The importance of biodiversity

• Autor(a) principal: Santos, Fernando Santiago
• Data de Publicação: 2010
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Paidéi@
• Texto Completo: https://periodicos.unimesvirtual.com.br/index.php/paideia/article/view/167
• topic: Biologia; biodiversidade; interferência antrópica; taxas de extinção de espécies.

Various definitions of the term biodiversity can be pointed out: some are very simple (richness of species number), whereas others are more complex (variety of living beings on Earth as a result of billions of years of evolution, which is shaped with natural selection processes and also because of human activity interference). Biodiversity may also be interpreted by considering the intra-specific variation and might include, in a larger view, the variety of types of communities or ecosystems within a certain region. There is still little consensus amongst researchers about the number of species that inhabit our planet. The broad range of estimates (from three to 30 million species) can be asserted, from a set of several causes, due to difficulties to identify and describe biological groups and to list and report species that are actually being extinct. Some recent numbers place Brazil as one of the so-called mega-diverse countries, with about 50,000 phanerogamic species and with 13% of the world total number of plants, animals and fungi. Moreover, few Brazilian States have vegetal and animal checklists. Complete works on fauna and flora are reported for the States of Sao Paulo and Santa Catarina; in Sao Paulo, for instance, the program Biota (Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP) has catalogued about 2,000 new species throughout tem years of research activities. To preserve the genetic heritage on Earth, twenty five areas with high endemism rates and anthropogenic pressure (hot spots) have been recognized: 44% of plant species of the world and 35% of vertebrate species (excluding fishes) are found in such areas. The Atlantic biome and the Brazilian savanna (Cerrado stricto sensu) are two national hot spots that are highlighted within the world scenario. The “Sistema Nacional de Unidades de Conservação” (National System of Conservation Units - SNUC), with the aim to preserve and conserve the national biological heritage, recognizes various Conservation Units, such as the Whole Protection Units (National Parks and Biological Reserves, for example), and the Sustainable Use Units (National Forests, Natural Heritage Private Reserves and so forth). Countless are the threats to biodiversity, mainly throughout the inter-tropical regions (which have been favored, in millions of years, with hot and icy periods that shaped both the climate and the structure of the planet): habitat destruction, introduction of exotic species via ballast water, seed traffic etc., endemism rate shrinking, animal and plant smuggling, predatory hunting and fishing, species extinction and so forth. In such contexts, it is mandatory to investigate the role of key-species within ecosystemic ecological functions and the degree of damage caused with key-species extinction, as well as the susceptibility to diseases and mass killing that may be observed amongst populations whose individuals share little genetic variation. Checklists carried out by experts of the UN Convention on Biological Diversity highlight species disappearance rates that sometimes are 100 times higher than those of the natural extinction. Such rates have recently grown exponentially. By considering this, it is very important and urgent that both the governments and the organized society make decisions to target viable alternative solutions so that development and growth might be achieved without endangering the huge biological richness of our biosphere.