Hybridization,agency discretion,and implementation of the U.S. Endangered Species Act

The U.S. Endangered Species Act (ESA) requires that the “best available scientific and commercial data” be used to protect imperiled species from extinction and preserve biodiversity. However, it does not provide specific guidance on how to apply this mandate. Scientific data can be uncertain and controversial, particularly regarding species delineation and hybridization issues. The U.S. Fish and Wildlife Service (FWS) had an evolving hybrid policy to guide protection decisions for individuals of hybrid origin. Currently, this policy is in limbo because it resulted in several controversial conservation decisions in the past. Biologists from FWS must interpret and apply the best available science to their recommendations and likely use considerable discretion in making recommendations for what species to list, how to define those species, and how to recover them. We used semistructured interviews to collect data on FWS biologists’ use of discretion to make recommendations for listed species with hybridization issues. These biologists had a large amount of discretion to determine the best available science and how to interpret it but generally deferred to the scientific consensus on the taxonomic status of an organism. Respondents viewed hybridization primarily as a problem in the context of the ESA, although biologists who had experience with hybridization issues were more likely to describe it in more nuanced terms. Many interviewees expressed a desire to continue the current case‐by‐case approach for handling hybridization issues, but some wanted more guidance on procedures (i.e., a “flexible” hybrid policy). Field‐level information can provide critical insight into which policies are working (or not working) and why. The FWS biologists’ we interviewed had a high level of discretion, which greatly influenced ESA implementation, particularly in the context of hybridization.     

Using home range estimates to construct social networks for species with indirect behavioral interactions

Social network analysis has become a vital tool for studying patterns of individual interactions that influence a variety of processes in behavior, ecology, and evolution. Taxa in which interactions are indirect or whose social behaviors are difficult to observe directly are being excluded from this rapidly expanding field. Here, we introduce a method that uses a probabilistic and spatially implicit technique for delineating social interactions. Kernel density estimators (KDE) are nonparametric techniques that are often used in home range analyses and allow researchers studying social networks to generate interaction matrices based on shared space use. We explored the use of KDE analysis and the effects of altering KDE input parameters on social network metrics using data from a natural population of the spatially persistent forked fungus beetle, Bolitotherus cornutus.     

Prenatal diagnosis,prediction of outcome and in utero therapy of isolated congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) can be associated with genetic or structural anomalies with poor prognosis. In isolated cases, survival is dependent on the degree of lung hypoplasia and liver position. Cases should be referred in utero to tertiary care centers familiar with this condition both for prediction of outcome as well as timed delivery. The best validated prognostic indicator is the lung area to head circumference ratio. Ultrasound is used to measure the lung area of the index case, which is then expressed as a proportion of what is expected normally (observed/expected LHR). When O/E LHR is < 25% survival chances are < 15%. Prenatal intervention, aiming to stimulate lung growth, can be achieved by temporary fetal endoscopic tracheal occlusion (FETO). A balloon is percutaneously inserted into the trachea at 26–28 weeks, and reversal of occlusion is planned at 34 weeks. Growing experience has demonstrated the feasibility and safety of the technique with a survival rate of about 50%. The lung response to, and outcome after FETO, is dependent on pre-existing lung size as well gestational age at birth. Early data show that FETO does not increase morbidity in survivors, when compared to historical controls. Several trials are currently under design. Copyright © 2008 John Wiley & Sons, Ltd.     

Metal mobility during in situ chemical oxidation of TCE by KMnO4

The potential for trace-metal contamination of aquifers as a side effect of In Situ Chemical Oxidation (ISCO) of chlorinated solvent contamination by KMnO(4) is investigated with column experiments. The experiments investigate metal mobility during in situ chemical oxidation of TCE by KMnO(4) under conditions where pH, flow rate, KMnO(4), TCE, and trace-metal concentrations were controlled. During ISCO, the injection of MnO(4) creates oxidizing conditions, and acidity released by the reactions causes a tendency toward low pH in aquifers. In order to evaluate the role of pH buffering on metal mobility, duplicate columns were constructed, one packed with pure silica sand, and one with a mixture of silica sand and calcite. Aqueous solutions of TCE and KMnO(4) (with 1 mg/L Cu, Pb, Zn, Mo, Ni, and Cr(VI)) were allowed to mix at the inlet to the columns. After the completion of the experiments, samples of Mn oxide were removed from the columns and analyzed by analytical scanning and transmission electron microscopy. In order to relate the results of the laboratory experiments to field settings, the analyses of Mn-oxide samples from the lab experiments were compared to samples of Mn oxide collected from a field-scale chemical-oxidation experiment that were also analyzed by analytical electron microscopy as well as time-of-flight secondary-ion mass spectroscopy. The pH ranged from 2.40 in the silica sand column to 6.25 in the calcite-containing column. The data indicate that aqueous Mo, Pb, Cu and Ni concentrations are attenuated almost completely within the columns. In contrast, Zn concentrations are not significantly attenuated and Cr(VI) is transported conservatively. The results indicate that within the range 2.40 to 6.25, metal mobility is not affected by pH. Comparison of analyses of Mn-oxide from the lab and field demonstrate that a variety of metals are sequestered from solution by Mn oxide.     

Sublethal contaminant exposure alters behavior in a common insect: Important implications for trophic transfer

This study examined the effects of sub-lethal exposure of the ubiquitous pesticide malathion on the behavior of the model orthopteran species, the house cricket (Acheta domesticus). Increasing concentrations of malathion caused male crickets to increase periods of non-directional movement, such as twitching and grooming, directional movement, and to seek out shelter less. These are all behavioral alterations that may increase the cricket's chances of being preyed upon, and thus have the potential for serious ecological consequences through trophic transfer. This study also revealed that female crickets appeared to be less affected by malathion than their male conspecifics, indicating a potential sex-bias in both susceptibility and possible predator attack.