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

Background: Hybridization in nature occurs in numerous botanical families. In particular, the Cactaceae family contains lots of genera in which hybridization is reported. Questions: What are the patterns of reported natural hybridization in Cactaceae and their probable causes? Are there phylogenetic and evolutionary implications related to hybridization, particularly in Opuntioideae? Data description: A total of 62 articles about natural hybridization and classical Cactaceae literature were reviewed. Study site and dates: From 1900 to June 2021 Methods: A search for articles was performed in Web of Science and Google Scholar with the keywords "Cactaceae hybridization", for time span "1900 to 2021" and included information from classic family-specific monographs. Results: Natural hybrids in Cactaceae occur in subfamilies, Cactoideae and Opuntioideae. There is evidence of nonselective mechanisms of reproductive isolation, but only for few taxa. For Cactoideae members the main approach used was morphological description, and the tribe with the highest number of natural hybrids was Trichocereeae. In Opuntioideae, the reviewed articles performed mostly chromosome counts, morphometric and phylogenetic analyses, and showed the highest number of natural hybrids. Conclusions: It has been suggested that hybridization impacts the evolution of Cactoideae and Opuntioideae, but few studies have formally tested this hypothesis. In Cactoideae, we found only descriptive evidences of hybridization; therefore, previous statements suggesting an important role of hybridization in the evolution of Cactoideae should be supported by performing formal analyses. For the postulation that hybridization impacts the evolution of Opuntioideae, we found formal evidence supporting hybridization hypothesis unlike what we found in Cactoideae.

Background: Geographic distance promotes phenotypic variation by facilitating environmental distance, limiting gene flow, and exposing plants to different pollen vectors. Therefore, understanding how plant morphology changes across a geographic range improves our understanding of the drivers of morphological diversification both on a macro- and micro-evolutionary scale. Questions: 1) How do geographic location and abiotic factors affect flower morphology between populations? 2) Is there a geographic pattern of flower morphology variation? and 3) How does yearly variation in temperature and precipitation affect flower morphology within populations? Studied species: Penstemon albidus, P. fruticosus, P. glandulosus, P. speciosus, and P. whippleanus Study site and dates: The continental USA, summers of 2017 and 2018 Methods: Fifty-seven populations and 496 individuals were selected at random to measure ten floral traits. Bioclimatic variables were extracted from the WorldClim database and NOAA. Linear models, partial least squares regression, Mantel tests and canonical correlation analysis were used to analyze the data. Results: Geographic variables alone explained a significant portion of the variation in flower morphology in two species, while in others, flower morphology did not vary despite large geographic distances. Penstemon albidus and P. whippleanus flowers increase in size from south-north, while P. glandulosus and P. speciosus exhibited an east-west increasing trend. Additionally, mean annual precipitation was the most important variable influencing P. glandulosusflower morphology. Conclusions: Geographic distance facilitates isolation-by-distance and isolation-by-phenology as well as abiotic differences between populations; however, other factors such as pollinators might be keeping populations morphologically homogeneous despite large geographic distance.

Background: Castilla elastica is a tree known since pre-Hispanic times for its latex production. It is an emblematic species for Mexico, imminent deforestation is a threat for its survival in Mexico and Tabasco. Questions: In which ecological conditions is C. elastica distributed in Mexico? In how many areas of occupancy is it located? Studied species: Castilla elastica Cerv. Study site and dates: The Mexico and the state of Tabasco, enero-diciembre 2019. Methods: Records were obtained from different virtual sources and in herbaria, also field visits in Tabasco. The distribution points were geo-referenced, were converted to the shapefile format through the QGis 3.16.16 program. The areas of occupancy (AOO) were calculated according to the Cartographic method by conglomerates. Results: 615 records were obtained. It was found that the species is generally distributed in tropical areas of Mexico, mostly identified in Chiapas; its altitudinal range goes from 0-1,660 m. Associated with 11 soil units, forest ecosystems and agro-ecosystems. The total of the AOO consisted of 43 conglomerates and 20 satellites, which were located mainly in the Gulf of Mexico. Conclusions: Historically, C. elastica has a distribution on both sides in Mexico, prefers warm climates (A), de transition A(C) and Leptosol soils. Current records were established for Tabasco where it is found particularly in cocoa-plantations. The AO with the largest surface corresponds to Campeche, Yucatan, and Quintana Roo, coincides with the area of the Mesoamerican Biological Corridor; this work provides data on their ecological predilections that will serve for their sustainable conservation.

Background: Sinaloa is among the states with the fewest floristic studies in Mexico. Questions: What plants are endemic to Sinaloa? What areas have the highest levels of endemism? What is their ethnobotanical significance? What are the priority species for conservation? Studied species Endemic vascular plants. Study site and dates: Sinaloa, Mexico; 2018-2021. Methods: Specialized literature, herbarium specimens, and electronic databases were consulted; the field work focused on type localities and other potential distribution sites for the endemic species. A Priority Conservation Index (PCI) was designed and applied, based on ecological and ethnobotanical parameters. Results: There are 77 strict endemic species, as well as 209 species shared with one or two neighbor states. The first belong to 30 families and 61 genera. The mountain ranges of Surutato, Concordia, and Tacuichamona have the most strictly endemic plants. More than half of the species are only known from the type locality and six of them have not been collected in more than 100 years. Lopezia conjugens and Croton ortegae were rediscovered after more than 100 and 70 years, respectively. Ebenopsis caesalpinioides, Stenocereus martinezii, and Aloysia nahuire were the priority species due to their high biocultural value. Conclusions: The endemic plants from Sinaloa show high taxonomic diversity and cultural value. This work identified species and sites of conservation priority, as well as the needs for collection and the potential of extinct species.

Although Tansley originally proposed the ecosystem concept in 1935, ecosystem science underwent significant development in the last 20 years, as in this period it has been consolidated with concepts and methods arisen in convergent disciplines, such as ecosystem genetics, ecological stoichiometry, global ecology, and ecosystem services. The objective of this paper is to review new concepts and methods of water, energy, and nutrient dynamics research in terrestrial ecosystems to contribute to generate a new theoretical framework in the field of ecosystem science. From this review, a new conceptual definition of ecosystem is required based on three key issues: (a) the integration of functional processes at different spatial and temporal scales to understand the ecosystem dynamics in its environmental context; (b) the concept of resource (i.e., water or nutrients) use efficiency as a key metric for ecosystem function; and (c) the role of biological species in ecosystem functioning, using the genetic framework. These new concepts and methods are necessary to advance in the research on ecosystem functioning and resilience in the context of the current environmental crisis that includes processes such as ecosystem degradation, biodiversity loss, and global climate change. Finally, this new conceptual definition must be linked to evolutionary theory and global ecology research.

Background: Carbon (C) stocks in the world's forests amount to 861 Pg; 44 % is in the soil. Despite its importance as a reservoir, studies on soil organic carbon (SOC) in forests of Mexico are scarce. Questions: Does soil organic carbon vary between vegetation types and soil types in Durango forests? Study site: Temperate forests of Durango, Mexico. Methods: SOC data were obtained from 399 permanent sites. Samples were collected from leaf litter, fermentation horizon and from the 0-30 and 30-60 cm soil layers. C contents were determined on an elemental analyzer. Uncertainties were calculated following the procedures used by the National Forestry Commission. Results: The average SOC was 8.48, 1.08, 110.62 and 53.44 Mg ha-1 in litter, fermentation horizon, 0-30 and 30-60 cm soil, respectively. The average total soil C stocks ranged from 26.34 to 578.27 Mg ha-1 (uncertainty: 6.31 %). The greatest variability of SOC stocks occurred in pine forest. Conclusions: Forest type does not influence soil organic carbon pools, but soil type does. SOC pools in Durango forests are higher compared to the same type of vegetation in other regions of the country.

Background: As part of the taxonomic revision of the genus Clethra in Central America, two new species from Honduras were discovered. The two new species described here have been confused mainly with C. lanata, C. mexicana and C. salvadorensis. Question: Are foliar trichomes useful to distinguish species? Taxon: Species of Clethra. Study site: Central and southern mountain ranges of Honduras. Methods: Relevant literature on Clethra was reviewed and specimens from six herbaria were examined. Type material from all morphologically similar species, as well as those taxa with which the two new species have previously been confused were compared. Results: Clethra albertinae and C. standleyana are described and illustrated as new and endemic species from Honduras, both belong to ser. Tomentosae. Clethra albertinae is most closely related to C. licanioides, a species endemic to Guatemala, and C. standleyana is most closely related to C. nicaraguensis, a widespread species that occurs from Mexico (Chiapas) to Nicaragua. Based on the IUCN Red List a conservation assessment of Vulnerable and Endangered is recommended for both new species. An updated list and key to the nine species of Clethra for the flora of Honduras is proposed. Conclusions: The foliar trichomes turned out to be diagnostic and in combination with characters of the inflorescences can used to separate of all Honduran species of Clethra. In Central America, Honduras is the third country with most species rich of this genus after Guatemala and Costa Rica.

Background: Different regionalizations have been proposed for the Sierra Madre Oriental (SMOR), but none of them have analyzed its full floristic diversity. Hypothesis: The geographical distribution of the vascular plant species of the SMOR allows the identification of floristic regions with unique species that identify them as biogeographic units. Studied species: Vascular plants. Study site: Sierra Madre Oriental physiographic province, Mexico. Methods: Plant species distribution was analyzed in 1 × 1° latitude and longitude grid cells. Characteristic species (those with half or more of their known geographical distribution in Mexico in the SMOR) were identified, and a classification method was applied to distinguish biogeographic regions. Results: 8,472 species were recorded in the Sierra Madre Oriental, 3,433 of them considered characteristics, of which 2,158 are endemic to Mexico and 585 are considered strictly endemic to the province. The portions of the SMOR in the states of Coahuila, Nuevo León, Tamaulipas, and San Luis Potosí have a higher species richness and this richness decreases towards the south of the province. Five floristic districts were identified within the SMOR. Conclusions: The phytogeographic analysis carried out and its comparison with other regionalizations shows there is still disagreement in the biogeographic delimitation of the Sierra Madre Oriental and to achieve this goal it is necessary to include neighboring provinces in the analyzes, which will allow to identify their unique species and define their biogeographic limits in a more precise way.

Biodiversity in ecosystems is crucial in providing ecosystem services and their stability and resilience. However, most studies supporting the benefits of biodiversity in crop health were studied at the cultivar scale, generally without specifying the resistance mechanisms involved in the resistance of crops to pests. Thus, it is unclear if phytochemical diversity is one of those resistance mechanisms and whether the ecosystem patterns and processes in which phytochemical diversity is involved can be replicated or adapted to the management of sustainable agroecosystems. Here, I review the roles of phytochemical diversity in natural ecosystems and determine if they can be helpful in the management of agroecosystems. I briefly review (a) the spatial and temporal structure of phytochemical diversity in ecosystems and its effect on plant consumers; (b) how that diversity is generated and maintained; and (c) the current or potential role of phytochemical diversity in agroecosystems. The α-, β-, and γ-phytochemical diversities are very high in ecosystems and landscapes; phytochemical diversity gets displayed in dynamic mosaics of mixtures of secondary metabolites that vary in their concentration and composition within and among individuals, populations, or species. Phytochemical diversity is fostered by evolutionary or coevolutionary processes, mainly under an arms-race scenario. The patterns and processes of phytochemical diversity are idiosyncratic depending on the identity of the interacting species and the local biotic and abiotic environment; thus, to copy them to industrial agroecosystems is hardly viable. However, five recommendations in which phytochemical diversity could be helpful in agroecosystem management are made.

Background: High post-dispersal fruit-seed removal can be a bottleneck for successful propagation to new areas of plant populations with fragmented distribution, as in cloud forest. Therefore, it is important to know how vegetation and fruit-eating behavior will influence the spatial removal pattern. Questions and/or Hypotheses: How do vegetation structure and density influence fruit removal of Persea hintonii in potential propagation areas? Study site and dates: Las Joyas Scientific Station, Sierra de Manantlán Biosphere Reserve, Jalisco, Mexico. April-May 2015. Methods: The number of fruits removed were recorded in treatments excluding of different size vertebrates, in areas with a dense or sparse understory within two forest types plus open areas with shrub cover. To identify vertebrate fruit-removing species, camera-traps were placed under the canopy of P. hintonii trees with high fructification amounts. Results: Fruit removal was lower in areas of low understory density at pine-oak forests (11.17 ± 5.30 %) and gap areas (25.5 ± 2.39 %), compared to subtropical cloud forests (72.51 ± 0.60 %). The number of days to start the fruit removal was lower in the cloud and pine-oak forests with dense understory than in those with a sparse understory. We identified six mammal and three bird species as removers of P. hintonii fruits, among which Pecari tajacu and small mammals were the most important fruit removers. Conclusions: Low density understory in pine-oak favor less fruit removal of P. hintonii, probably associated with the behavior of its consumers.