Doherty-Bone Thomas M, Dunn Alison M, Liddell Caroline, Brown Lee E
1School of Biology, University of Leeds, Leeds, West Yorkshire UK.
2School of Geography, University of Leeds, Leeds, West Yorkshire UK.
Biol Invasions. 2018;20(7):1799-1808. doi: 10.1007/s10530-018-1661-z. Epub 2018 Jan 31.
Invasive alien species have the potential to alter biodiversity and ecosystem processes. In freshwaters, detritus decomposition is a major ecosystem service but it remains uncertain whether invasive alien decapods process detritus differently to natives. This study examined leaf litter processing, and cascading effects on biofilms, by the European native white clawed crayfish () compared to two invasive alien decapod species: the American signal crayfish () and the Chinese mitten crab (). Invasive alien decapods were responsible for higher leaf litter decomposition than the native. In comparison with native crayfish, invasive alien crab and crayfish showed higher rates of litter consumption, increased production of smaller leaf fragments, fine particulate organic matter (FPOM) and dissolved organic carbon. Nutrients (ammonia and soluble reactive phosphorous) derived from excretion (measured separately in the absence of biofilms) varied among decapod species, being lower for However, nutrient concentrations did not vary among species in the detritivory experiments with biofilm, implying nutrients were utilised for biofilm production and respiration as no differences in biomass were evident among decapod treatments. These results show invasive alien decapods have the potential to increase the magnitude of detrital processing to FPOM in rivers, but indirect impacts on primary producers due to nutrient release are uncertain based on this experimental context.
外来入侵物种有可能改变生物多样性和生态系统过程。在淡水环境中，碎屑分解是一项主要的生态系统服务，但外来入侵十足目动物处理碎屑的方式是否与本地物种不同仍不确定。本研究比较了欧洲本土的白爪螯虾（）与两种外来入侵十足目物种：美国信号螯虾（）和中华绒螯蟹（）对落叶的处理以及对生物膜的级联效应。外来入侵十足目动物比本地物种导致更高的落叶分解率。与本地螯虾相比，外来入侵蟹和螯虾表现出更高的落叶消耗率，产生更小的叶片碎片、细颗粒有机物质（FPOM）和溶解有机碳的量增加。排泄产生的营养物质（氨和可溶性活性磷，在没有生物膜的情况下单独测量）在十足目物种之间有所不同，对于而言较低，但在有生物膜的碎屑食性实验中营养物质浓度在物种之间没有差异，这意味着营养物质被用于生物膜生产和呼吸，因为在十足目处理之间生物量没有明显差异。这些结果表明外来入侵十足目动物有可能增加河流中碎屑加工为FPOM的程度，但基于此实验背景，由于营养物质释放对初级生产者的间接影响尚不确定。
