A Multi-Scale Ecological Approach for the Conservation and Restoration of Venezuelan Andean Cloud Forests
摘要
The Andean eco-region of South America is one of the most prominent biodiversity hotspots in the world, which can be attributed to the multiplicity of heterogeneous environments largely driven by a complex of latitudinal and altitudinal gradients. An important feature of this landscape is the presence of the diverse and structurally complex Andean cloud forests (ACFs), which are fundamental in the provision of ecosystem services, mainly linked to water provision and regulation and protection against erosion, ability to absorb and store a substantial amount of carbon in the form of soil organic matter (SOM) and plant biomass, and high levels of biodiversity and endemism. In this chapter, we focus on the Venezuelan Andes to review an important body of work on how these ecosystems function and their current conservation state. We also explore how this accumulated knowledge can provide guidelines for conservation, restoration and adaptation planning. We reviewed ecological studies conducted at different spatial scales, from the landscape to plant levels, to describe the main structural and functional characteristics of the Andean cloud forests in Venezuela. Andean cloud forests in Venezuela are well represented in the protected area system of the country, mainly National Parks. Despite deforestation rates being relatively stable and low (0.1% per year) in recent years, a great proportion of this area is distributed within a mosaic of small fragments (often <10 ha) with strong edge effects from the surrounding grassland matrix. In general, the small forest patches tend to be dominated by species described as early successional colonizers of gaps. Studies of ecosystem processes have shown that replacing forests with pastures limits the ability to regulate water flows, diminishing fog catchment, soil water storage and deep drainage. Long-term forest dynamics studies show how elevation and low temperatures are key drivers of a “slow dynamics” and therefore relatively low turnover rates, also implying a slow rate of recovery from disturbances. Recent investigations on shade tolerance of cloud forest tree species and their associated ecophysiological properties, showed a great potential for the planning of restoration practices based on a functional approach.