Diversity and microclimatic patterns of vascular plant communities in cave-associated karst microhabitats of Ngantap Cave, Central Java, Indonesia

Abstract

Abstract. Paramesti H, Sheliana MS, Hapsari M, Hasan MT, Susatio R, Jumari, Suharno, Setiawan AD. 2025. Diversity and microclimatic patterns of vascular plant communities in cave-associated karst microhabitats of Ngantap Cave, Central Java, Indonesia. Intl J Trop Drylands 9: 169-180. Karst ecosystems are characterized by strong environmental heterogeneity driven by limestone geomorphology, shallow soils, and localized microclimatic variation. Within these systems, caves play an important role in shaping surrounding terrestrial habitats by generating gradients in light availability, humidity, and air movement. Despite their ecological significance, vegetation associated with cave-related microhabitats outside the cave interior remains poorly documented in tropical karst regions, including Indonesia. This study examines vascular plant communities associated with cave-related microhabitats around Ngantap Cave, Wonogiri District, Central Java, Indonesia, part of the Gunung Sewu UNESCO Global Geopark. Vegetation sampling was conducted using line transects across three cave-associated microhabitat zones: entrance, cliff, and twilight. A total area of 1,800 m² was surveyed, and all vascular plant individuals were recorded and classified by species, family, growth form, and origin status (native, introduced, cultivated). Microclimatic parameters, including air temperature, relative humidity, light intensity, and wind speed, were measured to characterize environmental gradients among zones. Community structure was analyzed using Shannon–Wiener diversity, Simpson dominance, and Pielou evenness indices within a descriptive–comparative framework. A total of 41 vascular plant species belonging to 22 families and comprising 1,736 individuals were recorded. Herbaceous species and ferns dominated cave-associated assemblages, whereas shrubs and small trees were less frequent, and large canopy trees were absent. Species richness and diversity were highest in the entrance zone and declined toward the twilight zone, which supported only a limited number of shade- and humidity-tolerant taxa. Microclimatic conditions exhibited clear and directional gradients, with increasing relative humidity and decreasing light intensity and air movement from the entrance to the twilight zone. Introduced and cultivated species were present but largely confined to entrance areas, reflecting historical tourism-related activities rather than ongoing biological invasion. These findings demonstrate that cave-associated microhabitats support distinct plant communities structured by fine-scale environmental filtering and provide baseline ecological information essential for conserving microhabitat diversity in tropical karst ecosystems.