Seed harvesting of a threatened African tree dispersed by rodents: Is enrichment planting a solution?

Abstract

Non-timber forest products (NTFPs) provide income to local communities with less ecological harm than timber extraction. Yet overharvesting can still influence the regeneration and sustainability of these resources. Developing sustainable harvesting practices for emerging NTFPs depends on the biology of the NTFP species, the ecological context in which management occurs, and its cost in terms of effort and resources. Allanblackia stuhlmannii (Clusiaceae) is a canopy tree species whose seeds are a source of vegetable oil and an important food for rodents. In an experiment within the Amani Nature Reserve (Tanzania), we studied how enrichment planting of A. stuhlmannii seeds affected germination and establishment rates under varying local levels of seed abundance and rodent activity. Overall, germination and establishment rates were high (4.8% and 2.2%, respectively, after 11 months), while local ecological conditions had a short lived (1–2 weeks) and unexpectedly small influence on the persistence of planted seeds. Given these rates, we estimate a cost of approximately US$0.14 per seedling. Enrichment planting of seeds, across a range of local ecological conditions, appears to be a viable and cost effective management strategy for increasing A. stuhlmannii recruitment in harvested areas.

Keywords

• Recruitment
• East Usambara Mountains
• Eastern Arc Mountains
• Cricetomys
• Germination
• Seed fate