Evidence for allelopathy as a mechanism of community composition change by an invasive exotic shrub, Chrysanthemoides monilifera spp. rotundata

• Published in: Plant and soil Vol. 316; no. 1-2; pp. 125 - 137
• Main Authors: Ens, E. J, French, K, Bremner, J. B
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.03.2009; Springer; Springer Netherlands; Springer Nature B.V
• Subjects: Acid soils; Agronomy. Soil science and plant productions; Allelopathy; Animal, plant and microbial ecology; Bioassay; Biological and medical sciences; Biomedical and Life Sciences; Chemical ecology; Chemical interference competition; Community ecology; community structure; Ecology; Exotic plant invasion; Fundamental and applied biological sciences. Psychology; Leaves; Life Sciences; Non-polar compounds; Nonnative species; Plant biology; Plant Physiology; Plant roots; Plant Sciences; Plants; Regular Article; Soil chemistry; Soil ecology; Soil science; Soil Science & Conservation; Soil water; Community structure; Exotic plant invasion; Non-polar compounds; Chemical interference competition; Soil plant relation; Exotic plant invasion . Non-polar compounds
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-008-9765-3

Chemical interference is increasingly suggested as a mechanism facilitating exotic plant invasion and plant community composition. In order to explore this further, we employed a comprehensive extract-bioassay technique that facilitated detection and demarcation of phytotoxicity, direct allelopathy and indirect allelopathy of bitou bush (Chrysanthemoides monilifera spp. rotundata) compared to an indigenous dominant of the invaded system, acacia (Acacia longifolia var. sophorae). Extracts of the leaves and roots of both species exhibited phytotoxic effects against five indigenous plant species. Evidence for allelopathy between co-evolved indigenous plants was detected between acacia and Isolepis nodosa. Allelopathy between bitou bush and four indigenous plant species was also detected. Therefore we propose that both the acacia and bitou bush have the potential to chemically inhibit the establishment of indigenous plants. Eventual dominance of bitou bush is predicted, however, based on more ubiquitous effects on seedling growth.