Environmental DNA captures native and non-native fish community variations across the lentic and lotic systems of a megacity

Abstract

Globally, urbanization poses a major threat to terrestrial biodiversity, yet its impact on fish diversity is poorly understood, mainly because of surveying difficulties. In this study, environmental DNA metabarcoding was used to survey fish communities at 109 lentic and lotic sites across Beijing, and how environmental variables affect fish biodiversity at fine urban spatial scales was investigated. We identified 52 native and 23 non-native taxa, with lentic and lotic waters harboring both common and habitat-specific species. Water quality strongly affected native fish diversity, especially in lentic systems, but had little influence on non-native diversity. Fish diversity showed little response to urban land cover variation, but the relative sequence abundance of non-natives in lotic waters increased linearly with distance from the city center. Our findings illustrate the complex effects of urbanization on native versus non-native fishes in different aquatic habitats and highlight the distinctive considerations needed to conserve urban aquatic biodiversity.

Fishing for fish environmental DNA: Ecological applications, methodological considerations, surveying designs, and ways forward

“…Because urban waterbodies are typically small‐sized and abundant, it can be impractical to thoroughly survey them using capture‐based methods. In a recent study by Zhang et al (2022), fish assemblages at more than 100 water sites in lentic and lotic systems across Beijing were analysed via eDNA metabarcoding and the results revealed distinct native and non‐native fish diversity patterns in response to urbanization and water quality variables. Those results highlight the power that eDNA has to resolve fine‐scale, urban aquatic biodiversity patterns.…”

Introduction of non‐native fish for aquaculture in China: A systematic review

“…215 Unregulated artificial fish propagation and release also disturbed the original community, as introduced fish are able to reproduce in the reservoir characterized by still or slow-flowing water and sufficient food sources. 216 By 2012, about 3.55 million individual larvae of 15 fish species had been released into the Three Gorges Reservoir, including the Chinese sucker Myxocyprinus asiaticus and rock carp Procypris rabaudi endemic to the upper Yangtze, Wuchang bream Megalobrama amblycephala from the lakes affiliated with the middle and low Yangtze, and pirapitinga native to the Amazon. 217 Another huge hydroproject is the South-to-North Water Diversion Project, aimed at allocating water resources across basins and regions in China.…”

“…So far, 23 non‐native species have been recorded, including 10 species introduced from America, two species from Europe, two species from Africa, and the rest from other water systems in China 215 . Unregulated artificial fish propagation and release also disturbed the original community, as introduced fish are able to reproduce in the reservoir characterized by still or slow‐flowing water and sufficient food sources 216 . By 2012, about 3.55 million individual larvae of 15 fish species had been released into the Three Gorges Reservoir, including the Chinese sucker Myxocyprinus asiaticus and rock carp Procypris rabaudi endemic to the upper Yangtze, Wuchang bream Megalobrama amblycephala from the lakes affiliated with the middle and low Yangtze, and pirapitinga native to the Amazon 217 …”

Comparative Evaluation of Common Materials as Passive Samplers of Environmental DNA

“…Environmental DNA (eDNA)-based methods have revolutionized biodiversity monitoring by enabling noninvasive, efficient, and economic surveys of diverse taxa in aquatic ecosystems. , By analyzing DNA shed from organisms into their surrounding environment in the form of skin, urine, feces, and mucus, eDNA methods bypass the need for labor-intensive and destructive capture processes and morphotaxonomic expertise. Furthermore, high-throughput sequencing and data processing can be employed, which greatly facilitates biomonitoring in terms of taxonomic range, survey scopes, and cost-effectiveness. , eDNA techniques have been increasingly embraced by ecologists and conservation biologists, and their applications have extended from detection and monitoring of a single species of interest (e.g., endangered, invasive, and commercially valuable species) − to biodiversity surveillance and ecosystem assessments. − …”