Predicted and verified distributions of Ateles geoffroyi and Alouatta palliata in Oaxaca, Mexico

Abstract

Primate conservation requires a better knowledge of the distributions and statuses of populations in both large areas of habitat and in areas for which we currently have no information. We focused on spider monkeys (Ateles geoffroyi) and howler monkeys (Alouatta palliata) in the state of Oaxaca, Mexico. This Mexican state has protected large tracts of forest, and has historical records for both primates, although very little is known about them. To update our knowledge of the distributions of these primates and identify potential areas in which they are present, we modeled their geographic distributions by characterizing their ecological niches using the genetic algorithm for rule-set production (GARP), performed interviews and carried out field surveys. The predicted distributions, surveys and interviews indicate that the distributions of these primates are restricted to northeastern Oaxaca. The results suggest that spider monkeys occupy a wider area and elevational range than howler monkeys. Throughout that range there is a wide variety of suitable habitats for these primates. Most of the sites where monkeys were recorded in the field are not officially protected and there was evidence of hunting and habitat destruction. It is important to improve protection, economic alternatives and environmental education as we move towards an integral solution for the conservation of these species. Validation of the GARP model was done for A. geoffroyi, since we had obtained enough field data for this species; this validation indicated that the predicted distribution of the species was statistically better than expected by chance. Hence, ecological niche modeling is a useful approach when performing an initial assessment to identify distribution patterns, detecting suitable areas for future exploration, and for conservation planning. Our findings provide an improved basis for primate conservation and productive fieldwork in Oaxaca.

Potential distribution of Mexican primates: modeling the ecological niche with the maximum entropy algorithm

“…The probability of this species' presence is also high for sites in Chiapas and southeastern Veracruz, which concurs with the proposal of Estrada and Coates-Estrada (1984) who stated that these regions offer suitable habitats for Ateles and Alouatta. We also found areas of probable occurrence on the Isthmus of Tehuantepec, the Sierra Madre Mountain Range, and the Chimalapas region in Oaxaca, as well as overlapping the niche of A. palliata, which coincides with information reported by Ortíz-Martínez et al (2008). In addition, our model also suggests a high probability of occurrence for Ateles geoffroyi in the region known as the Oaxaca Coast, where there is low and medium-height deciduous and semievergreen forest.…”

“…Methods used include field surveys (Leopold 1959;Estrada and Coates-Estrada 1984;Horwich and Johnson 1986) to analyses using geographic information systems (Luecke 2004;Baumgarten and Williamson 2007), and preliminary analyses of ecological niche modeling in some specific regions (Ramos-Fernández et al 2007;Ortíz-Martínez et al 2008). However, these approximations are limited to small areas.…”

Delineating Ecological Boundaries of Hanuman Langur Species Complex in Peninsular India Using MaxEnt Modeling Approach

“…Martinez et al, [18] observe that these ecological niche models, by identifying consistent differentiation patterns in characters related to the ecological niche, might provide alternative means of recognizing putatively independent lineages and thus act as an effective tool in delimiting species boundaries. These models which largely employ empirical data are useful to characterize species ecological requirements [19], [20], [21], understand distributions, biogeography and dispersal barriers [10], [22], identify effects of climate change [14], [23], forecast species invasions [24], realize the effects of habitat alterations [25], delimit species boundaries [9], [11], [12], [13] and predict unknown populations and species [26], [27].…”

Geographical Distribution of the Space-Weaving Spider,Chibchea salta, from Northwestern Argentina: New Records and Bioclimatic Modeling

“…As in other cases (Elith et al 2006; Pearson et al 2007; Ortiz-Martínez et al 2008; Boubli and de Lima 2009;), the bioclimatic analysis proved to be a valuable means to get insight of the fundamental niche features of a species with still scarce records and almost no previous ecological knowledge. Both methods performed consistently well considering that a narrow-ranged yungas species — probably a true endemics species — was used.…”