Dryophytes suweonensis 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Amphibia Anura Hylidae

Scientific Name: Dryophytes suweonensis (Kuramoto, 1980)
Common Name(s):
English Suweon Treefrog
Hyla suweonensis Kuramoto, 1980
Taxonomic Source(s): Duellman, W.E, Marion, A.B. and Hedges, S.B. 2016. Phylogenetics, classification, and biogeography of the treefrogs (Amphibia: Anura: Arboranae). Zootaxa 4104: 1-109.
Taxonomic Notes: This is a distinct species from the sympatric Hyla japonica (Kuramoto 1984, Yang and Park 1988, Lee and Park 1992, Lee et al. 1999,  Jang et al. 2011, Borzée et al. 2013).

The genus Dryophytes was resurrected from synonymy under Hyla by Duellman et al. (2016) and this species was transferred from Hyla to Dryophytes.

Assessment Information [top]

Red List Category & Criteria: Endangered A2ace+4ace; B1ab(i,ii,iii,v); C1 ver 3.1
Year Published: 2017
Date Assessed: 2014-03-03
Assessor(s): IUCN SSC Amphibian Specialist Group
Reviewer(s): Hilton-Taylor, C.
Contributor(s): Borzee, A. & Matsui, M.
Facilitator/Compiler(s): Angulo, A.
Listed as Endangered given a population decline estimated to be 50% over the last ten years due to a decline in the area of occupancy (AOO) and extent of occurrence (EOO); because it has an EOO estimated at 4,031 km2, its population is considered to be severely fragmented, and there is continuing decline in its AOO, EOO, habitat, and number of mature individuals; and because there are an estimated 500-600 mature individuals, with a projected 20-50% decline in the next six years.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This is a very narrowly distributed species, restricted to the lowlands of western central Korea on an area of 30 km by 50 km (Yang et al. 2001, Kim et al. 2012). Its elevational range varies from 8-90 m asl (A. Borzee pers. comm. March 2014). Although remnant population could hypothetically be found on western lowlands of both South and North Korea, the range is not considered to be much greater than currently understood. Its current extant range, taken as a proxy for extent of occurrence (EOO), is estimated to be 4,031 km2, and it is considered to occur in about seven threat-defined locations (A. Borzee pers. comm. March 2014). The current map also depicts areas where the species has been extirpated, namely Suweon, Kangwa Island and Pyeongtaek.
Countries occurrence:
Korea, Republic of
Additional data:
Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:4031
Continuing decline in extent of occurrence (EOO):Yes
Number of Locations:7
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:It is considered to be a rare species, with calling indexes developed by the North American Amphibian Monitoring Program peaking during the first three weeks of May at a significantly lower maximum that the calling indexes of the related H. japonica (A. Borzee pers. comm. March 2014). The totality of its population appears to be severely fragmented because its range matches with the metropolitan city of Seoul, and it is difficult if not impossible for individuals to disperse between patches due to distance and landscape elements (A. Borzee pers. comm. March 2014). A population estimate in 2012 covering several dozen localities, although not including all subpopulations, led to the conclusion that only 260 calling males are remaining (Kim et al. 2012). Assuming a sex ratio of 1:1, the population size could therefore oscillate around 500-600. The main part of the global population is found in Gyeonggi province while some additional subpopulations are found in the provinces of south and north Chungcheong and Gangwon provinces (A. Borzee pers. comm. March 2014). Previously known subpopulations in Suweon, Kangwa Island and Pyeongtaek have gone extinct during the last decade, and it is estimated that there has been a 50% population size reduction in this period (A. Borzee pers. comm. March 2014). Based on knowledge from closely related Palearctic tree frog species with similar ecologies, its generation length is estimated to vary between 1-3 years (A. Borzee pers. comm. March 2014). Using available information from the last decade, a 20-50% continuing population decline is projected to occur over the next two generations should there be no changes to its habitat (A. Borzee pers. comm. March 2014). 


Current Population Trend:Decreasing
Additional data:
Number of mature individuals:500-600Continuing decline of mature individuals:Yes
Population severely fragmented:Yes

Habitat and Ecology [top]

Habitat and Ecology:It has been observed in paddy fields. Larval development requires access to standing water and the species has not been observed breeding in natural wetlands, although anthropologically altered wetlands such as rice paddies are acceptable breeding grounds (A. Borzee pers. comm. March 2014). Both this species and the related H. japonica rely on the same habitat for breeding, and there is a microhabitat selection preventing a large recruitment of H. suweonensis females and increasing the risk of hybridization (A. Borzee pers. comm. March 2014).
Systems:Terrestrial; Freshwater
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):1-3

Use and Trade [top]

Use and Trade:

There are no reports of this species being utilized.

Threats [top]

Major Threat(s):

All of this species' subpopulations are affected by urbanization through the loss of breeding and hibernating sites and the increasingly lower connectivity between each remaining population (A. Borzee pers. comm. March 2014). In addition, this treefrog's ecology makes it particularly vulnerable to agricultural activity, given that the species’ daytime resting place is located at the very edge of rice paddies, which are more prone to agricultural mowing, consequently leading to a high mortality rate (A. Borzee pers. comm. March 2014).

Conservation Actions [top]

Conservation Actions: It is not known from any protected areas. Since 2012 this treefrog has been considered an endangered species by the Ministry of Environment of the Republic of Korea (Ministry of Environment of the Republic of Korea 2012). Habitat protection is urgently needed to assist the persistence of this species. Population monitoring is required to monitor trends across its global population.

Amended [top]

Amended reason: This amended assessment has been created because the species was transferred from the genus Hyla to Dryophytes.

Citation: IUCN SSC Amphibian Specialist Group. 2017. Dryophytes suweonensis (amended version of 2014 assessment). The IUCN Red List of Threatened Species 2017: e.T55670A112715252. . Downloaded on 18 June 2018.
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