Department of Mathematical Sciences

Permanent URI for this community

https://scholar.sun.ac.za/handle/10019.1/223

Browse

Browsing Department of Mathematical Sciences by Subject "Adaptive dynamics"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    The eco-evolutionary dynamics of mutualistic networks: from pattern of emergence to stability
    (Stellenbosch : Stellenbosch University, 2016-03) Minoarivelo, Henintsoa Onivola; Hui, Cang; Stellenbosch University. Faculty of Science. Dept. of Mathematical Sciences. Centre for Invasion Biology.
    ENGLISH ABSTRACT: Mutualistic interactions, such as the interactions between flowering plants and their pollinators are ubiquitous in nature. A community in which members are involved in multiple mutualistic interactions forms a mutualistic network. The structure of such a network exhibits well-organized pattern, suggesting that complex ecological and evolutionary processes underlie the assembly of mutualistic networks. Although significant development has recently been achieved in uncovering the structural patterns of mutualistic networks, understanding ecological and evolutionary mechanisms that contribute to the emergence of these patterns and the overall ecological and evolutionary stability of mutualistic communities stays a challenge. Addressing this challenge is the aim of this thesis. We develop a mathematical and simulation model of the ecological dynamics of population densities and the evolutionary dynamics of functional traits of a mutualistic community to deal with the problem. Based on the fact that ecological and evolutionary mechanisms are interdependent, we use the framework of adaptive dynamics. We found that the wellorganized structural patterns observed in mutualistic networks such as a high nestedness and high modularity can emerge when interactions are trait-dependent and the accessibility to intra and cross trophic resources controlled. Moreover, we found that mutualism plays a determinant role in sustaining evolutionary stability and the productivity of the community. However, the evolutionary trajectories of functional traits in a mutualistic community can experience bistability and bifurcation when mutualistic interactions are highly specialized. In this case, mutualism often creates opportunity empty niche for invasion. Biological invasions targeting a specific peak of empty niche could lead to a strong directional selection in the community. In addition, an introduced species that has a trait different from those of native species and a level of interaction specialization similar to that of the native species is more likely to invade. The structure of the recipient network, such as its nestedness or modularity, is not a primary determinant of invasibility compared to other measurements of network stability such as robustness, resilience and disruptiveness. Consequently, we argue that the interplay of ecological and evolutionary processes through trait-mediated interactions can shed light on important questions in mutualistic networks.