Molluscan fauna of Gueishan Island of Taiwan

Study Extent

We conducted literature survey and field investigation for Mollusca on Gueishan Island.

Sampling

Literature survey: We searched for publications (including journals, project reports, thesis and books) associated with the molluscan fauna of Gueishan Island from the following databases: (1) the National Digital Library of Theses and Dissertations in Taiwan (http://ndltd.ncl.edu.tw) (this contains details of theses and dissertations published since 1956, but did not contain publications relevant to this study); (2) the National Bibliographic Information Network (http://nbinet3.ncl.edu.tw) (this catalog integrates information from National Central Library and 74 other libraries containing all publications with a Taiwan ISBN and selected government project reports; three publications (Wu 2002, National Museum of Marine Biology and Aquarium 2003, Hwang and Lee 2003) from this database met our requirement); (3) the Government Research Bulletin (http://grbsearch.stpi.narl.org.tw/GRB/) (this contains government project reports made since 1993, but did not contain reports relevant to this study); (4) Google Scholar (http://scholar.google.com.tw/) (this contains a wide range of resources, from journals and books to webpages, and it provided two relevant journal articles (Chen and Fu 2007, Lee and Chen 2010)); (5) The Taiwan Malacofauna Database (http://shell.sinica.edu.tw/) (this database contains taxonomy, distribution and references of all mollusks occurred in Taiwan, and provided six relevant publications (Lee and Wu 1998, Jung and Lai 1999, Wu 2002, National Museum of Marine Biology and Aquarium 2003, Hwang and Lee 2003, Chen and Fu 2007)). In addition, three relevant publications (Hayasaka and Tan 1934, Kuroda 1938, Kuroda 1941) were identified from citations in Wu (2002). In total, we identified ten relevant publications. Three of these publications (Lee and Wu 1998, Chen and Fu 2007, Lee and Chen 2010) were excluded because they described specimens acquired from fishing ports that had been captured by shrimp fishing or bottom trawling boats near Gueishan Island, without information of the sampling location. The seven remaining publications were used to establish the occurrence and inventory data. Sampling sites, names of collectors and the scientific name of each species were recorded using Microsoft Excel 2010. All of the publications mentioned above can be accessed in the National Central Library and the National Taiwan Library. Field Sampling: The topology of Gueishan Island and the types of mollusk habitat were considered for field investigation. A visual search was conducted for mollusks in intertidal, freshwater and terrestrial environments (Figure 1). The surface of rocks on the southern coastline and man-made concrete structures in port were searched for marine mollusks during low tide. Leaf litter and rocks under or near water around Tail Lake (the only freshwater habitat on island) were inspected for freshwater mollusks. We inspected from leaves, trunks, leaves litter, rocks and rotten woods for land snails along three trails; one trail is around Tail Lake, another leads to the highest peak (401 Highland) on the island, and the other leads to the northern part of the island. We surveyed for land snails during their active periods: during and after rainfall, and in the early morning and at night. At least one living individual or dead shells of each species was collected as voucher specimens. Living organisms were brought back to laboratory, fixed via freezing in a -80℃ freezer, and subsequently transferred to 95% ethanol for long term preservation.

Quality Control

Latitude, longitude and altitude of sampling sites were recorded using Garmin GPSmap 60CSx with uncertainty of less than 10 meters. Sampling sites were georeferenced (WGS84). All the specimens collected by the field investigation were identified independently by Huang and Hsiung. Seven earlier studies described the mollucan fauna of Gueishan Island, but these publications lack clear photos or other information for identifying specimens. Species identification was performed using the following guide books and publications about Taiwan malacofauna: Pace (1973), Lai (1990, 1998), Lee and Chen (2003), Wu and Lee (2005), and Hsieh et al. (2006). New recorded species were further confirmed by Yen-Chen Lee, Mollusca specialist and postdoctoral researcher in the Biodiversity Research Center, Academia Sinica. Fourteen new recorded species were found to be native to Taiwan but previously unreported on Gueishan Island. The scientific names of all mollusks were checked against the Taiwan Malacofauna Database (http://shell.sinica.edu.tw/) and World Register of Marine Species (http://www.marinespecies.org/).

Method steps

1. Species identification were based on Pace (1973), Lai (1990, 1998), Lee and Chen (2003), Wu and Lee (2005), and Hsieh et al. (2006).

The coverage of this dataset includes 126 species from 71 genera and 45 families of Mollusks of marine, freshwater and terrestrial environments on Gueishan Island. It includes Class Gastropoda (88.10%), Class Bivalvia (8.73%), Class Cephalopoda (1.59%), and Class Polyplacophora (1.59%). The top five representative families are Cypraeidae (20 species, 15.87%), Trochidae (13 species, 10.32%), Muricidae (11 species, 8.73%), Neritidae (8 species, 6.35%), and Littorinidae (5 species, 3.97%)

1. Mollusca
   rank: phylum
2. Gastropoda
   common name: snail rank: class
3. Bivalvia
   common name: bivalves rank: class
4. Cephalopoda
   rank: class
5. Polyplacophora
   rank: class

The spatial coverage of the literature and our field investigation ranged from a latitude of 24°49'48''N to 24°51'0''N and a longitude of 121°55'48''E to 121°57'36''E. It includes the marine, intertidal, freshwater and terrestrial environment of Gueishan Island, Taiwan