Multi-trait eco-evolutionary dynamics explain niche diversity and evolved neutrality in forests

An enduring challenge in ecology is to understand how diverse plant species coexist when competing for the same basic resources[1][1]–[4][2]. Two candidate frameworks for meeting this challenge currently exist in forest ecology. Niche-based approaches succeed in describing successional dynamics in response to recurrent disturbances[5][3]–[9][4]. Approaches based on Hubbell’s neutral theory describe abundance patterns in highly diverse communities[10][5]. Yet both theories are unsuccessful where their competitor is strong, highlighting an enduring need for reconciliation[11][6]–[13][7]. In fact, the perception that niche and neutral processes are incompatible may have arisen because both types of models have lacked some critical features of real forests. Here we report a productive reconciliation that arises from extending niche models to include three ubiquitous features of vegetation: (1) plant growth under light competition, (2) multiple trait-mediated tradeoffs in plant function, and (3) evolutionary community assembly. We show that fitness equivalence – which neutral theory controversially takes as an assumption[4][2],[12][8],[13][7]–[14][9] – naturally arises as a mechanistic outcome of niche differentiation, but only with...Continue Reading