4.3 Climatic effects
We investigated the effect of climate on model-plant grassland community
traits in reference soil treatments. As indicated by our PCA analysis,
species were strongly correlated with the measured traits consistently
across sites, whereas climate segregation followed little to no pattern,
meaning climate demonstrated minimal correlation with plant traits.
Therefore, climate differences in the absence of soil differences did
not lead to the restructuring of plant trait hierarchies. This finding
was supported by our Random Forest analysis, leading us to reject our
hypothesis that climate is the primary driver of trait variability.
Instead, our results illustrate consistent responses across species even
in the face of high climatic variation. Since our community was selected
to minimize functional overlap, a naturally occurring community with
higher functional overlap may experience less distinct trait
differentiation due to direct competition. This could affect the
application of our climate results; however, the effects of soil
demonstrated no such role of functional groups in trait responses,
rather revealing high stochasticity. While the interactive role of soil
and climate on plant traits has been well documented in past
community-based studies (Sundert et al. 2021; He and Dijkstra 2014),
questions remain about how climate variation alone affects grassland
community structures. Overall community diversity and their constituent
species have a determinant role in ecosystem responses to climatic
changes (Hautier et al. 2015), meaning monoculture-based climate change
experiments may not accurately represent plant trait responses. With the
consistent species-species trait responses observed in our experiment, a
community-based approach may better capture predictive plant-trait
responses under a changing climate.