Latest research results on the structure of insect community in Trang An World Heritage Site in Ninh Binh

14/05/2020
About 90 km southeast of Hanoi, Trang An scenic complex in Ninh Binh province is home to cultural quintessence and natural beauty. The typical topography of this area is limestone mountains formed in the last geological stages. The process of geological tectonics over a long time created spectacular landscapes with steep cliffs, covered with tropical evergreen forests, surrounding submerged valleys connected with countless caves and underground rivers and streams. In 2014, UNESCO recognized Trang An Landscape Complex as a World Natural and Cultural Heritage.

Despite being a well-known site for both natural landscapes, historical sites and spiritual tourism, studies of fauna (especially insects) in this area are limited. Studies on the aquatic system in Ninh Binh province’s limestone area, including Trang An, which recorded the presence of 21 water species (Tran Duc Luong and cs., 2011), show that there is no information on terrestrial insects in this area.

Stemming from that practical need, VAST has assigned project "Researching the structure of insect community in Trang An World Heritage Site, Ninh Binh Province" with code VAST.04.06/18-19 to Institute of Ecology and Biological Resources to implement from January 1, 2018 to December 2019. The project belongs to biodiversity and active substances with biological activity, by Dr. Pham Thi Nhi.

After the two year implementation, the project has obtained the following results:

A total of 604 insect species of 431 genera, 91 families and 10 orders were recorded at Trang An World Heritage Site. A new species has been discovered for science in the family of small cocoon bees (Hymenoptera: Braconidae): Streblocera (Eutanycerus) trangana Long & Pham (in press). Besides, 16 species of fauna were recorded for the first time in Vietnam, including two species of beetle (Coleoptera), two species of the squid wing (Lepidoptera) and 12 species of the hymenoptera (Hymenoptera).

Structure: The subject analyzed the composition of families, varieties and species in each insect set; identified dominant insect families in terms of number of families (Coleoptera and Lepidoptera), number of breeds and species (Lepidoptera); analyzed the structure of species composition in families and genera, thereby identifying the insect family with the most diverse species (Noctuidae and Nymphalidae) and the insect species with the most species (Aleiodes and Neocollyris). The project also identified insect pests on agricultural crops, natural enemies and economically significant species in the study area.

New species of small cocoon bee, Streblocera (Eutanycerus) trangana Long & Pham (in press)

Distribution characteristics: Samples were collected at 6 locations and analyzed at each site to find the similarity in insect species composition between sites. An analysis of species similarity was also conducted between Trang An World Heritage site (Coleoptera and Lepidoptera groups) and several locations in the North. The study sites were divided into three habitat types, analysis of species number, Shannon-Weiner diversity index (H ') and Margalef (d) abundance index in each habitat, as well as the similarity level in species composition among habitats were conducted to determine the habitat with the highest level of insect diversity, and the lowest in the study area.

Conservation value: In addition to a newly discovered insect for science, the project recorded two species of conservation value in Trang An World Heritage Site, including:

- Troides aeacus aeacus (Papilioninae) This insect was named in the Vietnam Red Book (2007), VU (endangered);
- Scarlet Cosmiomorpha (Microcosmiomorpha) pacholatkoi Jákl (Scarabaeidae Scarab). This species is endemic to Vietnam. This species has just been recorded in Tam Dao National Park and Trang An World Heritage Site.

Based on three criteria including the total number of recorded species, the total number of species of conservation value and habitat quality, the thesis has identified the highest conservation priority level for the insects in the area of study.

Based on the results of the field survey, it has been determined that the construction of facilities and tourism development have impacts on biodiversity in general and insects in particular, narrowing the living environment, changing landscapes and causing ecosystem fragmentation. Since then, the project has made a number of recommendations for conservation.

About the product of the project: The project has handed over 200 insect samples to the Vietnam National Museum of Nature and supported the training of one graduate student of Hanoi National University of Education (successfully defended in November 2019) . The research team participating in the project has published two journal articles in the ISI list: 01 article in Zootaxa (SICE), 01 article in Raffles Bulletin of Zoology (SCI) and 02 articles in water (Journal of Biology).

With the results obtained, the project has evaluated the structure of the insect community in Trang An, on the one hand to explore the outstanding biodiversity values of the world heritage site,  and on the other hand to provide scientific foundations for nature conservation and sustainable tourism development in this special landscape of Vietnam.

The project was evaluated Excellent by VAST Acceptance Council February 12, 2020.

Translated by Tuyet Nhung
Link to Vietnamese version

 



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