Fire-Stimulated Flowering: A Review and Look to the Future

The literature on fire-stimulated flowering is reviewed in terms of post-fire flowering patterns, proximal ultimate factors that affect flowering of plants post-fire, as well as application of evolutionary theory and development of evolutionary models in relation to fire-stimulated flowering. Consideration is given to the concepts involved, available empirical information, and areas that warrant further research. Understanding the factors responsible for fire-stimulated flowering is limited. Studies suggest factors involved, but confounding of variables prevents their separation. Experiments evaluate different factors, but there have been few such studies and little consideration regarding soil attributes, synergistic effects of multiple factors, and large-scale factors such as herbivory, florivory, seed dispersal, and pollination. Understanding the adaptive nature, and hence evolution, of fire-stimulated flowering is poor. Prevalence of particular fire-related responses has been related to geographical and other patterns, with deduction of adaptive nature of plant responses to fire and factors driving evolution of these responses. However, confounding of factors hinders this approach and can lead to disagreement between researchers. A better approach would be to hypothesize that evolution has resulted in plant responses to fire that are Evolutionarily Stable Strategies and to develop consequent mathematical models for such evolution, leading to predictions and tests. However, this approach requires quantitative assessment of responses to fire-related factors and influences of such responses on plant fitness, and so far few such assessments exist. This poor state of knowledge regarding plants with fire-stimulated flowering means that we cannot easily replace or enhance fire for managing species with fire-stimulated flowering, as sometimes necessary, and it also restricts their commercial cultivation. Experimental evaluation of plant responses to fire and development of evolutionary models is required. Our knowledge of the factors that trigger post-fire flowering by re-sprouting plant species remains poor, and so we cannot incorporate relationships between them and plant fitness into mathematical models of plant evolution.