Conservation Requirements for the Suweon Treefrog

New publication in collaboration with Il-Kook Park and Prof Daesik Park from Gangwon National University! Here, we highlight that the survival of Suweon treefrog populations is linked to non-fragmented rice paddy cover (as there is no natural habitat left). We also demonstrate that the presence of greenhouses and other infrastructures in rice paddy complexes has a significant negative impact on populations.

Habitat suitability for the Suweon treefrog (Dryophytes suweonensis) in Sihung, Republic of Korea, highlighting the areas where the species is extirpated, and the presence of greenhouses as their presence relates to the extirpation of the species at a site.

The Suweon treefrog (Dryophytes suweonensis) is threatened with habitat loss and most populations are under threat of extirpation. Over the last decades, sub-populations have become increasingly disconnected and specifically the density of paved roads has increased around the only site connecting northern and southern Seoul populations. We surveyed the locality in Hojobeol, Siheung, Republic of Korea to first confirm the decline in the number of sites where D. suweonensis was present. We then determined the remaining suitable habitat for D. suweonensis through a species distribution model.

Rice paddy cover and distance from the paved road are the most important factor defining suitable habitat for D. suweonensis. At this locality, uninterrupted rice paddies are a suitable habitat for the species when reaching at least 0.19 km2, with an average distance of 138 ± 93 m2 from the roads. We link the decrease in the number of sites where D. suweonensis is present with the decrease in rice paddy cover, generally replaced by localized infrastructures, greenhouses and habitat fragmentation. Rice paddies should remain connected over a large area for the protection of the remaining populations.

The PDF of the paper is available here.

Update on the range of Leopard cats (Prionailurus bengalensis) in Korea

CatNews 72 with our figure on the cover (Prionailurus bengalensis euptilrurus)

New collaborative paper with Kim Kyungmin from the National Institute of Ecology and Prof. Jang Yikweon from Ehwa Woman’s University. This is a landmark for the lab as it is the first mammal publication, but also, our figure made it to the journal cover! Congratulation Kyungmin for the pretty picture!

Whichever the species, knowing the exact distribution of wildlife is important for conservation planning of species. Exact ranges are usually difficult to determine, and it is important to address the lack of information present in the literature when we come across it, especially in public databases. This is especially true for species under threat as knowing where they occur is a pre-requisite step for the establishment of protected species.

The leopard cat Prionailurus bengalensis euptilrurus is the last felid species extant in the Republic of Korea, where it is listed as Vulnerable. Here, we present data supporting the current distribution of the leopard cat in the Republic of Korea, with a focus on the western lowlands. Based on this information, we call for an update of the species’ range on the IUCN Red List. In addition, we suggest an update to the range of the species in Jeju island, where the species is now regionally extinct.

Distribution of Leopard cats in the Republic of Korea. Figure extracted from CatNews 72.

I can send the PDF upon request.

Non-invasive sound recording for nation first Phylloscopus yunnanensis

In a publication in Forktail co-authored with Dr. Moores from Birds Korea, we demonstrated that, contrary to the long-established invasive practices where birds are killed, first records of presence can be established through non-invasive methods. Here we reported the presence of a Chinese Leaf Warbler (Phylloscopus yunnanensis) in the Republic of Korea through recordings of vocalisations.

Phylloscopus yunnanensis, on Baekryeong Island, Incheon, Republic of Korea, on 1 and 2 May 2020.  The above image is the best that could be takenby Dr. Moores in at least five hours of standing around in a wind-swept field…

We recorded and analysed a Chinese Leaf Warbler (Phylloscopus yunnanensis) on Baekryeong Island, Incheon, Republic of Korea, on 1 and 2 May 2020. This was the first adequately-documented national record of the species. The calls and song of this species are diagnostic, and identification in the field based on these vocalisations was straightforward and immediate.

There is a strong prevalence in many regions of the world to place much higher value on records confirmed by photographs, specimens or in-the-hand measurements than on records documented only with sound-recordings.

To avoid invasive methods, we analysed the recordings to confirm the bird’s identity. While the origins of a preference for visual documentation are understandable, a wider acceptance of the value of sound-recordings in documenting the presence or absence of species will likely prove immensely helpful in improving the understanding of the distribution, abundance and conservation status of many taxa which are morphologically extremely similar.

(A) Call and (B) persistent song of Phylloscopus yunnanensis, May 2020, Baekryeong Island, South Korea.

You can read the article below. Clicking on this link represents a direct request to the authors for a copy of the article.

How much more invasive can the four worst invasive amphibians become?

Duttaphrynus melanostictus, Rhinella marina, Lithobates catesbeianus, Xenopus laevis

In a new collaborative project led by Desiree Andersen from the Lab of Animal Communication at Ewha Womans University, we assessed the risk of invasion by the four most invasive amphibian species worldwide:  Duttaphrynus melanostictus, Rhinella marina, Lithobates catesbeianus and Xenopus laevis.

Invasive species have a massive impact on their environment and predicting geographical zones at risk of invasion is paramount to the control of further invasions. We modeled global habitat suitability for all four species using ecological niche factor analysis to predict the most susceptible areas to invasion. 

Models showed suitable climatic conditions for all four species expanded beyond their current native and invasive ranges. Tropical, subtropical, and island biomes around the world were among the areas with the highest ENFA suitability for all four species. Further, marginality statistics indicate niche expansion in D. melanostictus, and generalism in the three other species. As only climatic variables were used in the modelling, these results show the ultimate distributions if all landscape conditions are met without significant barriers to invasion. 

Suitability indices (left) and thresholded suitability of ecological niche factor analysis (ENFA) compared with native range and occurrence data (right) for Duttaphrynus melanostictusRhinella marinaLithobates catesbeianus, and Xenopus laevis. Thresholds are based on the maximum true skill statistic (TSS) of the model predicted by actual values. 

Seven Hynobius species in Korea!

Welcome to three newly described Hynobius salamander species from the Korean Peninsula! In a collaborative study with Prof. Mi-Sook Min from Seoul National University, we resolved the taxonomic questions related to the morphology and taxonomy of all seven Hynobius clade from the Korean Peninsula, and officially described the three species that have been known but not named for a few years.

Morphological variation between the seven Korean Hynobius species based on clade, patry and islandic populations

Morphological changes are common in populations of animals in response to environmental and evolutionary forces. This is the case for salamanders, which can adapt to most environments on earth. On the Korean Peninsula, Hynobius salamanders are widespread, with several species overlapping in distribution. In addition, while there are seven segregated clades based on mitochondrial DNA, only four of them have been described as segregated species and the three others are candidate species for which the species level of divergence has not been tested yet. Here we measured 329 individuals from all seven clades, in areas of range overlap or not, on islands and on the mainland (A on figure above), and tested for the species status of the three candidate species. Individuals on the mainland had a generally broader morphology than those on the islands (B on figure above), and individuals in the range overlap differed from the individuals from the same species that were not found in presence of another clade (C on figure above). Despite a significant impact of the island effect and the sympatric areas, all seven clades have significantly different morphologies, and we described Hynobius notialis, Hynobius geojeensis and Hynobius perplicatus.

Cryptic Uiryeong salamander (Hynobius perplicatus; 숨은의령도롱뇽)
Geoje salamander (Hynobius geojeensis; 거제도롱뇽)
Southern Korean salamander (Hynobius notialis; 남방도롱뇽)
Paratypes for all Hynobius species described in this paper: H. notialis, H. geojeensis and H. perplicatus. Field IDs are given above each individual.