Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile.
Amnis Opes Institute, Oregon, USA.
Neotrop Entomol. 2021 Dec;50(6):873-885. doi: 10.1007/s13744-021-00900-3. Epub 2021 Aug 30.
Macroinvertebrates from a small forest stream in central-south Chile were sampled monthly from September 2017 to August 2018 to assess temporal variability in the assemblage and the effects of that variability on ecological indicators. Higher precipitation and flows occurred in winter months, and water quality varied among months. We collected 59 macroinvertebrate taxa, finding higher taxa richness and abundances in summer months than in winter months. Four taxa demonstrated marked seasonality, being abundant in some months and then decreasing in following months (Limnoperla jaffueli (Navás), Nousia maculata (Demoulin), Smicridea sp. (McLachlan), Chironomidae spp.). The scores of the family Hilsenhoff Biotic Index (HBI), Hilsenhoff Species-level Biotic Index (HSBI), Multimetric Macroinvertebrate Index (MMI), and Chilean Biological Monitoring Working Party (ChBMWP) index varied throughout the year reflecting natural variability. However, only HBI and HSBI scores were significantly different among seasons, ranging across three water quality classes (excellent, very good, and good), showing the lowest water classes in spring, coinciding with higher abundances of tolerant species. The MMI and ChBMWP indicated good and very good site conditions throughout the year, respectively. Shannon-Weaver diversity ranged between 2.59 (April) and 1.78 (February); however, Pielou evenness had high values throughout the year (> 0.62), except in February. Changes in macroinvertebrates composition throughout the year were explained primarily by discharge, water temperature, and conductivity. Our findings indicate that natural monthly variability in macroinvertebrate assemblages influences the scores of biological indices throughout the year. Therefore, we recommend that natural stream variability be accounted for in biomonitoring programs. We also emphasize the need to use caution when interpreting biological index scores to avoid misinterpretations in stream quality classification.
2017 年 9 月至 2018 年 8 月，每月从智利中南部的一条小溪中采集大型无脊椎动物样本，以评估群落的时间变异性及其对生态指标的影响。冬季降水和水流较高，水质在各月份之间有所变化。我们共采集到 59 种大型无脊椎动物，发现夏季的高等分类群丰富度和丰度高于冬季。有 4 个分类群表现出明显的季节性，在某些月份大量出现，然后在随后的月份减少（Limnoperla jaffueli (Navás)、Nousia maculata (Demoulin)、Smicridea sp. (McLachlan)、Chironomidae spp.）。家庭 Hilsenhoff 生物指数（HBI）、Hilsenhoff 种级生物指数（HSBI）、多指标大型无脊椎动物指数（MMI）和智利生物监测工作组（ChBMWP）指数的得分全年都在变化，反映了自然变异性。然而，只有 HBI 和 HSBI 得分在季节之间存在显著差异，范围跨越三个水质类别（优秀、很好和良好），春季的水质类别最低，这与耐受物种的丰度较高有关。MMI 和 ChBMWP 指数分别在全年表示良好和很好的站点条件。香农-威纳多样性在 2.59（4 月）和 1.78（2 月）之间变化；然而，除了 2 月，皮埃罗均匀度在全年都保持较高值（>0.62）。全年大型无脊椎动物群落组成的变化主要由流量、水温、电导率解释。我们的研究结果表明，大型无脊椎动物群落的自然月度变化会影响全年生物指数的得分。因此，我们建议在生物监测计划中考虑自然溪流的变异性。我们还强调，在解释生物指数得分时需要谨慎，以避免对溪流质量分类的误解。
