Presencia de seudobroquita en unos suelos y roca madre de la Isla Ferrera (Columbretes)

En el estudio general que se está realizando de las islas Columbretes con motivo de la expedición llevada a cabo en mayo de 1964, en la que tomaron parte investigadores especializados en distintas ramas de las ciencias de la naturaleza, nos ha correspondido a nosotros realizar nuestro trabajo, dentro del estudio mineralógico de los suelos.Al margen del estudio sistemático de la mineralogía de los suelos de los islotes de Ferrera, Columbrete Grande y el peñón de Mancolibre y de sus rocas de origen, damos cuenta en esta nota, de la presencia de seudobroquita en los suelos de isla Ferrera, encontrándose en sus fracciones arena (0,2-0,02 mm), esta especie mineral que no aparece en los suelos de las otras islas

Carbon dioxide emissions of Antarctic tourism

The increase of tourism to the Antarctic continent may entail not only local but also global environmental impacts. These latter impacts, which are mainly caused by transport, have been generally ignored. As a result, there is a lack of data on the global impacts of Antarctic tourism in terms of energy consumption and carbon dioxide emissions. This paper presents and applies a methodology for quantifying CO2 emissions, both for the Antarctic vessel fleet as a whole and per passenger (both per trip and per day). The results indicate that the average tourist trip to Antarctica results in 5.44 t of CO2 emissions per passenger, or 0.49 t per passenger and day. Approximately 70% of these emissions are attributable to cruising and 30% to flying, which highlights the global environmental relevance of local transport for this type of touris

Life-history traits in an evergreen Mediterranean oak respond differentially to previous experimental environments

Living organisms respond both to current and previous environments, which can have important consequences on population dynamics. However, there is little experimental evidence based on long-term field studies of the effects of previous environments on the performance of individuals. We tested the hypothesis that trees that establish under different environmental conditions perform differently under similar post-establishment conditions. We used the slow-growing, evergreen Mediterranean oak <i>Quercus ilex</i> subsp. <i>rotundifolia</i> as target species. We analyzed the effects of previous environments, competition effects and tradeoffs among life-history traits (survival, growth, and reproduction). We enhanced seedling establishment for three years by reducing abiotic environmental harshness by means of summer irrigation and artificial shading in 12 experimental plots, while four plots remained as controls. Then these treatments were interrupted for ten years. Seedlings under ameliorated environmental conditions survived and grew faster during early establishment. During the post-management period, previous treatments 1) did not have any effect on survival, 2) experienced a slower above-ground growth, 3) decreased root biomass as indicated from reflectivity of Ground Penetration Radar, 4) increased acorn production mostly through a greater canopy volume and 5) increased acorn production effort. The trees exhibited a combination of effects related to acclimation for coping with abiotic stress and effects of intra-specific competition. In accordance with our hypothesis, tree performance overall depended on previous environmental conditions, and the response was different for different life-history traits. We recommend early management because it increased plot cover, shortened the time to attain sexual maturity and increased the amount of acorn production. Plots such as those assessed in this study may act as sources of propagules in deforested agricultural landscapes thus aiding natural establishment of new plants

Geographic patterns of vertebrate diversity and identification of relevant areas for conservation in Europe

The ‘EU Council conclusions on biodiversity post–2010′ re–enforced Europe’s commitment to halt biodiversity loss by 2020. Identifying areas of high–value for biodiversity conservation is an important issue to meet this target. We investigated the geographic pattern of terrestrial vertebrate diversity status in Europe by assessing the species richness, rarity, vulnerability (according to IUCN criteria), and a combined index of the three former for the amphibians, reptiles, bird and mammals of this region. We also correlated the value of all indices with climate and human influence variables. Overall, clear geographic gradients of species diversity were found. The combined biodiversity index indicated that high–value biodiversity areas were mostly located in the Mediterranean basin and the highest vulnerability was found in the Iberian peninsula for most taxa. Across all indexes, the proportion of variance explained by climate and human influence factors was moderate to low. The results obtained in this study have the potential to provide valuable support for nature conservation policies in Europe and, consequently, might contribute to mitigate biodiversity decline in this region

Factors influencing vegetation cover change in Mediterranean Central Chile (1975-2008)

Las figuras y apéndices que contiene el documento se localizan al final del mismo.Questions: Which are the factors that influence forest and shrubland loss and regeneration and their underlying drivers?\ud \ud Location: Central Chile, a world biodiversity hotspot.\ud \ud Methods: Using land-cover data from the years 1975, 1985, 1999 and 2008, we fitted classification trees and multiple logistic regression models to account for the relationship between different trajectories of vegetation change and a range of biophysical and socio-economic factors.\ud \ud Results: The variables that most consistently showed significant effects on vegetation change across all time-intervals were slope and distance to primary roads. We found that forest and shrubland loss on one side and regeneration on the other often displayed opposite patterns in relation to the different explanatory variables. Deforestation was positively related to distance to primary roads and to distance within forest edges and was favoured by a low insolation and a low slope. In turn, forest regeneration was negatively related to the distance to primary roads and positively to the distance to the nearest forest patch, insolation and slope. Shrubland loss was positively influenced by slope and distance to cities and primary roads and negatively influenced by distance to rivers. Conversely, shrubland regeneration was negatively related to slope, distance to cities and distance to primary roads and positively related to distance from existing forest patches and distance to rivers.\ud \ud Conclusions: This article reveals how biophysical and socioeconomic factors influence vegetation cover change and the underlying social, political and economical drivers. This assessment provides a basis for management decisions, considering the crucial role of perennial vegetation cover for sustaining biodiversity and ecosystem services.This work was financed by the REFORLAN Project, INCO Contract CT2006-032132 (European Commission), with additional input from projects CGL2010-18312 (Spanish Ministry of Science and Innovation) and S2009AMB-1783 (Madrid Government REMEDINAL-2). We are in-\ud debted to Javier Salas and Cristian Echeverría for their input in this project. The manuscript benefited from\ud useful comments from Jorge Aubad and two anonymous\ud reviewers, who improved the contents and presentation\ud of this stud

Aspectos micromorfológicos de solos de uma topossequência ocorrendo em zona tropical húmida (Superficie da Quibala - Angola)

info:eu-repo/semantics/publishedVersio

The differential influences of human-induced disturbances on tree regeneration community: a landscape approach

Understanding the processes shaping biological communities under interacting disturbances is\ud a core challenge in ecology. Although the impacts of human-induced disturbances on forest ecosystems have\ud been extensively studied, less attention has been paid to understanding how tree regeneration at the\ud community level responds to such disturbances. Moreover, these previous studies have not considered how\ud these effects change according to major social and environmental factors that can influence forest use at a\ud landscape scale. In this study, we investigate the effects of cattle grazing and selective logging on the\ud composition of tree regeneration communities in relation to forest successional stage and land tenure regime\ud in Chilean temperate forests, a global biodiversity hotspot. We recorded seedlings, saplings and basal area of\ud stumps of tree species (as a surrogate for selective logging), and number of cattle dung pats (as a surrogate\ud for cattle pressure) in 129 25 3 20 m plots in small (,200 ha) and large properties in different successional\ud stages (old-growth, intermediate, secondary forests). The regeneration of the ten more abundant species as\ud predicted by human disturbance, land tenure, forest successional stage, and number of parent trees was\ud modelled using generalised linear models. Predictions for each individual model were made under different\ud scenarios of human disturbance. The predicted regeneration results were assembled and subjected to\ud ordination analyses and permutation multivariate analyses of variance to determine differences in\ud regeneration composition under each scenario. In most cases, best-fit models contained at least one of the\ud explanatory variables accounting for human disturbance. The effects of selective logging on tree regeneration\ud varied depending on land tenure regime, but cattle grazing always exhibited a negative effect. Our results\ud revealed that cattle have a more negative effect on forest regeneration than selective logging, especially in\ud old-growth forests and small properties. Our analytical approach contributes to the understanding of the\ud differential influence of human-induced disturbances on the tree regeneration community at a landscape\ud scale. It can inform conservation policies and actions, which should focus on addressing themain disturbance\ud factors and on developing strategies to conserve the most sensitive species to such disturbances.C. Zamorano-Elgueta was supported by a CON-\ud ICYT pre-doctoral fellowship (Government of Chile),\ud the European Comission (Project contract DCI-ENV/\ud 2010/222-412), the Chilean NGO Forest Engineers for\ud Native Forest (Forestales por el Bosque Nativo, www.\ud bosquenativo.cl) and project REMEDINAL-2 (Comu-\ud nidad de Madrid, S2009/AMB-1783). L. Cayuela was\ud supported by project REMEDINAL-2. This work is\ud part of the objectives of projects CGL2010-18312\ud (CICYT, Ministerio de Economı́a y Competividad de\ud Espana). The authors acknowledge the valuable\ud support of Vero ́nica Pı́riz, Cony Becerra, Rodrigo\ud Gangas, Oscar Concha, Eduardo Neira and staff from\ud the Valdivian Coastal Reserve, as well as the National\ud Forest Service of Chile (Corporación Nacional Forestal