Positive Correlation Between Economic Activities and Fish Diversity in Small River Basins of Less Developed Regions: A Case Study of the Lixian River Basin
by
, and
Rong Huang
1,
Bolin Chen
1,
Chengcheng Ma
1,
Chao Deng
1,
Jiaqi Zhang
1,
Zhihui Xiao
1,
Zhijian Wang
1,2,
Yaqiu Liu
3,* and
Xiaohong Liu
1,* 1
Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing 400715, China
2
School of Agronomy, Xinjiang Hetian College, Xinjiang 848000, China
3
Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
*
Authors to whom correspondence should be addressed.
Animals 2025, 15(16), 2416; https://doi.org/10.3390/ani15162416
Submission received: 11 July 2025
/
Revised: 7 August 2025
/
Accepted: 15 August 2025
/
Published: 18 August 2025
(This article belongs to the Section Aquatic Animals)
Simple Summary
Economic activities have a significant impact on the aquatic environment, including fish. In this study, we employed environmental DNA (eDNA) technology to conduct surveys in the Lixian River basin, where economic development exhibits a gradient pattern. The results indicated that fish communities showed an obvious gradient variation from the upstream to the downstream reaches. Surprisingly, we found significant positive correlations between agricultural population, total grain production, total population, and the diversity index. This suggests that in less economically developed regions, the development of local economic activities may enhance fish diversity, revealing a potential synergistic relationship between economic activities and fish diversity in small-scale river basins and providing a new perspective for understanding economic–ecological interactions.
Abstract
(1) Background: Affected by multiple factors, the decline in fish species diversity in some aquatic ecosystems has become increasingly pronounced. At a broad spatial scale, economic development has been widely recognized as one of the key factors influencing the fish distribution pattern. However, at a small scale, within a single river basin, the effects of economic development on the freshwater fish distribution and communities remain largely uninvestigated. (2) Methods: environmental DNA (eDNA) samples were collected from 26 sampling sites of the Lixian River in both the summer (June) and winter (November). Economic data from the Lixian River basin were collected, and analyses, including multivariate regression tree analysis and generalized linear model fitting, were performed using R 4.3.2. (3) Results: A total of 65 fish species was characterized, and the Chao1 diversity indices in the upstream (13.42) and downstream (13.00) were significantly higher than those in the middle reaches (8.55, p < 0.01) of this river. The species communities exhibited an obvious gradient changing pattern from the upstream to the downstream reaches, with parameters of water quality, including transparency, pH, dissolved oxygen and temperature, and climatic factors functioning as the key variables. Furthermore, the generalized linear model analysis revealed significant positive correlations between agricultural population (p = 0.00106), total grain production (p = 0.00476), total population (p = 0.00192) and the Chao1 index. (4) Conclusions: Climatic factors are the key factors affecting the fish diversity in the Lixian River. In less economically developed areas, the development of local economic activities may enhance fish diversity.
Keywords:
fish diversity; environmental DNA; economic development
