Exploring Competitive Interactions Between Non-Crop Plants in a Coffee Agroecosystem and the Potential for Coexistence

Agroecosystems integrate ecological principles to balance food production with biodiversity conservation. Despite efforts to use sustainable practices, weeds are still seen as problematic due to common views on plant competition. Plant diversity is crucial for maintaining agrobiodiversity, supporting functions like pollination, soil erosion control, and habitats for beneficial insects, while also contributing to ecosystem stability and multifunctionality. Current literature on plant competition provides insight into how competition influences species composition, thereby structuring communities. By integrating Indigenous agricultural practices with agroecological principles, we can better manage non-crop plants that offer potential benefits. Sustainable management practices based on agroecological principles can support agrobiodiversity and ecosystem function. This study evaluates the effect of interspecific and intraspecific interactions combined with above and below-ground competition between two dominant native weed species (Ipomoea purpurea and Viguiera cordata) in a coffee agroecosystem in the Soconusco region of Chiapas, Mexico. Field experiments with 102 plants across six sites (15mx20m) and four treatments (control, root competition, shoot competition, and root and shoot competition) were conducted over 9 weeks in a 278-hectare organic shaded coffee farm. The findings from this study suggest that in this agroecosystem both intraspecific and interspecific competition are occurring simultaneously with the impact on growth varying across treatments. We find that the additive effects of root and shoot competition significantly reduce the height and number of leaves for both plant species. Promisingly, these findings suggest that competitive interactions between Ipomoea purpura and Viguiera cordata can contribute to their management and coexistence. Understanding plant coexistence can help develop weed management practices that enhance plant diversity, thereby providing ecosystem benefits that support mid-to-long term stability. This study lays the foundation for more extensive research on weed competition within the coffee agroecosystem and provides insights into the natural management of weed communities.