Antonio Guerra-Pérez’s research while affiliated with Autonomous University of Tamaulipas and other places

Esta obra da a conocer el resultado de la transmisión del conocimiento tradicional de los habitantes de la Reserva de la Biosfera El Cielo sobre los nombres comunes y el uso de los árboles silvestres y naturalizados de ésta área natural protegida. Un aspecto importante fue la colecta de ejemplares botánicos para su identificación taxonómica y para respaldar la información etnobotánica obtenida, material que está depositado en la colección del herbario Francisco González Medrano (UAT). En total se registraron 318 nombres tradicionales distintos para 176 especies de árboles nativos o naturalizados, pertenecientes a 142 géneros y 63 familias de plantas vasculares. La parte principal del libro está conformada por 100 fichas sintéticas que indican el nombre común mayormente utilizado por las habitantes locales. Se incluye el nombre científico, la familia botánica y una descripción breve de las características de cada especie. Asimismo, se menciona el hábitat (principalmente el tipo de vegetación) y el uso tradicional que se le da al árbol en el área de estudio. Es importante mencionar que los nombres y usos de los árboles que se describen en este libro tienen orígenes diversos. En la mayoría de los casos son de la región, en tanto que en otros se derivan de distintas áreas del país. Una peculiaridad interesante es que frecuentemente los nombres hacen alusión al uso del árbol, a alguna característica del mismo o a su parentesco con especies cultivadas. Esperamos que los lectores de este trabajo encuentren enriquecedora esta información, resultado de la transmisión del conocimiento y el valor histórico-cultural de esta región de Tamaulipas.

Apiculture continues to grow steadily in Mexico as does interest in potential nectariferous and polliniferous flora in different states. An inventory was made of melliferous plant species in the state of Tamaulipas, Mexico, visited by Apis mellifera L. in different annual seasons. Field work was done between 2012 and 2015. Plant species whose flowers were visited by A. mellifera were documented, including data on life form, growth form, origin, resource production, vegetation type and flowering time. A total of 215 species were recorded belonging to 173 genera and 60 families of phanerogamic plants. Most are native species (87.91 %) and herbaceous (42.32 %). Fabaceae and Asteraceae are the most common families. The highest proportion of plants are nectariferous (45.12 %), followed by nectariferous-polliniferous (40 %) and polliniferous (14.88 %). Secondary vegetation and dry tropical forest contain the largest number of these species, and provide the greatest floral resources during the summer season.

Diversity and geographic distribution of cacti in the Cuatro Ciénegas Basin (CCB), in the state of Coahuila, Northeast Mexico, were assessed using the complementary index (CI) and the geographic expansion index (GEI) in order to define priority zones for conservation from January 2017 to December 2018. The study area was divided into 12 plots, each of an area of approximately 192.93 km². For each site, two rectangular plots were defined, each 1 km long and 40 m wide (i.e., a total 8 hectares of sample area per site), where cactus diversity, vegetation and soil types, and climate were recorded. Results showed the presence of 21 genera and 65 taxa including 42% and 12% of the taxa mentioned in the literature for the state of Coahuila, highlighting the richness of this area in the state. Cylindropuntia leptocaulis had the widest geographic distribution in CCB with GEI = 1.00, followed by eight taxa, whereas Echinomastus mariposensis, Echinomastus warnockii, and Epithelantha micromeris subsp. bokei had a narrower distribution with GEI = 0.1667 in CCB. Plot 3 (El Churince 1) was considered as a first priority site with a CI = 85% (55 taxa), followed by plot 2 (La Jara) with 8 taxa (CI = 8), and by site 7 San Juan with two additional taxa (CI = 3). Regarding priority sites for conservation, plot 2 (La Jara) had the highest number of threatened taxa (19) and a CI = 76%; this was followed by plot 3 (Churince 1) with 5 taxa endangered, (CI = 20%) and plot 7 was the last with only 1 taxa (CI = 4%). These plots are located in two vegetation types, the rosetophyllic desertic thornscrub and the microphyllic desertic thornscrub, with a semi-arid desertic climate (BWhw); soils include regosol, calcisol, and leptosol. Due to these environmental characteristics, CCB should be considered a hotspot zone regarding cacti species diversity in northeastern Mexico, and it is important to establish biodiversity conservation actions in the plots in CCB with the highest concentration of cacti species.

In the northeast of Mexico, the genus Abies forms forests considered relicts, with distribution only recognized by governmental instances for the state of Nuevo León. There are four species of Abies known within the state of Tamaulipas, which are listed by IUCN, but only two of them (A. vejarii and A. guatemalensis) form forests, being those found in Mexican protection categories. The use of free visualization tools and geospatial modeling allowed us to study the relict distribution of these Tamaulipan forests. We recorded ecogeographic factors from three sites in this forest, at the Field Control Points (PCC), which allowed to establish optical characteristics on satellite images of the Google Earth ™ viewer. With the values of altitude, slope and exposure, we obtained a first model (approximation model), using Boolean algebra with the Spatial Analyst module for ArcView 3.2 of ESRI ™, which was superimposed on the images of the visualizer, to adjust it and obtain a model principal. We added other points on the viewer in places where the INEGI records the presence of the forest in Nuevo León. Subsequently, the values for each of the WordlClim variables of the ten points obtained were extracted, establishing ranges that we processed through Boolean algebra; also, a cluster analysis was applied to obtain the bioclimatic similarity between the sites. The potential distribution was also superimposed on Google Earth ™ to repeat the adjustment process of the model and get the real distribution of the Tamaulipan forest. In this way, we obtained a potential area of 165.9 km2, but the actual distribution is only 3.68 km2, which represents less than 1% of the state territory. In the PCCs there are conditions of humidity and temperate temperature throughout the year, which are the product of the exposure and slope of the hillside; there, humidity depends on the altitude at the sites of the Sierra Madre Oriental, and on the proximity to the Gulf of Mexico in the forest of the Sierra de San Carlos. Which is the main differentiation variable between both sites. In addition to these conditions, other factors have allowed the prevalence of forests in Tamaulipas: they are not harvested commercially, mainly to their isolation and difficult access. Some sites of the potential distribution are occupied primarily by pine forests, but a large part of the surface has been affected mainly by fires, which means that there are chaparrals, shrubs, or induced grasslands. Because it is an isolated and relictual ecosystem, formed of species at risk and that also does not have legal protection, it can present significant levels of fragility and vulnerability, especially in the face of changing global climate conditions. Knowing their distribution provides the basis for more in-depth studies and conservation strategies appropriate to these forests. Finally, and despite the limitation of digital cartography in great detail, the geospatial tools and the method used were adequate to model the real distribution of the Abies forest in Tamaulipas, being more appropriate than the use of ecological niche algorithms, mainly due to which they depend on a high number of records.

El herbario de la Universidad Autónoma de Tamaulipas se creó como una necesidad, a partir de los primeros proyectos de investigación sobre flora y vegetación en el estado de Tamaulipas a prinicpios de los 80s. En 2017 se le puso el nombre de Francisco González Medrano" como un tributo a la memoria de este importante botánico que impulsó la formación y mantenimiento de esta colección. En la actualidad, el herbario está registrado en el IndexHerbariorum con elacrónimo UAT y cuenta con 25,000 ejemplares distribuidos en cuatro secciones: 1)Sección Fanerogámica, 2)Sección Pteridológica, 3)Sección Briológica y 4 )Sección Ficológica.

Vascular epiphytes contribute significantly to tropical diversity. Research on the factors that determine vascular epiphytic diversity and composition in tropical areas is flourishing. However, these factors are entirely unknown in tropical-temperate transition zones, which represent the distribution limit of several epiphytic species. We assessed the degree to which climatic and structural variables determine the diversity of vascular epiphytic assemblages (VEAs) in a transition zone in Mexico: the El Cielo Biosphere Reserve. We found 12,103 epiphytic individuals belonging to 30 species and 15 genera along a climatic gradient from 300 to 2,000 m a.s.l. Bromeliaceae and Orchidaceae were the most species-rich families. Forests along the windward slope of the Sierra Madre Oriental (semideciduous forest and tropical montane cloud forest) had higher species richness than forests along the leeward slope (pine-oak forest and submontane scrub). Species richness was largely determined by seasonality and, to a lesser degree, by forest structure, whereas abundance was mainly determined by host tree size. Variation in VEAs composition was largely explained by climatic variables, whereas forest structure was not as important. VEAs differed among forest types and slopes in terms of taxonomic and functional composition. For example, certain bromeliad indicator species reflected differences between slopes. Although within-tree epiphytic species richness (alpha diversity) was low in this transition zone relative to other habitats, species turnover among forest types (beta diversity) was high. These findings suggest that each forest type makes a unique and important contribution to epiphytic diversity in this transition zone.

Rhus pachyrrhachis and Rhus virens are medicinal plant species with important uses in northeastern Mexico. They belong to a complex of Rhus species called "lantriscos", which are used for medicinal applications. The medicinal effects of these species are based on traditional use, however, they require phytochemical research to validate their medicinal properties, as well as structural characterization for their correct identification during the collecting practice and uses. The phytochemical potential of aqueous extracts from R. pachyrrhachis and R. virens was analyzed by the quantification of total phenolic content (TPC), free radical-scavenging potential, and total flavonoids, with a comparison of four drying methods, and some phenolic compounds were identified. Furthermore, the stems and leaves of both species were anatomically characterized to establish a differentiation. R. pachyrrhachis and R. virens showed similar values of phytochemical contents, although the TPC content (0.17 mg of gallic acid equivalent per gram of dry weight, GAE/g DW) was higher in R. virens. The drying method used affected the metabolite contents, and this behavior was related to the species. Regarding the phenolic compounds, shikimic acid, galloylquinic acid, and gallic acid were identified in both species, however, quinic acid was only found in Rhus pachyrrhachis, while vanillic acid O-hexoside was identified only in Rhus virens. At the anatomical level, the pubescence associated with trichomes on the leaves of Rhus pachyrrhachis was highlighted as the main differential characteristic.

Capsicum annuum var. glabriusculum, is a variety of wild chili pepper belonging to the family Solanaceae and is considered as the origin for all cultivated chili species of the world. This species is an important genetic resource for agriculture and food, is widely distributed in northeastern Mexico in altitudes from 0 – 1200 m.a.s.l. This species grows mainly at low altitudes and its upper limit reaches 1000m., it prefers temperatures above 18.3O C and its production and harvest may ocurr at two seasons, one during the beginning of the summer and the main one ocurring in the middle of the autumn in northeast México. It is estimated that the main production occurs in the state of Tamaulipas with 84 tons per year and is harvested from 23 municipalities. Concentration of capseicins and dihydrocapsaicine from wild populations may vary considerably from one location to another in the municipalities, ecotypes and diverse climatic conditions from this wide geographic zone. The high demands of wild chili as well as the variability on concentration of capseicins in fruits are considered as some of the main reasons why intensive cultivation of this species should be carried out in Northeastern Mexico.