Congresspersons in Brazil have been lobbied by “ruralists” (farmers strongly interested in agribusiness), to perform amendments to our “Código Florestal Brasileiro” (Brazil’s Forest Code) aiming to reduce the extension of natural areas protected by our present environmental legislation, with respect to rivers and stream margins, top of hills and mountains, and their slopes. The amendment to the code would also change the current requirement that Amazonian landowners must retain 80% of their land as legal forest reserves. The amendment would also provide amnesty to any farmers or ranchers who have practised illegal deforestation by incorporating over 40 million hectares of illegally deforested land.
Especially with respect to riparian vegetation we presently know that any terrestrial ecosystem fragment is affected by external factors, like high temperature and sun radiation, blasts of wind and lower air and soil humidity. This is what we call
edge effects. Experiments in tropics revealed that such effects extend for about 100m inside the forest fragment. Therefore, it is not difficult to conclude how big the negative effects would be to fragments with much less than 100m wide! The politicians who support the amendments to Brazil’s Forest Code (YES! the same politicians who approved the increase of their own salary in 61.8%!!!) stipulate that riparian vegetation of small rivers and streams should be reduced from the current 15m (in 10m wide rivers) to 5m. Yet, vegetation of hills and mountains tops and of their slopes may be exploited. Farmers might use these fragile habitats for cultivation. Such modification of law that protects such fragile environments are being planned by the lobbists even after the 2008 environmental disaster which occurred in Rio de Janeiro, the ones that happened in the Northeastern states of Pernambuco and Alagoas in June/2010, and the present tragedy that has destroyed everything downhill, again in Rio de Janeiro. This time the tragedy in Rio inflicted almost 600 casualties to local population (it can be more in the next days!). Natural disaster? Fierce storm of Nature? May be. But with quite strong anthropic collaboration.
Let us observe how important it is to estimate the external effects on a forest fragment, be it a square or rectangular fragment. A square fragment 2km at each one of its side makes up a 4km2 area (four square kilometers); and a rectangular fragment measuring 1km at one side by 4km at the other side totals also four square kilometers. However, the perimeters of these forms of fragment are different: the four sides of the square area sums up
8km; and the four sides of the rectangular area sums up
10km. So the rectangular fragment would be more affected by the edge effect. This latter area is similar to riparian edges of rivers and streams. Suffice it to say how bad will be the consequences to riparian areas if their plants cover is reduced! The rivers sedimentation (= bed agradation) will certainly be increased and floods will certainly happen quite frequently, and catastrophically as it happened in Pernambuco and Alagoas recently.
Local authorities, in my point of view, are the most important actors of such tragedies. Main reasons: 1) They are responsible for allowing people to build their houses in slopes of hills, down in the valleys, close to rivers margins… and practically at any place poor people intend to dwell. 2) They are also responsible for not providing environmental education to people who are used to throw their wastes in the rivers from which they obtain their drinking water! 3) Deforestation (logging, slash-and-burn cultivation…) are practised under slackness and complacency of authorities.
I still have to emphasize some important ecological factors affected by reduction of vegetation cover proposed in the amendment. Some few examples: 1) In the state of São Paulo, 45 of the 66 fish species of fresh waters and threatened to extinction live in streams (according to biologist Lilian Casati of "Universidade Estadual de São Paulo". 2)Reptiles and amphibians living in wetlands will also be impacted by the reduction of riparian vegetation; and according to biologist Luis Felipe of the "UNICAMP-Universidade de Campinas" places with the least protection (proposed by the amendment to Brazil's Forest Code) are the ones with highest biodiversity!!! 3) Mountains (their tops and slopes)are important shelters for reptiles (in the amendment natural habitats above 1800m altitude will no more be permanently protected areas).
The leader congressman responsible for the amendments to Brazil’s Forest Code, Mr Aldo Rebello, says that many Brazilian researchers were consulted to elaborate the amendments. But oddly his experts’ advice differs strongly of experts’ investigations who has published on environmental degradation which resulted from reduction of riparian vegetation in our ecosystems (see METZGER et al., Science, vol. 329, 10/July/2010; and in Portuguese see site http://eco.ib.usp.br/lepac/codigo_florestal.html, and in this site download the essay: Sparovek_etal_2010.pdf).
Mr Rebello, the federal deputy who claims that “it is necessary to conquer those new environments to expand our agriculture” is strongly opposed by the general chief of environmental research (Celso Manzatto) at EMBRAPA – The Brazilian Agricultural Research Corporation, who says: “We showed in the last 20 years that we are able to gain in productivity without the need to incorporate new lands. This does not mean that we are going to have zero deforestation! What we need but we do not have done it yet, is a policy to organize our territory pointing out which areas must be occupied for production of animal husbandry in the future”.
The need of amendment to Brazil’s Forest Code is also opposed by Gerd Sparovek (in the essay mentioned above), who says that we must expand our agriculture to areas where we have been practising extensive cattle farming with very low productivity (1.1 animal per hectare) [the average productivity in Southeastern Brazil is 4.5 animals per hectare]. Gerd Sparovek estimates that
circa 61 million hectares are in such conditions, among the 211 million hectares exploited in cattle farming.
Unfortunately, not only politicians but many key actors in our society do not realize that “
a long time has elapsed from the stage we had to conquer by slash-and-burn forests to the present stage of commitment to preservation and restoration”.
