Sampling event

A dataset of distribution of the Geothelphusa (Decapoda: Potamidae) with their environmental parameters and stream indicators in eastern and southern Taiwan

Latest version published by Taiwan Biodiversity Research Institute on 06 February 2023 Taiwan Biodiversity Research Institute
Publication date:
06 February 2023
CC-BY 4.0

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This dataset includes data of the freshwater crab genus Geothelphusa (Decapoda: Potamidae), their environmental parameters and stream indicators in eastern and southern Taiwan. This dataset is the result of 146 surveys (sampling events) of freshwater crab species and stream environment from 2013 to 2015 in 42 sampling sites throughout Taiwan, and a total of 12 species and 1,006 crabs of the Geothelphusa were recorded. The crab data include ‎existence or not, carapace width, carapace length, wet weight and sex. The stream environmental data include water temperature, pH value, dissolved oxygen, conductivity and three indicators (River Pollution Index, RPI; Water Quality Index 7, WQI7; citizen Qualitative Habitat Evaluation Index, cQHEI).

Data Records

The data in this sampling event resource has been published as a Darwin Core Archive (DwC-A), which is a standardized format for sharing biodiversity data as a set of one or more data tables. The core data table contains 146 records.

2 extension data tables also exist. An extension record supplies extra information about a core record. The number of records in each extension data table is illustrated below.

Event (core)

This IPT archives the data and thus serves as the data repository. The data and resource metadata are available for download in the downloads section. The versions table lists other versions of the resource that have been made publicly available and allows tracking changes made to the resource over time.


The table below shows only published versions of the resource that are publicly accessible.

How to cite

Researchers should cite this work as follows:

Huang C, Yang C (2023): A dataset of distribution of the Geothelphusa (Decapoda: Potamidae) with their environmental parameters and stream indicators in eastern and southern Taiwan. v1.6. Taiwan Endemic Species Research Institute. Dataset/Samplingevent.


Researchers should respect the following rights statement:

The publisher and rights holder of this work is Taiwan Biodiversity Research Institute. This work is licensed under a Creative Commons Attribution (CC-BY) 4.0 License.

GBIF Registration

This resource has been registered with GBIF, and assigned the following GBIF UUID: 0528b82f-bebb-49b0-ad2e-5082ae002823.  Taiwan Biodiversity Research Institute publishes this resource, and is itself registered in GBIF as a data publisher endorsed by Taiwan Biodiversity Information Facility.


Samplingevent Occurrence


ChihNan Huang
  • Metadata Provider
  • Originator
  • User
  • Point Of Contact
Assistant Research Fellow
Taiwan Endemic Species Research Institute
ChengHsiung Yang
  • Originator
  • Point Of Contact
Taiwan Endemic Species Research Institute

Geographic Coverage

There were 42 study sites ranging from 120.601295 to 121.6641944 and 21.95916 to 24.75119444.

Bounding Coordinates South West [21.959, 120.601], North East [24.751, 121.664]

Taxonomic Coverage

All the crabs were identified and recorded to species, but a few individuals labelled as "Uncertain" were too small to identify. There were 12 species and 1,006 crabs of the Geothelphusa recorded.

Genus Geothelphusa (澤蟹)
Species Geothelphusa albogilva (黃灰澤蟹), Geothelphusa bicolor (雙色澤蟹), Geothelphusa caesia (藍灰澤蟹), Geothelphusa cinerea (灰甲澤蟹), Geothelphusa ferruginea (銹色澤蟹), Geothelphusa ilan (宜蘭澤蟹), Geothelphusa lili (力里澤蟹), Geothelphusa olea (黃綠澤蟹), Geothelphusa pingtung (屏東澤蟹), Geothelphusa shernshan (神山澤蟹), Geothelphusa tawu (大武澤蟹), Geothelphusa tsayae (蔡氏澤蟹)

Temporal Coverage

Start Date / End Date 2013-06-14 / 2015-06-11

Project Data

No Description available

Title Constructing monitoring system for the freshwater ecosystem – The study on indicator species of the Geothelphusa
Funding Endemic Species Research Institute, Council of Agriculture, Executive Yuan, Taiwan
Study Area Description Twenty-two sites (52.4%) have been monitored from 2011 located in southern Taiwan, and the other 20 sites are located in the eastern Taiwan.

The personnel involved in the project:

ChihNan Huang

Sampling Methods

Crab investigation A complete search of 50 meters along the stream was conducted at each site. Then, six traps baited with dry pet food (Fig. 2) were set overnight (Chen et al. 2003) to collect the Geothelphusa crabs. After identifying species and measuring the traits of carapace breadth, carapace length, wet weight and sex, the captured crabs were released to their native habitats except for those with doubt in species identification needed for confirmation in the laboratory. Environmental parameters investigation The water temperature, pH value, dissolved oxygen and conductivity of the sampling sites were measured by a water quality meter (Horiba U-53) in situ. The water samples used to measure the values of BOD5, NH3-N, SS, FC and TP were preserved below 4 degree Celsius and analyzed in the laboratory within seven days from collection. In addition, the score table of cQHEI was also recorded in situ. The data of BOD5, NH3-N, SS, FC and TP were used to calculate two water quality indicators: River Pollution Index (Liou et al. 2004) and Water Quality Index 7 (Wen 2006). The data of the score table of cQHEI were used to calculate the other environmental indicator: the citizen Qualitative Habitat Evaluation Index (Hoosier Riverwatch 2019).

Study Extent The freshwater crabs appear in almost all clean freshwater bodies, from moist lowland forests to rugged mountains (Cumberlidge et al. 2009). There are 57 recognized Geothelphusa species, with 39 species in Taiwan (Shy et al. 2021). Over twenty Taiwanese Geothelphusa species live in stream ecosystems below 500 m above sea level (Shy and Lee 2009). In this paper, the 42 sampling sites in Taiwan (Fig. 1) are all natural habitats of streams with an elevation distribution of 2-998 m, and 33 sites (78.6%) are below 500 m altitude. The data of the 22 monitoring sites were collected quarterly from the summer of 2013 to the summer of 2015, but some surveys were abandoned due to a lack of water-related data for the drought. The other 20 sites were surveyed only once in the summer and fall of 2014.

Method step description:

  1. The water sampling and the seven parameters required to calculate two water quality indicators, River Pollution Index and Water Quality Index, including pH value, dissolved oxygen (DO), biochemical oxygen demand (BOD5), ammonia nitrogen (NH3-N), suspended solids (SS), fecal coliform (FC) and total phosphorus (TP), were operated following the protocols published by Taiwan Environmental Protection Administration in 2013.

Additional Metadata

Alternative Identifiers 0528b82f-bebb-49b0-ad2e-5082ae002823