Phylogenetic signatures of facilitation and competition in successional communities

Abstract

Summary 1.The balance between facilitation and competition through time is at the core of models for successional dynamics. However, since the 1980s, the studies of facilitation have shifted away from successional processes. In a return to the traditional roots of the study of facilitation, we assessed the phylogenetic signatures of competition and facilitation in Mediterranean successional communities and compared them with those recently quantified in non-successional communities of the Mexican desert. 2. Based on previous work, we hypothesized that facilitation between distantly related lineages is an important driver of successional dynamics, as has been shown in non-successional systems. However, we also predicted that the balance between facilitation and competition will be different in successional systems because many species disappear from communities during the process of succession, which does not occur in non-successional systems. 3. We sampled plant species composition over a chronosequence of post-fire succession and predicted phylogenetic clustering in communities at the early stages caused by species that reproduce by seed ('seeders', belonging to a few specific families) being favoured by fire; overdispersion in intermediate stages driven by facilitation interactions among distantly related species; and randomness in the final stage caused by the competitive exclusion of pioneer species belonging to a few families and the survival of species in many other families. 4. In the pioneer stage, we found a random phylogenetic pattern because seeders and many resprouter species were present at this stage, indicating that autosuccession was also occurring. In intermediate phases, once pioneers had recruited into open spaces and facilitated late-successional species, most of which were ancient taxa originating during the Tertiary, phylogenetic overdispersion predominated. Finally, in the later stages competitive exclusion of pioneer species reduced phylogenetic diversity, leading to a random phylogenetic structure. 5. Synthesis. As previously found for non-successional communities, facilitation among distantly related lineages appeared to drive successional dynamics. However, subsequent competition reduced phylogenetic diversity during succession in this Mediterranean system, and some species disappeared from the community.

Phylogenetic relatedness as a tool in restoration ecology: a meta-analysis

“…Our analyses revealed that the minimum phylogenetic distance between both species to ensure survival should be around 100 Myr, but much longer (260 Myr) to minimize negative effects on density. Interestingly, this age falls within the range of mean phylogenetic distance between nurses and beneficiary plants found in natural communities (244-343 Myr; [28] and [29] for Mexican desert and Mediterranean shrub communities, respectively). Our results clearly show that complementing phenotypic with phylogenetic information is useful to predict the success of nurse-based restoration practices.…”

Phylogenetic diversity promotes ecosystem stability

“…However, an alternative to competition per se and not explicitly tested in these analyses, is that distantly related species are more likely to participate in facilitative interactions (Verdu et al 2009). Assemblages with facilitative interactions should be more stable since facilitation is known to be especially important at buffering populations against stressful environmental conditions that would normally reduce fitness (Maestre et al 2009).…”

Demographic drivers of successional changes in phylogenetic structure across life‐history stages in plant communities

“…Recent studies have shown that many processes can affect phylogenetic structure (Cavender-Bares et al 2009). For instance, facilitation among distantly related species appeared to be an important driver of phylogenetic diversity in arid plant communities in Central Mexico (Valiente-Banuet and Verdu´2007) and in Mediterranean successional communities (Verdu´et al 2009). Here, we further show that other ecological processes, occurring during the regeneration stage, also drive successional changes in phylogenetic structure.…”