[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Bird diversification through time

From: Ben Creisler

An advance online paper  Nature. Some news stories came out yesterday.

W. Jetz, G. H. Thomas, J. B. Joy, K. Hartmann & A. O. Mooers (2012)
The global diversity of birds in space and time.
Nature (advance online publication)

Current global patterns of biodiversity result from processes that
operate over both space and time and thus require an integrated
macroecological and macroevolutionary perspective. Molecular time
trees have advanced our understanding of the tempo and mode of
diversification and have identified remarkable adaptive radiations
across the tree of life. However, incomplete joint phylogenetic and
geographic sampling has limited broad-scale inference. Thus, the
relative prevalence of rapid radiations and the importance of their
geographic settings in shaping global biodiversity patterns remain
unclear. Here we present, analyse and map the first complete dated
phylogeny of all 9,993 extant species of birds, a widely studied group
showing many unique adaptations. We find that birds have undergone a
strong increase in diversification rate from about 50 million years
ago to the near present. This acceleration is due to a number of
significant rate increases, both within songbirds and within other
young and mostly temperate radiations including the waterfowl, gulls
and woodpeckers. Importantly, species characterized with very high
past diversification rates are interspersed throughout the avian tree
and across geographic space. Geographically, the major differences in
diversification rates are hemispheric rather than latitudinal, with
bird assemblages in Asia, North America and southern South America
containing a disproportionate number of species from recent rapid
radiations. The contribution of rapidly radiating lineages to both
temporal diversification dynamics and spatial distributions of species
diversity illustrates the benefits of an inclusive geographical and
taxonomical perspective. Overall, whereas constituent clades may
exhibit slowdowns, the adaptive zone into which modern birds have
diversified since the Cretaceous may still offer opportunities for

Press releases and new stories: