Online electronic material for: Macroevolutionary dynamics of climatic niche space

How and why lineages evolve along niche space as they diversify and adapt
to different environments is fundamental to evolution. Progress has been
hampered by the difficulties of linking a robust empirical
characterization of species niches with flexible evolutionary models that
describe their evolution. Consequently, the relative influence of abiotic
and biotic factors remains poorly understood. Here we characterize
species’ two-dimensional temperature and precipitation niche space
occupied (i.e., species niche envelope) as complex geometries and assess
their evolution across all Aves using a model that captures heterogeneous
evolutionary rates on time-calibrated phylogenies. We find that extant
birds coevolved from warm, mesic climatic niches into colder and drier
environments and responded to the K-Pg boundary with a dramatic increase
in disparity. Contrary to expectations of subsiding rates of niche
evolution, our results show that overall rates have increased steadily,
with some lineages experiencing exceptionally high evolutionary rates,
associated with colonization of novel niche spaces, and others showing
niche stasis. Both competition- and environmental change-driven niche
evolution transpire and result in highly heterogeneous rates near the
present. Our findings highlight the growing ecological and conservation
insights arising from model-based integration of comprehensive
environmental and phylogenetic information.