbiome maturation process. Control Breviolum minutum cultures exhibited a significantly greater proliferation rate in large G1 anemones when compared to antibacterial or antifungal treated cultures, whereas the opposite trend was documented in the small G1 anemones. Although no differences were observed between algal photochemical parameters, or the growth and polyp activity of G1 juveniles, we observed a significant influence in the production of G2 clones between treatments. Overall, we provide strong ecological implications of manipulating Symbiodiniaceae microbiome, not for the algae themselves, but for the maturation of the host Aiptasia, as well as for the cnidarian holobiont over multiple generations.

The ISME Journal↗
USGS2008

Extreme endurance flights by landbirds crossing the Pacific Ocean: Ecological corridor rather than barrier?

Mountain ranges, deserts, ice fields and oceans generally act as barriers to the movement of land-dependent animals, often profoundly shaping migration routes. We used satellite telemetry to track the southward flights of bar-tailed godwits (Limosa lapponica baueri), shorebirds whose breeding and non-breeding areas are separated by the vast central Pacific Ocean. Seven females with surgically implanted transmitters flew non-stop 8117-11680km (10153??1043 s.d.) directly across the Pacific Ocean; two males with external transmitters flew non-stop along the same corridor for 7008-7390km. Flight duration ranged from 6.0 to 9.4 days (7.8??1.3 s.d.) for birds with implants and 5.0 to 6.6 days for birds with externally attached transmitters. These extraordinary non-stop flights establish new extremes for avian flight performance, have profound implications for understanding the physiological capabilities of vertebrates and how birds navigate, and challenge current physiological paradigms on topics such as sleep, dehydration and phenotypic flexibility. Predicted changes in climatic systems may affect survival rates if weather conditions at their departure hub or along the migration corridor should change. We propose that this transoceanic route may function as an ecological corridor rather than a barrier, providing a wind-assisted passage relatively free of pathogens and predators. ?? 2008 The Royal Society.

Proceedings of the Royal Society B: Biological Sci↗
USGS2010

Global positioning system and associated technologies in animal behaviour and ecological research

Biologists can equip animals with global positioning system (GPS) technology to obtain accurate (less than or equal to 30 m) locations that can be combined with sensor data to study animal behaviour and ecology. We provide the background of GPS techniques that have been used to gather data for wildlife studies. We review how GPS has been integrated into functional systems with data storage, data transfer, power supplies, packaging and sensor technologies to collect temperature, activity, proximity and mortality data from terrestrial species and birds. GPS 'rapid fixing' technologies combined with sensors provide location, dive frequency and duration profiles, and underwater acoustic information for the study of marine species. We examine how these rapid fixing technologies may be applied to terrestrial and avian applications. We discuss positional data quality and the capability for high-frequency sampling associated with GPS locations. We present alternatives for storing and retrieving data by using dataloggers (biologging), radio-frequency download systems (e.g. very high frequency, spread spectrum), integration of GPS with other satellite systems (e.g. Argos, Globalstar) and potential new data recovery technologies (e.g. network nodes). GPS is one component among many rapidly evolving technologies. Therefore, we recommend that users and suppliers interact to ensure the availability of appropriate equipment to meet animal research objectives.

Philosophical Transactions of the Royal Society B:↗
USGS2017

Lyme disease ecology in a changing world: Consensus, uncertainty and critical gaps for improving control

Lyme disease is the most common tick-borne disease in temperate regions of North America, Europe and Asia, and the number of reported cases has increased in many regions as landscapes have been altered. Although there has been extensive work on the ecology and epidemiology of this disease in both Europe and North America, substantial uncertainty exists about fundamental aspects that determine spatial and temporal variation in both disease risk and human incidence, which hamper effective and efficient prevention and control. Here we describe areas of consensus that can be built on, identify areas of uncertainty and outline research needed to fill these gaps to facilitate predictive models of disease risk and the development of novel disease control strategies. Key areas of uncertainty include: (i) the precise influence of deer abundance on tick abundance, (ii) how tick populations are regulated, (iii) assembly of host communities and tick-feeding patterns across different habitats, (iv) reservoir competence of host species, and (v) pathogenicity for humans of different genotypes of Borrelia burgdorferi . Filling these knowledge gaps will improve Lyme disease prevention and control and provide general insights into the drivers and dynamics of this emblematic multi-host–vector-borne zoonotic disease.

Philosophical Transactions of the Royal Society B:↗
USGS2021

The ecology and evolution of synchronized reproduction in long-lived plants

Populations of many long-lived plants exhibit spatially synchronized seed production that varies extensively over time, so that seed production in some years is much higher than on average, while in others, it is much lower or absent. This phenomenon termed masting or mast seeding has important consequences for plant reproductive success, ecosystem dynamics and plant–human interactions. Inspired by recent advances in the field, this special issue presents a series of articles that advance the current understanding of the ecology and evolution of masting. To provide a broad overview, we reflect on the state-of-the-art of masting research in terms of underlying proximate mechanisms, ontogeny, adaptations, phylogeny and applications to conservation. While the mechanistic drivers and fitness consequences of masting have received most attention, the evolutionary history, ontogenetic trajectory and applications to plant–human interactions are poorly understood. With increased availability of long-term datasets across broader geographical and taxonomic scales, as well as advances in molecular approaches, we expect that many mysteries of masting will be solved soon. The increased understanding of this global phenomenon will provide the foundation for predictive modelling of seed crops, which will improve our ability to manage forests and agricultural fruit and nut crops in the Anthropocene.

Philosophical Transactions of the Royal Society B:↗
USGS2010

Development of a decision support system for monitoring, reporting and forecasting ecological conditions of the Appalachian Trail

This paper introduces a collaborative multi-agency effort to develop an Appalachian Trail (A.T.) MEGA-Transect Decision Support System (DSS) for monitoring, reporting and forecasting ecological conditions of the A.T. and the surrounding lands. The project is to improve decisionmaking on management of the A.T. by providing a coherent framework for data integration, status reporting and trend analysis. The A.T. MEGA-Transect DSS is to integrate NASA multi-platform sensor data and modeling through the Terrestrial Observation and Prediction System (TOPS) and in situ measurements from A.T. MEGA-Transect partners to address identified natural resource priorities and improve resource management decisions.

Connecticut, Georgia, Maine, Maryland, Massachuset↗
USGS2019

Reduced soil macropores and forest cover reduce warm-season baseflow below ecological thresholds in the upper Delaware River Basin

We examined the impacts of changes in land cover and soil conditions on the flow regime of the upper Delaware River Basin using the Water Availability Tool for Environmental Resources (WATER). We simulated flows for two periods, circa 1600 and 1940, at three sites using the same temperature and precipitation conditions: the East Branch (EB), West Branch (WB), and mainstem Delaware River at Callicoon, NY. The 1600 period represented pristine forest and soils. The 1940 period included reduced forest cover, increased agriculture, and degraded soils with reduced soil macropore fractions. A model-sensitivity test examined the impact of soil macropore and land cover change separately. We assessed changes in flow regimes between the 1600 and 1940 periods using a variety of flow statistics, including established ecological limits of hydrologic alteration (ELOHA) thresholds. Reduced forest soil macropore fraction significantly reduced summer and fall base flows. The 1940 period had significantly lower Q50 flows (50% exceedance) than the 1600 period, as well as summer and fall Q90 and Q75-90 flows below the ELOHA thresholds. The 1- to 7-day minimum flows were also lower for the 1940 period, by 17% on the mainstem. 1940 flows were 6% more likely than the 1600 period to fall below the low-flow threshold for federally endangered dwarf wedgemussel (Alasmidonta heterodon) habitat. In contrast, the 1940 period had higher flows than the 1600 period from late fall to early winter.

New York, Pennsylvania↗
USGS2020

Application of a new species-richness based flow ecology framework for assessing flow reduction effects on aquatic communities

Water‐resources managers are challenged with maintaining a balance among beneficial uses throughout river networks and need robust means of assessing potential risks to aquatic life resulting from flow alterations. This study generated ecological limit functions from species‐streamflow relations to quantify potential fish richness response to flow alteration and compared results to currently accepted streamflow management guidelines. Modeled responses of absolute richness change were watershed specific and varied among sample sets derived from hydrologic unit classifications of different sizes (large HUC 6 basins to regional scale HUC 8). With a 20% flow reduction, 10% of HUC 8 predicted a richness decrease in one or more taxa. While absolute richness change was consistent across streams within a HUC, percent richness change was stream size dependent. Comparisons with Instream Flow Incremental Methodology habitat models predicted habitat loss greater than percent richness change; however, predictions for habitat and richness decreased similarly as stream size decreased. Watershed‐specific responses from flow reductions could allow water‐resources management decisions to be made locally based on the predicted richness change for certain sized streams. Quantitative results highlight the utility of a richness‐based framework for generating watershed‐specific risk assessments that validate and inform currently employed water‐resources management practices.

Virginia↗
USGS2023

Low-complexity floodplain inundation model performs well for ecological and management applications in a large river ecosystem

Flooding is a dominant physical process that drives the form and function of river-floodplain ecosystems. Efficiently characterizing flooding dynamics can be challenging, especially over geographically broad areas or at spatial and temporal scales relevant for ecosystem management activities. Here, we empirically evaluated a low-complexity geospatial model of floodplain inundation in six study segments of the Upper Mississippi River System (UMRS) by pairing spatially extensive, temporally limited and spatially limited, temporally extensive sampling designs. We found little evidence of systematic bias in model performance although discrepancies between model predictions and empirical data did occur locally. Assessments of model predictions revealed low segment-wide discrepancies of wetted extent under contrasting flow conditions and agreement for inundation event detection and duration. Model performance for predicting event frequency and duration was similar among sites expected to exhibit contrasting patterns of hydrologic connectivity with the main channel. Our results suggest that low-complexity models can efficiently characterize a critical physical process across geographically broad, complex river-floodplain ecosystems. Such tools have the potential for advancing scientific understanding of landscape-scale ecological patterns and for prioritizing management actions in large, complex river-floodplain ecosystems like the UMRS.

Illinois, Iowa, Minnesota, Missouri, Wisconsin↗