DOI: 10.5061/dryad.18931zctg
title: Data from: Convergent evolution of niche structure in Northeast Pacific kelp forests

description: Much of the morphological and ecological diversity present on earth is
 believed to have arisen through the process of adaptive radiation. Yet,
 this is seemingly at odds with substantial evidence that niches tend to be
 similar among closely related species (i.e., niche conservatism).
 Identifying the relative importance of these opposing processes in driving
 niche evolution under different circumstances is therefore essential to
 our understanding of the interaction between ecological and evolutionary
 phenomena. In this study, we make use of recent advances in our
 understanding of the phylogeny of kelps (Laminariales) to investigate
 niche evolution in one of the most ecologically significant groups of
 benthic habitat-forming organisms on the planet. We quantify functional
 traits and use community sampling data from a kelp diversity hotspot to
 determine which traits are responsible for the habitat (β) niche of kelps
 and whether they are labile or conserved across the kelp
 phylogeny.  We find that combinations of functional traits have
 evolved convergently across kelp subclades and that these functional
 traits are significant predictors of community structure. Specifically,
 traits associated with whole-kelp structural reinforcement and material
 properties were found to be significantly correlated with species
 distributions along a gradient of wave disturbance and thus predict the
 outcome of environmental filtering. However, kelp assemblages were made up
 of species that are more phylogenetically distinct than expected (i.e.,
 phylogenetic overdispersion), suggesting that niche partitioning along
 this gradient of wave disturbance has been an important driver of
 divergence between close relatives. These results are consistent with the
 hypothesis that environmental filtering associated with wave disturbance
 plays an essential role in determining the habitat niche of kelps across
 local communities and further suggest that this process can drive
 phenotypic divergence and niche partitioning between close relatives. We
 propose that parallel adaptive radiation of kelp subclades has shaped the
 diversity and species composition of kelp forests in the Northeast Pacific
 and we discuss how evidence from the literature on incipient or ongoing
 speciation events support this hypothesis.
description: The raw data provided are as follows: 1) phylogenetic
 tree -adopted from phylogenomic analysis of Starko et al., 2019 Mol. Phy.
 Evol. 136: 138-150, 2) a dataset of trait values collected from the field
 and literature, 3) a community matrix of species presence-absence at 87
 sites collected in 1995 as part of a Parks Canada survey led by L.Druehl
 and C.Elliot, 4) a dataset containing the upper limit of barnacles at 55
 sites which serves a proxy of wave exposure. A few additional files are
 included that represent analyses of these raw data. Descriptions of all
 files are given in the ReadMe. For more information on data collection and
 analysis, see Starko et al. 2020 Fun. Ecol. or contact SS directly:
 samuel.starko@gmail.com.
description: A description of fields within each data file can be found in the
 ReadMe file.