Coyote removal: can the short-term application of a controversial management tool improve female greater sage-grouse survival or nest success?

Greater sage-grouse Centrocercus urophasianus have declined across western North America, intensifying the need for ecological research that enhances management and conservation goals. Predator–prey interactions can have widespread ecological effects but there is a paucity of information about predator effects on sage-grouse ecology. During a two-year study from 2011–2012, we modified the existing framework designed for predator management to test the effects of coyote Canis latrans removal on female sage-grouse survival and nest success in the Bighorn Basin of Wyoming, USA, where coyotes were found to be the dominant predator. We used VHF radio-telemetry to monitor female survival and locate nests over pre-treatment and treatment breeding seasons, and for one-year post-treatment to the next breeding season. During treatment, we manipulated predator management at three sites to have targeted, non-targeted, and no coyote removal. Female survival remained constant over the nesting period when treatment was applied, and there were little differences between one-year pre- (Š = 0.64, 90% CI = 0.38, 0.90) and one-year post-treatment survival estimates (Š = 0.71, 90% CI = 0.55, 0.87) at the targeted coyote removal site. No differences were detected in the daily survival rates of nests relative to coyote removal. We conclude removing coyotes, the primary predator of nests and adult females identified within this system, did not improve female survival or nest success. However, long-term monitoring is recommended to provide a more robust understanding of this complex relationship

The Yersinia pestis Effector YopM Inhibits Pyrin Inflammasome Activation

Type III secretion systems (T3SS) are central virulence factors for many pathogenic Gram-negative bacteria, and secreted T3SS effectors can block key aspects of host cell signaling. To counter this, innate immune responses can also sense some T3SS components to initiate anti-bacterial mechanisms. The Yersinia pestis T3SS is particularly effective and sophisticated in manipulating the production of pro-inflammatory cytokines IL-1beta and IL-18, which are typically processed into their mature forms by active caspase-1 following inflammasome formation. Some effectors, like Y. pestis YopM, may block inflammasome activation. Here we show that YopM prevents Y. pestis induced activation of the Pyrin inflammasome induced by the RhoA-inhibiting effector YopE, which is a GTPase activating protein. YopM blocks YopE-induced Pyrin-mediated caspase-1 dependent IL-1beta/IL-18 production and cell death. We also detected YopM in a complex with Pyrin and kinases RSK1 and PKN1, putative negative regulators of Pyrin. In contrast to wild-type mice, Pyrin deficient mice were also highly susceptible to an attenuated Y. pestis strain lacking YopM, emphasizing the importance of inhibition of Pyrin in vivo. A complex interplay between the Y. pestis T3SS and IL-1beta/IL-18 production is evident, involving at least four inflammasome pathways. The secreted effector YopJ triggers caspase-8- dependent IL-1beta activation, even when YopM is present. Additionally, the presence of the T3SS needle/translocon activates NLRP3 and NLRC4-dependent IL-1beta generation, which is blocked by YopK, but not by YopM. Taken together, the data suggest YopM specificity for obstructing the Pyrin pathway, as the effector does not appear to block Y. pestis-induced NLRP3, NLRC4 or caspase-8 dependent caspase-1 processing. Thus, we identify Y. pestis YopM as a microbial inhibitor of the Pyrin inflammasome. The fact that so many of the Y. pestis T3SS components are participating in regulation of IL-1beta/IL-18 release suggests that these effects are essential for maximal control of innate immunity during plague

A Glutathione Peroxidase, Intracellular Peptidases and the TOR Complexes Regulate Peptide Transporter PEPT-1 in C. elegans

The intestinal peptide transporter PEPT-1 in Caenorhabditis elegans is a rheogenic H+-dependent carrier responsible for the absorption of di- and tripeptides. Transporter-deficient pept-1(lg601) worms are characterized by impairments in growth, development and reproduction and develop a severe obesity like phenotype. The transport function of PEPT-1 as well as the influx of free fatty acids was shown to be dependent on the membrane potential and on the intracellular pH homeostasis, both of which are regulated by the sodium-proton exchanger NHX-2. Since many membrane proteins commonly function as complexes, there could be proteins that possibly modulate PEPT-1 expression and function. A systematic RNAi screening of 162 genes that are exclusively expressed in the intestine combined with a functional transport assay revealed four genes with homologues existing in mammals as predicted PEPT-1 modulators. While silencing of a glutathione peroxidase surprisingly caused an increase in PEPT-1 transport function, silencing of the ER to Golgi cargo transport protein and of two cytosolic peptidases reduced PEPT-1 transport activity and this even corresponded with lower PEPT-1 protein levels. These modifications of PEPT-1 function by gene silencing of homologous genes were also found to be conserved in the human epithelial cell line Caco-2/TC7 cells. Peptidase inhibition, amino acid supplementation and RNAi silencing of targets of rapamycin (TOR) components in C. elegans supports evidence that intracellular peptide hydrolysis and amino acid concentration are a part of a sensing system that controls PEPT-1 expression and function and that involves the TOR complexes TORC1 and TORC2

Coyote removal: can the short-term application of a controversial management tool improve female greater sage-grouse survival or nest success?

Greater sage-grouse Centrocercus urophasianus have declined across western North America, intensifying the need for ecological research that enhances management and conservation goals. Predator–prey interactions can have widespread ecological effects but there is a paucity of information about predator effects on sage-grouse ecology. During a two-year study from 2011–2012, we modified the existing framework designed for predator management to test the effects of coyote Canis latrans removal on female sage-grouse survival and nest success in the Bighorn Basin of Wyoming, USA, where coyotes were found to be the dominant predator. We used VHF radio-telemetry to monitor female survival and locate nests over pre-treatment and treatment breeding seasons, and for one-year post-treatment to the next breeding season. During treatment, we manipulated predator management at three sites to have targeted, non-targeted, and no coyote removal. Female survival remained constant over the nesting period when treatment was applied, and there were little differences between one-year pre- (Š = 0.64, 90% CI = 0.38, 0.90) and one-year post-treatment survival estimates (Š = 0.71, 90% CI = 0.55, 0.87) at the targeted coyote removal site. No differences were detected in the daily survival rates of nests relative to coyote removal. We conclude removing coyotes, the primary predator of nests and adult females identified within this system, did not improve female survival or nest success. However, long-term monitoring is recommended to provide a more robust understanding of this complex relationship

Molecular forensics in avian conservation: a DNA‑based approach for identifying mammalian predators of ground‑nesting birds and eggs

Background: The greater sage-grouse (Centrocercus urophasianus) is a ground-nesting bird from the Northern Rocky Mountains and a species at risk of extinction in in multiple U.S. states and Canada. Herein we report results from a proof of concept that mitochondrial and nuclear DNAs from mammalian predator saliva could be non-invasively collected from depredated greater sage-grouse eggshells and carcasses and used for predator species identification. Molecular forensic approaches have been applied to identify predators from depredated remains as one strategy to better understand predator–prey dynamics and guide management strategies. This can aid conservation efforts by correctly identifying predators most likely to impact threatened and endangered species. DNA isolated from noninvasive samples around nesting sites (e.g. fecal or hair samples) is one method that can increase the success and accuracy of predator species identification when compared to relying on nest remains alone. Results: Predator saliva DNA was collected from depredated eggshells and carcasses using swabs. We sequenced two partial fragments of two mitochondrial genes and obtained microsatellite genotypes using canid specific primers for species and individual identification, respectively. Using this multilocus approach we were able to identify predators, at least down to family, from 11 out of 14 nests (79 %) and three out of seven carcasses (47 %). Predators detected most frequently were canids (86 %), while other taxa included rodents, a striped skunk, and cattle. We attempted to match the genotypes of individual coyotes obtained from eggshells and carcasses with those obtained from fecal samples and coyotes collected in the areas, but no genotype matches were found. Conclusion: Predation is a main cause of nest failure in ground-nesting birds and can impact reproduction and recruitment. To inform predator management for ground-nesting bird conservation, accurate identification of predator species is necessary. Considering predation can have a high impact on recruitment, predation events are very difficult to observe, and predator species are difficult to identify visually from nest remains, molecular approaches that reduce the need to observe or handle animals offer an additional tool to better understand predator–prey dynamics at nesting sites

Impacts of coyote removal on space use by greater sage-grouse

Greater sage-grouse (Centrocercus urophasianus) are in decline across western North America. Identification of management strategies to enhance populations, such as predator management, may be needed to reduce further declines, but unintentional effects associated with increased human activity should also be considered. We evaluated the effect of 3 levels of predator management effort on greater sage-grouse space use. Home range size, movement rate, seasonal movement timing, and inter-seasonal distances traveled were examined as behavioral responses relative to levels of coyote removal in Bighorn Basin, Wyoming. We observed larger home range sizes during brood-rearing but overall smaller annual core (25% density kernel) sizes with higher levels of predator management. We observed higher movement rates, farther inter-seasonal distances traveled, and higher proportions of sage-grouse making inter-seasonal movements with increased predator removal effort. Our fi dings suggest activities like predator management may influence behavioral and spatial aspects of sage-grouse ecology. Management actions must consider the direct and indirect effects actions taken to improve a population’s growth will have on behavior, habitat use, and ultimately, long-term persistence

Greater Sage-Grouse Nest Survival in Northwestern Wyoming

Nest survival, along with female survival and chick survival, is the most important vital rates to population growth of greater sage-grouse (Centrocercus urophasianus; sage-grouse). We used global positioning system and very high-frequency transmitters on female sage-grouse to identify 204 nests and monitor incubation on 5 sites in the Bighorn Basin, Wyoming from 2011 to 2014; we determined nest fate and identified predators with camera traps. We used an information-theoretic approach to compare 6 a priori nest survival models. Nest survival was best described by a model that included differences across study sites and ranged from 0.20±0.01 (SE) to 0.56±0.05. Coyotes (Canis latrans) were the apex predator, and coyotes were removed annually by United States Department of Agriculture, Animal and Plant Inspection Service, Wildlife Services on 4 of 5 sites to reduce depredation to livestock and big game (removal = 0–0.56 coyotes/km2/site). Coyotes were the greatest contributor to nest failure, followed by common ravens (Corvus corax), abandonment, and female mortality. The direct effect of nest depredation by coyotes was greater than other reported sage-grouse studies, yet our nest survival rates were consistent with others reported throughout the species range. Coyote removal did not appear to have indirect effects, such as a mesopredator release, on nest survival. Nest survival was least on a site where coyotes and ravens depredated nests at nearly the same rate, and where ravens were observed nesting on infrastructure close to nesting sage-grouse