Showing papers by "Víctor Sánchez-Cordero published in 2005"

Fine-Scale Predictions of Distributions of Chagas Disease Vectors in the State of Guanajuato, Mexico

Abstract: One of the most daunting challenges for Chagas disease surveillance and control in Mexico is the lack of community level data on vector distributions. Although many states now have assembled representative domestic triatomine collections, only two triatomine specimens had been collected and reported previously from the state of Guanajuato. Field personnel from the state’s Secretaria de Salud conducted health promotion activities in 43 of the 46 counties in the state and received donations of a total of 2,522 triatomine specimens between 1998 and 2002. All specimens were identified, and live insects examined for Trypanosoma cruzi. In an effort to develop fine-scale distributional data for Guanajuato, collection localities were georeferenced and ecological niches were modeled for each species by using evolutionary-computing approaches. Five species were collected: Triatoma mexicana (Herrich-Schaeffer), Triatoma longipennis (Usinger), Triatoma pallidipennis (Stal), Triatoma barberi (Usinger), and Tr...

Pollination ecology of Stenocereus queretaroensis (Cactaceae), a chiropterophilous columnar cactus, in a tropical dry forest of Mexico.

Abstract: Flowers of columnar cacti are animal-pollinated, often displaying a chiropterophylic syndrome. This study examined if the columnar cactus Stenocereus queretaroensis, a tropical species endemic to western Mexico, is bat-pollinated, by studying its pollination biology and the foraging behavior of potential pollinators. Flowers were produced in winter through spring, peaking in April. Anthesis was nocturnal, and stigma and anther turgidity began around 2200 hours. Production of nectar secretion and highest sugar concentration and energy supply were nocturnal, peaking between 2200 and 2400 hours. Manual auto-pollination and exclusion experiments showed that self-pollination yielded no fruits, while nocturnal pollinators resulted in high fruit set and seed set compared to diurnal pollination treatments. The nectar-feeding bat Leptonycteris curasoae (Phyllostomidae) was the main nocturnal pollinator with the highest effective pollination. Peak bat visitation coincided with peaks in nectar production. The high abundance of L. curasoae throughout the 4-yr study, suggests that it is a seasonally reliable pollinator for this columnar cactus. While pollination syndromes have been increasingly called into question in recent years, this study suggests that at least for this system, there is a fairly close fit between pollinator and pollination syndrome.

Place prioritization for biodiversity representation using species' ecological niche modeling

Abstract: Place prioritization for biodiversity representation is essential for conservation planning, particularly in megadiverse countries where high deforestation threatens biodiversity. Given the collecting biases and uneven sampling of biological inventories, there is a need to develop robust models of species' distributions. By modeling species' ecological niches using point occurrence data and digitized environmental feature maps, we can predict potential and extant distributions of species in untransformed landscapes, as well as in those transformed by vegetation change (including deforestation). Such distributional predictions provide a framework for use of species as biodiversity surrogates in place prioritization procedures such as those based on rarity and complementarity. Beyond biodiversity conservation, these predictions can also be used for place prioritization for ecological restoration under current conditions and under future scenarios of habitat change (e.g., deforestation) scenarios. To illustrate these points, we (1) predict distributions under current and future deforestation scenarios for the Mexican endemic mammal Dipodomys phillipsii, and show how areas for restoration may be selected; and (2) propose conservation areas by combining nonvolant mammal distributional predictions as biodiversity surrogates with place prioritization procedures, to connect decreed natural protected areas in a region holding exceptional biodiversity: the Transvolcanic Belt in central Mexico.

Place prioritization for biodiversity content using species ecological niche modeling

Abstract: Place prioritization for biodiversity representation is essential for conservation planning, particularly in megadiverse countries where high deforestation threatens biodiversity. Given the collecting biases and uneven sampling of biological inventories, there is a need to develop robust models of species’ distributions. By modeling species’ ecological niches using point occurrence data and digitized environmental feature maps, we can predict potential and extant distributions of species in untransformed landscapes, as well as in those transformed by vegetation change (including deforestation). Such distributional predictions provide a framework for use of species as biodiversity surrogates in place prioritization procedures such as those based on rarity and complementarity. Beyond biodiversity conservation, these predictions can also be used for place prioritization for ecological restoration under current conditions and under future scenarios of habitat change (e.g., deforestation) scenarios. To illustrate these points, we (1) predict distributions under current and future deforestation scenarios for the Mexican endemic mammal Dipodomys phillipsii, and show how areas for restoration may be selected; and (2) propose conservation areas by combining nonvolant mammal distributional predictions as biodiversity surrogates with place prioritization procedures, to connect decreed natural protected areas in a region holding exceptional biodiversity: the Transvolcanic Belt in central Mexico. La seleccion de areas prioritarias de conservacion es fundamental en la planeacion sistematica de la conservacion, particularmente en paises de mega-diversidad, en donde la alta deforestacion es una de las amenazas a la biodiversidad. Debido a los sesgos taxonomicos y geograficos de colecta de los inventarios biologicos, es indispensable generar modelos robustos de distribucion de especies. Al modelar el nicho ecologico de especies usando localidades de colecta, mapas digitales de variables ambientales y sistemas de informacion geograficos, se proyecta las distribuciones potencial y actual en habitat transformados y no transformados por la deforestacion. Estas hipotesis de distribucion proveen un marco teorico para predecir presencia y ausencia de especies, como indicadores de la biodiversidad existente en areas prioritarias seleccionadas con base en los principios de rareza y complementariedad. Para ilustrar esto, se muestran dos ejemplos; (1) se modelo el nicho ecologico de un roedor endemico Dipodomys phillipsii, proyectando su distribucion en escenarios de deforestacion actuales y a futuro. La prediccion de la distribucion de especies puede ser util en la seleccion de areas prioritarias para la conservacion y la restauracion, bajo escenarios actuales y futuros de deforestacion, permitiendo una planeacion sistematica adecuada de la conservacion de la biodiversidad, y (2) proponer areas de conservacion, usando predicciones de distribuciones de mamiferos no voladores y procedimientos de seleccion de areas prioritarias, como corredores que conecten las areas naturales prioritarias decretadas en el Eje Neovolcanico, una region de alta biodiversidad.

Distribución de roedores reservorios del virus causante del síndrome pulmonar por hantavirus y regiones de posible riesgo en méxico

Abstract: We determined distributions of rodent species known as reservoirs of Sin Nombre virus, causal agent for the hantavirus pulmonary syndrome (HPS). In the absence of HPS cases reported in Mexico, this study aimed to identify potential risk regions for HPS based on distributions of these rodent reservoirs. We modeled species’ ecological niches and projected them as potential distributions using point occurrence data, environmental digital maps, the genetic algorithm GARP (Genetic Algorithm for Rule-set Prediction), and GIS. We determined potential distributions of three rodents known to serve as reservoirs for Sin Nombre virus, four additional rodent species that may also play a role, as well as all Peromsycus species, considered as potential reservoirs for Sin Nombre virus or other hantaviruses in Mexico. Geographic locations of HPS cases coincided significantly with modeled potential

Nuevos registros del «tepezcuintle» (Agouti paca) para el norte del estado de Oaxaca, México

Abstract: USING CAMERA-TRAPS IN JULY 2004, TWO NEW RECORDS OF THE TEPEZCUINTLE (AGOUTI PACA) WERE OBTAINED IN THE NORTH OF THE STATE OF OAXACA, MEXICO. THIS RECORDS WIDEN THE DISTRIBUTIONAL RANGE APPROXIMATELY 60 KM WEST OF THE PREVIOUS DISTRIBUTION PROPOSED FOR THIS SPECIES.