Terra Firme

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Typical of the terra firme forests are the overhangers : individual trees that clearly tower above the canopy of the forest

Terra firme ( Portuguese and Spanish solid land ) is a local name in South America for the ecosystem of the tropical lowland rainforest (especially in the Amazon basin ) outside the floodplains of the rivers.

It is differentiated from the rainforest ecosystems in the regular flood area: Forests in the flood area of ​​sediment-rich white water rivers are called Várzea , those in the flood area of ​​humic acid- rich black water rivers are called Igapó . These flooded forests , although they also belong to the most species-rich forest types on earth, do not achieve the biodiversity of the terra-firme forests.

characterization

The typical terra-firme forest is located in the Amazon basin in a more or less level position at sea levels of less than 100 meters. Roughly speaking, it takes up about half of the total area of ​​the rainforest. In its physiognomy and appearance it resembles tropical rainforests elsewhere, also on other continents. It is typical that most of the biomass is fixed in the vegetation itself, while the soil, mostly a lateritic ferralsol , is very poor in humus and biomass and hardly stores any plant nutrients. The crown space is typically multilayered. Even on the mostly poor soils it is very rich in tree species; For example, in an investigation of three areas of one hectare each in Central Amazonia, the following were counted: 285 species from 47 families, 280 species from 48 families and 280 species from 44 families.

In the western Amazon basin, the following sub-types were distinguished, which also occur in a similar form in the other parts:

  • Terra-firme low terraces: most common type, on level terraces away from rivers, on loamy soils. The crown layer height is at least 20 meters, individual protrusions up to 45 meters, the aboveground biomass supply between 400 and 560 tons per hectare .
  • Terra-firme subsidiary races: This type of forest is directly adjacent to deeply cut watercourses (locally called barrancos ), but is not or only rarely flooded.
  • Palm swamps (locally bosques de quebrada ). These are located in the marshy lowlands of the terra firme ; they do not get their water from flooding the rivers, but from rainwater. They are typically poor in tree species. Palms like the Buriti palm (or morichal ) Mauritia flexuosa can build dominant populations . The crown layer reaches a height of about 12 to 30 meters.
  • Terra-firme forests on white sand ( Caatinga , other names Campina Amazônica, Campinarana or Pseudocaatinga): Forests on extremely nutrient-poor quartz podsol . Better varianes ( varillal ) are still fairly closed forests with a crown layer height of between 10 and 20 meters, but shrub-like formations ( chamizal ) that are barely 3 meters higher with interspersed single trees up to 8 meters in height and open, heather-like areas ( bana ) .

Due to the high dynamics of the rivers in the Amazon basin, supported by the low relief, the rivers shift their course quite regularly. This can lead to the fact that forests, which are now typical terra firme , were also floodplain forests in historical times; this must be taken into account when analyzing the species composition.

swell

  • Jörg Pfadenhauer & Frank Klötzli: Vegetation of the Earth: Basics, Ecology, Distribution . Cape. 2.1: Tropical lowland rainforests . Springer-Verlag, 2015. ISBN 978-3-642-41950-8

Individual evidence

  1. ↑ Florian Wittmann, Jochen Schöngart, Wolfgang J. Junk: Phytogeography, Species Diversity, Community Structure and Dynamics of Central Amazonian Floodplain Forests. Chapter 4 in WJ Junk et al. (editors): Amazonian Floodplain Forests: Ecophysiology, Biodiversity and Sustainable Management. Ecological Studies 210. Springer Verlag, 2010 doi : 10.1007 / 978-90-481-8725-6_4
  2. ↑ Alexandre A. De Oliveira & Scott A. Mori (1999): A central Amazonian terra firme forest. I. High tree species richness on poor soils. Biodiversity and Conservation 8: 1219-1244.
  3. ↑ Randall W. Myster (2009): Plant Communities of Western Amazonia. Botanical Review 75 (3): 271-291. online access via JSTOR
  4. ↑ Randall W. Myster (2014): Varzea forest vs. terra firme forest floristics and physical structure in the Ecuadorean Amazon. Ecotropica 20: 35-44.

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