How Individualized Niches Arise: Defining Mechanisms of Niche Construction, Niche Choice, and Niche Conformance

Abstract

Organisms interact with their environments in various ways. We present a conceptual framework that distinguishes three mechanisms of organism-environment interaction. We call these NC³ mechanisms: niche construction, in which individuals make changes to the environment; niche choice, in which individuals select an environment; and niche conformance, in which individuals adjust their phenotypes in response to the environment. Each of these individual-level mechanisms affects an individual's phenotype-environment match, its fitness, and its individualized niche, defined in terms of the environmental conditions under which the individual can survive and reproduce. Our framework identifies how individuals alter the selective regimes that they and other organisms experience. It also places clear emphasis on individual differences and construes niche construction and other processes as evolved mechanisms. The NC³ mechanism framework therefore helps to integrate population-level and individual-level research.

Keywords: habitat choice; individual differences; individualized niche; niche construction; phenotypic plasticity.

Figure 1.

NC³ mechanisms. (a) Three individuals, A, B and C are in the same environment. Each individual uses a different NC³ mechanism, resulting in a change of its phenotype–environment match. (b) Each NC³ mechanism involves a different focal activity. Focal individuals A, B, and C can make changes to the environment, select the environment, or adjust the phenotype in response to the environment. (b) is modified from Kaiser and Trappes (2022).

Figure 2.

NC³ mechanisms produce changes in the individualized niche. Simplified individualized niches, showing two possible phenotypes and their values for fitness or match (e.g., growth rate, fertilization success, performance) along a single niche dimension (e.g., temperature, food abundance). (a) Niche construction: An individual with phenotype P in environment 1 makes changes to its environment so that it becomes environment 2, thereby increasing the individual's fitness. (b) Niche choice: An individual with phenotype P in environment 1 selects environment 3, thereby increasing its fitness. (c) Niche conformance: An individual with phenotype P in environment 1 adjusts to phenotype Q, thereby increasing its fitness within environment 1.