Effects of human disturbance gradient on aquatic macroinvertebrate diversity: A study in a river of the Sierra Nevada de Santa Marta

Resumen

Understanding the environmental factors that shape macroinvertebrate diversity is particularly important because rivers in the neotropics are continuously affected by changes in land use. The main objective of this work was to analyze how environmental variables associated with different levels of human activity shape the macroinvertebrate community in the Ranchería River. Various environmental variables were measured at each of the nine sampling stations distributed across three gradients of human activity in the Ranchería River Basin. The sampling design included three stations in the high elevation zone (P9, P8, P7; 595 to 308 masl), three in the medium elevation zone (P6, P5, P4; 153 to 112 masl), and three in the low elevation zone (P3, P2, P1; 90 to 22 masl). For aquatic macroinvertebrates, five monthly samples were taken from January to May 2010 from these nine stations. A total of 4,615 individuals were collected, distributed across 16 orders, 54 families, and 83 taxa. The taxa with the highest relative abundance were Simulium (Diptera), Melanoides sp. (Thiaridae), and Orthocladiinae (Diptera: Chironomidae), with 20, 11, and 9% respectively. It was found that anthropogenic impacts shape the environmental variables and the structure of macroinvertebrate communities in the Ranchería River Basin.

Keywords: anthropic affectations, canonical correspondence analysis, Hill numbers, Rancheria River, Sierra Nevada de Santa Marta.