| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2015: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2014: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2013: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Outline of Final Research Achievements |
The present study was to clarify the long-term impacts of clear-cutting and replanting on the stream ecosystems using multi-isotopes. Macroinvertebrates were collected in six streams of stand ages from 5 to >90 yr. The mean δ13C values of macroinvertebrates decreased with increasing stand ages. The result indicates the macroinvertebrates in old-stand ages depended more on terrestrial resources. From δ15N of amino acids, it was possible to estimate the contribution rate of aquatic vs. terrestrial resources and the trophic level of each taxon. The Δ14C values of both periphyton and grazers were lower than that of modern atmospheric CO2. These suggest that soil CO2 released by groundwater, and that dissolved inorganic carbon with low Δ14C is incorporated into stream ecosystems. The ecological response in the studied streams to forest managements is much slower than the chemical response. More than 50 yr is required for the food web structure to completely recover from clear-cutting.
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