Measuring the ecological outcomes of fire: metrics to guide fire management

Abstract Background Changes to fire regimes threaten biodiversity worldwide and emphasize the need to understand the ecological consequences of fire management. For fire management to effectively protect biodiversity, it is essential to have ecologicallyrelevant metrics to plan and evaluate management interventions. Here, we describe a suite of metrics to guide fire management for enhanced biodiversity outcomes. Results We define five metrics that collectively provide comprehensive and complementary insights into the effect of fire regimes on ecosystem resilience and components of biodiversity. These include (1) Species Habitat Availability, a measure of the amount of suitable habitat for individual species; (2) Fire Indicator Species Index, population trends for species with clear fire responses; (3) Vegetation Resilience, a measure of plant maturity and the capability of vegetation communities to regenerate after fire; (4) Desirable Mix of Growth Stages, an indicator of the composition of post-fire age-classes across the landscape; and (5) Extent of High Severity Fire, a measure of the effect of severe fire on post-fire recovery of treed vegetation communities. Each metric can be quantified at multiple spatial and temporal scales relevant to evaluating fire management outcomes. We present a case study from Victoria, Australia, in which two metrics are applied across spatially-nested management areas. Results highlight four characteristics of metrics that enhance their value for management: (1) they quantify both status and trends through time; (2) they are scalable and can be applied consistently across management levels (from individual reserves to the whole state); (3) most can be mapped, essential for identifying where and when to implement fire management; and (4) their complementarity provides unique insights to guide fire management for ecological outcomes. Conclusions These metrics reflect common relationships between fire and biodiversity and are relevant to management in fire-prone ecosystems worldwide. They facilitate consistent translation of management responsibilities (planning, evaluation, reporting) across administrative levels and enable managers to strategically plan on-ground actions and transparently evaluate outcomes against strategic goals. A key next step for fire managers globally is to define “desirable” states for ecological metrics, to enable target-setting and the evaluation of management outcomes.