Assessing Individual and Population-Level Effects of Anticoagulant Rodenticides on Wildlife

Anticoagulant rodenticides have been detected in many species of wildlife worldwide. However, the origins, exposure pathways, and effects of this exposure are not well understood. To accurately characterize the risks to wildlife from rodenticide use, better information is needed regarding the proportion of populations being exposed, what proportion of individuals in populations are affected, and in what ways. The relationship between anticoagulant rodenticide concentrations found in wildlife and the rate of mortality or illness have been the subjects of much research. Residue levels observed in liver and whole-body analyses vary and overlap extensively among apparently healthy asymptomatic individuals and sublethal and lethal cases. Results from laboratory studies also show there can be wide variability in lethal and sublethal effects among and within taxonomic groups. Correlating the sublethal and reproductive effects observed in laboratory studies with realistic exposure scenarios and effects in the wild is needed to improve risk assessments. For species with limited numbers or declining populations, a critical question yet to be answered is if the rodenticide exposure documented in individual animals inhibits population growth or contributes to population declines by lowering survival and reproductive success. This information is essential to the regulatory agencies that must weigh the risks and benefits of rodenticide uses and identify restrictions that are effective in reducing risks to wildlife

Efficacy of Rodenticides for Roof Rat and Deer Mouse Control in Orchards

Roof rats and deer mice are occasional pests of orchard crops throughout the world. The application of rodenticides is an effective and practical method for controlling rodent pests and reducing damage. However, a paucity of information exists on the efficacy of rodenticides in orchards for these pest species. To address this gap in knowledge, we first developed an index to measure rodent activity in order to monitor efficacy of rodenticides. We then used this index to test the efficacy of 3 first-generation anticoagulant rodenticide baits to determine their utility for controlling roof rats and deer mice in agricultural orchards. Of the baits tested, the 0.005% diphacinone grain bait was the most effective option for controlling both roof rats and deer mice (average efficacy = 90% and 99%, respectively). The use of elevated bait stations proved effective at providing bait to target species and should substantially limit non-target access to rodenticides

A California Without Rodenticides: Challenges for Commensal Rodent Management in the Future

Rodenticides are an essential tool in the integrated pest management of infestations of commensal rodents (Rattus norvegicus, R. rattus, and Mus musculus). With the introduction of Assembly Bill 1788, the California Ecosystems Protection Act of 2019, California is potentially facing a future with new restrictions on the use of anticoagulant rodenticides to manage commensal rodents in urban areas. Assembly Bill 1788 has been proposed specifically to protect predators from anticoagulant rodenticide poisoning and seeks to restrict the application of second-generation anticoagulant rodenticides (SGARs) for use in many urban and non-urban areas of California, USA. Exclusion and cultural practices, such as landscape management and sanitation (i.e., cleaning of property including but not limited to trash containment and removal, and drain sanitation), remain important and successful tools for managing rodent populations. However, increased exposure of wildlife to anticoagulant rodenticides has been detected California. Several animal species have been documented as having succumbed to rodenticide toxicosis. When rodents are killed by SGARs and consumed by predators, SGAR residues have been detected in the livers of predatory species. However, the effects of chronic, sublethal exposure to predators are not well understood. We discuss the current and proposed changes to rodenticide legislation in California, impacts of rodenticide to wildlife, and the potential effects of restrictions on wildlife. We discuss limitations to rodent management programs that have historically replied on the use of SGARs and the potential impacts of the proposed legislation on communities across California. We also identify research gaps that are impeding the adoption of evidence-based best management strategies for rodent control. To improve the success of commensal rodent control programs in California, more research is needed to develop effective strategies for rodent management

Utility of Visual Counts for Determining Efficacy of Management Tools for California Ground Squirrels

Visual counts are frequently used to assess efficacy of management tools for ground squirrels (Marmotini), but the effectiveness of this approach has not been assessed for many ground squirrel species including California ground squirrels (Otospermophilus spp.). As such, we used visual counts of California ground squirrels to determine the efficacy of diphacinone-treated oat groat applications in rangelands in central California, USA, and compared those results to efficacy values derived from the use of radio-collared ground squirrels in the same plots. We also used location data of radio-collared ground squirrels to explore the size of buffer zone needed around census plots to provide an accurate assessment of efficacy when using visual counts. We did not observe a difference in efficacy associated with the 2 monitoring strategies, indicating that visual counts are an effective monitoring tool for ground squirrels. We observed low efficacy in 2 treatment plots, likely due to low usage of those plots by ground squirrels. Increasing the size of buffer zones would increase the usage of treatment areas by the target population and would help to minimize reinvasion by adjacent ground squirrel populations, which could bias efficacy values low. We suggest a minimum of a 61-m buffer surrounding census plots. Increasing to 66 m or more would further benefit efficacy assessments, but increased size of the buffer zone must be balanced with greater costs and regulatory constraints

Do Trap-Neuter-Return (TNR) Practices Contribute to Human–Coyote Conflicts in Southern California?

One possible contributor to the unusually high number of conflicts between coyotes (Canis latrans) and people in urban southern California, USA, may be the abundance of free-roaming domestic cats (Felis catus; cats) subsidized by feeding and augmented by trap-neuter-return (TNR) programs. To determine if coyotes regularly prey on and consume cats, we combined visual and molecular-genetic approaches to identify prey items in stomachs of 311 coyotes from Los Angeles County and Orange County, provided to the South Coast Research and Extension Center, in Irvine, California, between June 2015 and December 2018. We detected cat remains in 35% of the stomachs of 245 coyotes with identifiable meals, making cats the most common mammalian prey item consumed and more common than reported previously. Using a geographic information systems approach, we then compared landscape characteristics associated with locations of coyotes that ate cats to public shelter records for TNR cat colonies. Cat-eating coyotes were associated with areas that were more intensively developed, had little natural or altered open space, and had higher building densities than coyotes that did not eat cats. Locations of TNR colonies had similar landscape characteristics. Coyotes associated with TNR colonies, and those that were euthanized (vs. road-killed), were also more likely to have consumed cats. The high frequency of cat remains in coyote diets and landscape characteristics associated with TNR colonies and cat-eating coyotes support the argument that high cat densities and associated supplemental feeding attracted coyotes. Effective mitigation of human–coyote conflicts may require prohibitions on outdoor feeding of free-roaming cats and wildlife and the elimination of TNR colonies

Flea‘in Around: A Look at the Identification, Preservation, Clearing, and Mounting of Siphonaptera

Fleas are remarkable and highly specialized insects, with no part of their external anatomy being easily mistaken for that of any other insect. Due to their small size, the subtle differences among the distinguishing morphological characteristics of each species, and complexities of preparing specimens, identifying, and working with fleas is challenging. Various documents and taxonomic keys are available that discuss mounting procedures and the identification of medically important fleas for large regions of the world including the United States; however, many of these have become antiquated over time. Some of the distinguishing specialized characteristics exhibited among flea species, as presented in older keys, come in the form of line drawings, which are accurate but can be difficult to use when comparing it to structures on a whole specimen when viewed through a microscope. This paper presents a guide which describes in detail previously developed, but obscure techniques covering the preservation, preparation, clearing, and mounting of Siphonaptera specimens. In addition, we are also presenting an easy-to-use photographic key of twelve flea species collected from back yard wildlife, as well as pet cats and dogs in Orange County, CA. This key, which is freely available online at the Orange County Mosquito and Vector Control District’s website, is an effective tool for the identification of common flea species found in southern California. Using the key in conjunction with the mounting guide will provide users with a full-circle guide to preserving, identifying, and mounting flea specimens. Keyed flea genera include Cediopsylla, Ctenocephalides, Diamanus, Echidinophaga, Hoplopsyllus, Leptopsylla, Nosopsyllus, Orchopoeas, Pulex, and Xenopsylla. Examined hosts include cats, coyotes, dogs, mice, opossums, rabbits, raccoons, rats, skunks, squirrels, and woodrats

Protein Kinase D1 Modulates Aldosterone-Induced ENaC Activity in a Renal Cortical Collecting Duct Cell Line

Aldosterone treatment of M1-CCD cells stimulated an increase in epithelial Na+ channel (ENaC) alpha-subunit expression that was mainly localized to the apical membrane. PKD1 suppressed cells constitutively expressed ENaC alpha at low abundance, with no increase after aldosterone treatment. Here ENaC alpha was mainly localized proximal to the basolateral surface of the epithelium both before and after aldosterone treatment. Apical membrane insertion of ENaC beta in response to aldosterone treatment was also sensitive to PKD1 suppression as was the aldosterone-induced rise in the amiloride-sensitive, trans-epithelial current (ITE). The interaction of the mineralocorticoid receptor (MR) with specific elements in the promoters of aldosterone responsive genes is stabilized by ligand interaction and phosphorylation. PKD1 suppression inhibited aldosterone-induced SGK-1 expression. The nuclear localization of MR was also blocked by PKD1 suppression and MEK antagonism implicating both these kinases in MR nuclear stabilization. PKD1 thus modulates aldosterone-induced ENaC activity through the modulation of sub-cellular trafficking and the stabilization of MR nuclear localization

A time-lagged association between the gut microbiome, nestling weight and nestling survival in wild great tits

Natal body mass is a key predictor of viability and fitness in many animals. While variation in body mass and therefore juvenile viability may be explained by genetic and environmental factors, emerging evidence points to the gut microbiota as an important factor influencing host health. The gut microbiota is known to change during development, but it remains unclear whether the microbiome predicts fitness, and if it does, at which developmental stage it affects fitness traits. We collected data on two traits associated with fitness in wild nestling great tits Parus major: weight and survival to fledging. We characterised the gut microbiome using 16S rRNA sequencing from nestling faeces and investigated temporal associations between the gut microbiome and fitness traits across development at Day-8 (D8) and Day-15 (D15) post-hatching. We also explored whether particular microbial taxa were ‘indicator species’ that reflected whether nestlings survived or not. There was no link between mass and microbial diversity on D8 or D15. However, we detected a time-lagged relationship where weight at D15 was negatively associated with the microbial diversity at D8, controlling for weight at D8, therefore reflecting relative weight gain over the intervening period. Indicator species analysis revealed that specificity values were high and fidelity values were low, suggesting that indicator taxa were primarily detected within either the survived or not survived groups, but not always detected in birds that either survived or died. Therefore these indicator taxa may be sufficient, but not necessary for determining either survival or mortality, perhaps owing to functional overlap in microbiota. We highlight that measuring microbiome-fitness relationships at just one time point may be misleading, especially early in life. Instead, microbial-host fitness effects may be best investigated longitudinally to detect critical development windows for key microbiota and host traits associated with neonatal weight. Our findings should inform future hypothesis testing to pinpoint which features of the gut microbial community impact on host fitness, and when during development this occurs. Such confirmatory research will shed light on population level processes and could have the potential to support conservation

Governing urban vacancy in post-crash Dublin: contested property and alternative social projects

© 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group. The scale and severity of property crashes following the global financial crisis has made vacancy a more visible and politically significant feature of cities. Although research has focused on urban experiments in vacant spaces, there has been less emphasis on how the contested property relations around vacancy remake urban governance. In this paper, we argue that debates about vacancy have been a central concern in post-crisis urban governance. In the first part of the paper we draw two conceptual approaches into a dialogue and apply them to an analysis of vacant space: that of Nicholas Blomley on property and Elizabeth Povinelli on “alternative social projects”. In the second part of the paper, we critically analyse how three groups discursively construct the need to “activate” and “re-use” vacant spaces in Dublin: grassroots groups, urban policy-makers, and financial actors. We argue that governing vacancy will be a key feature of post-crisis urbanisation

European Stroke Organisation and European Academy of Neurology joint guidelines on post-stroke cognitive impairment.

The optimal management of post-stroke cognitive impairment remains controversial. These joint European Stroke Organisation (ESO) and European Academy of Neurology (EAN) guidelines provide evidence-based recommendations to assist clinicians in decision making around prevention, diagnosis, treatment and prognosis. These guidelines were developed according to ESO standard operating procedure and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. The working group identified relevant clinical questions, performed systematic reviews and, where possible, meta-analyses of the literature, assessed the quality of the available evidence and made specific recommendations. Expert consensus statements were provided where insufficient evidence was available to provide recommendations based on the GRADE approach. There was limited randomised controlled trial evidence regarding single or multicomponent interventions to prevent post-stroke cognitive decline. Interventions to improve lifestyle and treat vascular risk factors may have many health benefits but a beneficial effect on cognition is not proven. We found no evidence around routine cognitive screening following stroke but recognise the importance of targeted cognitive assessment. We described the accuracy of various cognitive screening tests but found no clearly superior approach to testing. There was insufficient evidence to make a recommendation for use of cholinesterase inhibitors, memantine nootropics or cognitive rehabilitation. There was limited evidence on the use of prediction tools for post-stroke cognitive syndromes (cognitive impairment, dementia and delirium). The association between post-stroke cognitive impairment and most acute structural brain imaging features was unclear, although the presence of substantial white matter hyperintensities of presumed vascular origin on acute MRI brain may help predict cognitive outcomes. These guidelines have highlighted fundamental areas where robust evidence is lacking. Further, definitive randomised controlled trials are needed, and we suggest priority areas for future research