Native forest tree conservation in tropical agroforests: Case study of cacao farms in the Atlantic Forest of southern Bahia, Brazil

摘要

Agroforests are model systems for ecological conservation in tropical agricultural landscapes because they integrate biodiversity conservation and rural livelihoods. Whether agroforests are long-term solutions for conserving biodiversity in agricultural landscapes may depend sapling regeneration of native forest trees in agroforests. In this dissertation, I ask two main questions: are native forest trees regenerating in agroforests and if so, what are the ecological and social drivers? I tested the influence of potential seed sources from both the landscape and parent trees found in the agroforest. I also examined how a set of social factors affected native forest tree regeneration. The social drivers I tested include tree management and use, land tenure and state-restricted rights to harvest native timber. I found that a number of native pioneer species are regenerating at relatively high frequencies and abundances. I also found that many secondary native forest tree species are also regenerating although their sapling are found less frequently and at lower abundances. Most primary forest tree species present as adults are not regenerating and lacked sapling in the agroforests. The influence of the ecological factors was limited. The main drivers of native forest tree regeneration on farms are the understorey management and the rural extension services that assisted farms obtain state-restricted rights.