Abstract

The species composition and abundance of zoobenthos are studied to reveal the structure of bottom invertebrate communities under the effect of biotopical, hydrological, and climatic factors. One hundred and six quantitative samples were collected from 15 pools of rapid rivers (61.6°–67.1° N) from 2003 to 2017 in eastern Fennoscandia. The basic part of the fauna is formed by 151 species, including 36 Diptera species, 23 Trichoptera species, 21 Bivalvia species, and 19 Ephemeroptera species. Representatives of Chironomidae, Oligochaeta, Sphaeriidae, Ephemeroptera, and Trichoptera occurred most frequently in the samples (89, 72, 58, 40, and 28%, respectively). The diversity of bottom communities of the pools was low when compared to that in the riffles. The abundance of zoobenthos varies greatly from site to site (from 0.06 to 42.6 thousand spec./m² and from 0.06 to 100.8 g/m²). The average values ​​(3106 ± 642 spec./m² and 6.6 ± 1.27 g/m²) are comparable with the abundance of zoobenthos in the riffles. The basic biomass was formed by Bivalvia (Euglesa spp.), Gastropoda (Radix intermedia and Gyraulus borealis), Diptera (Chironominae spp. and Dicranota bimaculata), and Trichoptera (Brachycentrus subnubilus and Hydropsyche contubernalis borealis). The lowest zoobenthos biomass was detected in brooks (1.4 ± 0.37 g/m²) and the highest was in the medial zone of rivers (9.5 ± 2.52 g/m²). Local aggregations of large mollusks (Anodonta cygnea, Unio pictorum, and U. tumidus) with a multiple biomass (0.5–3.6 kg/m²) and a density of 80–120 spec./m²) were found in the study area (4% of samples, mainly in the medial zone). Gatherer–collectors were dominant in the trophic structure (32–60% of biomass); the proportions of groups varied depending on the characteristics of the biotope, in particular, the pattern of the bottom substrate. An increase in the zoobenthos biomass was recorded in the southern part of the region: from 2.7 ± 0.48 g/m² north of 65° N to 8.6 ± 1.82 g/m² south of 63° N. Comparison of the structure of the zoobenthos of rapid river pools in Fennoscandia with that in lowland rivers in other areas did not reveal any fundamental differences, which indicates the importance of local hydrological and other factors in the formation of the composition and abundance of bottom invertebrate communities.

中文翻译：

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急流河池的底栖动物：组成，丰度和营养结构（基于东部芬诺斯堪的亚的例子）

摘要

研究了底栖动物的种类组成和丰富度，以揭示在生物位，水文和气候因素的影响下底无脊椎动物群落的结构。从2003年至2017年，在芬诺斯坎迪亚东部的15条快速河（61.6°至67.1°N）的河流池中收集了一百六十份定量样本。该动物群的基本部分由151种组成，其中包括36种双翅类，23种直翅类，21种双壳纲和19种星翅类。Chironomidae，Oligochaeta，Sphaeriidae，Ephemeroptera和Trichoptera的代表在样品中出现频率最高（分别为89％，72％，58％，40％和28％）。与浅滩相比，池底群落的多样性较低。各地的游动底栖动物的丰度差异很大（从0.06到4.26万规格/米²和0.06至100.8 g / m ²）。平均值（3106±642 spec./m ²和6.6±1.27 g / m ²）可与浅滩中的底栖动物的丰度相媲美。基本生物量由双壳纲（Euglesa spp。），腹足纲（Radix intermedia和Gyraulusborealis），双翅目（Ciminominae spp。和Dicranota bimaculata）和毛翅目（Trichoptera）（Brachycentrus subnubilus和Hydropsyche contubernalis northalis）形成。溪流中底栖动物的生物量最低（1.4±0.37 g / m ²），最高的是河流中部地区（9.5±2.52 g / m ^2））。在研究区域内发现了大型软体动物（Anodonta cygnea，Unio pictorum和U. tumidus）的局部聚集体，其中有多种生物量（0.5–3.6 kg / m ²），密度为80–120 spec./m ^2。 4％的样本，主要在内侧区域）。收集者-收集者在营养结构中占主导地位（占生物量的32-60％）。基团的比例根据生物群落的特征，特别是底部基底的图案而变化。在该区域的南部记录到底栖动物的生物量增加：从65°N以北的2.7±0.48 g / m ²增至8.6±1.82 g / m ² 南北63°。Fennoscandia的快速河塘的底栖动物的结构与其他地区的低地河流的底栖动物的结构的比较没有发现任何根本性的差异，这表明了当地水文和其他因素在组成中的重要性底层无脊椎动物群落丰富。