Native or invasive? Biodiversity, distribution and systematics of Ostracoda (Crustacea) in Japanese rice fields

2020 Fiscal Year Research-status Report

• Project/Area Number: 20K06807
• Research Institution: Lake Biwa Museum
• Principal Investigator: Smith Robin 滋賀県立琵琶湖博物館, 研究部, 専門学芸員 (70416204)
• Co-Investigator(Kenkyū-buntansha): 神谷 隆宏 金沢大学, 地球社会基盤学系, 教授 (80194976)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: Ostracoda / new species / alien species / rice fields

Outline of Annual Research Achievements

New data collected from rice fields, in addition to samples already collected before the project commencement, has helped to identify the main species that inhabit rice fields, and highlight species that are opportunistic visitors to this type of habitat. With the addition of this data to a database of ostracod occurrences in North East Asia (curated by the PI), it is now possible to plot the known distributions of species in North East Asia. Detailed analyses of particular species to elucidate their taxonomy, and thus improve identification, is ongoing. A manuscript was written with Japanese colleagues about a probable alien species collected from Japanese pet shops, which we consider to be a potential invasive threat to rice field ecosystems (currently in press).

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

Covid-19 has delayed some aspects of the project, such as field work in different areas and meetings between the PI and Co-I. However, due to the large amount of data already collected, and the samples taken before the commencement of the project, together with new samples taken in Shiga, these delays are not expected to be a serious hindrance. Covid-19 has, however, greatly impacted the attendance of scientific conferences at which we were planning to report our results. The fourth Asian Ostracod Meeting was postponed from November 2020, and the International Symposium on Ostracoda has been postponed from 2021 to 2022.

Strategy for Future Research Activity

The main original concept of the project is to target the rice field ostracod faunas in order to identify possible invasive species. This is a sound concept and has a lot of potential in highlighting possible alien species. However, it can be complemented by research into possible routes of invasive species. One of these is the pet trade, as shown by the discovery of probable alien ostracod species from pet shops in the Kanto region of Japan. Many unwanted pets are released into the environment, and if this is done in irrigation channels or ponds connected to rice fields, there is the possibility that a species will become established in the rice field ecosystem. We are therefore looking at expanding the field work to include the sampling of ponds and irrigation channels for rice fields.