Speaker
Description
The species abundance distribution (SAD) is a fundamental representation of biodiversity, describing both the number of species in a community and the allocation of individuals among them. In contrast to the species–area relationship (SAR), which is inherently scale-dependent, the SAD is typically examined at a fixed spatial scale, despite the fact that its form must vary with sampling extent. In this study, we explicitly frame the SAD as a scaling phenomenon. Building on order statistics, we introduce a set of functions $S_m(A)$, where $S_1(A)$ corresponds to the classical SAR and $S_m(A)$ denotes the number of species with at least $m$ individuals within area $A$. The abundance distribution at scale A can then be expressed as differences $C_m(A) = S_m(A) - S_{m+1}(A)$. We demonstrate that the functions $S_m(A)$ exhibit scaling behaviour analogous to the SAR, including three distinct regimes. When the corresponding $C_m(A)$ are visualized on a logarithmic scale, they tend to converge toward similar richness levels, though at progressively larger spatial scales. To our knowledge, this regularity has not been previously documented and points to a connection between the scaling of abundance distributions and the spatial arrangement of individuals within species. We further show that the approach of these scale-dependent SADs toward their large-area limit can be summarized through distance measures between distributions across scales, offering a coarse-grained characterization of convergence. Importantly, this behaviour depends on whether the sampled area captures the largest-scale regime of the SAR. Together, these findings highlight the inherently scale-dependent nature of the SAD and provide a unified framework for relating patterns of species abundance to spatial scaling in biodiversity.
| Status Group | Postdoctoral Researcher |
|---|---|
| FOR TALKS: Poster Presentation Option | No, I prefer to present only as a talk. |