EXPANSION WITHOUT EXTINCTION: HOW CAN BIODIVERSITY BE PRESERVED IN IRRIGATION SYSTEMS
The state of biodiversity of the area under ongoing irrigation development was quantified for the first time, and included new distribution records and socially and economically important species for people. For example, more than 223 species of flowering plants belonging to 56 families were identified from the major vegetation/habitat types defined for the study area and 295 vertebrate species from 100 families, including 10 endemics and 31 nationally threatened species. Positive and negative trends in the total landscape area comprising dominant habitats and in abundances of select taxonomic groups were documented with increasing irrigation development including, for example, progressive losses in the total area under natural vegetation and increases in areas under wetland habitat or human infrastructure, increases in the distribution and area occupied by invasive alien plants, increases in the abundance of primarily aquatic taxa such as some amphibian species and water-dependent birds, and losses in forest bird richness.
The socio-economic conditions and diverse livelihoods systems of people living in different irrigation development contexts, and issues of local concern, were ascertained and quantified as far as possible. For example, while higher income levels and literacy rates were reported from sample locations already under irrigation and the new scheme is providing infrastructure to improve conditions for people in undeveloped areas, a number of problems pertaining to growing pressures on land, water and other natural resources are emerging with the increasing population in the developing areas that cannot be addressed by irrigation infrastructure development alone (e.g. allotment of livestock grazing lands; access to water supply). More diverse livelihoods systems were apparent in undeveloped areas, where there was a greater reliance on non-timber forest products and other natural resources, many of which were highly valued by the community. With irrigation development certain trends emerged, such as a decline in Chena farming with scrub jungle clearing, increases in wage work where people’s agricultural activities were temporarily disturbed, an increase in human-elephant conflicts, etc. Several ecoagriculture strategies were identified, some of which were implemented during the course of the project (e.g. biodiversity refuges, Biodiversity Park, indigenous species in road reservations and fuel wood plantations), while a biodiversity action Programme with short and longer-term activities was developed with local stakeholders for agreed implementation under the Mahaweli Authority’s ongoing Integrated Development Programme for the area.