Data from: Are the radiations of temperate lineages in tropical alpine ecosystems pre-adapted?

Aim: Tropical mountains around the world harbour an extraordinarily rich
pool of plant species and are hotspots of biodiversity. Climatically, they
can be zoned into montane climates at mid-altitudes and tropical alpine
climates above the tree line. Around half of the tropical alpine species
belong to plant lineages with a temperate ancestry, although these regions
are often geographically distant. We test the hypothesis that these
temperate lineages are pre-adapted to the tropical alpine climate.
Location: New World, with a focus on tropical alpine Andes. Time period:
Miocene to present. Major taxa studied: Flowering plants. Methods: We
build multidimensional environmental models representing the full space of
New World climates. We quantify the environmental similarity between the
tropical alpine ecosystem and those of potential source areas, while
correcting for regional differences by kernel density smoothers. Based on
spatial observations of the genus Hypericum (St John's Wort), we
quantify niche overlap and test for niche conservatism following
intercontinental dispersal using density-weighted nonparametric tests. A
dated species tree, biogeographical estimation, multi-optima
Ornstein–Uhlenbeck models and model selection approaches are used to test
for niche shifts during establishment in the tropical alpine Andes.
Results: The tropical alpine ecosystem is isolated by its climate from
adjacent regions and is climatically similar to temperate lowland biomes
of both hemispheres. Niche conservatism is evident in the study group,
except in the tropical alpine lineage that is characterized by niche
expansion and shifts in temperature optima. Main conclusions: Our results
reject the pre-adaptation hypothesis and instead suggest pronounced niche
evolution during colonization of tropical alpine ecosystems. Establishment
involved substantial niche shifts, mainly in temperature-related
variables, and resulted in a tremendous proliferation of species in the
newly invaded tropical alpine ecosystem.