Interference competition and invasion: Spatial structure, novel weapons and resistance zones

Abstract

Certain invasive plants may rely on interference mechanisms (allelopathy, e.g.) to gain competitive superiority over native species. But expending resources on interference presumably exacts a cost in another life-history trait, so that the significance of interference competition for invasion ecology remains uncertain. We model ecological invasion when combined effects of preemptive and interference competition govern interactions at the neighborhood scale. We consider three cases. Under "novel weapons," only the initially rare invader exercises interference. For "resistance zones" only the resident species interferes, and finally we take both species as interference competitors. Interference increases the other species' mortality, opening space for colonization. However, a species exercising greater interference has reduced propagation, which can hinder its colonization of open sites. Interference never enhances a rare invader's growth in the homogeneously mixing approximation to our model. But interference can significantly increase an invader's competitiveness, and its growth when rare, if interactions are structured spatially. That is, interference can increase an invader's success when colonization of open sites depends on local, rather than global, species densities. In contrast, interference enhances the common, resident species' resistance to invasion independently of spatial structure, unless the propagation-cost is too great. Increases in background mortality (i.e., mortality not due to interference) always reduce the effectiveness of interference competition.

Distribution patterns and associations of dominant tree species in a mixed coniferous-broadleaf forest in the Changbai Mountains

“…Therefore, some discrepancies with previous studies may exist in terms of spatial distribution patterns and spatial associations within lower height classes Zhang et al 2007;Zhang et al 2009). In addition, the spatial patterns of species may have been generated by the interplay of various factors, such as selective cutting (Lei et al 2007), forest fire (Yu et al 2009), physiological effects (Peres-Neto and Legendre 2010), and disturbance (Allstadt et al 2012). The assembly of long-term monitoring data should be a priority for future studies.…”

Chemical Cues Released by an Alien Invasive Aquatic Gastropod Drive Its Invasion Success

“…Classic works considered exploitative competition as the primary biotic factor influencing the success of non-native species in new environments [3]. However, recent studies have emphasised interference competition and facilitation [4], [5], as well as the importance of environmental factors that together may contribute towards invasion resistance [6].…”

Advances on Modelling Riparian Vegetation—Hydromorphology Interactions

“…In the model of Allstadt et al . (), interference mechanisms were modelled as a trade‐off with reproduction ability. Modelling results indicate that individual alien species do not gain advantage through interference because their rate of reproduction is too low for them to spread rapidly, but where they occur in clustered plant patches, there are enough propagules to compete with native species for open sites.…”