Plants Replacing Plants: The Future of Community Modeling and Research

Over the past few decades, several conceptual and mathematical models of plant community organization and dynamics have been put forward. While each of these models has attempted to explain important plant community patterns by attributing them to some aspect of plant niches, or to a higher-level process, their predictive success has been very limited. Here I explore why this has happened by reviewing and summarizing each model individually by highlighting the plant community pattern each is trying to explain and predict, by identifying the mechanisms, tolerances, and/or processes authors propose are producing those patterns and describing how they work within the model, and by examining the assumptions of each model. I then discuss common misconceptions and shortcomings among the models, and finally propose a unifying synthesis and comprehensive framework that can serve as a basis for future plant community modeling and research. This synthesis is composed of three key ideas (1) that plant-plant replacements are the “fundamental process” of plant communities which produce every community-level terrestrial plant pattern, (2) that plants respond to mechanisms and tolerances which work both in spaces inside plants and in those spaces outside plants that influence them and/or they may be able to influence, and (3) that those responses make up plant niches which may be able to predict how plants replace themselves over time and space. Consequently I suggest to future field researchers that the best way to understand plant community patterns is to study plant-plant replacements, first by sampling long-term vegetation plots in order to map them, and then by manipulating mechanisms and tolerances in field experiments in order to understand what causes them.