Fish Species Diversity From Someșul Cald River: 50Years After Cascade Dam Constructions

Abstract

In the present study, changes in fish species composition, distribution, and diversity caused by cascade dam constructions on Someșul Cald River, Romania, were analyzed. Cascade dam constructions may act as a freshwater stressor both on short and long term. The river was divided into two sections according to the positioning of the cascade dams (T1-inferior section, respectively T2-superior section). In the T1 and T2 sections, 8 and 12 sampling stations were established, respectively. A total number of 1789 specimens grouped in 12 species and 8 families were sampled from August to September 2018. The most abundant species in both sections was S. trutta. The most abundant family was Salmonidae, with 66.2%. Alpha diversity (species richness) in the T2 section was higher than in T1 (T2 = 12 species vs T1 = 9 species). The Kruskal-Wallis test indicated no significant differences (p > 0.05) for beta diversity of T1 vs T2 (Sørensen coefficient). The species that contributed most to the dissimilarities between the two river sections were T. thymallus, B. carpathicus, C. gobio, and S. cephalus, their summed contribution to the dissimilarity being larger than 50%. The analyzed environmental variables influenced the distribution of some fish species. Alpha and beta diversity distribution on elevation gradient showed that stations close to reservoirs had more species (both in T1 and T2 sections) than the other stations, clearly showing that the distance from lake/reservoir is influencing species richness. The effect of dams from Someșul Cald River on fish species distribution was analyzed by comparing previous data (before 1968) to recent collected data.

Spatial–temporal patterns of fish trophic guilds in a freshwater river wetland ecosystem of northeastern China

“…Regardless of the fish number, the fish species composition can undergo significant alterations. The construction of dams can introduce new species while causing the disappearance of previously documented ones due to habitat modifications (Lațiu et al., 2022 ). However, the detrimental effects of reservoir construction, such as alterations in water levels, hindrance to fish migration, and habitat fragmentation, warrant attention (Larsen et al., 2021 ; Liang et al., 2021 ; Pess et al., 2021 ).…”

The Roles Played by Environmental Sustainability and Innovation in the Rehabilitation of Abandoned Mining Sites

“…The work associated with the specific nature of mining (discovery, transport, extraction of useful minerals, storage of waste material) is highly destructive and has repercussions on the mountain habitat and local fauna. A series of negative effects with a high impact and persistence on valuable natural environments is thus produced, which makes ecosystems containing rare flora and fauna species or protected elements vulnerable [62][63][64][65][66].…”

Distribution and diversity of fishes and lampreys in Transylvania (Romania): a complete survey and suggestions for new protected areas

“…The fish fauna of some protected areas in Transylvania has been recently surveyed ( Pricope et al 2009 ; Imecs and Nagy 2012 ; Imecs et al 2014 ; Telcean et al 2014 ; Năstase and Oţel 2016 ; Năstase and Tošić 2016 ; Nagy et al 2019 ; Nagy and Imecs 2020 ), but these areas only account for a small amount of the total protected areas in Transylvania. Few other studies on smaller rivers and lakes have been published ( Battes and Pricope 2006 ; Cocan et al 2020 ; Lațiu et al 2022 ). Given the current gaps in the distribution, abundance, species identity and occurrence of native and non-native species in the Transylvanian rivers, a comprehensive and large-scale survey is necessary to support the conservation efforts of the highly diverse freshwater fish species in the region.…”