Fire regime shifts as a consequence of fire policy and socio-economic development: An analysis based on the change point approach

When fire events remain recurrent in a given area over a certain period of time they usually result in a specific fire regime. Where humans interact with the landscapes, changing their flammability and acting as fire initiators or suppressors, fire regimes may change. Developing an objective and quantitative method for detecting short-term changes in fire regimes could be of paramount importance for addressing the effectiveness of fire management measures. We used the change point approach to detect shifts in fire frequency and extent in a 100-year fire dataset of two Swiss cantons (Ticino and Valais) differing in environmental, socioeconomic and legal context. We then analyzed the detected changes in fire regimes in the light of the implemented fire policy and the socio-economic evolution. Our results show the suitability of the approach for detecting change points. We found in particular that in the less fire-prone Canton of Valais, major driving forces that yield shifts in fire regimes are of climatic and socio-economic origin, whereas in the fire-prone Canton of Ticino fire policy measures also contributed to detectable changes. Fire legislative measures led to reduced fire frequencies, whereas improvements in fire-fighting resulted in a reduction of burnt area. Policy makers may learn from such analyses for planning future measures.

► Objective and quantitative methods for detecting short-term changes in fire regime are not used in current fire research.
► The Pettitt-test applied stepwise or on a moving window is suitable to detect multiple fire regime shifts.
► Fire policy measures (legislation and fire-fighting organization) and the socioeconomic evolution may change fire regimes.