Relationships among fire frequency, rainfall and vegetation patterns in the wet–dry tropics of northern Australia: an analysis based on NOAA‐AVHRR data

摘要: Aim  To quantify the regional-scale spatio-temporal relationships among rainfall, vegetation and fire frequency in Australian wet–dry tropics (AWDT). Location  Northern Australia: Cape York Peninsula, central Arnhem, Kimberly, Einasleigh Uplands, Gulf Fall Uplands northern Kimberley. Methods  Monthly ‘fraction of photosynthetic active radiation absorbed by green vegetation’ (fAPAR) was decomposed into monthly evergreen (EG) raingreen (RG) components using time-series techniques applied to normalized difference index (NDVI) data from Advanced Very High Resolution Radiometer (AVHRR) imagery. Fire affected areas were independently mapped at same resolution AVHRR Weather station records spatially interpolated create rainfall surfaces. Vegetation structural classes derived a digitized map communities (1 : 1,000,000). Generalized linear models used fAPAR, EG RG signals, structure, frequency, for period November 1996–December 2001. Results  The fAPAR signals are positively correlated with annual canopy cover, notably: EGclosed forest > EGopen heathland > EGopen forest > EGwoodland > EGopen woodland > EGlow open woodland > EGopen grassland. height correlated, excluding special case heathland. signal is highest where intermediate strong seasonality coincide, associated structure as follows: RGopen grassland > RGwoodland > RGopen forest > RGopen heathland > RGlow woodland > RGopen woodland > RGlow woodland > RGclosed forest. tracks rainfall. Annual proportion area burnt (PB) maximal high coincides low (open grassland, several communities). PB minimal both (low woodland); (closed forest, heathland). Conclusions  RG–EG scheme successfully reflects digitally tree grass covers relation patterns strongly patterns. RG, biomass production during wet season supports abundant fine fuel dry season. EG, relatively moist limits ignition; relative short supply spread.