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Research Seminar Systems Science

Winter semester 2023/24

Timetable

Abstracts of selected talks

24 October, 2023

Bo-Moon Kim, Centre for Ecological Research, Kyoto University (Japan)

Resource allocation in tragedy of the commons game in plants for belowground competition

The tragedy of the commons (TOC) has been well known since it was proposed and has been widely applied not only to human society but also to many taxa. An increasing number of studies have focused on TOC in belowground competition in plants. In the presence of neighbors, plants overproduce roots to acquire more nutrients than their competitors, resulting in a reduction in reproductive yield. Game theoretic studies on TOC in plants usually consider the amount of root biomass as a strategy and do not consider the growth of plants. However, root volume is considered an outcome of the decision making of plants on whether they allocate more resources to the root. In this study, we incorporated resource allocation and growth dynamics into the TOC game in plants and explored the evolutionarily stable resource allocation strategy in the presence of neighbors. We demonstrated that TOC generally occurs when fitness per individual is always reduced because of the competitive response. However, the overproliferation of roots, which is emphasized as an indicator of TOC, did not necessarily occur, or was sometimes difficult to detect when fitness is largely or completely determined by root biomass. This result suggests the importance of careful observation for examining whether plant species engage in a TOC game.

14 November, 2023

Yue Geng (Agro-Environmental Protection Institute, Ministry of Agriculture, China)

Residual characteristics and ecological risk assessment of typical pesticides and POPs in China: case studies

To date, about 600 pesticides have been registered and used in China; some of these chemicals could accumulate in the soil and potentially leach into groundwater and migrate to surface water. Compared to other pesticides, some may pose a higher risk due to greater persistence in the environment, higher application rates and more adverse ecotoxicological properties. Their risks to environmental safety from accumulation in soil and movement to groundwater and surface water remain unclear. Monitoring data and model predicted concentrations can be used to assess exposure to pesticides on farmland in China. The current study investigated the presence of commonly used pesticides in soil, groundwater and surface water of farmlands from the major agricultural zones of China in a year-round monitoring programme. In addition, fate models were used as effective screening tools to estimate the soil exposure, leaching potential and aquatic exposure of agrochemicals in farmlands of China with a wide range of target crops, climate, topography, soil type and agricultural practices. The corresponding environmental risks were assessed using a risk quotient approach for non-target organisms, including earthworms and aquatic organisms, and for human health through consumption of pesticide-contaminated groundwater. The consistency between monitoring results and modelling results was investigated. In addition, the occurrence of typical OCPs and BDEs in soil was investigated in typical farmland and an electronic waste disposal site in China, and the bioavailability of 2,2',4,4'-tetrabromodiphenyl in soil and its accumulation in green radish and ryegrass were estimated.

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