Analysis of the vegetation-soil-water interaction and external factors on the water availability in a rain forest
Ramos J.1*, Gracia J.1, Ortiz S.1, González-Chávez, J. L.2, Iturbe R.1, Rodríguez-Martínez T.1
1 Instituto de Ingeniería, UNAM 2 Facultad de Química, UNAM
*jramosh@iingen.unam.mx
In general, degradation of water quality due to human and natural (less common) causes leads to the loss of the environmental value of the ecosystem which is vital to the survival of its habitats. Different forms of nature degradation (biological, physical and chemical among others), particularly those linked to humans, could reduce the capacity of the system to get a gradual recovering or adaptation (resilience). Sometimes, many of the changes that occur are not detected on time or these increase quickly imposing pressure in the system unable to recover by itself, thus human intervention is required in order to return the ecosystem to its own value. In the case of water, availability depends on several factors in order to cover water demands to maintain or restore the benefits that humans receive, and to define hydrological aspects that define the ecosystems. The above involves both ecological interactions as well as external factors such as the presence of humans, changes in seasonal patterns of flow, physicochemical characteristics of water bodies, and the type and amount of pollutants entering these water bodies. Thus, the aim of this paper is to establish how the changes of land use have a major impact affecting water quality and therefore availability considering also soil type and vegetation. For this, nine aguadas (a type of cenotes) were monitored at the Natural Protected area Calakmul Biosphere Reserve, whose importance is based on sustaining the ecosystem for different species, as well as being used as a source of supply water for animals and humans. Particularly, the paper assesses the effect on the quality of the aguadas with and without direct human impact. Results show that deforestation around bodies of water, transforming jungle into agricultural area, has been crucial since it creates a climatic transition zone affecting the water characteristics and conditions. Direct effects such as the erosion which drags nutrients and soil materials into the water bodies are also considered. Additionally, the presence of microorganisms (total coliforms) due to the combined use in situ of water for human and animal was observed. The natural influence by rock washing or erosion in the subsurface and surface has an effect on production systems due to the presence of carbonates, sodium, calcium, magnesium and potassium by the type of soil. Also, strontium levels (<0.5 mg/l) were found at a concentration related to natural soil sources in the zone. Although, human activities are pressing the ecosystem, its resilience capability helps to recover the resource maintaining some water quality for drinking and direct use. However, if the tendency of destruction continue, short-term water goals and targets will not be sufficient for the conservation and sustainable use of biodiversity and ecosystems. Thus, in order to regulate human relationship with nature activities, it is necessary to predict the consequences of changes in drivers for biodiversity, ecosystem functions, and ecosystem services, together with the improved measures of biodiversity, thus these will help to maintain a sustainable system looking at the long term and at different scales.