An alternative approach to biodiversity evaluation: case study in the Lower Mekong Basin
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Biodiversity has played an important role in human society, not only through direct economic benefits but also through indirect non-economic benefits. As biodiversity changes so humans need to reconsider its value. Biodiversity evaluation is poorly quantified because it is highly complex at different levels - genetic, species and ecosystem - and based on multidimensional concepts. It is difficult to incorporate biodiversity value into an impact assessment (IA) even though it is a desirable process, which helps to ensure that the project / programme / policy / development avoids damaging the environmental, social and economic sectors.This study aims to explore constructive biodiversity evaluation with regard to 1) specieslevel as species composition, species richness and species diversity; 2) ecosystem level as carbon storage and other services; and 3) human level as socio-economic aspects. These indicators are normally identified as non-monetary values or are sometimes valued from an economic point of view through contingent valuation or shadow pricing. Specifically, this study attempts to quantify the value of biodiversity indicators within the ecosystem structure and function. Species and habitat diversity can represent a component of ecosystem structure and, at the ecosystem level can also represent ecosystem functions (goods and services). Carbon storage in ecosystems becomes a legitimate representation of ecosystem services related to C02 mitigation, and global climate change objectives. Moreover, humans are considered as a component in biodiversity to take account of socio-economic aspects. These biodiversity indicators must be weighed equallyTo assess wider biodiversity evaluation and a new alternative IA approach, these developments have been tested in a case study of the planned Ban Koum Hydropower Project in the Lower Mekong Basin. An analysis of species composition, richness and diversity showed that main effects of dam construction would be a quantifiable loss of the riparian zone and destruction of its plant associations. Construction also causes major loss of species diversity in phytoplankton and change in dominance. It is estimated that 0.66x106 tonne of stored carbon will be lost from terrestrial ecosystem through inundation but a further 3.60xl06 tonne will be lost as the loss of carbon storage potential and the result of human encroachment into primary forest over a period of 50 years. This compares to a gain of 0.56xl06 tonne if there is no dam construction. Depending on mitigation options, the economic value of carbon loss is $47-851 million and the carbon gain without construction would be $13-244 million. A questionnaire survey of local families before and after dam construction showed a decline in quality of life, economic security and job opportunity from the dam development project.This revised IA approach can lead to improved assessment of proposed developments through more reliable techniques that focus on consideration of carbon storage at the global scale, species diversity at the regional scale and socio-economics at the local scale. This revised IA can also improve the decision-making process by providing a more holistic and realistic approach to natural resource use.