
The Amazon is the greatest river system on the planet. Twenty per cent of the world’s freshwater enters the oceans through the river basin. It’s an immense amount of water, but the flow isn’t constant. The Amazon regularly bursts its banks with the seasons and the consequences are massive. River banks that were land can be submerged below ten metres of water and in this landscape that means flooding penetrates deep into the forest. Indeed, the wetlands of the Amazon form the largest floodplain in the world. They cover 300,000km2 – an area ten times the size of Belgium.
Ferreira et al. report on how the huge differences in water levels pose a selective pressure on plants in this extremely diverse and intensely competitive ecosystem. They look at the VΓ‘rzea (archive), the white-water floodplains and the IgapΓ³, black-water floodplains with a lower pH. The pressures of adapting to life in such a changeable environment can be seen in the variety of sexual and asexual reproduction methods used by plants. Responses to the extremes of flood and drought have been under-studied. FerreiraΒ et al. document some of the strategies used in an ecosystem that will produce new challenges in the future.
This is an open-access publication and can be read without charge at AoB Plants.
I’ve always been fascinated by this ecosystem, although more specifically the fauna that inhabit it rather then the flora.
I was looking at the downloads of papers from Annals of Botany in the last year. In the top ten of most downloaded paper was one from 1997 (almost before downloads were invented!), which featured this ecosystem of the Brazilian cerrado vegetation – 10.1006/anbo.1997.0469 A paper long before its time, and hardly cited, but now the threats to the diversity of this ecosystem are becoming recognized widely and people have recognized the issue.
The Brazilian Cerrado Vegetation and Threats to its Biodiversity
J. A. RATTER, J. F. RIBEIROΒ and S. BRIDGEWATER Annals of Botany 80: 223±230, 1997
also located at http://ecologia.ib.usp.br/ecovegetal/
Brazil’s cerrado wins protection, but will it be enough to save the wildlife-rich grassland?
mongabay.com
September 15, 2010
Brazil announced a plan to protect the cerrado, the vast woody savanna that covers 20 percent of the country but has become the nation’s biggest single source of carbon emissions due to conversion for agriculture and cattle pasture, reports Brazil’s Ministry of the Environment.
Unveiled today in Brasilia, the $200 million initiative establishes the “political framework for the conservation and sustainable use of the most threatened biome in Brazil,” according to a statement released by the ministry …
http://news.mongabay.com/2010/0915-cerrado_consservation.html