Aproximación geográfica de las condiciones de amenaza sobre la vegetación: zonificación multicriterio de tres áreas en declaratoria de protección, localizadas en la Orinoquía colombiana

Abstract

Se presenta una zonificación de las amenazas a la vegetación en las áreas en proceso de declaratoria de protección en la Orinoquia colombiana (alto Manacacías, sabanas y humedales de Arauca y Selvas transicionales de Cumaribo). Se evidenciaron conflictos entre la conservación y las actividades antrópicas, a nivel local por demanda de bienes y servicios ambientales, originados por los medios de subsistencia, y a nivel regional por construcción de vías y actividades extractivas, debido a la demanda global de metales e hidrocarburos. La distribución geográfica de las unidades jerarquizadas de la vegetación, definidas por técnicas fitosociológicas, se fundamentó en clasificaciones alternadas y complementarias de imágenes satelitales. Esta novedosa aplicación metodológica demostró amplias ventajas frente a las aproximaciones europeas, que se basan únicamente en criterios fisionómicos. Como modelo multicriterio de zonificación, se utilizó un Proceso de Análisis Jerárquico; se integraron 14 criterios de uso del suelo, actividades extractivas, poblamiento humano y vías de acceso. La articulación del modelo de zonificación a un Sistema de Información Geográfica permitió identificar los tipos de vegetación con mayor amenaza y evidenció ventajas frente a las metodologías usuales de zonificación, fundamentadas en procesos de superposición espacial, al establecer e integrar estimaciones de prioridades entre criterios jerarquizados. El trabajo es una contribución metodológica multivariada a la Geografía, fundamentada en técnicas novedosas que integran variables biofísicas y socioeconómicas, las cuales intervienen en la funcionalidad territorial.

Abstract: A zoning of threats to vegetati on is presented on areas in proc ess of declaration of protection located in the Colombian Ori noquia. Several social and economic aspects of the areas of influence proposed by Nat ional Natural Parks were integrated Th ese territories are characterized by low populati on density, undeveloped infrastruc ture and basic road conditions, equipment and basic sanitation. T he human populations in areas of interest present a young structure, high birth and inci pient economic and human developm ent; the population ́s structure and dynamics have been influenced mainly by violence and econom ic activities developed in their territories, corresponding to coca crops in the transitio nal forests of Cumaribo and the exploration and exploitation of hydrocarbons in the alto Manaca cías and the savannahs and wetlands of Arauca. The main produ ctive activities are farming and indigenous occupations, these livelihoods of s ubsistence exert strong pressure on the v egetation of the region, which induces deforestation and burning for the establishment of past ures for extensive cattle and illicit crops. The spatial dist ribution of vegetation of the th ree areas in declaration of protection responds differentially to water and topographic gradients defi ned by the geomorphological elements. In alto Manacacías the large formation of Axonopus purpusii and Paspalum pectinatum predominates with more than hal f of the area considered and el even differentiated vegetable coverages, presents the physiognomies of grasslands a nd scrublands that grow mainly on terraces and hills of the well-drained Orinoquia. In the Savannahs and Wetlands of Arauca the large formation of Axonopus purpusii and A. anceps predominates with about half the area under consideration and f our different vegetation cove rings, includes physiognomies of grasslands and scrublands on po or drainage lands in the basi n of the badly drained Orinoquia. In the transitional f orests of Cumaribo predominates the large formation of Minquartia guianensis and Phenakospermum guyannense with about three quarters of the proposed area and four land coverings of upland and evergreen f orests, located on alluvial terraces with different degrees of dissection. The wooded and l ow vegetation coverings with greater threat were identified in the areas in the process of p rotection, corresponding to, respectively, the Mauritia flexuosa and Hieronyma alchorneoides communities and the grass- scrubland of Andropogon bicornis and Lippia alba in the territory of alto Manacacías, the degraded forests of Connarus venezuelanus and Zanthoxylum fagara , the grass-scrubland of Axonopus purpusii and Eriosema simplicifolium and the grass-scrubland of Axonopus purpusii and Eriosema simplicifolium in the area of the Savannahs and Wetlands of Arauca, and the forests of Doliocarpus dentatus and Leptobalanus apetalus and the shrubby and flooded low forests of Scleria gaertneri and Symmeria paniculata located in the transitional forests of Cumaribo