Growth on a seascape
Variations at each node are governed by time-scales from growth, migration, and noise

However, variations of the mean
take the simpler form

Assuming that the growth rate is always sufficiently slow to allow for a quasi-static state, such that

'
provides a universal mechanism to the empirical Richards growth equation from spatio-temporal stochasticity:
.
Numerical simulations [D. Swartz, B. Ottino-Loffler, M. Kardar, PRE 105, 014417 (2022)] support this conclusion

The anomalous scaling of population variance with mean is known in ecology as
relating the scaling of variance of population to its mean (in space of time).
A potentially testable link between local population distributions, and a global growth exponent.
Numerical simulation of time evolution of the population density
Results of numerical simulations in one dimension:

and two dimensions:
