流溪河底栖硅藻群落结构的时空异质性及其影响因素

底栖硅藻能够较好地响应河流水环境变化,其群落物种组成与分布已被广泛应用于河流水质与生态状况的指示与评估。为了解流溪河底栖硅藻群落结构的时空异质性及其受河流水文与水质的影响,从上游到下游共设置了 20个样点,于2018年3月、6月、9月和12月进行季节采样和观测,采集底栖硅藻,同步测定了水体理化因子;在分析群落组成的基础上,进一步探究河流环境变量和空间变量对流溪河底栖硅藻群落的影响。结果表明,4次调查共检 出底栖硅藻276种,隶属于2纲、6目、9科、55属,底栖硅藻多样性具有明显的时空差异。在季节上,丰水期的物种丰 富度和真辛普森多样性指数高于枯水期。枯水期曲壳藻科的相对丰度超过50%,高于丰水期;而舟形藻科在丰水期 时相对丰度比枯水期高。在空间上,三级河流物种多样性最高,一级河流物种多样最低;一级河流和二级河流的优 势种主要以曲丝藻属的种类为主,三级河流的优势种主要以菱形藻属的种类为主。随着河流等级增加,曲壳藻科相 对丰度降低,而菱形藻科的相对丰度逐渐升高。冗余分析（RDA）表明,环境选择和空间要素对流溪河硅藻群落结构 均有显著影响,但营养盐水平比空间要素有更高的解释率。     

Response of biota to aeration rate in low water exchange ponds farming white shrimp, Penaeus vannamei Boone

The response of phytoplankton, zooplankton and benthos to four aeration rates was evaluated in ponds farming white shrimp, Penaeus vannamei Boone, with less than 5% water exchange. Phytoplankton biomass (measured as chlorophyll-fl) was higher in ponds with aeration rates of 0 and 6 h day^?1 than in those with rates of 24 hday^?1. The abundance of zooplankton and benthos (organisms m^?2) were higher in ponds with aeration rates of 0 and 6 h day^?1, and lower in ponds with rates of 12 and 24 h day^?1. The nauplii of different crustaceans, copepods and larval polychaetes were the most abundant organisms of the zooplankton community. Differences in zooplankton composition were observed among treatments. Polychaetes were the most abundant benthic organisms during the culture period. These organisms were more abundant in ponds with lower aeration rates. The guts of shrimp from ponds with aeration rates of 0 and 6 h day^?1 had a higher abundance of zooplankton and benthic organisms than those from the other treatments. That abundance decreased over time in all treatments. Shrimp had better growth in ponds with an aeration of 6 hday^?1. Survival and yield were similar in ponds with aeration rates of 6, 12 and 24 h day^?1, and lower in ponds with rates of 0 h day^?1.     

Effects of organic effluents from a salmon farm on a fjord system. II. Temporal and spatial patterns in infauna community composition

This study examined spatial and temporal variations in infaunal community composition in a gradient away from a large salmon farm (producing 2910 tonnes during each production cycle) in Uggdalsfjorden, western Norway. The farm is located at a water depth of 230 m, is moored at a single point and moves with prevailing currents and winds. The study showed that the large-scale effects on the benthos were restricted to the nearest 250 m of the farm. This zone was dominated by the polychaetes Paramphinome jeffreysii, Prionospio steenstrupi, Capitella capitata and Heteromastus filiformis, the bivalves Thyasira sarsii and Abra nitida and the echinoderm Brissopsis lyrifera for the duration of the two-year study. Highest abundance and biomass were recorded at peak production at the farm, with 30 000 individuals m^− 2 and 60 g ash-free dry weight (AFDW) m^− 2. At this time abundance was 10 and biomass was 35 times higher within 250 m from the farm than 3 km away. Highest species richness was found 550–900 m from the farm, where, at peak production, the number of species doubled from 20 to 40 species per 0.1 m^− 2. The study showed that at deep sites organic waste affects benthos on a spatial scale much larger than at shallow water sites, and although the infauna community composition varied over time, the consistency in the spatial pattern in the relationship between species richness, abundance and biomass in the course of the study indicates that the observed patterns were temporally stable. The loadings of organic matter from the farm did not exceed the capacity of the benthic community for decomposition, as indicated by the low and stable content of organic matter in the sediment around the farm.     

曹妃甸近岸海域大型底栖动物群落特征

基于2015年9月和2016年5月采集的曹妃甸近岸海域的大型底栖动物数据,对该海域大型底栖动物的种类组成和群落结构等进行研究,利用丰度/生物量比较曲线法、AMBI指数法和M-AMBI指数法对研究海域大型底栖动物群落健康和生境质量进行评价。研究结果表明,2015年9月和2016年5月共采集到大型底栖动物73种,其中节肢动物和环节动物物种数占据较大比例。该海域的优势种为日本大螯蜚、日本刺沙蚕、囊叶齿吻沙蚕、轮双眼钩虾,其中日本大螯蜚具有最大的丰度和优势度。群落结构聚类分析和多维尺度分析表明,2015年9月研究区域的大型底栖动物群落以20%的相似性可以分为4组,2016年5月以10%的相似性可以分为7组,两次调查的群落结构相似性均较低。丰度/生物量比较曲线法研究结果显示,2015年9月底栖群落受到严重污染扰动,而到2016年5月,底栖动物群落生物量优势显著上升,群落受扰动状况改善,达到未受或受到轻微污染扰动状态。AMBI指数及M-AMBI指数法评价结果表明,曹妃甸海域大部分站位生境质量为良好状态。本研究揭示了曹妃甸近岸海域大型底栖动物群落结构特征,可为该海域生态环境保护提供依据。     

基于大型底栖动物的桑沟湾不同养殖区底栖生境健康评价

为了解桑沟湾养殖区大型底栖动物的动态变化以及底栖生境的健康状况,于2019年5-9月采集了中国北方典型养殖海湾桑沟湾不同养殖区（藻类、贝类和网箱养殖区）大型底栖动物样品,分析了不同养殖区大型底栖动物的种类、组成、数量分布、群落结构及生物多样性等群落特征,运用多样性指数、AMBI和M-AMBI指数法评价了不同养殖区底栖生境健康状况的时空变化。调查共鉴定出大型底栖动物56种,其中多毛类31种,甲壳类10种,软体动物9种,棘皮动物4种,其他类2种,大型底栖动物的优势种主要为多毛类,以污染耐受种为主;调查期间,贝类养殖区和网箱养殖区的群落多样性指数H''呈现下降趋势,表明贝类养殖活动和网箱养殖活动已经造成沉积物中有机物颗粒过度积累。ABC曲线显示,7月桑沟湾养殖区开始受到干扰,8月和9月受到中等程度的干扰。AMBI和M-AMBI指数评价显示桑沟湾养殖区域底栖生态系统处于轻度或中度干扰状态,底栖生境健康状况处于高等或者良好的状态。     

三沙湾夏季大型底栖动物群落结构及其和水产养殖活动关系

为了解三沙湾大型底栖动物群落结构以及区域内水产养殖活动对其产生的影响,依据2016年夏季采集的样品数据,分析底栖群落结构、群落与环境因子的相关性以及典型群落参数在不同类型水域(鱼类网箱、海带吊绳、鲍鱼筏式养殖水域和自然水域)间的差异。结果表明,三沙湾共发现大型底栖动物6门75种,群落丰度和生物量均值分别为371.34个·m^-2和21.82 g·m^-2。其中,丝异须虫(Heteromastus filiformis)、不倒翁虫(Sternaspis scutata)、欧努菲虫(Onuphis eremita)、索沙蚕属一种(Lumbrineris sp.)和角海蛹(Ophelina acuminata)等多毛纲动物为数量优势物种,常在鲍鱼筏式和鱼类网箱养殖水域形成较高种群数量。物种数(N)、丰度(S)、生物量(B)和Shannon-Wiener多样性(H′)、Pielou均匀度指数(J′)、Margalef丰富度指数(d)等群落参数在不同水域之间无显著差异(P>0.05)。聚类分析结果显示,区域内群落空间异质性较高,空间差异未反映出水域类型的差别。水深、底层水体温度和盐度、沉积物含水率、粉砂-黏粒比例、总氮含量以及总有机碳含量等环境因子和群落相关性较强。综上,三沙湾底栖群落在群落参数方面与我国沿海温带水域相似,但群落的物种组成和较高的空间异质性较为独特;物种组成可表征网箱养殖活动的底栖生态效应。     

Use of macrobenthic infaunal communities in the monitoring and control of the impact of marine cage fish farming

Benthic macrofaunal community changes are used extensively to monitor the impact of polluting discharges to the marine environment. Regulatory and pollution control authorities have recognized the particular value of the well studied and reported responses of infaunal communities to organic pollution including wastes from aquaculture. Benthic systems are embraced in both the consent (licence) to discharge and monitoring procedures for marine cage fish farms in the Clyde River Purification Board's (CRPB) area. The relevant protocols of the CRPB are described and data are presented from impact studies throughout west central Scotland, focussing on the sedimentary environment (macrobenthos, organic carbon and redox: Eh). Macrobenthic infaunal responses, though not fully understood, were considered to provide the best measure to date of determining the impacts of organic wastes from cage fish farming and a possible way forward in developing benthic Environmental Quality Standards (EQSs) for aquaculture. Some patterns in physico-chemical data were identified, but frequently, the relationship both with benthic infaunal data and each other were inconsistent. Grossly impacted faunal communities varied little between sites and could readily be described by the simple community determinands of abundance (A), species richness (S) and Shannon Weiner diversity index (H). Moderate to lightly impacted zones were less easily defined but detailed faunal studies have allowed the selection of some widely distributed marker species. However, site-specific observations emphasized the site individuality and difficulties of setting EQSs across the industry. Using the principles of enhanced species populations and by identifying marker species, measurable impacts were found to extend further than previously reported. In naturally enriched systems, like the Firth of Clyde and some sea lochs, difficulty in separating slight effects from background was experienced. Continued monitoring and impact assessment, as well as building a better biological data base, may help develop appropriate benthic EQSs relating to aquaculture.     

胶州湾及其邻近海域鱼类群落结构及与环境因子的关系

 为了进一步研究胶州湾及其邻近水域鱼类群落结构及与环境因子的关系, 本文根据2011年冬季(2月)、春季(5月)、夏季(8月)和秋季(11月)在胶州湾及其邻近海域进行的渔业资源和环境调查数据, 应用相对重要性指数、生态多样性指数和多元分析方法等研究了胶州湾鱼类群落结构及其季节变化, 并分析了胶州湾鱼类群落结构与主要环境因子的关系。结果表明: 本次调查共捕获鱼类57种, 隶属于2纲10目31科46属, 种类组成以暖温性和暖水性鱼类为主。主要优势种有方氏云鳚(Pholis fangi)和六丝钝尾虾虎鱼(Amblychaeturichthys hexanema)等。胶州湾鱼类群落物种丰富度指数D的季节变化范围为1.02~1.65, 多样性指数H’变化范围为1.36~1.73, 均匀度指数J′变化范围为0.61~0.76。方差分析表明, 丰富度指数的季节变化显著, 而均匀度指数J′和多样性指数H′无显著性季节变化。单因子相似性(ANOSIM)分析表明, 胶州湾鱼类群落结构和种类组成存在明显的季节更替现象。相似性百分比分析(SIMPER)表明, 方氏云鳚、六丝钝尾虾虎鱼、细纹狮子鱼、斑、赤鼻棱鳀和皮氏叫姑鱼等是造成群落结构季节变化的主要分歧种。典范对应分析表明, 影响胶州湾及其邻近海域鱼类群落结构的主要环境因子为水温、盐度和pH, 其次是底质类型, 条件效应分别为0.310、0.084、0.176和0.256。本研究旨在通过分析胶州湾鱼类群落结构和多样性特征及其与环境因子的关系, 为胶州湾渔业资源的保护和可持续利用提供科学依据。

     

赤水河流域秋季底栖硅藻群落结构特征及水质评价

为研究赤水河流域底栖硅藻群落特征及水质状况,2019年9月测定了赤水河流域36个代表性样点的水体理化指标,调查了底栖硅藻群落组成,并应用硅藻指数评价了赤水河流域的水质状况。结果表明：秋季赤水河流域上游的电导率和总磷、总氮浓度均高于下游;调查采集到底栖硅藻29属138种,其中扁圆卵形藻多孔变种(Cocconeis placentula var. euglypta)、变异直链藻（Melosira varians）、极细微曲壳藻（Achnanthes minutissima）和谷皮菱形藻（Nitzschia palea）等为秋季赤水河流域优势种;下游底栖硅藻群落稳定性高于中上游;CCA结果显示可溶活性磷（SRP）和总氮（TN）是影响赤水河流域底栖硅藻群落的主要环境因子。TDI和CEE硅藻指数评价结果表明,赤水河流域水质等级整体为“中等”,55.6%的样点水质等级为“中等”以上,8.3%的样点水质等级为“极差”。     

The significance of shore height in intertidal macrobenthic seagrass ecology and conservation

相似文献   

Impact of fish and pearl farming on the benthic environments in Gokasho Bay: Evaluation from seasonal fluctuations of the macrobenthos

ABSTRACT: In order to clarify the influence of mariculture on the benthic fauna, samples of the macrobenthos were collected from Gokasho Bay, where intensive fish culture and pearl oyster culture have been carried out. Monthly samples collected from the fish farm and pearl farm sites during June 1995 to July 1996 revealed that the community structure of the two sites showed distinct differences with seasonal fluctuations. At the fish farm site, azoic conditions were found from July to November; after December, the diversity increased markedly through successive recruitments of small-sized species such as the polychaetes Capitella sp. and Pseudopolydora paucibranchiata , and the amphipods Aoroides spp.; macrofaunal density, biomass and species richness peaked from March to April. At the pearl farm site, a higher diversity, including larger-sized species, and no clear seasonal fluctuations in abundance was found, and the community structure was similar to that at the control site. These results show the large impact by fish farming on the macrofauna, whereas pearl farming causes less effect on the benthic fauna. It is suggested that the difference in the level of organic input between the two sites results in the differences in the dissolved oxygen content of the bottom water, sulfide content of the sediments and, subsequently, the macrobenthic assemblages.     

Distribution patterns of larval myctophid fish assemblages in the subtropical–tropical waters of the western North Pacific

We examined larval myctophid fish assemblages and their distribution patterns, based on discrete depth sampling. Samples were collected at 19 stations along a transect that crossed the subtropical–tropical waters of the western North Pacific. In total, we collected 27 189 larvae of 40 myctophid species or types, belonging to 15 genera. Three assemblages were recognized, based on their species composition: Kuroshio Axis (KuA), Kuroshio Countercurrent (KCC), and Subtropical Countercurrent–North Equatorial Current (SCC–NEC) assemblages. The distributions of these assemblages were well defined by the positions of the KuA and the Subtropical Convergence. Each species had a specific distribution depth, and none showed diel vertical migration. Larvae of the subfamily Lampanyctinae were distributed in shallower waters (0–50 m) than larvae of the subfamily Myctophinae (50–150 m). Larvae of the same species were distributed at lower depths in the SCC–NEC area than in the KCC area. This corresponded to the abundance of chlorophyll a, which would reflect abundance of prey organisms such as copepod nauplii and copepodites.     

Preliminary experiments on the development of extensive culture methods for juvenile sole, Solea solea (L.)

Abstract. The effect of different levels of organic enrichment on benthic productivity was studied over a 16-week period in trays of sediment placed in a fertilized seawater pond. Primary and secondary planktonic production were also monitored. The exploitation of these sources of food by juvenile sole and their growth and survival over an 8-week period were assessed.
The colonization of the sediments showed a marked succession. Nematodes were numerically the most abundant group and reached a peak after about 8 weeks. This was followed by a peak in the abundance of epibenthic copepods after 11 weeks. The maximum numbers of poiychaetes and larger Crustacea (mainly amphipods) occurred at the end of the trial (15 weeks). The high-organic sediment supported fewer polychaetes and copepods than either the low- or medium-organic sediments. The species composition of the benthos varied both with the level of organic enrichment and with time. Peaks of zooplankton concentrations of 23 to 25 organisms/l occurred during the spring and late summer. There was some evidence of an inverse relationship between zooplankton abundance and standing crop of algae, as indicated by chlorophyll a concentrations.
Harpacticoid copepods were the dominant food item consumed by small (21-50mm total length) sole. Polychaetes, amphipods and Crangon spp. were exploited by large (61-90mm total length) sole to a much greater extent, though harpacticoid copepods were also commonly taken.
The percentage increase in length of the juvenile sole at low-, medium- and high-organic levels was 108, 146 and 152 respectively. Survival, however, was highest (100%) on the untreated sediment and lowest (57%) at the medium-organic level.     

黄河口邻近海域浮游植物群落及其多样性的长期变化(1960-2010)

研究了1960―2010年黄河口邻近海域浮游植物群落及其多样性的长期变化,数据来源于19次调查245份样品。使用小型浮游生物网垂直采集浮游植物样品,于光学显微镜下进行分类统计。共鉴定出浮游植物108种,其中硅藻(Bacillariophyta)87种,甲藻(Pyrrophyta)17种,角毛藻(Chaetoceros spp.)和圆筛藻(Coscinodiscus spp.)分别出现了27种和10种。浮游植物总丰度年代际平均为2.74×10~6 ind/m~3,在20世纪80年代出现峰值,高达16.8×10~6 ind/m~3。硅藻在20世纪占据优势,群落以角毛藻、圆筛藻等大的中心硅藻为主,进入21世纪后出现小型化的趋势,舟形藻(Navicula spp.)、新月菱形藻(Nitzschia closterium)等羽纹硅藻以及具槽帕拉藻(Paralia sulcata)等底栖性物种开始形成优势。甲藻丰度出现了上升的趋势,角藻(Ceratium spp.)、夜光藻(Noctiluca scintillans)、原多甲藻(Protoperidiniumspp.)开始增多。50年来,星脐圆筛藻(C.asteromphalus)、辐射圆筛藻(C.radiatus)、柔弱角毛藻(C.debilis)、伏氏海线藻(Thalassionema frauenfeldii)等物种在群落中一直占据较为明显的优势,但是优势种组成演替和格局转换明显。在黄河持续断流和强厄尔诺事件的共同影响下,口区浮游植物丰度和多样性在20世纪末降至最低,平均仅为87.7×10~4 ind/m~3和1.97(Shannon-Weaver指数)。进入21世纪后,调水调沙等人类活动对口区浮游植物丰度和多样性水平的改善产生了积极影响,较20世纪末分别有了2.3倍和16.8%的增加,呈现出稳步回升的趋势。对黄河口浮游植物群落及其多样性长期变化过程的研究,为河口生态系统演变和健康保护、渔业资源的增殖养护提供了基础资料。     

枸杞岛海藻场大型底栖无脊椎动物摄食类群研究

随着海洋生态学研究的深入和海洋环境监测的需要,一些传统的研究方法如多样性指数等在评价大型底栖生物群落结构变化时显得说服力不足,而摄食功能群的研究越来越受到重视。本实验根据2012年8月对浙江枸杞岛海藻场大型底栖无脊椎动物的调查实验,分析该海域夏季大型底栖无脊椎动物摄食类群的组成、空间及数量分布,并进行相关生态评价。结果表明,枸杞岛海藻场夏季大型底栖无脊椎动物组成以肉食者和滤食者占较大优势,食碎屑者、植食者和食底泥者次之,杂食者最少;肉食者的优势种为布尔小笔螺、寄居蟹、扁平管帽螺、甲虫螺和四齿矶蟹等,滤食者的优势种为条纹隔贻贝、带偏顶蛤、短石蛏和布氏蚶等,植食者的优势种为钩虾、单一丽口螺和锈凹螺等;各摄食类群水平分布较均匀,垂直分布受水深和摄食饵料的限制;基于大型底栖无脊椎动物功能类群的生态参数评价结果表明,枸杞岛海藻场大型底栖无脊椎动物群落健康状态呈虚弱水平,大部分站位大型底栖无脊椎动物群落受到轻度扰动,底栖生态质量状况较好。     

Potential impacts of non‐native channel catfish on commercially important species in a Japanese lake,as inferred from long‐term monitoring data

相似文献   

Effects of fish species richness and assemblage composition on stream ecosystem function

Abstract –  Biodiversity is declining across aquatic ecosystems because of biological invasions and species extinctions. Because fishes have pervasive effects on ecosystems through species-specific food web interactions, alterations to species and functional richness, and composition of natural assemblages could have negative effects on aquatic ecosystem function. In this study, I tested the effects of fish species and functional richness, and assemblage composition on primary production (PPR), benthic invertebrate density, and benthic particulate organic matter (BPOM) in a 42-day experiment in artificial stream mesocosms. I found that fish species richness and assemblage composition were important predictors of PPR in stream mesocosms. However, the effect of species richness on PPR increased with time, suggesting that richness-related effects might strengthen as the magnitude of community-level interactions increases in ecosystems. There was no effect of fish species or functional richness or assemblage composition on benthic invertebrate densities or BPOM. These data provide additional support that fishes can be important regulators of ecosystem function in aquatic systems, and suggest that positive effects of fishes on ecosystems can be strengthened by increased species richness and composition of the assemblage. This study broadens the applicability of the biodiversity ecosystem-function literature to a new suite of taxa, supporting the overall hypothesis that ecosystem functions and services are likely to decline in response to species extinctions.     

东莞生态园湿地鱼类群落结构

为了解东莞生态园湿地水域群落结构特征,探讨2种类型刺网(沉网和浮网)及不同网目网片渔获物组成的差异性,实验利用多网目(1.0、1.25、1.6、2.0、2.5、3.1、3.9、4.8、5.8、7.0、8.6和11.0 cm)单层刺网对该湿地的鱼类进行了调查。研究期间共采集到13种鱼类,相对重要性指数显示,海南似和莫桑比克罗非鱼为优势种,前者密度最高(占84.8%),后者生物量居多(40.2%)。渔获物物种组成沉浮网间差异显著,但单位努力捕捞数量(NPUE)、单位努力捕获重量(BPUE)及物种数与沉浮网间均无显著差异;海南似的NPUE在2种类型刺网间无显著差异,但莫桑比克罗非鱼和尼罗罗非鱼的NPUE浮网显著低于沉网。12个网目网片的渔获物物种聚成2类,1.0～2.0 cm网目网片渔获物聚为1类,海南似为指示种;2.5～11.0 cm片的聚为另1类,莫桑比克罗非鱼和尼罗罗非鱼为指示种。渔获物大小结构聚为2类,1.0～3.9 cm网目网片渔获物聚为1类,4.8～11.0 cm网目网片的聚为另1类。随着网目大小增加,渔获物平均体长线性递增,NPUE呈幂函数式下降。研究表明,为对内陆水域鱼类群落...     

Enrichment of aquaculture earthen ponds with Hediste diversicolor: Consequences for benthic dynamics and natural productivity

The present work analysed the potential impacts of the enrichment of semi-intensive production earthen ponds with the ragworm Hediste diversicolor in the benthic dynamics and natural productivity. The macrobenthos and sediment characteristics were analysed in two enriched ponds and two control ponds in May, June and September 2005. The number of species, Margalef species richness and biomass (AFDW) were generally significantly higher in enriched than in control ponds, while for abundance no clear pattern was visible. Multivariate analysis showed differences in macrobenthic community structure of control and enriched ponds. Differences were also visible when the introduced species was removed from the data set, indicating that differences were mainly due to changes in other species abundance. In general, gastropods (Akera bullata, Jujubinus striatus, Hydrobia ulvae, Rissoidae), bivalves (Abra ovata, Cerastoderma spp.), crustaceans (Ampithoe rubricata, Dexamine spinosa, Gammarus insensibilis, Gammarella fucicola, Iphinoe tenella), and also some polychaetes (Desdemona ornata, Terebella spp., Syllis gracilis and Neanthes caudata) greatly increased their abundances in enriched ponds. On the other hand, the abundance of Tubificidae, Capitella spp., Pseudopolydora paucibranchiata, Corophium acherusicum, and Mesopodopsis slabberi decreased. The organic matter content was significantly lower in enriched ponds, probably due to the positive impact of the polychaetes on sediment reworking, resulting in higher organic matter mineralization. Overall the present study indicates that stocking of earthen production ponds with H. diversicolor significantly altered community structure of benthic invertebrates and may improve environmental conditions for fish production by reducing the organic matter accumulation in pond sediments.     

Food web feedbacks drive the response of benthic macrofauna to bottom trawling

Bottom trawl fisheries have significant effects on benthic habitats and communities, and these effects have been studied intensively in the last decades. Most of these studies have related the changes in benthic community composition to direct effect of trawl gears on benthos, through imposed mortality. This line of argumentation ignores the fact that benthic organisms themselves form a complex food web and that bottom trawling may trigger secondary effects through this food web. We studied the potential consequences of such food web effects using a model of benthic predators, filter feeders, deposit feeders and fish. Our analysis shows how inclusion of ecological interactions complicates the relationship between bottom trawling intensity and the state of the benthic community and causes a non‐linear and non‐monotonic response of the benthic community to trawling. This shows that indirect food web effects can fundamentally alter the response of a benthic ecosystem to bottom trawling, compared to the direct effects of mortality. In light of our results, we argue that indicators of fishing impact on benthos need to account for positive as well as negative effects of bottom trawling, in order to accurately quantify the impact. Our findings highlight that understanding the food web ecology of the benthic ecosystem is crucial for understanding and predicting the effects of trawling on the seafloor. Work that promotes such understanding of the food web ecology seems a more productive research strategy than conducting ever more empirical trawling effect measurements.