Fish community dynamics in a water-stressed ecosystem: a case study from the endorheic basin in the semi-arid Mediterranean region

OpenAlex İngilizce

Abstract The endorheic Burdur Basin (Türkiye) is a region rich in endemism, but the water budget/quality has been damaged in last years. Since it is important to monitor fish diversity, which is known to respond rapidly to declining/polluted water resources, this study aimed to highlight the problems threatening the stock status of fish communities in the basin. Fish species and environmental variables were sampled in 12 lotic and 10 lentic habitats in the basin during wet and dry periods. Fifteen fish species were captured, seven of which were non-native or translocated. The most common fish species in lotic habitats is the Anatolian endemic Pseudophoxinus burduricus (6 stations) and in lentic habitats the invasive Carassius gibelio (7 stations). There were no seasonal differences in the abundance of fish species in the basin, which suffers from water scarcity due to inadequate water management. Statistical analyses showed that the fish fauna of the basin was shaped by its ability to tolerate the environmental conditions of the different habitats. Accordingly, while non-native species characteristic of lentic habitats were influenced by physical variables such as pH, water temperature and turbidity, the high abundance of endemic species, especially P. burduricus and Oxynoemacheilus anatolicus, in lotic ecosystems was associated with high nutrient salinity and dissolved oxygen concentrations. In conclusion, it was found that drying of rivers due to the anthropogenic stressors such as water abstraction for irrigation, fragmentation of river corridors and dam construction, and mining has caused the destruction of fish habitats, while the introduction of non-native/invasive species into the basin and changes in limnological conditions have affected the distribution of fish.