Phylogenetic niche conservatism and the evolutionary basis of ecological speciation

Abstract

Phylogenetic niche conservatism (PNC) typically refers to the tendency of closely related species to be more similar to each other in terms of niche than they are to more distant relatives. This has been implicated as a potential driving force in speciation and other species-richness patterns, such as latitudinal gradients. However, PNC has not been very well defined in most previous studies. Is it a pattern or a process? What are the underlying endogenous (e.g. genetic) and exogenous (e.g. ecological) factors that cause niches to be conserved? What degree of similarity is necessary to qualify as PNC? Is it possible for the evolutionary processes causing niches to be conserved to also result in niche divergence in different habitats? Here, we revisit these questions, codifying a theoretical and operational definition of PNC as a mechanistic evolutionary process resulting from several factors. We frame this both from a macroevolutionary and population-genetic perspective. We discuss how different axes of physical (e.g. geographic) and environmental (e.g. climatic) heterogeneity interact with the fundamental process of PNC to produce different outcomes of ecological speciation. We also review tests for PNC, and suggest ways that these could be improved or better utilized in future studies. Ultimately, PNC as a process has a well-defined mechanistic basis in organisms, and future studies investigating ecological speciation would be well served to consider this, and frame hypothesis testing in terms of the processes and expected patterns described herein. The process of PNC may lead to patterns where niches are conserved (more similar than expected), constrained (divergent within a limited subset of available niches), or divergent (less similar than expected), based on degree of phylogenetic relatedness between species.

Environmental control of asexual reproduction and somatic growth of Aurelia spp. (Cnidaria, Scyphozoa) polyps from the Adriatic Sea

“…Further investigations on the eco-physiological tolerance and ontogenetic potentials of polyp stages may improve our knowledge on the mechanisms underlying the biogeographic distribution of extant representatives of the Aurelia species complex, facilitating design and implementation of management and mitigation measures against potential impacts of jellyfish blooms. Also, the concept of phylogenetic niche conservatism [41] assumes that closely related species, due to a longer evolutionary history in common, tend to be more similar in terms of ecological niche requirements than distantly related species [42]. This can be considered as a potential evolutionary driving force, with both morphology and ecological requirements as lineage-specific evolving traits, leading to divergence associated to reproductive isolation and, eventually, speciation.…”

Avian SDMs: current state, challenges, and opportunities

“…More specifically, phylogenetic niche conservatism assumes species to be ecologically more similar to each other than can be expected based on their phylogenetic relationships (Losos 2008a). There has been a contentious debate on whether niche conservatism should be considered mainly as a pattern (Losos 2008a, see also Losos 2008b or a process (Wiens and Graham 2005, Wiens 2008, Pyron et al 2015. While we do not aim to repeat this debate, we underline the opportunities that studies on niche evolution offer for our understanding of fundamental evolutionary patterns and processes (Wiens et al 2010), and call for caution concerning different definitions as well as practical pitfalls (Münkemüller et al 2015).…”

Computational biomechanics changes our view on insect head evolution

“…In our case, the configuration of the anterior tentorial pit (character 50 in electronic supplementary material, table S4), the presence of an anterior mandibular joint (char 68), and the configuration of the posterior mandibular joint (char 71) may constitute such plesiomorphic characters which are, according to our data, mechanically interdependent on each other and thus show concerted plesiomorphy [64]. Concerted plesiomorphy-the retention of ancestral states in groups of characters-is a term introduced as the essential effect underlying phylogenetic niche conservatism [75][76][77][78]. Thus, with a biomechanical testing of character interdependency we should also be able to better explain the morphological basis of phylogenetic niche conservatism [77].…”