Abstract

Study on the functional feeding group (FFG) structure of aquatic insects in upstreams of Da Nhim river to understand the ecological functional groups in the watershed. The study investigated two headwater streams (A and B) of upper Da Nhim river in the dry and rainy seasons 2013). Quantitative sampling, diversity indices, grouping the FFGs and analysing correlation between the FFGs conducted in each season. Results showed that: (1) Shannon - Weiner indices (H') were 3.0-4.4, and Simpson indices (λ) were 0.06-0.13; (2) The FFG structure included five groups: collector - garthering (cg) (46 %), scrapper (sc) (31 %), collector - filtering (cf) (12 %), predator (p) (8 %) and shredder (sh) (3 %); (3) The correlations were possitive and stability in seasons. Shredder (sh) implied the intact riparian vegetation; and the occurrence of predators in both two seasons, implied the nutrient balance in the stream ecosystem. The FFG structures should be documented in the continuing lower reaches of the Da Nhim river to fulfill data in the whole system of Dong Nai river