Wei Hui, Liang Yanting, Luo Qiang, Gu Dangen, Mu Xidong, Hu Yinchang
Key Laboratory of Prevention and Control for Aquatic Invasive Alien Species (Ministry of Agriculture and Rural Affairs), Key Laboratory of Alien Species and Ecological Security (CAFS) Pearl River Fisheries Research Institute, Chinese Academy of Fisheries Science Guangzhou Guangdong China.
School of Marine Sciences Guangxi University Nanning Guangxi China.
Ecol Evol. 2022 Nov 5;12(11):e9483. doi: 10.1002/ece3.9483. eCollection 2022 Nov.
Intraspecific variation in stoichiometric traits was thought to be an adaptive response to reduce the elemental imbalance between organism and diet in the habitat. Studying the spatial variation of stoichiometric traits of non-native species and the factors contributing to the variation could help to better understand the invasion mechanism of non-native fish. In this study, stoichiometric traits (i.e. carbon [C], phosphorus [P], calcium [Ca] and their ratios) variation in the body and organs of non-native sailfin catfishes spp. were investigated across 13 river sections in the main river basins of Guangdong province. The relationships between environmental factors and stoichiometric traits were analyzed using a general linear model and an information-theoretic approach. A manipulated feeding experiment was conducted to investigate the impact of food quality on the stoichiometry of sailfin catfishes in a greenhouse. Sailfin catfishes exhibited considerable variability in body and organ elemental composition. Site identity was the main factor contributing to the variation, which could be explained by a combination of environmental factors including climate, diet quality, fish species richness and trophic status in the invaded rivers. Water chemistry (i.e. total nitrogen and phosphorus, ammonia nitrogen and soluble reactive phosphorus) contributed to the most variation of stoichiometric traits. Imbalances of P and Ca between sailfin catfishes and food resources varied among sampling sites, reflecting the spatial heterogeneity of nutrients limitation. Juvenile sailfin catfishes exhibited stoichiometric homeostasis (0 < 1/H < 0.25) for all elemental contents and ratios in the feeding experiment. These findings suggested variation in stoichiometric traits of sailfin catfishes might be attributed to the changes in elemental metabolism to cope with context-specific environments. This study provided heuristic knowledge about environmental-related variation in stoichiometric traits, which could enhance the understanding of the non-native species' adaptation to resource fluctuation in the invaded ecosystems.
化学计量特征的种内变异被认为是一种适应性反应，以减少栖息地中生物体与食物之间的元素不平衡。研究非本地物种化学计量特征的空间变异及其影响因素，有助于更好地理解非本地鱼类的入侵机制。本研究调查了广东省主要流域13个河段的外来物种苏氏圆腹[鱼芒]身体和器官的化学计量特征（即碳[C]、磷[P]、钙[Ca]及其比率）变异。使用一般线性模型和信息论方法分析了环境因素与化学计量特征之间的关系。在温室中进行了人工投喂实验，以研究食物质量对苏氏圆腹[鱼芒]化学计量的影响。苏氏圆腹[鱼芒]在身体和器官元素组成上表现出相当大的变异性。地点是造成变异的主要因素，这可以由包括气候、食物质量、鱼类物种丰富度和入侵河流的营养状态等环境因素的组合来解释。水化学（即总氮和磷、氨氮和可溶性活性磷）对化学计量特征的变异贡献最大。苏氏圆腹[鱼芒]与食物资源之间的P和Ca失衡在不同采样地点有所不同，反映了养分限制的空间异质性。在投喂实验中，苏氏圆腹[鱼芒]幼鱼对所有元素含量和比率都表现出化学计量稳态（0 < 1/H < 0.25）。这些发现表明，苏氏圆腹[鱼芒]化学计量特征的变异可能归因于元素代谢的变化，以应对特定环境。本研究提供了关于化学计量特征与环境相关变异的启发性知识，这可以增强对非本地物种在入侵生态系统中对资源波动适应的理解。
