(National Academy of Sciences, 2008) Badgley, Catherine; Barry, John; Morgan, Michele; Behrensmeyer, Anna K.; Cerling, Thure E.; Pilbeam, David
Geohistorical records reveal the long-term impacts of climate
change on ecosystem structure. A 5-myr record of mammalian
faunas from floodplain ecosystems of South Asia shows substantial
change in species richness and ecological structure in relation
to vegetation change as documented by stable isotopes of C and
O from paleosols. Between 8.5 and 6.0 Ma, C4 savannah replaced
C3 forest and woodland. Isotopic historical trends for 27 mammalian
herbivore species, in combination with ecomorphological data
from teeth, show three patterns of response. Most forest frugivores
and browsers maintained their dietary habits and disappeared.
Other herbivores altered their dietary habits to include
increasing amounts of C4 plants and persisted for >1 myr during
the vegetation transition. The few lineages that persisted through
the vegetation transition show isotopic enrichment of !13C values
over time. These results are evidence for long-term climatic forcing
of vegetation structure and mammalian ecological diversity at the
subcontinental scale.
