28 research outputs found

    PRIMER REGISTRO DEL TIGRILLO (LEOPARDUS WIEDII, SCHINZ 1821) Y DEL GATO MONTÉS (LYNX RUFUS, KERR 1792) EN LA RESERVA DE LA BIÓSFERA DE TEHUACÁN-CUICATLÁN, OAXACA, MÉXICO

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    Using camera-traps, two new records of margay (Leopardus wiedii) and two of lynx (Lynx rufus) were obtained at the Biosphere Reserve de Tehuacán-Cuicatlán, Oaxaca, Mexico, in 2003 and 2004. These are the first records documenting the presence of both species in this reserve

    Análisis panbiogeográfico de Vexillata (Nematoda: Ornithostrongylidae) y sus huéspedes (Mammalia: Rodentia)

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    A panbiogeographic analysis was carried out, based on a parsimony analysis of endemicity (PAE) to analyze the species of helminth intestinal parasites of the genus Vexillata (Nematoda: Ornithostrongylidae) and their host species, mammals of the families Geomyidae and Heteromyidae. Two analyses were undertaken, the first using only those species of Vexillata with more than two localities, and the second analyzing all localities of this genus as a single track. Three generalized tracks were obtained by the first PAE: northern coast of Venezuela, Central America and Nearctic. Only one track was identified by a parasite and its host (V. tejerai and Heteromys anomalus). It proposes the existence of two biogeographical nodes, the first is located between the northern coast of Venezuela and Central America, on the boundaries of northeast Colombia and Panama (Colombia node); and the other in Central Mexico. Those track and nodes overlap with some proposed by other authors. In general, it appears that these systems can be explained as three biotic components. In the case of the South American component might correspond with the isolation of species (V. scorzai), as well as by species that had expanded their geographical distribution (V. tejerai), it could be related to mobilism stages of their host (Heteromys).Se llevó a cabo un análisis panbiogeográfico, a partir de un análisis de parsimonia de endemismos (PAE) de las especies de helmintos parásitos intestinales del género Vexillata (Nematoda: Ornithostrongylidae) y sus especies de huéspedes, mamíferos de las familias Geomyidae y Heteromyidae. Se realizaron dos análisis, el primero empleando solo aquellas especies del género Vexillata con más de dos localidades, y el segundo, analizando todas las localidades de este género de parásito en unsolo trazo individual. Se obtuvieron tres trazos generalizados a partir del PAE del primer análisis: costa norte de Venezuela, América Central y Neártico. Solo uno de los trazos fue sustentado por una especie de parásito y su huésped (V. tejerai y Heteromys anomalus). Se propone la existencia de un nodo biogeográficoen Colombia, entre el trazo de la costa norte de Venezuela y el de América Central en el noroeste de Colombia, en los límites con Panamá; y otro en la zona central de México. Estos trazos y nodos coinciden con algunos propuestos por otros autores. En general se observa que estos sistemas pueden ser explicados como tres componentes bióticos. En particular el de América del Sur puede corresponder con aquellas que especiaron por aislamiento (V. scorzai), y especies con distribuciones amplias (V. tejerai), quizá más relacionadas a etapas de movilidad de sus huéspedes (Heteromys)

    WiFi-based urban localisation using CNNs

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    IEEE Conference on Intelligent Transportation Systems - ITSC 2019, 27-30/10/2019, Auckland, Nueva Zelanda.The continuous expanding scale of WiFi deployments in metropolitan areas has made possible to find WiFi access points at almost any place in our cities. Although WiFi has been mainly used for indoor localisation, there is a growing number of research in outdoor WiFi-based localisation. This paper presents a WiFi-based localisation system that takes advantage of the huge deployment of WiFi networks in urban areas. The idea is to complement localisation in zones where the GPS coverage is low, such as urban canyons. The proposed method explores the CNNs ability to handle large amounts of data and their high accuracy with reasonable computational costs. The final objective is to develop a system able to handle the large number of access points present in urban areas while preserving high accuracy and real time requirements. The system was tested in a urban environment, improving the accuracy with respect to the state-of-the-art and being able to work in real time

    Opuntia in México: Identifying Priority Areas for Conserving Biodiversity in a Multi-Use Landscape

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    BACKGROUND: México is one of the world's centers of species diversity (richness) for Opuntia cacti. Yet, in spite of their economic and ecological importance, Opuntia species remain poorly studied and protected in México. Many of the species are sparsely but widely distributed across the landscape and are subject to a variety of human uses, so devising implementable conservation plans for them presents formidable difficulties. Multi-criteria analysis can be used to design a spatially coherent conservation area network while permitting sustainable human usage. METHODS AND FINDINGS: Species distribution models were created for 60 Opuntia species using MaxEnt. Targets of representation within conservation area networks were assigned at 100% for the geographically rarest species and 10% for the most common ones. Three different conservation plans were developed to represent the species within these networks using total area, shape, and connectivity as relevant criteria. Multi-criteria analysis and a metaheuristic adaptive tabu search algorithm were used to search for optimal solutions. The plans were built on the existing protected areas of México and prioritized additional areas for management for the persistence of Opuntia species. All plans required around one-third of México's total area to be prioritized for attention for Opuntia conservation, underscoring the implausibility of Opuntia conservation through traditional land reservation. Tabu search turned out to be both computationally tractable and easily implementable for search problems of this kind. CONCLUSIONS: Opuntia conservation in México require the management of large areas of land for multiple uses. The multi-criteria analyses identified priority areas and organized them in large contiguous blocks that can be effectively managed. A high level of connectivity was established among the prioritized areas resulting in the enhancement of possible modes of plant dispersal as well as only a small number of blocks that would be recommended for conservation management

    Evaluación de la efectividad de las áreas protegidas para contener procesos de cambio en el uso del suelo y la vegetación. ¿Un índice es suficiente? Evaluation of protected area effectiveness for preventing land use and land cover changes in Mexico. Is an index good enough?

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    Se examina la efectividad de 44 áreas protegidas federales (AP) en México para evitar procesos de cambio en el uso del suelo y la vegetación (CUSV) y se comparan los métodos y resultados con los de algunos estudios previos. Se cuantificó el porcentaje de superficie transformada (ST) en 2002 y su tasa de cambio entre 1993 y de 2002 y se compararon las tasas de cambio observadas en las AP, en las áreas circundantes de cada AP y en sus respectivas ecorregiones. Se integró un índice de efectividad y se caracterizaron los procesos de CUSV en cada AP. En 2002, el 77% de las AP analizadas tenía menos de 20% de ST; casi 30% mostró una reducción en la ST, en tanto que en otro 30%, el incremento en la ST fue mayor que la tasa promedio de las AP analizadas. Poco más del 70% de las AP mostraron tasas de CUSV menores a las de sus áreas circundantes y en 80% de las AP, las tasas fueron menores que en sus ecorregiones. En general, estos resultados coinciden con estudios previos, pero existen variaciones según el enfoque metodológico utilizado. Consecuentemente, los índices de efectividad deben complementarse con una caracterización detallada de los procesos de CUSV y la interpretación de los resultados debe matizarse en función de los métodos.<br>Effectiveness of 44 federal protected areas (PA) for preventing land use and land cover changes (LULC) in Mexico is examined, comparing results and methodological approaches used in previous studies. We quantified the percentage of transformed area (TS) in 2002 and its rate of change between 1993 and 2002. We compared observed TS rate of change in PA, adjacent areas, and their ecoregions of location. An effectiveness index was build to produce a characterization of LULC processes developed for each PA. In 2002, 77% PA showed less than 20% covered by TS; nearly 30% of PA showed a reduction of TS. Additionally, in 30% of PA, TS increase exceeded the mean rate for all PA. More than 70% of PA showed lower LULC rates than their surrounding areas, and in 80% of PA, these rates were lower than those observed in their corresponding ecoregions. Overall, PA were effective to prevent LULC processes as previously suggested. However, trends derived from this type of analyses depend on methodological specifications. Effectiveness indexes should be complemented with a detailed characterization of LULC processes and their interpretation should correspond to the specific methodological approach used

    Ecological niche models and patterns of richness and endemism of the southern Andean genus Eurymetopum (Coleoptera, Cleridae)

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    Ecological niche models and patterns of richness and endemism of the southern Andean genus Eurymetopum (Coleoptera, Cleridae). Eurymetopum is an Andean clerid genus with 22 species. We modeled the ecological niches of 19 species with Maxent and used them as potential distributional maps to identify patterns of richness and endemicity. All modeled species maps were overlapped in a single map in order to determine richness. We performed an optimality analysis with NDM/VNDM in a grid of 1((sic)) latitudelongitude in order to identify endemism. We found a highly rich area, located between 32((sic)) and 41((sic)) south latitude, where the richest pixels have 16 species. One area of endemism was identified, located in the Maule and Valdivian Forest biogeographic provinces, which extends also to the Santiago province of the Central Chilean subregion, and contains four endemic species (E. parallelum, E. prasinum, E. proteus, and E. viride), as well as 16 nonendemic species. The sympatry of these phylogenetically unrelated species might indicate ancient vicariance processes, followed by episodes of dispersal. Based oil our results, we suggest a close relationship between these provinces, with the Maule representing a complex area

    Identification of areas of endemism from species distribution models: threshold selection and Nearctic mammals

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    We evaluated the relevance of threshold selection in species distribution models on the delimitation of areas of endemism, using as case study the North American mammals. We modeled 40 species of endemic mammals of the Nearctic region with Maxent, and transformed these models to binary maps using four different thresholds: minimum training presence, tenth percentile training presence, equal training sensitivity and specificity, and 0.5 logistic probability. We analyzed the binary maps with the optimality method in order to identify areas of endemism and compare our results regarding previous analyses. The majority of the species tend to have very low values for the minimum training presence, whereas most of the species have a value of the tenth percentile training presence around 0.5, and the equal training sensitivity and specificity was around 0.3. Only with the tenth percentile threshold we recovered three out of the four patterns of endemism identified in North America, and detected more endemic species.The best identification of areas of endemism was obtained using the tenth percentile training presence threshold, which seems to recover better the distributional area of the mammals analyzed.Evaluamos la relevancia de la selección del umbral en los modelos de distribución de especies en la delimitación de las áreas de endemismo, usando como un caso de estudio a los mamíferos de América del Norte. Modelamos 40 especies de mamíferos endémicos de la región Neártica con Maxent, y transformamos esos modelos a mapas binarios usando cuatro umbrales diferentes: presencia mínima de entrenamiento, percentil diez de la presencia de entrenamiento, igual sensibilidad y especificidad de entrenamiento, y probabilidad logística de 0.5. Los mapas binarios los analizamos con el método de optimación con el objeto de identificar áreas de endemismo y comparar nuestros resultados con estudios previos. La mayoría de las especies mostró tendencias hacia valores muy bajos de la presencia mínima de entrenamiento, mientras que la mayoría tuvo un valor del percentil diez de la presencia de entrenamiento alrededor de 0.5, y de igual sensibilidad y especificidad de entrenamiento alrededor de 0.3. Únicamente con el percentil diez de la presencia de entrenamiento se recuperaron tres de los cuatro patrones de endemismo identificados para América del Norte y se detectaron más especies endémicas. La identificación de áreas de endemismo más eficiente se obtuvo usando el umbral del percentil diez de la presencia de entrenamiento, el cual parece recuperar mejor las áreas de distribución de los mamíferos analizados

    Identification of areas of endemism from species distribution models: Threshold selection and Nearctic mammals

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    Evaluamos la relevancia de la selección del umbral en los modelos de distribución de especies en la delimitación de las áreas de endemismo, usando como un caso de estudio a los mamíferos de América del Norte. Modelamos 40 especies de mamíferos endémicos de la región Neártica con Maxent, y transformamos esos modelos a mapas binarios usando cuatro umbrales diferentes: presencia mínima de entrenamiento, percentil diez de la presencia de entrenamiento, igual sensibilidad y especificidad de entrenamiento, y probabilidad logística de 0.5. Los mapas binarios los analizamos con el método de optimación con el objeto de identificar áreas de endemismo y comparar nuestros resultados con estudios previos. La mayoría de las especies mostró tendencias hacia valores muy bajos de la presencia mínima de entrenamiento, mientras que la mayoría tuvo un valor del percentil diez de la presencia de entrenamiento alrededor de 0.5, y de igual sensibilidad y especificidad de entrenamiento alrededor de 0.3. Únicamente con el percentil diez de la presencia de entrenamiento se recuperaron tres de los cuatro patrones de endemismo identificados para América del Norte y se detectaron más especies endémicas. La identificación de áreas de endemismo más eficiente se obtuvo usando el umbral del percentil diez de la presencia de entrenamiento, el cual parece recuperar mejor las áreas de distribución de los mamíferos analizados
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