Hutchinson’s ecological niche for individuals

Abstract

We here develop a concept of an individualized niche in analogy to Hutchison’s population-level concept of the ecological niche. We consider the individualized (ecological) niche as the range of environmental conditions under which a particular individual has an expected lifetime reproductive success of ≥ 1. Our concept has primarily an ecological function, as it refers to the match of an individual phenotype to its contemporary environment (niche fit) while we discuss evolutionary fitness as an evaluative parameter of this fit. We address four specific challenges that occur when scaling the niche down from populations to individuals. In particular, we discuss (1) the consequences of uniqueness of individuals in a population and the corresponding lack of statistical replication, (2) the dynamic nature of individualized niches and how they can be studied either as time-slice niches, as prospective niches or as trajectory-based niches, (3) the dimensionality of the individualized niche, that is greater than the population niche due to the additional dimensions of intra-specific niche space, (4) how the boundaries of individualized niche space can be defined by expected lifetime reproductive success and how expected reproductive success can be inferred by marginalizing fitness functions across phenotypes or environments. We frame our discussion in the context of recent interest in the causes and consequences of individual differences in animal behavior.

Integrating isotopic and nutritional niches reveals multiple dimensions of individual diet specialisation in a marine apex predator

“…performance surfaces mapped over N‐space; Simpson et al, 2004 ) could establish such links in field‐based contexts. Doing so would help better define animals' fundamental dietary niches as the breadth of nutrient intakes over which performance/fitness is maintained, which is critical for understanding individual/species' resiliencies to environmental variation or disturbance (Machovsky‐Capuska, Senior, et al, 2016b ; also see Takola & Schielzeth, 2022 ).…”

“…Moreover, establishing interrelationships in specialisations across different niche spaces (e.g. δ‐, p‐ and N‐space), and their hierarchical partitioning between individuals and species/populations, is necessary for enhancing our understanding of key ecological processes (Carscadden et al, 2020 ; Takola & Schielzeth, 2022 ). For instance, examining interplays between variation in food use and nutrient acquisition can reveal animals' nutritional priorities and how physiological requirements are met under ecological constraints (e.g.…”

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

“…Individuals that differ from each other will, in the very same environment, experience different effects of environmental conditions, consume different resources, have different interactions with conspecifics, and so on, and these interactions can have different fitness effects (Krüger et al 2021 [https://doi. org/10.32942/osf.io/7h5xq; preprint: not peer reviewed], Takola and Schielzeth 2022).…”

“…In contrast, the fundamental population niche excludes competition between populations. Some authors proposed to use the term potential individualized niche instead of fundamental individualized niche to emphasize the difference from Hutchinson's fundamental niche (Takola and Schielzeth 2022).…”

“…There are two important consequences of recognizing individualized niches in addition to population niches. First, individuals have an additional set of niche dimensions based on social interactions, as is highlighted in the concept of the social niche (Saltz et al 2016, Takola andSchielzeth 2022). Second, recognizing individualized niches allows individual differences to inform both theoretical and empirical research in ecology and evolution (Bolnick et al 2003, Dall et al 2012, Violle et al 2012.…”