Abstract The niche concept is central to ecology, evolution, and conservation biology. To assess resource dynamics in biological communities, the most widely used niche metrics are niche breadth and niche overlap. Colwell and Futuyma (1971) were the first to propose niche metrics that incorporated resource distinctness. In their framework, niche breadth and overlap are calculated using either a relative weighting factor (d₉) d j or an absolute weighting factor (₉) δ j. Hanski (1978) later introduced an alternative weighting factor (₉^{* }) δ j ∗, which accounts for both the quality and quantity of resource states in niche calculations. However, metrics based on d₉ d j, ₉ δ j and ₉^* δ j ∗ have inherent mathematical and conceptual limitations. To overcome these issues, the present study introduces modified forms of these factors (ed₉ e d j, e₉ e δ j and e₉^* e δ j ∗) and evaluates their performance using eight hypothetical and one empirical (ecological) resource matrix. The findings indicate that niche metrics incorporating the ed₉ e d j factor represent the most coherent and biologically meaningful option.
Özkan et al. (2026) studied this question.