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Titolo:
Changes in density, biomass, seed production and soil seed banks of the non-native invasive plant, Chromolaena odorata, along a 15 year chronosequence
Autore:
Witkowski, ETF; Wilson, M;
Indirizzi:
Univ Witwatersrand, Dept Anim Plant & Environm Sci, Restorat & Conservat Biol Res Grp, Johannesburg, South Africa Univ Witwatersrand Johannesburg South Africa Johannesburg, South Africa
Titolo Testata:
PLANT ECOLOGY
fascicolo: 1, volume: 152, anno: 2001,
pagine: 13 - 27
SICI:
1385-0237(2001)152:1<13:CIDBSP>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
BIOLOGICAL INVASIONS; POPULATION-DYNAMICS; NATURE RESERVES; SOUTH-AFRICA; ALIEN; EUPATORIUM; SPREAD; FYNBOS; FIRE; WEED;
Keywords:
alien; fire; forest margins; integrated control; regeneration ecology; weed;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Witkowski, ETF Univ Witwatersrand, Dept Anim Plant & Environm Sci, Restorat & Conservat Biol Res Grp, PO Wits 2050, Johannesburg, South Africa Univ Witwatersrand PO Wits 2050 Johannesburg South Africa
Citazione:
E.T.F. Witkowski e M. Wilson, "Changes in density, biomass, seed production and soil seed banks of the non-native invasive plant, Chromolaena odorata, along a 15 year chronosequence", PLANT ECOL, 152(1), 2001, pp. 13-27

Abstract

The non-native invasive plant Chromolaena odorata (Asteraceae) was studiedat 6 sites, with a chronosequence of ages from <1 to greater than or equalto 15 years, at St Lucia, South Africa. C. odorata density, biomass, seed production and soil seed banks were quantified in three microsites: sun, semi-shade and shade. C. odorata density decreased with invasion age, apparently as a self-thinning process. Biomass per unit area and seed production/plant increased over the first 10 years, but declined greatly at greater than or equal to 15 years. C. odorata plants grew larger and had much greater seed production in the sun relative to semi-shade, with small plants producing few if any seeds in the shade. Seed production in the sun varied from 2000 (<1-year old site) to 260 000 (10 year) seeds m(-2) annum(-1). About 20-46% of seeds produced were germinable and showed the same trend with age of invasion, but was particularly low after greater than or equal to 15 years. Assessment of soil seed banks immediately prior to seed production (seedgreater than or equal to 10 months old), indicates that about 5-10% of seeds in the sun and 11-22% in the shade were still germinable, resulting in germinable seed densities of 12-385 and 158-511 m(-2), respectively (excluding the greater than or equal to 15-year old site). A greenhouse trial showed that burial of seeds, relative to those at the surface, and provision of less water, significantly improved seed persistence in the soil, while light intensity had no effect. Control of C. odorata is difficult due to rapid attainment of reproductive maturity, large production of wind-dispersed seeds and a short-term persistent seed bank. An integrated control strategy either excluding fire (coastal forest sites) or using fire prior to seed release in July/August to kill plants and soil-stored seeds immediately prior to seed production, together with biological, chemical and/or physical control, should be explored.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 14/07/20 alle ore 11:41:14