Secondary Succession under invasive species (Pteridium aquilinum) conditions in a seasonal dry tropical forest in southeastern Mexico

The role of invasive species in ecosystem functioning represents one of the main challenges in ecology. Pteridium aquilinum is a successful cosmopolitan invasive species with negative effects on the ecological mechanisms that allow secondary succession. In this study, we evaluated the influence of P. aquilinumon secondary succession under different disturbances in a seasonal dry forest of the Yucatán Peninsula. We determined species richness, composition and the relative importance value in four sampling units. Fabaceae followed by Asteraceae, Meliaceae, Rubiaceae, Sapindaceae and Verbenaceae were the most species rich families. A dissimilarity analysis determined significant differences in beta diversity between sampling units. With a generalized linear model we found that species richness was best explained by site conditions, followed by calcium and soil organic matter. Also, the generalized linear model showed that abundance resulted in a strong correlation with site conditions and soil characteristics. Specific soil conditions related to phosphoro and calcium were also detected as beneficiary to the successional processes. Our results suggest that applying fire restriction and periodic cutting of the bracken fern, this can increase a higher diversity of species

La Red Internacional de Inventarios Forestales (BIOTREE-NET) en Mesoamérica: avances, retos y perspectivas futuras

Conservation efforts in Neotropical regions are often hindered by lack of data, since for many species there is a vacuum of information, and many species have not even been described yet. The International Network of Forest Inventory Plots (BIOTREE-NET) gathers and facilitates access to tree data from forest inventory plots in Mesoamerica, while encouraging data exchange between researchers, managers and conservationists. The information is organised and standardised into a single database that includes spatially explicit data. This article describes the scope and objectives of the network, its progress, and the challenges and future perspectives. The database includes above 50000 tree records of over 5000 species from more than 2000 plots distributed from southern Mexico through to Panama. Information is heterogeneous, both in nature and shape, as well as in the geographical coverage of inventory plots. The database has a relational structure, with 12 inter-connected tables that include information about plots, species names, dbh, and functional attributes of trees. A new system that corrects typographical errors and achieves taxonomic and nomenclatural standardization was developed using The Plant List (http://theplantlist.org/) as reference. Species distribution models have been computed for around 1700 species using different methods, and they will be publicly accessible through the web site in the future (http://portal.biotreenet.com). Although BIOTREE-NET has contributed to the development of improved species distribution models, its main potential lies, in our opinion, in studies at the community level. Finally, we emphasise the need to expand the network and encourage researchers willing to share data and to join the network and contribute to the generation of further knowledge about forest biodiversity in Neotropical regions

Succession and the Relationship between Vegetation and Soil in the Marl Quarries of the Yucatan Peninsula, Mexico

Open-pit mining is a common activity in the Yucatan Peninsula for the extraction of limestone. These areas are characterized by the total removal of the natural vegetation cover and soil in order to access calcareous material. The present study shows the composition and structure of the vegetation in five quarries after approximately ten years of abandonment, and the target vegetation near to the quarries in southeastern Mexico. A linear mixed model showed that P availability is one of the limiting factors for species establishment in the quarries. Using a canonical correspondence analysis (CCA), the distribution of the species was determined in relation to the edaphic variables: soil depth, the percentage of organic matter (OM), cationic exchange capacity (CEC), pH and texture. Twenty-six families, 46 genera and 50 species were recorded in the quarries, and 25 families, 45 genera and 47 species were recorded in the conserved areas. The dominant species in the quarries belong to the families Poaceae, Fabaceae, Rubiaceae and Anacardiaceae. The quarries with higher values of OM (2%), CEC (24 Cmol/kg), depth (11 cm) and sand percentage (31%) include the following species Lysiloma latisiliquum (L.) Benth., Metopium brownei (Jacq.) Urb. and Bursera simaruba (L.) Sarg., which are common in secondary forests. Quarries with lower values of OM (0.4%), CEC (17 Cmol/kg) and depth (5.02), and with a higher percentage of silt (42%) were dominated by herbs belonging to Poaceae and by Borreria verticillate (L.) G. Mey., which are typical in disturbed areas of southeastern Mexico. In all cases, the pH was slightly alkaline due to the content of calcium carbonate (CaCO3), characteristic of the soils of the region

Plant/soil-microbial fuel cell operation effects in the biological activity of bioelectrochemical systems

Plant and soil microbial fuel cells (PMFCs and SMFCs, respectively) are bioelectrochemical systems that produce energy using microorganisms as catalysts. This energy can be harvested; however, its impact on biological activity has seldom been explored. To reveal the main characteristics of this impact, we monitored four experimental designs for 20 days under open-sky conditions. The effect of PMFC/SMFC start-up on metabolism was evaluated by photosynthesis of Codiaeum variegatum and heterotrophic soil respiration to determine the short-term effects. To compare the results, a normalized parameter of power density, which considered the PMFC/SMFC configurations, solar irradiance, and soil temperature, was introduced. The highest energy was obtained for the PMFC configuration. The energy harvesting stimulated the photosynthetic rate of C. variegatum up to two times with respect to its normal values, while the heterotrophic soil respiration decreased 30%. Thus, in the PMFC and SMFC start-up operations, the increase in soil temperature due to energy harvesting suggests that soil temperature is the most relevant parameter influencing plant metabolism and energy generation. These results open a new pathway for understanding the bioregulation of plants/soil when subjected to energy harvesting.Fil: Valdez Hernández, Mirna. El Colegio de la Frontera Sur; MéxicoFil: Acquaroli, Leandro Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Vázquez Castillo, Javier. Universidad de Quintana Roo; MéxicoFil: Gonzalez Perez, Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Electroquímica Aplicada e Ingeniería Electroquímica; ArgentinaFil: Heredia Lozano, Julio C.. Universidad de Quintana Roo; MéxicoFil: Castillo Atoche, Alejandro. Universidad Autónoma de Yucatán; MéxicoFil: Sosa Vargas, Lydia. Université Pierre et Marie Curie; FranciaFil: Osorio de la Rosa, Edith. Universidad de Quintana Roo; Méxic

Projected conservation status of forest species in Central America and southern Mexico under four different climate change scenarios by the year 2070.

We classified species in our dataset (n = 1924) into IUCN Red List categories following the A3 criterion [58]. Different colors represent the percentage of species in each category, which are further separated into two alternative RCPs (top semicircles, RCP4.5; bottom, RCP8.5) and two dispersal assumptions: outer circle (A), limited dispersal; inner circle (B), unlimited dispersal. The complete species dataset is presented in S4 Table).</p

Pearson correlation analysis of 18 variables obtained from Worldclim 1.4 [48] for 10,000 randomly chosen points across the study area.

Cells above the diagonal show the r value; cells below the diagonal show the density distribution. (PDF)</p

Model averaged coefficients of the effect of change in climate variables on the proportion of threatened species under the RCP8.5 and limited dispersal scenario.

Coefficients were estimated using only those models where the variable was included.</p

Name, number of occurrences, and parameters used to evaluate the species distribution model of 1924 plant species evaluated in this study.

Name, number of occurrences, and parameters used to evaluate the species distribution model of 1924 plant species evaluated in this study.</p