关键词: 河岸带土地利用, 鱼类群落, 多维多样性, 时空格局, 生态补水

Abstract:

[Objectives] This study aims to: (1) elucidate the spatiotemporal dynamics of fish communities and multi-dimensional diversity (species, functional, taxonomic) in ecological water supplement rivers of North China; and (2) determine the mechanistic effects of riparian land use across varying buffer sizes (0.5 km, 1 km, 2 km, 5 km) on these diversity patterns. The research focused on two major water-supplemented systems—the Ziya River Basin and Baiyangdian Lake Basin—during the ecological water supplement period from 2020 to 2022. [Methods] Field surveys were conducted annually during the water supplement period. Fishes were collected using standardized multi-mesh gillnets and traps, identified to species level, and quantified for abundance and biomass. Species functional traits (feeding, locomotion, predator avoidance, trophic level, reproduction) were compiled following Villéger et al., primarily sourced from FishBase and literature. Taxonomic diversity metrics were calculated based on Linnaean hierarchies (species to class). Riparian land use types (built area, wetland, trees, crop, water, bare ground, and rangeland) within four buffer zones (0.5 km, 1 km, 2 km, 5 km) were extracted from ESRI’s global 10-m resolution land cover data. Statistical analyses included: Analysis of Variance (ANOVA) and Permutational Multivariate Analysis of Variance (PERMANOVA) to test interannual differences; Non-metric Multidimensional Scaling (NMDS) to visualize community structure; Pearson correlation analysis to examine relationships among diversity indices; and Multiple Linear Regression (MLR) models to quantify the driving effects of riparian land use on fish diversity. [Results] A total of 2,720 fish individuals, belonging to 40 species, 12 families across 6 orders, were recorded during the three-year field survey. Species richness (26 species in 2020, 27 in 2021, 26 in 2022; ANOVA, p>0.05) and diversity indices (Shannon, Margalef, Pielou) showed no significant interannual changes. However, significant shifts in species composition were observed: rheophilic, clean-water indicator species (e.g., Opsariichthys bidens, Zacco platypus) increased in relative abundance from 7.3% (2020) to 12.6% (2022), while pollution-tolerant generalists (e.g., Carassius auratus) remained dominant but declined from 22.38% to 17.14%. NMDS and PERMANOVA confirmed no significant interannual differences in overall community structure. Multi-dimensional diversity indices (functional:FRic,FDiv,FDis,FEve;taxonomic: Delta, Delta*, Delta+, Lambda+) also exhibited no significant temporal trends. Pearson correlations revealed strong positive relationships among species diversity indices (e.g., Richness vs. Shannon: r=0.91) and showed that functional dispersion (FDis) was significantly positively correlated with all diversity dimensions (r=0.32-0.64). Built area exerted significant negative effects on most diversity indices. Wetland, rangeland, and water positively correlated with diversity. Buffer size significantly influenced explanatory rate: Riparian land use explained 7.3% to 28.3% of the variation in diversity indices. Effects were strongest on functional and species diversity within smaller buffers (0.5-1 km; e.g., 28.3% explanation for Shannon within 0.5 km buffer), >2 km buffers, cropland and bare ground significantly reduced functional diversity (FRic and FDiv; p<0.05), while larger buffers (5 km) showed higher explanatory power for taxonomic diversity metrics (11.9% explanation for Delta). Functional dispersion (FDis) and taxonomic diversity (Delta) correlating significantly with all diversity dimensions (r=0.36-0.90; p<0.05) and outperforming species richness in detecting environmental responses. [Conclusions] Although overall diversity metrics showed no significant changes, the increase in sensitive rheophilic fish species indicates improved water quality following ecological water supplementation. Riparian land use, particularly built area expansion, significantly reduced multi-dimensional fish diversity, whereas wetlands, rangeland, and water enhanced it. Land use impacts exhibited scale dependence: near-shore buffers (0.5-1 km) dominated functional and species diversity changes, while larger-scale land use (5 km) primarily influenced taxonomic diversity. This underscores the need for scale-targeted management measures. Furthermore, functional dispersion (FDis) and taxonomic diversity (Delta) proved more sensitive indicators of community changes than species richness alone, recommending their integration into future monitoring frameworks. These findings provide a scientific basis for prioritizing conservation targets and formulating management strategies in water-supplemented river restoration.

Key words: riparian land use, fish community, multi-dimensional diversity, spatiotemporal patterns, ecological water supplement