205

24% of the identified wetland areas in the national territory are being used by anthropogenic activities that cause partial changes in their ecology.

such as flood regulation, pollutant filtration, provision of water and food, and cultural and spiritual services1-4. Colombia, wetlands are considered strategic ecosystems because they guarantee and maintain the equilibrium of basic ecological processes5. This characteristic has made them centers of human settlement; subsequently, accelerated changes have altered wetland land covers and more than half of the wetlands in the world have been lost in the last century6.

In Colombia, 24% of the areas identified as wetlands, which are found in the map of Colombian wetlands7, have been affected by changes caused by human activity. These transformations, reflected in land cover changes, evidence alterations in the ecosystems, as is supported by the analysis of satellite images. Currently, the greatest fraction of wetland areas is being used mainly for cattle raising or agriculture, or the areas have been deforested by an expanding agricultural frontier. To a lower degree, mining, urbanization, the construction of civil works, soil degradation, and forest fires are human activities that also appear in wetland areas. This study reveals that cattle raising is the main activity present in Colombian wetlands. In the country, cattle raising uses four million hectares of these areas, coinciding with the drivers of change that affect wetlands in other parts of the world8-10.

Most of temporary and medium and low potential wetlands are being intervened7. This suggests that the strong seasonality of these types of wetlands, in which a layer of water may be absent during a certain period of time, may explain why productive activities are more frequent in these places; there is a lack of knowledge regarding their ecosystemic importance and relevance when managing flooding risks.

The identification of anthropic land covers in wetland areas gives an initial alert of the magnitude of transformation in the country. However, these results must be complemented by an analysis of how each anthropogenic use may affect the integrity of wetlands, and to what degree. Such study is hindered by the peculiarities of each driver of change in the affected areas. For example, there has been no evaluation of the impacts or the loading capacities of raising buffalo livestock in Colombia, so it is still unknown if wetlands may support this kind of use without affecting ecosystemic integrity. In contrast, transhumant cattle raising, traditionally employed in the Orinoquia and the basin of Magdalena-Cauca, has been compatible with natural dynamics of floods and droughts for decades. As a result, wetland management should consider different policies with specific designs for each area because land cover use in the country is varied.

In this context, comprehensive assessments of the natural dynamics of these ecosystems are evermore important in order to determine which are the consequences and long-term effects of inducing change in wetland areas on the services they provide.