L16_Savannas_C3_C4_Photosynthesis_comp

438 p846 849 below map 600mm precipitaon amount

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: , deeply rooted trees can return groundwater back to the atmosphere biogeochemical cycles: •  grasses typically have higher net primary produc=vity (NPP) •  C4 grasses can photosynthesize under very low CO2 levels societal: •  biomass burning (wood, charcoal) an important energy resource in Africa. Also game meat, pastoralism. Ecological: •  plant/animal adapta=ons to closed, open and mixed savannas What determines woody cover in savanna ecosystems? Sankaran et al., 2005 Nature v.438, p.846- 849 What determines woody cover in savanna ecosystems? Fire? Herbivory? Soil water? related to water- holding capacity of soils Sankaran et al., 2005 Nature v.438, p.846- 849 What determines woody cover in savanna ecosystems? Are soil nutrients important? Sankaran et al., 2005 Nature v.438, p.846- 849 What determines woody cover in savanna ecosystems? Precipita=on ! Are soil nutrients important? Sankaran et al., 2005 Nature v.438, p.846- 849 Below MAP = ~600mm, precipita=on amount imposes an ‘upper limit’ on % woody cover. Other factors (fire, herbivory, soil quality) determine the actual % woody cover within the ‘allowed zone’ Sankaran et al., 2005 Nature v.438, p.846- 849 ‘forbidden’ zone ‘allowed’ zone Below MAP = ~600mm, precipita=on amount imposes an ‘upper limit’ on % woody cover. Other factors (fire, herbivory, soil quality) determine the actual % woody cover in the ‘allowed zone’ Sankaran et al., 2005 Nature v.438, p.846- 849 high woody cover low woody cover can these two situa=ons exist under iden=cal clima=c condi=ons? savannas: gray, ver=cal hatched, cross- hatched ‘stable’ savannas: gray ‘unstable’ savannas: ver=cal hatched ‘transi=onal’ savannas: cross hatched desert unstable: savannas that could turn into closed forest, or open grassland, depending on changes in fire,...
View Full Document

Ask a homework question - tutors are online