A sunny spot: habitat management through vegetation cuts increases oviposition in abandoned fields in an endemic Mediterranean butterfly

The abandonment of agricultural land and the afforestation of grassland habitats represent major threats for butterflies in European and Mediterranean areas. A crucial goal for Lepidoptera conservation is to maintain and/or restore habitat quality by targeted management. Nevertheless, there are few experimental studies allowing to derive data-driven strategies to protect butterflies of open grasslands in the Mediterranean region. We developed a habitat management strategy for the conservation of the Italian endemic butterfly Zerynthia cassandra by adopting a three-step procedure: (i) characterising which environmental and host plant features influence oviposition on plants; (ii) identifying and testing the effect of a data-driven habitat management intervention; (iii) understanding which micro-habitat features promote Z. cassandra oviposition in restored places to optimise the intervention. Both patch (areas of 1 m radius hosting Aristolochia shoots) and plant features affect oviposition, with the strongest positive effects showed by high irradiation of the patch and plant quality (high number of flowers and leaves). Accordingly, the management consisted in vegetation cuts to increase irradiation, and 2 years of monitoring demonstrated that this procedure significantly increased oviposition (average increase of about 2 eggs per plant) and larval presence. Micro-habitat sampling demonstrated that the maximum oviposition differed between vegetation structures, highlighting the importance of a local fine-tuning before the intervention. We provided a data-driven, effective, and sustainable management strategy to increase habitat suitability and oviposition for an endemic and endangered Mediterranean butterfly. Our framework can drive management strategies for other species with similar ecological requirements and subjected to similar threats.