Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

En la actualidad las actividades antrópicas han provocado un incremento en la disponibilidad de nutrientes en bosques tropicales, con efectos negativos sobre la diversidad y funcionamiento de estos ecosistemas. Se analizó los efectos de la adición en el suelo de nitrógeno (N), fósforo (P), nitrógeno más fósforo (N+P) y un tratamiento control sin fertilizar (Con) sobre la diversidad taxonómica y funcional de briófitos epífitos en un bosque montano de la Región Sur de Ecuador. Se registró la riqueza y composición en 320 cuadrantes de 20 x 30 cm de un total de 80 árboles. Los efectos de los tratamientos sobre la diversidad taxonómica y funcional se evaluaron mediante modelos lineales generalizados mixtos y los cambios en la composición de las comunidades con análisis multivariados. Un total de 59 especies de briófitos fueron registradas en el bosque montano. Los resultados indicaron que no hay efectos de la adicción de nutrientes en suelo sobre la riqueza, riqueza funcional y composición de briófitos epífitos, sin embargo, el diámetro de los árboles fue un factor limitante para los briófitos. Los tratamientos con nutrientes en bosques tropicales montanos no estuvieron relacionados con la riqueza, composición y diversidad funcional de briófitos, sin embargo, los rasgos del hospedador (DBH) fueron factores limitantes.

Phenology is one of the main ecological aspects when it comes to silvicultural and agroforestry management. However, phenological knowledge of forest species is still scarce and fragmented, mainly in the tropics. Cinchona pubescens Vahl. presents limited phenological information, so the objective was to evaluate the phenology of the species C. pubescens Vahl. in two forest ecosystems (silvopastoral system and secondary forest) located in Pucará Alto, Intag area, Imbabura, for the period April 2018 - May 2020. Individuals of C. pubescens were characterized and selected according to phenotypic characteristics. Phenological monitoring was carried out with Fournier's semiqualitative method. The average index (PI) and weighted percentage of phenophases were calculated. The foliation was present throughout the year in an intense manner in both ecosystems. Flowering occurred once a year, in the period January-May in both ecosystems with an intense massiveness. Fructification for silvopastoral system occurred intensely in the period August-November with its maximum in October and for secondary forest with medium massivity in the period September-December with its maximum in November.

Background: Our study presents the first assessment of the relationships between environmental heterogeneity and the palm community at the landscape scale at the northern boundary of tropical rainforest distribution in America. Question: How does landscape-level heterogeneity (edaphic, topographic as well as the density, diversity, and tree biomass) shapes the palm community in a protected reserve affected by defaunation? Study site and date: The study was carried out in Los Tuxtlas Tropical Biology Station, Veracruz, Mexico (2020). Methods: We delineated landscape units (LUs) based on soil and geomorphology to characterize the biophysical mosaic. We built rank-abundance curves to compare the palm richness and their abundance among LUs. Permutational multivariate analysis of variance (PERMANOVA) and nonmetric multidimensional scaling (NMDS) were applied to detect shifts in the palm community across LUs. Results: Integrating abiotic and biotic components by delimiting LUs allowed us to evaluate the multifactorial effect of environmental heterogeneity on the palm community. The density and composition of the palms changed significantly among the LUs, influenced by soil coarse fragments, elevation, slope inclination, and annual precipitation. Tree richness and density had a significant effect on the palm community only when analyzed in combination with the soil-topography variables. Conclusions: The results reveal that there is high edaphic and topographic heterogeneity that influences palm species distribution at the landscape scale. The environmental heterogeneity approach allows capturing novel abiotic variation to explain the distribution patterns of palm species and their coexistence in highly diverse tropical communities.

Background: Abies hidalgensis is an endemic species from Hidalgo sate, Mexico, listed on the IUCN Red List in the VuD2 category. It has been confused with A. guatemalensis in some population where there is roundwood extraction reported as A. religiosa, which generates confusion on the taxonomic identity of species distributed and being harvested in Hidalgo. Questions and / or Hypotheses: What species or species of the Abies genus are distributed and harvested in Hidalgo, Mexico? What is the geographic distribution of A. hidalgensis? Studied species: Abies hidalgensis, A. religiosa. Study sites and dates: Municipalities of Acaxochitlan, Acoculco, Agua Blanca de Iturbide, Epazoyucan, Mineral del Monte, Pachuca, Singuilucan, Tenango de Doria, Tepeapulco and Zimapan, in Hidalgo state. Years 2015 to 2017. Methods: Eighteen morphological characters were analyzed by discriminant function analysis. Genetic differentiation was estimated from the analysis of three microsatellites developed for A. guatemalensis. Results: Abies hidalgensis is distributed to the southeast and A. religiosa is in the central-southern zone of Hidalgo. The distinctive morphological characters are: resin ducts, shape of the apex and morphological characters associated with the ovulate cones and seeds. Genetic studies showed that Abies sp. have greater divergence and genetic diversity with respect to A. hidalgensis and A. religiosa. The inbreeding coefficient is higher in A. religiosa. Conclusions: Two species of the Abies genus are distributed in the state of Hidalgo, Mexico.

Background: Beekeeping is an alternative for sustainable production in Sierra del Abra Tanchipa Biosphere Reserve region. Knowing richness of melliferous flora, its distribution and flowering season, improves its management. Questions: Which are the species of melliferous flora in the surrounding landscape of the Reserve? Which is its origin, growth form, floral resource, phenology and distribution? How is species richness in natural areas and disturbed areas? Study site and period: Influence area of Sierra del Abra Tanchipa Biosphere Reserve, San Luis Potosí, Mexico, between August 2020 to March 2022. Methods: Melliferous flora species were collected monthly in bee foraging radius of six apiaries, in different types of vegetation. Data was taken from growth form, origin, floral resource offered, and phenology. Species richness and composition were compared between vegetation types from natural and disturbed areas. Results: 191 melliferous species were recorded; 91 nectariferous, 16 polliniferous and 84 nectar-polliniferous. Fabaceae is the most representative family. Flowering increases in June and September, decreases in January and April. Forty nine percent of species exclusively inhabit disturbed areas, 29 % natural areas and 22 % both. In natural areas 100 % are native while in disturbed areas 14 % are introduced and 86 % native. In natural areas 70 % are trees while in disturbed areas 57 % are herbs. Conclusions: The region has a great richness of native melliferous flora. The information generated will allow beekeepers to have a better management of their hives and to value the natural areas of foraging.

Background: Many Mexican Ternstroemia species mainly inhabit the tropical montane cloud forest. These species have been misidentified in herbaria due to their morphological resemblance. Question: Are there foliar anatomical and micromorphological characters with diagnostic value that allow discriminating between the Mexican species of Ternstroemia? Study species: Ternstroemia sylvatica Schltdl. & Cham., and T. lineata DC. subsp. lineata (Pentaphylacaceae Engl.), 2018-2019. Study site and date: Tropical montane cloud forests at the Trans-Mexican Volcanic Belt and Sierra Madre Oriental. Methods: Botanical specimens were collected and removed from herbarium sheets. The leaves were prepared through cleared, dehydration and paraffin inclusion techniques to observe and describe them. Results: The Ternstroemia species showed specific features of plants in humid environments, such as thin cuticle, mesophyll with scarce parenchyma palisade, and abundant intercellular spaces in the spongy parenchyma, and specific pigments that help to capture light and serve as protection. The species share a festooned broquidodromous venation pattern, anomocytic stomata, and closed collateral vascular bundle surrounded by perivascular fibers. Both species are differentiated by leaf shape, abundance of collenchyma layers, lenght of palisade parenchyma, and number of stomata per square millimeter on the abaxial surface. Conclusions: We support and validate some features recorded for Ternstroemia species and reject some previous generalizations made worldwide to the genus. This research is the first attempt to study anatomy, architecture, and foliar micromorphology of Mexican Pentaphylacaceae.

Antecedentes: Como parte de las colectas para inventariar la Flora de Oaxaca, se realizó una exploración en el bosque mesófilo de montaña de la Sierra Norte del estado, encontrándose una planta trepadora del género Ruehssia, que no coincidía con      las demás especies del género. Preguntas: ¿La morfología de la corola, de la corona ginostegial y del fruto, así como la distribución geográfica, serán elementos suficientes que permitan distinguir especies en el género Ruehssia? Especies de estudio: Ruehssia sp. nov. Sitio y años de estudio: Sierra Norte de Oaxaca, México; 1989-2022. Métodos: A partir del material colectado y de herbario, se analizó la morfología y distribución de las poblaciones de la especie      y se comparó con taxones afines. Conforme a los criterios de la IUCN se estableció una categoría de vulnerabilidad para la especie. Resultados: Aquí se propone una especie nueva con base en el concepto cohesivo de especie. La especie es similar a Ruehssia rzedowskiana y R. calichicola, pero difiere en la morfología de la corola y la corona ginostegial, así como en su distribución. Se proporciona la descripción morfológica de la especie nueva, imágenes de los taxones tratados, un mapa de distribución geográfica y el estado de conservación. Se incluye una clave de las 18 especies de Ruehssia presentes en Oaxaca. Conclusiones: Ruehssia magalloniae se reconoce como una especie nueva para la ciencia. Este descubrimiento incrementa a 39 el número de especies de Ruehssia registradas para México, con un 58 % de endemismo.

Background: The generic boundaries and phylogenetic relationships of Clinopodium are still unstable. There are 15 species recorded in Mexico, which were also treated under the genera Calamintha or Satureja. Recent botanical explorations in western Mexico led to the discovery of an additional species which possesses relatively long corollas, reddish in color, this morphological pattern fits into the species set previously known as Satureja sect. Gardoquia. Questions: what are the diagnostic morphological characters that support the new species? Which are the species morphologically similar? Studied species: species of Clinopodium inhabiting in Mexico and those belonging to Satureja sect. Gardoquia. Study site and dates: San Sebastián del Oeste, Jalisco, Spring 2022. Methods: Botanical collects, herborization and morphological characterization of the specimens collected. Comparison with specialized literature, herbarium specimens and nomenclatural types online. Results: The new species Clinopodium haraverianum is distinguished from the other species in the genus by the combination of the following characters: herbaceous habit, stem not branched, leaves progressively reduced in size towards the apex of the stem, calyx strongly bilabiate, corollas with a tube longer than 16 mm and reddish. The most similar species is C. macrostemum, to which it is compared in the diagnosis. Conclusions: Clinopodium haraverianum is set apart from most of the species of Clinopodium by presenting the characters defining the group Gardoquia, and within this, it differs by the habit and size of floral structures. This species constitutes and addition to the endemic flora of Jalisco and consequently of Mexico.

Background: A significant number of species of grasses (Poaceae) have allelopathic properties and two genera of Andropogoneae -Cymbopogon and Bothriochloa- are the main aromatic genera recognized in the family. The genus Imperata (Poaceae: Andropogoneae) is widely distributed, with several species being present around the world. Questions and / or Hypotheses: This study assessed the allelopathic potential of some South American species of Imperata taking into account previous reports on I. cylindrica, which has been extensively studied due to its invasiveness and allelopathic potential. Studied species / data description /Mathematical model: I. brasiliensis, I. condensata, I. minutiflora, and I. tenuis Study site and dates: Greenhouse of the Instituto Multidisciplinario de Biología Vegetal, Sistemática y Filogeografía de Plantas, Córdoba, Argentina. Methods: We obtain the aqueous extract from the studied species and we evaluated its effect on germination and root and shoot growth of lettuce, corn, and tomato. Results: In bioassays, aqueous leaf extract of I. brasiliensis, I. condensata, I. minutiflora, and I. tenuis inhibited seed germination and root and shoot growth of lettuce (Lactuca sativa), tomato (Solanum lycopersicum), and maize (Zea mays). The extracts mainly affected root and shoot length, whereas the effect on seed germination was low. Conclusions: The studied species may contain allelochemicals, which interfere with seed germination and seedling growth. Future research on the type of chemical compounds present in aqueous extracts may contribute to their use for agroecological purposes.

Background: Santos Reyes Tepejillo, Oaxaca, lacks a comprehensive floristic inventory. A list of vascular plants will allow to have information to propose suitable strategies for the management and conservation of their plant resources. Questions: How many and which species of vascular plants are there in the municipality of Santos Reyes Tepejillo and in which type of vegetation are they found? What is the percentage of native, endemic and cataloged species in some category of risk? Data description: Vascular flora. Study site and dates: Santos Reyes Tepejillo, Oaxaca, Mexico; 2019 to 2021. Methods: Periodic botanical collection trips were made; the gathered material was herborized and determined with identification keys, and the information collected in field work was complemented with that available in databases and the review of specimens in herbaria. Results: A total of 536 species, 336 genera, and 103 families were recorded. The Asteraceae (58 genera/88 species), Fabaceae (21/37), and Apocynaceae (13/23) families stand out for their generic and specific richness, where the more diverse genera were Tillandsia, Salvia, and Euphorbia. Two hundred thirteen species are endemic to Mexico, 13 are exclusive to Oaxaca, and two restrict their distribution to the study area; 111 species are listed in some risk category. Conclusions: Santos Reyes Tepejillo concentrates a remarkable specific richness and presents an important level of endemism. This study documents three new records for Oaxaca and the discovery of three new species. Is essential to continue with the botanical exploration in the study area and adjacent regions.