STATUS AND TRENDS IN MANGROVE AREA EXTENT WORLDWIDE (original) (raw)
Venezuela
Vegetation description
Mangrove forests are found in the Orinoco delta and along the banks of Lake Maracaibo. The Orinoco delta encompasses a vast branching system of channels around the estuary of the river and holds the largest stands of mangroves in Venezuela. In the North it adjoins the tropical rainforest. In the south there is a fairly low swamp forest. Mangrove forests spread a long way inland (40 km) along the banks of waterways and are made up mainly of Rhizophora mangle, Laguncularia racemosa, Avicennia tomentosa, A. officinalis and Conocarpus erectus. Where they are less exposed to the tides, they are mixed with Pterocarpus officinalis, Bravaisia integerrima and Clusia sp. There is no shrub or grass layer.
FAO, UNEP. 1981. Los Recursos Forestales de la America Tropical. Proyecto de Evaluaci�n de los Recursos Forestales Tropicales (en el marco de SINUVIMA). FAO, UNEP, Rome, 349 pp.
National level mangrove area estimates
| Year | Area (ha) | Source | Trend | Methodology/Comments |
|---|---|---|---|---|
| 1961 | 810 000 | MAC. 1961. Atlas forestal de Venezuela | Cited in: FAO, UNEP. 1981. Los Recursos Forestales de la America Tropical. Proyecto de Evaluaci�n de los Recursos Forestales Tropicales (en el marco de SINUVIMA). FAO, UNEP, Rome, 349 pp. It represents the extent of the entire wetlands, but the percentage of mangroves is not reported. | |
| 1975 | 323 237 | Carrero O. et al. 1982. Mapa de la vegetaci�n actual de Venezuela. Ministerio del Ambiente y de los Recursos Naturales Renovables. Documento de trabajo. VEN/79/001. | Remote sensing. Scale 1:250 000. The "Year" is the average year of the images. | |
| 1980 | 260 000 | Unesco/C.I.T.V. 1981. Vegetation Map of South America (Scale 1:5 000 000) | X | Cited in: FAO, UNEP. 1981. Los Recursos Forestales de la America Tropical. Proyecto de Evaluaci�n de los Recursos Forestales Tropicales (en el marco de SINUVIMA). FAO, UNEP, Rome, 349 pp. |
| 1982 | 630 200 | Spalding, M.D., Blasco, F. and Field, C.D., eds. 1997. World Mangrove Atlas. The International Society for Mangrove Ecosystems, Okinawa, Japan. 178 pp. | Map analysis. Scale 1:2 000 000. | |
| 1983 | 673 600 | Saenger, P., Hegerl E.J. and J.D.S., Davie. 1983. Global status of mangrove ecosystems. Commission on Ecology Papers No.3. IUCN. Gland, Switzerland. 88 pp. | Secondary reference, no primary source provided. The "Year" is the publication year. | |
| 1986 | 250 000 | MARN. 1986. Conservaci�n y Manejo de los Manglares Costeros en Venezuela y Trinidad & Tobago. (Sintesis) (PT) Serie Informes T�cnicos DG11A/IT/259 Caracas | X | Cited in: Conde, J.E. and Alarc�n, C. 1993. Mangroves of Venezuela. Lacerda, L.D. 1993. Conservation and sustainable utilization of mangrove forests in Latin America and Africa regions. Vol. 2 Part I- Latin America. p. 211-244. Mangrove Ecosystems technical reports ITTO/ISME Project PD114/90 (F). Okinawa, Japan. 272 pp. |
Trends in mangrove area extent over time
EXPLANATORY NOTES
Most recent, reliable estimates
The figure chosen as the most recent, reliable estimate is underlined in the table with national level estimates. In the charts it is shown in bold.
Formulas used for the trend analysis
Exponential: y = cebx where c and b are constants, and e is the base of the natural logarithm
Linear: y = mx + b where m is the slope and b is the intercept.
Logarthmic: y=c ln x + b where c and b are constants, and ln is the natural logarithm function.
Power: y=cxb where c and b are constants.
Polynomial trendline: y=b+c1x+c2x2+c3x3+..+cnxn where b and _c1�cn_are constants.
BIBLIOGRAPHY
FAO. 1995. Forest Resources assessment 1990: Global synthesis. FAO Forestry Paper No. 124. Rome, 46 pp.
FAO. 2001. _Global Forest Resources Assessment 2000: main report._FAO Forestry Paper No. 140. Rome, 479 pp. www.fao.org/forestry/fo/fra/main/index.jsp
