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At least 73 records · Page 4Linked to original sources
USGS2000

Use of biological characteristics of common carp ( Cyprinus carpio ) to indicate exposure to hormonally active agents in selected Minnesota streams, 1999

The presence of hormonally active agents (HAAs) was determined in selected Minnesota streams using biological characteristics (measures of endocrine disruption) of common carp ( Cyprinus carpio ) exposed to wastewater treatment plant (WWTP) effluent and runoff from agricultural and forested land. Four biological characteristics of common carp were used as indicators of HAAs in the streams selected for this study: (1) high concentrations of vitellogenin in male fish and low concentrations in female fish, (2) high or low plasma concentrations of the sex steroid hormones (17β-estradiol and 11-ketotestosterone), (3) low gonado-somatic index (GSI) (gonad weight divided by total body weight multiplied by 100) values, and (4) abnormal gonad histopathology (high percent of atretic oocytes in female ovaries and high percent ceroid/lipofuscin tissue in male or female gonads). The study design was a paired site approach targeting sites downstream and upstream of WWTP discharges on different streams. Male (221 individuals) and female (201 individuals) common carp were collected using electrofishing techniques from seven streams with sites at two locations (upstream and downstream of WWTPs), and eight sites located downstream of WWTPs with no upstream-paired sites. Samples were collected between August 3 and September 13, 1999. The presence of HAAs in selected Minnesota streams was indicated by biological characteristics in common carp. Biological characteristics used in this study identified WWTP effluent as a potential source of HAAs. Additionally, fish located at sites upstream of WWTP effluent primarily draining agricultural land show indications of HAAs, which may be the result of agricultural runoff or other sources of HAAs. There was variability among all sites and among sites within each site group. Differences among sites may be due to differences in water chemistry or fish exposure time. Natural variation in the biological characteristics may account for some of the differences observed in this study. This study and others indicate the presence of HAAs in surface water and the potential signs of endocrine disruption in resident fish populations. Detailed controlled studies could confirm the effects of particular chemicals such as pesticides or components of WWTPs on fish reproduction and population structure.

Minnesota↗
USGS1997

Water-quality assessment of the Ozark Plateaus study unit, Arkansas, Kansas, Missouri, and Oklahoma: Organic compounds in surface water, bed sediment, and biological tissue, 1992-95

Organic-compound samples, including pesticides and semi-volatiles, were collected from 1992-95 at 43 surface-water and 27 bed-sediment and biological-tissue sampling sites within the Ozark Plateaus National Water-Quality Assessment Program study unit. Most surface-water, bed-sediment, and biological-tissue sites have drainage basins predominantly in the Springfield and Salem Plateaus. At most surface-water sampling sites, one to three pesticide samples were collected in the spring and early summer of 1994 and 1995; two sites had additional samples collected either weekly, biweekly, or monthly from February 1994 through December 1994. At most bed-sediment and biological-tissue sampling sites, a single organic-compounds sample was collected. Agricultural pesticide use was approximately 4.9 million pounds of active ingredients per year from 1987-91 in the study unit and was generally greatest in the Springfield and Salem Plateaus pasturelands and in the Osage Plains and Mississippi Alluvial Plain cropland areas. The most frequently applied pesticide in the study unit was 2,4-D. Atrazine was the second most frequently applied pesticide. Corn, pasture, rice, sorghum, and soybeans received approximately 85 percent of the pesticides applied within the study unit. The highest pesticide application rate occurred on these crops in the Mississippi Alluvial and Osage Plains. Pastureland was the crop type that received the greatest amount of pesticides in 53 of the 96 counties in the study unit. The most commonly detected herbicide (63 samples) in surface water was atrazine. Five other pesticides--desethylatrazine, tebuthiuron, prometon, metolachlor, and simazine--were detected in 15 or more samples. The most commonly detected insecticide (13 samples) was p,p'-DDE. Two other insecticides, diazinon and cis-permethrin, were detected in seven or more samples. Pesticides were detected at 39 surface-water sites; samples collected at Yocum Creek near Oak Grove, Ark. had the most pesticide detections (13). Seventeen other sites had samples with six or more pesticide detections. Analysis of pesticide data collected at surface-water sites indicates that the largest variety of different pesticides detected (18) was in small, agricultural drainage basins; the largest percentage of detections of a single pesticide (about 80) was in medium, agricultural basins. Pesticide concentrations were small, and in most cases, at or near the detection limit. Maximum concentrations ranged from 0.001 to 0.007 micrograms per liter (mg/L) at small, forest sites; 0.001 to 0.029 mg/L at medium, forest sites; 0.001 to 0.079 mg/L at small, agricultural sites; and 0.003 to 0.29 mg/L at medium, agricultural sites. Pesticides were detected significantly more often in medium, agricultural basins in the Springfield Plateau. The most commonly detected (13 samples) organic compound in bed sediment, in concentrations noticeably above background levels, was 2,6-dimethylnaphthalene; the maximum concentration of 2,6-dimethylnaphthalene was 130 micrograms per kilogram. Seventeen or more compounds were detected in bed-sediment samples collected at three sites. Four compounds were detected in biological-tissue samples: p,p'-DDT in Corbicula fluminea (Asiatic clam) tissue collected at the Osage River near St. Thomas, Mo. and cis-chlordane, trans-chlordane, and trans-nonachlor in C. fluminea tissue collected at the James River near Boaz, Mo. Organic compounds collected at surface-water, bed-sediment, or biological-tissue sampling sites were not detected in concentrations that exceeded any health criteria or standards. Based on this information, organic compounds do not pose any widespread or persistent problems in the study unit.

Arkansas, Kansas, Missouri, Oklahoma↗
USGS1997

Occurrence and Distribution of Organochlorine Compounds in Biological Tissue and Bed Sediment From Streams in the Trinity River Basin, Texas, 1992-93

This report describes the occurrence and distribution of organochlorine compounds in biological tissue and bed sediment from the Trinity River Basin study area of the National Water-Quality Assessment Program. Concentrations of organochlorine pesticides, polychlorinated biphenyls (PCBs), and other organochlorine compounds were determined in biological tissue and surficial bed sediment from 16 stream sites in the Trinity River Basin of east-central Texas. Asiatic clams (Corbicula fluminea) were collected at 10 sites, and fish, including blue catfish (Ictalurus furcatus), common carp (Cyprinus carpio), bluegill (Lepomis cyanellus), and yellow bullhead (Ameiurus natalis) were collected at all mainstem and two tributary sites. Thirty of the 36 compounds analyzed in biological tissue or surficial bed sediment were detected in one or both media. Overall, more organochlorine compounds were detected in bed sediment than in biological tissue; however, various chlordane isomers, DDT metabolites, and PCBs were detected more frequently in tissue than in sediment. The chlordane isomers and PCBs that were detected more frequently in biological tissue also were detected more frequently at urban sites than at agricultural sites. Organochlorine compound concentrations generally were highest in fish tissue from Trinity River mainstem sites. Fish tissue from the mainstem sites contained a higher percentage of lipids than did fish- and clam-tissue samples from the tributary sites.

Water-Resources Investigations Report↗
USGS1999

Selected aquatic biological investigations in the Great Salt Lake basins, 1875-1998, National Water-Quality Assessment Program

This report summarizes previous investigations of aquatic biological communities, habitat, and contaminants in streams and selected large lakes within the Great Salt Lake Basins study unit as part of the U.S. Geological Survey’s National Water-Quality Assessment Program (NAWQA). The Great Salt Lake Basins study unit is one of 59 such units designed to characterize water quality through the examination of chemical, physical, and biological factors in surface and ground waters across the country. The data will be used to aid in the planning, collection, and analysis of biological information for the NAWQA study unit and to aid other researchers concerned with water quality of the study unit. A total of 234 investigations conducted during 1875-1998 are summarized in this report. The studies are grouped into three major subjects: (1) aquatic communities and habitat, (2) contamination of streambed sediments and biological tissues, and (3) lakes. The location and a general description of each study is listed. The majority of the studies focus on fish and macroinvertebrate communities. Studies of algal communities, aquatic habitat, riparian wetlands, and contamination of streambed sediment or biological tissues are less common. Areas close to the major population centers of Salt Lake City, Provo, and Logan, Utah, are generally well studied, but more rural areas and much of the Bear River Basin are lacking in detailed information, except for fish populations.

Idaho, Utah, Wyoming↗
USGS2001

Biological treatability and environmental impact of ozonation of spent reactive dyebaths

The effect of ozonation of spent reactive dyebaths on both subsequent biological wastewater treatment systems and ultimate aquatic toxicity of effluents from the wastewater treatment plant was determined. Actual spent dyebaths from a textile plant were ozonated to remove color. The ozonated and untreated control dyebaths were diluted to produce wastewaters similar in dissolved solids content to wastewaters typically discharged by a textile plant. These wastewaters were subjected to biological treatment, and effluent generated by the biological treatment was tested for toxicity to Ceriodaphnia dubia (C dubia). Higher reproduction in the ozonated wastewaters compared to those receiving only biological treatment suggested that ozonation of the spent dyebath tended to reduce the toxicity imparted by the wastewater after biological treatment.

AATCC Review↗
USGS2011

Weeds of Hawaii’s lands devoted to watershed protection and biodiversity conservation: Role of biological control as the missing piece in an integrated pest management strategy

Despite Hawaii’s reputation as an extinction icon, significant biological resources remain, especially in watersheds, natural areas, and specialized edaphic sites (e.g., lava dry forest, coastal). While direct habitat destruction by humans continues, human-facilitated biological invaders are currently the primary agents of continuing degradation. The ability of invasive plants to have prolific seed production, efficient dispersal systems, and to become established in dense vegetation, complicated by Hawaii’s rugged topography, appears to render mechanical and chemical control as mere holding actions. Costly, ‘environmentally unfriendly’, and often ineffective, strategies using chemical and mechanical control on a large scale, despite the most valiant of efforts, can be viewed simply as attempts to buy time. Without increased levels of safely tested biological control, the seemingly inevitable result is the landscape level transformation of native forests, with potentially catastrophic consequences to cultural, biological, water, and economic resources. Increased levels of effective biological control for certain intractable invasive species appear to comprise a conspicuous ‘missing piece’ in our efforts to protect Hawaiian watersheds and other conservation lands.

Hawaii↗
USGS2026

Global framework for communication of biological invasion risks

Biological invasions, driven by the spread of non-native species, have become a critical global issue because of their far-reaching ecological and socioeconomic impacts. Effective communication of the risks of biological invasions is essential for implementing robust policy and legislation and gaining public support for conservation efforts. However, current policies often suffer from fragmentation and ineffectiveness, largely due to inadequate risk communication and complex multilevel governance. To address this challenge, we develop a global framework designed to enhance clearer communication about biological invasion risks. The framework contextualizes key terms across three domains in invasion science: species invasiveness, risk analysis, and decision support tools. Using both diffusion-of-English and ecology-of-language paradigms, and following a three-step process involving preliminary consensus, AI querying, and ground-truthing with final consensus, we validate the framework in 70 non-English languages which, together with English, have official status in at least one country and collectively cover all 195 countries worldwide. Our findings reveal that while terminology for risk analysis is well established, terminology for species invasiveness and, especially, for decision support tools remains underdeveloped in many languages, hindering effective communication and policy implementation. Our framework underscores the importance of cultural and political neutrality. By promoting clearer risk communication among scientists, policymakers, and the public globally, we aim to reduce policy fragmentation and foster enhanced collaboration in risk mitigation. We recommend expanding multilingual decision support tools to include the full risk analysis process: risk identification, risk assessment, and risk management. This will support intergovernmental mitigation efforts and promote a unified global response to biological invasions.

Management of Biological Invasions↗
USGS2025

From subsidies to stressors: Shifting ecological baselines alter biological responses to nutrients in highly modified agricultural streams

Subsidy–stress gradients offer a useful framework for understanding ecological responses to perturbation and may help inform ecological metrics in highly modified systems. Historic, region-wide shifts from bottomland hardwood forest to row crop agriculture can cause positively skewed impact gradients in alluvial plain ecoregions, resulting in tolerant organisms that typically exhibit a subsidy response (increased abundance in response to environmental stressors) shifting to a stress response (declining abundance at higher concentrations). As a result, observed biological tolerance in modified ecosystems may differ from less modified regions, creating significant challenges for detecting biological responses to restoration efforts. Using the agriculturally dominated Mississippi Alluvial Plain (MAP) ecoregion in Mississippi, USA, as a case study, we tested the hypothesis that macroinvertebrate taxa that typically display a subsidy response to nutrient enrichment in less modified ecoregions (i.e., nutrient-tolerance) shift to a stress response to increasing nutrients in highly modified watersheds with elevated baseline nutrient conditions (i.e., nutrient intolerance). The abundance and diversity of MAP-specific intolerant taxa identified with threshold indicator taxa analysis were either unresponsive or exhibited a subsidy response to increasing nutrients in less modified ecoregions in Mississippi with less land alteration and lower nutrient concentrations, but declined at higher concentrations, providing evidence for a stress response to elevated nutrients in the MAP. Additionally, MAP-specific tolerant and intolerant taxa richness responded to increased nutrients predictably and consistently across space and time within the MAP. However, in MAP streams, elevated specific conductance was predicted to dampen the response of tolerant and intolerant taxa richness to increasing nutrient concentrations, highlighting the importance of considering multistressor interactions when interpreting biological data. Lastly, we demonstrate the efficacy of this approach with sediment bacterial communities characterized with amplicon sequencing, which lack sufficient life history characteristics necessary for the development of multimetric indices. Both macroinvertebrate and bacterial communities responded similarly to increasing nutrient concentrations, suggesting DNA-based approaches may provide an efficient biological assessment tool for monitoring water quality improvements in highly modified watersheds.

Mississippi↗
USGS2020

An interactive decision-making tool for evaluating biological and statistical standards of migrating fish survival past hydroelectric dams

Quantifying the downstream survival of migrating fish past dams is critical for conservation efforts. Regulators require assessments of survival as a condition of operation. Failure to meet an established survival standard may result in required operational or costly structural changes at a facility. Establishing the survival standard, as well as the rules of assessment, is a point of contention between regulators and operators. Management goals are based on biological criteria, but there are inherent statistical and probabilistic trade-offs when choosing a standard value and the method for assessment. We make a distinction between a “biological” goal (the conservation goal) and a “statistical” standard (a function of the biological goal, sample size, assessment method, and years of consecutive evaluation). An effective statistical standard maximizes true positives (passing the standard when the biological goal is being met) and true negatives (failing the standard when the goal is not being met), while minimizing false negatives and false positives. We explored the effects of sample size, true survival, and assessment methods on the probability of passing different statistical standards by simulating survival studies (simulating mark-recapture experiments). We observed a strong influence of assessment methods on the probability of making the right decision (true positive or true negative), especially when sample size, and recapture probability was low. As a support tool, we developed an interactive user interface to explore specific scenarios, and to aid communication among decision-makers.

River Research and Applications↗
USGS2017

Biological and social outcomes of antler point restriction harvest regulations for white-tailed deer

Selective harvest criteria, such as antler point restrictions (APRs), have been used to regulate harvest of male ungulates; however, comprehensive evaluation of the biological and social responses to this management strategy is lacking. In 2002, Pennsylvania adopted new APRs for white-tailed deer ( Odocoileus virginianus ) that required, depending on wildlife management unit, ≥3 or ≥4 points on 1 antler for legal harvest. Historically, harvest rates of subadult (1.5 yr old) and adult (≥2.5 yr old) antlered males averaged 0.80. Antler point restrictions were designed to protect ≥50% of subadult males from harvest. Most adult males remained legal for harvest. We estimated harvest rates, survival rates, and cause-specific mortality of radio-collared male deer (453 subadults, 103 adults) in 2 wildlife management units (Armstrong and Centre counties) to evaluate biological efficacy of APRs to increase recruitment of adult males during 2002–2005. We administered statewide deer hunter surveys before and after each hunting season over the same 3 years to evaluate hunter attitudes toward APRs. We conducted 2 types of surveys: a simple random sample of all license buyers for each survey and a longitudinal panel of hunters who completed all 6 surveys. At the same time APRs were implemented, the Pennsylvania Game Commission (PGC) increased antlerless harvests to reduce deer density to meet deer management goals. Survival rates varied by month and age but not between study areas or among years after implementation of APRs. Monthly survival rates for subadults ranged from 0.64 to 0.97 during hunting seasons and 0.95 to 0.99 during the non-hunting period. Annual survival of subadults was 0.46 (95% CI = 0.41–0.52). Adult monthly survival rates ranged from 0.36 to 0.95 during hunting seasons and we had no mortalities during the non-hunting period. Annual survival of adults was 0.28 (95% CI = 0.22–0.35). Antler point restrictions successfully reduced harvest rate for subadults to 0.31 (95% CI = 0.23–0.38), and approximately 92% of these deer survived to the following hunting season. Vehicle collisions were the greatest source of mortality outside the hunting season for subadults and adults. Also, we observed decreased harvest rates for adults (0.59, 95% CI = 0.40–0.72), although nearly all were legal for harvest. Of radio-collared subadults, 6–11% were harvested with sub-legal antlers, indicating hunters generally complied with APRs. Overall, antlered harvest declined statewide and in our study areas, in part because of APRs but also because of increased antlerless harvests that reduced the statewide population from 1.49 million deer in 2000 to 1.14 million deer in 2005. However, between 2000 and 2005, harvest of adult males increased by 976 (112%) in Armstrong County, decreased by 29 (−3%) in Centre County, and increased by 14,285 (29%) statewide because more males survived to the 3- and 4-year-old age classes. Proportion of hunters from the random sample surveys who supported statewide APRs varied among years between 0.61 (95% CI = 0.59–0.64) and 0.70 (95% CI = 0.66–0.73). The proportion of hunters from the longitudinal panel who supported APRs did not increase as hunters gained experience under the new regulations; 0.23 were more supportive, 0.29 were less supportive, and 0.48 were unchanged in their level of agreement after 3 years. Although >50% of hunters supported APRs throughout the study, support for the PGC's deer management program declined; 41% of the longitudinal panel of hunters rated the deer management program lower after 3 years and 21% rated it higher. We considered APRs biologically successful because of decreased subadult harvest rates and increased harvest of adult males with larger antlers. Likewise, because the majority of hunters supported APRs throughout the study, we considered APRs socially successful. However, we predicted APRs would become increasingly popular after hunters experienced biological results of APRs, but there was little change in support. We believe hunters formed an initial impression of the effects of APRs, and additional experience and information failed to change their opinion. Furthermore, the concurrent reduction in overall deer densities to accommodate more males in the population and to meet agency deer population goals likely further reduced support for APRs. We found APRs as implemented in Pennsylvania to be enforceable, adhered to by hunters, and successful in recruiting more antlered males to older age classes. To facilitate social acceptance of these regulation changes, we found that obtaining support before the changes were implemented may have been important because most hunters did not change their opinions about APRs after 3 years of experience with the new regulations.

Pennsylvania↗
USGS2014

Correspondence of biological condition models of California streams at statewide and regional scales

We used boosted regression trees (BRT) to model stream biological condition as measured by benthic macroinvertebrate taxonomic completeness, the ratio of observed to expected (O/E) taxa. Models were developed with and without exclusion of rare taxa at a site. BRT models are robust, requiring few assumptions compared with traditional modeling techniques such as multiple linear regression. The BRT models were constructed to provide baseline support to stressor delineation by identifying natural physiographic and human land use gradients affecting stream biological condition statewide and for eight ecological regions within the state, as part of the development of numerical biological objectives for California’s wadeable streams. Regions were defined on the basis of ecological, hydrologic, and jurisdictional factors and roughly corresponded with ecoregions. Physiographic and land use variables were derived from geographic information system coverages. The model for the entire state ( n  = 1,386) identified a composite measure of anthropogenic disturbance (the sum of urban, agricultural, and unmanaged roadside vegetation land cover) within the local watershed as the most important variable, explaining 56 % of the variance in O/E values. Models for individual regions explained between 51 and 84 % of the variance in O/E values. Measures of human disturbance were important in the three coastal regions. In the South Coast and Coastal Chaparral, local watershed measures of urbanization were the most important variables related to biological condition, while in the North Coast the composite measure of human disturbance at the watershed scale was most important. In the two mountain regions, natural gradients were most important, including slope, precipitation, and temperature. The remaining three regions had relatively small sample sizes ( n  ≤ 75 sites) and had models that gave mixed results. Understanding the spatial scale at which land use and land cover affect taxonomic completeness is imperative for sound management. Our results suggest that invertebrate taxonomic completeness is affected by human disturbance at the statewide and regional levels, with some differences among regions in the importance of natural gradients and types of human disturbance. The construction and application of models similar to the ones presented here could be useful in the planning and prioritization of actions for protection and conservation of biodiversity in California streams.

California↗
USGS2006

The role of biological uptake in iron and manganese cycling in Lake Baikal

The role of biological uptake in the internal cycling of Fe and Mn in Lake Baikal was quantified. Biological uptake, sedimentation consisting of the biogenic and lithogenic fluxes, and remineralization have been evaluated. The results of calculations show that about 5-10% of Fe and Mn accumulated in the lake are annually taken up by biota. More than 80% of this amount is again recycled after remineralization of biological material. At this, the biogenic fluxes of Fe and Mn are 2-4 times less compared to lithogenic ones. Thus not only is oxidation of Fe and Mn within the water column highly enriched in the oxygen that results in settling of Fe and Mn oxides, but also intensive biological uptake of these elements contributes to their fast removal from internal cycling. However, essential remineralization makes this process of minor importance to Fe and Mn cycling in Lake Baikal. ?? Springer 2006.

Conference Paper↗
USGS2009

Impact of biological soil crusts and desert plants on soil microfaunal community composition

Carbon and nitrogen are supplied by a variety of sources in the desert food web; both vascular and non-vascular plants and cyanobacteria supply carbon, and cyanobacteria and plant-associated rhizosphere bacteria are sources of biological nitrogen fixation. The objective of this study was to compare the relative influence of vascular plants and biological soil crusts on desert soil nematode and protozoan abundance and community composition. In the first experiment, biological soil crusts were removed by physical trampling. Treatments with crust removed had fewer nematodes and a greater relative ratio of bacterivores to microphytophages than treatments with intact crust. However, protozoa composition was similar with or without the presence of crusts. In a second experiment, nematode community composition was characterized along a spatial gradient away from stems of grasses or shrubs. Although nematodes generally occurred in increasing abundance nearer to plant stems, some genera (such as the enrichment-type Panagrolaimus) increased disproportionately more than others (such as the stress-tolerant Acromoldavicus). We propose that the impact of biological soil crusts and desert plants on soil microfauna, as reflected in the community composition of microbivorous nematodes, is a combination of carbon input, microclimate amelioration, and altered soil hydrology. ?? Springer Science + Business Media B.V. 2009.

Plant and Soil↗
USGS2022

Biological assessments of aquatic ecosystems

The aim of biological assessments (or bioassessments) is to provide decision makers and managers the scientific information and tools needed to protect and restore aquatic life. Biological assessments typically include several critical elements, including development of ecological indicators, indices of ecological status, benchmarks by which to gauge impairment, ways to identify the stressors causing ecological impairment, and biological criteria and standards to protect aquatic life. New scientific tools are emerging that should improve the accuracy and precision of biological assessments, but the major challenges to effective protection and restoration of aquatic life are political and economic rather than scientific.

Book chapter↗
USGS2022

A biological condition gradient for coral reefs in the US Caribbean Territories: Part I. Coral narrative rules

As coral reef condition and sustainability continue to decline worldwide, losses of critical habitat and their ecosystem services have generated an urgency to understand and communicate reef response to management actions, environmental contamination, and natural disasters. Increasingly, coral reef protection and restoration programs emphasize the need for robust assessment tools for protecting high-quality waters and establishing conservation goals. Of equal importance is the need to communicate assessment results to stakeholders, beneficiaries, and the public so that environmental consequences of decisions are understood. The Biological Condition (BCG) model provides a structure to evaluate the condition of a coral reef in increments of change along a gradient of human disturbance. Communication of incremental change, regardless of direction, is important for decision makers and the public to better understand what is gained or lost depending on what actions are taken. We developed a narrative (qualitative) Biological Condition Gradient (BCG) from the consensus of a diverse expert panel to provide a framework for coral reefs in US Caribbean Territories. The model uses narrative descriptions of biological attributes for benthic organisms to evaluate reefs relative to undisturbed or minimally disturbed conditions. Using expert elicitation, narrative decision rules were proposed and deliberated to discriminate among six levels of change along a gradient of increasing anthropogenic stress. Narrative rules for each of the BCG levels are presented to facilitate the evaluation of benthic communities in coral reefs and provide specific narrative features to detect changes in coral reef condition and biological integrity. The BCG model can be used in the absence of numeric, or quantitative metrics, to evaluate actions that may encroach on coral reef ecosystems, manage endangered species habitat, and develop and implement management plans for marine protected areas, watersheds, and coastal zones. The narrative BCG model is a defensible model and communication tool that translates scientific results so the nontechnical person can understand and support both regulatory and non-regulatory water quality and natural resource programs.

Puerto Rico, U.S. Virgin Islands↗
USGS2023

Less is more: Less herbicide does more when biological control is present in Pontederia crassipes

An experiment along with simulation modeling was applied to study the combinations of herbicide treatment and biological control that best limit invasive water hyacinth ( Pontederia crassipes , formerly Eichhornia crassipes ) in freshwater aquatic systems. The experiment consisted of 14 different treatments of P. crassipes in 1.67 m 2 outdoor tank mesocosms. Seven treatments were with and seven were without insect biological control agents, Neochetina eichhorniae . In both of the sets of seven treatments, there was one no-herbicide treatment, a one-time full-strength herbicide treatment with 40 %, 80 % and 100 % coverage of the P. crassipes , and a one-time half-strength herbicide treatment with 40 %, 80 %, and 100 % surface area coverage. An overarching hypothesis was that leaving part of a tank unsprayed, providing habitat for the maintenance of biological control agents, would optimize control. Data from the experiment, measured on five days over the 167-day period, were used to calibrate a difference equation model of P. crassipes with and without the biological control agent. The model was then used to project longer term dynamics of the system. The model predicted that an initial one-time herbicide treatment, combined with application of the biocontrol agent at 80 % areal coverage, could maintain P. crassipes at levels lower than the carrying capacity of the plant's biomass over the long term, though not enough that N. eichhorniae would be considered, by itself, a highly effective control. However, the results suggest that a combination of biocontrol with 80 % spraying coverage every 600 days or so would be an effective integrated biocontrol strategy for maintaining decreased P. crassipes biomass at low levels over the long term.

Ecological Modelling↗
USGS2008

Biomorphodynamics: Physical-biological feedbacks that shape landscapes

Plants and animals affect morphological evolution in many environments. The term "ecogeomorphology" describes studies that address such effects. In this opinion article we use the term "biomorphodynamics" to characterize a subset of ecogeomorphologic studies: those that investigate not only the effects of organisms on physical processes and morphology but also how the biological processes depend on morphology and physical forcing. The two-way coupling precipitates feedbacks, leading to interesting modes of behavior, much like the coupling between flow/sediment transport and morphology leads to rich morphodynamic behaviors. Select examples illustrate how even the basic aspects of some systems cannot be understood without considering biomorphodynamic coupling. Prominent examples include the dynamic interactions between vegetation and flow/sediment transport that can determine river channel patterns and the multifaceted biomorphodynamic feedbacks shaping tidal marshes and channel networks. These examples suggest that the effects of morphology and physical processes on biology tend to operate over the timescale of the evolution of the morphological pattern. Thus, in field studies, which represent a snapshot in the pattern evolution, these effects are often not as obvious as the effects of biology on physical processes. However, numerical modeling indicates that the influences on biology from physical processes can play a key role in shaping landscapes and that even local and temporary vegetation disturbances can steer large-scale, long-term landscape evolution. The prevalence of biomorphodynamic research is burgeoning in recent years, driven by societal need and a confluence of complex systems-inspired modeling approaches in ecology and geomorphology. To make fundamental progress in understanding the dynamics of many landscapes, our community needs to increasingly learn to look for two-way, biomorphodynamic feedbacks and to collect new types of data to support the modeling of such emergent interactions. Copyright 2008 by the American Geophysical Union.

Water Resources Research↗
USGS2011

Using consumption rate to assess potential predators for biological control of white perch

Control of undesirable fishes is important in aquatic systems, and using predation as a tool for biological control is an attractive option to fishery biologists. However, determining the appropriate predators for biological control is critical for success. The objective of this study was to evaluate the utility of consumption rate as an index to determine the most effective predators for biological control of an invasive fish. Consumption rate values were calculated for nine potential predators that prey on white perch Morone americana in Branched Oak and Pawnee reservoirs, Nebraska. The consumption rate index provided a unique and insightful means of determining the potential effectiveness of each predator species in controlling white perch. Cumulative frequency distributions facilitated interpretation by providing a graphical presentation of consumption rates by all individuals within each predator species. Largemouth bass Micropterus salmoides , walleye S ander vitreus and sauger S. canadensis were the most efficient white perch predators in both reservoirs; however, previous attempts to increase biomass of these predators have failed suggesting that successful biological control is unlikely using existing predator species in these Nebraska reservoirs.

Nebraska↗