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

Background: Rivers and their associated vegetation are considered highly complex natural systems representing high biodiversity areas that work as biological corridors. Nevertheless, riparian vegetation of the Monarch Butterfly Biosphere Reserve (MBBR) has not been studied nor considered in the reserve’s management program. Questions: Which is the composition, structure, diversity, and state of conservation of the riparian vegetation of the MBBR? Study site and dates: The Senguio Microbasin, part of Sierra Chincua Priority Terrestrial Region, within the MBBR, in central México. 2016-2017. Methods: Using high-resolution imagery from 2014, we identified five joint categories in relation to the protection status (Core Zone, Buffer Zone, and Influence Area) and land use (conserved forest, highly disturbed forest, and farmland). We sampled three sites per category (N = 15) to analyze the composition, richness, and α- and β-diversity of the riparian communities. Results: We registered 108 species, 46 genera, and 18 families, of which 98 % are native and 2 % exotic. Richness and α-diversity were not significantly different among sites, but the composition and β-diversity showed significant differences depending on land use. The riparian vegetation is well conserved both in the Reserve´s Core and Buffer zones, and preserves high coverage, species richness, and individuals’ abundance. Conclusions: The riparian vegetation of the Senguio Microbasin hosts a biodiversity richness critical for the ecosystem’s health and evidences the relevance of considering the human use of the riparian systems to succeed in the conservation strategies.

Background: The genus Randia L. (Rubiaceae) is native to Americas and highly distributed in tropical areas. Some Randia species are used in traditional medicine in some countries to treat diverse illnesses/symptoms of kidney, circulatory system, lungs, diabetes, cancer, inflammation, and against the bites/stings of snakes and other poisonous animals. Questions: What are the phytochemical compounds previously identified in Randia? What biological activities do they present? Data description: Twenty-eight studies on chemical composition and biological activities of Randia were reviewed. Species names were corroborated in Plants of the World Online and World Flora Online. The site and studied years: Studies of Randia of Americas from 1991 to 2021. Methods: Database reviewed were PubMed, Scopus, Scielo, BVS, DAOJ, Science Direct, Springer Link, Web of Science, and Google Scholar, employing the keywords Randia and its synonym Basanacantha. Results: Six species are the most studied (R. aculeata, R. echinocarpa, R. ferox, R. hebecarpa, R. matudae, and R. monantha). Ethnopharmacology information of 12 species was recovered. One hundred compounds in Randia have been identified (phenolic acids, terpenes, sterols, and others), and diverse biological activities reported in 24 studies (e.g., antimutagenic, antioxidant, and antivenom) have demonstrated for nine species. Conclusions: Biological activities found in some species of Randia support their traditional uses, but only the antivenom effect of Randia aculeata has been demonstrated. Randia species could be a source of bioactive compounds; however, knowledge must be expanded to demonstrate their traditional uses and contribute to the development of strategies for their preservation and rational use.

Background: Germination characteristics of grasses are the bases for explain possible adaptation to environmental changes, as well as invasive behavior. Hypotheses: Each species has germination characteristics that can explain its establishment success in grassland.  Studied species: Bouteloua curtipendula, B. dactyloides, B. eriopoda, B. gracilis, B. hirsuta, B. repens, B. rigidiseta,Chloris virgata, Digitaria californica, Eragrostis curvula, E. echinochloidea, E. lehmanniana, E. superba, Heteropogon contortus, Hilaria mutica, Leptochloa dubia, Melinis repens, Muhlenbergia emersleyi, M. macroura, M. rigida, Pappophorum bicolor, and Pennisetum ciliare (16 native species and six exotic species). Study area and dates: Chihuahuan desert grasslands, 2019. Methods: Germination test at 28 °C at constant moisture and in the dark. Response variables were number of seed germinated, time of germination and length of root and shoot. Based on those, range, time, velocity, index of germination ad root:shoot ratio were calculated. Results: Germination range was ≤ 4 days on 18 species. The highest values (P < 0.05) were 7.8 germinated seed per day and 3.3 of germination index. Eleven species had a value ≤ 1 of R:S at one week age. Conclusions: E. curvula, B. curtipendula, L. dubia, and D. californica showed one or more adaptations that place them with potential for a rapid establishment in arid zones. However, the invasive aliens E. lehmanniana and Melinis repenspossibly have other strategies that facilitate their establishment.

Background: Argemone ochroleuca is a worldwide invasive weed but is also highly valuable for their chemical compounds. Knowledge about its reproduction will help create plans for its control or its propagation. Questions: Does A. ochroleuca has an incompatibility system like other Papaveraceae species? Which are the reproductive strategies that favor the seed formation in A. ochroleuca? Studied species: A. ochroleuca is an annual species with bisexual flowers. Study site and dates: Mexico City, Mexico. The fieldwork was performed from February to May in 2013, 2014, and 2017. Methods: Direct observations were made to describe the flower cycle of A. ochroleuca. We used self-pollinated flowers to analyze if this species is self-incompatible by following the pollen tube growth through gynoecium. Controlled pollinations were made to quantify and compare the number of seeds produced per treatment to know the mating system and explore if the species presents a mechanism of reproductive assurance through autogamy, or exhibits inbreeding depression. Results: A. ochroleuca is self-compatible and exhibits a mixed mating system. Although outcrossing is how more seeds are produced, both autogamy and pseudocleistogamy are present as reproductive assurance mechanisms. Naturally pollinated flowers produce the maximum number of seeds, but inbreeding depression is present in the population. Thus, the number of seeds will be affected by continuous selfing. Conclusions: This study highlights the mixed mating system and reproductive assurance mechanisms as successful strategies for A. ochroleuca, a common pattern in invasive weeds.

Background: The alteration of the carbon reservoir stored in vegetation, imply the modification of biogeochemical cycles. The change of land use and cover (CUCS) is one of the main drivers for these alterations. As a consequence of the primary activities occurring in arid/semiarid lands, carbon reservoirs are continually modified. The limited information and heterogeneity of these environments increase the uncertainty regarding the effects on carbon dynamics consequence of CUCS. The development of new methodological approaches, such as the incorporation of aerial high-resolution RGB (red/green/blue) imagery analyses, will allow extensive and continuous monitoring of carbon in arid zones. Questions: Is it possible to estimate aboveground carbon stock using RGB images obtained by Unmanned Aerial Vehicles? Site and years of study: Subtropical scrub and buffel grassland communities, located in the central Sonora, Mexico. August-October 2019 and 2020. Methods: a) In situ woody vegetation censuses were carried out to estimate carbon stock in aerial biomass (ACBA) using allometric equations (direct method), b) ACBA was calculated, using allometric equations and vegetation metrics obtained from aerial RGB images. Results: The introduction of buffel grassland implies the reduction of woody individuals, therefor, a decrease in ACBA. In total, the scrub contains 10.35 Mg C/ha, and buffel grassland around 3.20 Mg C/ha. There are correlation and significance between direct and indirect methods. Conclusions: Establishing buffel grassland reduces the ACBA, up to 70 %. The use of RGB images allowed us to estimate ACBA in arid zones.

Background: Agave ellemeetiana (A. sect. Choritepalae) features soft and “spineless” leaves and occurs in two disjunct and ecologically differentiated populations classified as subspecies. An incidental look at the flowers of A. ellemeetianassp. subdentata unveiled that these did not match those of A. ellemeetiana s. str. nor those of sect. Choritepalae. Questions: Do these disjunct populations differ in flower and fruit morphology? Do they belong to the same section within Agave? Hypotheses: The floral morphology of populations of Agave ellemeetiana ssp. subdentata from western Oaxaca places this species in A. sect. Inermes, and the set of qualitative and quantitative differences is sufficient to recognize it as a distinct species. Studied species: Agave ellemeetiana, Agave pedunculifera. Study site and dates: Putla District, western Oaxaca, December 2011 and April 2014. Methods: We conducted an alpha-taxonomic study of the Agave ellemeetiana species complex, involving two fieldwork expeditions, review of literature, online images, and herbarium specimens. Results: Differences in flower, fruit and vegetative morphology and habitat support the segregation of the populations (from the Putla District, Oaxaca) from the Agave ellemeetiana complex as a new species, A. rosalesii spec. nov. The presence of an evident corolla tube places the proposed taxon close to A. pedunculifera and within A. sect. Inermes. Conclusions: The populations from the Putla District are sufficiently distinct in their morphology and ecology to merit recognition as a new species, Agave rosalesii, placed in A. sect. Inermes. Translate stop   Translate stop  

Background: There is limited information to predict the direction in which canopy modification affects the microbial carbon use efficiency (CUE) and, consequently, the magnitude and stability of litter decomposition in monodominant sacred fir (Abies religiosa) forests. Questions: What is the effect of tree stratum alteration on CUE and stability of litter decomposition in an A. religiosaforest? Study sites and dates: Two conditions inside a sacred fir forest were selected: A) a naturally monodominant homogeneous condition, and B) a heterogeneous condition with a non-monospecific tree stratum derived from local disturbances (wildfire and reforestation) occurred on a single occasion 18 years ago. Methods: In each condition (homogeneous and heterogeneous), the Importance Value Index (IVI) was calculated in the tree stratum, while chemical composition, microbial carbon (C) concentration, enzyme activities and C mineralization were measured in litter samples. The specific enzymatic activity and the metabolic quotient were calculated as CUE indicators, and the coefficient of variation as a proxy for litter decomposition stability. Results: A change in tree species composition and an increase in tree species richness in the heterogeneous condition was found, which decreased litter phosphorous (P) concentration. This promoted a high microbial activity and low CUE, favoring C mineralization. Furthermore,  low stability during litter decomposition was observed as tree species richness increased. Conclusions: Tree stratum heterogeneity, as a consequence of past disturbances, decreases CUE and the stability of litter decomposition in an A. religiosa forest.

Background: Direct seeding of native species can be a good alternative in terms of benefit / cost for restoration in semi-arid ecosystems. In these cases, it is essential to have data on the germinability, percentage and mean germination time to define strategies that ensure a sufficient and timely quantity of plant. Questions and / or Hypotheses: Does the germinability and mean germination time of representative seeds of the Mexican Altiplano change, in a period of two years? What percentage of germination does each species present? Studied species: Frankenia gypsophila, Machaeranthera pinnatifida, Muhlenbergia villiflora, Scleropogon brevifolius, Dasyochloa pulchella and Zinnia anomala. Study site and dates: Grasslands of the RTP El Tokio and the Forest Sciences Faculty Labs from 2017 to 2019. Methods: The germinability of seeds was evaluated, by means of germination tests, of six species of the grasslands of the RTP El Tokio, after zero, eight, 24 and 27 months of field collection. Results: Only one species (Frankenia gypsophila) remained viable after 27 months and by that date its germination percentage was three times lower with respect to the first two dates. All the evaluated species presented t50 values lower than seven days. Conclusions: The percentage and mean germination time of the studied species will allow estimating the number of seeds required to obtain the desired density in a sowing for restoration purposes. The results suggest that these species are not suitable for preservation in an ex-situ seed bank stored under semi-controlled environmental conditions.

Background: The Sayula sub-basin located in the center-south of the state of Jalisco, presents a complex landscapemade up of different plant communities along an altitude gradient. Despite the fact that there are different studies in the area, they have not addressed the distribution of the vegetation along this gradient, nor its bioclimatic interpretation. Questions: What is the bioclimatic diagnosis of the sub-basin? What are the bioclimatic belts and how are they linked to their corresponding natural potential vegetation? What are the floristic bioindicators of each bioclimate belt? Study species: Vascular plants, types of vegetation. Site and years of study: The Sayula sub-basin; 2017 to 2020. Methods: Literature review, field work, bioclimatic analysis and desk work. Results: The area belongs to the Tropical Macrobioclimate, recognizing the Tropical Xeric and Tropical Pluviseasonalbioclimates; the first includes the Semi-arid Thermotropical, Dry Thermotropical and Dry Mesotropical bioclimatic belts, and the second includes the Subhumid Mesotropical and Humid Mesotropical bioclimatic belts. The mentioned categories were worked on in a GIS obtaining a cartography that showed their spatial distribution. Likewise, thegeobotanical information was synthesized in a representative vegetation chain and in tables that link the floristic, vegetational and bioclimatic information. Conclusions: The bioclimatic diagnosis allowed to establish the distribution of the bioclimatic belts as well as their relationshipwith the types of vegetation. The changes in terms of physiognomy, structure, composition and ecology of the belts are in line with the variations of the bioclimatic conditions along the altitudinal gradient. Translate stop  

Background: Coffee breeding programs in Ecuador have information on production and disease tolerance in many genotypes; however, they lack physiological information, especially on photosynthetic characteristics and their response to drought. Questions: Whether high genetic variability among coffee genotypes will explains the photosynthetic and production differences expected? Will the physiological response to the dry season (DS) be different between genotypes? Studied species: Coffea arabica L. Study site and dates: Pichincha canton, Manabí province, Ecuador during March-April 2017 (rainy season, RS) and June-July 2017 (DS). Methods: Leaf relative water content (RWC) and gas exchange of 21 coffee genotypes were measured during DS and RS. Coffee production during a period of three years was evaluated. Results: Significant differences were found in RWC, photosynthetic rate (A), stomatal conductance (gs) and water use efficiency (WUE) among genotypes, between seasons, an interaction effect of genotype × season. Drought caused a significant reduction in A and gs of 30 and 44 % respectively, while WUE was not affected. A positive linear relationship was found between A and gs, and a negative relationship between A and the leaf-air vapor pressure gradient (DW) and between gs and DW. Differences in coffee production were found among genotypes. Conclusions: The high genetic variability of C. arabica genotypes may explain the significant differences in RWC and gas exchange and interaction genotypes x season, suggesting a differential response of each genotype to drought. Eleven of the 21 coffee genotypes were sensitive to drought, but showed different responses, suggesting possible genotypic differences in tolerance. Translate stop   Translate stop