Comparing freshwater mussel responses to stress using life-history and Dynamic Energy Budget theory.

Freshwater mussels are experiencing severe population declines, affecting their critical role in freshwater ecosystems. A thorough assessment of threats posed by various stressors is needed; however, the large number of species to be considered and significant data gaps, especially for listed species, hinder the process. We combined a traits-based approach to represent multiple species grouped into three life-history categories - Equilibrium, Opportunistic, and Periodic - with the Dynamic Energy Budget modeling principles to capture the physiological mechanisms driving individual-level responses.

Where have all the flowers gone? A systematic evaluation of factors driving native terrestrial plant decline in North America.

Prior to the arrival of Europeans in North America, forest and grasslands individually covered a 3rd of the conterminous United States; however, following the colonial and pioneer periods, respectively, these land cover categories were reduced to 70% and 50% of their original prominence. The dominant driving force for native land conversion was agriculture, which expanded exponentially from the Atlantic to the Pacific, comprising over half the total land area of America at its peak in 1950. However, farmland area has subsequently declined by 25%, so what has been driving native plant declines north of the 30th latitudinal parallel over the past 75 years? Analysis of recovery plans issued by the U.

Evaluating the perceptions of pesticide use, safety, and regulation and identifying common pesticide-related topics on Twitter.

Synthetic pesticides are important agricultural tools that increase crop yield and help feed the world's growing population. These products are also highly regulated to balance benefits and potential environmental and human risks. Public perception of pesticide use, safety, and regulation is an important topic necessitating discussion across a variety of stakeholders from lay consumers to regulatory agencies since attitudes toward this subject could differ markedly.

Development of a mechanistic model for analyzing avian reproduction data for pesticide risk assessment.

Mechanistic effect models are increasingly recommended as tools for refining evaluations of risk from exposure to pesticides. In the context of bird and mammal risk assessments, DEB-TKTD models have been recommended for characterizing sublethal effects at lower tiers. However, there are currently no such models.

Challenges with the current methodology for conducting Endangered Species Act risk assessments for pesticides in the United States.

The US Environmental Protection Agency (USEPA or the Agency) is responsible for administering the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The Agency is also required to assess the potential risks of pesticides undergoing registration or re-registration to threatened and endangered (i.e.

Atrazine and estradiol effects on development of Acris blanchardi (Blanchard's cricket frog) exposed in outdoor enclosures.

Background: The herbicide atrazine has been proposed as a potential endocrine disrupting compound (EDC) for amphibians. Using atrazine concentrations below or at those typically found in surface waters (0.5, 5.

Human induced fish declines in North America, how do agricultural pesticides compare to other drivers?

Numerous anthropogenic factors, historical and contemporary, have contributed to declines in the abundance and diversity of freshwater fishes in North America. When Europeans first set foot on this continent some five hundred years ago, the environment was ineradicably changed. Settlers brought with them diseases, animals, and plants via the Columbian Exchange, from the old world to the new, facilitating a process of biological globalization.

Development of a US national-scale, mixed-source, pesticide, rural well database for use in drinking water risk assessment: an atrazine case study.

For pesticide registrations in the USA under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as implemented by the United States Environmental Protection Agency, drinking water risk assessments for groundwater sources are based on standard scenario modeling concentration estimates. The conceptual model for the drinking water protection goals is defined in terms of (1) a rural well in or near a relatively high pesticide use area, a shallow well (4-10 m); (2) long-term, single-station weather data; (3) soils characterized as highly leachable; (4) upper-end or surrogate, worst-case environmental fate parameters; and (5) maximum, annual use rates repeated every year. To date, monitoring data have not been quantitatively incorporated into FIFRA drinking water risk assessment; even though considerable, US national-scale temporal and spatial data for some chemistries exists.

Characterization of field-scale spray drift deposition and non-target plant biological sensitivity: a corn herbicide (mesotrione/s-metolochlor) case study.

Background: This work reports a combined, field-scale spray drift deposition and plant bioassay study for a pre-mixture of the herbicides mesotrione and s-metolachlor. Wind direction data and field dimensions were used to evaluate the potential for spray drift to bypass downwind sampling devices. Variability in resulting spray drift across downwind distances was assessed alongside wind speed measured at on-site weather stations.

Using life-history trait variation to inform ecological risk assessments for threatened and endangered plant species.

Developing population models for assessing risks to terrestrial plant species listed as threatened or endangered under the Endangered Species Act (ESA) is challenging given a paucity of data on their life histories. The purpose of this study was to develop a novel approach for identifying relatively data-rich nonlisted species that could serve as representatives for species listed under the ESA in the development of population models to inform risk assessments. We used the USDA PLANTS Database, which provides data on plants present in the US territories, to create a list of herbaceous plants.

Coupling field-scale and watershed models for regulatory modeling of pesticide aquatic exposures in streams.

Estimating exposure in receiving waterbodies is a key step in the regulatory process to evaluate potential ecological risks posed by the use of agricultural pesticides. The United States Environmental Protection Agency (USEPA) currently uses the Variable Volume Water Model (VVWM) to predict environmental concentrations of pesticides in static waterbodies (ponds) that receive edge-of-field runoff inputs from the Pesticide Root Zone Model (PRZM). This regulatory model, however, does not adequately characterize potential pesticide concentrations in flowing water systems (streams and rivers) drained from watershed areas.

A data accuracy evaluation strategy to improve the representation of potential pesticide use areas for endangered species assessments.

The use of "best available data" is a fundamental requirement for all scientific forms of analysis. This paper discusses ways to improve the accuracy of data used to evaluate the potential impacts of pesticides on species that are listed as threatened or endangered under the Endangered Species Act (ESA) by ensuring the best available spatial data representing pesticide use sites are applied correctly. A decision matrix is presented that uses accuracy information from metadata contained in the US Department of Agriculture's (USDA's) Cropland Data Layer (CDL) and the Census of Agriculture (CoA) to improve how labeled pesticide use sites are spatially delineated.

Development of a mixed-source, single pesticide database for use in ecological risk assessment: quality control and data standardization practices.

Inclusion of pesticide monitoring data in pesticide risk assessment is important yet challenging for several reasons, including infrequent or irregular data collection, disparate sources procedures and associated monitoring periods, and interpretation of the data itself in a policy context. These challenges alone, left unaddressed, will likely introduce unintentional and unforeseen risk assessment conclusions. While individual water quality monitoring programs report standard operating procedures and quality control practices for their own data, cross-checking data for duplicated data from one database to another does not routinely occur.

Probabilistic co-occurrence assessment for suites of listed species.

Section 7 of the Endangered Species Act requires the US Environmental Protection Agency (US EPA) to consult with the Services (US Fish and Wildlife Service and National Marine Fisheries Service) over potential pesticide impacts on federally listed species. Consultation is complicated by the large number of pesticide products and listed species, as well as by lack of consensus on best practices for conducting co-occurrence analyses. Previous work demonstrates that probabilistic estimates of species' ranges and pesticide use patterns improve these analyses.

Response competition between neurons and antineurons in the mushroom body.

The mushroom bodies of Drosophila contain circuitry compatible with race models of perceptual choice. When flies discriminate odor intensity differences, opponent pools of αβ core Kenyon cells (on and off αβ KCs) accumulate evidence for increases or decreases in odor concentration. These sensory neurons and "antineurons" connect to a layer of mushroom body output neurons (MBONs) which bias behavioral intent in opposite ways.

Assessment of risks to listed species from the use of atrazine in the USA: a perspective.

Atrazine is a triazine herbicide used predominantly on corn, sorghum, and sugarcane in the US. Its use potentially overlaps with the ranges of listed (threatened and endangered) species. In response to registration review in the context of the Endangered Species Act, we evaluated potential direct and indirect impacts of atrazine on listed species and designated critical habitats.

Applying a Hybrid Modeling Approach to Evaluate Potential Pesticide Effects and Mitigation Effectiveness for an Endangered Fish in Simulated Oxbow Habitats.

The occurrence of some species listed under the United States' Endangered Species Act in agricultural landscapes suggests that their habitats could potentially be exposed to pesticides. However, the potential effects from such exposures on populations are difficult to estimate. Mechanistic models can provide an avenue to estimating the potential impacts on populations, considering realistic assumptions about the ecology of the species, the ecosystem it is part of, and the potential exposures within the habitat.

Acute and early life-stage toxicity of atrazine in sheepshead minnow (Cyprinodon variegatus).

Given the limited data available for estuarine/marine fish species and potential risk of being exposed to the herbicide atrazine, additional toxicity data regarding sensitive life-stages are needed. As such, this work sought to characterize: 1) the acute larval toxicity, and 2) early life-stage toxicity of technical atrazine in the model marine species sheepshead minnow (Cyprinodon variegatus). Atrazine was observed to be slightly to moderately toxic towards C.

Spray drift deposition comparison of fluorimetry and analytical confirmation techniques.

Tracer dyes are often used as surrogates to characterize pesticide spray drift and it is assumed that they accurately reflect analytical measurement of active ingredients; however, the validity of this assumption remains inconclusive. Consequently, the influence of measurement technique on the magnitude of deposition of spray drift was investigated using spray drift samples evaluated by traditional analytical techniques (HPLC-MS/MS) and fluorimetry (1,3,6,8-pyrene-tetra sulfonic acid tetrasodium salt dye tracer). The experiment was conducted in a low-speed wind tunnel under controlled meteorological conditions.

A Method to Screen for Consistency of Effect in Laboratory Toxicity Tests: A Case Study with Anurans and the Herbicide Atrazine.

This paper presents a semiquantitative method to help ecotoxicologists evaluate the consistency of data within the available peer-reviewed literature. In this case study, we queried whether there is consistent evidence of direct toxicity in Anurans exposed to atrazine at concentrations ≤ 100 μg/L under laboratory conditions. Atrazine was selected because of the relatively large repository of Anuran toxicity data.

Evaluating a developmental endocrine toxicity assay for Blanchard's cricket frog (Acris blanchardi) in outdoor enclosures.

A developmental toxicity testing design was evaluated for larval and post-metamorphic Blanchard's cricket frogs (Acris blanchardi) raised in outdoor enclosures. Larvae were chronically exposed to 17β-estradiol (0.0-2.

Chronic toxicity of technical atrazine to the fathead minnow (Pimephales promelas) during a full life-cycle exposure and an evaluation of the consistency of responses.

Fathead minnows (Pimephales promelas) were continuously exposed to the herbicide atrazine (0.15, 0.25, 0.