Termite bioturbation in Cambodia - from characterization to application

2022

Diplôme

Muon R.

Paris (FRA) ; Phnom Penh : Sorbonne Université ; Institut de Technologie du Cambodge, 2022, 126 p. multigr.

Th. Sci. de l'Environ., Sorbonne Université ; Institut de Technologie du Cambodge. 2022/12/15.

Soil biodiversity plays a key role in regulating key ecological functions and in providing essential ecosystem goods and services to human societies. Among soil organisms, termites play a prominent role in tropical soils, as elements of the food web and as ecosystem engineers with effects on soil dynamics and biodiversity at different spatial and temporal scales. Although termite mounds are conspicuous features of the landscapes in the lower Mekong basin, their abundance, properties and utilization by farmers remain unknown. Thus, the aim of this study was to analyze the interactions between termite constructions and farmers in cultivated areas in this region. To this end, we assessed the abundance and properties of two termite constructions (lenticular mounds and mound nests) in paddy fields in Chrey Bak catchment in Cambodia. We showed that termite lenticular mound density reaches ~ 2 mounds ha-1, and that these constructions are likely to find their origin in the building activity of Macrotermes gilvus. We evidenced that termite lenticular mounds and nests can be seen as fertility and biogeochemical hotspots in the landscapes with higher carbon and nutrients contents, and improved soil physical properties (higher clay content, water holding capacity and saturated hydraulic conductivity). Finally, using interviews realized in 13 villages, we showed that termite mounds provide a large number of services to local people, being part of the cultivation practices and contributing to food diversity and health (e.g., utilization of mound soil as amendment, access to medical plants, and lower use of chemical fertilizers and pesticides). To conclude, this interdisciplinary research evidenced the urgent need for a better understanding of the environmental and social impacts of biodiversity, and especially termite activity, and on the driving factors controlling their preservation by farmers.

Constituants et propriétés des sols [068PROSOL] ; Macrofaune [074FAUSOL03] ; Ecosystèmes [082ECOSYS] ; Agriculture, système de production, machinisme agricole [098AGRIC] ; Traitement photographique / Photointerprétation [126TELTRP]

Fonds IRD [F A010092492]

fdi:010092492