TY - JOUR

T1 - Intraspecific trait variation increases species diversity in a trait-based grassland model

AU - Crawford, Michael

AU - Jeltsch, Florian

AU - May, Felix

AU - Grimm, Volker

AU - Schlägel, Ulrike E.

N1 - Publisher Copyright: © 2018 The Authors

PY - 2019/3/1

Y1 - 2019/3/1

N2 - Intraspecific trait variation (ITV) is thought to play a significant role in community assembly, but the magnitude and direction of its influence are not well understood. Although it may be critical to better explain population persistence, species interactions, and therefore biodiversity patterns, manipulating ITV in experiments is challenging. We therefore incorporated ITV into a trait- and individual-based model of grassland community assembly by adding variation to the plants’ functional traits, which then drive life-history tradeoffs. Varying the amount of ITV in the simulation, we examine its influence on pairwise-coexistence and then on the species diversity in communities of different initial sizes. We find that ITV increases the ability of the weakest species to invade most, but that this effect does not scale to the community level, where the primary effect of ITV is to increase the persistence and abundance of the competitively-average species. Diversity of the initial community is also of critical importance in determining ITV's efficacy; above a threshold of interspecific diversity, ITV does not increase diversity further. For communities below this threshold, ITV mainly helps to increase diversity in those communities that would otherwise be low-diversity. These findings suggest that ITV actively maintains diversity by helping the species on the margins of persistence, but mostly in habitats of relatively low alpha and beta diversity.

AB - Intraspecific trait variation (ITV) is thought to play a significant role in community assembly, but the magnitude and direction of its influence are not well understood. Although it may be critical to better explain population persistence, species interactions, and therefore biodiversity patterns, manipulating ITV in experiments is challenging. We therefore incorporated ITV into a trait- and individual-based model of grassland community assembly by adding variation to the plants’ functional traits, which then drive life-history tradeoffs. Varying the amount of ITV in the simulation, we examine its influence on pairwise-coexistence and then on the species diversity in communities of different initial sizes. We find that ITV increases the ability of the weakest species to invade most, but that this effect does not scale to the community level, where the primary effect of ITV is to increase the persistence and abundance of the competitively-average species. Diversity of the initial community is also of critical importance in determining ITV's efficacy; above a threshold of interspecific diversity, ITV does not increase diversity further. For communities below this threshold, ITV mainly helps to increase diversity in those communities that would otherwise be low-diversity. These findings suggest that ITV actively maintains diversity by helping the species on the margins of persistence, but mostly in habitats of relatively low alpha and beta diversity.

KW - community assembly

KW - individual-based model

KW - intraspecific trait variation

KW - Biology

UR - http://www.scopus.com/inward/record.url?scp=85056200852&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/2059fd96-21e6-3262-9469-32b33d5c748f/

U2 - 10.1111/oik.05567

DO - 10.1111/oik.05567

M3 - Journal articles

AN - SCOPUS:85056200852

VL - 128

SP - 441

EP - 455

JO - Oikos

JF - Oikos

SN - 0030-1299

IS - 3

ER -