A conceptual framework for ecosystem stoichiometry: balancing resource supply and demand

TLDR

The development of ecological stoichiometry has focused on organisms and their interactions, with limited attention to comprehensive ecosystem stoichiometry at larger scales. The study develops a conceptual framework linking internal processes and exogenous factors in spatially and temporally linked ecosystems, and proposes future research directions to advance understanding of stoichiometric constraints on ecosystem structure and function. The framework modifies a graphical model of resource ratio competition to incorporate functional views of stoichiometric balance, exogenous factors, organismal patterns, and spatial linkages, thereby explaining how ecosystems respond to variable resource supply. The approach identified stoichiometric schemes that explain how ecosystems respond to variable resource supply.

Abstract

The development of ecological stoichiometry has centered on organisms and their interactions, with less emphasis on the meaning or value of a comprehensive ecosystem stoichiometry at larger scales. Here we develop a conceptual framework that relates internal processes and exogenous factors in spatially‐ and temporally‐linked ecosystems. This framework emerges from a functional view of ecosystem stoichiometry rooted in understanding the causes and consequences of relative stoichiometric balance, defined as the balance between ratios of resource supply and demand. We begin by modifying a graphical model based on resource ratio competition theory that relates resource supply and demand to ecosystem processes. This approach identified mechanisms, or stoichiometric schemes, through which ecosystems respond to variable resource supply. We expand this view by considering the effects of exogenous factors other then resource supply that comprise a stoichiometric template that influences stoichiometric balance within ecosystems. We then describe a number of examples of patterns in organismal stoichiometry in several types of ecosystems that illustrate stoichiometric schemes and factors that impinge directly on stoichiometric patterns. Next, we conduct an initial analysis of the stoichiometric effects of spatial linkages between ecosystems, and how those relate to boundary dynamics and hot spot development. We conclude by outlining research directions that will significantly advance our understanding of stoichiometric constraints on ecosystem structure and function.