Convergence, consilience, and the evolution of temperate deciduous forests
Journal
American Naturalist
Journal Volume
190
Journal Issue
S1
Pages
S87-S104
Date Issued
2017
Author(s)
Edwards E.J.
Chatelet D.S.
Chen B.-C.
Ong J.Y.
Tagane S.
Kanemitsu H.
Tagawa K.
Teramoto K.
Park B.
Chung K.-F.
Hu J.-M.
Yahara T.
Donoghue M.J.
Abstract
The deciduous habit of northern temperate trees and shrubs provides one of the most obvious examples of convergent evolution, but how did it evolve? Hypotheses based on the fossil record posit that deciduousness evolved first in response to drought or darkness and preadapted certain lineages as cold climates spread. An alternative is that evergreens first established in freezing environments and later evolved the deciduous habit. We monitored phenological patterns of 20 species of Viburnum spanning tropical, lucidophyllous (subtropical montane and warm temperate), and cool temperate Asian forests. In lucidophyllous forests, all viburnums were evergreen plants that exhibited coordinated leaf flushes with the onset of the rainy season but varied greatly in the timing of leaf senescence. In contrast, deciduous species exhibited tight coordination of both flushing and senescence, and we found a perfect correlation between the deciduous habit and prolonged annual freezing. In contrast to previous stepwise hypotheses, a consilience of independent lines of evidence supports a lockstepmodel in which deciduousness evolved in situ, in parallel, and concurrent with a gradual cooling climate. A pervasive selective force combined with the elevated evolutionary accessibility of a particular response may explain the massive convergence of adaptive strategies that characterizes the world’s biomes. © 2017 by The University of Chicago.
Subjects
Biome assembly; Climate change; Freezing tolerance; Leaf habit; Phylogeny; Viburnum
Other Subjects
climate; evolution; forest; plant leaf; season; tree; Biological Evolution; Climate; Forests; Plant Leaves; Seasons; Trees
Type
journal article