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At least 847 records · Page 47Linked to original sources
USGS2008

Modelling invasion for a habitat generalist and a specialist plant species

Predicting suitable habitat and the potential distribution of invasive species is a high priority for resource managers and systems ecologists. Most models are designed to identify habitat characteristics that define the ecological niche of a species with little consideration to individual species' traits. We tested five commonly used modelling methods on two invasive plant species, the habitat generalist Bromus tectorum and habitat specialist Tamarix chinensis, to compare model performances, evaluate predictability, and relate results to distribution traits associated with each species. Most of the tested models performed similarly for each species; however, the generalist species proved to be more difficult to predict than the specialist species. The highest area under the receiver-operating characteristic curve values with independent validation data sets of B. tectorum and T. chinensis was 0.503 and 0.885, respectively. Similarly, a confusion matrix for B. tectorum had the highest overall accuracy of 55%, while the overall accuracy for T. chinensis was 85%. Models for the generalist species had varying performances, poor evaluations, and inconsistent results. This may be a result of a generalist's capability to persist in a wide range of environmental conditions that are not easily defined by the data, independent variables or model design. Models for the specialist species had consistently strong performances, high evaluations, and similar results among different model applications. This is likely a consequence of the specialist's requirement for explicit environmental resources and ecological barriers that are easily defined by predictive models. Although defining new invaders as generalist or specialist species can be challenging, model performances and evaluations may provide valuable information on a species' potential invasiveness.

Diversity and Distributions↗
USGS2020

Context-dependent effects of livestock grazing in deserts of western North America

This chapter provides a general review of grazing disturbance by large mammalian grazers and the role of ecological context in moderating its effects, with emphasis on North American deserts. It discusses the ecological consequences of cessation of livestock grazing and present a case study from the Mojave Desert, United States of America. A primary effect of grazing is selective removal and ingestion of herbaceous plants, in contrast to removal of woody biomass from woody plants by browsing herbivores. The consequences of grazing–and resilience of a system to grazing disturbance–are highly context-dependent and vary across rangelands globally. Synergistic interactions between soil depth and plant structural properties, such as rooting depth and water-use efficiency, also influence plant access to water, and therefore moderate plant responses to drought and resilience to grazing. In some ecosystems, livestock grazing constitutes a novel or intensified disturbance. Application of the Intermediate Disturbance Hypothesis to grazing disturbance has been relatively infrequently tested relative to other ecological disturbances.

California, Nevada↗
USGS2000

Microsatellites: Evolutionary and methodological background and empirical applications at individual, population, and phylogenetic levels

The recent proliferation and greater accessibility of molecular genetic markers has led to a growing appreciation of the ecological and evolutionary inferences that can be drawn from molecular characterizations of individuals and populations (Burke et al. 1992, Avise 1994). Different techniques have the ability to target DNA sequences which have different patterns of inheritance, different modes and rates of evolution and, concomitantly, different levels of variation. In the quest for 'the right marker for the right job', microsatellites have been widely embraced as the marker of choice for many empirical genetic studies. The proliferation of microsatellite loci for various species and the voluminous literature compiled in very few years associated with their evolution and use in various research applications, exemplifies their growing importance as a research tool in the biological sciences. The ability to define allelic states based on variation at the nucleotide level has afforded unparalleled opportunities to document the actual mutational process and rates of evolution at individual microsatellite loci. The scrutiny to which these loci have been subjected has resulted in data that raise issues pertaining to assumptions formerly stated, but largely untestable for other marker classes. Indeed this is an active arena for theoretical and empirical work. Given the extensive and ever-increasing literature on various statistical methodologies and cautionary notes regarding the uses of microsatellites, some consideration should be given to the unique characteristics of these loci when determining how and under what conditions they can be employed.

Book chapter↗
USGS2018

Lower lethal temperatures for nonnative freshwater fishes in Everglades National Park, Florida

Temperature is an important factor that shapes biogeography and species composition. In southern Florida, the tolerance of nonnative freshwater fishes to low temperatures is a critical factor in delineating their geographic spread. In this study, we provide empirical information on experimentally derived low-temperature tolerance limits of Banded Cichlid Heros severus and Spotfin Spiny Eel Macrognathus siamensis, two nonnative Everglades fishes that were lacking data, and African Jewelfish Hemichromis letourneuxi and Mayan Cichlid Cichlasoma urophthalmus, species for which previous results were derived from studies with small sample sizes. We also provide a literature review summarizing the current state of knowledge of low-temperature tolerances for all 17 nonnative freshwater fishes that have been found in Everglades National Park. Mean lower lethal temperature tolerances ranged from 4°C (Orinoco Sailfin Catfish Pterygoplichthys multiradiatus) to 16.1°C (Butterfly Peacock Bass Cichla ocellaris). These low-temperature limits may inform the understanding of the ecological role or influence of nonnative fishes and may lead to potential management opportunities and applications.

Florida↗
USGS1987

A model of the productivity of the mallard duck

This paper describes a stochastic computer model that simulates recruitment of the mallard ( Anas platyrhynchos ) under different habitat conditions and management scenarios. The model incorporates several environmental phenomena and biological relations that affect mallard recruitment. Major events include arrival of mallards in the spring, daily survival of hens, initiation of nests, selection of nest sites, survival of nests until hatching, and survival of broods until fledging. The model was originally developed as a tool for synthesizing the results of research. Subsequently, we applied the model to a variety of management situations. We also describe the sources of estimates used in the model, evaluate its sensitivity to input parameters, and review some practical applications.

Ecological Modelling↗
USGS2015

The role of benefit transfer in ecosystem service valuation

The demand for timely monetary estimates of the economic value of nonmarket ecosystem goods and services has steadily increased over the last few decades. This article describes the use of benefit transfer to generate monetary value estimates of ecosystem services specifically. The article provides guidance for conducting such benefit transfers and summarizes advancements in benefit transfer methods, databases and analysis tools designed to facilitate its application.

Ecological Economics↗
USGS2004

Gulf of Mexico Integrated Science - Tampa Bay Study - Data Information Management System (DIMS)

The Tampa Bay Integrated Science Study is an effort by the U.S. Geological Survey (USGS) that combines the expertise of federal, state and local partners to address some of the most pressing ecological problems of the Tampa Bay estuary. This project serves as a template for the application of integrated research projects in other estuaries in the Gulf of Mexico. Efficient information and data distribution for the Tampa Bay Study has required the development of a Data Information Management System (DIMS). This information system is being used as an outreach management tool, providing information to scientists, decision makers and the public on the coastal resources of the Gulf of Mexico.

Open-File Report↗
USGS2020

FLOwPER user guide—For collection of FLOw PERmanence field observations

The accurate mapping of streams and their streamflow conditions in terms of presence or absence of surface water is important to both understanding physical, chemical, and biological processes in streams and to managing land, water, and ecological resources. This document describes a field form, FLOwPER (FLOw PERmanence), available within a mobile application (app), for standardized data collection of the presence or absence of surface flow in streams. The FLOwPER Database is a publicly available geodataset that can be used for research and management applications. This document provides instructions on how to (1) access and download the FLOwPER field form within the mobile app service, (2) use and complete a FLOwPER field form, and (3) view and download data from the FLOwPER Database.

Open-File Report↗
USGS1990

Methods of measurement of exploratory well impacts, offshore Florida

Six offshore oil well tests were drilled off Key West in the late 1950s and early 1960s. Two wells were drilled on coral bottom, two on carbonate sand, and two on mixed turtle grass and gorgonian/sponge hardbottom. After locating the sites with a proton magnetometer; several underwater assessment methods were used to measure the ecological impacts of drilling. Because of differing environments and bottom types, no single method was applicable at every site.

Florida↗
USGS2026

How Indigenous socio-cultural systems resist, accept, or direct ecological transformation: A research agenda

Anthropogenic ecological transformations are challenging conventional environmental management paradigms, as maintaining historical ecological structures and functions becomes increasingly untenable. The resist–accept–direct (RAD) framework offers a strategic tool to navigate these shifts. However, as a product of the dominant socio-cultural system, the RAD framework risks perpetuating the same patterns of thinking that have contributed to unsustainable social-ecological dynamics. Indigenous socio-cultural systems, considered here through the lens of long-term coevolution with their environments, offer valuable empirical models for adaptive responses to environmental change. Such Indigenous socio-cultural responses, grounded in narratives, governance institutions, value systems, and other cultural elements collectively referred to as Indigenous Knowledge (IK), hold relevance for addressing today’s intertwined environmental and social challenges. We provide a targeted review of existing literature at the intersection of IK and the RAD framework, along with a broader conceptual overview of relevant insights across related fields. These reveal contrasting assumptions about Indigenous responses to environmental change, such as consistently resisting to preserve cultural fidelity or uniformly accepting, reflecting deeper cultural, temporal, and ecological complexity. We propose a structured research agenda to investigate Indigenous socio-cultural responses to environmental change through empirical research, theoretical synthesis, hypothesis development, and practical application. This agenda is grounded in comprehensive collaboration, emphasizing shared power and integrating both emic and etic perspectives throughout all stages of research and implementation. By bridging the adaptive dynamics of coevolved social-ecological systems and mainstream management strategies, an IK–RAD framework could enhance the efficacy of responses to global environmental change.

Human Ecology↗
USGS2013

Spatial heterogeneity in statistical power to detect changes in lake area in Alaskan National Wildlife Refuges

Over the past 50 years, the number and size of high-latitude lakes have decreased throughout many regions; however, individual lake trends have been variable in direction and magnitude. This spatial heterogeneity in lake change makes statistical detection of temporal trends challenging, particularly in small analysis areas where weak trends are difficult to separate from inter- and intra-annual variability. Factors affecting trend detection include inherent variability, trend magnitude, and sample size. In this paper, we investigated how the statistical power to detect average linear trends in lake size of 0.5, 1.0 and 2.0 %/year was affected by the size of the analysis area and the number of years of monitoring in National Wildlife Refuges in Alaska. We estimated power for large (930–4,560 sq km) study areas within refuges and for 2.6, 12.9, and 25.9 sq km cells nested within study areas over temporal extents of 4–50 years. We found that: (1) trends in study areas could be detected within 5–15 years, (2) trends smaller than 2.0 %/year would take >50 years to detect in cells within study areas, and (3) there was substantial spatial variation in the time required to detect change among cells. Power was particularly low in the smallest cells which typically had the fewest lakes. Because small but ecologically meaningful trends may take decades to detect, early establishment of long-term monitoring will enhance power to detect change. Our results have broad applicability and our method is useful for any study involving change detection among variable spatial and temporal extents.

Alaska↗
USGS2007

Development of the Hydroecological Integrity Assessment Process for Determining Environmental Flows for New Jersey Streams

The natural flow regime paradigm and parallel stream ecological concepts and theories have established the benefits of maintaining or restoring the full range of natural hydrologic variation for physiochemical processes, biodiversity, and the evolutionary potential of aquatic and riparian communities. A synthesis of recent advances in hydroecological research coupled with stream classification has resulted in a new process to determine environmental flows and assess hydrologic alteration. This process has national and international applicability. It allows classification of streams into hydrologic stream classes and identification of a set of non-redundant and ecologically relevant hydrologic indices for 10 critical sub-components of flow. Three computer programs have been developed for implementing the Hydroecological Integrity Assessment Process (HIP): (1) the Hydrologic Indices Tool (HIT), which calculates 171 ecologically relevant hydrologic indices on the basis of daily-flow and peak-flow stream-gage data; (2) the New Jersey Hydrologic Assessment Tool (NJHAT), which can be used to establish a hydrologic baseline period, provide options for setting baseline environmental-flow standards, and compare past and proposed streamflow alterations; and (3) the New Jersey Stream Classification Tool (NJSCT), designed for placing unclassified streams into pre-defined stream classes. Biological and multivariate response models including principal-component, cluster, and discriminant-function analyses aided in the development of software and implementation of the HIP for New Jersey. A pilot effort is currently underway by the New Jersey Department of Environmental Protection in which the HIP is being used to evaluate the effects of past and proposed surface-water use, ground-water extraction, and land-use changes on stream ecosystems while determining the most effective way to integrate the process into ongoing regulatory programs. Ultimately, this scientifically defensible process will help to quantify the effects of anthropogenic changes and development on hydrologic variability and help planners and resource managers balance current and future water requirements with ecological needs.

Scientific Investigations Report↗
USGS2025

Spatial regimes provide ample early warning of tipping points

Accelerating global change is a hallmark of the Anthropocene, and the interaction of rapid change in climate, land use and land cover makes understanding the response of social-ecological systems to global change difficult to predict. Global change directly and indirectly affects both social-ecological systems and the landscapes in which they are embedded. Spatial heterogeneity in the location, manifestation of, and responses to global change makes spatially explicit approaches to management and conservation necessary. Spatial regimes, a concept derived from resilience theory, are at the forefront of attempts to operationalize and quantify resilience of dynamic landscapes. Spatial regimes are defined as dynamic landscape units that are shaped by a self-organizing set of processes and structures. They have identifiable spatial extents with discrete boundaries at a given scale that exhibit relative homogeneity in process, structure and composition maintained by feedback mechanisms. Here, we describe the concept of, evidence for, and applications of spatial regimes and how spatial regimes relate to scale and telecoupling of change across social-ecological systems. We emphasize the utility of the concept as an early warning of regime change, one that can provide ample early warning. We discuss methods that can be used to detect spatial regimes and uses of the concept for understanding and managing the spatio-temporal response of social-ecological systems to global change.

Advances in Ecological Research↗
USGS2026

Solar energy development selectively filters avian taxonomic and functional diversity across a perennial agricultural landscape

Solar energy is rapidly expanding across agricultural landscapes, yet its consequences for avian communities remain poorly understood, particularly among heterogeneous land-use matrices. In 2024 and 2025, we surveyed birds across 107 sites in New York State, including conventional solar arrays with mowing or sheep grazing to manage vegetation, solar-adjacent working lands (e.g. hayfields, pastures) and reference working lands independently located from solar arrays. We integrated diversity metrics across four trait dimensions—taxonomic, morphological, ecological and conservation status—and examined interactions between species-level abundance and traits to understand avian community responses to solar energy development. Avian species in solar sites tended to be common, non-migratory (in behaviour and wing morphology) and associated with shrubland or forest. Compared to reference working lands, bird communities in solar and solar-adjacent sites were less taxonomically diverse and were composed of fewer declining and range-restricted species. However, solar and solar-adjacent sites retained comparable diversity of intrinsic traits, suggesting that ecological function may persist despite apparent species filtering and functional reshuffling. While solar energy development can support avian communities with unique functional signatures, our findings suggest that conventional solar arrays sited on agricultural working lands in New York maintain low bird diversity and are unlikely to support conservation-priority species—such as grassland birds characterized by declining populations, migratory tendencies and open-habitat dependence. Synthesis and applications . Our study provides a pathway to leverage functional diversity to quantitatively characterize solar-associated avian communities and the ecological mechanisms that shape them. Our results suggest that meeting biodiversity conservation goals while achieving solar energy targets requires ecologically informed siting and processes, particularly across regions in which co-prioritization of conservation, agriculture and energy presents sustainability trade-offs.

New York↗
USGS2019

Drift of larval darters (Family Percidae) in the upper Roanoke River basin, USA, characterized using phenotypic and DNA barcoding markers

Larval fish ecology is poorly characterized because sampling is difficult and tools for phenotypically identifying larvae are poorly developed. While DNA barcoding can help address the latter problem, ‘universal’ primers do not work for all fish species. The Roanoke River in the southeastern United States includes seven darters (Family Percide: Tribe Etheostomatini). We made 393 collections of larval fishes in 2015 and 2018, examined darter larvae for morphometric and pigmentation traits, developed PCR primers amplifying darter DNA, and evaluated three gear types for collecting larval darters. Amplified DNA sequences for 1351 larvae matched archived mitochondrial cytochrome oxidase I sequences for darters occurring in the ecosystem. Larval darters were classified to genus with 100% accuracy using the ratio of pectoral fin length to body length; however, identification to species using morphometrics alone was subject to a misclassification rate of 11.8%, which can be resolved by considering pigmentation patterns. Gear-types varied considerably in their capture efficacy for larval darters; most Percina larvae were collected in drift nets. Larval Percina species appeared in the drift before Etheostoma species in both study years. Application of molecular genetic and phenotypic tools to larval fish identification can advance understanding of larval darter ecology.

North Carolina, Virginia↗
USGS2007

Developing methods to assess and predict the population and community level effects of environmental contaminants

The field of ecological toxicity seems largely to have drifted away from what its title implies—assessing and predicting the ecological consequences of environmental contaminants—moving instead toward an emphasis on individual effects and physiologic case studies. This paper elucidates how a relatively new ecological methodology, interaction assessment (INTASS), could be useful in addressing the field's initial goals. Specifically, INTASS is a model platform and methodology, applicable across a broad array of taxa and habitat types, that can be used to construct population dynamics models from field data. Information on environmental contaminants and multiple stressors can be incorporated into these models in a form that bypasses the problems inherent in assessing uptake, chemical interactions in the environment, and synergistic effects in the organism. INTASS can, therefore, be used to evaluate the effects of contaminants and other stressors at the population level and to predict how changes in stressor levels or composition of contaminant mixtures, as well as various mitigation measures, might affect population dynamics.

Integrated Environmental Assessment and Management↗
USGS2017

Multinomial N-mixture models improve the applicability of electrofishing for developing population estimates of stream-dwelling Smallmouth Bass

Failure to account for variable detection across survey conditions constrains progressive stream ecology and can lead to erroneous stream fish management and conservation decisions. In addition to variable detection’s confounding long-term stream fish population trends, reliable abundance estimates across a wide range of survey conditions are fundamental to establishing species–environment relationships. Despite major advancements in accounting for variable detection when surveying animal populations, these approaches remain largely ignored by stream fish scientists, and CPUE remains the most common metric used by researchers and managers. One notable advancement for addressing the challenges of variable detection is the multinomial N -mixture model. Multinomial N -mixture models use a flexible hierarchical framework to model the detection process across sites as a function of covariates; they also accommodate common fisheries survey methods, such as removal and capture–recapture. Effective monitoring of stream-dwelling Smallmouth Bass Micropterus dolomieu populations has long been challenging; therefore, our objective was to examine the use of multinomial N -mixture models to improve the applicability of electrofishing for estimating absolute abundance. We sampled Smallmouth Bass populations by using tow-barge electrofishing across a range of environmental conditions in streams of the Ozark Highlands ecoregion. Using an information-theoretic approach, we identified effort, water clarity, wetted channel width, and water depth as covariates that were related to variable Smallmouth Bass electrofishing detection. Smallmouth Bass abundance estimates derived from our top model consistently agreed with baseline estimates obtained via snorkel surveys. Additionally, confidence intervals from the multinomial N -mixture models were consistently more precise than those of unbiased Petersen capture–recapture estimates due to the dependency among data sets in the hierarchical framework. We demonstrate the application of this contemporary population estimation method to address a longstanding stream fish management issue. We also detail the advantages and trade-offs of hierarchical population estimation methods relative to CPUE and estimation methods that model each site separately.

Missouri, Oklahoma↗
USGS2020

Evaluating contributions of recent tracking-based animal movement ecology to conservation management

The use of animal-born sensors for location-based tracking and bio-logging in terrestrial systems has expanded dramatically in the past 10 years. This rapid expansion has generated new data on how animals interact with and respond to variation in their environment, resulting in important ecological, physiological, and evolutionary insights. Although understanding the finer details of animal locations has important management relevance, applied studies are not prominent in the movement ecology literature. This is despite the long history of applied studies of animal movement and the urgent and growing need for evidence-based conservation guidance, especially in the challenging field of human-wildlife interactions. The goal of this review is to evaluate the realized contribution of tracking-based animal movement ecology to solving specific conservation problems, and to identify barriers that may hinder expansion of that contribution. To do this, we (a) briefly review the history and technologies used in animal tracking and bio-logging, (b) use a series of literature searches to evaluate the frequency with which movement ecology studies are designed to solve specific conservation problems, and (c) use this information to identify challenges that may limit the applied relevance of the field of movement ecology, and to propose pathways to expand that applied relevance. Our literature review quantifies the limited extent to which research in the field of movement ecology is designed to solve specific conservation problems, but also the fact that such studies are slowly becoming more prevalent. We discuss how barriers that limit application of these principles are likely due to constraints imposed by the types of data used commonly in the field. Problems of scale mismatch, error compounding, and data paucity all create challenges that are relevant to the field of movement ecology but may be especially pertinent in applied situations. Finding solutions to these problems will create new opportunity for movement ecologists to contribute to conservation science.

Frontiers in Ecology and Evolution↗