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Plant Ecological Strategies Shift Across the Cretaceous–Paleogene Boundary

Ben Creisler

A new non-dino paper in open access that may be of interest:

Benjamin Blonder, Dana L. Royer, Kirk R. Johnson, Ian Miller & Brian
J. Enquist (2014)
Plant Ecological Strategies Shift Across the Cretaceous–Paleogene Boundary.
PLoS Biol 12(9): e1001949.


The Chicxulub bolide impact caused the end-Cretaceous mass extinction
of plants, but the associated selectivity and ecological effects are
poorly known. Using a unique set of North Dakota leaf fossil
assemblages spanning 2.2 Myr across the event, we show among
angiosperms a reduction of ecological strategies and selection for
fast-growth strategies consistent with a hypothesized recovery from an
impact winter. Leaf mass per area (carbon investment) decreased in
both mean and variance, while vein density (carbon assimilation rate)
increased in mean, consistent with a shift towards "fast" growth
strategies. Plant extinction from the bolide impact resulted in a
shift in functional trait space that likely had broad consequences for
ecosystem functioning.

Author Summary

Sixty-six million years ago the Chicxulub bolide impacted the Earth,
marking the Cretaceous–Paleogene boundary (KPB). This event caused the
planet's most recent mass extinction, but the selectivity and
functional consequences of the extinction on terrestrial plants has
been largely unknown. A key untested hypothesis has been that a
subsequent impact winter would have selected against slow-growing
evergreen species, a possible cause of the modern dominance of
high-productivity deciduous angiosperm forests. We tested this
hypothesis using fossil leaf assemblages across a 2-million-year
interval spanning the KPB. We assess two key ecological strategy
axes—carbon assimilation rate and carbon investment—using leaf minor
vein density and leaf mass per area as proxies, respectively. We show
that species that survive the KPB have fast-growth ecological
strategies corresponding to high assimilation rates and low carbon
investment. This finding is consistent with impact winter leading to
the nonrandom loss of slow-growing evergreen species. Our study
reveals a dramatic example of the effect of rapid catastrophic
environmental change on biodiversity.


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