Cambodia is a small country in the continental South-east Asia adjacent to the Gulf of Thailand. It has an area of 181,035 km2 between 10 and 15o N and 102 and 108oE. The country possesses 2,308 plant species belonging to 852 genera in 164 families including 7 genera and 14 species belonging to Gymnosperms; 219 genera and 488 species belonging to Monocotyledons; and 626 genera and 1,806 species belonging to Dicotyledons. As no systematic and complete study has been done, it is estimated that a full list for Cambodia is expected to exceed 3,000 species, with expectations that at least 700 additional species will be described as new to science in the country (Aswell, 1997). The World Conservation Monitoring Centre 2000 estimates 8,260 plant species in Cambodia, 10% of which will be endemic.
57 and 125 taxa of aquatic macro invertebrate were recorded in a few surveys in two provinces in 1991 and 2001 respectively including Insecta, Oligochaeta, Mollusca, Crustacea and others. 28 species of amphibian and reptile are described. A total of 874 fish species are recorded, of which 490 - freshwater fishes from 64 families, 410 - saltwater fishes from 83 families, 22 are threatened; 1 endemic; 13 introduced fish species. Over 500 birds have been recorded but it is likely that the number goes easily to over 600.
Cambodia protected areas system include 7 national parks (742,250 ha), 10 wildlife sanctuaries (2,030,000 ha), 3 protected landscape (9,700 ha), 3 multiple use areas (403,950 ha), 6 protection forests (1.350,000 ha), and 8 fish sanctuaries (23,544 ha).
Cambodia's forests have decreased significantly in terms of both area and quality over the last few decades. As of late as 1969, the country's forests covered around 13.2 million hectares, or 73% of the country's total land area. However, a recent forest resource assessment by FAO (2005) indicates Cambodia to have lost more than a quarter of its remaining primary forest since 2000, and ranks the country third in the world for primary forest loss. Regardless of the differences, trend in forest changes accelerated during the period from 1997 and 2002 by approximately 5% or 1% per year (IFSR 2004) and still increased further between 2002 and 2005 at a rate of 2% (CDRI 2006) and afterward.
Of 490 freshwater fish species, at least 45 species are already to be commercially important and 22 threatened fish species are recognised for their conservation significance. There is increasing prominent that the aquatic habitat is being converted for agriculture, other land use types, and the fish migration pattern is constrained by hydrological infrastructure development, particularly in the upstream of the Mekong and irrigation scheme locally in the flood plain. The flooded forest extended over more than 1 million hectares originally, had reduced to only 614,000 hectares in the 1960s and 362,000 hectares in 1991.
Recent surveys by the International Rice Research Institute (IRRI) have identified over 2000 different strains of rice used in Cambodia. Of the total rice cropping area 2,585,905 ha (2007) in Cambodia, 86% is rainfed lowland rice, 8% is Dry season rice, 4% is floating rice and 2% is upland rice.
A number of categories of threats to the country biodiversity are listed. Genetic erosion is due to the fact that people were unable to preserve the old varieties that they used to possess earlier, changes in agricultural system, increasing use of agricultural chemicals, pesticides, and herbicides are potential cause for loss of genetic resources and the introduction of new farming systems. Habitat loss is due to demand for increased agricultural lands, fuelwood and non-timber forest products and infrastructure development. Unsustainable harvesting includes hunting, logging, burning, non-timber forest product (NTFP) collection and over-fishing. Hydropower development and urban and industrial development are putting pressure on the aquatic ecosystems through changes in hydrological regime and pollution. The presence of alien species, some of them were for farming purposes, is becoming a threat that would potentially enhanced under climate change situation.