Spatial Variance in Ecology

Spatial variance of observed measures such as density is no longer viewed as a statistical annoyance. It is now treated as a biologically important quantity that changes value depending on the scale of measurement. Processes that generate spatial variance are often inferred by matching scales of maximum biological spatial variance to dominant physical processes at the same scale. Success in this approach has been limited to patchiness of plant communities along environmental gradients and to patchiness of passive aquatic organisms relative to physical flow structures. Some progress in formalizing spatial variance has been made using empirical models derived from quantitative descriptions of pattern, but further progress requires theoretical models of spatial variance and processes that generate variance as a function of spatial scale.