TABLE CONTENTS

POSTER PRESENTATIONS
TOPIC ONE – EVOLUTION, PHYLOGENY AND CLASSIFICATION
Nematode Fauna of a Biotope Pond Sediment Compared with Surrounding
Marsh and Rice Paddy Fields in the Kanto District, Japan
Araki, M.
National Institute for Agro-Environmental Sciences
The function of agricultural land in conserving the environment and biodiversity has been
widely noticed recently and it is important to understand the nematode biodiversity in paddy
fields, which is the most common land use in Japanese arable land, as well as the damp
environments surrounding them. Imamura (1931) gave a splendid list of nematodes in rice
paddies in Tokyo, Kanto district. However, little work has been done since then to
investigate the nematode fauna of rice paddy. The situation is the same in wetlands, ponds or
rivers in agricultural ecosystems. I had the opportunity to investigate nematode fauna in a
biotope pond, marsh and rice paddy in Koibuchi College of Agriculture and Nutrition in
Ibaraki Prefecture, Kanto district in 2006-2007. The biotope consisting of the pond and a
marsh planted with Manchurian wild rice (Zizania latifolia) was created on the paddy field in
2004. Surrounding rice paddy has been cultivated in a conventional or organic way. Pond
sediments were taken on October 2007 and soil samples were taken on June 2006 after riceplanting
and on January and October 2007 from fallow paddy. Nematodes were extracted
from the samples by sieving followed by modified Baermann technique using trays. The
major nematode genus in pond sediments was Tripyla, and family Rhabditidae, genera
Plectus, Chronogaster, Rhabdolaimus, Prismatolaimus, Ironus, Mononchus and Dorylaimus
etc. were detected. The nematode fauna of the conventional rice paddy is similar to that of
pond sediments, but the most common genera in conventional rice paddy were Rhabdolaimus
and Dorylaimus. Chronogaster was one of the most abundant genera in the organic rice
paddy though genus Rhabdolaimus was also very common. The marsh bore few nematodes
as well as the pond sediments characterized by genus Plectus. It seems that pond sediments
and rice paddy have different nematode fauna.
5 th International Congress of Nematology, 2008 187