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When best intentions are not enough - A collaboration between scientists, policymakers, and an agricultural community

Rocky Mountain National Park is a Congressionally mandated Clean Air Act Class I Area, but years of research have documented evidence of biogeochemical and ecological change caused by atmospheric deposition of nitrogen. A coalition of government agencies—National Park Service, the Environmental Protection Agency Region 8, and the State of Colorado—developed the 2007 Nitrogen Deposition Reduction Plan to reduce wet nitrogen deposition to the park from the baseline in 2006 by 50% by 2032. Fifty-four percent of wet nitrogen deposition is ammonium, primarily sourced from industrial cattle and dairy operations east of the park. An Agriculture Subcommittee, meeting with regulatory and management agencies and scientists since 2006, has explored voluntary options to reduce ammonia emissions. Ammonia emissions are unregulated in the U.S. Despite sustained efforts, neither ammonium deposition nor total inorganic nitrogen deposition have declined at the rate determined to reach the targeted value by 2032. In fact, ammonia is increasing over the Front Range agricultural area. Wet nitrogen deposition in 2024 was 2.81 kg N ha −1 yr −1 , 0.61 kg N ha −1 yr −1 higher than targeted in the Nitrogen Deposition Reduction Plan. The collaborative approach between agricultural producers, regulatory entities, and resource managers is not working, but not for lack of effort by all parties. Cattle process nitrogen inefficiently, and while management practices can somewhat reduce the proportion of ammonia emitted from feedlots, with more than one million head of cattle east of Rocky Mountain National Park, large-scale reductions are unlikely. New programs to reduce emissions of nitrogen oxides (46% of wet nitrogen deposition) may reduce nitrogen deposition that is changing park ecosystems. Improved integration of crop and livestock agriculture and valuation of the ecosystem services and economy of Rocky Mountain National Park alongside agricultural value are topics for further discussion. Implications : Nitrogen deposition in precipitation to Rocky Mountain National Park has changed natural ecosystems. To protect its Clean Air Act Class I status a 2007 Nitrogen Deposition Reduction Plan agreed upon by state and federal agencies set a goal to reduce wet nitrogen deposition to the Park by half by 2032. Industrial livestock operations are a large source of nitrogen; an Agriculture Subcommittee explored voluntary options to reduce emissions from cattle. Despite sustained efforts nitrogen deposition has not declined. Further reductions in industry and transportation emissions will be needed reduce nitrogen deposition to Rocky Mountain National Park.

Colorado↗

Conservation endocrinology

Endocrinologists can make significant contributions to conservation biology by helping to understand the mechanisms by which organisms cope with changing environments. Field endocrine techniques have advanced rapidly in recent years and can provide substantial information on the growth, stress, and reproductive status of individual animals, thereby providing insight into current and future responses of populations to changes in the environment. Environmental stressors and reproductive status can be detected nonlethally by measuring a number of endocrine-related endpoints, including steroids in plasma, living and nonliving tissue, urine, and feces. Information on the environmental or endocrine requirements of individual species for normal growth, development, and reproduction will provide critical information for species and ecosystem conservation. For many taxa, basic information on endocrinology is lacking, and advances in conservation endocrinology will require approaches that are both “basic” and “applied” and include integration of laboratory and field approaches.

BioScience↗

Geophysical logging data from the Mills Gap Road area near Asheville, North Carolina

In September 2009, the U.S. Geological Survey (USGS) was requested to assist the Environmental Protection Agency (EPA) Region 4 Superfund Section in the development of a conceptual groundwater flow model in the area of the Mills Gap Road contaminant investigation near Asheville, North Carolina (Site ID A4P5) through an Interagency Grant and work authorization IAD DW number 14946085. The USGS approach included the application of established and state-of-the-science borehole geophysical tools and methods used to delineate and characterize fracture zones in the regolith-fractured bedrock groundwater system. Borehole geophysical logs were collected in eight wells in the Mills Gap Road project area from January through June 2010. These subsurface data were compared to local surface geologic mapping data collected by the North Carolina Geological Survey (NCGS) from January through May 2010.

North Carolina↗

Elevation derivatives for national applications

The Elevation Derivatives for National Applications (EDNA) project is a multi-agency effort to develop standard topographically derived layers for use in hydrologic and environmental modeling. The EDNA takes advantage of the seamless and filtered characteristics for the National Elevation Dataset (NED) to create a hydrologically conditioned Digital Elevation Model (DEM) useful for modeling applications. The goals of the project are to create a hydrologically conditioned DEM and systematically extract a set of standard derivatives that can be used to facilitate data integration with other U.S. Geological Survey (USGS) framework data sets such as the National Hydrography Dataset (NHD) and the Watershed Boundaries Dataset (WBD).

Fact Sheet↗

Use of StreamStats in the Upper French Broad River Basin, North Carolina: A Pilot Water-Resources Web Application

StreamStats is a Web-based Geographic Information System (GIS) application that was developed by the U.S. Geological Survey (USGS) in cooperation with Environmental Systems Research Institute, Inc. (ESRI) to provide access to an assortment of analytical tools that are useful for water-resources planning and management. StreamStats allows users to easily obtain streamflow statistics, basin characteristics, and descriptive information for USGS data-collection sites and selected ungaged sites. StreamStats also allows users to identify stream reaches upstream and downstream from user-selected sites and obtain information for locations along streams where activities occur that can affect streamflow conditions. This functionality can be accessed through a map-based interface with the user's Web browser or through individual functions requested remotely through other Web applications.

North Carolina↗

Pennsylvania StreamStats: A web-based application for obtaining water-resource-related information

StreamStats is a national web-based Geographic Information System (GIS) application, developed by the U.S. Geological Survey (USGS), in cooperation with Environmental Systems Research Institute, Inc., to provide a variety of water-resource-related information. Users can easily obtain descriptive information, basin characteristics, and streamflow statistics for USGS streamgages and ungaged stream locations throughout Pennsylvania. StreamStats also allows users to search upstream and (or) downstream from user-selected points to identify locations of and obtain information for water-resource-related activities, such as dams and streamgages.

Pennsylvania↗

StreamStats in North Carolina: A water-resources Web application

A statewide StreamStats application for North Carolina was developed in cooperation with the North Carolina Department of Transportation following completion of a pilot application for the upper French Broad River basin in western North Carolina (Wagner and others, 2009). StreamStats for North Carolina, available at http://water.usgs.gov/osw/streamstats/north_carolina.html, is a Web-based Geographic Information System (GIS) application developed by the U.S. Geological Survey (USGS) in consultation with Environmental Systems Research Institute, Inc. (Esri) to provide access to an assortment of analytical tools that are useful for water-resources planning and management (Ries and others, 2008). The StreamStats application provides an accurate and consistent process that allows users to easily obtain streamflow statistics, basin characteristics, and descriptive information for USGS data-collection sites and user-selected ungaged sites. In the North Carolina application, users can compute 47 basin characteristics and peak-flow frequency statistics (Weaver and others, 2009; Robbins and Pope, 1996) for a delineated drainage basin. Selected streamflow statistics and basin characteristics for data-collection sites have been compiled from published reports and also are immediately accessible by querying individual sites from the web interface. Examples of basin characteristics that can be computed in StreamStats include drainage area, stream slope, mean annual precipitation, and percentage of forested area (Ries and others, 2008). Examples of streamflow statistics that were previously available only through published documents include peak-flow frequency, flow-duration, and precipitation data. These data are valuable for making decisions related to bridge design, floodplain delineation, water-supply permitting, and sustainable stream quality and ecology. The StreamStats application also allows users to identify stream reaches upstream and downstream from user-selected sites and obtain information for locations along streams where activities occur that may affect streamflow conditions. This functionality can be accessed through a map-based interface with the user’s Web browser, or individual functions can be requested remotely through Web services (Ries and others, 2008).

North Carolina↗

Technology advancement: A factor in increasing resource use

The specter of mineral resource scarcity has been repeatedly raised as a concern because ever-growing populations with seemingly insatiable appetites for minerals place claims against a finite resource endowment. This report analyzes how technology has helped to ease resource constraints, and uses case studies of aluminum, copper, potash, and sulfur minerals to identify the effects of technology on resource supply. In spite of heightened demand for and increased loss of resources to environmental policy and urbanization, mineral producers historically have been able to continually expand production and lower costs. Specific production increases for the years 1900-98 were: aluminum (3,250 percent), copper (2,465 percent), potash (3,770 percent), and sulfur (6,000 percent). For the same period, constant-dollar (1998) prices decreased: aluminum (90 percent), copper (75 percent), potash (94 percent), and sulfur (89 percent). The application of technology has made available mineral deposits that were previously overlooked or considered non-viable. Using technology, producers can meet the demand for stronger, energy-efficient, more environmentally safe products with less physical material. Technologies have been developed to increase the amount of materials recycled and remanufactured. Technology development can occur in breakthroughs, but most often advances incrementally. Technological development is driven by the profit motive.

Open-File Report↗

Colorado River fish monitoring in Grand Canyon, Arizona; 2000 to 2009 summary

Long-term fish monitoring in the Colorado River below Glen Canyon Dam is an essential component of the Glen Canyon Dam Adaptive Management Program (GCDAMP). The GCDAMP is a federally authorized initiative to ensure that the primary mandate of the Grand Canyon Protection Act of 1992 to protect resources downstream from Glen Canyon Dam is met. The U.S. Geological Survey's Grand Canyon Monitoring and Research Center is responsible for the program's long-term fish monitoring, which is implemented in cooperation with the Arizona Game and Fish Department, U.S. Fish and Wildlife Service, SWCA Environmental Consultants, and others. Electrofishing and tagging protocols have been developed and implemented for standardized annual monitoring of Colorado River fishes since 2000. In 2009, sampling occurred throughout the river between Lees Ferry and Lake Mead for 38 nights over two trips. During the two trips, scientists captured 6,826 fish representing 11 species. Based on catch-per-unit-effort, salmonids (for example, rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta)) increased eightfold between 2006 and 2009. Flannelmouth sucker (Catostomus latipinnis) catch rates were twice as high in 2009 as in 2006. Humpback chub (Gila cypha) catches were low throughout the 10-year sampling period.

Open-File Report↗

Validation of eDNA markers for New Zealand mudsnail surveillance and initial eDNA monitoring at Mississippi River Basin sites

The performance of newly developed New Zealand mudsnail ( Potamopyrgus antipodarum ; NZMS) genetic markers for environmental (eDNA) analysis of water were compared across two laboratories. The genetic markers were tested in four quantitative polymerase chain reaction assays targeting two regions of the NZMS mitochondrial genome, specifically the cytochrome c oxidase subunit 1 (coi) and cytochrome b (cytb) genes. In a blind study, analysts tested each sample eight times with each assay. There were 10 expected-negative samples from the Black River in La Crosse, Wisconsin, 10 expected-positive samples from the Black Earth Creek in Black Earth, Wisconsin, and 10 known-positive samples from the Black River spiked with NZMS DNA. Previously extracted samples, kept at the Upper Midwest Environmental Sciences Center, were pooled by sample location and then equal quantities were distributed between the Upper Midwest Environmental Sciences Center and the Molecular Conservation Genetics Laboratory at the University of Wisconsin-Stevens Point for analysis. The assays tested were (1) the assay targeting cytb with a minor groove binder probe described by Goldberg and others (2013), (2) the cytb assay with a modified double-quenched probe, (3) an assay targeting coi with a double-quenched probe, and (4) a duplex reaction combining the modified cytb assay and the coi assay. Samples were considered positive for the presence of NZMS DNA when quantitative polymerase chain reaction amplification and probe signal was higher than the normalized threshold value above baseline fluorescence. For the duplex assay, samples were considered positive only when both probe signals were higher than the normalized threshold value above baseline fluorescence. Positive results were then confirmed by sequencing the products. All four assays detected the DNA of NZMS in all expected-positive and known-positive samples in both labs. The modified cytb assay, the coi assay, and the duplex assay all failed to detect the DNA of NZMS in all expected-negative samples in both labs. The cytb assay, as described by Goldberg and others (2013), failed to detect the DNA of NZMS in all expected-negative samples for the Molecular Conservation Genetics Laboratory, but some reactions resulted in positive detection in late cycles for 9 of the 10 expected-negative samples at the Upper Midwest Environmental Sciences Center. Amplicons for expected-negative samples with positive reactions were sent for sequencing, and none were confirmed as NZMS. Six amplicons failed to give readable sequences, and three gave sequences without similarity to any known sequence in GenBank. Amplicons from each assay for one representative positive sample were sequenced and identified as NZMS with greater than 99 percent identity. The duplex assay was chosen as the most efficient assay and was used at the Upper Midwest Environmental Sciences Center to analyze triplicate samples from 29 streams in Wisconsin, 8 streams in Illinois, and 8 streams in Iowa. In order to verify results, additional triplicate samples were collected from two of the streams in Iowa and two of the streams in Wisconsin for analysis at the Molecular Conservation Genetics Laboratory. All samples at all sites were negative for NZMS DNA.

Illinois, Iowa, Wisconsin↗

Comparative toxicity of emulsifiable concentrate and suspension concentrate formulations of 2′,5-dichloro-4′-nitrosalicylanilide ethanolamine salt

The 2-aminoethanol salt of niclosamide (2′,5-dichloro-4′-nitrosalicylanilide) is a pesticide known as Bayluscide that is used in conjunction with TFM (4-nitro-3-[trifluoromethyl]phenol), also known as 3-trifluoromethyl-4-nitrophenol) to treat tributaries to the Great Lakes infested with invasive parasitic Petromyzon marinus (sea lamprey). Adding 0.5 to 2 percent Bayluscide with TFM can substantially reduce the amount of TFM required to achieve effective control. Currently, an emulsifiable concentrate (EC) formulation of Bayluscide is used in combination with TFM during some stream treatments completed by the Great Lakes Fishery Commission’s binational sea lamprey control program. The Bayluscide EC formulation is highly effective; however, it degrades application tubing, adheres to application equipment, and raises concerns for worker safety because of the solvent in the formulation, N-methyl-2-pyrrolidone. We collaborated with a pesticide formulation company to develop a Bayluscide 20-percent suspension concentrate (SC) formulation as a potential replacement for the Bayluscide 20-percent EC formulation. The 20-percent SC formulation was specifically developed using inert ingredients approved for use by the U.S. Environmental Protection Agency and the Health Canada Pest Management Regulatory Agency. Although approved for use, the inclusion of a small quantity of an antimicrobial in the formulation warranted evaluating the toxicological profile to sea lamprey and select nontarget fish species. We evaluated and compared the toxicity of the 20-percent SC formulation to the 20-percent EC formulation using continuous-flow diluter systems and larval sea lamprey and select cold-, cool-, and warm-water fish as test animals. Our results demonstrate comparable toxicological profiles between the two formulations with the 20-percent SC formulation being slightly less toxic to the nontarget species evaluated.

Open-File Report↗

Assessment of shallow ground-water quality in recently urbanized areas of Sacramento, California, 1998

Evidence for anthropogenic impact on shallow ground-water quality beneath recently developed urban areas of Sacramento, California, has been observed in the sampling results from 19 monitoring wells in 1998. Eight volatile organic compounds (VOCs), four pesticides, and one pesticide transformation product were detected in low concentrations, and nitrate, as nitrogen, was detected in elevated concentrations; all of these concentrations were below National and State primary and secondary maximum contaminant levels. VOC results from this study are more consistent with the results from urban areas nationwide than from agricultural areas in the Central Valley, indicating that shallow ground-water quality has been impacted by urbanization. VOCs detected may be attributed to either the chlorination of drinking water, such as trichloromethane (chloroform) detected in 16 samples, or to the use of gasoline additives, such as methyl tert-butyl ether (MTBE), detected in 2 samples. Pesticides detected may be attributed to use on household lawns and gardens and rights-of-way, such as atrazine detected in three samples, or to past agricultural practices, and potentially to ground-water/surface-water interactions, such as bentazon detected in one sample from a well adjacent to the Sacramento River and downstream from where bentazon historically was used on rice. Concentrations of nitrate may be attributed to natural sources, animal waste, old septic tanks, and fertilizers used on lawns and gardens or previously used on agricultural crops. Seven sample concentrations of nitrate, as nitrogen, exceeded 3.0 milligrams per liter, a level that may indicate impact from human activities. Ground-water recharge from rainfall or surface-water runoff also may contribute to the concentrations of VOCs and pesticides observed in ground water. Most VOCs and pesticides detected in ground-water samples also were detected in air and surface-water samples collected at sites within or adjacent to the recently developed urban areas. Five arsenic sample concentrations exceeded the U.S. Environmental Protection Agency (USEPA) primary maximum contaminant level (MCL) of 10 milligrams per liter adopted in 2001. Measurements that exceeded USEPA or California Department of Health Services recommended secondary maximum contaminant levels include manganese, iron, chloride, total dissolved solids, and specific conductance. These exceedances are probably a result of natural processes. Variations in stable isotope ratios of hydrogen (2H/1H) and oxygen (18O/16O) may indicate different sources or a mixing of recharge waters to the urban ground water. These variations also may indicate recharge directly from surface water in one well adjacent to the Sacramento River. Tritium concentrations indicate that most shallow ground water has been recharged since the mid-1950s, and tritium/helium-3 age dates suggest that recharge has occurred in the last 2 to 30 years in some areas. In areas where water table depths exceed 20 meters and wells are deeper, ground-water recharge may have occurred prior to 1950, but low concentrations of pesticides and VOCs detected in these deeper wells indicate a mixing of younger and older waters. Overall, the recently urbanized areas can be divided into two groups. One group contains wells where few VOCs and pesticides were detected, nitrate mostly was not detected, and National and State maximum contaminant levels, including the USEPA MCL for arsenic, were exceeded; these wells are adjacent to rivers and generally are characterized by younger water, shallow (1 to 4 meters) water table, chemically reducing conditions, finer grained sediments, and higher organics in the soils. In contrast, the other group contains wells where more VOCs, pesticides, and elevated nitrate concentrations were detected; these wells are farther from rivers and are generally characterized by a mixture of young and old waters, intermediate to deep (7 to 35 meters) wate

Scientific Investigations Report↗

Sediment Transport in the Bill Williams River and Turbidity in Lake Havasu During and Following Two High Releases from Alamo Dam, Arizona, in 2005 and 2006

Discharges higher than are typically released from Alamo Dam in west-central Arizona were planned and released in 2005, 2006, 2007, and 2008 to study the effects of these releases on the Bill Williams River and Lake Havasu, into which the river debouches. Sediment concentrations and water discharges were measured in the Bill Williams River, and turbidity, temperature, and dissolved oxygen were measured in Lake Havasu during and after experimental releases in 2005 and 2006 from Alamo Dam. Data from such releases will support ongoing ecological studies, improve environmentally sensitive management of the river corridor, and support the development of a predictive relationship between the operation of Alamo Dam and downstream flows and their impact on Lake Havasu and the Colorado River. Elevated discharges in the Bill Williams River mobilize more sediment than during more typical dam operation and can generate a turbidity plume in Lake Havasu. The intakes for the Central Arizona Project, which transfers Colorado River water to central and southern Arizona, are near the mouth of the Bill Williams River. Measurement of the turbidity and the development of the plume over time consequently were important components of the study. In this report, the measurements of suspended sediment concentration and discharges in the Bill Williams River and of turbidity in Lake Havasu are presented along with calculations of silt and sand loads in the Bill Williams River. Sediment concentrations were varied and likely dependent on a variable supply. Sediment loads were calculated at the mouth of the river and near Planet, about 10 km upstream from the mouth for the 2005 release, and they indicate that a net increase in transport of silt and a net decrease in the transport of sand occurred in the reach between the two sites.

Scientific Investigations Report↗

Assessment of nonpoint source chemical loading potential to watersheds containing uranium waste dumps associated with uranium exploration and mining, Browns Hole, Utah

During August of 2008, 35 solid-phase samples were collected from abandoned uranium waste dumps, undisturbed geologic background sites, and adjacent streambeds in Browns Hole in southeastern Utah. The objectives of this sampling program were (1) to assess impacts on human health due to exposure to radium, uranium, and thorium during recreational activities on and around uranium waste dumps on Bureau of Land Management lands; (2) to compare concentrations of trace elements associated with mine waste dumps to natural background concentrations; (3) to assess the nonpoint source chemical loading potential to ephemeral and perennial watersheds from uranium waste dumps; and (4) to assess contamination from waste dumps to the local perennial stream water in Muleshoe Creek. Uranium waste dump samples were collected using solid-phase sampling protocols. Solid samples were digested and analyzed for major and trace elements. Analytical values for radium and uranium in digested samples were compared to multiple soil screening levels developed from annual dosage calculations in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act's minimum cleanup guidelines for uranium waste sites. Three occupancy durations for sites were considered: 4.6 days per year, 7.0 days per year, and 14.0 days per year. None of the sites exceeded the radium soil screening level of 96 picocuries per gram, corresponding to a 4.6 days per year exposure. Two sites exceeded the radium soil screening level of 66 picocuries per gram, corresponding to a 7.0 days per year exposure. Seven sites exceeded the radium soil screening level of 33 picocuries per gram, corresponding to a 14.0 days per year exposure. A perennial stream that flows next to the toe of a uranium waste dump was sampled, analyzed for major and trace elements, and compared with existing aquatic-life and drinking-water-quality standards. None of the water-quality standards were exceeded in the stream samples.

Utah↗

Modeling the Water - Quality Effects of Changes to the Klamath River Upstream of Keno Dam, Oregon

The Link River to Keno Dam (Link-Keno) reach of the Klamath River, Oregon, generally has periods of water-quality impairment during summer, including low dissolved oxygen, elevated concentrations of ammonia and algae, and high pH. Efforts are underway to improve water quality in this reach through a Total Maximum Daily Load (TMDL) program and other management and operational actions. To assist in planning, a hydrodynamic and water-quality model was used in this study to provide insight about how various actions could affect water quality in the reach. These model scenarios used a previously developed and calibrated CE-QUAL-W2 model of the Link-Keno reach developed by the U.S. Geological Survey (USGS), Watercourse Engineering Inc., and the Bureau of Reclamation for calendar years 2006-09 (referred to as the "USGS model" in this report). Another model of the same river reach was previously developed by Tetra Tech, Inc. and the Oregon Department of Environmental Quality for years 2000 and 2002 and was used in the TMDL process; that model is referred to as the "TMDL model" in this report. This report includes scenarios that (1) assess the effect of TMDL allocations on water quality, (2) provide insight on certain aspects of the TMDL model, (3) assess various methods to improve water quality in this reach, and (4) examine possible water-quality effects of a future warmer climate. Results presented in this report for the first 5 scenarios supersede or augment those that were previously published (scenarios 1 and 2 in Sullivan and others [2011], 3 through 5 in Sullivan and others [2012]); those previous results are still valid, but the results for those scenarios in this report are more current.

Oregon↗

Cell penetrating peptide-mediated delivery of gene-silencing nucleic acids to the invasive common reed Phragmites australis via foliar application

As a popular tool for gene function characterization and gene therapy, RNA interference (RNAi)-based gene silencing has been increasingly explored for potential applications to control invasive species. At least two major hurdles exist when applying this approach to invasive plants: (1) the design and screening of species- and gene-specific biomacromolecules (i.e., gene-silencing agents or GSAs) made of DNA, RNA, or peptides that can suppress the expression of target genes efficiently, and (2) the delivery vehicle needed to penetrate plant cell walls and other physical barriers (e.g., leaf cuticles). In this study, we investigated the cell-penetrating peptide (CPP)-mediated delivery of multiple types of GSAs (e.g., double-stranded RNA (dsRNA), artificial microRNA (amiRNA), and antisense oligonucleotide (ASO)) to knock down a putative phytoene desaturase ( PDS ) gene in the invasive common reed ( Phragmites australis spp. australis ). Both microscopic and quantitative gene expression evidence demonstrated the CPP-mediated internalization of GSA cargos and transient suppression of PDS expression in both treated and systemic leaves up to 7 days post foliar application. Although various GSA combinations and application rates and frequencies were tested, we observed limitations, including low gene-silencing efficiency and a lack of physiological trait alteration, likely owing to low CPP payload capacity and the incomplete characterization of the PDS-coding genes (e.g., the recent discovery of two PDS paralogs) in P. australis . Our work lays a foundation to support further research toward the development of convenient, cost-effective, field-deployable, and environmentally benign gene-silencing technologies for invasive P. australis management.

Mississippi, Ohio↗

Reference intervals and physiologic alterations in hematologic and biochemical values of free-ranging desert tortoises in the Mojave Desert

Desert tortoise ( Gopherus agassizii ) populations have experienced precipitous declines resulting from the cumulative impact of habitat loss, and human and disease-related mortality. Evaluation of hematologic and biochemical responses of desert tortoises to physiologic and environmental factors can facilitate the assessment of stress and disease in tortoises and contribute to management decisions and population recovery. The goal of this study was to obtain and analyze clinical laboratory data from free-ranging desert tortoises at three sites in the Mojave Desert (California, USA) between October 1990 and October 1995, to establish reference intervals, and to develop guidelines for the interpretation of laboratory data under a variety of environmental and physiologic conditions. Body weight, carapace length, and venous blood samples for a complete blood count and clinical chemistry profile were obtained from 98 clinically healthy adult desert tortoises of both sexes at the Desert Tortoise Research Natural area (western Mojave), Goffs (eastern Mojave) and Ivanpah Valley (northeastern Mojave). Samples were obtained four times per year, in winter (February/March), spring (May/June), summer (July/August), and fall (October). Years of near-, above- and below-average rainfall were represented in the 5 yr period. Minimum, maximum and median values, and central 95 percentiles were used as reference intervals and measures of central tendency for tortoises at each site and/or season. Data were analyzed using repeated measures analysis of variance for significant ( P < 0.01) variation on the basis of sex, site, season, and interactions between these variables. Significant sex differences were observed for packed cell volume, hemoglobin concentration, aspartate transaminase activity, and cholesterol, triglyceride, calcium, and phosphorus concentrations. Marked seasonal variation was observed in most parameters in conjunction with reproductive cycle, hibernation, or seasonal rainfall. Year-to-year differences and long-term alterations primarily reflected winter rainfall amounts. Site differences were minimal, and largely reflected geographic differences in precipitation patterns, such that results from these studies can be applied to other tortoise populations in environments with known rainfall and forage availability patterns.

Journal of Wildlife Diseases↗

Contaminant effect endpoints in terrestrial vertebrates at and above the individual level

Use of biochemical, physiological, anatomical, reproductive and behavioral characteristics of wild terrestrial vertebrates to assess contaminant exposure and effects has become commonplace over the past 3 decades. At the level of the individual organism, response patterns have been associated with and sometimes causally linked to contaminant exposure. However, such responses at the organismal level are rarely associated with or causally linked to effects at the population level. Although the ultimate goal of ecotoxicology is the protection of populations, communities, and ecosystems, most of the existing science and regulatory legislation focus on the level of the individual. Consequently, much of this overview concentrates on contaminant effects at the organismal level, with some extrapolation to higher-level effects. In this chapter, we review the state of the science for the evaluation of biotic end-points used to assess contaminant exposure and effects at or above the level of the individual. In addition, we describe extant contaminant concentration thresholds, guidelines, or standards (toxicant criteria) in environmental matrices (e.g., water, soil, sediment, foods) that have been developed to protect wild terrestrial vertebrates. Suggestions are provided to develop and embellish the use and value of such endpoints and criteria for extrapolation of effects to higher levels of biological organization. Increasing focus on populations, communities, and ecosystems is needed to develop biologically meaningful regulatory guidelines that will protect natural resources.

Book chapter↗