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Life history complementarity and the maintenance of biodiversity

Nature volume 618, pages 986–991 (2023)Cite this article

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Abstract

Life history, the schedule of when and how fast organisms grow, die and reproduce, is a critical axis along which species differ from each other1,2,3,4. In parallel, competition is a fundamental mechanism that determines the potential for species coexistence5,6,7,8. Previous models of stochastic competition have demonstrated that large numbers of species can persist over long timescales, even when competing for a single common resource9,10,11,12, but how life history differences between species increase or decrease the possibility of coexistence and, conversely, whether competition constrains what combinations of life history strategies complement each other remain open questions. Here we show that specific combinations of life history strategy optimize the persistence times of species competing for a single resource before one species overtakes its competitors. This suggests that co-occurring species would tend to have such complementary life history strategies, which we demonstrate using empirical data for perennial plants.

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Fig. 1: Life history differences among related, co-occurring species.
Fig. 2: Simulation supports theory, and data support importance of life history for species pairs.
Fig. 3: Complementarity boosts diversity, and competition filters effective population size.
Fig. 4: Life history strategies in a plant community are complementary, but not neutral.

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Data availability

Data needed to generate Figs. 2b and 4 are available in the publicly accessible COMPADRE database61. Synthetic matrices used to generate Figs. 2a and 3 have been uploaded to the Zenodo repository86.

Code availability

Code samples of both a pairwise competition model and the metacommunity model used to generate Fig. 3 are provided via the Zenodo repository86 as R scripts (R version 4.2.2 using reshape2 version 1.4.4, dplyr version 1.0.10, and tidyr version 1.2.1.). This upload also contains annotations to help viewers run the code and sample sets of properly formatted matrices.

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Acknowledgements

J.P.O. acknowledges the Simons Foundation Grant no. 376199, McDonnell Foundation Grant no. 220020439. We acknowledge helpful comments from M. Chytrý and D. Storch on co-occurring perennials in the Czech Republic. We acknowledge help from R. D’Andrea on formulating initial iterations of our model. Creative commons and public domain images: we acknowledge D. Loudermilk, who licensed the image used in Fig. 1 (CC BY-SA 4.0); J. Hollinger (CC BY 2.0), M. Garcia (CC BY-SA 3.0), B. Gaberscek (CC BY 2.5 Supplementary Information) and P. Filippov (CC BY-SA 4.0) for the four images and licenses in Fig. 2b, and the US Fish and Wildlife Service for the first three public domain images in Fig. 4a (photographer D. Bender), B. Peterson (CC BY-SA 2.0) for the fourth image in in Fig. 4a, and J. Horn (CC BY 4.0) for the final two images in Fig. 4a.

Author information

Authors and Affiliations

  1. Department of Plant Biology, University of Illinois, Urbana, IL, USA

    Kenneth Jops & James P. O’Dwyer

  2. Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA

    James P. O’Dwyer

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Contributions

K.J. and J.P.O. designed the project. K.J. and J.P.O. developed the simulation and analytical results, and K.J. analysed COMPADRE data. K.J. and J.P.O. interpreted the analyses and wrote the manuscript.

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Correspondence to Kenneth Jops or James P. O’Dwyer.

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Extended data figures and tables

Extended Data Fig. 1 Life History Complementarity, Fitness Differences, and Niche Differences.

In Panel A, we show the combined effects of fitness differences and life history strategy on pairwise competition. We take 3 pairs of species and vary the long-term growth rate λ of the competitor with the lower Ny value. The colors denote the set of species and the vertical lines show the predicted optimal value of λ to maximize persistence. The persistence time when λ = 1 is the same as that in the trials shown in the main text. This time increases as we approach the optimum identified in Supplementary Information Eq.(1) before decreasing for larger values of λ. Here we see that a) life history variation still affects persistence time when we relax the assumption of equal fitness and b) that a new persistence optimum is introduced by varying fitness between species in a community. Panel B demonstrates the interplay between niche differences and life history. Here we construct our model according to Supplementary Information Section 1.2 and vary λhigh across 10 pairs of matrices with varying levels of difference in their Ny values. As λhigh and thus our degree of niche differentiation increases, persistence times increase in tandem—i.e. niche differentiation boosts persistence, as expected. Across all of these trials, however, differences in Ny still influence persistence times, and optimal persistence is achieved when species have the closest values of Ny—our definition of life history complementarity. The “neutral” points represent trials where λhigh = λlow, analogous to the trials in the main text. The solid lines represent linear regressions for each λhigh value and the shaded regions represent 95% confidence intervals for these regressions. Error bars in both Panel A and Panel B show standard error across 500 numerical trials, centered on the mean across those trials.

Extended Data Fig. 2 Life History, Fitness, and Niche Differences.

In Extended Data Fig. 2 we compare the model results of Extended Data Fig. 1A with the results of a combined fitness, niche, and life history differences model. Triangular points show the same data as ED Fig. 1A and square points show the results of trials where λhigh is set to the same λ value as the lower Ny competitor’s fitness in the trials from 1A. The matrix pairs are the same for the two sets of trials. The solid and dashed lines are approximate spline fits to the data points and serve to guide the viewer to the overall trend. Partitioning the community into niches results in a higher persistence time optimum of λhigh and a slower approach to this optimum. Peak persistence times are similar across both implementations, shown by the y-axis maxima for each matrix pair. Most importantly, the signature of life history differences is clear—the broad comparisons of the pairs of curves of each color show that differences in effective population size significantly impact persistence times even in the presence of both fitness and niche differences. Error bars show standard error, centered at the mean, across 500 trials.

Supplementary information

Supplementary Information

Models for pairwise competition with fitness differences and niche differences.

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Jops, K., O’Dwyer, J.P. Life history complementarity and the maintenance of biodiversity. Nature 618, 986–991 (2023). https://doi.org/10.1038/s41586-023-06154-w

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