Simplification of forest fragments: a fact to be considered

Human activities have, over the centuries, modified, destroyed and impoverished the planet's existing biomes. Recent evidence shows that most existing plant species are declining as a result of these activities. Scientific studies demonstrate that a large part of the endemic and native species of some regions are being replaced by a much smaller number of other species, and that these develop better in environments modified by human actions.

This type of activity destroys, over the years, important biomes such as the Atlantic Forest and the Cerrado in Brazil, for example, which have enormous biodiversity, with a large number of endemic species of both fauna and flora and which, according to Myers et al. (2000), it is considered one of the world's “hotspots” with priority areas for conservation, that is, with high biodiversity, and threatened to the highest degree.

Some authors warn and define this type of replacement and reduction of diversity in forest fragments as a process of biological simplification or homogenization. Tabarelli et al. (2009) observe that in forest fragments, the simplification of environments in tree communities can reduce species richness, increasing the number of pioneer trees and reducing trees from ecological groups typical of undisturbed forests (secondary and climax). In this context, forest remnants become increasingly similar in species composition and ecological groups.

A very striking fact accompanying this process is that the majority of forest fragments, especially those surrounded by an anthropic matrix, have been suffering from geographic isolation and the reduction of their areas. In addition to these factors, the remnants are affected by other disturbances that can interact with the process of biological fragmentation and simplification. Forest fragments are usually degraded by fires, cutting down trees and hunting and these changes drastically alter their ecology, further increasing the process of homogenization in their composition and structure (LAURANCE and COCHRANE, 2001).

It is obvious that more studies need to be carried out on the effects of the fragmentation process and the biological dynamics of these remnants. One of the main points would be to determine which factors are linked to the fact that forest fragments resemble areas in an initial or intermediate stage of regeneration.

Understanding the process of biological simplification or homogenization will be a challenge, because there is still a lack of research that deals with the different, quite complex, aspects of the decline in biodiversity, such as the extinction and introduction of invasive species. Solutions to contain this process must be developed and discussed, in addition to being placed as a priority in order to conserve and recover the biodiversity that we still have.

Biologist, Master and PhD student in Forestry Sciences

Forest Engineer, Master's student in Forest Engineering