Almeida Alexandre M, Souza Ricardo M
Nematology Research Group, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Brazil.
J Nematol. 2020 Nov 24;52. doi: 10.21307/jofnem-2020-100. eCollection 2020.
The term phytotelma (pl. phytotelmata) designates a plant-associated reservoir of fresh water and organic debris. Phytotelmata in tank bromeliads are abundant in tropical forests, and they provide shelter, food, and water for many metazoans. Among the invertebrates known to inhabit phytotelmata, nematodes are the least studied, despite their important role in nutrient and energy cycles in freshwater ecosystems. This study was conceived to characterize the nematode trophic structure in the phytotelma of the bromeliad , and to identify climate and microenvironmental variables that impact it. Nematode abundance (total and per trophic group), rainfall, air temperature, the amount of organic debris fallen into the phytotelma, and eight physico-chemical properties (PCPs) of the water retained in the bromeliad tank - volume; temperature; pH; dissolved organic carbon, nitrogen, oxygen, and solids; and electrical conductivity - were monitored during two years in a natural reserve in Brazil. Bacterial and hyphal feeder nematodes predominated over other trophic groups. Nematode abundance (total and per trophic group) was not impacted by fluctuations in rainfall or air temperature. The amount of organic debris fallen into the phytotelma correlated positively with nematode abundance (total and per trophic group). Regarding the PCPs of water, the only significant correlation - positive - was between the amount of dissolved oxygen and the abundance of hyphal feeder nematodes. These results bring a clearer understanding of the ecology of nematodes inhabiting phytotelmata, which are peculiar and understudied freshwater ecosystems.
“附生植物积水处”（复数形式为phytotelmata）指的是与植物相关的淡水和有机残骸蓄积处。凤梨科植物叶腋积水处在热带森林中很常见，它们为许多后生动物提供庇护所、食物和水。在已知栖息于附生植物积水处的无脊椎动物中，线虫是研究最少的，尽管它们在淡水生态系统的养分和能量循环中发挥着重要作用。本研究旨在描述凤梨科植物积水处线虫的营养结构，并确定影响其的气候和微环境变量。在巴西的一个自然保护区内，对线虫丰度（总数及各营养类群）、降雨量、气温、落入附生植物积水处的有机残骸量以及凤梨科植物叶腋积水处留存水的八项理化性质（体积、温度、pH值、溶解有机碳、氮、氧和固体以及电导率）进行了为期两年的监测。细菌取食线虫和真菌取食线虫在其他营养类群中占主导地位。线虫丰度（总数及各营养类群）不受降雨或气温波动的影响。落入附生植物积水处的有机残骸量与线虫丰度（总数及各营养类群）呈正相关。关于水的理化性质，唯一显著的正相关是溶解氧量与真菌取食线虫丰度之间的关系。这些结果使人们对栖息于附生植物积水处的线虫生态学有了更清晰的认识，附生植物积水处是独特且研究不足的淡水生态系统。
