Abstract. Kurniawan ID, Rahmadi C, Akbar RTM, Prakarsa TBP. 2022. Stygobiotic isopod Stenasellus sp. in Sarongge Jompong cave, Tasikmalaya karst area, Indonesia. Biodiversitas 23: 1495-1504. Stenasellus, a stygobiotic isopod, was first reported in Tasikmalaya karst by local cavers in 2018 in Sarongge Jompong Cave. This study aimed to investigate the population, activities, and habitat characteristics of Stenasellus sp. in Sarongge Jompong, Tasikmalaya karst area, Indonesia. Population and activities were recorded through direct intuitive search. We measured several important physicochemical parameters to study habitat characteristics. Statistical analyses-namely Non-metric Multi-dimensional Scaling and Detrended Correspondence Analysis-were conducted to understand the difference in water characteristics among microhabitats and the relation between water characteristics and population size. The results showed that the population was distributed in 4 microhabitats with the maximum observed individuals of 8. Several activities were successfully monitored, including crawling, resting, hiding in crevices, and moving to different locations through the water. All microhabitats were wet gours connected to small water currents located in the dark zone of the cave passage. Water characteristics of microhabitat site 1 were more similar to site 2 and the numbers of individuals in these sites were larger than sites 3 and 4. Among water parameters, resistivity showed the most robust relation with Stenasellus population in which both variables were positively correlated. This correlation indicated that Stenasellus sp. preferred microhabitats with less contamination. Intrinsic and extrinsic factors may potentially threaten the population. The potential threats and conservation challenges need to be identified and mitigated to reduce the risk of biodiversity loss to these isopods, mainly due to their small population size, specific microhabitat, and susceptibility to disturbance. Considering these factors, research on taxonomy will be essential for conservation efforts.

Cave crickets are considered as a keystone species that can be used as a cave ecosystem bioindicator. Developing caves as tourism has considerable potential to disturb cave cricket populations. This study aimed to investigate cave cricket population structure and their habitat preference in Sanghyang Kenit cave one year after it developed into a show cave. Data were collected through standardized visual searching in three cave zones: entrance, twilight, and dark. Besides cave crickets, other macroarthropods discovered in each zone were also recorded. Abiotic parameters of habitat comprised air and soil temperatures, RH, soil moisture, soil pH, and light intensity were measured. Data were analyzed to show cave crickets abundance, density, sex ratio, and age structure. Statistical analysis comprising Kruskal Wallis, non-metric multidimensional scaling, and correlation tests were performed. The cave cricket population in Sanghyang Kenit belonged to a single species, Rhaphidophora sp. The population was around 78-108 individuals and distributed in all cave zones. The abundance and density in twilight and dark zones were significantly higher than in the entrance. The number of males outperformed females with a 2.16 ratio. Besides, the population was dominated by the sub-adult class. Environmental parameters of twilight and dark zones tended to be similar to one another compared to the entrance. Cave crickets preferred habitats with dark, humid, and acidic soil pH. Heteropoda sp. and Catagaeus sp. were considered potential predators. This study implies the importance of protecting cave crickets in Sanghyang Kenit.