Clonal splitting in desert shrubs

Authors
Citation
Hj. Schenk, Clonal splitting in desert shrubs, PLANT ECOL, 141(1-2), 1999, pp. 41-52
Citations number
88
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology
Journal title
PLANT ECOLOGY
ISSN journal
1385-0237 → ACNP
Volume
141
Issue
1-2
Year of publication
1999
Pages
41 - 52
Database
ISI
SICI code
1385-0237(199904)141:1-2<41:CSIDS>2.0.ZU;2-8
Abstract
Axis splitting is a widespread phenomenon in desert shrubs, and has been re ported for shrubs from several plant families, both in old- and new-world d eserts. It is so common in dwarf shrubs of arid environments as to be a def ining characteristic of this growth form. Although anatomists described thi s phenomenon several decades ago, there has been only one ecological study of one species, Ambrosia dumosa. The anatomical nature of the various split ting mechanisms that have been found suggests axis splitting to be an extre me form of hydraulic segmentation. The adaptive advantage of clonal splitti ng in desert shrubs has yet to be determined, but it appears to be largely a risk-spreading mechanism that enables independent mortality of integrated hydraulic units (IHUs) or ramets. This should be especially advantageous i n heterogeneous, water-limited environments, where soil water occurs in poc kets too small to support a large shrub-genet. Clonal splitting may cause a n increase in intraclonal competition among ramets, but there are also indi cations that at least some species possess mechanisms to reduce competition by minimizing root system overlap among ramets. Many desert shrub species that undergo clonal splitting maintain a dense clump growth form, possibly because such a growth form has positive effects on water and nutrient statu s of the soil and long-term effects on other soil properties.