COLONISATION OF REHABILITATED LANDS BY TERMITES (DICTYOPTERA), RTA GOVE BAUXITE MINE, NT, AUSTRALIA

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1 COLONISATION OF REHABILITATED LANDS BY TERMITES (DICTYOPTERA), RTA GOVE BAUXITE MINE, NT, AUSTRALIA 1, 3 Alister Spain, 2 Dieter Hinz, 3 Mark Tibbett, 1 School of Earth Sciences, James Cook University, Queensland 2 Crows Nest, Queensland 3 Centre for Land Rehabilitation, The University of Western Australia, Western Australia

2 INTRODUCTION Termites: social insects important to ecosystem and soil development processes. Termites may also have negative effects on mining infrastructure and post-mining rehabilitation works Termites have a winged stage in life cycle, and potentially can rapidly colonise sites rehabilitated post-mining, although effects difficult to observe Common throughout the tropics/subtropics, decline in diversity and in their effects on ecosystems with increasing latitude and elevation

3 INTRODUCTION (cont.) - Ecological strategies Effects largely determined by WHAT THEY EAT and WHERE THEY FEED AND NEST: GRASS/LITTER FEEDERS: feed on surface grass, grassy litter, incl. dung WOOD FEEDERS: feed on woody materials, including transported wood, litter and standing dead and living trees SOIL-WOOD FEEDERS: feed on highly decomposed wood at the interface of soil and sounder wood SOIL FEEDERS: feed on humified materials POLYPHAGOUS SPECIES: Species feeding on a wide range of undecomposed and partly-decomposed woody materials, including living plants

4 INTRODUCTION (cont.) This presentation aims: 1. To present patterns of termite colonisation of a 26- year chronosequence (age series) of mined areas rehabilitated to native forest, RTA Gove bauxite mine, Australia; 2. To link termite colonisation to the changing resource presence that occurs with ecosystem development; and 3. To indicate, in a preliminary way, some trends in their effects on soils.

5 Location of the RTA Gove bauxite mine E RTA Gove RTA bauxite Gove mine bauxite mine S Cape York Peninsula Cairns Gulf of Carpentaria

6 Selected environmental characteristics of the RTA Gove mine site Soil classification: Oxisol (Soil Taxonomy), Kandosol (Austr. soil class.) Native forest community structure: Tall open forest /savanna Rainfall: 1444 mm y -1, most Nov. to April

7 Mining-rehabilitation processes Standard strip mining-rehabilitation sequence of procedures (this conference series, 2006; Tibbett, 2010) Plant species established by seeding late in dry season Rehabilitated areas protected from firing Successfully-rehabilitated areas go through a series of overlapping stages

8 Land prepared for seeding (right) and early establishment phase (<1-yr-rehab. Site, left)

9 Early development stage (a): rehabilitated 5 years

10 Early development stage: mounds of litterfeeding termite Amitermes vitiosus in a site rehabilitated for 7 years, die out around canopy closure

11 Woodland development stage: rehabilitated for 13 years

12 Early maturity: 20-yearrehabilitated site

13 Early maturity: 26-year-rehab. forest site dominated by Eucalyptus tetrodonta

14 Native forest site: Mound built by Coptotermes acinaciformis, a specialist in eucalypt wood: not found in rehabilitated environments

15 Examination of: STUDY METHODS Transported wood, living and dead trees, shrubs, grasses soil surface, under stones and logs and the upper few cm of the profile Censuses of the mounds of mound-building species Baiting - paper baits

16 Attacks on paper baits: paired sites in the 26 year chronosequence and in four native forest sites, 66 days exposure (n = 10) (2001) 4 3 Mean score for 4 native forest sites Rehabilitation period (y) Baits_rhb_26yb.mgf

17 RTA Gove mine: major termite groups colonising rehabilitated environments DEVELOPMENTAL STAGES Plant community A. laurensis A. vitiosus Tumulitermes sp. Heterotermes spp. Schedorhinotermes spp. Microcerotermes spp. N. graveolus Snapping mandibles group M. darwiniensis N. longipennis Establishment development Early Closure Woodland development GRASS LITTER FEEDERS DECOMPOSING WOOD FEEDERS POLYPHAGOUS SPECIES REHABILITATION PERIOD (y) Early maturation Term_gps_26yb_ppt.mgf

18 Ecosystem development: termite feeding resources, galleries and other constructs DEVELOPMENT STAGES Plant community Transported wood Grass-dominated litter Woody litter Short-lived species Long-lived species Active in woody litter Soil galleries ubiquitous Epigeal mounds Runways on stems Sheeting on stems Establishment development Early Closure Woodland development FEEDING RESOURCES TERMITE GALLERIES/CONSTRUCTS REHABILITATION PERIOD (y) Early maturation Constructs_rhb_sites_d.mgf

19 Conclusions Initial termite colonisation of rehabilitated sites occurs in wood and soils transported onto the site during soil profile reconstruction, thereafter by natural dispersal mechanisms Termite establishment/survival depends on the presence of appropriate feeding and other resources and environmental conditions : Some litter-feeding species colonise early but disappear by the time of canopy closure Generalised wood-feeding species are the most common termites colonising rehabilitated areas and are highly active from the third year after seeding

20 Conclusions (continued) Species with specific habitat requirements and the specialised wood-feeding and humus-feeding species are unlikely to succeed in the rehabilitated areas until appropriate resources become available Potential pest termites (e.g., Mastotermes darwiniensis) are unlikely to pose problems unless plants are stressed (e.g., fire, drought, salinity, etc.) or feeding resources are provided for the termites (e.g., excess woody mulch) It is concluded that, as in other environments, termites play important and positive roles in ecosystem and soil development in environments rehabilitated post-mining

21 END