Abundance Biomass Comparison Research Articles

Decadal variation and temporal stability of the macrobenthic community in the Bohai Sea, China

Biodiversity in the Bohai Sea is threatened by climate change and human activities. An analysis based on decadal macrobenthic community data was conducted to assess the ecological health. These findings revealed the temporal and spatial variations in species composition and biodiversity, which were primarily influenced by depth, temperature and dissolved oxygen content. The community structure in 2014 exhibited a 70 % dissimilarity compared to other years, and biodiversity was lower in 2014. The dominant species showed a trend towards miniaturization. Abundance-biomass comparison curves indicated that community disturbance improved by implementing various policies. Overall, communities in the Bohai Sea remained stable, except in the Bohai Strait (BH), where synchronous fluctuations with an increasing trend were observed. Enhancing biodiversity and addressing the risks associated with losing single species are essential for maintaining community stability. The community also displayed synchronous tendencies in Laizhou Bay, emphasizing the need for continued long-term monitoring.

Assessing the Benthic Ecological Quality in the Intertidal Zone of Cheonsu Bay, Korea, Using Multiple Biotic Indices

With the growing global focus on marine environmental conservation and management, it is imperative to evaluate the ecological quality of marine ecosystems accurately. In this study, we employed seven biotic indices, namely the AZTI marine biotic index (AMBI), BENTIX, benthic opportunistic polychaetes amphipods index (BOPA), benthic pollution index (BPI), multivariate AZTI marine biotic index (M-AMBI), abundance biomass comparison (W-value), and Shannon diversity index (H’), to assess the benthic ecological quality in the intertidal zone of Cheonsu Bay, South Korea. Except for the H’ and W-value, the indices (AMBI, BENTIX, BOPA, BPI, and M-AMBI) suggest that the ecological quality at most stations in the intertidal zone of Cheonsu Bay was acceptable. Furthermore, the influx of a large amount of eutrophic freshwater has impacted the intertidal zone of Cheonsu Bay, but the applicability of the seven biotic indices requires further investigation.

Catch assemblages in the small-scale trap fishery with relation to hydrographic features of a tropical bay in the Gulf of Thailand.

Catches from the small-scale trap fishery in Bandon Bay, Suratthani, Thailand, were monitored from 14 sites around the Bay, then disturbance to aquatic communities and catch assemblage were examined. At the same time, the hydrographical features of the bay were surveyed. The study was conducted throughout 2019 except in December, when a tropical cyclone made sampling impossible. In total, 17,373 animals from 118 species or species groups of aquatic animals were collected. The main target of the fishery, blue swimming crab Portunus pelagicus, contributed about 10% of the total catch in terms of number; meanwhile, another crab, Charybdis affinis, was the most dominant species (41% of total). W-statistics of Abundance-Biomass Comparison curves ranged between -0.025 and 0.031, indicating light disturbance to the communities in this fishing ground. The catch assemblage, based on number in catch composition, were divided into three main clusters and six sub-clusters by using the self-organizing map (SOM) technique. The SOM results showed that the catch assemblages differed based largely on temporal variation. The hydrographic features of Bandon Bay at times exhibited a layered structure and had strong spatial variation. The bay's current system was governed by motion of tidal currents; meanwhile, the circulation was governed by monsoonal wind and freshwater discharges. Tidal current was strong and ranged between approximately 0.6 m to 2.2 m. Water within the bay was always warmer than the outer sea. High water temperature was observed two times during the year: during monsoon transition 1 (April to May) and transition 2 (October). Salinity showed great spatial and temporal variation, differing by more than 5-10 ppt horizontally. It was possible to use these dynamic hydrological features of Bandon Bay to explain assemblage patterns of the trap-net catches.

Mapping breeding birds in a re-naturalized historical fortress: composition, structure and considerations about abundance vs. biomass comparisons

Using the mapping method, I obtained data about a rich, even and diversified breeding bird assemblage inhabiting an abandoned and re-naturalized historical military fortress (Rome, central Italy). Fortress and the surrounding parks host a large number of edge-mosaic, forest and synanthropic species (often localized at urban scale as Dendrocopos minor and Columba palumbus) due to a large availability of many sub-habitats and related niches (walls, cavities, tree holes, mature trees, mowed meadows, hedgerows, and deep moats). In this regard, this historical site may be considered a “key-stone structure” at the landscape scale (i.e., a mature forest/rocky patch embedded in an agromosaic suburban mosaic). The application of the Abundance/Biomass Comparison (ABC) evidenced a dominant role of large body mass species. The underlying logic behind this approach assumes that, generally, in less disturbed environments species with higher trophic level (and higher body mass) dominate: the increase in frequency of these larger species induce early cumulating biomass curves. However, in our anthropized case study, this assumption seems not valid since many large body mass species (as Columba livia dom., Psittacula krameri and Corvus cornix) show a low trophic level (e.g. granivorous or homnivorous): i.e. body mass is not an indicator of trophic level. Therefore, the pattern reported by ABC curves evidence only a dominance of large body mass species without implications on the trophic level and, consequently, on the disturbance acting on the assemblage. In this regard, assumptions linked to the ABC curves are probably not universal but only limited to specific taxa and contexts.

Effects of Manila clam Ruditapes philippinarum culture on the macrobenthic community

Macrobenthic bioturbation affects the environment, and variances in habitat, such as decreased dissolved oxygen concentration and increased ammonia concentration, affects the macrobenthic community. The relationship between macrobenthos and habitat factors may be a mutually causal relationship. The bottom-sowing culture for Manila clam Ruditapes philippinarum in many coastal countries plays an important role in coastal fisheries, and the relationship between Manila clam and other macrobenthos affects the ecological stability of the bottom-sowing culture zone. It is necessary to explore the relationship between them to manage the waters used for the bottom-sowing culture for Manila clam. In this study , from June to October 2021, the field investigation on macrobenthos including Manila clam and their habitat factors, such as particle size, nutrient content, redox potential, and organic matter content, in 21 experimental communities enclosed by bolting-silk net in Shuangdao Bay, Weihai, Shandong, China was conducted, during which macrobenthos functional groups were determined by feed sources and motor behavior. The results showed that Manila clam biomass was 7.215±0.984 g/m2 (calculated by dry soft tissue weight), and it was positively correlated with the biomass of macrobebthos functional groups B1, G1 and P1; water content in sediment; sulfide content in interstitial water; the Shanon-Wiener diversity index; Pielou’s evenness index and the W statistic of the ABC (Abundance-Biomass Comparison) curve (p< 0.05). Moreover, it was negatively correlated with sediment particulate size and HCl-NO3 content in sediment (p< 0.05). The action of Manila clam to habitats was the dominant role of the interaction between clam and habitat. Thus, the bottom-sowing culture for Manila clam does not decrease the macrobenthic community stability, and the invasion of other macrobenthos into the bottom-sowing culture zones for Manila clam may be accidental or inevitable. The results of our study suggest that the management of the bottom-sowing culture for Manila clam should be conducted from ecosystem level; i.e., fishing and aquaculture in the same waters are regarded as two components of an ecosystem; manage them together, rather than treat them separately.

Assessment of macrobenthos community and ecological status of the Jiaozhou Bay, China

Jiaozhou Bay is one of the most economically and ecologically important semi-enclosed waters along the southern Yellow Sea coast of China. Anthropogenic activities like bivalve aquaculture, sewage discharge, and oil industry have severely impacted the bay environment in the past years. Macrobenthos plays an important role in monitoring marine ecosystem health. Species composition and community structure typically shift as a response to the effects of pollution and disturbance. In this study, macrobenthos community was characterized and assessed with the sediment samples collected from 15 stations in the Jiaozhou Bay in November 2018. Abundance, biomass, species composition, diversity and community structure along with environmental variables were determined to assess the benthic ecosystem health. The ecological status of the bay was also assessed by using abundance biomass comparison curve (ABC plot) and the widely used benthic indices AMBI and M-AMBI. The results showed that combination of five variables (water depth, Cha, Pha, sediment type, and biomass of different cultured bivalve species) were the main determinants for the macrobenthos community structure in the bay. Despite for most of the stations in the bay, relatively high species richness, evenness and diversity, and the undisturbed condition indicated by ABC plots and W statistics, the dominance of opportunistic polychaetes like Micronephthys oligobranchia could show that there is some degree of disturbance in the bay. ABC plot clearly indicated the disturbance of bivalve culture of Ruditapes philippinarum on the macrobenthos community at station J3. As a comparison, the highest abundance and species richness of macrobenthos at station J4 may indicate a positive role of oyster culture Magallana gigas on the improvement of ecological condition. The benthic indices AMBI and M-AMBI suggested that the benthic ecosystem of Jiaozhou Bay was slightly disturbed and the overall ecological status of the bay was in good condition.

Changes in Fish Assemblage Structure after Pen Culture Removal in Gehu Lake, China

The removal of the net enclosure has been used as a lake management strategy in various regions of China as ecological development is given more attention. Nevertheless, little is known about the substantive impact of this measure on fish communities in inland lakes. To this end, the fish community composition and structural features after the removal of the net enclosure in Gehu Lake were explored and evaluated in this study from 2021 to 2022 and compared to the investigation before the net enclosure removal from 2017 to 2018. Belonging to 7 orders, 10 families, and 46 species, a total of 17,151 fish were collected, with pelagic, sedentary, and omnivorous species dominating. In comparison, the number of species increased by 10 after removal, and fish alpha diversity increased. The Index of Relative Importance (IRI) revealed that the composition of dominating species remained constant, including Coilia nasus, Hypophthalmichthys molitrix, and Hypophthalmichthys nobilis; Parabramis pekinensis, Megalobrama amblycephal, and Culter mongolicus were upgraded from common species to general species. Culter alburnus, Hemiculter bleekeri, and Pseudobrama simoni were downgraded from general species to common species. Elopichthys bambusa had become a common species (IRI = 109.35), which was not discovered before removal. According to the hierarchical clustering (HC) and non-metric multidimensional sequencing (NMDS), the fish community of the northern reserve was highly aggregated. As the Abundance Biomass Comparison (ABC) curve and biodiversity index indicated, the fish community structure of the whole lake was in a state of moderate anthropogenic disturbance with reduced stability, while that of the northern reserve was in a state of light anthropogenic disturbance with greater stability. The number of fish species increased in this survey compared to the period before removal, species and dominant species composition altered dramatically, and total lake stability declined. This study demonstrates that the fish diversity in Gehu Lake increased after the removal of the net enclosure. Meanwhile, the stability of the fish community structure was decreased temporarily. Lake restoration is a long-term process, and the underlying impact of the removal of the net enclosure still requires continuous monitoring and further studies.

Testing the suitability of the abundance biomass comparison bioassessment method in a Mediterranean river

The Water Framework Directive (Directive 2000/60/EC) emphasises the need for simple tools and studies to characterise aquatic ecosystems. A wide range of methods has been developed, including different groups of biota and different taxonomic resolutions. Among these, the abundance biomass comparison (ABC) method is an important methodology widely used in marine benthic systems and well-founded from the ecological point of view. This method – with a slight modification using genera and families instead of species – was applied in a Mediterranean river (Eliche-Frío, northeast of Andalusia, Spain) using the macroinvertebrate community, together with the Margalef richness index and the Iberian BioMonitoring Working Party ( IBMWP) to determine the quality of the water. The obtained results show the suitability of the ABC curves method to analyse the macroinvertebrate community and estimate the ecological status of river ecosystems. Although both, the genus and family aggregations, showed a similar trend, the values obtained with the family level indicate a worse state of contamination than those shown with the genus level. The comparison between genus and family levels with other biological indices shows that the evaluation obtained with family aggregation is more similar to those obtained with the Margalef and IBMWP indices than the evaluation based on genera; therefore, we could conclude that this level of taxonomic resolution is adequate for the use of the ABC method in assessing the ecological status of Mediterranean rivers.

Effectiveness of Biomass/Abundance Comparison (ABC) Models in Assessing the Response of Hyporheic Assemblages to Ammonium Contamination

Abundance–Biomass Comparison (ABC) models, first described for marine benthic macrofauna, have been applied successfully to other marine and terrestrial/freshwater fauna but never to ecotonal communities. In particular, to our knowledge, ABC models have not been applied to hyporheic communities. This study represents the first application of ABC models to hyporheic assemblages. We aimed at testing the effectiveness of ABC models in describing the perturbation of hyporheic communities subjected to an existing/known disturbance. To this end, we applied the models to the hyporheic community of an Apennine creek, where the hyporheic waters of the upstream stretch were uncontaminated, whereas those of the downstream stretch were contaminated by ammonium. We also tested separated models for the summer and winter periods to account for potential variability due to season. ABC models provided a satisfactory description of the hyporheic community changes due to ammonium by showing the abundance dominance curve overlying that of the biomass in the downstream stretch contrarily to what was observed in the upstream stretch. However, ABC models did not highlight any significant seasonal effects. Our results showed that ABC models have the potential to be used as assessment tools for ecological quality of hyporheic zones in temperate regions.

Ultrashort-term responses of riparian vegetation restoration to adjacent cycles of ecological water conveyance scheduling in a hyperarid endorheic river basin

The management of ecological water conveyance (EWC) can allow riparian vegetation communities to survive the threat of degradation in hyperarid inland areas and promote the health of groundwater-recharged riparian ecosystems. However, the ultrashort-term effects of periodic EWC scheduling on riparian vegetation remain unclear. This study explored the spatiotemporal differentiation in species structure (herbs, shrubs, and trees), diversity (measured by the Simpson, Shannon–Wiener, Pielou, and Margalef indices), stability (evaluated via Godron fitting distances and abundance-biomass comparison curves), and integrity (proxied by the vegetation-based index of biotic integrity) of vegetation communities in the downstream Heihe River Basin, China. Empirical orthogonal function, Pearson correlation, canonical correspondence analysis (CCA), and partial CCA methods were used to evaluate the effects of dominant habitat environmental factors from the hydrogeographic features, soil physicochemical properties, and anthropogenic impacts. The results showed that the riparian vegetation community diversity, stability, and integrity varied moderately to slightly with hierarchical distance from near wetlands (<200 m; containing mainly herbs) to far desert edges (>800 m; occupied by shrubs/subshrubs). The middle transition zone (200–800 m; occupied mostly by trees/subtrees) had the best diversity and integrity but relatively poor stability. The most significant influencing factors were EWC and soil moisture. The simple diversity, fair-level integrity, and disturbed but not irreversibly damaged stability of the vegetation community were generally improved by 14.82%, 20.33%, and 30.57%, respectively, in the pre-EWC period but worsened in the post-EWC period. The difference in spatially distributed EWC quantities caused more apparent vegetation restoration in high water-supplied subareas where certain biological community instability existed. Therefore, adequate EWC management can be considered a prerequisite for the maintenance of high richness and structural stability in local communities and requires a good balance between interregional vegetation abundance and enhanced environmental tolerance.

Analysis of Spring Community Structure and Evaluation of Ecological Niche in Tangshan Marine Ranching, China

To investigate the fishery community structure in spring at the early stage of construction of Tangshan Marine Ranching, in China. This study analyzed the relationship between species composition, diversity and community structure of fishery resources in marine ranching using survey data from March, April, and May 2017. The results showed that a total of 53 species of organisms occurred in the spring in the waters inside and outside the reef area of the marine pasture. Among them, 20 species of fish were among the chordates. 16 species of arthropods, including 6 species of shrimps and 8 species of crabs. Ten species of mollusks, including 6 species of snails. 5 species of echinoderms, 1 species of annelids, and 1 species of Cnidaria). The diversity index, evenness index and richness index outside the reef area of marine ranching in spring were greater than those in the reef area. According to cluster analysis and non-metric multidimensional scale ranking analysis, the biological communities inside and outside the reef area can be divided into four groups, with the similarity of the communities in the reef area being greater. The Abundance-Biomass Comparison curves (ABC curve) indicated that the biological communities within and outside of the reef had been moderately disturbed. The relative importance index and niche analysis demonstrated that there had been sufficient bait in the reef area, and the ecological structure of the marine ranching was taking shape.

Effects of fishing and environmental parameters on the commercial bony fish assemblage in the southern Caspian Sea

Since the 1990s, anthropogenic activities have been the major direct or indirect threats to the structural and functional organization of the unique ecosystem of the Caspian Sea (CS). This study attempts to investigate the relationships between fish community structure and environmental parameters and to analyze the Abundance Biomass Comparison (ABC) in the CS. The input data, including catch data by species and environmental parameters, were collected from 1996 to 2017. Of the 13 bony fish species identified, only two species Rutilus kutum and Chelon aurata accounted for 47.14% and 62.65%, and 40.80% and 29.34% of CPUE and NPUE, respectively. DisTLM revealed that five environmental variables showed a significant linear relationship with the NPUE resemblance matrix. Based on the AIC criteria, the combination of year, precipitation, SST_Apr, SSL, SST, GTA, Iranian rivers, and Volga discharges explain 80.3% of the total variability. Based on the ABC curves and W statistics, it was concluded that the fish assemblage was environmentally stressed from 1996 to 2003. The Shannon diversity index (H´) showed a decreasing trend, suggesting that fish species have been exposed to increasing stress over the past 22 years. Considering the current environmental conditions (downward trend in SSL river discharge and increase in SST) and anthropogenic activities, it appears that the downward trend will continue in the future.

青弋江流域大型底栖动物群落结构及水质评价

PDF HTML阅读 XML下载 导出引用 引用提醒 青弋江流域大型底栖动物群落结构及水质评价 DOI: 10.5846/stxb202101240247 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金青年项目（41301029）；安徽高校协同创新项目（GXXT-2020-075） Macroinvertebrate community structure and water quality assessment in the Qingyi River Watershed Author: Affiliation: Fund Project: The National Science Fundation of China(General Program, Key Program,Major Research Plan) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:研究河流大型底栖动物群落结构特征及水环境质量对水生态的保护与修复具有重要意义。以青弋江流域为研究对象，于2020年9月进行了大型底栖动物及水体理化因子的调查，采用相对重要性指数、生物多样性指数及Jaccard相似性系数分析了大型底栖动物群落结构特征，运用丰度/生物量比较曲线法及冗余分析法探究了底栖动物群落受到的干扰程度及其主要影响环境因子，最后利用水生态环境质量综合指数对河流水质进行评价。研究结果表明：（1）共采集鉴定大型底栖动物61种，隶属于3门6纲17目，平均丰度为265.9个/m2，平均生物量41.6 g/m2。相对重要性指数分析显示，日本沼虾（Macrobrachium nipponensis）、中国圆田螺（Cipangopaludina chinensis）、羽摇蚊（Chironomus plumosus）及扁蜉（Ecdyrus）为群落中的主要优势种。（2）由群落相似性分析知，Jaccard相似性系数较低，调查点位之间存在较强的空间异质性。（3）冗余分析表明，电导率、氨氮浓度及流速是影响底栖动物群落结构的主要环境因子。（4）生物指数分析结果显示该流域水质为轻度污染或中度污染，与水质理化因子评价存在较大差异。综合考虑生物及非生物因子的水生态环境质量综合指数模型计算结果显示，流域整体水环境质量偏好，但部分采样点已受到干扰或处于污染状态，与ABC曲线分析及优势种分析基本一致，评价结果更具科学性及可靠性。 Abstract:It is of great significance to study the community structure of macrobenthos and the water quality for protection and restoration of aquatic ecology. Taking the Qingyi River Basin as the research object, a survey of macrobenthos and physicochemical factors of the water body was carried out in September 2020. It analysed the structural characteristics of the macrobenthic community by means of the relative importance index, the biodiversity index and the Jaccard similarity coefficient. It investigated the extent of disturbance to the benthic community and the main environmental factors that affect it, by applying the comparative abundance/biomass curve method and redundancy analysis. Finally, the comprehensive index of water ecological environment quality was used to evaluate the river water quality. The results showed that (1) 61 species of macrobenthos were collected and identified in the Basin, which belonged to 3 phyla, 6 classes and 17 orders. The average density was 265.9 ind/m2 while the average biomass was 41.6 g/m2. The main dominant species which were shown in the index of relative importance in the community were Macrobrachium nipponensis, Cipangopaludina chinensis, Chironomus plumosus, and Ecdyrus. (2) The Jaccard similarity coefficient was low due to the analysis of community similarity, with a strong spatial heterogeneity between the investigation sites. (3) The main environmental factors-conductivity, ammonia nitrogen concentration and flow velocity-influenced the community structure of macrobenthos by the redundancy analysis. (4) The biological index analysis results indicated that the water quality in the basin was lightly or moderately polluted, which varied significantly from the assessment of the physical and chemical factors of water quality. The comprehensive water and ecological quality index model calculations, which integrated biotic and abiotic factors, suggested an overall water and environmental quality preference for the basin. But some sampling points have been disturbed or polluted, which was basically consistent with the abundance-biomass comparison curves analysis and the dominant species analysis, in which the result of evaluation was more scientific and reliable. 参考文献 相似文献 引证文献

Assessment of Benthic Ecological Quality Status Using Multi-Biotic Indices Based on Macrofaunal Assemblages in a Semi-Enclosed Bay

Semi-enclosed bays have physical and chemical characteristics influenced by both land and sea systems and the quality of the benthic environment is always of great concern. Macrofauna are considered good indicators for evaluating the benthic ecological quality status owing to their biological characteristics. In this study, six biotic indices, namely the Shannon–Wiener diversity index (H′), Abundance-Biomass Comparison (ABC) curve, AZTI’s Marine Biotic Index (AMBI), multivariate-AMBI (M-AMBI), BOPA index, and BENTIX index, were used to evaluate the adaptability of different biological indices in the bioassessment of the benthic environment in a semi-enclosed bay. In the annual environmental assessment of the study area, the average values of the six indices (H′, ABC curve, AMBI, M-AMBI, BOPA, and BENTIX) were 4.494, 0.182, 2.433, 0.791, 0.033, and 3.813, respectively; accordingly, H′, M-AMBI, and BOPA met the high standards whereas the other indices met the good standards, indicating that the whole study bay was slightly disturbed and had good ecological quality. From the perspective of spatial variation, the benthic environment in the middle of the bay was better than that in the north; the environmental problems in the northeast were particularly noteworthy. In terms of temporal patterns, the benthic environment in winter and summer was significantly better than that in spring and autumn, with obvious seasonal differences. The present results indicate that the H′ and ABC curve based on benthic abundance and biomass should be avoided for environmental assessment in mariculture areas. AMBI and M-AMBI should be used with caution when the percentage of unassigned species is high, in which case H′ is the appropriate choice. When there are few unassigned species, M-AMBI is more conducive for accurate evaluation of the benthic environment than AMBI and H′.

Evaluation of Fish Communities in Daya Bay Using Biomass Size Spectrum and ABC Curve

Based on the data collected by four trawl surveys during 2016–2017, we applied biomass size spectrum (BSS) and abundance–biomass comparison (ABC) curve to assess the status of fish communities’ status in Daya Bay, China. Our findings indicated a unimodal pattern and biomass size ranged from −2 to 10 grain levels and the pattern of the Sheldon-type BSS of fish in Daya Bay. Moreover, fishes in the range of four to eight size class were relatively abundant. The highest peak belonged to the two to four grain level (log2 size bins), mainly consisting of Leiognathus brevirostris, Callionymus meridionalis, Callionymus koreanus, Evynnis cardinalis, Trachurus japonicus, and other small fishes. The curves of the BSS in spring and winter were relatively flat and comprised a large curvature. The summer and autumn curves were comparatively steep, and the seasonal curvature was small. The curvatures of the curve were mainly related to a large number of small Evynnis cardinalis and a small number of large-sized Harpadon nehereus and Leiognathus ruconius. In our study, it was observed that the number and the size of the breeding population, trophic levels, migration habits, and other life history characteristics, as well as anthropogenic disturbances (especially overfishing), significantly affected the peak shape, slope, or curvature of the fish BSS, with overfishing being the main factor. The ABC curve exhibited that Daya Bay was in a critical state of disturbance throughout the year. The spring, summer, and autumn were in severe disturbance, while the winter was in moderate disturbance.

Assessment of marine environment by ABC (abundance biomass comparison) analysis—A case study on western offshore area of Arabian Sea

Assessment of the variations in marine ecosystem can be effectively monitored using benthic fauna because pollutants from any source will ultimately end in the seabed. The benthic communities play an important role in the transfer of materials from primary production through detrital pool into higher tropic levels, including commercially exploitable fish. Majority of the benthic fauna are sedentary and sessile in nature and cannot avoid any environmental perturbation, hence are considered sensitive indicator of change in the environment caused by natural and anthropogenic disturbances. Based on the analysis of abundance and biomass of benthic communities, one very important and effective study in analyzing marine environment i.e. ABC (Abundance-Biomass Comparison) has been adopted in this paper.

Fish species composition, distribution and community structure in the Fuhe River Basin, Jiangxi Province, China

This study examined the status of fish resources in the Fuhe River Basin, Jiangxi Province, China, from March 2018 to February 2019. A total of 25,915 individuals, belonging to 6 orders, 18 families, 61 genera, and 85 species, were collected from nine sampling sites, with Cypriniformes accounting for 57.65% of the total number of species. Overall, the samples were dominated by mountain-stream species inhabiting middle-lower reaches, with an omnivorous feeding habit and drifting eggs. Moreover, 73 species were defined as of Least Concern on the International Union for Conservation of Nature (IUCN) red list, while 10 species were Data Deficient, 1 was Endangered, and 1 was Near Threatened. A total of 29 species were endemic to China. According to the relative importance index, five dominant species (Squalidus argentatus, Xenocypris macrolepis, Cyprinus carpio, Carassius auratus, and Pseudobrama simoni) were recorded. The Margalef richness index, Shannon-Wiener diversity index, Simpson dominance index and Pielou evenness index were subsequently calculated at 8.27, 3.09, 0.70, and 0.09, respectively, while cluster analysis and non-metric multi-dimensional scaling analysis divided the 9 sampling points into 4 clusters at a level of 17%, consistent with the results of Jaccard similarity analysis. ANOSIM further revealed significant differences among fish communities (P < 0.01), while SIMPER showed that the typical species in each group were, to some extent, also the most divergent and dominant species in the community. The results of abundance-biomass comparison curves also showed that the fish communities of the Fuhe River Basin are in a severely disturbed state, although the level of disturbance varied spatially. Thus, the survey of fish resources in Fuhe River Basin plays a vital role in the protection and management of aquatic biological resources and the governance of aquatic ecological environment.

Detecting Environmental Stress of Tropical Lagoon Using Abundance-Biomass Curve of Benthic Macroinvertebrate Assemblages (Ebrié lagoon, Côte d'Ivoire, West Africa)

Sectors IV and V of the Ebrié lagoon are increasingly experiencing fish mortality. The abundance biomass comparison (ABC) is graphical method use to assess the level of environmental disturbance in this area. The aim of the study were to detect the environmental changes caused by anthropogenic activities using ABC curve of benthic macroinvertebrate assemblages presented in the studied areas. Results of the ABC analyses indicated that stations L, K and M are less stressed with biomass curve above abundance curve. Stations N and A recorded a stressed environment with abundance curve above biomass curve. The ABC plots showed that N and A stations could be classified as moderately disturbed and polluted. The Clarke's W index to the benthic macroinvertebrates data, confirmed this situation; it ranged from -0,129 (N) to 0,224 (L). The results of the present study can be extrapolated to other tropical wetland systems to predict the levels of disturbance and to identify characteristic organisms to predict the environmental conditions in the wetland health assessment program.

Long-term variations in fish community structure under multiple stressors in a semi-closed marine ecosystem in the South China Sea

Daya Bay is an ecologically and economically crucial semi-closed bay along the southern coast of China. It is proven to be a stressed ecosystem and therefore obviously vulnerable to further extrinsic disturbance. This study used fish data from bottom-trawl surveys, conducted from 1985 to 2018, to analyze variations in the fish community structure over the past 30 years. The results showed that warm-water fish species were overwhelmingly dominant during all years, suggesting the bay's tropical to subtropical characteristic. By 2015, the number of fish species had decreased by 29.44% of that caught in 1987, moreover, values of the Shannon–Wiener diversity index and the Margalef richness index were lower in 2015 compared to 2004. There were evident shifts in the fish community composition from pelagic to demersal species, as suggested by the dominant species found in springtime, the dominant families, and percentages denoting the numbers of species in the main orders. Average fish body weight in landings declined from 13.4 g to 7.58 g, the body sizes of four typical commercial fish species decreased by varying degrees over the last 30 years. Abundance–biomass comparison curves suggested that the Daya Bay fish community was more stressed in 2015 than in 2004 during all seasons, except winter. In general, the fish community structure in Daya Bay is consequently in an unsteady state. Multiple anthropogenic disturbances, such as fishing (including overfishing and changes in the main fishing gears), the destruction of natural habitats, pollutants, and anthropogenically induced temperature changes, are likely to have caused obvious shifts in the bay's fish community structure. Therefore, we emphasize the need for integrating management of multiple anthropogenic stressors to achieve ecosystem-based management.

Assessing the ecological health of the Chongming Dongtan Nature Reserve, China, using different benthic biotic indices

To assess the ecological health of the Chongming Dongtan Nature Reserve (CDNR), univariate and multimetric indices—AZTI's Marine Biotic Index (AMBI), multivariate AMBI (M-AMBI), abundance-biomass comparison curves, taxonomic diversity, Shannon-Wiener index (H′) (log2), and Benthic Opportunistic Polychaetes Amphipods index (BOPA) — were used to translate the macrobenthic community into classifications of ecological health in 2016 and 2017. Based on the results of the various indicators, the overall habitat status of the CDNR ranged from good to high status. Sites 4 and 5, which fell in the remaining tidal flats following reclamation activities, were classified as disturbed, whereas the degree of disturbance at site 3 was low. The results indicate that the CDNR is under some form of human disturbance, which includes reclamation and animal (mainly cattle) grazing. H′ (log2) and M-AMBI index may be more suitable for assessing ecological quality in intertidal zones, including the CDNR.