Short‐term effects of low intensity fire on soil macroinvertebrate assemblages in different vegetation patch types in an Australian tropical savanna

Abstract

Early dry season fires are a common land management regime employed across the tropical savannas of northern Australia. The rationale is that this reduces fuel loads and so reduces fire risk in the latter part of the dry season. Despite the acceptance of fire as a major management tool the ecological effects of fire remain uncertain. Vegetation patches and their associated macroinvertebrates play a critical role in the capture and recycling of water and nutrients. The aim of this study was to examine the responses of soil macroinvertebrates, within different types of vegetation patches, to early dry season fires in tropical savanna woodland in northern Australia. The abundance of major macroinvertebrate taxa and functional groups, and taxon richness were quantified in three vegetation patch types 2 weeks before and 2 weeks after burning. Termites dominated the soil macroinvertebrate assemblage sampled. Fire led to significant decreases in ant and spider abundances and overall taxon richness. Functional group analyses showed significant overall declines in the abundances of macropredators and litter transformers. There were also interactions between fire and patch type; in tree patches, fire significantly reduced total macroinvertebrate abundance, as well as the abundance of termites and ecosystem engineers. These changes in soil macroinvertebrates will potentially influence patch functionality, with important implications for soil processes and landscape health.

Impacts of Prescribed Fire Frequency on Coarse Woody Debris Volume, Decomposition and Termite Activity in the Longleaf Pine Flatwoods of Florida

“…He found termite richness to be slightly higher in the seasonally burned forest but relative abundance data were not collected. In an Australian tropical savanna, Dawes-Gromadzki [45] found termite abundance declined in tree patches following an early dry-season burn. Most recently, Davies et al [16] found termites to be highly resistant to fire in African savannas although tolerance varied considerably among functional groups.…”

Termites and fire: Current understanding and future research directions for improved savanna conservation

“…(1976), Benzie (1986), Ferrar (1982), Desouza et al . (2003), Dawes‐Gromadzki (2007) and Traoré and Lepage (2008). These constitute four from Africa, and one each from South America and Australia.…”

“…1976; Benzie 1986; Traoré & Lepage 2008) and three with single‐fire events (Ferrar 1982; Desouza et al . 2003; Dawes‐Gromadzki 2007). The three studies dealing with fire regimes (all conducted in Africa) considered only two extreme regimes: that of fire exclusion and of annual burns.…”

Termites, vertebrate herbivores, and the fruiting success of Acacia drepanolobium

“…Through their mound-building activities, termites enrich soils, contribute to both large-and small-scale habitat heterogeneity, and provide critical resources to a diverse suite of species on many continents (e.g., West Africa, Konate et al 1999, Ndiaye 2004Australia, Black and Okwakol 1997;Europe, Wolters 2000;andNorth America, Nash andWhitford 1995, Fox 2003). How these potential ''islands of fertility'' (Schlesinger et al 1996, Lavelle et al 1997, Dawes-Gromadzki 2007 created by termite mounds affect measures of plant fitness is largely unknown. In addition, the effects of soil enrichment by termites might be enhanced or diminished by vertebrate herbivores that preferentially graze on mound grasses and deposit nutrients in dung and urine.…”