Dynamics of growth, death, and resource competition in sessile organisms

TL;DR

This paper presents a minimal dynamical model explaining how growth, death, and resource competition shape spatial and temporal patterns in sessile organisms, unifying diverse ecological phenomena.

Contribution

It introduces a unified minimal model linking individual metabolic growth, competition, and population patterns across various sessile species.

Findings

Population size distribution depends on growth and death rates.

Resource competition influences spatial pattern formation.

Asymmetric competition causes population shock waves similar to forest data.

Abstract

Population-level scaling in ecological systems arises from individual growth and death with competitive constraints. We build on a minimal dynamical model of metabolic growth where the tension between individual growth and mortality determines population size distribution. We include resource competition based on shared capture area separately. By varying relative rates of growth, death, and competitive attrition, we connect regular and random spatial patterns across sessile organisms from forests to ants, termites, and fairy circles. Then, we consider transient temporal dynamics in the context of asymmetric competition that primarily weakens the smaller of two competitors such as canopy shading or large colony dominance. When such competition couples slow timescales of growth with fast competitive death, it generates population shock waves similar to those observed in forest demographic data. Our minimal quantitative theory unifies spatiotemporal patterns across sessile organisms through local competition mediated by the laws of metabolic growth which in turn result from long-term evolutionary dynamics.