Code from: A theoretical framework for trait-based eco-evolutionary dynamics: population structure, intraspecific variation, and community assembly

How is trait diversity in a community apportioned between and within
co-evolving species? Disruptive selection may result in either a few
species with large intraspecific trait variation (ITV) or many species
with different mean traits but little ITV. Similar questions arise in
spatially structured communities: heterogeneous environments could result
in either a few species that exhibit local adaptation or many species with
different mean traits but little local adaptation. To date, theory has
been well-equipped to either include ITV or to dynamically determine the
number of coexisting species, but not both. Here, we devise a theoretical
framework that combines these facets, and apply it to the above questions
of how trait variation is apportioned within and between species in
unstructured and structured populations, using two simple models of
Lotka-Volterra competition. For unstructured communities, we find that as
the breadth of the resource spectrum increases, ITV goes from being
unimportant to crucial for characterizing the community. For spatially
structured communities on two patches, we find no local adaptation,
symmetric local adaptation, or asymmetric local adaptation depending on
how much the patches differ. Our framework provides a general approach to
incorporate ITV in models of eco-evolutionary community assembly.