Conservation value of rivers under climate change: a case study from Fars Province, Iran

The unprecedented rates of warming observed in recent decades are recognized as a major environmental issue. As a source of extreme and unpredictable environmental variation on a global scale, climate change stands as one of the most significant threats to freshwater biodiversity. Southwestern Iran, particularly Fars province, is recognized as one of Iran's biological diversity hotspots and is critically important for aquatic biodiversity. However, this biodiversity faces numerous pressures, and climate change has added significant strain over the past two decades. In this pilot study, we assessed the impact of climate change on 26 fish species in the region using a species distribution model. Current potential habitats were modeled using the maximum entropy algorithm, and the results were projected into the future (i.e., the years 2050 and 2080) under two climatic scenarios: optimistic and pessimistic (i.e., Representative Concentration Pathways 4.5 and 8.5) for each year. Finally, we mapped the rivers with the highest fish species richness and projected their potential shifts in the future. The modeling performance for the species was valid, with the AUC of the Receiver Operating Characteristic curve being greater than 0.7. Species reacted to climate change scenarios differently. Some species are likely to gain new suitable habitats, while others may be adversely affected, losing parts of their potential habitats. In addition, the results highlighted fish hotspots in the studied region will probably shift to other parts of the province showing the dire need for conservation. These findings provide essential information for conservationists, facilitating the development of effective conservation strategies.