行政院國家科學委員會補助專題研究計畫成果報告

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1 () NSC

2 () Cave biodiversity and conservation in Kenting, Taiwan. NSC and undisturbed caves at Kenting National Park, Taiwan was studied between August 2000 and July The diversity of species and number of animals was lower in disturbed caves Invertebrates such as the crickets (Ceuthophilus maculatus), spiders (Heteropoda venatoria), and bats (Himalayan leaf-nosed bat Hipposideros armiger terasensis, Horseshoe bat (Ceuthophilus maculatus) Rhinolophus monoceros, Woolly (Heteropoda venatoria) horseshoe bat R. luctus formosae and common bent-winged bat Miniopterus Hipposideros armiger terasensis, schreibersii) were recorded in addition Rhinlophus monoceros, R. to snakes, frogs and other invertebrates. luctus formosae Miniopterus There were significantly fewer schreibersii Ceuthophilus maculatus (p<0.001); Heteropoda venatoria (p <0.05) and bats (p<0.05) (p <0.005) in disturbed caves when compared to undisturbed caves. Predator-prey interactions were observed only in undisturbed caves since artificial lights and visitors' disturbance might have limited such natural interactions. Priorities should be given to protect the delicate limestone caves and their fauna in southern Taiwan. ( Abstract) The diversity of vertebrate and invertebrate fauna in human-disturbed Keywords: Limestone caves, invertebrate, vertebrate, conservation, Kenting. 1

3 Caves have been a mysterious world from prehistoric times to the present and the mystery of darkness beyond the entrance always attracted curiosity. Cave habitats often are known to harbor diverse and unique fauna that form heterogeneous assemblies and live in various ecological zones [1, 2]. Cave ecosystems around the world are at risk due to human exploitation and habitat destruction. It is important to collect data on the status of tropical caves and cave environments in order to effectively plan future conservation and management strategies [3]. Little is known about the diversity of fauna in limestone caves of Taiwan. In this paper, we report for the first time quantitative data on the diversity, distribution and abundance of invertebrate and vertebrate fauna in caves of southern Taiwan. Data on faunal diversity are compared between disturbed and undisturbed caves to determine the human impact and recommendations are given to conserve the delicate cave ecosystems in Taiwan. The temperature in the dark zone of caves fluctuated between 22 o C and 25 o C whereas, the relative humidity in the dark zone was higher when compare to outside, entrance, twilight and dark zone of caves. The diversity of animals in undisturbed caves was higher compared to disturbed caves. There were significantly fewer Ceuthophilus maculatus (p< 0.001); Heteropoda venatoria (p<0.05) and bat species (p<0.005) in disturbed caves compared to undisturbed ones. The total number of Ceuthophilus maculatus in disturbed caves was less than 10 and the number of Heteropoda venatori was less than 5, while undisturbed caves had , and individuals, respectively. The total number of Polyrhachis sp. was estimated as 249, 95, 234, 986 and 688 in caves 1, 2, 4, 5 and 6 respectively. They were absent in cave 3. Furthermore, one Taiwan beauty snake (Elaphe taeniura friesei) and two turtle-designed snakes (Trimeresurus mucrosquamatus) were recorded at the entrance and dark zones of cave 6. Bat species such as the Himalayan leaf-nosed bat (Hipposideros armiger terasensis), Horseshoe bat (Rhinolophus monoceros), Woolly horseshoe bat (R. luctus formosae) and Common bent-winged bat (Miniopterus schreibersii) constituted as the major mammalian group found mostly in dark zones of caves. We did not see any bats in disturbed caves with one exception (cave 1) that had a small colony of H. a terasensis (n=43) well hidden away from the tourist trail on the roof of a branch tunnel. Two species of bats, Rhinolophus monoceros (n=500) and R. l. formosae (n=20), were recorded from undisturbed cave 4 while caves 5 and 6 had a colony of H. a.terasensis (n=50) and Miniopterus schreibersii (n=1000), respectively. Spiders (Heteropoda venatoria) were observed to feed on crickets (n=4) and cannibalistic feeding in spiders was observed twice. In cave 4, a small water reservoir was seen in the dark zone. A crab (Geothelphusa albogilva ) was observed to feed on shrimps (Caridina faciata). Frogs such as Rana adenopleura and Microhyla inornata were recorded only from cave 5. Spiders feed on other arthropods as well as their conspecifics. Crabs are often found to be 2

4 predatory on shrimps and other aquatic arthropods. These entomophagous animals in caves are secondary consumers in the food chain. Snakes occasionally feed on bats (Hsu, unpublished data) and they are known to be the top potential consumer in cave ecosystem. We observed predator-prey interactions only in undisturbed caves during our study since artificial light and visitors' disturbance might have limited such interactions in caves used that were frequently used by tourists. The diversity of species was low in caves frequently used by tourists compared to undisturbed caves. Discarded plastics containers, polythene bags, metal cans and other metal trash were seen in undisturbed caves, an indication of infrequent human visits but it apparently did not affect the diversity of species. Artificial lighting system in caves have been reported to contributes heat to the ecosystem and when the energy release exceeds the energy budget of the cave, the inside temperature would increase and reach stationary values higher than natural ones [4]. Bats usually prefer the dark zones of caves to roost. The changes in temperature, humidity, and CO 2 concentration as a result of disturbances by tourists have a documented role in leading to the decline of bat populations in most show caves around the world. It is essential that caves in Taiwan must be managed so that there is reduced contact between people and bats, especially during sensitive breeding periods. Appropriate security gating could be established in caves not only around Kenting but also in other parts of the country to protect the bat populations from human disturbances. Cave animals are particularly vulnerable to disturbances since they live within discrete habitats in isolated island like distributions [3]. It is vital for Taiwan to have legislation specifically to protect caves, similar to the United States [5]. or other countries in Europe. Kenting harbors several caves, which were formed as dripping underground waters minutely shifting calcium carbonate deposits over the millennia. Several of the caves are located closer to farms where farmers periodically expand their agricultural fields often resulting in the closure of caves. In a recent survey, Hsu [6] found seven caves around Kenting fully buried by farmers to expand their fields that could have wiped out all animals. The national park is heavily used for tourism and an estimated three million people visit the park annually. It is important that tourism need to be managed in such a way that ensures the preservation of caves and conservation of cave fauna. Steps must be taken to restore the caves buried by soil, to decelerate the expansion of encroachment by local villagers, to pass legislation specifically to conserve cave environment, and to increase public awareness to protect the delicate cave ecosystems from further destruction. Furthermore, toxic chemicals are sometimes dumped in rivers and landfills across Taiwan [7], which might pollute the underground water systems in caves. Further studies therefore must focus on the impact of toxic chemical pollutants in delicate cave environments in Taiwan. 3

5 [6] Hsu, J. M Population status and conservation of bats (Chiroptera) in Kenting National Park, Taiwan. Oryx, 31: [7] Agoramoorthy, G., and M. J. Hsu Taiwan pays the price for growth, in toxic pollution. Nature, 408: 905. [1] Hubbard, D. A. and D. Wang A preliminary report on some invertebrate cave fauna in China. Proceedings of the 12 th International Congress of Speleology, Switzerland, 3: [2] Andreev, S. P., A. G. Vasiliev, and M. N. Lozan Vertebrate fauna of the Moldavian underground. Proceedings of the 12 th International Congress of Speleology, Switzerland, 3: [3] Slaney, D. P., and P. Weinstein Conservation of cave fauna: more than just bats. Memories of Museum Victoria, 56: [4] Stelcl, O Impact of tourism on the natural environment of the caves open to public in the Moravian karst. Studia Carsologica 3: [5] Huppert, G.N Caves as unique conservation education resources. pp In: D. O'Halloran, C. Green, M. Harley, M. Stanley, and J. Knill (Eds.), Geological and landscape conservation, Geological Society Press, London. 4