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H. Arellano-P.

Publications and source records attributed to H. Arellano-P..

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CCA Fuzzy Land Cover: a new method for classifying vegetation types and coverages and its implications for deforestation analysis

Land cover has been evaluated and classified on the basis of general features using reflectance or digital levels of photographic or satellite data. One of the most common methodologies based on CORINE land cover (Coordination of Information on the Environment) data, which classifies natural cover according to a small number of categories. This method produces generalizations about the inventoried areas, resulting in the loss of important floristic and structural information about vegetation types present (such as palm groves, tall dense mangroves, and dense forests). This classification forfeits relevant information on sites with high heterogeneity and diversity. Especially in the tropics, simplification of coverage types reaches its maximum level with the use of deforestation analysis, particularly when it is reduced to the two classes of forests and nonforests. As this paper demonstrates, these results have considerable consequences for political efforts to conserve the biodiversity of megadiverse countries. We designed a new methodological approach that incorporates biological distinctiveness combined with phytosociological classification of vegetation and its relation to physical features. This approach is based on parameters obtained through canonical correspondence analysis on a fuzzy logic model, which are used to construct multiple coverage maps. This tool is useful for monitoring and analyzing vegetation dynamics, since it maintains the typological integrity of a cartographic series. The methodology creates cartographic series congruent in time and scale, can be applied to multiple and varied satellite inputs, and always evaluates the same model parameters. We tested this new method in the southwestern Colombian Caribbean region and compared our results with those from what we believe are outdated tools used in other analyses of deforestation around the world.

q-bio.QM

A solution for reducing high bias in estimates of stored carbon in tropical forests (aboveground biomass)

A nondestructive method for estimating the amount of carbon stored by individuals, communities, vegetation types, and coverages, as well as their volume and aboveground biomass, is presented. This methodology is based on information on carbon stocks obtained through three-dimensional analysis of tree architecture and artificial neural networks. This technique accurately incorporates the diversity of plant forms measured in plots, transects, and relevés. Stored carbon in any vegetation type is usually calculated as half the biomass of sampled individuals, estimated with allometric formulas. The most complete of these formulas incorporate diameter, height, and specific gravity of wood but do not consider the variation in carbon stored in different organs or different species, nor do they include information on the wide array of architectures present in different plant communities. To develop these allometric models, many individuals of different species must be sacrificed to identify and validate samples and to minimize error. It is common to find cutting-edge studies that encourage logging to improve estimates of carbon. In our approach we replace this destructive methodology with a new technique for quantifying global aboveground carbon. We demonstrate that carbon content in forest aboveground biomass in the pantropics could rise to 723.97 Pg C. This study shows that a reevaluation of climatic and ecological models is needed to move toward a better understanding of the adverse effects of climate change, deforestation, and degradation of tropical vegetation.

q-bio.QM