INVESTIGADORES
PRADO Darien Eros
artículos
Título:
Neotropical seasonally dry forests and Quaternary vegetation changes
Autor/es:
PENNINGTON, R.T.; D.E. PRADO; C.A. PENDRY
Revista:
JOURNAL OF BIOGEOGRAPHY
Editorial:
Blackwell Publishing
Referencias:
Lugar: Hoboken, New Jersey; Año: 2000 vol. 27 p. 261 - 273
ISSN:
0305-0270
Resumen:
Seasonally dry tropical forests have been largely ignored in discussions of vegetation
changes during the Quaternary.
We distinguish dry forests, which are essentially tree-dominated ecosystems, from open
savannas that have a xeromorphic fire-tolerant, grass layer and grow on dystrophic, acid
soils. Seasonally dry tropical forests grow on fertile soils, usually have a closed canopy,
have woody floras dominated by the Leguminosae and Bignoniaceae and a sparse
ground flora with few grasses. They occur in disjunct areas throughout the Neotropics.
The Chaco forests of central South America experience regular annual frosts, and are
considered a subtropical extension of temperate vegetation formations.
At least 104 plant species from a wide range of families are each found in two or more
of the isolated areas of seasonally dry tropical forest scattered across the Neotropics, and
these repeated patterns of distribution suggest a more widespread expanse of this vegetation,
presumably in drier and cooler periods of the Pleistocene.
We propose a new vegetation model for some areas of the Ice-Age Amazon: a type of
seasonally dry tropical forest, with rain forest and montane taxa largely confined to gallery
forest. This model is consistent with the distributions of contemporary seasonally dry
tropical forest species in Amazonia and existing palynological data.
The hypothesis of vicariance of a wider historical area of seasonally dry tropical forests
could be tested using a cladistic biogeographic approach focusing on plant genera that
have species showing high levels of endemicity in the different areas of these forests.