Environmental History of Mangrove Vegetation in Pacific West-Central Mexico during the Last 1300 Years

AbstractMangroves are a highly threatened ecosystem due to climate change and human activity, which increases coastal vulnerability. Knowledge about the ecological dynamics of mangroves on a centennial timescale can reveal the different responses in vegetation, which is useful for implementing basic actions for mangrove restoration, conservation and management. A mangrove ecosystem in the Cuyutlán Lagoon area along the Pacific coast of west-central Mexico is significantly altered as a result of industrialization, salt extraction, and road construction. The long-term dynamics of the mangrove ecosystem has also been controlled by Holocene climatic variability. This study reconstructs the environmental history of mangrove vegetation around the Cuyutlán Lagoon during the last ~1300 years in response to periods of human activity and climate change. The reconstruction was performed using paleoecological techniques in sediment cores that include the use of fossil pollen as a proxy for vegetation and magnetic susceptibility and geochemical data (determined by loss-on-ignition and X-ray fluorescence) as a proxy for past environmental changes. The chronology was determined using 14C dating and the age-depth model was constructed by linear interpolation. Redundancy analysis and non-metric multidimensional scaling (NMDS) were used to discern patterns of distribution of the different proxies. Results revealed that the mangrove pollen assemblage of the Cuyutlán Lagoon was dominated by the arboreal taxa Rhizophora mangle, Euphorbiaceae, Moraceae and Pinaceae, herbaceous taxa like Poaceae, Chenopodiaceae/Amaranthaceae, and aquatics such as Typhaceae and Cyperaceae. NMDS showed a clear separation between two events of human activity—the Spanish Occupation of Colima (~AD 1523-1524) and the opening of the Manzanillo port (~AD 1824-1825). Climate change events such as the Medieval Climate Anomaly (MCA) (~AD 800-1200) and the Little Ice Age (LIA) (~AD 1350-1850) were also successfully identified. The main responses were mangrove expansion (driven by R. mangle) during the LIA and the Manzanillo Port Opening, while the MCA was a highly perturbed period marked by multiple hurricane events and low or no pollen deposition in the sediment. During the Spanish Occupation, the aquatic taxa Typhaceae expanded together with an increase in Ca, Sr and carbonate contents

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

Cloud forest dynamics in the Mexican neotropics during the last 1300 years

Key questions for understanding the resilience and variability of Mexican Neotropical cloud forest assemblages in current and future climate change include: How have human disturbances and climate change affected the dynamics of the cloud forest assemblage? What are the predominant processes responsible for its present day composition and distribution? Are the current conservation strategies for the cloud forest in accordance with preserving its natural variability through time? In this study, the temporal dynamics of the cloud forest in west-central Mexico over the last ~ 1300 years were reconstructed using paeleoecological techniques. These included analyses of fossil pollen, microfossil charcoal, and sediment geochemistry. Results indicated that a cloud forest assemblage has been the predominant vegetation type in this region over the last ~ 1300 years. During this time, however, there have been changes in the vegetation with an apparent expansion of cloud forest from ~ 832 to 620 cal years BP and a decline from 1200 to 832 cal years BP. Climate change (intervals of aridity) and human disturbances through anthropogenic burning appear to have been the main factors influencing the dynamics of this cloud forest. The spatial heterogeneity reported for high-altitude forests in this region, in concert with high beta diversity, appears to be a manifestation of the high temporal variability in species composition for these forests. Greater turnover in cloud forest taxa occurred during intervals of increased humidity and is probably representative of a higher temporal competition for these resources among the cloud forest taxa. The present results support the current protection scheme for cloud forests in west-central Mexico where areas are kept in exclusion zones to avoid timber extraction, grazing, and agriculture; this will maintain diversity within these forests, even if there are only a few individuals per species, and enable the forests to retain some resilience to current and future climate change

Opinión y perspectiva de los productores de caña de azúcar del valle Grullo-Autlán, Jalisco, en relación a los apoyos de las organizaciones cañeras locales

Las actividades campesinas en el valle de El Grullo-Autlán son de gran importancia para el progreso y tranquilidad social de sus habitantes, ya que los cultivos básicos son parte importante en su economía y consumo. En las últimas décadas la caña de azúcar ha jugado un papel relevante en el desarrollo de esta región dada la gran importancia de este cultivo tanto a nivel nacional, como internacional y donde la demanda del mismo es parte sustancial en la economía mundial. Esta actividad ha permitido detectar bajo la percepción de algunos actores (ejidatarios, ingenio, asociaciones e inclusive gobierno), situaciones que generan molestia en los mismos,  malos entendidos en el accionar de la cadena productiva de la caña de azúcar reflejados principalmente en los costos de los insumos del cultivo. Uno de los propósitos de este estudio es dar a conocer el sentir y perspectiva  de los productores de caña de azúcar en relación a las organizaciones cañeras locales (CNPR y CNC).  Los resultados muestran como la mayoría de los productores de caña de azúcar confían en las organizaciones cañeras locales ya que reciben los apoyos técnicos y económicos de manera ágil y expedita, aun así una pequeña minoría muestra su inconformidad en cuanto a los apoyos económicos y lenta asesoría técnica, aunado a los cada vez más altos costos de los fertilizantes

Dynamics and silviculture of montane mixed oak forests in Western Mexico

The full-text of this book chapter is not available in ORA, but the original publication is available at springerlink.com (which you may be able to access via the publisher copy link on this record page). Citation: Olvera-Vargas, M. et al. (2006). Dynamics and silviculture of montane mixed oak forests in Western Mexico. In: Kappelle, M. (ed.) Ecology and conservation of neotropical montane oak forests. Berlin, Springer, pp. 363-374

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