|Budget Amount *help
¥2,600,000 (Direct Cost : ¥2,600,000)
Fiscal Year 1999 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1998 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1997 : ¥1,800,000 (Direct Cost : ¥1,800,000)
Food and habitats are two major requisites for all organisms. Intra- and inter-specific interactions for food acquisition have been investigated as foraging theory, prey-predator interactions and food web analyses. There have been many theories on habitat segregation, habit structure, symbiosis and habitation chain. Very few attempts, however, have been conducted for constructing theories uniting such two major requisites.
The aim of this study is to construct interaction webs connecting food chain and habitation chain for intertidal mussel bed community and aquatic animal community within riverine hygrophyte stands. Seasonal and monthly surveys for species composition, population density of component species and food preference were conduced for both communities from 1997 to 1999. Laboratory experiments on the foraging behavior and food selection of component species revealed the prey-predator interactions within the food selection of component species revealed the prey-predator interactions within the mussel beds.
According to the results of the field surveys and laboratory experiments, food chain and habitation chain among the component species could be constructed. Two kinds of indirect interactions, those acting through two or three fold food chains, and those acting between species providing with habitats and symbionts, could be discriminated. Then an interaction web connecting food chains and habitation chains could be constructed by adding indirect interactions between the symbionts to the food chains. The same procedure was adopted to an aquatic animal community within riverine hygrophyte stands, and an interaction web for community could be constructed. These results suggest that such interaction web can show the various kinds of interactions for acquisition of food and habitats and even the functional niche of component species in biological community.