Heterogeneous conservation corridors of remnant vegetation protect biodiversity in South African timber mosaics

Abstract It is urgent now to place greater emphasis on harmonising conservation of indigenous biodiversity with food and fibre production. This is especially important in countries like South Africa which support high levels of irreplaceable biodiversity. The local timber industry has responded to this challenge by retaining large-scale networks of conservation corridors of historic ecosystems in the forestry landscape. The corridors consist mostly of grassland, with patches of indigenous forest, thickets, wetlands, ponds, and rivers. The motivation is to future proof compositional and functional biodiversity for ecological resilience in these production environments in a rapidly changing world. We synthesise here the substantial evidentiary research on the effectiveness of conservation corridors in plantation forestry-dominated landscapes in the Maputaland-Pondoland-Albany biodiversity hotspot. We focus on six emergent themes: 1. corridor dimensions, orientation, and connectivity, 2. heterogeneity at different spatial scales, 3. maintaining aquatic and terrestrial habitat quality in the conservation corridors, 4. biodiversity value of conservation corridors relative to protected areas, 5. the plantation matrix, and 6. assessment of corridor network performance. Results show the importance of prioritising large, high quality conservation corridors, especially those with a high number of natural features and variety of environmental conditions, both terrestrial and aquatic. Alien clearing, grazing control, and appropriate fire regimes should be prioritised in these corridors. Where possible we need to retain, restore, or replicate the natural ecological regimes. Overall, this conservation approach in commercial forestry landscapes helps to conserve indigenous biodiversity and ecosystem integrity, improves connectivity across afforested landscapes while also having sustainable timber production, thereby safeguarding the resilience of these working landscapes well into the future.