Plant Strategies Along Resource, Disturbance, and Temperature Gradients

Abstract

Abstract The classic fitness function of a trait is a unimodal curve, where there is a single trait value that optimizes fitness in a given environment and traits to either side of the peak confer weaker fitness benefits. However, multiple combinations of trait values can simultaneously optimize fitness in a given environment, and this changes the unimodal fitness function into a multimodal fitness function. Rapid acquisition of resources is critical for maintaining the high growth rates that are required to compete in a resource-rich environment. The difference between water and nutrient limitation is that water must be lost from the plant to photosynthesize, whereas nutrients can be reused and recycled. The vegetation canopy in productive environments will close given sufficient time after a disturbance, and canopy closure leads to light limitation. High-resource conditions following a disturbance will select for species with fast pace of life, low degrees of iteroparity, and short lifespans. Plants would be far more efficient in the absence of herbivores, but the benefits of defending themselves against being eaten are greater than the costs. There are two general mechanisms of persistence in crown fire regimes: resprouting from dormant meristems or seedling recruitment. In surface fire regimes, fire escapers grow tall and protect their lateral meristems with thick bark. Photosynthetic pathways and woody plant leaf habit are strong categorical determinants of distributions along minimum temperature gradients.