As soil health becomes a defining goal of the EU Soil Strategy for 2030, researchers at Aarhus University are rethinking how we model what lives beneath our feet. Their new spatially explicit population model for the soil invertebrate Folsomia candida (springtails), published in the open-access Agricultural and Environmental Modelling journal, marks a significant step beyond standard laboratory testing.
For over 60 years, traditional ecotoxicological testing has provided valuable baseline data, but these highly controlled laboratory tests often overlook dynamic environmental drivers like fluctuating temperature and soil moisture. To address this critical gap, researchers developed a highly realistic stage-structured population model within the Animal, Landscape and Man Simulation System (ALMaSS) framework.
“This model explicitly represents egg, juvenile, and adult life stages, linking development, reproduction, and survival to environmental conditions using empirically parameterized thermal performance curves,” note the researchers. This approached allowed for a non-linear look at how populations actually respond to their environment.
The newly published formal model integrates these dynamic landscape elements by combining static soil properties with hourly ERA5 weather data, vegetation growth, and daily crop management practices. A key highlight of the tool is its advanced soil moisture tracking, which uses a novel integration of evapotranspiration data and physical soil properties to accurately estimate surface soil water potential. Using daily time steps for simulations lasting up to five years, the model captures subpopulation dynamics at a high-resolution spatial scale of 100 square meters.
Even though the current version of the model focuses purely on environmental stressors without chemical exposure, its flexible structure serves as a foundational framework that can be easily extended. By eventually integrating toxicity modules, the model will enable the investigation of population-level impacts driven by agrochemical usage, such as pesticides and fertilizers, across different European farming practices.
"This mechanistic framework can improve the interpretation of standardised laboratory and higher-tier mesocosm tests, providing a crucial tool for assessing the impact of multiple stressors under environmentally realistic scenarios. Ultimately, models like this offer a pathway towards more scientifically grounded, realistic assessments of ecosystem health in a changing environment," concludes the team.
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