Included here is the lowland region known as llanos extending through northern Colombia and western Venezuela. It also extends along the coastal zone of Venezuela from the Paraguana Peninsula west to the start of the Amacuro Delta and incorporates the middle reaches of the Orinoco River.

Llanos Wet Savanna

With these savannas periodic inundation is frequent during the wet season often to a depth of up to 0.3 m and they may remain flooded for several months at a time. Two wet savanna types have been recognized on the Colombian Llanos. These include Mesosetum Savanna and Andropogon Savanna. The first is largely confined to the aeolian plain, which although flooded during the wet season, the water table can drop to a subsurface depth of up to 2 m in the dry season. Here the dominant grasses are Mesosetum chaseae, M. rottboellioides and Eriochloa holcoides, while other common grasses are Andropogon virgatus, Axonopus anceps, Leptocoryphium lanatum and Trachypogon ligularis. Sedges like Rhychospora barbata and R. globosa are also common together with the shrubs Buettneria jaculifolia and Jassiaea lithospermifolia. This formation has much in common with wet savanna found the Llanos of central Venezuela. In places where the depth of floodwater increases other species may become conspicuous such as the shrub Rhynchanthera grandiflora, the tree Caraipa llanorum or the palm Maurita minor. Andropogon Savanna occurs mainly in the low basins of alluvial overflow plains on heavy clay soil with poor drainage where even during the dry season the water table is close to the surface. The vegetation has a fairly complex structure and often includes several layers. The dominant grasses are Andropogon bicornis, A. hypogynus, A. virgatus and Sorghastrum parviflorum. Common upper layer species include Axonopus anceps and the shrubs Buettnera jaculifolia and Jussiaea lithospermifolia. At medium heights the grasses Eriochrysis holcoides and Setaria geniculata are usually conspicuous together with the sedges Cyperus haspan and Rhyncospora barbata. At the lowest level Panicum laxum, P. parviflorum and Paratheria prostrata are common.

References

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