Determinants of Woody Cover in African Savannas

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dc.creatorSankaran, Mahesh
dc.creatorHanan, Niall P.
dc.creatorScholes, Robert J.
dc.creatorRatnam, Jayashree
dc.creatorAugustine, David J.
dc.creatorCade, Brian S.
dc.creatorGignoux, Jacques
dc.creatorHiggins, Steven I.
dc.creatorLe Roux, Xavier
dc.creatorLudwig, Fulco
dc.creatorArdo, Jonas
dc.creatorBanyikwa, Feetham F.
dc.creatorBronn, Andries
dc.creatorBucini, Gabriela
dc.creatorCaylor, Kelly K.
dc.creatorCoughenour, Michael B.
dc.creatorDiouf, Alioune
dc.creatorEkaya, Wellington
dc.creatorFeral, Christie J.
dc.creatorFebruary, Edmund C.
dc.creatorFrost, Peter G. H.
dc.creatorHiernaux, Pierre
dc.creatorHrabar, Halszka
dc.creatorMetzger, Kristine L.
dc.creatorPrins, Herbert H. T.
dc.creatorRingrose, Susan
dc.creatorSea, William
dc.creatorTews, Jörg
dc.creatorWorden, Jeff
dc.creatorZambatis, Nick
dc.date2016-09-21T17:08:22Z
dc.date2016-09-21T17:08:22Z
dc.date2005
dc.date.accessioned2018-03-27T08:55:43Z
dc.date.available2018-03-27T08:55:43Z
dc.descriptionFull text can be accessed at http://www.nature.com/nature/journal/v438/n7069/full/nature04070.html
dc.descriptionSavannas are globally important ecosystems of great significance to human economies. In these biomes, which are characterized by the co-dominance of trees and grasses, woody cover is a chief determinant of ecosystem properties1, 2, 3. The availability of resources (water, nutrients) and disturbance regimes (fire, herbivory) are thought to be important in regulating woody cover1, 2, 4, 5, but perceptions differ on which of these are the primary drivers of savanna structure. Here we show, using data from 854 sites across Africa, that maximum woody cover in savannas receiving a mean annual precipitation (MAP) of less than ~650 mm is constrained by, and increases linearly with, MAP. These arid and semi-arid savannas may be considered ‘stable’ systems in which water constrains woody cover and permits grasses to coexist, while fire, herbivory and soil properties interact to reduce woody cover below the MAP-controlled upper bound. Above a MAP of ~650 mm, savannas are ‘unstable’ systems in which MAP is sufficient for woody canopy closure, and disturbances (fire, herbivory) are required for the coexistence of trees and grass. These results provide insights into the nature of African savannas and suggest that future changes in precipitation6 may considerably affect their distribution and dynamics.
dc.identifierSankaran, M., Hanan, N.P., Scholes, R.J., Ratnam, J., Augustine, D.J., Cade, B.S., Gignoux, J., Higgins, S.I., Le Roux, X., Ludwig, F. and Ardo, J., 2005. Determinants of woody cover in African savannas. Nature, 438(7069), pp.846-849.
dc.identifierhttp://hdl.handle.net/20.500.11810/4111
dc.identifier10.1038/nature04070
dc.identifier.urihttp://hdl.handle.net/20.500.11810/4111
dc.languageen
dc.titleDeterminants of Woody Cover in African Savannas
dc.typeJournal Article, Peer Reviewed

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