Identifying key demographic drivers of a protected butterfly to inform conservation in natural and anthropogenic landscapes

Abstract Butterflies are widely used as indicators of environmental change. Despite this, for many strictly protected species, demographic drivers across life stages are poorly understood, hampering an effective evaluation of their conservation status and trends, especially in anthropogenic landscapes. We investigated the environmental factors shaping the demography of the Italian festoon Zerynthia cassandra (Geyer, [1828]), a strictly protected and host-plant-specialist butterfly endemic to Italy. During spring 2024 and 2025, we monitored adult abundance, oviposition, larval occurrence, host plant availability, nectar resources, habitat structure, disturbance, and landscape context along an ecological gradient across natural, semi-natural, and anthropogenic landscapes in central Italy. We observed that adult abundance was positively associated with nectar availability and host plant abundance, whereas reproductive indicators were primarily driven by host plant availability and disturbance intensity at different scales. Rooting activity by wild boars ( Sus scrofa Linnaeus, 1758) showed consistent positive effects on adult abundance, larval numbers, and apparent egg survival, suggesting that moderate soil disturbance may enhance habitat suitability for this species. Habitat type influenced adult abundance and host plant occupation rates, with open and margin habitats outperforming woodland interiors. In contrast, landscape class (urban vs. natural) and patch size had no significant effects on demographic indicators, indicating that small habitat patches can support viable populations even within heavily modified landscapes. We suggest that adult presence alone is an unreliable proxy for habitat quality, and we highlight the importance of integrating reproductive and early survival metrics into monitoring programmes. Resource availability, habitat structure, and intermediate disturbance jointly determined population performance in Z. cassandra , offering potential suggestions for adaptive conservation and management under the Habitats Directive also in human-dominated landscapes.