Conservation ecology of the brackish water damselfly, Mortonagrion hirosei Asahina: dynamics of a newly established reed community (Zygoptera: Coenagrionidae)

The endangered M. hirosei perches in the understory of dense reed communities in brackish water. To aid the conservation of a population, a new reed community (2110 m2) was established in abandoned rice paddy fields adjacent to the original, threatened community (500 m2) by transplanting reed rhizomes in January 2003; brackish water was supplied to the new community. It was assessed whether the new community developed into a suitable habitat for M. hirosei by comparing it to the original community in 2005. Shoot height, density, and aboveground biomass of the reeds and relative light intensity in the community were measured periodically during the growing season. Reed height and biomass were significantly lower in the new community than in the original one. This suggests that 3 yr after transplantation the new community was still underdeveloped. However, shoot density and relative light intensity in the understory were not significantly different between the two communities. Thus, the new reed community was offered in 2005 to M. hirosei adults as a suitable habitat.