Densidad poblacional del tapir centroamericano (Tapirella bairdii) en bosque mesófilo de montaña en Totontepec Villa de Morelos, Oaxaca, México

Botello, Francisco; Romero-Calderón, Ana G.; Sánchez-Hernández, Jhovani; Hernández, Omar; López-Villegas, Gerónimo; Sánchez‐Cordero, Víctor

doi:10.1016/j.rmb.2017.10.016

Cited by 6 publications

(5 citation statements)

References 21 publications

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“…Finally, Botello et al. (in press) estimate 0.32 individuals/km 2 using capture–recapture methods with camera traps in cloud forest in Oaxaca state Mexico, while our model estimates a mean of 0.63 individuals/km 2 in the same study area. None of these differences are on the order that we see between expert estimates of the population for the entire species, compared to the total population estimate across viable cores using our model estimates.…”

Section: Resultsmentioning

confidence: 57%

Using a novel model approach to assess the distribution and conservation status of the endangered Baird's tapir

Schank

Cove

Kelly

et al. 2017

Diversity and Distributions

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Aim:We test a new species distribution modelling (SDM) framework, while comparing results to more common distribution modelling techniques. This framework allows for the combination of presence-only (PO) and presence-absence (PA) data and accounts for imperfect detection and spatial bias in presence data. The new framework tested here is based on a Poisson point process model, which allows for predictions of population size. We compared these estimates to those provided by experts on the species. Species and Location: Presence data on Baird's tapir (Tapirus bairdii) throughout its range from southern México to northern Colombia were used in this research, primarily from the years 2000 to 2016. Methods: Four SDM frameworks are compared as follows: (1) Maxent, (2) a presenceonly (PO) SDM based on a Poisson point process model (PPM), (3) a presence-absence (PA) SDM also based on a PPM and (4) an Integrated framework which combines the previous two models. Model averaging was used to produce a single set of coefficient estimates and predictive maps for each model framework. A hotspot analysis (Gi*) was used to identify habitat cores from the predicted intensity of the Integrated model framework. Results: Important variables to model the distribution of Baird's tapir included land cover, human pressure and topography. Accounting for spatial bias in the presence data affected which variables were important in the model. Maxent and the Integrated model produced predictive maps with similar patterns and were considered to be more in agreement with expert knowledge compared to the PO and PA models.Main conclusions: Total abundance as predicted by the model was higher than expert opinion on the species, but local density estimates from our model were similar to available independent assessments. We suggest that these results warrant further validation and testing through collection of independent test data, development of more precise predictor layers and improvements to the model framework.

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Section: Resultsmentioning

confidence: 57%

Using a novel model approach to assess the distribution and conservation status of the endangered Baird's tapir

Schank

Cove

Kelly

et al. 2017

Diversity and Distributions

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“…Although the low density of Baird's tapir in the Sierra Madre de Chiapas may be a result of poaching and habitat loss (de la Torre et al, 2018), the large variations in density estimated in previous studies may be related to data quality and methods of data analysis. For example, some studies that used capture–recapture models and resulted in the highest density values (Mejía-Correa et al, 2010; González-Maya et al, 2012; Botello et al, 2017) deployed ≤ 10 camera trap stations, with an effective sampling area of 7–19 km 2 estimated from ½ mean maximum distance moved (Table 5). This approach is now known to overestimate density because spatial information related to home range and movement obtained from camera-trap locations is not adequately integrated into modeling (Noss et al, 2012; Tobler & Powell, 2013).…”

Section: Discussionmentioning

confidence: 99%

“…Populations are declining because of poaching, droughts and habitat loss caused by land-use change, and logging and fires (García et al, 2016). However, the extent of this decline is not well known because there is no reliable information on population density and size across most of the species’ range (Naranjo, 2009; Mejía-Correa et al, 2010; González-Maya et al, 2012; Carbajal-Borges et al, 2014; Lavariega-Nolasco et al, 2016; Botello et al, 2017). With an estimated global total of c. 3,000 adults, Baird's tapir is categorized as Endangered on the IUCN Red List, (García et al, 2016), although variations in estimates (Naranjo, 2009; García et al, 2016; Schank et al, 2017) reflect uncertainty about the size of the population.…”

Section: Introductionmentioning

confidence: 99%

Tapirs in trouble: estimating Baird's tapir densities in the Sierra Madre de Chiapas, Mexico

Rivero

Torre

Camacho³

et al. 2021

Oryx

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Spatial capture–recapture models have been widely used to estimate densities of species where individuals can be uniquely identified, but alternatives have been developed for estimation of densities for unmarked populations. In this study we used camera-trap records from 2018 to estimate densities of a species that does not always have individually identifiable marks, Baird's tapir Tapirus bairdii, in the Sierra Madre de Chiapas, southern Mexico. We compared the performance of the spatial capture–recapture model with spatial mark–resight and random encounter models. The density of Baird's tapir did not differ significantly between the three models. The estimate of density was highest using the random encounter model (26/100 km2, 95% CI 12–41) and lowest using the capture–recapture model (8/100 km2, 95% CI 4–16). The estimate from the spatial mark–resight model was 10/100 km2 (95% CI 8–14), which had the lowest coefficient of variation, indicating a higher precision than with the other models. Using a second set of camera-trap data, collected in 2015–2016, we created occupancy models and extrapolated density to areas with potential occupancy of Baird's tapir, to generate a population estimate for the whole Sierra Madre de Chiapas. Our findings indicate the need to strengthen, and possibly expand, the protected areas of southern Mexico and to develop an action plan to ensure the conservation of Baird's tapir.

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“…The differences in reported estimates of home range size could be due to differences in the methodology used and differences in topography and the availability of resources, specifically regarding the availability of water. In mountainous sites with complex topography and permanent availability of quality water throughout the year, the home range could be much smaller than in flat sites with very marked seasonality (Botello et al 2017). Interestingly, using a site area of 16 km 2 provides a total population estimate that is within the range of expert estimates for the species (Fig.…”

mentioning

confidence: 86%

“…Piñera 1995, Gonzalez-Maya et al 2012, Carbajal-Borges et al 2014, Mejía-Correa et al 2014, Botello et al 2017). The estimates from those studies were similar to the estimates using the ISDM, which provided a conflicting story, as the total population estimates were thought to be overestimates by at least an order of magnitude.…”

Section: Environmental Conservationmentioning

confidence: 99%

A Sensitivity Analysis of the Application of Integrated Species Distribution Models to Mobile Species: A Case Study with the Endangered Baird’s Tapir

et al. 2019

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SummarySpecies distribution models (SDMs) are statistical tools used to develop continuous predictions of species occurrence. ‘Integrated SDMs’ (ISDMs) are an elaboration of this approach with potential advantages that allow for the dual use of opportunistically collected presence-only data and site-occupancy data from planned surveys. These models also account for survey bias and imperfect detection through the use of a hierarchical modelling framework that separately estimates the species–environment response and detection process. This is particularly helpful for conservation applications and predictions for rare species, where data are often limited and prediction errors may have significant management consequences. Despite this potential importance, ISDMs remain largely untested under a variety of scenarios. We performed an exploration of key modelling decisions and assumptions on an ISDM using the endangered Baird’s tapir (Tapirus bairdii) as a test species. We found that site area had the strongest effect on the magnitude of population estimates and underlying intensity surface and was driven by estimates of model intercepts. Selecting a site area that accounted for the individual movements of the species within an average home range led to population estimates that coincided with expert estimates. ISDMs that do not account for the individual movements of species will likely lead to less accurate estimates of species intensity (number of individuals per unit area) and thus overall population estimates. This bias could be severe and highly detrimental to conservation actions if uninformed ISDMs are used to estimate global populations of threatened and data-deficient species, particularly those that lack natural history and movement information. However, the ISDM was consistently the most accurate model compared to other approaches, which demonstrates the importance of this new modelling framework and the ability to combine opportunistic data with systematic survey data. Thus, we recommend researchers use ISDMs with conservative movement information when estimating population sizes of rare and data-deficient species. ISDMs could be improved by using a similar parameterization to spatial capture–recapture models that explicitly incorporate animal movement as a model parameter, which would further remove the need for spatial subsampling prior to implementation.

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Densidad poblacional del tapir centroamericano (Tapirella bairdii) en bosque mesófilo de montaña en Totontepec Villa de Morelos, Oaxaca, México

Cited by 6 publications

References 21 publications

Using a novel model approach to assess the distribution and conservation status of the endangered Baird's tapir

Using a novel model approach to assess the distribution and conservation status of the endangered Baird's tapir

Tapirs in trouble: estimating Baird's tapir densities in the Sierra Madre de Chiapas, Mexico

A Sensitivity Analysis of the Application of Integrated Species Distribution Models to Mobile Species: A Case Study with the Endangered Baird’s Tapir

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