Department of Biology, Graduate Program in Ecology of Inland Waters, Nupelia, University of Maringá, Jd. Universitário, Maringá, PR 87020-900, Brazil.
Department of Biology, Graduate Program in Ecology of Inland Waters, Nupelia, University of Maringá, Jd. Universitário, Maringá, PR 87020-900, Brazil.
Sci Total Environ. 2021 May 15;769:144524. doi: 10.1016/j.scitotenv.2020.144524. Epub 2021 Jan 14.
Non-native species are considered a major global threat to biodiversity, and their expansion to new ecosystems has recently increased. However, the effect of non-native species on ecosystem functioning is poorly understood, especially in hyperdiverse tropical ecosystems of which long-term studies are scarce. We analyzed the relationship between richness, biomass, and β-diversity of non-native and native fishes during 16 years in five hyperdiverse tropical shallow lakes. We further elucidated how an observed increase in the proportion of richness, biomass, and β-diversity of non-native over native fishes affect crucial multifunctional processes of lakes (decomposition, productivity). We found a general positive relationship between the richness and biomass of non-native and native fishes. However, the slope of this relationship decreased continuously with time, displaying an increase in non-native species richness and a decrease in native species richness over time. We also detected a negative relationship between the β-diversity of non-native and native fishes over time. Moreover, the increase in the non-native:native ratio of species richness, biomass, and β-diversity over time decreased ecosystem multifunctionality. Our results suggest that non-native fishes caused a homogenization of the native fish species over time, resulting in impoverishment of ecosystem multifunctionality; in part because non-native fishes are less productive than native ones. Therefore, focus on long-term effects and use of multiple biodiversity facets (α- and β-diversity) are crucial to make reliable predictions of the effects of non-native fish species on native fishes and ecosystem functioning.
非本地物种被认为是对生物多样性的主要全球性威胁，它们向新生态系统的扩张最近有所增加。然而，非本地物种对生态系统功能的影响还了解甚少，特别是在生物多样性极高的热带生态系统中，长期研究非常匮乏。我们分析了在五个高度多样化的热带浅湖中，16 年间非本地和本地鱼类丰富度、生物量和β多样性之间的关系。我们进一步阐明了非本地鱼类丰富度、生物量和β多样性相对于本地鱼类的比例增加如何影响湖泊的关键多功能过程（分解、生产力）。我们发现非本地和本地鱼类的丰富度和生物量之间存在一般的正相关关系。然而，这种关系的斜率随着时间的推移连续下降，表现为非本地物种丰富度增加，本地物种丰富度随时间减少。我们还检测到非本地和本地鱼类之间的β多样性随时间呈负相关关系。此外，非本地物种相对于本地物种的丰富度、生物量和β多样性的比值随时间增加，导致生态系统多功能性降低。我们的结果表明，非本地鱼类随着时间的推移导致本地鱼类物种同质化，从而导致生态系统多功能性的减少；部分原因是非本地鱼类的生产力低于本地鱼类。因此，关注长期效应和使用多种生物多样性方面（α和β多样性）对于可靠预测非本地鱼类物种对本地鱼类和生态系统功能的影响至关重要。
