Impact Of Fishing Methods On The Trophic Structure And Function Of Ecosystem In The Subsidence Lakes Of Coal Mining Areas

The collapse of coal mining in Huainan has played a very important role in the ecological restoration of the mining area.Understanding the structure and function of its ecosystem is an inevitable requirement for the rehabilitation of the mining area.At present,the fishing methods of different coal mining collapse lakes are quite different andhave potential impacts on the structure and function of the lake ecosystem.Explainingthat the impact mechanism is helpful for the scientific management of water areas,it can provide a theoretical basis for the ecological restoration of mining areas.In this study,two small collapsing lakes Panxipanji(PXPJ)and Huaixi Lake(HXH)with large differences in fishing methods in Huainan were selected.Samples were collected monthly in 2016,and their water environment characteristics and plankton community structure were analyzed.Based on the investigation of the catch situation,the Ecopath model was used to analyze the structure and function of the ecosystem,and the structure and characteristics of the PXPJ and HXH ecosystems under the influence of different fishing methods were compared.The main results and conclusions are as follows:During the 2016 survey period,PXPJ observed a total of 93 species of 7 phyla,53 genera and 7 species of phytoplankton,of which 44 species were Chlorophyta,which accounted for 47.3%of the total number of phytoplankton species.Cyanophyta and diatoms accounted for 20.4%and 19.4%respectively.HXH observed a total of 89 species of 6 phylums and 50 genera of phytoplankton.The number of species of Chlorophyta was up to 48,accounting for 53.9%of the total number of phytoplankton species,followed by 15 species of Diatoms and Cyanophyta,each accounting for phytoplankton.16.9%of the total number of species.During the 2016 survey,a total of 17 species of planktonic crustaceans were observed in PXPJ,including 11 species of Cladocera,5 species of Copepod,and 1 species of unorganized larvae.At the same time,19 species of 8 genuses of Rotifera were observed,of which the tail was observed.There are 5 species of genus and 5 species of genus,5 species of genus,5 species of different genus,2 species of cystic genus,1 species of genus,rhinoceros,multi-legged genus,and trigeminal genus.A total of 14 species of planktonic crustaceans were observed in HXH,including 8 species of Cladocera,5 species of copepods,and 1 species of unorganized larvae.At the same time,17 species of 10 genuses were observed in Rotifera,of which 5 species belong to Brachiosaurus.There are 3 species of different genus,2 species of cystic genus,1 species of genus Rhinoceros,and Rhinoceros.During the 2016 survey,PXPJ surveyed a total of 17 species of fish and shrimps,and the total biomass harvested was 89.8 t/km2.Among them,white plover,calyx,squid,and squid were the main economic fish,which occupies the total fisheries of the fishery.The proportions were 34.9%,22.6%,9.92%,9.52%and 7.64%,respectively;HXH surveyed a total of 18 species of fish and shrimp,and the total catch of fish and shrimp was 397 t/km2,of which the white peony and flower pod were used.As the most important economic fish,its share of total catches was 88.2%and 9.45%,respectively,while other fish and shrimps accounted for only 2.32%of the biological catch.The Ecopath model divides the two lakes into 18 functional groups.The simulation results show that the TPP/TR(2.56)of the PXPJ ecosystem is closer to 1 than the TPP/TR(3.05)of the HXH ecosystem,and the model outputs the PXPJ ecology.Other indicators of the system such as system connection index(CI),system omnivorous degree(SOI),cycle index(FCI),and circulation path length(FCL)are all higher than the HXH ecosystem;the total flow value of the HXH ecosystem(27776t·km-2·year-1)is much higher than the PXPJ ecosystem(13212 t·km-2·year-1),and the total food intake,total output,total respiration,and total flow debris are higher than those of HXH.PXPJ ecosystem.The results show that the PXPJ ecosystem food network structure of the decentralized fishing system is more complex and more stable than the HXH ecosystem,and the energy transmission efficiency of the ecosystem is higher.