M2 Internship – Drivers of Earthworm Biodiversity and Functional Traits in the Threatened Mekong Delta (Vietnam)

Context
The Mekong Delta region is a major hub for ecosystem services delivered through agriculture and therefore plays a critical social and economic role in Vietnam. Soil fauna—particularly earthworms—are key contributors to the region’s high productivity. However, salinization and rising sea levels threaten its long-term sustainability. In this context, understanding the factors that shape the biodiversity and functional traits of keystone species such as earthworms is essential to anticipate future ecosystem dynamics and ensure the continued delivery of vital services.

Objective
Using an available database on earthworm communities, individuals’ traits, and soil properties (including texture, carbon content, pH, salinity, and bulk density) across the entire Vietnamese Mekong Delta, this internship will investigate the factors that drive earthworm taxonomic and functional richness. A separate analysis will be performed to compare native, widespread and invasive species. The resulting models will be applied to map biodiversity, community composition, and functional traits throughout the region, thereby identifying functional hotspots and coldspots.

Tasks
• Model the response of taxonomic and functional traits to the environmental factors, identify the main drivers.
• Build a harmonized database of environmental predictors for the region, using open data, in order to apply the model.
• Map the trends to identify hot and cold spots of biodiversity and functionality
• Identifying zones at high risk of functional loss due to rising sea levels and salinization

Skills
• Solid background in statistics applied to ecology.
• Experience with GIS and spatial analysis (QGIS, R/Python).
• Good written and oral communication skills in English (the project involves communication in English with the Vietnamese team)
• Capable of working autonomously and taking initiative

Location
iEES-Paris, Pierre & Marie Campus, 75005 Paris.

Supervisors
Jérôme Mathieu (Paris), Nicolas Bottinelli (Hanoi), Thibaud Decaens (Montpellier) and Dang Hai Lam (VietNam).

Duration and funding
6 months, starting date flexlible, ideally January – February 2025 (~600 € net/month).

Prospects
The internship can lead to a PhD project on soil biodiversity and ecosystem services in Vietnam (potential funding: ANR projects and/or ministerial PhD grants).

Contacts
jerome.mathieu@sorbonne-universite.fr
nicolas.bottinelli@ird.fr

Application Deadline
Oct. 13th 2025

References of the team
Mathieu, Reynolds, Fragoso, Hadly. 2024, Multiple invasion routes have led to the pervasive introduction of earthworms in North America, Nature Ecology & Evolution (8) 489-499
Wu, Du, Eisenhauer, Mathieu, Chu, 2025, Global engineering effects of soil invertebrates on ecosystem functions, Nature, (640) 120-129
Bottinelli, N., et al. « Why is the influence of soil macrofauna on soil structure only considered by soil ecologists?. » Soil and Tillage Research 146 (2015): 118-124