Time filter

Source Type

Large groups of whale sharks (Rhincodon typus) are common in the North Mexican Caribbean and gather between May and September each year. We describe their spatial and temporal distribution, and the physicochemical (temperature, dissolved oxygen, light extinction coefficient and salinity) and biological conditions during the presence and absence seasons of R. typus. A total of 26 sampling stations were monitored to record whale shark sightings and physicochemical variables during 10 field campaigns from April 2005 to March 2006. At each station, zooplankton and water samples, for chlorophyll-a and nutrients determination, were collected. Physicochemical conditions were significantly different between presence-absence seasons (ANOSIM, Rglobal = 0.632). The R. typus season was characterized by low salinity values, and higher temperature, chlorophyll-a, dissolved oxygen and inorganic nitrogen concentrations values. Average zooplankton biomass was lower during the absence season, while recorded the maximum values during the presence one. Furthermore, these values were also observed in areas with higher species abundances, supporting the hypothesis that the site is used by R. typus primarily as a foraging area. We conclude that physicochemical conditions of the study area promote the biological productiv-ity, which explains the spatial and temporal variability of R. typus. Source

Rodriguez-Soto C.,National Autonomous University of Mexico | Monroy-Vilchis O.,National Autonomous University of Mexico | Maiorano L.,University of Rome La Sapienza | Maiorano L.,University of Lausanne | And 6 more authors.
Diversity and Distributions

Aim The jaguar, Panthera onca, is a species of global conservation concern. In Mexico, the northernmost part of its distribution range, its conservation status, is particularly critical, while its potential and actual distribution is poorly known. We propose an ensemble model (EM) of the potential distribution for the jaguar in Mexico and identify the priority areas for conservation. Location Mexico. Methods We generated our EM based on three presence-only methods (Ecological Niche Factor Analysis, Mahalanobis distance, Maxent) and considering environmental, biological and anthropogenic factors. We used this model to evaluate the efficacy of the existing Mexican protected areas (PAs), to evaluate the adequacy of the jaguar conservation units (JCUs) and to propose new areas that should be considered for conservation and management of the species in Mexico. Results Our results outline that 16% of Mexico (c.312,000km2) can be considered as suitable for the presence of the jaguar. Furthermore, 13% of the suitable areas are included in existing PAs and 14% are included in JCUs (Sanderson, 2002). Main conclusions Clearly much more should be carried out to establish a proactive conservation strategy. Based on our results, we propose here new jaguar conservation and management areas that are important for a nationwide conservation blueprint. © 2011 Blackwell Publishing Ltd. Source

Mendez D.,Autonomous University of Yucatan | Cuevas E.,Pronatura Peninsula de Yucatan | Navarro J.,Autonomous University of Yucatan | Gonzalez-Garza B.I.,National Polytechnic Institute of Mexico | Guzman-Hernandez V.,Area de Proteccion de Flora y Fauna Laguna de Terminos
Revista de Biologia Marina y Oceanografia

From the 32 worldwide post nesting Chelonia mydas sub populations 2 are found in the Mexican Coasts, one of them in Michoacan (Pacific Ocean) and the other in the Yucatán Peninsula (Atlantic Ocean). Lack of information about migration patterns, home ranges and anthropogenic interaction are factors that contribute to the intrinsic vulnerability of C. mydas populations anywhere around the world. The objective of this investigation was to identify migration routes and critical marine habitats for post nesting C. mydas individuals in the Yucatán Peninsula. Between June 2011 and January 2012 4 C. mydas post nesting individuals were tracked using satellite telemetry, 2 of them from continental beaches and the other 2 from insular ones. A geographic information system was used to integrate the collected information and used to identify migration routes for C. mydas as well as to estimate their home ranges. Three turtles moved and remained over the marine platform in the Banco de Campeche in Mexican territory, while one of the turtles migrated outside Mexican waters to Dry Tortuga (Florida, USA). The home ranges areas used by nesting females in continental beaches were significantly larger and further from the coast compared to those registered for females tracked from insular beaches. Based on the results we recommend management strategies planning for conservation of C. mydas in the Yucatán Peninsula. Source

Lopez-Toledo L.,National Autonomous University of Mexico | Lopez-Toledo L.,Institute for Conservation Research | Horn C.,Institute for Conservation Research | Lopez-Cen A.,Pronatura Peninsula de Yucatan | And 2 more authors.
Economic Botany

Potential Management of Chamaedorea seifrizii (Palmae), a Non-timber Forest Product from the Tropical Forest of Calakmul, Southeast Mexico. Leaves and seeds of Chamaedorea (xate) palms are important non-timber forest products (NTFPs). In the Calakmul region (Yucatan Peninsula) of Mexico, several communities have sporadically collected and sold seeds of C. seifrizii since 1980. However, harvesting has intensified recently, raising concerns about overexploitation. To evaluate the economic potential of leaf and seed exploitation in the area, we collected information on abundance, population patterns, and leaf and seed stocks in Ejido Conhuas, a community within the Calakmul Biosphere Reserve (CBR). Then we combined these data with current market values and hypothetical management regimes obtained from the literature for leaves and seeds. Conducting a quantitative analysis of 43 0.1ha plots with differences in forest and soil type, we assessed the abundance of C. seifrizzi in the area. We also conducted interviews to estimate the importance of xate in the local economy. We found C. seifrizii density to be highly variable, with a mean (±SE) of 295 (±35), with forest type being the most influential factor. Population structures differ between forest types, with healthy populations in medium and lower forest. We found a mean density of leaves of harvestable size of 3,750 (±380) leaves ha-1, while seed production was 1.5 (±0.3) kg/ha-1 of fresh seeds. Assuming sustainable harvest rates of 30-50% for leaves and 80% for seeds, one hectare of forest could generate USD 7.0-15.9/ha-1. Considering the number of households (102) and 10% of the total area managed each year (5,700 ha), this harvest could generate a household income of USD 391-838 annually. At the moment, xate trade represents a minor component in the economy of the community, but given the area's extensive forest (>57,000 ha), the resource abundance, and the low human population, we believe the NTFPs derived from C. seifrizii have a potentially great economic impact in the area. © 2011 The New York Botanical Garden. Source

Discover hidden collaborations