Evidence for the Use of Vocalization to Coordinate the Killing of a White-Tailed Deer, Odocoileus virginianus, by Coyotes, Canis latrans

Among the social canids, howling is largely accepted as playing a role in territory maintenance. However, its role in communication within packs, such as announcing departures from den and rendezvous sites and coordinating reunions or movements, remains largely speculative. We report an observation where a radio-collared adult male Coyote (Canis latrans) and his mate seemed to summon two other Coyotes (presumed to be their offspring) from ~700 m away to join in the successful pursuit of an adult male White-tailed Deer (Odocoileus virginianus). Our observation suggests that Coyotes can use vocalization as an effective means of coordinating social activities such as the hunting of large prey

He-isotopic investigation of geothermal gases from the Tabar-Lihir-Tanga-Feni Arc and Rabaul, Papua New Guinea

In order to investigate the behavior of slab-derived volatiles in the subduction environment, helium isotope ratios have been measured in geothermal gases from the Tabar-Lihir-TangaFeni (TLTF) chain in the Bismarck Archipelago of Papua New Guinea. As recorded by several geochemical tracers, these volcanos carry an exceptionally large slab-derived component, and therefore may provide new insights to the old question of volatiles in subduction zones. Geothermal gases from Lihir Island have homogeneous ^3He/^4He ratios of 7.18±0.07 times the atmospheric ratio (R_A), while those from Ambitle Island (Feni Group) have lower ratios of 6.61±0.13 R_A. These ^3He/^4He ratios are within the range defined by more-typical arc volcanos, but lie at the low end of the spectrum observed in arc volcanos erupted through purely oceanic crust. Although a small slab-derived signature (^3He/^4He ratio lower than depleted mantle) exists in the TLTF gases, these data demonstrate that even in volcanos with a comparatively large slab component, He is overwhelmingly derived from the depleted mantle wedge. This observation further confirms the relative insensitivity of He isotopes to the presence of slab fluids. He isotope ratios of 6.25 R_A were measured in geothermal gases from the Rabaul Caldera on New Britain Island. Coincidentally, these samples were taken six months prior to the major 1994 eruption at Rabaul. In conjunction with samples taken from the same locality 8 years earlier, these data allow us to test whether increasing He isotope ratios associated with fresh ascending magmas precede volcanic eruptions. Although some of the 1986 samples had much lower ^3He/^4He ratios (5 R_A than observed in 1994, one did not. We thus find no strong evidence for a systematic rise in the He isotope ratio of the Rabaul fluids between 1986 and 1994. If a ^3He/^4He increase did precede the Rabaul eruption, then it occurred either prior to 1986 or sometime between our 1994 sampling and the eruption

Analysis of Canis mitochondrial DNA demonstrates high concordance between the control region and ATPase genes

BACKGROUND: Phylogenetic studies of wild Canis species have relied heavily on the mitochondrial DNA control region (mtDNA CR) to infer species relationships and evolutionary lineages. Previous analyses of the CR provided evidence for a North American evolved eastern wolf (C. lycaon), that is more closely related to red wolves (C. rufus) and coyotes (C. latrans) than grey wolves (C. lupus). Eastern wolf origins, however, continue to be questioned. Therefore, we analyzed mtDNA from 89 wolves and coyotes across North America and Eurasia at 347 base pairs (bp) of the CR and 1067 bp that included the ATPase6 and ATPase8 genes. Phylogenies and divergence estimates were used to clarify the evolutionary history of eastern wolves, and regional comparisons of nonsynonomous to synonomous substitutions (dN/dS) at the ATPase6 and ATPase8 genes were used to elucidate the potential role of selection in shaping mtDNA geographic distribution. RESULTS: We found high concordance across analyses between the mtDNA regions studied. Both had a high percentage of variable sites (CR = 14.6%; ATP = 9.7%) and both phylogenies clustered eastern wolf haplotypes monophyletically within a North American evolved lineage apart from coyotes. Divergence estimates suggest the putative red wolf sequence is more closely related to coyotes (D(xy)CR = 0.01982 ± 0.00494 SD; D(xy)ATP = 0.00332 ± 0.00097 SD) than the eastern wolf sequences (D(xy)CR = 0.03047 ± 0.00664 SD; D(xy)ATP = 0.00931 ± 0.00205 SD). Neutrality tests on both genes were indicative of the population expansion of coyotes across eastern North America, and dN/dS ratios suggest a possible role for purifying selection in the evolution of North American lineages. dN/dS ratios were higher in European evolved lineages from northern climates compared to North American evolved lineages from temperate regions, but these differences were not statistically significant. CONCLUSIONS: These results demonstrate high concordance between coding and non-coding regions of mtDNA, and provide further evidence that the eastern wolf possessed distinct mtDNA lineages prior to recent coyote introgression. Purifying selection may have influenced North American evolved Canis lineages, but detection of adaptive selection in response to climate is limited by the power of current statistical tests. Increased sampling and development of alternative analytical tools will be necessary to disentangle demographic history from processes of natural selection

A protected area influences genotype-specific survival and the structure of a Canis hybrid zone

It is widely recognized that protected areas can strongly influence ecological systems and that hybridization is an important conservation issue. However, previous studies have not explicitly considered the influence of protected areas on hybridization dynamics. Eastern wolves are a species of special concern and their distribution is largely restricted to a protected population in Algonquin Provincial Park (APP), Ontario, Canada, where they are the numerically dominant canid. We studied intrinsic and extrinsic factors influencing survival and cause-specific mortality of hybrid and parental canids in the three-species hybrid zone between eastern wolves, eastern coyotes, and gray wolves in and adjacent to APP. Mortality risk for eastern wolves in areas adjacent to APP was significantly higher than for other sympatric Canis types outside of APP, and for eastern wolves and other canids within APP. Outside of APP, the annual mortality rate of all canids by harvest (24%) was higher than for other causes of death (4–7%). Furthermore, eastern wolves (hazard ratio ¼ 3.5) and nonresidents (transients and dispersing animals, hazard ratio ¼ 2.7) were more likely to die from harvest relative to other Canis types and residents, respectively. Thus, eastern wolves dispersing from APP were especially vulnerable to harvest mortality. For residents, eastern wolf survival was more negatively influenced by increased road density than for other Canis types, further highlighting the sensitivity of eastern wolves to human disturbance. A cycle of dispersal from APP followed by high rates of mortality and hybridization appears to maintain eastern wolves at low density adjacent to APP, limiting the potential for expansion beyond the protected area. However, high survival and numerical dominance of eastern wolves within APP suggest that protected areas can allow rare hybridizing species to persist even if their demographic performance is compromised and barriers to hybridization are largely absent in the adjacent matrix

Population Estimate for the Bluenose-East Caribou Herd Using Post-calving Photography

Genetic and spatial analyses suggest that what was previously described as the Bluenose herd of barren-ground caribou (Rangifer tarandus groenlandicus) comprises three separate populations. Of these, the Bluenose-East caribou herd (BECH) has received little coverage in past surveys. Existing estimates of abundance suggested that current harvest rates of Bluenose-East caribou (~5000 animals/year) might be excessive. We used post-calving photography in June-July 2000 to estimate the size of the BECH. A maximum of 33 radio-collared caribou were available for location in June 2000. We located 30 of these caribou and photographed distinct groups containing 23 collared individuals. Excluding caribou assumed to belong to the neighboring Bluenose-West herd, we photographed a minimum of 84 412 adult and 4193 calf caribou. Using a simple mark-recapture model to account for caribou associated with collared individuals not photographed, we calculated an estimate of 104 000 ± 22 100 (95% CI 84 412 - 126 100) non-calf caribou. A recently published stochastic model produced a considerably higher and more variable estimate of 208 700 (95% CI 112 600 - 474 700). In March 2001, we deployed seven more radio collars in anticipation of repeating the census in 2001, but poor weather conditions precluded the formation of large aggregations. Present densities of Bluenose-East caribou seem high, and we recommend regular monitoring of body condition to assess the potential for a forage-induced population crash.Des analyses génétiques et spatiales suggèrent que ce que l'on a décrit précédemment comme le troupeau de caribous des toundras Bluenose (Rangifer tarandus groenlandicus) est en fait composé de trois populations distinctes. De ces trois hardes, le troupeau de caribous Bluenose de l'Est (TCBE) n'a pas reçu beaucoup d'attention au cours des relevés antérieurs. Les estimations d'abondance qui existent ont suggéré que le taux de prélèvement actuel de ce caribou (~ 5000 animaux/an) pourrait être excessif. On a eu recours à des clichés pris immédiatement après la mise bas en juin-juillet 2000 pour évaluer la taille du TCBE. En juin 2000, un maximum de 33 caribous munis de colliers émetteurs étaient disponibles pour la localisation. On en a repéré 30 et on a photographié des groupes distincts contenant 23 individus équipés de colliers émetteurs. Si l'on exclut les caribous qui feraient partie de la harde voisine Bluenose de l'Ouest, on a photographié un minimum de 84 412 adultes et 4193 veaux. En utilisant un simple modèle de marquage-recapture pour tenir compte des caribous reliés aux individus munis de colliers émetteurs non photographiés, on en arrive à une estimation du nombre de caribous excluant les veaux de 104 000 ± 22 100 (intervalle de confiance de 95 %: 84 412 - 126 000). Un modèle probabiliste publié récemment a donné une estimation nettement plus élevée et plus variable de 208 700 (intervalle de confiance de 95 %: 112 600 - 474 700). En mars 2001, on a eu recours à sept colliers émetteurs supplémentaires en prévision d'une reprise du recensement en 2001, mais le mauvais temps a empêché la formation de grands regroupements. Les densités actuelles du caribou Bluenose de l'Est semblent élevées, et on recommande une surveillance continue de l'état corporel afin d'évaluer le potentiel d'un effondrement de la population dû à un manque de fourrage

Sea Ice and Migration of the Dolphin and Union Caribou Herd in the Canadian Arctic: An Uncertain Future

Caribou (Rangifer tarandus groenlandicus × pearyi) of the Dolphin and Union herd migrate across the sea ice between Victoria Island and the adjacent Canadian Arctic mainland twice each year, southward in fall–early winter and northward in late winter–spring. As a result of warmer temperatures, sea ice between Victoria Island and the mainland now forms 8–10 days later than it did in 1982, raising questions about the impact of delayed ice formation on the ecology of the herd. We examined movements of female Dolphin and Union caribou as they relate to sea-ice crossings using four satellite collar datasets (46 caribou) obtained between 1987 and 2006. Since the late 1980s, Dolphin and Union caribou have been moving by early October to the southern coast of Victoria Island, where they stage until sea-ice formation allows migration across the sea ice to winter range on the mainland. Caribou spending the summer farther north on Victoria Island arrive later at the coast, which shortens their time spent on the staging area. During the study period, the collared caribou began crossings as soon as sea-ice formation allowed. Most caribou departed from just a few areas and tended to use the same departure areas each year. Highest mortality occurred during the fall–early winter ice crossing and in mid to late winter. Our research raises the question of how the Dolphin and Union caribou will persist in supporting harvesting if the crossing becomes riskier for them or if the seasonal migrations between Victoria Island and the mainland are interrupted.Les caribous (Rangifer tarandus groenlandicus × pearyi) du troupeau Dolphin-et-Union migrent en passant sur la glace de mer entre l’île Victoria et la partie continentale adjacente de l’Arctique canadien deux fois par année, se dirigeant vers le sud à l’automne et au début de l’hiver, et vers le nord à la fin de l’hiver et au printemps. En raison des températures plus chaudes, la glace de mer entre l’île Victoria et la partie continentale se forme maintenant de huit à dix jours plus tard qu’en 1982, ce qui a pour effet de soulever des questions sur les incidences de la formation tardive de la glace sur l’écologie du troupeau. Nous avons examiné les mouvements des caribous femelles de Dolphin-et-Union pendant qu’elles traversaient la glace de mer à l’aide de quatre ensembles de données obtenus par colliers-satellites (46 caribous) entre 1987 et 2006. Depuis la fin des années 1980, les caribous de Dolphin-et-Union se déplacent vers le début d’octobre vers la côte sud de l’île Victoria, où ils transitent jusqu’à ce que la formation de la glace permette la migration pour passer l’hiver sur la partie continentale. Les caribous qui passent l’été plus au nord sur l’île Victoria arrivent à la côte plus tard, ce qui a pour effet de raccourcir le temps qu’ils passent en halte migratoire. Au cours de la période visée par l’étude, les caribous dotés d’un collier commençaient à traverser dès que la formation de la glace le permettait. La plupart des caribous partaient de quelques endroits et avaient tendance à partir des mêmes endroits d’une année à l’autre. Le taux de mortalité était le plus élevé pendant les traversées de l’automne et du début de l’hiver, ainsi que vers le milieu et la fin de l’hiver. Notre étude soulève la question à savoir comment les caribous de Dolphin-et-Union vont réussir à soutenir la chasse si les traversées deviennent de plus en plus risquées pour eux ou si les migrations saisonnières entre l’île Victoria et la partie continentale sont interrompues

Resource selection at homesites by wolves and eastern coyotes in a \u3ci\u3eCanis\u3c/i\u3e hybrid zone

We modeled resource selection by wolves (Canis spp.), eastern coyotes (C. latrans), and admixed canids during the pup-rearing season at den and rendezvous sites (collectively, homesites) within a largely unprotected landscape proposed as the recovery zone for federally and provincially threatened eastern wolves (C. lycaon) in Ontario, Canada. Overall, canids selected wetlands, while avoiding secondary roads and open-structure rock-grass habitat patches. Packs with greater wolf ancestry selected wetlands and tertiary roads more strongly, while avoiding mixed conifer-hardwood forests. Contrary to our prediction, canids with greater coyote ancestry did not establish homesites closer to roads, which likely mitigated their risk of human-caused mortality during pup-rearing. Packs exhibited increased selection of wetlands within territories as a function of increasing availability of wetlands. Packs with abundant access to wetlands may prioritize this habitat type to exploit beavers, a valuable prey species during pup-rearing. Packs with higher pup survival selected hardwood forests and avoided conifer forests more than packs with lower pup survival. This is consistent with our understanding of habitat relations of the main prey species for canids in central Ontario and suggests that selecting prey-rich habitat types at homesites increases fitness. A proposed goal of eastern wolf recovery is numerical and geographical expansion outside of the population core in Algonquin Provincial Park. Thus, our results provide valuable information for conservation by quantifying resource selection of wolves, coyotes, and hybrids during pup-rearing and identifying links between fitness and homesite selection

Quantifying The Predator-Prey Relationship: Lessons Learned From A Multiple-Prey, Wolf-Hybrid Zone In Algonquin Park, Ontario, Canada

We studied winter kill rates and prey selection in an eastern wolf/moose/white-tailed deer system in Algonquin Park, Ontario Canada. Eastern wolves (Canis lycaon) are a distinct species, known to hybridize with both gray wolves and eastern coyotes, resulting in genetic variation within the study area. Deer in Algonquin are seasonally migratory, and accessibility of deer shifts significantly over winter. Some wolf packs migrate off territory to forage on deer, while others remain on territory, relying on moose. Our objectives were to 1) identify factors influencing variation in prey use, and 2) compare methodologies for quantifying prey use in a multiple prey system. We used fine scale GPS collar data to identify kill sites, and calculated relative use of moose and deer for each pack using several measures, including prey biomass/wolf/day, days/kill/pack and a newly developed method of time spent at kill sites from GPS data. We also conducted stable isotope analysis to compare with field collected prey-use data. Variation in prey use among wolf packs was most influenced by accessibility to deer, vulnerability of moose, and genetic admixture, and mediated by winter progression. Methodological comparisons showed that prey biomass/wolf/day tended to overestimate large prey items, while days/kill/pack overestimated the importance of small prey. Stable isotope results were inconsistent, revealing some possible weaknesses of this approach. We found wide variation in kill rates and relative prey use with winter progression, and spatial variation in age-specific predation associated with differences in hunter harvest pressure

PEGASUS: A multi-megawatt nuclear electric propulsion system

A propulsion system (PEGASUS) consisting of an electric thruster driven by a multimegawatt nuclear power system is proposed for a manned Mars mission. Magnetoplasmadynamic and mercury-ion thrusters are considered, based on a mission profile containing a 510-day burn time (for a mission time of approximately 1000 days). Both thrusters are capable of meeting the mission parameters. Electric propulsion systems have significant advantages over chemical systems, because of high specific impulse, lower propellant requirements, and lower system mass. The power for the PEGASUS system is supplied by a boiling liquid-metal fast reactor. The power system consists of the reactor, reactor shielding, power conditioning subsystems, and heat rejection subsystems. It is capable of providing a maximum of 8.5 megawatts of electrical power of which 6 megawatts is needed for the thruster system, leaving 1.5 megawatts available for inflight mission applications