234 research outputs found
Habitat Correlates of Jaguar Kill-Sites of Cattle in Northeastern Sonora, Mexico
Predation on cattle by the endangered jaguar (Panthera onca) can be a serious ecological and economic conflict. We investigated habitat characteristics of kill sites of cattle in Sonora, Mexico, from 1999 to 2004 to see whether habitat management or cattle distribution could be used as effective nonlethal methods to limit predation. Kill-sites were positively associated with oak, semitropical thornscrub, and xeric thornscrub vegetation types, whereas they were negatively associated with upland mesquite. Sites of cattle kills were also positively associated with proximity to permanent water sources and roads. A model including these relationships fi t kill locations well (AUC = 0.933) and correctly classified 93% of all kill-site locations. Because kill-sites were associated with specific habitat attributes, management practices that alter cattle distribution, such as placement of permanent water sources in uplands, herding, and fencing riparian areas characterized by frequent depredations, can be used to minimize co-occurrence of jaguars and cattle and, thus, potentially limit predation without illegal killing of jaguars. These practices could also lead to more uniform use of pastures and, consequently, higher stocking rates, resulting in increased profitability to landowners. Managing habitat attributes that predispose cattle to predation may provide a viable alternative for maintaining both livestock enterprises and a large endangered carnivore in areas of conflict
Condition, Survival, and Productivity of Mule Deer in Semiarid Grassland-Woodland in East-Central New Mexico
Mule deer (Odocoileus hemionus) are an economically important species to wildlife enterprises throughout New Mexico and the western United States, but populations are declining, limiting recreational and revenue potential to private and public wildlife managers. We documented body condition, survival, production of fawns, and trends in population size of a declining mule deer population on the Corona Range and Livestock Research Center (CRLRC), a multiple-use research ranch in east-central New Mexico owned by New Mexico State University. Mule deer females were in poor condition, characterized by accrual of little body fat or lean tissue (muscle mass) reserves. Annual female survival was 0.42, 0.78, and 0.71 during 2006 to 2008 and was related to poor body condition and precipitation. Survival of females was positively related to precipitation from January to June and April to June, seasons that coincide with conception-parturition and late gestation in deer. Survival also was positively related to increasing lean tissue (muscle) reserves. Malnutrition was the most common cause of death for adult females (n = 13 of 22). Fawn survival to weaning was positively related to increasing size of females, but not to any measure of seasonal or annual precipitation. Low survival and low productivity resulted in the CRLRC deer population declining from 539 to 191 during 2005 to 2008. Poor condition of deer was the result of both seasonal drought and a lack of quality forage. While drought will always decrease productivity of mule deer populations, survival may be maintained by managing for more drought-tolerant forage, which limit population declines during droughts
Factors Affecting Pregnancy in Free-ranging Elk, Cervus elaphus nelsoni, in Michigan
Uncertainty exists as to which factors are most closely related to probability of pregnancy in Elk (Cervus elaphus), which thresholds are key for managers who want to assess the potential productivity of free-ranging Elk herds, and whether these thresholds vary among populations. We examined relationships among pregnancy, age, and mass for 513 harvested free-ranging Elk in Michigan, and compared relationships with other published models and with thresholds derived from other free-ranging and penned populations to see if relationships were consistent among populations. Pregnancy rates varied (chi22 = 136.3; P < 0.0001) among yearling (0.30), prime-aged (2.5-11.5-year-olds; 0.88), and old (> 12.5-year-olds; 0.60) cows. Probability of pregnancy in adult cows was related to mass (chi2 = 7.4; P = 0.006), age (chi2 = 12.6; P = 0.0004) and age class (chi2 = 16.4; P < 0.0001), but not to lactation status (chi2 = 0.4; P = 0.515); pregnancy was also positively related (chi2 = 15.8; P < 0.0001) to mass in yearlings. Probability of pregnancy increased 1.02× and 1.04× for each 1 kg increase in body mass of adult and yearling cows, respectively, and prime-aged cows were 4.9× more likely to conceive than old cows. Compared to thresholds derived primarily from penned or farmed Elk, both adult and yearling free-ranging Elk in Michigan and elsewhere were able to achieve higher levels of pregnancy at lower body mass. Thresholds also varied among free-ranging Elk populations. Given variation among populations, managers should calibrate mass-pregnancy relationships for their respective populations to determine whether condition is potentially limiting pregnancy in their populations
Seroprevalence to and influence of exposure to bovine reproductive disease causative agents on pregnancy and preweaning calf survival of elk (Artiodactyla: Cervidae)
Success of recent introductions of elk (Cervus elaphus Linnaeus, 1758) in Mexico partly depends upon elk livestock interactions and conflicts. Disease can impact reproduction of elk and cattle, but is seldom considered in wild ruminants when reproductive output declines. We surveyed serological exposure of elk to causative agents in a bovine abortion profile (i.e., agents of brucellosis, leptospirosis, infectious bovine rhinotracheitis (IBR), bovine viral diarrhea, and neosporosis), as these diseases can negatively affect reproduction of cattle and elk, which frequently co-occur. We determined seroprevalence of exposure to these agents and used hierarchical logistic regression to model both pregnancy and lactation status (a surrogate for calf survival to weaning) as a function of population and exposure to disease causative agents. Tested elk populations were exposed to 2–4 of the agents except for Brucella abortus, which was not present. Pregnancy varied by population (P < 0.016) but not by exposure to any agent (P > 0.213). Proportion of females lactating in autumn did not vary among populations (P > 0.247) nor by exposure to any agent (P > 0.281). Exposure did not affect productivity of elk, despite exposure levels reflective of previous surveys throughout North America and low pregnancy and calf survival in some populations. Because all surveyed elk populations showed exposure to bovine herpesvirus-1 (BHV-1), IBR would be the most likely disease to be introduced with elk, although risk is low given high seroprevalence to BHV-1 among cattle in Mexico. Conversely, brucellosis is endemic in Mexico and can significantly impact productivity of elk. Thus, contracting brucellosis from cattle is the highest disease-related threat to elk introductions or translocation in Mexico.Una parte del éxito de las reintroducciones de ciervo wapità (C. elaphus) en México depende de las interacciones y posibles conflictos con el ganado doméstico. Algunos agentes patógenos pueden impactar la reproducción del wapità y al ganado, pero es raro que se considere para los rumiantes silvestres cuando existe un declive en la productividad de la población. Se investigó la exposición a enfermedades de los wapità utilizando un perfil de aborto bovino (e.g. Brucelosis, leptospirosis, rinotraqueitis infecciosa bovina, (RIB), diarrea viral bovina, e infección por Neospora sp.), ya que estas enfermedades pueden afectar negativamente a la reproducción de los bovinos y rumiantes silvestres, y el wapità y el ganado frecuentemente co-ocurren. Utilizamos una regresión logÃstica jerárquica para modelar la proporción de preñez de las hembras en periodo de lactancia (un sustituto para la supervivencia de la crÃa al destete) como una función de la población y la exposición de las enfermedades reproductivas. Se hicieron pruebas a poblaciones de wapità y fueron expuestos a 2-4 de los agentes patógenos evaluados, excepto para la brucelosis, que no estaba presente. La preñez de las hembras osciló entre 0.73-0.96 y la proporción de supervivencia al pre-destete desde 0.40-0.67 entre poblaciones. La época de preñez varió por población en todos los contrastes (P <0,016), pero no por la exposición a cualquier enfermedad (P> 0,213). La proporción de hembras lactantes en otoño no varió entre las poblaciones (P> 0,247), ni por la exposición a cualquier patógeno (P> 0,281). La exposición a patógenos no afectó la productividad del wapitÃ, a pesar de los niveles de exposición que reflejan previos estudios en Estados Unidos de Norteamérica y la baja preñez y la sobrevivencia de crÃas entre algunas poblaciones. Debido a su presencia en todas las poblaciones de wapità en Estados Unidos de Norteamérica, si los productores de ganado adyacentes a los sitios de introducción de wapità en México están viendo menos crÃas que las esperadas, es posible que quieran vigilar su ganado para IBR para ver si BHV-1 puede ser un posible factor contribuyente, ya que el patógeno está relacionado con la reproducción y es probable que esté presente en los wapitÃ
Cervus elaphus
We evaluated Cervus elaphus herbivory and trampling impacts on plants and soils on Chaco Culture National Historical Park (Chaco), a desert grass/shrubland in northwestern New Mexico, USA, most (63%) of which has been protected from grazing by domestic livestock since 1948. We conducted grazing, browse, and water infiltration surveys in areas which received different amounts of C. elaphus use (use and control), 2004–2007. Browse utilization was <32% on monitored species and Odocoileus hemionus use accounted for the majority of browsing. Live plant cover was greater on areas receiving more C. elaphus use, and no grass species were used above recommended levels. Stubble heights of Bouteloua spp. were positively related to relative C. elaphus use on some areas, suggesting possible stimulation of grassland productivity by C. elaphus grazing. Water infiltration rates either did not differ among use or control sites or were faster in use sites, indicating no impacts of C. elaphus use on soil compaction. At current C. elaphus densities (0.2–0.4/km2), negative impacts to plants and soils were not seen on Chaco, and some evidence suggests that light grazing is optimizing desert grasslands of Chaco
Factors influencing survival and productivity of pronghorn in a semiarid grass-woodland in east-central New Mexico
Pronghorns (Antilocapra americana) are an important source of revenue and recreation for property managers throughout New Mexico, but have been declining in number. We documented body condition, survival, production of fawns, and trends in population size of pronghorns on the Corona Range and Livestock Research Center (CRLRC), a working research ranch and wildlife enterprise located in east-central New Mexico, from 2006 through 2011. Accrual of all indices of condition and size of both adult female and adult male pronghorns was positively associated with precipitation during June to July, August to September, and annually. Annual survival rates of females (0.33 to 0.78) and males (0.63 to 0.89) were highly variable on CRLRC. Survival of individuals was not related to any measure of condition or size taken the prior autumn. Survival of adult females was related to reproductive status the previous year; females that had successfully weaned \u3e1 fawn the previous year were 0.11 times less likely to survive. Malnutrition was the most common cause of mortality (nine of 22 females; seven of 15 males), followed by suspected plant toxicities and enterotoxaemia (nine of 22 females) and harvest (six of 15 males). Most adult female mortality (73%) occurred after parturition and prior to weaning when energy demands are greatest on adult females; females that successfully weaned \u3e1 fawn accrued significantly less condition by autumn. Survival of fawns was related to maternal condition, and fawn:adult female ratios were positively correlated with cumulative precipitation during late gestation and parturition. Low survival of adult females and fawns has resulted in the CRLRC pronghorn population declining from a minimum of 136 individuals to 66 from 2005 to 2011. Timing and causes of mortality highlight a strong nutritional limitation faced by lactating females related to the most energetic costs of reproduction being borne prior to the onset of summer monsoonal precipitation. The poor timing of reproduction to precipitation (and, thus, to forage phenology) in the southwestern United States will likely always limit productivity and survival of pronghorn relative to northern populations
Impacts of chronic wasting disease on a low density mule deer (Odocoileus hemionus) population in the San Andres Mountains, Chihuahuan Desert, New Mexico
Chronic wasting disease (CWD), a contagious neurodegenerative disease of cervids, is becoming increasingly prevalent in the arid Southwest including the Chihuahuan Desert ecoregion. Population effects of CWD are uncertain, particularly in arid environments, as previous work has been on relatively high density deer populations in semi-arid or temperate environments. In 2002, CWD was detected in a low density mule deer (Odocoileus hemionus) population in the arid San Andres Mountains, a Chihuahuan Desert range in southern New Mexico. We determined prevalence and distribution of CWD, and mortality and movements of deer, to assess the potential impact on low density deer populations in arid environments. Repeated seasonal primarily ante-mortem sampling found stable prevalence of 0.000–0.091, 2003–2008. Annual CWD mortality rate was <0.02, including deer that were culled. Monitoring of adult radio-collared deer showed no dispersal movements away from home ranges, with maximum movements of ≤20 km; similarly, no juveniles dispersed from maternal ranges. Distribution of infected deer was strongly related to presence of other infected deer. Annual survival rates of mule deer and population rate-of-increase suggested little effect of CWD on population-level mortality given observed prevalence. Transmission and reservoirs of CWD in the SAM were likely limited by low deer densities, patchy distribution, and environmental characteristics (i.e., low clay content of soils) unfavorable to prion persistence, characteristics that are typical of most mule deer populations in the Chihuahuan Desert ecoregion.La enfermedad crónica degenerativa (por sus siglas en inglés: CWD), una enfermedad neurodegenerativa contagiosa de los cérvidos, se está haciendo cada vez más frecuente en el suroeste árido americano incluyendo la ecoregión del desierto de Chihuahua. Los efectos de la CWD sobre poblaciones de cérvidos silvestres son inciertos, particularmente en ambientes áridos, ya que el trabajo previo ha estado en poblaciones de ciervos de densidad relativamente alta en ambientes semi-áridos o templados. En 2002, la CWD fue detectada en una población de venado bura (Odocoileus hemionus) de baja densidad en las áridas montañas de San Andrés, una región del Desierto Chihuahuense en el sur de Nuevo México. Se determinó la prevalencia y distribución de CWD, y la mortalidad y los movimientos de los venados, para evaluar su impacto potencial en poblaciones de baja densidad en ambientes áridos. En el muestreo ante-mortem previo repetido estacionalmente se encontró prevalencia estable de 0,000–0,091, 2003–2008. La tasa anual de mortalidad por CWD fue <0,02, incluyendo venados que fueron sacrificados. El monitoreo de venados con radio-collares adultos no mostró movimientos de dispersión fuera de los rangos de origen, con movimientos máximos de ≤20 km; de manera similar, no hay juveniles dispersos de los rangos maternos. La distribución de los venados infectados estaba fuertemente relacionada con la presencia de otros venados infectados. Las tasas anuales de supervivencia del venado mula y la tasa de aumento de la población sugirieron un efecto pequeño de la CWD en la mortalidad a nivel de la población dada la prevalencia observada. La transmisión y los depósitos de CWD en el SAM (Montañas San Andrés) fueron probablemente limitados por la baja densidad de los venados, su distribución irregular y las caracterÃsticas ambientales (es decir, bajo contenido de arcilla de los suelos) desfavorables a la persistencia de priones, caracterÃsticas tÃpicas de la mayorÃa de las poblaciones de venados bura en la ecorregión del Desierto Chihuahuense
Asymptotically Matched Spacetime Metric for Non-Precessing, Spinning Black Hole Binaries
We construct a closed-form, fully analytical 4-metric that approximately
represents the spacetime evolution of non-precessing, spinning black hole
binaries from infinite separations up to a few orbits prior to merger. We
employ the technique of asymptotic matching to join a perturbed Kerr metric in
the neighborhood of each spinning black hole to a near-zone, post-Newtonian
metric farther out. The latter is already naturally matched to a far-zone,
post-Minkowskian metric that accounts for full temporal retardation. The result
is a 4-metric that is approximately valid everywhere in space and in a small
bundle of spatial hypersurfaces. We here restrict our attention to quasi-
circular orbits, but the method is valid for any orbital motion or physical
scenario, provided an overlapping region of validity or buffer zone exists. A
simple extension of such a metric will allow for future studies of the
accretion disk and jet dynamics around spinning back hole binaries
Conectividad entre las poblaciones de jaguar en la Sierra Madre Oriental, México
"Introduction: The jaguar (Panthera onca) is an apex carnivore that is vulnerable to habitat fragmentation, and some of its populations are believed to be isolated in México where it is classed as endangered. The main the objective of our study was to evaluate connectivity of available jaguar habitat from the Sierra Madre Oriental of México (SMO) towards southern México.
Methods: We determined least-cost pathways for jaguar movements among habitat patches in the SMO and identified potential corridors from the SMO. We used recent jaguar presence data and maximum entropy modeling to identify habitat patches in the SMO. We then used the Analytical Hierarchy Process to generate input values for a resistance (landscape permeability) matrix for jaguar movements that we generated using Multi-Criteria-Evaluation with a weighted linear combination. We then modeled least-cost pathways for both dispersal and local movements of jaguars.
Results: We identified 581 potential highly suitable habitat patches for the jaguar. Of these, three were > 100 km2 and thus met the criteria for fundamental (i. e. capable of supporting a viable jaguar population) patches. The resistance matrix contained 3 % of low cost and 49 % intermediate cost areas for jaguar movements. Least-cost pathways analysis showed 61 dispersal routes totaling > 2,000 km and > 200 travel routes, with the largest number of both route types in Hidalgo. We also identified potentially five significant corridors for jaguar movement within the SMO and south towards southern México populations.
Discussion and implications: We determined that the SMO contains significant jaguar habitat with multiple biological corridors for connectivity with more southern populations of jaguar in México. Based on this, we recommend development of management strategies to facilitate exchange of individuals from the SMO with other known jaguar populations in southern states (i. e. Oaxaca, Tabasco, Guerrero). Principal strategies may focus on habitat management of fundamental patches and habitat restoration between or around stepping-stones. Promoting connectivity among patches and populations which inhabit the SMO will increase its potential as a biodiversity conservation area.
Adaptability of the threatened jaguarundi (Herpailurus yagouaroundi Schereber, 1777) to human-altered environments in San Luis PotosÃ, Mexico
La persistencia y recuperación de especies raras en regiones en desarrollo con áreas protegidas limitadas depende de su adaptabilidad a los hábitats alterados por el hombre. El jaguarundi (Herpailurus yagouaroundi) está clasificado como amenazado en México, y el conocimiento de su distribución y su correlación con el ambiente es necesario para los esfuerzos de recuperación informados. Sin embargo, poco se sabe sobre el hábitat o la distribución de jaguarundi en el interior de México, incluido el estado de San Luis Potosà (SLP). Realizamos 96 entrevistas semiestructuradas en comunidades, ejidos y ranchos a lo largo de SLP para obtener registros de la presencia de jaguarundi e identificar correlaciones ambientales y atributos de sitios asociados con su ocurrencia. Evaluamos las entrevistas utilizando criterios analÃticos de credibilidad y recopilamos información sobre hábitats de 50 eventos confiables de tres de las cuatro regiones geográficas de SLP. En comparación con el paisaje de SLP, las ocurrencias de jaguarundi se ubicaron más cerca del agua, más cerca de las carreteras, a bajas elevaciones, marginalmente más cerca de las comunidades, y en áreas con mayor borde total, densidad de bordes y número de parches de paisaje. El jaguarundi mostró preferencia por los mosaicos de bosques tropicales, agrÃcolas, de pastizales y urbanos (es decir, cualquier comunidad). Coberturas de escondite relativamente denso o de emboscada generalmente estaban presentes en los sitios de ocurrencia. Colectivamente, el modelo de máxima entropÃa y el modelo de regresión logÃstica predijeron una probabilidad similar y alta de presencia de jaguarundi en regiones caracterizadas por mosaicos de bosques tropicales, agricultura, pastizales o tipos de cobertura urbana <500 m en elevación y <2 km desde carreteras. Estos paisajes de mosaicos tendÃan a estar relativamente cerca de comunidades de densidades moderadas de población y agua, y generalmente soportan densidades de presas pequeñas más altas que las áreas menos fragmentadas. Los jaguarundi se adaptaron al menos a las perturbaciones ligeras y moderadas relacionadas con los seres humanos, y pueden verse beneficiados por el aumento de los mosaicos de borde y hábitat.Persistence and recovery of rare species in developing regions with limited protected areas depends upon their adaptability to human-altered habitats. The jaguarundi (Herpailurus yagouaroundi) is classed as threatened in Mexico, and knowledge of its distribution and environmental correlates is necessary for informed recovery efforts. However, little is known of jaguarundi habitat or distribution in interior Mexico, including the state of San Luis Potosà (SLP). We conducted 96 semi-structured interviews around communities, ejidos, and ranches throughout SLP to obtain records of jaguarundi presence and identify environmental correlates and site attributes associated with its occurrence. We evaluated interviews using analytical criteria of credibility, and collected habitat information from 50 reliable occurrences from three of the four geographic regions of SLP. Compared to the SLP landscape, jaguarundi occurrences were located closer to water, closer to roads, at lower elevation, marginally closer to communities, and in areas with greater total edge, edge density, and number of landscape patches. Jaguarundi showed preference for mosaics of tropical forest, agricultural, grassland, and urban (i.e., any community) cover types. Relatively dense hiding or ambush cover was usually present at occurrence sites. Collectively, maximum entropy modeling and logistic regression modeling predicted similar and high likelihood of jaguarundi presence in regions characterized by mosaics of tropical forest, agriculture, grassland, or urban cover types <500 m in elevation and <2 km from roads. These mosaic landscapes tended to be relatively close to communities of moderate population densities and water, and typically support higher small prey densities than less fragmented areas. Jaguarundi were adaptable to at least light–moderate human-related disturbance, and may be benefitted by it because of increased edge and habitat mosaics
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