Not even wrong: Reply to Wagg et al

TL;DR

This paper clarifies misunderstandings about pairwise effects, null baselines, and nonlinearity in biodiversity-ecosystem functioning research, reaffirming the validity of previous claims and criticizing the Loreau-Hector partitioning scheme.

Contribution

The authors correct misconceptions about pairwise effects, null baselines, and nonlinearity, defending their original critique of the LH partitioning scheme and biodiversity-ecosystem functioning analysis.

Findings

Pairwise effects can be computed over any time horizon.

The midpoint of monocultures is a neutral community baseline.

Generalized diversity-interaction models do not solve nonlinearity issues in LH partitioning.

Abstract

We demonstrate that the issues described in the Wagg et al. (2019) Comment on our paper (Pillai and Gouhier, 2019) are all due to misunderstandings about the implications of pairwise effects, the nature of the null baseline in both our framework and in the Loreau-Hector (LH) partitioning scheme (i.e., the midpoint of the monocultures), and the impact of nonlinearity on the LH partitioning results. Specifically, we show that (i) pairwise effects can be computed over any time horizon and thus do not imply stable coexistence, (ii) the midpoint of the monocultures corresponds to a neutral community so coexistence was always part of the LH baseline, and (iii) contrary to what Wagg et al. suggested, generalized diversity-interaction models do not account for (and may in fact exacerbate) the problem of nonlinearity in monocultures, which inflates the LH net biodiversity effect and generates incorrect estimates of selection and complementarity. Hence, all of our original claims about the triviality inherent in biodiversity-ecosystem functioning research and the issues with the LH partitioning scheme hold.