Using Fire History Data to Map Temporal Sequences of Fire Return Intervals and Seasons

[摘要] Analysis of complex spatio-temporal fire data is an important tool to assist the management and study of fire regimes. For fire ecologists, a useful visual aid to identify contrasting fire regimes is to map temporal sequences of data such as fire return intervals, seasons, and types (planned versus unplanned fire) across the landscape. However, most of the programs that map this information are costly and complex, requiring specialist training. We present a simple yet novel method for creating sequences of temporal data for mapping fire regimes using basic geographic information system (GIS) techniques and logical test functions in Microsoft® Excel 2003 (Microsoft, Bellevue, Washington, USA). Using fire history data (1972 to 2005) for southwestern Australia, we assigned integer classifications to fire return intervals (short, moderate, and long) and fire types and seasons (wildfires and prescribed burns in different seasons) and joined the integer classifications together to form a sequence of numbers representing the order of either fire return intervals or fire seasons in reverse time sequence. This sequence can be mapped in a GIS environment so that spatial dimensions formed by overlapping polygons are readily observed, and the temporal sequence of fire data within each polygon can be interpreted across the landscape. We applied the technique to examine experimental design options for investigating the effects of contrasting fire regimes on biota at the landscape scale. This investigation identified several important factors: 1) patterns were evident in fire types and seasons, 2) patterns were evident for fire return interval sequences, and 3) combining fire types and seasons with fire return intervals significantly constrained options for the study design. A visual analysis of this type highlights fire regime patterns in the landscape and permits a feasibility study for the development of study design options and the spatial arrangement of potential study sites.

[学科分类] 生态、进化、行为和系统

[关键词] fire history data;fire management;fire regimes;fire return interval sequences;fire season sequences;Geographic Information Systems;prescribed burning;southwest Western Australia;spatio-temporal analysis;wildfires