浑河流域大型底栖动物摄食功能群对栖息地环境的选择适应性

在生态系统中特定的环境变量组合对应着特定的物种群落结构。栖息地环境的不同,大型底栖动物的分布和所表现出的生物学特征也存在差异。在浑河流域选取22个点位进行调查研究,通过对大型底栖动物进行功能群分类并结合生物性状分析(BTA, Biological Traits Analysis)对浑河流域不同大型底栖动物摄食功能群对栖息地生境的选择适应性进行研究。研究结果表明:捕食者功能群主要以毛翅目为主;直接收集者功能群主要以双翅目为主;刮食者功能群主要以基眼目为主;过滤收集者多为颤蚓目。浑河流域不同大型底栖动物摄食功能群存在明显的空间差异,典范对应分析结果显示:影响捕食者功能群的驱动因子是流速,直接收集者功能群的驱动因子是IOS指数,刮者功能群的驱动因子是溶解氧;过滤收集者功能群的驱动因子是溶解氧和电导率。生物性状分析结果显示:捕食者功能群身体上附有一层硬壳保护,可在水体中自由活动,多分布流速较快,底质复杂的小鹅卵石、圆石的底质中;直接收集者只有头壳具有较厚的甲壳质壁,头部口器不能直接摄食,所以多以微粒有机颗粒为主,分布在石块、部分圆石以及部分粗砂中;刮食者多以藻类、菌类等为食,足腺多分泌粘液,多粘附在较深流速缓慢,底质多为细沙粗粒,食物来源充足的水体;过滤收集者喜栖于淤泥底质中,吸食淤泥或过滤有机碎屑,故多分布于淤泥与细沙底质中。

Selective adaptations of macrobenthic functional feeding groups in the Hunhe River basin

The combination of specific environmental variables in an ecosystem corresponds to a specific species community structure. There are also differences in the distribution of macrobenthos and their biological characteristics. In this study, 22 sites in the Hunhe River basin were selected for investigation. The functional macrobenthic feeding groups were grouped together with biological traits analysis (BTA) to identify the habitat and adaptations of different functional feeding groups in the Hunhe River basin. The results showed that spatial differences between different functional feeding groups were significant. The predator group was mainly from the order Trichinoptera, the collector-gatherers were dominated by Diptera, and the scrapers were mainly Basommatophora. Most of the collector-filterers belonged to Tubificida. Canonical correspondence analysis results showed that the driving factor affecting the predator group was the flow rate, that for the collector-gatherers was the IOS index, that for the scrapers was dissolved oxygen, and that for the collector-filterers were dissolved oxygen and conductivity. The results of the BTA showed that the predator functional group had a layer of hard-shell protection, could move freely in water, and redistribute quickly in the small pebbles and cobblestones with fast flow velocity and complex sediments. The collector-gatherers had a thicker shell. Their chitinized heads and mouthparts meant that these organisms could not feed directly, and scavenged organic particles distributed mainly in the coarse sand and on round stones. Scrapers mostly fed on algae, fungi, etc. Their foot glands secrete mucus, by which they can adhere to shore or underwater sediments. These species are found in areas with slower flow rates, with mostly fine sandy bottoms and abundant food sources. Collector-filterers like to roost in silt, sucking mud or filtering organic debris. The type of sediment is mostly silt and fine sand.