Source
Takola & Schielzeth (2022), LIT-127 (Biology & Philosophy 37:25), read in full in NOTE-170. The online table of 36 niche definitions was not read.
What was actually shown
The definition (p. 5). The individualized niche is the range of environmental conditions that gives a particular individual an expected lifetime reproductive success of at least one surviving offspring, each offspring counted 0.5 per parent in outcrossers. It is ecological: LRS is the “currency of the phenotype-environment match”, and inheritance and relative fitness are excluded.
Uniqueness (pp. 6–8). At population level individuals are replicates, so a niche is a hypervolume. At individual level the realized niche is a point or small volume, and the potential niche is a space of outcomes that did not happen. NOTE-170 rates this strong, since it follows from the definitions (C2).
The fixes offered. Repeated measures with variance decomposition; marginalizing phenotype-by-environment fitness functions across individuals, treated as tokens of trait types; and experimental translocation, which covers few dimensions and is bounded by lifespan. The marginalization is shown only schematically (Fig. 2), with no data (NOTE-170, C3, weak).
The boundary (pp. 14–16). The boundary must be set by expected, not realized, LRS, and the paper concedes there is “no empirical solution” for separating an individual’s LRS into its stochastic and deterministic parts (p. 15). The isocline of 1 is preferred to 0 as a practical benchmark.
The authors’ verdict (p. 17). “We see our concept mostly of a metaphorical value.” The abstract does not say this.
What could have come out otherwise. The paper could have estimated a potential individualized niche for some real system. It does not, and it does not claim to.
What this does not say
- That individual niches cannot be studied. Realized, time-slice, prospective and trajectory-based niches are said to be quantifiable, and the potential niche to be partly inferable. The claim here is about what the “individual” in the estimate is.
- That it is a rebranding of individual-differences research. The paper distinguishes the two by the environment: the niche is a set of conditions, and the phenotype only mediates fit. NOTE-170 rates that distinction weak but does not reject it.
- Anything about evolution. Relative fitness and inheritance are excluded by design, so the account says nothing about how individualized niches evolve.
- That prospective niches only shrink. That claim (p. 10) assumes potentials are fixed at the zygote, and learning and reversible plasticity are not considered.
- That the token/type tension is the paper’s own finding. The paper does not confront it explicitly. It is NOTE-170’s reading of what marginalization across individuals implies.
Connections
- Trappes (LIT-169) restricts the comparison of niche construction theory to population niches and leaves open whether an individualized evolutionary niche exists. This paper supplies only an ecological one, so her question stays open. Its E[LRS] ≥ 1 boundary is the individual twin of the persistence criterion she uses. The two papers do not cite each other (NOTE-170, corrections).
- Baedke et al. (LIT-110) name individualized niches as where experiential niche construction should meet selection. This is the object they would need.
- No other THEORY in the record states a niche concept.