doi:10.3390/su17052195engSalvadó, ZoelNovo, MaiteDealing with urban biodiversity through butterfly gardens: a project-based learning proposal for pre-service teachers trainingART-2025-143403Research in environmental education points out the need for an improvement in pre-service teacher education training in this area. This proposal follows PBL methodology and focuses on the development of an environmental education project whose final product is the organization of a science fair for elementary school students. The 5-week project addresses the topic of urban biodiversity decline and uses the butterfly garden as an initiative to mitigate it. Four months after the program ended, a survey was administered to the 86 participating pre-service teachers. A mixed-methods approach was used, collecting quantitative data on perceptions of urban biodiversity decline, the One Health concept, and environmental education, along with qualitative keyword responses to open-ended questions about the butterfly garden’s impact and the project’s value for self-learning and professional development. Participants reported positive perceptions regarding butterfly gardens after participating in our environmental program, recognizing them as both a valuable educational resource and an effective initiative to mitigate urban biodiversity decline. Respondents showed a strong pro-environmental attitude, taking seriously their role in transmitting environmental values. Using a butterfly garden for teaching purposes offers insight into environmental literacy, connection with nature, and improvements in well-being and is a powerful platform for deep and meaningful pedagogical learning.2025http://zaguan.unizar.es/record/15203210.3390/su17052195http://zaguan.unizar.es/record/152032oai:zaguan.unizar.es:152032info:eu-repo/grantAgreement/ES/DGA-FEDER/S27-23RSustainability (Switzerland) 17, 5 (2025), 2195 [22 pp.]byhttps://creativecommons.org/licenses/by/4.0/deed.esinfo:eu-repo/semantics/openAccess