The significance of riparian communities in the energy flow of subtropical stream ecosystems

• Published in: Aquatic sciences Vol. 84; no. 2; p. 20
• Main Authors: Liao, Yi-Chang, Lin, An-Cheng, Tsai, Han-Ni, Yen, Yu-Ting, Tzeng, Chyng-Shyan, Yang, Man-Miao, Lin, Hsing-Juh
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.04.2022; Springer; Springer Nature B.V
• Subjects: Analysis; Aquatic ecosystems; Aquatic habitats; Aquatic insects; Arthropoda; Arthropods; Biomedical and Life Sciences; Ecology; Ecosystems; Energy flow; Environment models; Environmental aspects; Environmental degradation; Environmental Management; Fishes; forests; Freshwater & Marine Ecology; Functional groups; habitats; Insects; Insects, Aquatic; Life Sciences; Marine & Freshwater Sciences; Oceanography; omnivores; Research Article; Riparian land; Riparian vegetation; Rivers; Streams; Tributaries; Trophic levels; Ecopath; Keystoneness; Aquatic insects; Network analysis; Ecotrophic efficiency
• ISSN: 1015-1621; 1420-9055
• DOI: 10.1007/s00027-022-00850-x

There is a frequent energy flow connection between streams and riparian zones. However, riparian communities have been limited in studies of stream ecosystems. To understand the significance of riparian communities in the energy flow of stream ecosystems, we compared two trophic models in a small forest tributary (the Feifong Stream) and the mainstream (the Houlong Stream) that possessed high and low biomasses of riparian vegetation and arthropods, respectively. There were 25 functional groups classified into 3 integer trophic levels in the two trophic models. Arthropods, mostly insects, were the main carrier of the energy flow between aquatic and riparian habitats. The feeding connections were more extensive and intensive in the tributary than in the mainstream, as riparian arthropods were more abundant in the tributary. When including the riparian community in the tributary, the trophic model became more mature, as the values of system omnivory index and trophic transfer efficiency and the ascendency: capacity ratio were higher, but the connectance index value and overhead: capacity ratio were lower in the model with riparian groups than in the model without riparian groups. In the tributary, the ecotrophic efficiency (EE) values of aquatic insect groups increased largely if the riparian community was included in the model. In the mainstream, however, most of the ecosystem attributes and the EE values of aquatic insect groups did not obviously change if the model included the riparian community. This study highlights the significance of riparian communities in the energy flow of subtropical stream ecosystems. Aquatic and riparian systems should be considered together as a mature ecosystem for the planning of stream conservation. The loss or degradation of one habitat may have more detrimental effects on the other community than we have previously recognized, particularly in a small forest stream.