De Chiapas Research Articles

The distribution of reptile species richness in protected areas of Chiapas, Mexico

Around 19–22% of reptiles worldwide are in danger of disappearing. This problem also occurs in Mexico, particularly in Chiapas, which boasts the second-highest number of recorded reptile species in the country. To address this issue, we conducted a study to determine how natural areas can help to protect these reptiles in the state. We compiled a database of 217 reptile species in Chiapas to create Species Distribution Models (SDMs). We analyzed representativeness, beta diversity, and species richness. Our findings showed a high level of representativeness for the records and species distribution models. By stacking the maps with the total number of endemic and threatened species, we identified two hot spots for the study area, i.e., the Northern Highlands, the Central Depression, and the Sierra Madre de Chiapas. Based on the SDMs, we found more endemic and threatened species within protected natural areas than outside of these. Our study can help prioritize conservation efforts in little-studied protected areas and reaffirm the importance of conservation in areas such as the Biosphere Reserve Selva El Ocote, home to a diverse range of endemic and threatened species.

Teaching spanish to migrants in the Soconusco region, Chiapas, Mexico

This research was conducted in the state of Chiapas, throughout the Soconusco region. Students from BA in English Language Teaching at UNACH (Universidad Autonoma de Chiapas) participated as teachers in basic Spanish courses for the migrant population, from January 2020 to April 2021. This paper aims to give an account of the partial results of a study; its main objective is to analyze the nature of teaching Spanish to migrants and people in mobility from different countries. Migratory movements are a phenomenon of special incidence in contemporary societies according to the Manifest of Santander (2009), one of the first works carried out in Spain in terms of language teaching to migrants and refugees. Given the need to incorporate the teaching of the target language into the global policies of care for immigrants, since their learning of the target language depends a lot on the active insertion in the host community (Manifest of Santander cited in Garcia et al. 2014). The Language school at the UNACH is a public educational institution with social responsibility that has collaborated with COMAR (Comisión Mexicana de Ayuda a Refugiados) and the United Nations High Commissioner for Refugees (UNHCR) seeking to protect the rights and welfare of refugees, migrants and people in mobility during their stay in Mexico. Thus, the Language School has carried out the implementation of teaching basic Spanish courses as a foreign language to refugees and migrants from countries such as Haiti, Surinam, the United States, Jamaica, Switzerland, Saudi Arabia, and Canada. However, due to the COVID-19 contingency, these courses were changed from face-to-face sessions to virtual mode during that period and after the contingency, the courses had been taught in face-to-face sessions again. In this sense, this research yields interesting contributions that can be taken into account for a significant teaching-learning process of Spanish as a foreign language or as a second language in the region of Soconusco answering the following research questions: What is the training of teachers who teach Spanish as a second language in the Soconusco region? What difficulties did they have while teaching Spanish as a second language? How effective were Spanish classes for migrants and refugees?

Nature tourism and space production. Case study in an indigenous community in the region of los Altos de Chiapas

Este artículo analiza la producción del espacio turístico en la comunidad Río Arcotete del municipio de San Cristóbal de Las Casas, Chiapas. Se muestra el proceso mediante el cual los gobiernos federal y estatal de Chiapas han creado las condiciones para que una comunidad indígena que adolece de una crisis agrícola y con una pluriactividad acentuada se involucre en los servicios turísticos. Los resultados muestran que bajo las condiciones que impone el mercado turístico, los indígenas se han apropiado de esta actividad productiva, lo cual ha generado una dinámica de cambios intracomunitarios que fortalecen sus ingresos, pero a condición de una dependencia cada vez mayor del turismo. El reto que ahora tiene la población originaria es cumplir con las circunstancias que el mercado implanta, lo cual la debilita y genera una lenta maduración del destino turístico. La investigación es cualitativa basada en fuentes primarias y trabajo de campo.

The distribution of amphibian species richness in protected areas of Chiapas, Mexico

Due to the current environmental crisis, many animal species face extinction problems. Amphibian populations have been affected by this crisis. Our goal is to study amphibian species diversity in Chiapas, which has 7.6% of the endemic amphibians in Mexico and 53 protected areas. Only 58% of the protected areas have management plans or information on their resident amphibians. We aim to determine the extent of protection provided by the network of natural areas for the conservation of amphibian species in the state and to discuss the effectiveness of this protection. Therefore, we compiled a georeferenced database of 112 amphibian species in Chiapas to create each distribution model. In addition, we carried out representativeness, beta diversity, and species richness analyses. As a result, we obtained a high degree of representativeness for the records and species distribution models. However, we found a decrease in the richness of amphibians involving 20% of total species, 13% of endemics, 18% threatened according to NOM-059, and 31% threatened according to IUCN between 1800 and 2020 and 1980–2020. We also identified two biodiversity hotspots in the Sierra Madre de Chiapas and the Northern Highlands physiographic regions. Finally, based on potential distributions, we found more endemic and threatened species outside protected natural areas than inside them. Our results give a broader picture of how amphibian richness is distributed in Chiapas. This information can help to prioritize conservation efforts toward those areas rich in threatened or endemic species, such as the Northern Mountains Hotspot we identified in northern Chiapas.

Spathiphyllum frailescanense (Araceae), a new species from Sierra Madre of Chiapas, Mexico

During fieldwork conducted between 2020 and 2022 in the Sierra Madre of Chiapas, we discovered a previously undescribed species of Spathiphyllum. It is morphologically similar to S. matudae, but differs in having shorter petioles, lanceolate or elliptic-lanceolate blades, sometimes subovate, fewer pairs of primary veins per side, stipitate spadix and its pistils constricted between the ovary and the style. Here, we describe and illustrate S. frailescanense, a new species of Araceae from the Sierra Madre de Chiapas, Mexico.

Characterization of the understory associated with a pine-oak forest in the Sierra Madre de Chiapas region

Objective: To characterize the understory species associated with a pine-oak forest in the Sierra Mariscal region, Chiapas.
 Design/methodology/approach: Six 40 m2 subplots were established to evaluate the cover, abundance and identity of shrub, herbaceous and sapling components of the understory. Floristic diversity was determined. The level of disturbance was evaluated using the observation method. An analysis of variance and comparison of means by Tukey (p<0.05) between structural variables was applied. The relationship between disturbance levels and study sites was performed by correspondence analysis.
 Results: The understory is composed of five tree species, three herbaceous and two shrub species. The largest diameter (p≤0.0001 and F=27.6) corresponds to herbaceous Cortaderia seolloana (5.38±0.94 cm) and Petiridium aquilinum (4.5±0.96 cm). The greatest height corresponds to Quercus sp. saplings (126.3±75.9 cm) and the herbaceous Cenchurus sp. (110.2±54.1 cm) and Peteridium aquilinum (91.7±40.9 cm), the latter having the highest density (4050 ind. ha-1) and cover (16.2%). Floristic diversity was low in all six sites. Site six was the most diverse and site three the most disturbed.
 Study limitations/implications: The study comprised a limited and insufficient area to generalize the conditions of pine-oak forests in the Chiapas highlands. It is suggested to expand the study universe and increase the number of replications.
 Findings/conclusions: Variability in understory structure and composition was found that corroborates the relationship between forest diversity and disturbance.

Uso y conservación de plantas medicinales obtenidas de agroecosistemas y ecosistemas por los grupos étnicos Mochó y Kakchikel del sureste de Chiapas, México

Even though the ethnic groups Mochó and Kakchikel of the Sierra Mariscal, Chiapas, Mexico, have formal medical services, they still preserve and use medicinal plants. This research had the aim to identify their conservation practices, by using ethnographic and ethnobotanical methods with direct interviews, participatory observation and a questionnaire; furthermore, a Jaccard ́s similarity index for plant species was estimated. Both groups (97% each) use medicinal plants for various reasons and obtain them mainly from their agroecosystems. Within the Kakchikel territory, 53% are native plants, 43% introduced, while 4% does not have a report; within the Mochó territory 56% are native plants and 44% introduced ones. The similarity index showed 0.33 of shared taxonomic species within both territories (33 out of 131 of total). The Kakchikel use more conservation practices than the Mochó ethnic group, to have their medicinal plants ready available, mainly from their agroecosystems.

Consumption of arthropods by hummingbirds in the Sierra Madre de Chiapas, Mexico

An organism's morphological features can determine the type of prey they consume due to adaptive advantages in capturing them, for example, the shape and length of the bill in birds. Hummingbirds have been considered specialists in nectar consumption. However, they have been documented to also be important insectivores in ecosystems. In this study, we evaluated arthropod consumption by hummingbirds in relation to their bill and capture strategies. We theorized that hummingbirds with short-medium bills (9-11 bill length to body mass cube root ratio) capture a higher proportion of non-flying arthropods, as they have a lower linear speed of closure of the bill tip relative to the base, while species with long bills (13-14) capture mainly flying arthropods. The study was conducted in El Triunfo Biosphere Reserve, Chiapas, southeastern Mexico from 2015 to 2016, where seven hummingbird species that captured arthropods, their strategies of capture, and the type of prey consumed were recorded. We also analyzed the stomach contents (n = 72 stomachs) collected in the Sierra Madre de Chiapas. We calculated the frequency of occurrence of arthropods and their diversity, as well as the breadth of the feeding niche and the bill-prey relationship of 15 hummingbird species. The Green-throated Mountain-gem ( Lampornis viridipallens) and Rivoli's Hummingbird ( Eugenes fulgens) presented the highest richness of arthropod consumption. Arthropod prey belonged to eight orders, where Hymenoptera and Diptera were the most frequent. The most recorded capture strategies were on the substrate in sustained flight (37.5%) and hovering in sustained flight (33.3%). A positive association was found between the type of arthropods consumed and the morphological traits of the hummingbirds, non-flying arthropods were captured by hummingbirds with short-medium bills, while hummingbirds with long bills captured flying arthropods. Morphological adaptations for food resource use are a trait that determines food selection, capture, and handling success.

Biotic regionalization of freshwater fishes in Northern Middle America highlights high beta diversity created by prominent biogeographic barriers

Northern Middle America (NoMA) is considered a transition zone between the Nearctic and Neotropical biogeographic realms. In this region, Nearctic and Neotropical freshwater fishes create regional faunas of mixed origin, but their general biogeographic patterns have not been quantified. To identify such patterns, we delineate biogeographic regions (BRs) and major biogeographic barriers of NoMA and summarize patterns of faunal similarity among BRs. We used clustering analysis on a presence-absence matrix of primary and secondary freshwater fishes to group 97 level-6 HydroBASINs units spanning NoMA into BRs. We assessed statistical support of clusters using one-way analysis of similarity and implemented a species-indicator analysis. We delineated biogeographic barriers with the software Barrier 2.2 and determined faunal similarity among BRs using beta diversity-Jaccard dissimilarity and producing a minimum-spanning tree. Seven statistically distinctive and geographically coherent BRs were delineated and described. Barrier analysis identified three major barriers within NoMA. The first barrier combines the Sea of Cortés (Gulf of California) and Sierra de Juárez-Cerro Gordo highlands. The second combines the Trans-Mexican Volcanic Belt, Sierra Madre del Sur, and Sierra Madre de Chiapas highlands. The third combines the Río Grande Rift, Sierra Madre Occidental, and Mesa Central highlands. Faunal dissimilarity was very high among BRs, with lowest dissimilarity (92%) between the Balsas-Nacaome and Grijalva-Usumacinta BRs. Boundaries of NoMA BRs do not correspond with political boundaries. We concluded that bioregions of NoMA are faunally distinct, with limited overlap due to presence of strong, long-standing geographical barriers enhanced by aridity in the North.

Chytrid prevalence and infection intensity in treefrogs from three environments with different degrees of conservation in Mexico

AbstractChytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has been related to rapid population declines and extinction in amphibians around the world. Bd has been associated with a severe decline in amphibian populations in southern Mexico. We compare the prevalence and intensity of Bd infection in two tree frogs in southern Mexico with similar life habits (Plectrohyla matudai and Ptychohyla euthysanota), inquiring if they differ across habitat types with different degrees of disturbance: preserved cloud forest, secondary cloud forest and anthropized riparian vegetation, and across three seasons. We examine the relationship between infection prevalence and intensity with biotic and abiotic variables. Infection prevalence differed between the two species, but not among environments, despite their similar life habits. Among seasons, prevalence decreased significantly at the end of the rainy season. There was no indication of significant changes in infection intensity between species, environments, and seasons. Moreover, the interaction among extrinsic factors (canopy cover, temperature, relative humidity) and factors intrinsic factors (body condition) explains the dynamics of Bd infection in the region. In our sample, we found no disease‐affected individuals, which may indicate that both species are resistant to the effects of the pathogen under field conditions. Finally, our results found no evidence to indicate that open canopies and anthropized habitats of the Sierra Madre de Chiapas are a refuge that prevents high prevalence or infection of Bd in stream breeders' amphibians.Abstract in Spanish is available with online material.

Late Cretaceous–Miocene depositional evolution of Chiapas, Mexico: A foreland controlled by collision of Greater Antilles arc and the subsequent relative migration of the Chortís Block

New U–Pb and “double dating” (U–Pb and U–Th)/He) age determinations on detrital zircons from Upper Cretaceous–Miocene formations greatly improve our understanding of both evolutionary and clastic provenance models for southern Mexico and the western Caribbean. Samples from the Méndez, Ocozocoautla, Angostura, Tenejapa, Soyaló, El Bosque, San Juan, Nanchital Shale, Nanchital Conglomerate, Huamelula, and Ixtapa units in the western Sierra de Chiapas, Mexico, consistently indicate a south-to-north transport of clastic detritus from orogenic headlands into the Chiapas Foldbelt Basin and, presumably, the Sureste Basin (Gulf of Mexico). However, this interpretation is partly guided by 1) palinspastic reconstructions of the Chortís Block and fault slices of the North America–Caribbean plate boundary that restore to paleo-positions south of Oaxaca and Chiapas states and western Guatemala, and 2) published fission track data that indicate the Chiapas Massif was not a significant sediment source or barrier until the late middle Miocene. In addition, zircon data on volcanic breccias (magmatic?) from cores of supposed Cretaceous and Paleogene levels of the Salina Cruz wells indicate that today’s Gulf of Tehuantepec forearc is likely the “western tail” of the Chortís Block and represents a displaced segment of the Guerrero Arc of western Mexico. Analyses of key thin sections and one heavy mineral sample complete the data set. We find that Pacific-origin Caribbean models provide the necessary inferences for meaningful interpretation of our data, and, conversely, that our data on the various depositional units through time iteratively help to support Pacific-origin models. For example, our data from Chiapas supports 1) arc collision to the south in the Maastrichtian (Greater Antilles), and 2) the existence of Paleogene orogenic highlands south of the Chiapas Massif, interpreted here as the paleo-North America–Caribbean plate boundary zone.

Potential Distribution and Connectivity for Two Plethodontid Salamanders: Conservation Areas and Landscape Corridors for Two Endemic Species of México and Guatemala.

Habitat loss is one of the most important threats to biodiversity; it alters the habitat connectivity of species and is among the main causes of the global amphibian extinction crisis. Identifying the potential areas of distribution and connectivity of species is of the utmost importance so that informed decisions can be made for the conservation of vulnerable amphibian populations. In this study, we performed species distribution models and used circuit theory to model omnidirectional connectivity for two plethodontid salamanders of conservation concern distributed in the forests of Chiapas, Mexico, and Guatemala (Bolitoglossa franklini and Bolitoglossa lincolni). Potential distribution maps show an affinity for well-preserved montane forests for both species. Likewise, we found that the niches of the species are not similar. The connectivity models show that the main areas of connectivity are in the Meseta Central de Chiapas, Sierra Madre de Chiapas, and the Cordillera Volcánica Guatemalense, in this last range, important areas of connectivity were located, as well as least-cost paths and barriers to the movement of both species. We identified that important areas of climatic suitability and connectivity are not within the protected natural areas and may be threatened by the increasing influence of anthropogenic activities. The results of our study show the importance of preserving the regional forests to ensure the persistence of species with arboreal habits and high sensitivity to habitat transformation, as well as to recognize and prioritize potential areas for management and protection in both southern Mexico and Guatemala.

Regional patterns of vegetation, temperature, and rainfall trends in the coastal mountain range of Chiapas, Mexico

Changes in atmospheric CO2, ocean temperature, and regional vegetation conditions in Mesoamerica indicate that significant trends in temperature and rainfall may have occurred in the Sierra Madre de Chiapas, Mexico. This is an important region for flora and fauna which could be affected by climate trends. We aimed to determine if and where climate trends had occurred in the Sierra Madre and lower elevation regions between 1990 and 2016 (27 years), if these trends were part of longer term (1960-2016 [57 years]) changes, and how changes in large-scale and regional/local conditions may be influencing these trends. In the Sierra Madre, overall minimum daily temperatures increased, maximum temperatures decreased, and the most significant mean temperature trends were cooler during the 27-yr period. Both the start and end of the wet season trended earlier in the year, and wet season rainfall increased significantly. Trends were not significant during the 57-yr period in the Sierra Madre; however, in the adjacent Pacific coast region, significant warmer temperature trends continued during this period. Within regions, there was large variation in temperature and rainfall changes and some local trends were opposite to the regional averages. Large-scale processes of warming sea surface temperatures in the east coast of Mexico, a change from the positive to negative phase of the Pacific Decadal Oscillation and increases in atmospheric CO2 may be influencing these trends. At the regional scale, increases in dense vegetation and evapotranspiration since 1990 may have created characteristics favoring a positive feedback of higher ocean-based moisture and vegetation-based precipitation cycling.

Amphibian areas of endemism: A conservation priority in the threatened Mexican cloud forest

Amphibians of the Mexican Cloud Forest have a great diversity but are highly threatened. Forest endemisms are useful for recognizing biodiversity hotspots; furthermore, the interaction of historical and current events has generated areas of endemism that can be used for biological conservation in forest fragments; therefore, their identification is an essential part of the management and planning of biological conservation. Thus, our objective was to identify areas of endemism in the cloud forests of Mexico through the analysis of geographical distribution of 126 species of amphibians, as well as their conservation status to obtain information that supports the selection of priority areas for conservation. For this, the endemicity analysis method was used with three spatial scales, 1°×1°, 0.5°×0.5° and 0.25°×0.25° (lat/long), to achieve more complete results and avoid visual overrepresentation of areas of endemism. Seventeen consensus areas distributed in four of the five provinces of the Mexican Transition Zone were identified. The province of the Sierra Madre del Sur exhibited the highest amount of endemism areas, followed by the Sierra Madre Oriental, the East of the Trans-Mexican Volcanic Belt, and the Altos de Chiapas. Results indicate that the endemic areas of the Sierra Madre Oriental and Sierra Madre del Sur provinces are composed of amphibians included in the IUCN red list and the Official Mexican Standard NOM-059. Thus, the small areas of endemism in eastern and western Sierra Madre del Sur, nested within larger ones may be used to increase the protected areas of cloud forests in Mexico.

NIVEL DE ADOPCIÓN DE TÉCNICAS SILVOPASTORILES EN LA SIERRA MADRE DE CHIAPAS, MEXI

<p><strong>Background</strong>. Silvopastoral systems are viable agroforestry option to move toward sustainable livestock and rural development. <strong>Objective</strong>. to analyze the level of adoption of silvopastoral techniques by beneficiary producers of three converging projects in the Sierra Madre de Chiapas region (Mexico), during the 2008-2017 period. <strong>Methodology</strong>. Forty-two Cattle Production Units (UPP, for its acronym in Spanish) from the municipalities of Villaflores, La Concordia and Pijijiapan (Chiapas) were diagnosed by socioeconomic and technical variables. A Silvopastoral Systems Development Index (IDESSP, for its acronym in Spanish) was used to evaluate their level of adoption. <strong>Results.</strong> The global IDESSP of UPP was 52%. UPP in the “High” level of adoption reached an IDESSP of 74% (± 6.2), “Medium” an index of 56% (± 5.3) and located in the “Low” group was 42% (± 3.1). The socio-educational characteristics (age of the producer, years of experience in livestock activity, education level) and the productive variables (land area, herd size, milk production / day, annual income) were different (P <0.05) between the groups. The significant variables (P> 0.001) that allowed a greater adoption of silvopastoral practices were the average annual income of each family, the availability of total land, and the collaboration that the rancher had with other social sectors. <strong>Implications</strong>. The low adoption of silvopastoral techniques encourages the continuation of conventional livestock practices with negative effects on natural resources, diminishes the capacities for strengthening and social organization, and limits the processes of scaling-up or massification of SSP. <strong>Conclusions.</strong> The level of adoption of silvopastoral techniques among the UPP was intermediate, which was subject to availability of land, years of experience, educational level and number of links for the production of each owner of the production units, the area under actions of conservation were greater than silvopastoral techniques.</p>

Género y exotismo en la representación turística: las casas/tiendas en Zinacantán, Chiapas

This article analyses the exotic and idealizsd images of indigenous women in tourism. In particu‑ lar, it reflects on the role of gender in the construct of imaginaries and the representation of femininity asso‑ ciated with the traditional roles of women in the private and domestic sphere. To this end, the author inves‑ tigates the tourism scenario in the houses/shops of the municipality of Zinacantán, in Los Altos de Chiapas, Mexico, and the criteria of authenticity as deployed in tourism promotion. The paper aims to investigate this view of female exoticism that affects the way these women redefine themselves through the staging of their bodies and their traditional roles. It concludes that this image of exoticism reproduces a colonial gaze and perpetuates patriarchal power relations and ideologies.

Evaluation and accreditation from the perspective of university students: An educational experience at the Universidad Autónoma De Chiapas

This work is the result of an investigation developed in the Universidad Autónoma de Chiapas, which is born of the interest that exists on the part of members of the Academic Board for Policy, Management, Education and Diversity (CA) to the need to know the impact they have had evaluation processes and accreditation level in schools and in the University. In this context, it is essential to know the opinion of the writers who are directly involved with the results obtained in each of the educational programs that have been subjected to these processes and have achieved their accreditation. Methodologically, the study has a tendency towards critical social paradigm, with a mixed approach (qualitative and quantitative) where the opinion of the university through interviews, in other case, is recovered through analysis of surveys of the university community, Given the specific weight that each of the actors in the process of evaluation and accreditation of each of the educational programs was essential to know the view of the university authorities responsible for the management of faculties and the heads of the coordination of evaluation and accreditation; For this, a series of interviews with those who occupied strategic positions in the administration were made; that is, those who have access to information regarding such processes. This work is approached from four categories: 1) Public Policy, 2) Management, 3) organization and 4) Results and Impact. In the specific case of this paper, it only discloses the results in the category of public policy and its indicators: assessment, accreditation and Norming.

Potential distribution of Croton guatemalensis : a model with reproductive biology data

Background: The inclusion of information on the phenology of any given species can significantly improve the resulting of potential distribution models. Scientific literature does not provide up-to-date information on the abiotic and biotic factors that determine the distribution of Croton guatemalensis , a species native to communities in south Mexico. For the first time, the potential distribution of C. guatemalensis was determined using a model which includes reproductive biology data.
 Questions: Which bioclimatic and climatic variables most contribute to the distribution of C. guatemalensis ? Does reproductive biology data contribute significantly to the prediction of the species distribution?
 Studied species/Mathematical model: Croton guatemalensis / Maximum Entropy Modeling
 Study area and dates: Chiapas, Mexico, January - December 2020.
 Methods: The MaxEnt 4.4.4 algorithm was used, incorporating 16 variables, including bioclimatic, climatic and elevation. In addition, a habitat suitability layer was built.
 Results: The model presented a precision of AUC = 0.964 ± 0.004. Eight variables contributed to explain 86.5 % of the potential distribution of the species. According to their contribution to the model, the most important were the seasonality of precipitation, habitat suitability, elevation and April solar radiation. The species was found in the physiographic regions Central America South Mountain Range Subprovince, Central Depression of Chiapas Discontinuity, and Altos de Chiapas Subprovince.
 Conclusions: The inclusion reproductive biology data of C. guatemalensis contributed to improve the model. This information allows the development of more effective management and conservation plans by identifying the precise regions in which the species is found.

Optimal fertilization dose in castor bean (Ricinus communis L.) using partial budgets analysis

Objective: To determine the economically adequate fertilization dose for a castor bean (Ricinus communis L.) crop that improves the producer's benefits using the partial budgeting technique.
 Design / methodology / approach: The experiment was established at a site located 500 m from the Centro de Chiapas experimental field, with an altitude of 800 m. Two production factors were studied: nitrogen (40, 60, and 80) and phosphorus (20, 40, and 60) with three levels each. The treatments had nine combinations in a randomized complete block experimental design and four replications. Phenological and morphological variables, seed yield, and variable costs economic components were evaluated as a response.
 Results: With the average yields the obtained net benefits were determined; an adjustment of the benefits was made, and its dominance was determined. Four experiments were dominated, and five showed favorable profits for the producer. The 80-60-00 formulation had a return rate (RR) of 23 %.
 Conclusions: The 40-20-00, 40-40-00, 40-60-00, 80-40-00 and 80-60-00 formulations were dominant. The 80-60-00 formulation reported the highest RR, an increase in variable cost of US$9.64, like other doses of lower costs and benefits. For this dose, the net benefits increase was us$ 222.61.

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

AbstractSpatial 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.