Abstract
A myriad of interactions exist between vegetation and local climate for
arid and semi-arid regions. Vegetation function, structure and
individual behavior have enormous impacts on carbon-water-energy
balances, which consequently influence local climate variability that,
in turn, feeds back to the vegetation. In this study, a conceptual
vegetation structure scheme is formulated and tested in a new
carbon-water-energy coupled model to explore the importance of
vegetation structure on equilibrium biomass states. Two different
strategies of vegetation adaptation to water stress are included.
Surface energy, water and carbon fluxes are simulated for a range of
vegetation structures across a precipitation gradient in West Africa and
optimal vegetation structures that maximize biomass for each
precipitation regime are determined. Under dry conditions vegetation
tries to maximize the Water Use Efficiency and Leaf Area Index as it
tries to maximize carbon gain. However, as the vegetation can also
engineer its environment by extracting water from the surrounding bare
soil (thereby forming patches of vertical vegetation) it can also
minimize its vegetation cover. With increasing precipitation, the
vegetation tries to maximize its cover as it then can reduce water loss
from bare soil while having maximum carbon gain due to a large Leaf Area
Index. The competition between vegetation and bare soil determines a
transition between a 'survival' regime to a 'growing' regime. The new
modeling framework is useful to represent the effects of dynamic
vegetation structure in coupled land-atmosphere feedback models.
Original language | English |
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Publication status | Published - 1 Apr 2013 |