Ecological issues by Alan R Pierce and Patricia Shanley
In general, when non-timber forest products are properly managed, they protect many forest services (eg hydrological functions, aesthetics, soil retention and carbon sequestration) and cause less biotic impoverishment than other land uses (Peters, 1994; Nepstad et al, 1992). This observation, however, must be tempered by the sheer variety of non-timber forest products and NTFP production systems. Some intensively managed NTFP production systems result in localized loss of biodiversity. Thiollay (1995) found that avian species richness, diversity and equitability was significantly lower in Sumatran agroforestry systems producing rubber (Hevea brasiliensis), damar (Shorea javanica) and durian (Durio zibethinus) than in primary forests. As
reported in the maple syrup (Acer saccharum) and benzoin (Styrax spp.) species profiles in Chapters 15 and 23, intensive production of these exudates may also lead to forest simplification and loss of diversity. Yet, in comparison to other land uses, NTFP management can play a positive role in forest conservation. From the Dayak forest fruit gardens (tembawangs – see de Jong, 1995) of Kalimantan, Indonesia, to the silvopastoral (dehesas) systems of the Mediterranean (see the Mediterranean species profiles in Chapter 17), NTFP management supports the maintenance of forests and many of their attendant ecosystem services. While some might not consider silvopastoral systems as ‘true forests’, such systems do provide important ecological services, help maintain biodiversity and are perceived as stable ecological systems by local environmentalists (Moussouris, 1999).