Walter's two-layer hypothesis revisited: back to the roots!

ABSTRACT: Walter (Jahrb Wiss Bot 87:750-860, 1939) proposed a two-layer hypothesis, an equilibrium explanation for coexistence of savanna trees and grasses. This hypothesis relies on vertical niche partitioning and assumed that grasses are more water-use efficient than trees and use subsurface water while trees also have access to deeper water sources. Thus, in open savannas, grasses were predicted to predominate because of their water use efficiency and access to subsurface water. This hypothesis has been a prominent part of the savanna literature since first proposed. We review the literature on Walter's hypothesis and reconsider his original intentions. Walter intended this hypothesis to be restricted to dry savannas. In his opinion, mesic and humid savannas were controlled by biotic factors and

SUBMITTER: Ward D 

PROVIDER: S-EPMC3679411 | biostudies-literature | 2013 Jul

REPOSITORIES: biostudies-literature