ICAR-Central Coastal Agricultural Research Institute (CCARI), Ella, Old Goa, Goa, 403 402, India.
ICAR-Central Institute of Fisheries Education, Mumbai, 400 061, India.
Environ Sci Pollut Res Int. 2022 Aug;29(38):58278-58296. doi: 10.1007/s11356-022-19794-8. Epub 2022 Apr 2.
Invasive alien species (IAS) influence the trophic organisation and food web structure in an invaded ecosystem, and therefore, it is imperative to quantify the resultant ecological impacts. The globally recognised ecosystem modelling platform, Ecopath with Ecosim, was used to delineate the impacts of IAS on a tropical freshwater pond ecosystem in India. We analysed the trophic interactions, consumption patterns, prey overlap and mixed trophic impacts of three co-existing invasive alien fish species, African catfish (Clarias gariepinus), suckermouth catfish (Pterygoplichthys pardalis) and Mozambique tilapia (Oreochromis mossambicus), on other functional groups in the ecosystem. Together, the three IAS shared 11% of the total energy consumption and about 50% of the energy consumption by the fish species/groups. There was no predation mortality for African catfish and suckermouth catfish, and a very low estimate for the same was recorded for tilapia (0.64 year). The IAS shared high mean prey overlap with the native fish groups (Garra sp., Etroplus suratensis, Systomus sarana, Chanda nama and various small species of the cypriniform genera Puntius, Rasbora and Devario) indicating a substantial competition between alien and native species in the ecosystem. Consequently, the three IAS exhibited higher mean negative mixed trophic impacts on these functional groups. A very high Finn's cycling index (39.59%), a low relative ascendency (28.5%) and a very low system robustness (0.07) were observed compared to similar ecosystems, and the baseline values. These indices exposed the vulnerability of the ecosystem towards perturbations, which could be due to the presence of multiple alien invasive species. Mitigating the impacts of IAS should involve a combination of approaches, including eradication through draining and harvesting, high-density stocking of similar trophic level fish in the pond, and local and national level policy interventions.
入侵的外来物种（IAS）会影响入侵生态系统中的营养组织和食物网结构，因此，量化由此产生的生态影响是当务之急。我们使用全球公认的生态系统建模平台 Ecopath with Ecosim 来描绘三种共存的入侵外来鱼类（非洲鲶鱼 Clarias gariepinus、吸盘鲶鱼 Pterygoplichthys pardalis 和莫桑比克罗非鱼 Oreochromis mossambicus）对印度热带淡水池塘生态系统的影响。我们分析了生态系统中其他功能群的营养相互作用、消费模式、猎物重叠和混合营养影响。这三种入侵外来物种共消耗了总能量的 11%，鱼类物种/群体消耗的能量约为 50%。非洲鲶鱼和吸盘鲶鱼没有捕食死亡率，罗非鱼的捕食死亡率非常低（0.64 年）。IAS 与本地鱼类群体（Garra sp.、Etroplus suratensis、Systomus sarana、Chanda nama 和各种小型鲤科鱼类 Puntius、Rasbora 和 Devario）的平均猎物重叠率很高，表明在生态系统中，外来物种与本地物种之间存在大量竞争。因此，这三种 IAS 对这些功能群表现出更高的平均负混合营养影响。与类似的生态系统和基线值相比，观察到非常高的芬氏循环指数（39.59%）、相对优势度（28.5%）和非常低的系统稳健性（0.07）。这些指数暴露了生态系统对扰动的脆弱性，这可能是由于存在多种外来入侵物种。减轻 IAS 的影响应该包括多种方法的结合，包括通过排水和收获进行根除、在池塘中高密度放养类似营养级别的鱼类，以及地方和国家层面的政策干预。
