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At least 19 recordsLinked to original sources
USGS2007

Climate-induced forest dieback as an emergent global phenomenon: Organized oral session at the Ecological Society of America/Society of Ecological Restoration Joint Meeting; San Jose, California, 5-10 August 2007

An organized oral session at the annual meeting of the Ecological Society of America in San Jose, Calif., posed this question: Is climate-induced drought stress triggering increasing rates and unusual patterns of forest die-off at a global scale? Twenty-nine researchers representing five continents reported on patterns, mechanisms, and projections of forest mortality. Observations include widespread forest dieback or reductions in tree cover and biodiversity in response to drought and warmer temperatures in the African Sahel (Patrick Gonzalez, The Nature Conservancy), Mediterranean and alpine Europe (Jorge Castro, Universidad de Granada), and Argentinean Patagonia (Thomas Kitzberger, Universidad Nacional del Comahue). In contrast, although much Eucalyptus mortality has resulted from recent droughts in Australia, warming trends have been less pronounced in the Southern Hemisphere and it is unclear if contemporary climate-induced tree mortality differs from previous historical drought impacts (Rod Fensham, Queensland Herbarium).

Eos, Transactions, American Geophysical Union↗
USGS2016

External influences on ecological theory: Report on organized oral Session 80 at the 100th Anniversary Meeting of the Ecological Society of America

The 100‐year history of the Ecological Society of America spans most of the major advances in the field of ecology, from the “niche” of Grinnell and others, to Lotka and Volterra's models of predation and competition based on the logistic growth equation, to the concept of competitive exclusion developed from experimental ecology, to genetics and evolutionary ecology and all the ramifications and specializations of these topics over the rest of the 20th and into the 21st century. The objective of this session, sponsored by the Historical Records Committee of the ESA, was to explore how ecological concepts have been shaped and changed by influences that are external to the scientific method, such as funding priorities, ideology, politics, personalities, and differences between the ecosystems where influential ecologists developed their ideas. Among the many memorable quotations of the philosopher/poet George Santayana (1863–1952) is the often quoted and misquoted observation, “Those who cannot remember the past are condemned to repeat it.”

Bulletin of the Ecological Society of America↗
USGS2017

Earth Stewardship: An initiative by the Ecological Society of America to foster engagement to sustain Planet Earth

The Ecological Society of America (ESA) has responded to the growing commitment among ecologists to make their science relevant to society through a series of concerted efforts, including the Sustainable Biosphere Initiative (1991), scientific assessment of ecosystem management (1996), ESA’s vision for the future (2003), Rapid Response Teams that respond to environmental crises (2005), and the Earth Stewardship Initiative (2009). During the past 25 years, ESA launched five new journals, largely reflecting the expansion of scholarship linking ecology with broader societal issues. The goal of the Earth Stewardship Initiative is to raise awareness and to explore ways for ecologists and other scientists to contribute more effectively to the sustainability of our planet. This has occurred through four approaches: (1) articulation of the stewardship concept in ESA publications and Website, (2) selection of meeting themes and symposia, (3) engagement of ESA sections in implementing the initiative, and (4) outreach beyond ecology through collaborations and demonstration projects. Collaborations include societies and groups of Earth and social scientists, practitioners and policy makers, religious and business leaders, federal agencies, and artists and writers. The Earth Stewardship Initiative is a work in progress, so next steps likely include continued nurturing of these emerging collaborations, advancing the development of sustainability and stewardship theory, improving communication of stewardship science, and identifying opportunities for scientists and civil society to take actions that move the Earth toward a more sustainable trajectory.

Book chapter↗
USGS2024

Tropical forests and global change: Biogeochemical responses and opportunities for cross-site comparisons, an organized INSPIRE session at the 108th Annual Meeting, Ecological Society of America, Portland, Oregon, USA, August 2023

Tropical forests play a critical role in the global carbon (C) cycle. These ecosystems maintain the highest rates of net primary production (NPP) on Earth (Hengl et al ., 2017 ), contain c . 30% of terrestrial C stocks (Jobbagy & Jackson, 2000 ), and have some of the largest stores of fine-root biomass globally (Jackson et al ., 1996 ), as well as higher fine-root production and turnover rates compared with other biomes (Cusack et al ., 2021 ). Tropical forest responses to projected warming, altered rainfall regimes, and elevated CO 2 concentrations (IPCC, 2021 ) are likely to be different from other ecosystems because of their unique characteristics (Box 1 ), making targeted research and model development important for understanding tropical forest–climate feedbacks. There is now a critical mass of long-term global change field experiments and modeling efforts in tropical forests, yet thus far there has been little synthesis, cross-site comparison, or multi-site standardized experimentation among tropical forests to help us understand how these biomes are changing. An organized INSPIRE session at the 108 th Annual Meeting of the Ecological Society of America set out to tackle just this. Speakers covered large-scale tropical forest field experiments and modeling efforts, with an emphasis on changes in ecosystem biogeochemistry under warming, drying, elevated atmospheric CO 2 , and changing nutrient status. In this Meeting report, we provide an overview of the large-scale global change experiments presented and highlight the main objectives and opportunities for tropical forest research that emerged, including cross-site comparisons and integration with ecosystem-scale models (Fig. 1 ).

New Phytologist↗
USGS2011

On thinning of chains in MCMC

1. Markov chain Monte Carlo (MCMC) is a simulation technique that has revolutionised the analysis of ecological data, allowing the fitting of complex models in a Bayesian framework. Since 2001, there have been nearly 200 papers using MCMC in publications of the Ecological Society of America and the British Ecological Society, including more than 75 in the journal Ecology and 35 in the Journal of Applied Ecology . 2. We have noted that many authors routinely 'thin' their simulations, discarding all but every k th sampled value; of the studies we surveyed with details on MCMC implementation, 40% reported thinning. 3. Thinning is often unnecessary and always inefficient, reducing the precision with which features of the Markov chain are summarised. The inefficiency of thinning MCMC output has been known since the early 1990's, long before MCMC appeared in ecological publications. 4. We discuss the background and prevalence of thinning, illustrate its consequences, discuss circumstances when it might be regarded as a reasonable option and recommend against routine thinning of chains unless necessitated by computer memory limitations.

Methods in Ecology and Evolution↗
USGS2008

The Importance of Uncertainty and Sensitivity Analysis in Process-based Models of Carbon and Nitrogen Cycling in Terrestrial Ecosystems with Particular Emphasis on Forest Ecosystems — Selected Papers from a Workshop Organized by the International Society for Ecological Modelling (ISEM) at the Third Biennal Meeting of the International Environmental Modelling and Software Society (IEMSS) in Burlington, Vermont, USA, August 9-13, 2006

Many process-based models of carbon (C) and nitrogen (N) cycles have been developed for terrestrial ecosystems, including forest ecosystems. They address many basic issues of ecosystems structure and functioning, such as the role of internal feedback in ecosystem dynamics. The critical factor in these phenomena is scale, as these processes operate at scales from the minute (e.g. particulate pollution impacts on trees and other organisms) to the global (e.g. climate change). Research efforts remain important to improve the capability of such models to better represent the dynamics of terrestrial ecosystems, including the C, nutrient, (e.g. N) and water cycles. Existing models are sufficiently well advanced to help decision makers develop sustainable management policies and planning of terrestrial ecosystems, as they make realistic predictions when used appropriately. However, decision makers must be aware of their limitations by having the opportunity to evaluate the uncertainty associated with process-based models ( Smith and Heath, 2001 and Allen et al., 2004 ). The variation in scale of issues currently being addressed by modelling efforts makes the evaluation of uncertainty a daunting task.

Ecological Modelling↗
USGS2021

A more representative community of ecologists

Ecologists play a crucial role in providing solutions to the challenges facing the world. For most of the history of the field, however, the science of ecology has been pursued by white men, and increasingly, by white women. This lack of diversity is untenable today, not only because it is socially unjust, but also because solving environmental problems requires diversity. Ecology as a science is an extremely rewarding and fun career choice for many, but how can the field recruit a more diverse workforce to do this important and gratifying work? Attracting and retaining future ecologists of color is the focus of this Forum. How do young people choose a career in ecology and environmental sciences? For many ecologists, environmental scientists and managers, and future natural resource professionals, an early field experience provides a crucial introduction and gateway. A sojourn at a field station, an extended field trip, or field expedition has introduced many of today’s professionals to their fields, but at the same time, a growing literature documents problematic behavior, discrimination, and other forms of harassment that have been far too frequently reported, and little attention has been given to conscious or implicit exclusion of students from diverse backgrounds. In their lead article, Bowser and Cid, two leading researchers and long-time champions of diversity in ecology, build on experience in long-running programs as well as the literature to diagnose challenges facing diverse youth, and present approaches to encourage, rather than discourage, further engagement. They describe affirmative and creative measures that foster a sense of inclusion and community among young scholars; this sense of belonging and empowerment allows many to advance to studies and careers in ecology and environmental science. In the subsequent six papers, authors explore topics either responding to, or inspired by, the lead paper. They explore alternatives to a field experience as a gateway to a career in ecology or environmental sciences through, for example, data science or the social sciences. Other comment papers describe challenges faced in the next phases of an academic career, barriers faced by specific cultural groups and the approaches, challenges, and outcomes of programs aiming to increase the diversity of the environmental STEM workforce. All responses sound a clarion call for change to hear and value different voices and perspectives to be heard and valued. These include (1) structural and cultural change to our institutions and reward structures; (2) developing and nurturing personal relationships among students and their mentors, within teams and in internships; (3) making entry to ecology inviting and making advancement in ecology free from systemic barriers; and (4) broadening our vision of ecology, and the ways we learn about the world’s ecosystems. The Ecological Society of America, the home for Ecological Applications , is committed to the diversity, equity and inclusion needed to tackle environmental challenges in unity (https://www.esa.org/esablog/2020/09/24/time-for-action-esa-initiates-a-diversity-equity-inclusion-and-justice-deij-task-force/). The world needs all available talent and perspectives to meet environmental challenges today. Ecological Applications has long published occasional papers on the profession of ecology and never ones more important or timely than these. The editorial team is proud to provide an outlet for the voices of our field, in all its current, if inadequate, diversity and honored to host the passionate and committed views of our authors.

Ecological Applications↗
USGS2014

The National Climate Change and Wildlife Science Center annual report for 2013

In 2008, Congress created the National Climate Change and Wildlife Science Center (NCCWSC) within the U.S. Geological Survey (USGS). The center was formed to respond to the demands of natural resource managers for rigorous scientific information and effective tools for assessing and responding to climate change. Located at the USGS National Headquarters in Reston, Va., the NCCWSC has invested more than $93 million (through FY13) in cutting-edge climate change research and, in response to Secretarial Order No. 3289, established and is managing eight regional Department of Interior (DOI) Climate Science Centers (CSCs). In 2013: The DOI CSCs awarded nearly $7 million in funding to universities and other partners for climate and land-use change research. The scientific work of the NCCWSC-CSC enterprise moved toward projects that focus on ‘Science Infrastructure and Capacity Building’ and ‘Thematic Science’. A permanent director, David Helweg, Ph.D., was hired for the Pacific Islands CSC (PI CSC), completing the CSC leadership team. Staff scientists were hired at the Alaska (AK), Northeast (NE), and Southeast (SE) CSCs. Each of the eight CSCs completed the formation of regional Stakeholder Advisory Committees (SACs) and a national advisory committee (ACCCNRS) was created to oversee the NCCWSC-CSC enterprise. NCCWSC staff worked on creating a searchable public database on climate change vulnerability assessments. NCCWSC scientists authored articles in a special issue of the Ecological Society of America’s journal Frontiers in Ecology and the Environment, which was devoted to an assessment of climate change effects on biodiversity and ecosystems, and the consequences for people. Learn more about these achievements in The National Climate Change and Wildlife Science Center Annual Report for 2013 .

Circular↗
USGS2007

On the choice of statistical models for estimating occurrence and extinction from animal surveys

In surveys of natural animal populations the number of animals that are present and available to be detected at a sample location is often low, resulting in few or no detections. Low detection frequencies are especially common in surveys of imperiled species; however, the choice of sampling method and protocol also may influence the size of the population that is vulnerable to detection. In these circumstances, probabilities of animal occurrence and extinction will generally be estimated more accurately if the models used in data analysis account for differences in abundance among sample locations and for the dependence between site-specific abundance and detection. Simulation experiments are used to illustrate conditions wherein these types of models can be expected to outperform alternative estimators of population site occupancy and extinction. ?? 2007 by the Ecological Society of America.

Ecology↗
USGS2011

Estimating equivalence with quantile regression

Equivalence testing and corresponding confidence interval estimates are used to provide more enlightened statistical statements about parameter estimates by relating them to intervals of effect sizes deemed to be of scientific or practical importance rather than just to an effect size of zero. Equivalence tests and confidence interval estimates are based on a null hypothesis that a parameter estimate is either outside (inequivalence hypothesis) or inside (equivalence hypothesis) an equivalence region, depending on the question of interest and assignment of risk. The former approach, often referred to as bioequivalence testing, is often used in regulatory settings because it reverses the burden of proof compared to a standard test of significance, following a precautionary principle for environmental protection. Unfortunately, many applications of equivalence testing focus on establishing average equivalence by estimating differences in means of distributions that do not have homogeneous variances. I discuss how to compare equivalence across quantiles of distributions using confidence intervals on quantile regression estimates that detect differences in heterogeneous distributions missed by focusing on means. I used one-tailed confidence intervals based on inequivalence hypotheses in a two-group treatment-control design for estimating bioequivalence of arsenic concentrations in soils at an old ammunition testing site and bioequivalence of vegetation biomass at a reclaimed mining site. Two-tailed confidence intervals based both on inequivalence and equivalence hypotheses were used to examine quantile equivalence for negligible trends over time for a continuous exponential model of amphibian abundance. ?? 2011 by the Ecological Society of America.

Ecological Applications↗
USGS2000

Diana H. Wall, ESA President 1999-2000

A more polite term for workaholic is over-achiever, and Diana Harrison Wall could easily serve as the type specimen for both words. Her ability to multi-task is a great boon for the Ecological Society of America. That characteristic drive has also been essential to Wall’s own personal success, since it pushed her to persevere during the lean years when a woman’s place was NOT in the field or laboratory. Diana is a very strong role model for young ecologists through her enthusiasm for science, her remarkable scientific achievements, and her leadership skills. In addition to advising her many graduate students, Diana-as-role-model has been featured in many news media, including PBS TV shows such as “Horizons” and “Discovery,” National Geographic magazine, and the New York Times. She is highlighted on the ESA Web site: “What Do Ecologists Do? Focus on Ecologists.”

Bulletin of the Ecological Society of America↗
USGS2016

Using science-policy integration to improve ecosystem science and inform decision-making: Lessons from U.S. LTERs

This Special Session took place on 12 August 2015 at the 100th Meeting of the Ecological Society of America in Baltimore, Maryland, and was conceived of and coordinated by the Science Policy Exchange. The Science Policy Exchange (SPE) is a boundary- spanning organization established to work at the interface of science and policy to confront pressing environmental challenges . SPE was created as a collaborative of six research institutions to increase the impact of science on environmental decisions. This session was organized by Marissa Weiss and co- organized by Pamela Templer, Kathleen Fallon Lambert, Jill Baron, Charles Driscoll, and David Foster. Along the theme of ESA ’ s Centennial meeting, the group of presenters represented collectively more than 100 years of experience in integration of science, policy, and outreach.

Bulletin of the Ecological Society of America↗
USGS2007

Can modeling improve estimation of desert tortoise population densities?

The federally listed desert tortoise (Gopherus agassizii) is currently monitored using distance sampling to estimate population densities. Distance sampling, as with many other techniques for estimating population density, assumes that it is possible to quantify the proportion of animals available to be counted in any census. Because desert tortoises spend much of their life in burrows, and the proportion of tortoises in burrows at any time can be extremely variable, this assumption is difficult to meet. This proportion of animals available to be counted is used as a correction factor (g0) in distance sampling and has been estimated from daily censuses of small populations of tortoises (6-12 individuals). These censuses are costly and produce imprecise estimates of g0 due to small sample sizes. We used data on tortoise activity from a large (N = 150) experimental population to model activity as a function of the biophysical attributes of the environment, but these models did not improve the precision of estimates from the focal populations. Thus, to evaluate how much of the variance in tortoise activity is apparently not predictable, we assessed whether activity on any particular day can predict activity on subsequent days with essentially identical environmental conditions. Tortoise activity was only weakly correlated on consecutive days, indicating that behavior was not repeatable or consistent among days with similar physical environments. ?? 2007 by the Ecological Society of America.

Ecological Applications↗
USGS2009

The numerical and functional responses of a granivorous rodent and the fate of Neotropical tree seeds

Despite their potential to provide mechanistic explanations of rates of seed dispersal and seed fate, the functional and numerical responses of seed predators have never been explicitly examined within this context. Therefore, we investigated the numerical response of a small-mammal seed predator, Heteromys desmarestianus, to disturbance-induced changes in food availability and evaluated the degree to which removal and fate of seeds of eight tree species in a lowland tropical forest in Belize were related to the functional response of H. desmarestianus to varying seed densities. Mark-recapture trapping was used to estimate abundance of H. desmarestianus in six 0.5-ha grids from July 2000 to September 2002. Fruit availability and seed fate were estimated in each grid, and two experiments nested within the grids were used to determine (1) the form of the functional response for nine levels of fruit density (2-32 fruits/m 2 ), (2) the removal rate and handling times, and (3) the total proportion of fruits removed. The total proportion of fruits removed was determined primarily by the numerical response of H. desmarestianus to fruit availability, while removal rates and the proportion of seeds eaten or cached were related primarily to the form of the functional response. However, the numerical and functional responses interacted; H. desmarestianus showed strong spatial and temporal numerical responses to total fruit availability, and their density relative to fruit availability resulted in variation in the form of the functional response. Types I, II, and III functional responses were observed, as were density-independent responses, and these responses varied both among and within fruit species. The highest proportions of fruits were eaten when the Type III functional response was detected, which was when fruit availability was high relative to H. desmarestianus population density. Numerous idiosyncratic influences on seed fate have been documented, but our results indicate that shifts in the numerical and functional responses of seed predators to seasonal and interannual variation in seed availability potentially provide a general mechanistic explanation for patterns of removal and fate for vertebrate-dispersed seeds. ?? 2009 by the Ecological Society of America.

Ecology↗
USGS2010

Tuning stochastic matrix models with hydrologic data to predict the population dynamics of a riverine fish

We developed stochastic matrix models to evaluate the effects of hydrologic alteration and variable mortality on the population dynamics of a lotie fish in a regulated river system. Models were applied to a representative lotic fish species, the flathead catfish (Pylodictis olivaris), for which two populations were examined: a native population from a regulated reach of the Coosa River (Alabama, USA) and an introduced population from an unregulated section of the Ocmulgee River (Georgia, USA). Size-classified matrix models were constructed for both populations, and residuals from catch-curve regressions were used as indices of year class strength (i.e., recruitment). A multiple regression model indicated that recruitment of flathead catfish in the Coosa River was positively related to the frequency of spring pulses between 283 and 566 m 3 /s. For the Ocmulgee River population, multiple regression models indicated that year class strength was negatively related to mean March discharge and positively related to June low flow. When the Coosa population was modeled to experience five consecutive years of favorable hydrologic conditions during a 50-year projection period, it exhibited a substantial spike in size and increased at an overall 0.2% annual rate. When modeled to experience five years of unfavorable hydrologic conditions, the Coosa population initially exhibited a decrease in size but later stabilized and increased at a 0.4% annual rate following the decline. When the Ocmulgee River population was modeled to experience five years of favorable conditions, it exhibited a substantial spike in size and increased at an overall 0.4% annual rate. After the Ocmulgee population experienced five years of unfavorable conditions, a sharp decline in population size was predicted. However, the population quickly recovered, with population size increasing at a 0.3% annual rate following the decline. In general, stochastic population growth in the Ocmulgee River was more erratic and variable than population growth in the Coosa River. We encourage ecologists to develop similar models for other lotic species, particularly in regulated river systems. Successful management of fish populations in regulated systems requires that we are able to predict how hydrology affects recruitment and will ultimately influence the population dynamics of fishes. ?? 2010 by the Ecological Society of America.

Ecological Applications↗
USGS2009

Modeling utilization distributions in space and time

W. Van Winkle defined the utilization distribution (UD) as a probability density that gives an animal's relative frequency of occurrence in a two-dimensional (x, y) plane. We extend Van Winkle's work by redefining the UD as the relative frequency distribution of an animal's occurrence in all four dimensions of space and time. We then describe a product kernel model estimation method, devising a novel kernel from the wrapped Cauchy distribution to handle circularly distributed temporal covariates, such as day of year. Using Monte Carlo simulations of animal movements in space and time, we assess estimator performance. Although not unbiased, the product kernel method yields models highly correlated (Pearson's r - 0.975) with true probabilities of occurrence and successfully captures temporal variations in density of occurrence. In an empirical example, we estimate the expected UD in three dimensions (x, y, and t) for animals belonging to each of two distinct bighorn sheep {Ovis canadensis) social groups in Glacier National Park, Montana, USA. Results show the method can yield ecologically informative models that successfully depict temporal variations in density of occurrence for a seasonally migratory species. Some implications of this new approach to UD modeling are discussed. ?? 2009 by the Ecological Society of America.

Ecology↗
USGS2010

Land-use controls on sources and processing of nitrate in small watersheds: Insights from dual isotopic analysis

Studies have repeatedly shown that agricultural and urban areas export considerably more nitrogen to streams than forested counterparts, yet it is difficult to identify and quantify nitrogen sources to streams due to complications associated with terrestrial and in-stream biogeochemical processes. In this study, we used the isotopic composition of nitrate (??15N-NO3- and ??18O- NO3-) in conjunction with a simple numerical model to examine the spatial and temporal variability of nitrate (NO3-) export across a land-use gradient and how agricultural and urban development affects net removal mechanisms. In an effort to isolate the effects of land use, we chose small headwater systems in close proximity to each other, limiting the variation in geology, surficial materials, and climate between sites. The ??15N and ??18Oof stream NO 3- varied significantly between urban, agricultural, and forested watersheds, indicating that nitrogen sources are the primary determinant of the ??15N-NO3-, while the ??18O-NO3- was found to reflect biogeochemical processes. The greatest NO3- concentrations corresponded with the highest stream ??15N-NO3- values due to the enriched nature of two dominant anthropogenic sources, septic and manure, within the urban and agricultural watersheds, respectively. On average, net removal of the available NO3- pool within urban and agricultural catchments was estimated at 45%. The variation in the estimated net removal of NO3- from developed watersheds was related to both drainage area and the availability of organic carbon. The determination of differentiated isotopic land-use signatures and dominant seasonal mechanisms illustrates the usefulness of this approach in examining the sources and processing of excess nitrogen within headwater catchments. ?? 2010 by the Ecological Society of America.

Ecological Applications↗