Implications for estimating processes from Earth System Models
These results have important implications for the use of earth system
models (ESMs) for estimating ecosystems processes across scales. Most
ESMs treat traits as constants, disregarding variation among species
within plant functional types and intraspecific variation driven by the
environment (Ghimire et al., 2016, Lawrence et al., 2019, but see
attempts at integrating more flexible strategies like Fisher et al.,
2015). This was justified by previous evidence suggesting that only
interspecific variation mattered at continental scales (Messier et al.
2010). However, our results demonstrate that even at near-continental
scales intraspecific variation holds meaningful information that needs
to be addressed (Figures 1, 5). The need to incorporate intraspecific
variation is magnified when models are applied at smaller scales where
the environment affects traits-tradeoffs to move away from the global
LES (Fisher et al., 2018). Because different regions exhibit different
directional shifts from the species-only models (Figure 4) we need to
understand environmentally driven intraspecific traits variation to
accurately model regional ecosystem processes.