The rivers of Patagonia are some of the best conserved aquatic ecosystems in South America; however. However due to the growing economic development in the region, several bodies of water have been threatened by human activities. We analyzed the water quality and structure of macroinvertebrate assemblages at 8 stations along the Palena River; upstream, where there is minimal disturbance, and downstream, at stations perturbed by human activities. Samples were collected over the four seasons of the year (September 2013 to May 2014). Temperature, electrical conductivity, pH, dissolved oxygen, total hardness, silica, aluminum and iron showed significant differences (p < 0.05) between stations located upstream and downstream in the river basin, as well as between seasons of the year. A total of 30 macroinvertebrate families were registered (90% insect larvae), being Diptera the most diverse order (8 families). Leptophlebiidae family (Ephemeroptera) was the most abundant family in the four seasons of the year throughout. Statistically, there were significant differences (p < 0.05) between seasons of the year, which were grouped in two groups: one summer-fall and winter-spring, but not to macroinvertebrate assemblages between stations upstream and downstream. These findings indicate that the seasonal variations have a greater effect on the macroinvertebrates assemblage composition than the spatial differences in the basin. On the other hand, the great diversity of macroinvertebrates registered in the Palena River, in addition to the good water quality, indicate that the activities in the basin are not yet a risk to the aquatic ecosystem.
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Copyright (c) 2021 Carlos Leal-Bastidas, Luis Vargas-Chacoff, Natalia Sandoval, Pablo Fierro
Mito ya Patagonia ni moja ya mifumo bora ya mazingira ya majini katika Amerika Kusini. Hata hivyo, kwa sababu ya ukuzi wa kiuchumi katika eneo hilo, miili kadhaa ya maji imehatarishwa na shughuli za binadamu. Tuchunguza ubora wa maji na muundo wa makundi ya macroinvertebrate katika vituo nane kando ya Mto Palena; upstream, ambapo kuna usumbufu mdogo, na chini ya mto, katika vituo vya kusumbuliwa na shughuli za binadamu. Sampuli zilizochukuliwa zilikuwa zimetoka kwa kipindi cha miezi minne ya mwaka (Septemba 2013 hadi Mei 2014). Kiwango cha joto, conductivity umeme, pH, oksijeni dissolved, jumla ugumu, silika, alumini na chuma alionyesha tofauti kubwa (p < 0.05) kati ya vituo ziko upstream na downstream katika bonde la mto, kama vile kati ya misimu ya mwaka. Kwa jumla, familia 30 za macroinvertebrate zilirekodiwa (90% ya mabuu ya wadudu), na Diptera ni utaratibu wa aina nyingi zaidi (familia 8). Leptophilidae ni familia ya wanyama wa aina ya ephemeroptera, ambayo huishi katika majira manne ya mwaka. Kwa mujibu wa takwimu, kulikuwa na tofauti kubwa (p < 0.05) kati ya misimu ya mwaka, ambayo iligawanywa katika makundi mawili: moja majira ya joto-kuanguka na majira ya baridi-mapema, lakini si kwa makundi ya macroinvertebrate kati ya vituo juu na chini ya mto. Matokeo haya yanaonyesha kwamba tofauti za msimu zina athari kubwa juu ya muundo wa mkusanyiko wa macroinvertebrate kuliko tofauti za nafasi katika bonde. Kwa upande mwingine, utofauti mkubwa wa macroinvertebrate iliyohesabiwa katika Mto Palena, pamoja na ubora mzuri wa maji, inaonyesha kuwa shughuli katika bonde bado sio hatari kwa mazingira ya majini. Kazi hii ni leseni chini ya Creative Commons Attribution-NonCommercial 4.0 International License. Copyright 2021 Carlos Leal-Basted, Luis Vargas Chacoff, Natalia Sandoval, Pablo Fierro