Tuxtlas Region Research Articles

Participatory wildlife films for primate conservation education in Los Tuxtlas Biosphere Reserve, Veracruz, Mexico

Abstract Audiovisual media has become an integral part of conservation education strategies, with the potential not only to communicate information but also to impact on its viewers perceptions and attitudes towards a particular subject. Despite this potential, few studies have evaluated either the use of film for primate conservation initiatives or the wider impact of participatory film production. Our study evaluates the impact of a participatory documentary film about historic human-primate coexistence in the Los Tuxtlas region, Veracruz, Mexico, to improve people’s knowledge, perception, and attitudes towards the local primate species, Alouatta palliata and Ateles geoffroyi. Our study took place in six rural localities, in four of which a participatory film-making process was undertaken, involving production workshops and public screenings; two localities were intentionally left out as control groups. People’s knowledge, perception, and attitudes towards primates were assessed through randomized sampling using a questionnaire prior (n = 419) and following (n = 223) the presentation of the documentary. Results indicate a minimal but positive shift in participant’s attitudes and perceptions, with statistically significant increases in primate knowledge scores. While the participatory approach offers promise, further exploration and refinement are essential for effective conservation education. The study highlights the need for diverse and locally based perspectives in developing conservation education materials and programs to foster meaningful engagement and drive primate conservation efforts forward.

Coccoloba burkeae and C. najarroi, two new species of Coccoloba sect. Coccoloba (Polygonaceae) from Mexico

Background: Coccoloba is a Neotropical genus of trees, shrubs, and lianas with approximately 150 species. Reviwed Mexican specimens of Coccoloba do not correspond to any recognized species within the genus, so they are proposed as new species.
 Question: What are the morphological characteristics that differentiate the two new species from other Coccolobaspecies? What is its distribution and conservation status?
 Studied species: Species of Coccoloba sect. Coccoloba endemic to Mexico.
 Study site and dates: Chiapas and Veracruz, Mexico, 2022-2023.
 Methods: All available information for Coccoloba, including herbarium specimens and online databases, was reviewed. Subsequently, a comparative analysis was carried out including the two new species proposed and the recognized species in the genus. Geographic distribution maps were prepared and the conservation status of the new species was determined, following the IUCN guidelines.
 Results: Coccoloba burkeae and C. najarroi are described and illustrated as new species. Both are endemic to Mexico. C. burkeae is distributed in the humid forests of the Tuxtlas region in Veracruz and is morphologically similar to C. barbadensis, C. hondurensis and C. spicata; this species is considered in the Endangered (EN) category. C. najarroi is restricted to the humid forests of Chiapas and is similar to C. ascendens and C. ibarrae. This species is considered Critically Endangered (CR).
 Conclusions: The morphological characteristics of the fruit, the inflorescence and the leaves are important to diagnose the two new species of Coccoloba; both being endemic to Mexico.

A new species of Gonolobus (Apocynaceae) from Veracruz, Mexico

Gonolobus sanmartinus is herein described and illustrated from the state of Veracruz, Mexico. It is an endemic species to the Los Tuxtlas region and similar in foliar features to those of G. pallidus. However, the faucial ring and gynostegial corona are remarkably different. This new species shares its distribution with G. ancorifer, G. fraternus, G. niger and G. versicolor, and a dichotomous identification key for these species in the Los Tuxtlas region is included. The new species’ relationship with other species is discussed and a geographic distribution map is presented, as well as its conservation status.

Diversity of insects associated with the fruits of four tree species of Lauraceae from Los Tuxtlas region, Mexico: an annotated and illustrated taxonomic list

Besides recruitment and dispersal, fruits are key resources for the maintenance of insect communities. This study is focused on the insects inhabiting the fruits of 4 wild Lauraceae species. Although the trees of this family are important elements of tropical forests, their interaction with insects, especially in association with fruits, remains poorly studied in wild tree species. Our study aims to characterize the diversity of insects associated with fruits of Damburneya ambigens, Damburneya gentlei, Damburneya salicifolia, and Nectandra turbacensis, in the rainforest of Los Tuxtlas, Veracruz. We present an illustrated taxonomic list of species, annotated with a comprehensive review of the insects’ natural history and their interactions with Lauraceae species. We reared 54 insect species from approximately 6,500 fruits, some of which represent potential new species and records for Mexico. Insect species diversity was high and differed between Lauraceae species. The reared insects comprise a wide variety of distributional ranges, feeding types, and habitats. This research provides novel information about the interactions among insects and fruits of Lauraceae and the complexity of their trophic networks in tropical rainforests. Furthermore, it evidences the importance of wild fruits as resources for insect communities.

EVIDENCE OF ANTIBODIES AGAINST DIFFERENT Leptospira spp. SEROGROUPS AND FACTORS ASSOCIATED WITH ITS PRESENCE IN SHEEP FROM VERACRUZ, MEXICO

<p class="Default"><strong>Background</strong>. Leptospirosis is a bacterial zoonosis caused by pathogenic species of the genus <em>Leptospira</em> that affects mainly reproductive performance in sheep. <strong>Objective</strong>. To identify the seroprevalence of <em>Leptospira </em>spp., associated serogroups, and possible risk factors in the state of Veracruz, Mexico. <strong>Methodology</strong>. Blood samples were collected from 405 sheep in 55 farms located in 13 municipalities distributed along three ovine-producing regions in the state. Serological diagnosis was made by Microscopic Agglutination Technique (MAT). The prevalence and its confidence intervals (CI) were calculated using Vassarstats software, the Odds Ratio (OR) values were estimated with WinEpiscope. <strong>Results.</strong> An overall seroprevalence of 53.83% (<sub>95%</sub>CI:48.84-58.75), per municipality of 100% (<sub>95%</sub>CI :71.66-100) and per flock of 92.73% (<sub>95%</sub>CI: 81.58-97.65) were noted. The highest prevalence by region was 58.82% (<sub>95%</sub>CI<sub>:%</sub>:50.57-66.62) for Los Tuxtlas (p= 0.218) and per municipality 86.36% (<sub>95%</sub>CI:71.95-94.33) for Ángel R. Cabada. The predominant serogroup was Hardjo (45.93%; <sub>95%</sub>CI:41.02-50.92). By age, the highest values were 55.93% (<sub>95%</sub>CI:48.29-63.31) in the group of 19-36 months. The main recognized risk factors were region and municipality. Los Tuxtlas Region (OR =1.92; <sub>95%</sub>CI:1.08-3.43) and the municipalities of Ángel R. Cabada (OR=15.5; <sub>95%</sub>CI:5.1-47.2), Ayahualulco (OR=10.1; <sub>95%</sub>CI :3.6-28.7), and Coatzintla (OR=6.1; <sub>95%</sub>CI: 30.3 – 95.0).<strong> Implications. </strong>This study explores the presence of antibodies against <em>Leptospira</em> spp. in sheep, its associated serogroups and risk factors in the state of Veracruz, Mexico. This is this first report on the presence and relevance of this infection in sheep of this region. The role of sheep as a maintenance host for <em>Leptospira</em> spp. in endemic areas is stressed. <strong>Conclusions. </strong>The study concludes that <em>Leptospira</em> spp. in sheep has an overall seroprevalence of 53.83% in the state of Veracruz, Mexico and several serogroups present.</p>

Two new species of the braconid wasp genus Bracon (Braconinae) from Los Tuxtlas region in Veracruz, Mexico, reared from fruits of three species of Lauraceae.

Two new species belonging to the braconid genus Bracon (Braconinae) are described from the tropical rainforest of Los Tuxtlas in the state of Veracruz, Mexico, B. laurae sp. nov. and B. rosamondae sp. nov. These species are morphologically similar and were reared from fruits of three Lauraceae species, Damburneya ambigens, D. salicifolia and Nectandra turbacensis. However, comparison of their DNA barcoding locus and a fragment of the nuclear ribosomal 28S gene confirmed their allospecificity. These two species share a number of morphological features with the two described Neotropical Bracon species that are known to be phytophagous (seed predators), B. phytophagus Quicke and B. zuleideae Perioto Lara. We therefore propose a new species-group for the above four species, the B. phytophagus Quicke species-group, and suggest that the two newly described species also have a phytophagous feeding strategy.

Geochemistry of marine sediments adjacent to the Los Tuxtlas Volcanic Complex, Gulf of Mexico: Constraints on weathering and provenance

The provenance of GoM45 and GoM63 core sediments recovered in the deep-sea area (∼1666 m–1672 m water depth, respectively), in front of the Los Tuxtlas volcanic field, Gulf of Mexico was analyzed based on the textural, mineralogical, and geochemical variations. The radiocarbon age data of Globorotalia menardii group foraminiferal species varied from 17,709 to 20,711 calibrated years B.P for the sediment core GoM45, which represent Pleistocene/Holocene boundary. The core sediments were characterized by detrital components with enriched SiO2, Al2O3, and Fe2O3 concentrations. The weathering indices like Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), and Plagioclase Index of Alteration (PIA) revealed a low intensity of weathering for the core sediments.The V/Cr, Ni/Co, Cu/Zn, and V/Cr elemental ratios indicated an oxic depositional environment for the Gulf of Mexico deep sea area. In addition, the geochemistry data indicated a passive margin setting, which is consistent with the geology of the Gulf of Mexico. The trace and rare earth element concentrations, and Eu anomaly indicated that the sediments were derived from the natural erosion of andesitic and basaltic rocks in the Los Tuxtlas region, SW Gulf of Mexico. Los Tuxtlas region is partly influenced by the Papaloapan and Coatzacoalcos Rivers, which discharges into the SW Gulf of Mexico.

Clasificación de los murciélagos de la región de los Tuxtlas, Veracruz, respecto a su respuesta a la fragmentación del hábitat

I propose three types of bat species according to their response to habitat fragmentation in Los Tuxtlas region: Type I (habitat dependent), Type II (vulnerable), and Type III (adaptable). Effects of habitat fragmentation on bat genetic structure will be primarily patent on Type I bats, and the major effect will be observed at long term.

El ecoturismo como estrategia de fortalecimiento en las acciones de conservación ambiental: Un análisis regional en Los Tuxtlas, Veracruz, México

The Los Tuxtlas region in the South of the state of Veracruz is privileged by a diversity of aspects of its ecology and landscape, result of its volcanic geomorphology and its tropical climate, which allows the presence of mesophilic forests and humid forests. These forests provide numerous ecological services to the local populations and hold a great biodiversity, of importance on a national scale. Therefore, in 1998 under federal decree the Los Tuxtlas Biosphere Reserve was created, whose objective was to incorporate the inhabitants of this area in conservation strategies, through different mechanisms, including ecotourism. The present research analyses the contributions and impacts of this activity in terms of environmental conservation, considering ethnographic methods and a cartographic representation, which assist in the understanding of the activity’s territorial composition.

Regional Ecotourism Networks: Experiences and Lessons from Los Tuxtlas, Mexico

Ecotourism has the potential to foster human development in marginalised areas and, at the same time, promote environmental conservation. However, as studies have shown, ecotourism enterprises often struggle to be economically viable. In this context, cooperation and the establishment of networks on a regional scale have been proposed as promising strategies, which can benefit the enterprises in many ways, including information exchange, effective promotion, creation of competitive tourism products and representation of common political interests. Based on a mixed-method approach, the present investigation analyses to what extent this has been the case in the Los Tuxtlas region in Southern Mexico, where since the year 2000 several attempts have been made to form regional ecotourism networks. Mapping and the use of quantitative network analysis tools, based on the application of questionnaires, demonstrate the current structure of both formally established networks and the net of informal cooperation in the region. In combining these data with qualitative information obtained from interviews, insights are gained regarding the catalysts that initiate networking processes and the stakeholders involved, the main obstacles as well as costs and benefits of forming part of regional networks.

High Richness of Vascular Plants in the Tropical Los Tuxtlas Region, Mexico

We present an assessment of the recorded vascular plants in the Los Tuxtlas region, in the state of Veracruz, Mexico, an important portion of the humid tropical forest at the northern edge of its distribution. A literature review and the information contained in the two most important databases in Mexico with digitized information for the region report 2,548 species, of which 2,391 are native and 157 naturalized (exotic). The families with the highest number of species are Fabaceae, Orchidaceae, Asteraeae, and Rubiaceae. The composition of the flora is analyzed, and its similarity is compared with other tropical regions of Mexico. The humid tropical forest in Los Tuxtlas stands out as the site with the third highest number of tropical species in Mexico, and in particular for its high number of endemisms. A quarter of the species occurring in the region are threatened; despite this, the biosphere reserve within its limits plays an important role in the conservation of this type of vegetation.

Life history and past demography maintain genetic structure, outcrossing rate, contemporary pollen gene flow of an understory herb in a highly fragmented rainforest.

IntroductionTheory predicts that habitat fragmentation, by reducing population size and increasing isolation among remnant populations, can alter their genetic diversity and structure. A cascade of effects is expected: genetic drift and inbreeding after a population bottleneck, changes in biotic interactions that may affect, as in the case of plants, pollen dynamics, mating system, reproductive success. The detection of the effects of contemporary habitat fragmentation on the genetic structure of populations are conditioned by the magnitude of change, given the few number of generations since the onset of fragmentation, especially for long-lived organisms. However, the present-day genetic structure of populations may bear the signature of past demography events. Here, we examine the effects of rainforest fragmentation on the genetic diversity, population structure, mating system (outcrossing rate), indirect gene flow and contemporary pollen dynamics in the understory herb Aphelandra aurantiaca. Also, we assessed its present-day genetic structure under different past demographic scenarios.MethodsTwelve populations of A. aurantiaca were sampled in large (4), medium (3), and small (5) forest fragments in the lowland tropical rainforest at Los Tuxtlas region. Variation at 11 microsatellite loci was assessed in 28–30 reproductive plants per population. In two medium- and two large-size fragments we estimated the density of reproductive plants, and the mating system by analyzing the progeny of different mother plants per population.ResultsDespite prevailing habitat fragmentation, populations of A. aurantiaca possess high genetic variation (He = 0.61), weak genetic structure (Rst = 0.037), and slight inbreeding in small fragments. Effective population sizes (Ne) were large, but slightly lower in small fragments. Migrants derive mostly from large and medium size fragments. Gene dispersal is highly restricted but long distance gene dispersal events were detected. Aphelandra aurantiaca shows a mixed mating system (tm = 0.81) and the outcrossing rate have not been affected by habitat fragmentation. A strong pollen pool structure was detected due to few effective pollen donors (Nep) and low distance pollen movement, pointing that most plants received pollen from close neighbors. Past demographic fluctuations may have affected the present population genetic structure as Bayesian coalescent analysis revealed the signature of past population expansion, possibly during warmer conditions after the last glacial maximum.DiscussionHabitat fragmentation has not increased genetic differentiation or reduced genetic diversity of A. aurantiaca despite dozens of generations since the onset of fragmentation in the region of Los Tuxtlas. Instead, past population expansion is compatible with the lack of observed genetic structure. The predicted negative effects of rainforest fragmentation on genetic diversity and population structure of A. aurantiaca seem to have been buffered owing to its large effective populations and long-distance dispersal events. In particular, its mixed-mating system, mostly of outcrossing, suggests high efficiency of pollinators promoting connectivity and reducing inbreeding. However, some results point that the effects of fragmentation are underway, as two small fragments showed higher membership probabilities to their population of origin, suggesting genetic isolation. Our findings underscore the importance of fragment size to maintain genetic connectivity across the landscape.

Plant Use by Artisans Within the Los Tuxtlas Biosphere Reserve, Southern Mexico

Throughout Latin America, the manufacture of handicrafts for sale is an important economic resource for many indigenous and non-indigenous groups. The construction of many of these items involves the use of various parts of a diverse range of plant species found in remaining tropical rain forest areas. It is important to obtain information on the species used and to assess the impact of this activity on the native flora and fauna of these areas. Studies in tropical areas such as Nicaragua, Panama, Colombia, Brazil and India have documented the traditional use of plants and the effects on forest conservation and management (Santana et al. 2001; Shaanker et al. 2004; Runk et al. 2004; Cadena-Vargas et al. 2007; Frausin et al. 2008; Toribio et al. 2009; Estupinan-Gonzales and JimenezEscobar 2010; Gonzalez-Perez et al. 2013). Mexico is well known for its high biological-cultural diversity (Bye et al. 1993; De Avila 2008; Llorente-Bousquets and Ocegueda 2008). Along with this cultural diversity a broad selection of natural resources are used in the manufacture of handicrafts throughout the country. An inventory of plant and animal species used by artisans throughout Mexico documented 541 species of plants and 125 animal species (Bravo and Lopez 1999). A later study focusing on tropical areas of Mexico documented 58 species of plants used in the state of Veracruz (Cruz et al. 2009). However, for the Los Tuxtlas region, while there are accounts of medicinal plant use for some ethnic groups, little attention has been given to plant use in artisanal products (Leonti et al. 2003). The Los Tuxtlas rain forest region in the southeastern portion of the state of Veracruz on the Gulf of Mexico has long been exposed to anthropogenic activities with a marked acceleration of colonization in the 1950s in many rural areas by people from other parts of the country (Guevara et al. 1997). Two remaining ethnic groups (Nahuatl and Popoluca) are found in the extreme southern portion of the region. However, in 1998 through a multi-institutional effort an area of 155, 200 ha was declared a UNESCO Biosphere Reserve known as Reserva de la Biosfera Los Tuxtlas (hereafter RBLT). The geographical location is between 18°05′; 18°45′ N and 94°35′; 95°30′ W. Today, there is a high level of population living in several urban centers and about 273 rural communities within the boundaries of the RBLT. The main economic activity is cattle ranching and agriculture. The remaining protected rain forest is found in three distinct areas and encompasses 29,720 ha. One of the main tasks of the federal government agency (CONANP/SEMARNAT) responsible for the management and conservation programs of this biosphere reserve is to address the many social and economic problems of the region by means of developing and implementing strategies to enhance local conservation awareness and encourage sustainable development in rural communities, as well as to provide economic alternatives for the rural population. One of the strategies adopted has been to provide workshops and training courses in various non-indigenous communities in the manufacture of handicrafts for sale in local markets and tourist * Armando Aguirre armando.aguirre@inecol.mx

Seed predation in a human-modified tropical landscape

Abstract:Contemporary defaunation of fragmented forests potentially alters patterns of seed predation and dispersal. Alternatively, the remaining fauna may compensate for missing animals, resulting in equivalent rates of seed dispersal and predation. In the Los Tuxtlas region of southern Mexico, populations of large terrestrial fruit-eating mammals are diminished or absent from many forest remnants. This study reports fruit removal and seed predation patterns of Poulsenia armata (Moraceae), in forest fragments and a continuous forest (LTBS). Contrary to expectation, we found no differences in seed predation (mean ± SD) between LTBS (7.2 ± 1.8 seeds per station) and forest fragments (5.6 ± 1.1). However more fruits were removed in the LTBS (11.4 ± 0.9 fruits per station) than in forest fragments (8.1 ± 0.8). Animal activity, recorded by camera traps, differed between animal guild with fewer seed dispersers in forest fragments (mean = 0.43 ± 0.02 photos wk−1) than in the LTBS (mean = 0.68 ± 0.05). Fruits and seeds attracted many species of mammal (n = 12) in both habitats, indicating substantial redundancy. Remnant forest patches in the Los Tuxtlas landscape retain great ecological value, both as refuges for mammals and habitats for trees, such as P. armata.

Guadua tuxtlensis (Poaceae: Bambusoideae: Bambuseae: Guaduinae), una nueva especie inadvertida de la región de Los Tuxtlas, Veracruz, México

Se describe e ilustra Guadua tuxtlensis , una especie nueva de la región de Los Tuxtlas, de los Municipios de Catemaco y San Andrés Tuxtla, Estado de Veracruz, México. Guadua tuxtlensis se caracteriza por tener culmos huecos con espesores de las paredes del culmo gruesas, ramas con espinas desde el primer nudo, hoja caulinar basalmente persistente, con conspicuas aurículas falcadas-fimbriadas, vaina foliar apicalmente fimbriada, lamina foliar ovoide-lanceolada y adaxialmente muy nervada. En este estudio se presenta una comparación de la morfología vegetativa entre G. tuxtlensis , G. aculeata y G. inermis , y se incluye una clave de las especies del género Guadua para México.

Effects of forest fragmentation on the recruitment success of the tropical tree Poulsenia armata at Los Tuxtlas, Veracruz, Mexico

Abstract:Recruitment success of individual plants is limited by an array of biotic and abiotic factors. Seedling survival may experience high mortality due to negative density dependence or altered microclimatic conditions. This study reports regeneration of Poulsenia armata (Moraceae), in the fragmented landscape of the Los Tuxtlas region in south-eastern Mexico. Density, survival and growth of seedlings (<1 y) and juveniles (<150 cm height) of P. armata were predicted to be significantly lower in forest fragments compared with extensive continuous forest. Contrary to expectation, density did not vary between habitats; however, we found twice the number of seedlings (n = 82) in forest fragments than in the continuous forest (n = 35). Forest fragments were associated with higher seedling densities close to adult trees. Unexpectedly, we found no evidence for negative density dependence in plant survival or growth. Survival and growth of P. armata were negatively impacted in forest fragments, with desiccation by warmer daily temperatures likely the cause of mortality, independent of density. Of the 111 individuals recorded in 2010 in forest fragments, 38% died over 2 y of census (n = 42), while 9% (n = 12) of the 127 individuals from the continuous forest died. Higher rates of mortality suggest that conditions in forest fragments are detrimental to seedling cohorts over time. Low juvenile recruitment jeopardizes persistence of P. armata, in fragmented populations of this rain-forest tree.

Diversidad y distribución de Marcgraviaceae en México

The neotropical family Marcgraviaceae includes about 140 species of woody climbers. The objectives of this study are to review the diversity of the Marcgraviaceae in Mexico, to map and analyze the current and potential distribution of each species occurring in Mexico. Therefore, a review of 221 collections in 15 national and 9 foreign herbaria was conducted. The modeling of the potential distribution was performed with the Maxent software, using the geographic coordinates of the specimens reviewed plus 19 environmental variables. We recorded Marcgravia brownei, M. mexicana, M. nepenthoides, M. stonei, Ruyschia enervia, Souroubea exauriculata and S. loczyi subsp. loczyi. We also present the first record of M. pittieri for Mexico. The species are distributed in Chiapas, Oaxaca, Puebla, Tabasco, and Veracruz, where they mainly occur in tropical lowland forest and cloud forest. Los Tuxtlas region, the Sierra Norte de Oaxaca, and eastern Chiapas can be considered of high importance for the conservation of the family in Mexico. Despite the alarming rate of destruction of their natural habitats, we consider that none of these species need to be classified under any of the IUCN categories due to their number of occurences in Mexico and other neotropical countries.

Morphological characterization of extrafloral nectaries and associated ants in tropical vegetation of Los Tuxtlas, Mexico

Extrafloral nectaries (EFNs) are glands that produce sugary exudates and can be located in any vegetative or reproductive structure of the plant. The EFNs occur in different locations on the leaves, stems, inflorescences and flowers (but are not directly involved with pollination). Occurrence of EFNs on plants of coastal vegetation, tropical rain forest and cloud forest in southern Mexico was studied within Los Tuxtlas Biosphere Reserve, Veracruz. We focused on determining the identity and species richness of plants with EFNs, and describing EFNs morphologies. We found 50 species of plants with EFNs (16 families, 31 genera), which corresponds to approximately 5% of the flora reported for the field site (943 species). Trees were the life form with the greatest representation of EFNs while shrubs and epiphytes had the least representation. EFN-bearing plants were particularly well represented in the families Fabaceae, Euphorbiaceae, Convolvulaceae, Bignoniaceae, Malpighiaceae, Passifloraceae, Costaceae, Tiliaceae, while eight other families had only one species. We found six different types of EFNs according to their morphological structure. Dissimilarity analyses between plants and ant species showed that the forest in the Los Tuxtlas region has a rich array of ant species associated with EFNs, with a low niche overlap of ant species. This diversification in ant use of EFNs is of particular interest from an ecological and evolutionary perspective (potential mutualisms with adaptative value), but this deserves still further studies in detail. The present study shall provide basic information for future research in these fields of plant–animal interactions in neotropical vegetation.

Deep divergences and extensive phylogeographic structure in a clade of lowland tropical salamanders

BackgroundThe complex geological history of Mesoamerica provides the opportunity to study the impact of multiple biogeographic barriers on population differentiation. We examine phylogeographic patterns in a clade of lowland salamanders (Bolitoglossa subgenus Nanotriton) using two mitochondrial genes and one nuclear gene. We use several phylogeographic analyses to infer the history of this clade and test hypotheses regarding the geographic origin of species and location of genetic breaks within species. We compare our results to those for other taxa to determine if historical events impacted different species in a similar manner.ResultsDeep genetic divergence between species indicates that they are relatively old, and two of the three widespread species show strong phylogeographic structure. Comparison of mtDNA and nuclear gene trees shows no evidence of hybridization or introgression between species. Isolated populations of Bolitoglossa rufescens from Los Tuxtlas region constitute a separate lineage based on molecular data and morphology, and divergence between Los Tuxtlas and other areas appears to predate the arrival of B. rufescens in other areas west of the Isthmus of Tehuantepec. The Isthmus appears responsible for Pliocene vicariance within B. rufescens, as has been shown for other taxa. The Motagua-Polochic fault system does not appear to have caused population vicariance, unlike in other systems.ConclusionsSpecies of Nanotriton have responded to some major geological events in the same manner as other taxa, particularly in the case of the Isthmus of Tehuantepec. The deep divergence of the Los Tuxtlas populations of B. rufescens from other populations highlights the contribution of this volcanic system to patterns of regional endemism, and morphological differences observed in the Los Tuxtlas populations suggests that they may represent an undescribed species of Bolitoglossa. The absence of phylogeographic structure in B. nympha, in contrast to the other widespread species in the subgenus, may be due to historical forest contraction and more recent range expansion in the region. Phylogeographic data provide substantial insight into the evolutionary history of these morphologically similar species of salamanders, and contribute to our understanding of factors that have generated the high biodiversity of Mesoamerica.

Forecasting cloud forest in eastern and southern Mexico: conservation insights under future climate change scenarios

Assuming that co-distributed species are exposed to similar environmental conditions, ecological niche models (ENMs) of cloud forest species were developed to study how climate change could affect the distribution of cloud forest in eastern and southern Mexico for the year 2050. Using ENM-based predictions and climatic data for IPCC climate change A2 and B2 scenarios, we observed 54–76% reduction of the cloud forest, mainly in the northern region of its current range (Sierra Madre Oriental) and the Pacific slope of Chiapas. With predicted 2050 climate change, cloud forest in the Los Tuxtlas region and El Cielo Biosphere Reserve may face a serious threat of extinction due to the observed upward migration to higher elevations. Our results add to recent studies detecting negative impacts of climate change in montane forests, but the negative impacts of climate change might be exacerbated by current environmental changes in the region. The integration of ecological-niche characteristics of cloud forest in conjunction with projections of extreme climate scenarios constitute a suitable tool to define appropriate areas in which proactive conservation and management strategies should be focused.