Butterflies (Lepidoptera: Papilionoidea) of the Southern Bolkar Mountains and Adjacent Çukurova Plain (Mersin, Türkiye): Richness and Turnover Along a 2–2200 m Elevational Gradient

Abstract

The southern slopes of the Bolkar Mountains, in the western Bolkar massif of the central Taurus range, compress the full sequence of eastern Mediterranean vegetation zones into a short horizontal distance, yet their butterfly fauna has never been surveyed as a continuous gradient. Here the butterflies (Lepidoptera: Papilionoidea) of a 2–2200 m transect in Mersin Province, southern Türkiye, are documented, extending from the coastal Çukurova plain to the subalpine belt. Seventy-one sampling events were carried out on 58 dates between 2016 and 2024 in the districts of Toroslar, Çamlıyayla, Tarsus and Akdeniz. A total of 143 species in 70 genera, 16 subfamilies and five families were recorded, based on 832 specimens-by-locality records. Lycaenidae was the most species-rich family (55 species, 38.46%), followed by Nymphalidae (44, 30.77%), Pieridae and Hesperiidae (19 each, 13.29%) and Papilionidae (6, 4.20%). Sample coverage reached 96.7% and observed richness corresponded to 90.6% of the Chao2 estimate of 157.9 species. Richness increased with elevation and remained significant after adjustment for month of sampling (negative-binomial GLM, β = +0.303, p < 0.001); rarefied to equal effort, richness rose from 21.8 species in the 2–400 m belt to 92.0 in the 1501–2200 m belt. Assemblage composition differed strongly among belts (PERMANOVA, F = 4.66, p < 0.001), and beta diversity was dominated by turnover (88.8% of total Sørensen dissimilarity) rather than nestedness. Thirteen sampling events fell within Wildlife Development Areas; these were no richer than unprotected localities at comparable elevations, but less completely surveyed (sample coverage 75.5% against 96.2%). Comparison with the records compiled for the same area by Hesselbarth and co-workers, which list 126 species, showed 104 species in common; 39 species are added here and 22 historical records were not refound, giving 165 species now known from the gradient. The results identify the entire elevational sequence, rather than any single belt, as the unit of conservation interest, and the interior of the existing reserves as the most immediate survey priority.