Spatial arrangements affect suppression of invasive Alternanthera philoxeroides by native Hemarthria compressa

• Published in: Acta oecologica (Montrouge) 2014-08, Vol.59 (59), p.46-51
• Main Authors: Liao, Jianxiong, Tao, Min, Jiang, Mingxi
• Format: Article
• Language: English
• Subjects: Aggregation; Alternanthera philoxeroides; Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Biomass investment; Conservation, protection and management of environment and wildlife; Fundamental and applied biological sciences. Psychology; General aspects; Hemarthria; Interspecific encounters; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Relative yield; Replacement series
• ISSN: 1146-609X; 1873-6238
• DOI: 10.1016/j.actao.2014.05.010

It has been hypothesized that differences in spatial arrangements change the relative frequency of intra- and interspecific encounters between plant species. Manipulating spatial arrangement may play a role in invasive plant suppression when native species are used as competitors against introduced species. In this study, a replacement series experiment was performed to investigate the effects of intraspecifically random and aggregated spatial arrangements on interactions between the native plant Hemarthria compressa and the invasive plant Alternanthera philoxeroides, to test the possibility and effectiveness of H. compressa in suppressing A. philoxeroides. When both species were planted in intraspecifically random spatial patterns, H. compressa had a competitive advantage over A. philoxeroides at relative densities of 2:2 and 3:1. However, aggregation increased the strength, and therefore the cost, of intraspecific competition in H. compressa, resulting in lower biomass production, which reduced its effectiveness as an interspecific competitor. As the relative density of H. compressa in mixtures decreased, plants allocated more biomass to belowground parts, but fewer interspecific encounters lowered its inhibitory effects on A. philoxeroides. The results not only confirm that the frequency of conspecific and heterospecific encounters can influence competitive outcomes, but also suggest that a reduction in the degree of spatial aggregation in H. compressa and an increase in its relative densities may be essential to increase the suppression of A. philoxeroides. •The native competitive species can be used to suppress invasive species.•Spatial arrangements can affect competitive interactions and local dispersal.•The mechanism relies on relative frequency of intra- and interspecific encounters and available gaps.•Relative yield was used to evaluate the competitive outcomes.•Increasing information will help to control and management of invasive plants.