Laboratory-based seed storage systems have been developed as an alternative to in situ conservation for indigenous
woody plant species. However, interactions between
seed quality and environmental variables must be known for each species prior to seed collection, storage and sowing
to ensure effective conservation. This study investigated
Acacia tortilis seed weight/quality patterns across seven Botswana seed provenances in relation to: soil nutrient status, altitude; latitude; slope angle; % grass cover; height
and density of other woody plants nearby. The higher
rainfall and relatively eutrophic seed provenances of northwestern
Botswana (Chobe, Okavango and Makgadikgadi)
were associated with large A. tortilis species and seeds, as
well as higher densities of woody plants. Spatial variation in seed weights of A. tortilis was principally a function of
rainfall and soil organic carbon. Although more work is required to establish the relationship between seed weight
and germination rates for A. tortilis, this research suggests
that seed collection should focus on sites with high levels of
rainfall and soil organic carbon.