Terrestrial Fauna and Flora Inventory Research at Dongsha Island

Project Duration	2005-12-31 ~ 2006-12-30
Research Title	Terrestrial Fauna and Flora Inventory Research at Dongsha Island
Contracted Organization	Taiwan Stream Environment Association
Principal Investigator	Lee Pei-Fen
Co-Principal Investigator	Hsieh Chang-Fu
Project Personnel	Wu Shu-Ping, Lien Yu-Yi, Ko Chih-Jen, Fan Su-Wei, Cheng Yu-Ting, Wu Kuei-Ching, Nie Chia-Hui, Li Yu-Chi
Keywords	Geographic Information System (GIS), mollusks, crustaceans, invasive species, conservation monitoring
Abstract	1. Background: The purpose of this project was to supplement terrestrial ecological survey data for Dongsha Island through field investigations. By establishing an aerial and satellite remote sensing image database and integrating previous spatial ecological survey data using a Geographic Information System (GIS), a terrestrial natural resources and ecological database for Dongsha Atoll National Park was developed. Based on this foundation, recommendations for a conservation monitoring system were proposed to support future terrestrial ecological planning and management. 2. Methods: ESRI ArcGIS was used as the primary database platform. A 1994 aerial photograph served as the base map, overlaid with a 60 m × 60 m grid system to map the distribution of animals, plants, and invasive plant species. Field investigations mainly employed transect surveys supplemented by trapping methods. All survey data with spatial coordinates, including both newly collected and previously compiled data, were digitized and archived using GIS. 3. Major Findings: A total of 170 vascular plant species belonging to 58 families and 144 genera were recorded, including 99 native species, 48 cultivated species, and 23 naturalized species, with 41 newly recorded plant species. Bird surveys documented 140 species from 35 families, including 12 species newly recorded for the area. Terrestrial crustaceans included 10 species in 3 families of large crustaceans, with several newly recorded species; the land hermit crab was confirmed as Coenobita rugosus. Terrestrial mollusks included 26 species in 13 families, of which 20 species (from 4 families) were newly recorded; most species were observed as live individuals and juveniles, and five previously misidentified species were taxonomically corrected. Insects comprised 51 species in 31 families across 9 orders, including 14 newly recorded species. 4. Recommendations: For conservation monitoring, the study recommends using vegetation composition, invasive species, endemic species, birds, mammals, crustaceans, mollusks, insects, invasive plants, land cover, and land use as indicator factors. Standardized survey protocols should be implemented, with detailed records of survey dates, weather conditions, species names, coordinates, habitat descriptions, and sampling routes to facilitate long-term trend analysis. Biosecurity Measures for Invasive Species: 1. Open garbage burial sites are likely major food sources sustaining feral dogs, cats, and rodents. These sites should be isolated to reduce wildlife–human contact. 2. Controlling rodents by raising cats is not recommended, as cats may harm non-target species. Feral dogs and cats should instead be trapped and removed. 3. Poison baits for rodent control may harm non-target species and alternative control methods are advised. 4. Leucaena leucocephala and Bidens pilosa show strong regeneration and reduce biodiversity; minimizing disturbance of native shrublands may help slow their spread. 5. Casuarina equisetifolia occurs beyond camp areas and shows signs of expansion; monitoring is recommended. 6. Periodic monitoring of Casuarina and Leucaena distributions should combine aerial imagery interpretation with ground surveys to track dynamic changes.