Investigation of macroinvertebrate communities change in the Anzali international wetland and its streams, since 1990s to 2018

Macroinvertebrates communities are vital components of wetland and river ecosystems. Increasing population growth and human activities, including agriculture and urban wastewater, it has an impact on the water ecosystem. The nature of the aquatic environment of the wetland and its margin is influenced by human activities, which affects its composition and abundance of organisms throughout the aquatic environment. The present study was carried out on the macroinvertebrates community and sediment particle size and organic matter that sampled with Ekman grab in Anzali wetland and its streams since the 1990s to 2018 in order to investigate their changes in 4 seasons and 3 replicates in 2016. Then, the present data were compared with the information obtained by other researchers at the similar station from 1980 to the 20s in order to examine the trend of its changes over the past three decades. The present study showed that of 17 families of benthic invertebrates including 3 phyla, 5 class, and 9 order, thehighest abundance was Tubificidae (58%) and Chironomidae (38%), which indicates the dominance of these two families in Anzali lagoon. According to the studies conducted over the last three decades until now, the abundance of these two families has been increasing. In general, the increase in the family Tubificidae and Chironomidae in one area can be due to increased urban wastewater and agriculture and the destruction of the marginal wetland forests. The most abundance in different seasons belonged to spring and the lowest was summer. In terms of sediment particle size, over the years, dominance has been observed with silt and clay and the amount of organic matter was in the range of 5 to 20 percent. The process of changes in benthic organisms was shown that about 21 families have been identified in similar studies in the past three decades, which indicates a decrease in the diversity of benthic species within the wetland. For example, Ephemeroptera, Cumacea, Bivalvae, Culicidae observed in the past (from the 80s to 20s) was not found in the present study. Due to the increase in the flow of wastewater and the increase of agricultural activities and the destruction of marginal species of species diversity in the wetland has decreased and has increased the resistantspecies.

کلیدواژه ها:

Bioindicatore ، Macroinvertebrates ، Environmental parameter ، Anzali international wetland