The Grime general model, also known as the CSR model, for evolutionary strategies in plants describes three adaptive strategies plants use to respond to constraints placed on survival and reproduction. It simplifies an array of limitations into the primary factors of **stress** and **disturbance** as the growth inhibitors for plants in a given environment. Stress is any condition that limits growth, such as lack of sunlight, water, or essential nutrients. Disturbance is any event that results in loss of biomass, either from animals or the environment. Habitats can thus be classed into four types: 1. low-stress/low-disturbance 2. low-stress/high-disturbance 3. high-stress/low-disturbance, and 4. high-stress/high-disturbance. Of these four, the first three may be considered as possible opportunities for habitat, as a highly disturbed area with low productivity factors will not yield. Over time, plants have adapted different strategies to cope with these factors. These have been generalized into the CSR model that classifies plants according to how they respond to environmental circumstances. In this model, three ecological histories define the life of the plant. - **C** stands for *competitive*, which classifies plants who succeed in optimum stable conditions: low disturbance, moderate stress. - **S** is for *stress-tolerant*, plants that have adapted to various conditions in unproductive habitats. High stress, moderate disturbance. - **R** for *ruderal*, plants that have adapted to high-disturbance conditions in habitats that are highly productive. Low-stress, moderate [[competition]]. ![[grimeModel.png]] Competitive plants are also sometimes referred to as *generalists*, stress-tolerant as *specialists*, and ruderals as *pioneers*. This model is influential in the developing concept of plant conservatism, in which plants are assigned a value based on their adaptation to a specific set of environmental stresses and disturbances. Understanding these classifications are useful for determining habitat conditions across a time span, and for evaluating the intactness of historical plant communities. There may be a fourth classification that I will call **A** for *anthropological* or *artificial*, plants that have responded to being propagated by humans. ## Thoughts A disturbance is not just an event but could also occur as an [[negatité|absence]]. An extinct species leaves a void in its ecosystem. The way it interacted with the world vanishes, prompting adjustments in its host ecosystem. The disappearance of a plant may alter the nutrient cycling of a patch of forest, as animals seeking out that plant no longer churn up the [[Soil MOC|soil]] in the act of foraging. ## Resources 1. [Basic Overview](https://www.ecologycenter.us/population-growth/the-grime-general-model-for-three-evolutionary-strategies-in-plants.html) 2. Grime, J. P. (1977). Evidence for the existence of three primary strategies in plants and its relevance to ecological and evolutionary theory. The american naturalist, 111(982), 1169-1194. 3. Grime, J.P. (1988). The C-S-R model of primary plant strategies — origins, implications and tests. In: Gottlieb, L.D., Jain, S.K. (eds) Plant Evolutionary Biology. Springer, Dordrecht. [DOI](https://doi.org/10.1007/978-94-009-1207-6_14)