Indirect Effects and Traditional Trophic Cascades: a Test Involving Wolves, Coyotes, and Pronghorn

The traditional trophic cascades model is based on consumer - resource interactions at each link in a food chain. However, trophic-level interactions, such as mesocarnivore release resulting from intraguild predation, may also be important mediators of cascades. From September 2001 to August 2004, we used spatial and seasonal heterogeneity in wolf distribution and abundance in the southern Greater Yellowstone Ecosystem to evaluate whether mesopredator release of coyotes ( Canis latrans), resulting from the extirpation of wolves ( Canis lupus), accounts for high rates of coyote predation on pronghorn ( Antilocapra americana) fawns observed in some areas. Results of this ecological perturbation in wolf densities, coyote densities, and pronghorn neonatal survival at wolf-free and wolf-abundant sites support the existence of a species-level trophic cascade. That wolves precipitated a trophic cascade was evidenced by fawn survival rates that were four-fold higher at sites used by wolves. A negative correlation between coyote and wolf densities supports the hypothesis that interspecific interactions between the two species facilitated the difference in fawn survival. Whereas densities of resident coyotes were similar between wolf-free and wolf-abundant sites, the abundance of transient coyotes was significantly lower in areas used by wolves. Thus, differential effects of wolves on solitary coyotes may be an important mechanism by which wolves limit coyote densities. Our results support the hypothesis that mesopredator release of coyotes contributes to high rates of coyote predation on pronghorn fawns, and demonstrate the importance of alternative food web pathways in structuring the dynamics of terrestrial systems

Recolonizing wolves and mesopredator suppression of coyotes:impacts on pronghorn population dynamics

Food web theory predicts that the loss of large carnivores may contribute toelevated predation rates and, hence, declining prey populations, through the process ofmesopredator release. However, opportunities to test predictions of the mesopredator releasehypothesis are rare, and the extent to which changes in predation rates influence preypopulation dynamics may not be clear due to a lack of demographic information on the preypopulation of interest. We utilized spatial and seasonal heterogeneity in wolf distribution andabundance to evaluate whether mesopredator release of coyotes (Canis latrans), resulting fromthe extirpation of wolves (Canis lupus) throughout much of the United States, contributes tohigh rates of neonatal mortality in ungulates. To test this hypothesis, we contrasted causes ofmortality and survival rates of pronghorn (Antilocapra americana) neonates captured at wolf-free and wolf-abundant sites in western Wyoming, USA, between 2002 and 2004. We thenused these data to parameterize stochastic population models to heuristically assess the impactof wolves on pronghorn population dynamics due to changes in neonatal survival. Coyotepredation was the primary cause of mortality at all sites, but mortality due to coyotes was 34%lower in areas utilized by wolves (P , 0.001). Based on simulation modeling, the realizedpopulation growth rate was 0.92 based on fawn survival in the absence of wolves, and 1.06 atsites utilized by wolves. Thus, wolf restoration is predicted to shift the trajectory of thepronghorn population from a declining to an increasing trend. Our results suggest thatreintroductions of large carnivores may influence biodiversity through effects on preypopulations mediated by mesopredator suppression. In addition, our approach, whichcombines empirical data on the population of interest with information from other datasources, demonstrates the utility of using simulation modeling to more fully evaluateecological theories by moving beyond estimating changes in vital rates to analyses ofpopulation-level impacts

Protecting Migration Corridors: Challenges and Optimism for Mongolian Saiga

Hunting pressure and habitat loss place the endangered saiga, a type of antelope that was once abundant in central Asia, at high risk of extinction, and make the protection of the migratory routes of Mongolian populations even more critical for conserving the species

Capture of Ungulates in Central Asia Using Drive Nets: Advantages and Pitfalls Illustrated by the Endangered Mongolian Saiga Saiga Tatarica Mongolica

The study of mammals suffering intense poaching in remote areas poses an increasingly difficult conservation challenge, in part because the extreme flightiness of such species complicates safe capture. The benefits of handling (an opportunity to obtain biological information and attach radio collars) must be weighed against stress to the animals and potential capture-related mortality. In parts of Central Asia this problem is not trivial, as populations have been heavily harvested and opportunities for restraint are often limited. Mongolian saiga Saiga tatarica mongolica, being both Endangered and poached, typifies these issues. Here we describe capture protocols for adult females handled quickly and without anaesthesia. Using multiple vehicles driven at high speed, individual saiga were isolated from groups and herded into nets. Chase time was linearly associated with rectal temperature (P \u3c 0.03), with maximum pursuits and temperatures of 9 minutes and 43.1 degrees C, respectively; time to release averaged \u3c7 minutes. Given that rural residents often chase saiga and other desert and steppe-dwelling ungulates, for photography or for amusement, our results offer conservationists and government officials an empirical basis for recommending prudence on chase times and/or for recommending that the practice be prevented

Capture of ungulates in Central Asia using drive nets: advantages and pitfalls illustrated by the Endangered Mongolian saiga \u3ci\u3eSaiga tatarica mongolica\u3c/i\u3e

The study of mammals suffering intense poaching in remote areas poses an increasingly difficult conservation challenge, in part because the extreme flightiness of such species complicates safe capture. The benefits of handling (an opportunity to obtain biological information and attach radio collars) must be weighed against stress to the animals and potential capture-related mortality. In parts of Central Asia this problem is not trivial, as populations have been heavily harvested and opportunities for restraint are often limited. Mongolian saiga Saiga tatarica mongolica, being both Endangered and poached, typifies these issues. Here we describe capture protocols for adult females handled quickly and without anaesthesia. Using multiple vehicles driven at high speed, individual saiga were isolated from groups and herded into nets. Chase time was linearly associated with rectal temperature (P,0.03), with maximum pursuits and temperatures of 9 minutes and 43.1 degrees C, respectively; time to release averaged \u3c7 minutes. Given that rural residents often chase saiga and other desert and steppe-dwelling ungulates, for photography or for amusement, our results offer conservationists and government officials an empirical basis for recommending prudence on chase times and/or for recommending that the practice be prevented

Capture of ungulates in Central Asia using drive nets: advantages and pitfalls illustrated by the Endangered Mongolian saiga \u3ci\u3eSaiga tatarica mongolica\u3c/i\u3e

The study of mammals suffering intense poaching in remote areas poses an increasingly difficult conservation challenge, in part because the extreme flightiness of such species complicates safe capture. The benefits of handling (an opportunity to obtain biological information and attach radio collars) must be weighed against stress to the animals and potential capture-related mortality. In parts of Central Asia this problem is not trivial, as populations have been heavily harvested and opportunities for restraint are often limited. Mongolian saiga Saiga tatarica mongolica, being both Endangered and poached, typifies these issues. Here we describe capture protocols for adult females handled quickly and without anaesthesia. Using multiple vehicles driven at high speed, individual saiga were isolated from groups and herded into nets. Chase time was linearly associated with rectal temperature (P,0.03), with maximum pursuits and temperatures of 9 minutes and 43.1 degrees C, respectively; time to release averaged \u3c7 minutes. Given that rural residents often chase saiga and other desert and steppe-dwelling ungulates, for photography or for amusement, our results offer conservationists and government officials an empirical basis for recommending prudence on chase times and/or for recommending that the practice be prevented

Endosomal Phosphoinositides and Human Diseases

Phosphoinositides (PIs) are lipid second messengers implicated in signal transduction and membrane trafficking. Seven distinct PIs can be synthesized by phosphorylation of the inositol ring of phosphatidylinositol (PtdIns), and their metabolism is accurately regulated by PI kinases and phosphatases. Two of the PIs, PtdIns3P and PtdIns(3,5)P2, are present on intracellular endosomal compartments, and several studies suggest that they have a role in membrane remodeling and trafficking. We refer to them as ‘endosomal PIs’. An increasing number of human genetic diseases including myopathy and neuropathies are associated to mutations in enzymes regulating the turnover of these endosomal PIs. The PtdIns3P and PtdIns(3,5)P2 3-phosphatase myotubularin gene is mutated in X-linked centronuclear myopathy, whereas its homologs MTMR2 and MTMR13 and the PtdIns(3,5)P2 5-phosphatase SAC3/FIG4 are implicated in Charcot–Marie–Tooth peripheral neuropathies. Mutations in the gene encoding the PtdIns3P5-kinase PIP5K3/PIKfyve have been found in patients affected with François–Neetens fleck corneal dystrophy. This review presents the roles of the endosomal PIs and their regulators and proposes defects of membrane remodeling as a common pathological mechanism for the corresponding diseases

The Prevalence and Influence of the Combination of Humor and Violence in Super Bowl Commercials

The growing concern over violence in the media has led to vast amounts of research examining the effects of violent media on viewers. An important subset of this research looks at how humor affects this relationship. While research has considered this subset in television programming, almost no research has explored this in the context of advertising. This paper builds on the little research that exists by examining the effects of combining humor and violence, as well as the theoretical approaches that underlie these effects. A content analysis is conducted to identify the prevalence of violence, humor, and the combination of these elements in a longitudinal sample of Super Bowl commercials (2005, 2007, and 2009). Further, we investigate the relationship between the joint occurrence of humor and violence in ads and ad popularity. We conclude that violent acts are rampant in these commercials and that many acts are camouflaged by the simultaneous presence of humor, especially in the most popular ads

Synthesis, Purification and Crystallization of Guanine-rich RNA Oligonucleotides

Guanine-rich RNA oligonucleotides display many novel structural motifs in recent crystal structures. Here we describe the procedures of the chemical synthesis and the purification of such RNA molecules that are suitable for X-ray crystallographic studies. Modifications of the previous purification methods allow us to obtain better yields in shorter time. We also provide 24 screening conditions that are very effective in crystallization of the guanine-rich RNA oligonucleotides. Optimal crystallization conditions are usually achieved by adjustment of the concentration of the metal ions and pH of the buffer. Crystals obtained by this method usually diffract to high resolution

Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 $< p_{\rm{T}, assoc} < p_{\rm{T}, trig} <$ 5.0 GeV/$c$ is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range $|\eta|<0.9$. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161