Tropical Wooded Peatland in Delta Amacuro State, Venezuela

Abstract

Reconnaissance on edaphological and biological aspects was carried out in a peatland forest near the town of Piacoa in Delta Amacuro State, southeastern Venezuela. Thirteen peat samples were taken in a stratigraphic transect, using Ramsar peat extraction and analysis protocol to study tropical peatlands. Physicochemical parameters were characterized with basic laboratory analysis: color according to the Munsell scale, relative humidity, solubility in water, specific density, pH, conductivity, percentage of organic carbon and percentage of organic matter. Rapid ecological evaluation of vegetation and ichthyofauna associated with aquatic bodies was carried out. Part of a large extension of Orinoco peatlands in delta region, the study area is a marshy wetland which, according to the Ramsar classification, qualifies as forested peatlands (Xp category). Paleoclimatic, palynological and edaphological information in the literature indicates that the peatlands were formed during Holocene processes of marine transgression that occupied settling basins and lowlands where the vegetation was not very different from the current one. Samples collected at different depths (0 to 220cm) clearly show horizons with two color tones: one dark or black (associated with a good surface aeration), and a yellowish brown or brown, associated with an absence or little amount of oxygen as it goes deeper. The pH values decrease with depth (4.25 at the top and 3.9 or 3.5 at depth). The peat has a high water retention that ranges between 60% and 83%. Vegetation in the wetland is diverse: 31 species of plants within 14 families that include tree, shrub and hydrophilic grassland vegetation were identified. In associated water bodies, 41 species of fish grouped within 27 families were found