I wonder what species they used for their monoculture and their diverse treatments (fucking pay walls). If it was all grassy spp of the same height this would be really cool.
Not knowing what they used the findings aren’t that surprising given that if you h ave diversity, you are much more likely to to have structure (layers) in the vegetative community, and therefore greater canopy cover and overlap.
In winter, this still applies somewhat in terms of sheltering and catching snow which is more insulating.