Biology ETDs
Publication Date
Winter 11-14-2019
Abstract
The distribution of life across the Andes mountains reflects historical elevational-range contraction and expansion. Whereas contraction implies specialization, expansion requires overcoming hidden barriers. Three eco-evolutionary phenomena may drive patterns in rates of elevational range evolution: (1) The Dobzhansky-MacArthur Phenomenon (DMP) predicts lower rates of upward expansion with harsher physical conditions, while downward expansion increases with lower diversity; (2) the evolutionary tendency toward specialization predicts contraction increases when ranges are broad; and (3) natural selection for respiratory performance could suppress expansion across mid-elevations due to gene-environment mismatch. We modeled elevational range shifts of Neotropical landbirds. Contrary to the DMP, upward expansion rates increased with elevation, suggesting higher invasibility of depauperate communities. Downward expansion was constrained at mid-elevations the same elevations where hemoglobin predictably shifts in O2-binding affinity. However, even the relatively fast rates of upward expansion occurred five orders of magnitude slower than those predicted over the next century by escalator models.
Language
English
Keywords
macroevolution, evolution, biogeography, macroecology, high altitude adaptation, range evolution
Document Type
Thesis
Degree Name
Biology
Level of Degree
Masters
Department Name
UNM Biology Department
First Committee Member (Chair)
Christopher C. Witt
Second Committee Member
Jeffrey C. Long
Third Committee Member
Michael J. Andersen
Recommended Citation
Gadek, Chauncey. "Dynamics of Avian Elevational Ranges Reveal Hidden Evolutionary Forces." (2019). https://digitalrepository.unm.edu/biol_etds/334
Included in
Biodiversity Commons, Biology Commons, Evolution Commons, Ornithology Commons, Other Ecology and Evolutionary Biology Commons