5. Case study: Assessment of Biodiversity Conservation Potential of ISFM in Northern Ghana
The primary biodiversity indicator selected for this case study was the effective diversity index, also known as Hill numbers (Hill, 1973), which express all entropy-based diversity measures as effective numbers of species. Because a single Hill number (e.g. species richness at q = 0 or Shannon diversity at q = 1) captures biodiversity at only one level of sensitivity to species abundances, Hill diversity profiles were employed to examine diversity across a range of q values, from rare-species-dominated communities (q = 0) to communities dominated by common species (q ≥ 2), up to q = 4. This approach allows detection of differences in community structure that may not be evident from a single diversity measure, as sites can exhibit identical values at one diversity order while differing substantially at others. Consequently, Hill diversity profiles were used instead of single Hill numbers to capture variation in species richness, evenness, and dominance across ISFM, conventional agriculture, and relatively undisturbed reference areas, thereby reducing bias associated with reliance on a single diversity order.