Individual plants exist amidst a complex of interactions affected by biotic influences of neighbors, numerous environmental factors, and the interactions between these. Within an individual, multiple components interact in affecting growth and reproduction, constrained by genetics, development and environmental limitations. Individual plant components may be viewed in a source/sink framework to analyze the impact on whole plant function of alternative life forms, and coupled with some fitness criteria, projecting situations in which differing forms may be adaptive. This assumes a tightly-coupled set of components within individuals, linked by transport of materials and energy, with selection acting to foster whole-plant response. However individuals live within a community context with interactions at various spatial and temporal scales, and a mesh of intermediaries including mychorrizal associates that create feedbacks between individuals. Such feedbacks provide the possibility that some associations are not zero-sum, in that inclusion of certain components in a community lead to higher fitness for all individuals. The emerging field of community genetics has taken mostly a quantitative genetics perspective in analyzing community associations with emphasis on heritability at higher levels of organization than the individual.
Results/Conclusions
Alternative approaches to community structuring include expanding the mostly two-species interaction models that incorporate environmental factors in a competitive context, neighborhood-interaction approaches which include spatial effects on population-dynamics, and individual-based approaches with explicit spatial interactions. However, community development may also be viewed as arising from a mesh of interactions for which a cooperative game theory perspective is appropriate. This includes a two-tier set of interactions in which within-individual coalitions of components coordinate actions (mediated by hosts of biochemical intermediaries as proximate causes) and between-individual interactions lead to coalitions mediated by feedbacks arising from impacts of environmental factors operating at multiple scales. Multiple stable community states may result, even under a fixed set of environmental factors, as alternative solutions to the game. Similarly, multiple stable coordinated within-individual forms can arise. Here the environmental factors may be viewed as commodities held by different components (within-individuals or between individuals in the community context) with positive net system-wide transfers arising through developmental time. This common framework for within- and between-individual interactions accounting for multiple environmental factors can take community genetics research beyond the past focus on foundation species and their interactions.
