The nature of ecological conservatism: deconstructing the ecological and social foundations of Floristic Quality Assessment

Floristic Quality Assessment (FQA) is a set of metrics used to reflect the conservation value of vegetation and is used widely in restoration and environmental assessment. Underlying FQA metrics is the concept, known as ecological conservatism, that individual plant species have dissimilar fidelities to intact native ecosystems and tolerances to modern human impacts. Despite FQA metrics being popular in scientific and applied contexts, less attention has been paid to the underlying concept of conservatism. Definitions of conservatism vary, and its ecological correlates have never been rigorously summarized. We reviewed the FQA literature to address the questions: What information is captured by ecological conservatism, and is the concept meaningful beyond the FQA system? We synthesized evidence linking conservatism to slow life histories, ecological specialization, and rarity. However, conservatism is just as much a social concept as an ecological one, being fundamentally value-laden and espousing a narrow definition of conservation value. Its inherent subjectivity makes FQA more susceptible to bias and error. Conservatism operationalizes the concept of “ecological losers”—species that decline when faced with novel, hostile conditions. The idea arose from a practical need to protect biodiversity with limited data, leading practitioners to rely on expert—but subjective—knowledge. Thus, conservatism is a translational concept straddling ecology, natural history, and human values, making it particularly suited for conservation decision-making and ecological restoration.