Do butterflies use Singapore's nature ways as movement corridors?

Abstract

Habitat loss and fragmentation negatively impact many aspects of biodiversity. Ecological corridors are increasingly adopted to restore habitat connectivity in urban landscapes. Singapore has implemented Nature Ways (NW) to connect its parks and reserves for faunal movement, however, research on their wildlife usage is lacking. This project studied how butterflies use NWs by collecting movement data via mark-release-recapture (MRR). This study investigated the following hypotheses: (1) More naturalistic NWs harbour greater biodiversity; (2) Butterflies move greater distances in more natural NWs; (3) Butterflies move from high-biodiversity source habitats to sink habitats; and (4) Inter-species differences affect movement distances. Two NWs, Admiralty NW (site AP) and Kheam Hock NW (site BG) were selected for study and classified as “Urban” and “Natural” respectively based on site characteristics of land use and vegetation quality. After ten recapture event days at each site, 476 individuals representing 45 species were marked. Site BG had higher measures of biodiversity than AP, though AP had a higher recapture rate. One-tailed binomial tests found no distinct directionality of movements. Based on linear regression models, only site, but not species and life history traits, significantly affected movement distances. Captures and flight paths were concentrated at NW segments that overlapped green habitats, and distributions were affected by roads, habitat edges, and larval host plant presence. This study concludes butterflies use NWs to a limited extent. To improve this, attractive plantings should be extended and diversified along NWs to form continuous habitat that links up green spaces.