Abundance and diversity of termites in a savanna woodland reserve in tropical Australia

Abstract

This study contributes to the paucity of knowledge on the structure of Australian tropical savanna termite assemblages, compared with that available for tropical savannas elsewhere in the world. Termite species diversity, frequency of occurrence and functional diversity in Charles Darwin National Park, a savanna woodland reserve in tropical northern Australia, were assessed. In four 50 ¥ 50 m sites, a direct search and bait sampling protocol was used to sample mounds, standing and lying dead wood, litter, soil and arboreal nest microhabitats for termites between April and June 2003. Results were compared with a priori predictions of termite community structure based on the work by Braithwaite et al. (1988). Sixteen species from nine genera and three families (Mastotermitidae, Rhinotermitidae and Termitidae) were recorded, including the first record of Ephelotermes taylori (Hill) from open savanna woodland habitat and the first official record of Macrognathotermes errator Miller from north Australian savanna. The family Termitidae represented 69% of termite occurrences. From this family, the wood/soil interface feeder Nasutitermes eucalypti (Mjöberg) represented 30% of encounters. High levels of termite activity were recorded at baits within 6 weeks. Four nesting habits were represented: epigeal (mounds above ground), hypogeal (subterranean nests), nests within wood and arboreal nests. Termites were most frequently encountered in epigeal mounds and lying dead wood. Wood and wood/soil interface feeders were the most common. The findings partially supported the a priori predictions proposed. The termite assemblage structure was represented by species commonly found in other Northern Territory savanna woodland habitats. However, species diversity was lower; soil feeders and live wood feeders were less common and grass-harvesting species were absent. Soil nitrogen and phosphorus and species richness and patchiness of ground vegetation may contribute to these differences. The lower species diversity recorded contrasts with the richer termite faunas of tropical savannas recorded elsewhere.

N<sub>2</sub>O, NO, N<sub>2</sub> and CO<sub>2</sub> emissions from tropical savanna and grassland of northern Australia: an incubation experiment with intact soil cores

“…For total site exchange, it has to be noted that termite mounds have been identified as hotspots of N 2 O emissions in savannas (e.g., Brümmer et al, 2009b) and are abundant in savannas of tropical Australia (Dawes-Gromadzki, 2008), but the total contribution to the soil-atmosphere exchange is highly variable in space. It was also reported that belowground termite activity can (often only temporarily) add to on-site variability of measured in situ fluxes (Livesley et al, 2011).…”

Assessing the Relative Efficiency of Termite Sampling Methods along a Rainfall Gradient in African Savannas

“…Active searching transects, on the other hand, sample all termites, but are labour intensive and often less effective for hard savanna soils (although see e.g. , Dawes-Gromadzki 2005, 2008.…”

Termite assemblage structure on Grazing lands in Semi-arid Nakasongola

“…Once the species are deprived of sufficient amounts of litter or when the density of termite mounds is high, they resort to standing biomass and can consume more than 60% of the standing crop. In the current study, specialized grass feeders such as Trinervitermes oeconomus were very rare and this could be attributed to the low plant richness of the ground layer and the general patchiness of ground vegetation (Dawes-Gromadzki, 2008). Further, the deterioration of rangeland ecosystem attributable to overgrazing and indiscriminate tree cutting could have derived members of the sub-family Macrotermitinae of adequate litter for nourishment which in turn resorted to grass for survival.…”

“…Epigeal-nesting species were the most common species followed by hypogeal-nesting species and this was attributed to the high termite encounter rates in mounds and lying dead wood. Dawes-Gromadzki (2008) also noted that epigeal nesting species were the most abundant species accounting for 88% of the total species in Savanna woodland reserve in Tropical Australia. Wood-nesting species were also represented but arboreal-nesting species were very rare.…”

“…different feeding habits) is critical (Dawes-Gromadzki, 2008). It is a prerequisite for evaluating and quantifying the type and extent of their functional roles in ecosystem processes, i.e.…”