The main objective of this study is to determine the effects of land-use change on useful plant species diversity in lowland rainforest and three regionally important agricultural systems: jungle rubber agroforests, rubber plantations, and oil palm plantations. Large numbers of indigenous people are still living in the vicinity of forest. Wild plant species support their livelihood through their various uses such as medicine, poisons, dyes, shelter, fibre, for religious and cultural ceremonies. Further, forest foods such as wild fruits, nuts, vegetables etc. have an important role in contributing for food security, to fulfil household nutrition during the time of lean seasons or in the period of little agricultural productions. We would like to learn more about the distribution of useful plant species and individuals in the different land-use systems, differences in use categories, and the relation of useful plant species to general plant species richness.
We expect that the variety of useful plants is higher in species rich systems such as rainforests. As the agricultural systems are, however, planted with useful plants, it is possible that they surpass forests in term of individual numbers of useful plants. In this context, we will investigate species and individual richness of useful plants and their use categories across four land-use systems. Hereby we address the following research questions: (1) how are useful plant species and individuals distributed along an intensification gradient? (2) Which use categories can be found in which land-use system? (3) How is the relationship between useful plant diversity and general plant diversity?