Research

My research focuses on linkages between stream and riparian ecosystems. I am particularly interested in understanding how terrestrial resource subsidies affect intra/inter specific interactions, community structure and ecosystem functions in stream ecosystems. I am seeking to develop a general framework to conserve/ manage stream and riparian habitats as an integrated system.

The two main themes are below:

1) Parasite-mediated resource subsidy and stream ecosystems
2) Conservation of endangered native stream salmonids

Current Project:

The parasitic life history has arisen on multiple independent evolutionary occasions in many phyla, and now parasites account for a large proportion of living species and biomass on Earth. Nevertheless, the parasites have often been overlooked in community and ecosystem ecology.

Parasitic nematomorphs (Nematomorpha: Gordioidea) manipulate their terrestrial invertebrate hosts to seek and jump into waters so that adult worms can emerge and mate. I found that through the behavioral manipulation of their hosts, nematomorphs indirectly enhances terrestrial invertebrate subsidy for aquatic predator, e.g., stream salmonid fishes, in stream ecosystems in Japan (Sato et al. 2008 CJZ; Sato et al. 2011 Oikos); accounted for 60% of annual energy intake of an endangered charr population Salvelinus leucomaenis japonicus in a Japanese mountain stream (Sato et al. 2011 Ecology).

Based on these studies, I am working on (1) community- and ecosystem level effects of the host manipulation by nematomorphs (Sato et al. 2012 Ecol Lett.), (2) species diversity of nematomorphs and co-habiting nematodes (e.g., Mermithidae) (Sato et al. CJZ in press), (3) geographic variation of host-parasite interactions and its ecosystem-level consequences. Our studies will provide an excellent model to deepen our understanding of how host-parasite diversification play a role in structuring complex ecological communities and ecosystem functions through time.