Beyond Species Richness: A Critical Narrative Review of Integrating Functional, Phylogenetic and Genetic Diversity into Plant Biodiversity Conservation
Akshay Kumar Verma *
PG Department of Botany, Sahibganj College, Sahibganj, Jharkhand-816109, India.
*Author to whom correspondence should be addressed.
Abstract
Background: Plant conservation has long relied on species richness, endemism and extinction risk to allocate protection, yet richness is an incomplete summary of what biodiversity loss removes. Functional diversity, phylogenetic diversity and within-species genetic diversity capture ecological strategies, evolutionary history and adaptive capacity, and the Kunming-Montreal Global Biodiversity Framework now commits Parties to maintaining genetic diversity within populations of wild and domesticated species.
Purpose and Scope: This review critically evaluates whether, and under which conditions, these three facets provide conservation information that species richness does not, and how far that information can be translated into protected-area design, species prioritisation, ex situ conservation, restoration and monitoring. The focus is on vascular plants, with evidence from other taxa used only where it resolves a methodological question.
Approach: Literature published from 1990 onwards was identified through structured searches of multidisciplinary scholarly indexes, institutional sources and citation chasing, followed by critical appraisal and thematic synthesis.
Principal Findings: Cross-facet congruence is scale-dependent and often weak. Global analyses of vegetation plots indicate that functional and phylogenetic diversity are largely decoupled in plant communities, species richness is a poor surrogate for genetic diversity, and hotspots of different facets overlap only partially. Experimental evidence supports a role for trait diversity in ecosystem functioning, whereas the predictive value of phylogenetic diversity is inconsistent once richness is controlled. Evidence that genetic erosion reduces plant population fitness is comparatively robust, and within-species genetic diversity can influence ecosystem processes.
Unresolved Questions: Major uncertainties concern trait and phylogenetic data gaps, the sensitivity of spatial priorities to methodological choices, the feasibility of effective population size indicators for long-lived plants, and the scarcity of long-term evidence linking multi-facet conservation to outcomes.
Implications: No single facet can stand in for the others. Integration is most defensible when each facet is assigned to the conservation objective it demonstrably informs and when uncertainty is carried explicitly into decisions.
Conclusion: Moving beyond species richness is justified by current evidence, but its operational benefits remain partly theoretical and require outcome-based evaluation.
Keywords: Conservation prioritisation, evolutionary distinctiveness, functional traits, genetic diversity indicators, intraspecific variation, Kunming-Montreal Global Biodiversity Framework, spatial phylogenetics, vascular plants