Species In Autumn Research Articles

Spatial Patterns of Larval and Juvenile Fish Assemblages in an Eddy Area in the Western South China Sea

The objective of this study was to investigate influence of meso-scale eddies in the western South China Sea on species composition and spatial patterns of fish larvae and juveniles based on the data collected during summer and autumn in 2012. Nintyeight species belonging to 38 families were collected, including 78 species in summer and 41 species in autumn. The dominant species in summer were Vinciguerria sp. (39.70%), Stephanolepis cirrhifer (11.21%), Caranx sp. (5.45%) and Benthosema pterotum (1.97%). The dominant species in autumn were Gobiidae sp. (15.32%), Ceratoscopelus townsendi (7.26%), Diaphus sp. (6.45%), Astronesthes sp. (5.65%) and Callionymidae sp. (4.03%). Abundance of fish larvae and juveniles in summer was higher than that found in autumn. Similarity cluster analysis results indicated that larval fish assemblages in summer can be divided into two communities: (1) larval fish in the cyclonic eddy; (2) larval fish in the anticyclonic eddies. While in autumn, the larval fish assemblages can be divided into three communities: (1) larval fish without influence of the cyclonic eddy; (2) larval fish influenced slightly by the cyclonic eddy; (3) larval fish gathered near the center of the cyclonic eddy. The variations of abundance and assemblage of larval fish might be attributed to sea surface temperature (SST), sea surface salinity (SSS) and sea level anomaly (SLA).

Significance of wetland and it’s dependent Avifauna in Bangoli Wetland Complex, Raipur District, Chhattisgarh, India

The Bangoli complex of wetlands is situated in central region of Chhattisgarh. This region is part of the Mahanadi river basin and is predominantly a plain area with the good number of tanks and village ponds. The geography of the area is mainly plains dotted with wetlands and sparse trees, thereby attracting both resident and migratory species. The aim of this study was to determine the avian diversity and composition in this complex, as no previous specific study was found undertaken, The available studies were either for specific species or covered the whole of the state. Our study spanned from the year 2015 to 2021. During the period the complex was visited intermittently covering all seasons and using standard methodology for observation and documentation, covering wetlands and their surroundings. This study area of the Bangoli complex comprised of five major wetlands and five smaller tanks, all situated within the area of about 20 sq km.. Our study revealed the presence of 293 species belonging to 20 orders and 69 families. The encountered species were categorized in Occurrence status as Resident (R)171 and Migratory(M) 122 in numbers respectively; Passerby mainly coastal species in Autumn and Spring seasons, Habitat used like Aquatic(A), Near Aquatic(NA)(Shore) , Grass and Arboreal (GA), Himalayan and sub-Himalayan species and Important Nesting species. Study also revealed presence of four new species unreported from central region. Also, 11 Threatened species as per Birdlife International- IUCN (2020) were identified in categories EN – 1, VU – 4, NT – 6. These wetlands are subjected to threats of the killing by snares and traps particularly in the winter season, commercial exploitations like fishing, cultivation , amusement, fodder collection and grazing,. The destruction of habitats caused by stone quarries and crushers, felling of trees are of another major concern.

Molecular Identification of Species Diversity Using Pelagic Fish Eggs in Spring and Late Autumn-Winter in the Eastern Beibu Gulf, China

The Beibu Gulf is considered as one of China’s four major fishing grounds, although the substantial overexploitation of fisheries has led to the collapse of many fish stocks, and to changes to spawning grounds in recent decades. Classifying fish eggs is an important way to monitor the recruitment process and identify the spawning sites of fish. However, the lack of a basis for morphological identification and difficulties in correctly identifying fish eggs based on morphological characteristics has limited scientific studies. In the present study, we identified fish eggs using molecular detection of cytochrome c oxidase subunit I and cytochrome b fragments. Ichthyoplankton surveys were conducted in the spring and late autumn–winter of 2020 in the eastern Beibu Gulf. Among the DNA extracted from the 873 chosen fish eggs, we successfully obtained 541 high-quality cytochrome c oxidase subunit I sequences and 41 high-quality cytochrome b sequences. We successfully identified 212 fish eggs (36.4%) from 32 species; 291 eggs (50.0%) showed ambiguous species delimitation, and 79 eggs (13.6%) could not be identified. Among the identified species, we found 25 species in spring and 25 species in late autumn–winter, out of which 18 species occurred in both seasons. We also obtained high resolution photographs of fish eggs at the species level for further morphological analysis and identification. The present study confirms the efficacy of using molecular methods to identify fish species from eggs and provides valuable information for protecting the spawning ground of economically valuable fish and for managing fishery resources.

Characteristics of VOCs and Formation Potentials of O3 and SOA in Autumn and Winter in Tongchuan, China

Volatile organic compounds (VOCs) are the main precursors of tropospheric O3 and secondary organic aerosol (SOA), which can enhance atmospheric oxidation, promote the formation of secondary pollutants, and affect regional air quality and human health. In order to gain insights on VOCs characteristics and their potentials for O3 and SOA formation, the volume fraction of 102 VOCs in autumn and winter in the urban area of Tongchuan were monitored using the TH-300B online monitoring system. The maximum incremental reactivity (MIR) coefficient and the fractional aerosol coefficient (FAC) were used to estimate the ozone formation potential (OFP) and SOA formation potential (SOAFP), respectively. The φ(TVOC, total VOCs) were (50.52±16.81)×10-9 in autumn and (63.21±35.24)×10-9 in winter. The OFPs were 138.43×10-9 in autumn and 137.123×10-9 in winter, and the SOAFPs were 3.098 μg·m-3 and 0.612 μg·m-3, respectively. Alkanes (26.19%) and aromatics (26.04%) were the most abundant species in autumn, and alkanes (48.88%) were the most abundant species in winter. Trans-2-pentene, toluene, and m/p-xylene were the most reactive species in terms of OFPs in autumn, and ethylene, acetylene, and propylene were the top three species contributing to the total OFPs in winter. Toluene, m/p-xylene, and ethylbenzene contributed the most to the total SOAFPs in both of autumn and winter. Traffic emissions were considered as the major source of VOCs in both seasons. VOCs from biomass/coal combustion emissions showed seasonal differences, which were more prominent in winter. The results can provide references for the "one city, one policy" to mitigate regional VOCs pollution and improve ambient air quality.

Zooplankton community structure and influencing factors in Weihe River mainstem and its tributaries from the northern foot of Qinling Mountains

浮游动物作为食物链中重要的初级消费者，其群落结构特征是水生态系统健康评价的重要指标之一. 本研究于2017年秋季和2018年春季对渭河干流及秦岭北麓五条典型支流开展了系统的水环境及浮游动物群落调查. 结果表明，渭河干流营养盐浓度整体高于秦岭北麓支流，干流浊度远高于支流. 两次调查共鉴定出浮游动物种类数136种(原生动物65种，轮虫44种，枝角类15种，桡足类12种)，其中2017年秋季渭河干流浮游动物种类数、密度和生物量分别为14种、9.02 ind./L和0.0051 mg/L，秦岭北麓支流为37种、42.78 ind./L和0.0229 mg/L；2018年春季渭河干流浮游动物种类数、密度和生物量分别为52种、292.89 ind./L和0.1734 mg/L，秦岭北麓支流为68种、70.15 ind./L和0.0508 mg/L. 秋季渭河干流下游浮游动物种类数、密度和生物量最低，而春季随上、中、下游三者均依次增大；秋季秦岭支流中罗敷河浮游动物密度和生物量最高，而春季灞河最高. 春、秋两季干支流间浮游动物优势种差异较小，但秋季优势种种类数少于春季. 秋季渭河干流中游Shannon-Wiener指数、物种丰富度指数和物种均匀度指数最高，而春季下游最高；秋季秦岭北麓支流石堤河3个指数均最高，而春季灞河Shannon-Wiener指数和物种均匀度指数最高，石堤河物种丰富度指数最高. 典范对应分析表明渭河干流与秦岭北麓支流浮游动物群落结构主导因素均存在季节差异. 本研究揭示了渭河干流与秦岭北麓典型支流的浮游动物群落特征及其影响因素，可为渭河流域环境监测和生态保护提供数据支撑.;Zooplankton is an important primary consumer in the food chain, and its community structure is one of the important indicators for the health evaluation of aquatic ecosystems. A systematic survey of water environment and zooplankton was carried out in the Weihe River mainstem and its five tributaries from the northern Qinling Mountains during autumn 2017 and spring 2018. The nutrient concentrations of the Weihe River mainstem were higher than those of the five tributaries, while turbidity of the mainstem was 10-100 times higher than those of the tributaries. A total of 136 species of zooplankton (65 species of protozoa, 44 species of rotifers, 15 species of cladocerans, and 12 species of copepods) were identified in the two surveys. Among them, the number, density and biomass of zooplankton in the mainstem of the Weihe River mainstem in autumn 2017 were 14 species, 9.02 ind./L and 0.0051 mg/L, while tributaries were 37 species, 42.78 ind./L and 0.0229 mg/L, respectively. The number of species, density and biomass of zooplankton in the Weihe River mainstem in spring 2018 were 52 species, 292.89 ind./L and 0.1734 mg/L, while tributaries were 68 species, 70.15 ind./L and 0.0508 mg/L, respectively. In autumn, the number of zooplankton species, density and biomass in the lower reaches of the Weihe River mainstem were the lowest, while those increasing in the rank from upper, middle, to lower reaches of the Weihe River mainstem in spring. The density and biomass of zooplankton in the Luofu River were the highest in autumn, and those in the Bahe River highest in spring. The difference in dominant species of zooplankton between the trunk and tributaries of spring and autumn is relatively small, but the number of dominant species in autumn is less than that in spring. Canonical correspondence analysis revealed seasonal variance in the dominant factors of the zooplankton community structure in the Weihe River mainstem and the five tributaries. This study not only revealed the correlation between zooplankton community structure and environmental factors in the Weihe River mainstem and its five tributaries, but also provided key data for environmental monitoring and ecological protection in the Weihe River Basin.

长山群岛海域真核微藻粒级结构及扇贝摄食选择性

PDF HTML阅读 XML下载 导出引用 引用提醒 长山群岛海域真核微藻粒级结构及扇贝摄食选择性 DOI: 10.5846/stxb202105191311 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 辽宁省‘兴辽英才计划’项目（XLYC1907109）；大连市杰出青年科技人才项目（2019RJ09）；现代农业体系建设专项（CARS-49） Particle size structure of eukaryotic microalgae and feeding selectivity of scallops in the waters of Changshan Islands Author: Affiliation: Fund Project: 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:采用高通量测序-分子鉴定分级技术于2019年对长山群岛全海域真核微藻粒级结构进行了研究。结果发现，春季以中（47%）、小粒级（41%）为主，夏季以小（39%）、大粒级（38%）为主，秋季以大粒级（60%）为主，春、夏、秋季小、中、大粒级微藻比例为42：47：11、39：23：38、22：18：60。小粒级微藻优势种为细小微胞藻（Micromonas pusilla）、融合微胞藻（Micromonas commoda）和金牛微球藻（Ostreococcus tauri），中粒级微藻优势种为剧毒卡尔藻（Karlodinium veneficum）、大粒级微藻优势种为柔弱几内亚藻（Guinardia delicatula）、平野亚历山大藻（Alexandrium hiranoi）、多纹膝沟藻（Gonyaulax polygramma），综合整个真核微藻群落，春季由中粒径的剧毒卡尔藻占据优势（23.9%），夏季由大粒径的平野亚历山大藻占据优势（29.4%），秋季由大粒径的多纹膝沟藻占据优势（66.8%），有毒甲藻在该海域中占有绝对优势，贝毒累积风险较高，小粒径微藻中金牛微球藻和抑食金球藻曾在渤海引发褐潮，潜在威胁该海域贝类养殖业。虾夷扇贝对小粒级和大粒级微藻的选择性较低，对中粒级微藻的选择性较高，尤其对水体中优势种剧毒卡尔藻一直表现出主动选择。光学需氧量、无机氮、溶解氧、石油类及部分重金属Cd、As、Hg影响着整个长山群岛海域真核微藻粒级结构时空演变。 Abstract:The Chang-shan Archipelago is the largest island group in the northern waters of the Yellow Sea. It significantly contributes to local economic development due to its abundant aquatic products. In recent years, economically important shellfish (scallops, oysters, and clams) have exhibited growth retardation, thinning, and increased mortality, which has affected the sustainable and healthy development of fisheries. Marine microalgae are the dominant food source for filter-feeding shellfish; they differ in size, physiological functions, and sedimentation rates, which greatly influence the regional ecosystem food web.The microalgae size-fractions are closely related to the nutrient reserves and healthy growth of filter-feeding shellfish.High-throughput sequencing technology can reveal highly diverse eukaryotic lineages, while significantly reducing the errors associated with species identification, particularly microalgae. Importantly, the microalgae composition can be ascertained at multiple taxonomic levels, including at the species level. However, some questions still remain regarding their quantitative estimates. As the number of rDNA copies varies widely among different eukaryotes, it is difficult to determine the abundance of eukaryotic microalgae from rDNA CN-based inferences in environmental samples. However, related studies have demonstrated a significant positive correlation between rDNA sequence polymorphisms and rDNA copy numbersrate. When the size of the cell varies in a population, the rRNA/rDNA quantity reflects the biomass of that population. In this study, the proportion of rDNA copy numbers of eukaryotic microalgae was used to characterize their size distribution (the proportion of pico-, nano-, and microphytoplankton).In aquatic ecosystems, the factors controlling phytoplankton production and their seasonal successions are the main items of phytoplankton ecology. Several factors are linked to the growth and size-fraction structure of phytoplankton, such as the availability of light, temperature, nutrients, competition, and parasitism.Therefore, phytoplankton structure can be considered an integrator of environmental factors.In this study, we used the high-throughput sequencing method to assess the size-fraction structure of phytoplankton as well as the controlling environmental factors around the Changshan Islands. It showed that the proportion of pico-, nano-, and microphytoplankton was 42:47:39 in spring, 39:23:38 in summer, and 22:18:60 in autumn.Micromonas pusilla, Micromonas commoda, and Ostreococcus tauri were the dominant picophytoplankton; Karlodinium veneficum was the dominant nanophytoplankton; and Guinardia delicatula, Alexandrium hiranoi, and Gonyaulax polygramma were the dominant microphytoplankton around the Changshan Archipelago. Moreover, Karlodinium veneficum, Alexandrium hiranoi, and Gonyaulax polygramma were the dominant species in spring, summer, and autumn, respectively. The Mizuhopecten yessoensis selectivity to small and large microalgae was low, while the selectivity to medium microalgae was high, especially to Karlodinium veneficum, the dominant species in water. Environmental factors such as COD(chemical oxygen demand), DIN(dissolved inorganic nitrogen), DO(dissolved oxygen), Oil, Cd, As, and Hg were significantly related to the growth and size-fraction structure of phytoplankton. In the three seasons, Cd and COD were significantly related to the growth of picophytoplankton biomass; DO, DIN, and Oil were significantly related to the growth of picophytoplankton biomass; and COD, As, and Hg were significantly related to the growth of picophytoplankton biomass. 参考文献 相似文献 引证文献

The association between algae organisms and environmental factors in Hai-tan Strait of Fujian, China

27 points were surveyed, and then algae and seawater samples were collected in Hai-tan Strait. The correlation on HAB (harmful algae blooms) species and environmental factors were studied. Water temperature (T) and salinity (S) ranging from 11.9 °C to 27.8 °C and 20.4 to 33.7 in the year, respectively. Dissolved inorganic nitrogen (DIN) in surface water ranged from 0.098 to 0.776 mg·L−1, PO4-P ranged from 0.0016 to 0.0729 mg·L−1. And Eutrophication index (E) ranged from 0.03 to 13.8, varied different. 102 species of algae belonging to 4 classes and 52 genera were identified. The diversity was increasingly from winter to summer, decreasingly from summer to autumn, highest in summer. 49 species of red tide organisms were found in Hai-tan Strait, main two classes were Bacillariophyta and Pyrrophyta. Ceratium tripos and Noctiluca scintillans were dominant species in spring, Skeletonema costatum was common, and was also mainly HABs dominant species in summer, autumn and winter. Pearson correlation and Canonical correspondence analysis (CCA) showed that environment factors had significant correlation with dominance HABs species in different extent, and the ordination result was that S(Salinity) > T(Temperature) > pH > E(Eutrophication index) > DO(dissolved oxygen) > DIN > PO4-P. Prorocentrum donghaiense, Skeletonema costatum, Noctiluca scintillans and Karenia mikimotoi caused many times red tide in 2011 to 2016. However, Prorocentrum donghaiense and Karenia mikimotoi cell density was low in survey year. North of the strait and east coast of the southern strait were sensitive sea area of red tide. The work highlights for the first time ecological characteristic of HAB was studied in Hai-tan Strait. Further, the data and results of this study will help us to improve efficiency for controlling HAB. Even, it is worthwhile to the management and response to the red tide disaster. Ordination result can also be a good indicator of ecological risk.

Red tide of the Lingulodinium polyedrum (Dinophyceae) in Odessa Bay (Black Sea)

One of the most massive red tides at the Odessa Bay was observed in September October 2020. It was caused by a toxic dinoflagellate Lingulodinium polyedrum (Stein) Dodge. The maximum abundance (56.1 x 106 cells L-1) of L. polyedrum was registered at the Odessa port area on October 6 when a water temperature and a salinity were 19.7°C and 14.3 ‰ respectively. The red tide was so huge and dense that the water glowed at night due to the bioluminescence characteristic of this species. The article briefly describes the history of the study of L. polyedrum in this area and provides a detailed morphological description with original photographs of this species sampled from bloom. We associate the appearance of the red tide with an increased temperature of sea water and air, a high content of nutrients, the presence of viable L. polyedrum cysts, and a slight decrease in salinity in the bay during the period of a mass development of the species in autumn of 2020. The red tide was accompanied by Protoperidinium steini, P. divergens, Prorocentrum cordatum, P. minimum, P. micans, Gonyaulas scrippsae, Diplopsalis lenticula, Azadinium spinosum, Dinophysis rotundata, D. acuminata, Oblea rotunda, Scrippsiella trochoidea, Ceratium furca.

Canopy spectral characteristics of typical invasive and native plants in the coastal wetland of Yancheng City, China

Spartina alterniflora (S. alterniflora) is a dominant invasive alien species that occurs in Yancheng Wetland National Nature Reserve, the largest coastal wetland in China. It expands rapidly and exerts great threats to local ecosystem. The main native species there are Phragmites australis (P. australis) and Suaeda salsa (S. salsa), respectively. In order to monitor their dynamics, it is of great significance to analyze their spectral discrimination. Canopy spectra of these typical species were measured in July and October in order to compare species differences, as well as the seasonal variation. The Normalized Difference Vegetation Index (NDVI) was calculated based on canopy spectra. The significances of differences in spectral characteristic among species were tested using the one-way analysis of variance (ANOVA) (P < 0.05). The results showed that the visible (VI) bands were the optimum wavelengths for species discrimination in both seasons. S. alterniflora always had the greatest green peak height and red absorption depth. S. salsa had no obvious green peak, but an obvious red reflection peak. P. australis generally had intermediate values. Spectra in the near-infrared (NIR) bands were not appropriate for delineating S. alterniflora and P. australis in summer, as they showed similar values in these wavelengths. But NIR bands could be used to distinguish S. salsa in summer, as it had significantly lower reflectance in NIR bands than the others. Meanwhile, the reflectance in short-wavelength infrared (SWIR) bands became another suitable approach for distinguishing species in autumn. S. salsa had significantly higher values than the others in SWIR regions. Significant NDVI differences between different species proved that it could improve the species discrimination. S. alterniflora always had the highest NDVI values, while S. salsa had the lowest values. The seasonal trend of canopy spectra was also revealed. With plant maturity, the reflectance values in green bands and NIR bands decreased significantly, but increased significantly around the yellow-red wavelengths. The green peak heights, red absorption depths, and NDVI values of the species decreased remarkably. Furthermore, S. alterniflora and P. australis illustrated obvious ‘blue shift’ of the red edge with senescence. These results pointed out the the potential bands and appropriate spectral parameters appropriate for species discrimination, and highlighted the influence of seasonality on spectral information. They provided an important basis for salt marshes identification and dynamic monitoring on a large scale.

Lignocellulosic Biomass Production and Persistence of Perennial Grass Species Grown in Mediterranean Marginal Lands

Biomass production in marginal lands represents one of the most challenging and promising alternatives to sustainably produce biofuels. Native species seem to be the most adequate option to obtain a profitable output when low-input techniques are applied, and biomass is grown in depleted soils and harsh climatic conditions. In this study, a 5-year field trial in the island of Majorca served to investigate different autochthonous and naturalized Mediterranean perennial grasses as novel candidate lignocellulosic bioenergy crops for the semi-arid Mediterranean area and compare them with commercial ones (both Mediterranean and non-Mediterranean). Species and growing season had a significant effect on biomass production, perennialism and biomass quality. Arundo donax (winter crops) and Piptatherum miliaceum (autumn crops) performed better than the commercial species tested (Panicum virgatum for winter crops and Festuca arundinacea for autumn crops) in biomass production and perennialism. In terms of biomass quality, Panicum virgatum was the best species, having high structural content (mainly cellulose and hemicellulose), low non-structural content and the lowest ash. However, Ampelodesmos mauritanicus and Arundo donax rendered similar results, with no significant difference in terms of cellulose production for this latter but with higher lignin content. For the autumn species, Festuca arundinacea was the species with the best biomass quality but with the highest ash production for all the species considered. Hence, both for winter or autumn regimes, native or naturalized plants seem to be better suited than the commercial commonly used for biomass production with energy-producing purposes. Further research must be conducted in terms of seed biology and physiology, seedbed preparation methods, sowing time, seedling density and weed control before they can firmly be proposed as adequate alternatives for energy purposes.

Community structure and diversity of macrobenthos in Jiaozhou Bay

To understand the current community structure and diversity of macrobenthos in Jiaozhou Bay, a survey was conducted at eight sampling stations in April, July, and October 2018, as well as January 2019. Eighty-two macrobenthos species were collected, including 30 of Annelida, 21 of Mollusca, 20 of Crustacea, 8 of Echinodermata, and 3 classified as “Others”. Ruditapes philippinarum was a common dominant species in summer, autumn, and winter. The annual average abundance and biomass were 280 ind./m2 and 446.45 g/m2, respectively. Shannon-Wiener diversity varied from 0.09 to 2.45 with an average value of 1.14. Margalef richness was 0.17–2.32 with an average value of 0.89. Pielou evenness was 0.14–1.00 with an average value of 0.71. The seasonal variation patterns of all tested indices were largely the same, with the highest in spring, next highest in winter, and lower in summer and autumn. The diversity at different survey stations varies greatly.

Shrimp community structure and its relationship with environmental factors in the offshore waters of Zhoushan Islands

In order to learn about the condition of shrimp resources in the waters outside Zhoushan Islands, the relationship between shrimp species composition, dominant species, biodiversity, community structure characteristics and environmental factors was analyzed in April (spring) and October (autumn), 2018. The research indicates that:firstly, there are 32 varieties of shrimp in outer waters of Zhoushan Islands, belonging to 10 subjects, 21 genera, 22 species in spring and 29 kinds in autumn. Compared with historical survey results, the number of shrimp species in this sea area has decreased and the trend has slowed down. Secondly, the dominant species changes significantly, with the spring dominant species being <italic>Metapenaeopsis dalei</italic> and <italic>Metapenaeopsis barbata</italic>, which are mainly inhabited in the southeastern sea of the survey area, and the autumn dominant species is <italic>Parapenaeopsis hardwickii</italic> and <italic>Solenocera crassicornis,</italic> which are mainly found in the north and southwest of the survey area. Thirdly, both Shrimp Richness Index (<italic>D</italic>) and diversity index (<italic>H'</italic>) in spring are lower than those in autumn, while uniformity index (<italic>J'</italic>) value in spring is greater than that in autumn. Shrimp is the most abundant in the water depth of 60-70 meters and the uniformity index (<italic>J'</italic>) value is the highest in the water depth zone from seventy to ninety meters. That’s because spring is the breeding season for most shrimps, shrimp mainly spawning grounds and habitats in the near shore waters, when the richness and species diversity of the outer waters are low, and in autumn, with the weakening of Taiwan’s warm currents resulting in a decrease in warm waters, some shrimp species are in the deep waters of the sea that contribute to the richness of species in autumn. In spring, there is more shrimp in this field with better uniformity, and the autumn shrimp in the sea is mostly adults. The hydrologic environment has less influence on it, so the uniformity is lower than that in the bottom. Fourthly, according to cluster analysis and non-measured multi-dimensional scale sequencing analysis, spring at 45 percent of the similar level is divided into 4 communities, while autumn at 60 percent of the similar level is divided into 3 communities. The similarity between the sea communities is lower than the degree of similarity, and the similarity of autumn shrimp communities is higher than that in spring, indicating that the similarity of autumn shrimp species in the waters outside the Zhoushan Islands is higher than that in spring. Spring in the biological volume and species level are lower than those in autumn. The average similarity in the spring group is lower than that in autumn, and the characteristics with the highest similarity contribution rate in the spring and autumn groups are Dai's prawns and Haas imitation prawns, and the inter-group sex of the two seasons is as high as 82.36%, which may be because in the spring and autumn shrimp catches, individual species has a larger amount of each season or a significant advantage in their respective seasons. SIMPER analysis shows that the shrimp with the highest similarity contribution rate in the spring and autumn groups is consistent with the species of each dominant species. The ANOSIM test demonstrates the shrimp community structure is significantly different in the two seasons. fifthly, CCA analysis makes it clear that temperature is one of the main environmental factors affecting the distribution of shrimp in this area. In autumn, the high temperature high saline system impacted by Taiwan's warm currents becomes the main water group factor in the survey area, and the salinity is regulated by the physiological activities of shrimp, such as shrimp metabolism and osmosis pressure regulation, thus influencing the structure of the shrimp community. Salinity only has a significant effect on the structure of shrimp communities in autumn.

The spatial niche and differentiation of major fish species in the waters east of the Zhoushan Islands in spring and autumn

Based on data from the fishery resources survey in the waters east of the Zhoushan Islands in April (spring) and October (autumn) in 2018, the index of relative importance was used to determine the importance of various fish species in the survey area. The niche breadth and overlap of major fish species were examined using the mean crowding, Shannon, and Pianka indices. Our results showed that there were 10 and 12 major fish species in spring and autumn, respectively. The niche breadth of major fish species in spring and autumn were 0.06–2.01 and 0.34–2.19, respectively, indicating differences between the two seasons. <italic>Larimichthys polyactis</italic> was the only wide-niche species (<italic>B</italic>_{<italic>i</italic>}≥2.0) in spring, whereas four were found in autumn: <italic>Johnius grypotus</italic>, <italic>Miichthys miiuy</italic>, <italic>Larimichthys polyactis,</italic> and <italic>Amblychaeturichthys hexanema</italic>. There were six medium-niche species (2.0&gt;<italic>B</italic>_{<italic>i</italic>}≥1.0) in both spring and autumn, whereas there were three narrow-niche species (1.0&gt;<italic>B</italic>_{<italic>i</italic>}&gt;0) in spring and two in autumn. The degree of niche overlap was unbalanced in the two seasons. There were 20 pairs of species with significant overlap in the spring niche, accounting for 44.44% of the total number of pairs, with a relatively high degree of overlap. Conversely, the major fish species overlap in autumn was low, with 16 pairs of species with significant overlap, accounting for only 24.24% of the total number of pairs. Redundancy analysis (RDA) showed that temperature and salinity were the factors directly affecting the distribution of the major fish species, though depth was also an important factor affecting the obvious niche differentiation of major fish species in spring and autumn.

盐城沿海海堤林带柳莺属(Phylloscopus)鸟类秋季迁徙规律

江苏盐城沿海具有广阔的平原与湿地滩涂，但缺少自然林地。经过多年的防风林建设，沿海海堤逐渐形成了特有的、南北走向的条带林生境，为迁徙鸟类提供了通道和停歇地，是研究鸟类迁徙规律的理想地点。柳莺属鸟类个体小，野外种类识别难，其迁徙规律缺乏深入研究。分别于2018年和2019年两个秋季，采用雾网法对盐城沿海海堤林带柳莺属鸟类的迁徙规律进行研究。结果表明：两个秋季共捕获柳莺属鸟类8种608只，其中极北柳莺（Phylloscopus borealis）、冕柳莺（P. coronatus）、淡脚柳莺（P. tenellipes）和黄眉柳莺（P. inornatus）的捕获数量分别为245只、131只、107只和94只，占捕获总数量的95%，是秋季迁徙期的优势种。对优势种柳莺日捕获率进行比较：2019年极北柳莺的日捕获率显著高于淡脚柳莺和黄眉柳莺（U test，P<0.05）。对捕获数量随时间变化进行分析，4种柳莺都以集中在短时间内快速通过的迁徙策略穿越盐城沿海海堤林带，符合秋季小型雀形目鸟类迁徙采取时间最小化假说。不同种类的柳莺在通过盐城沿海海堤林带的时间顺序上存在显著差异（K-W test，P<0.05），2018年和2019年均以黄眉柳莺通过最晚。随着时间的推移，四种柳莺的脂肪度都逐渐下降。繁殖地纬度的差异可能是导致4种柳莺通过盐城沿海海堤林带时间差异的原因。盐城沿海海堤林带为柳莺属等雀形目小型鸟类的迁徙提供了非常理想的迁徙通道，应当加强海堤林带在鸟类迁徙和保护中的作用研究。;There are vast plains and wetlands in the coastal area of Yancheng City, Jiangsu Province, China, but there lack natural forest lands. After several decades of construction, the Yancheng coastal seawall forests have formed a very unique habitat with north-south direction narrow forest belts. These forest belts have been served as important migrating channels or stopover sites for long-distance migratory birds. Therefore, an ideal place for the study of bird migration has been provided in this site. However, due to the small body size of warblers, it is difficult to identify them in the field which limits our understanding of their migration patterns. Here, by using mist-nets, we collected eight dominant migratory warbler species in autumn in 2018 and 2019, and studied the temporal rhythm of their migration. In total, 608 warblers belonging to 8 species were captured by using mist-nets in autumn in 2018 and 2019, including 245, 131, 107 and 94 individuals for Phylloscopus borealis, P. coronatus, P. tenellipes and P. inornatus, respectively. The total captured number of these four species accounted for 95% of all the captured warblers, indicating that they were the dominant migratory warbler species in this study site in autumn. The daily captured number of P. borealis in 2019 was significantly higher than those of P. tenellipes and P. inornatus (U test, P<0.05). Based on the changing of captured number with time, all these four dominant warblers tended to adopt the migration strategy that pass through the study site rapidly in a concentrated time. This is consistent with the hypothesis that small passerines usually choose time minimizing strategies to get to the winter sites as soon as possible in autumn. There was a significant difference in the temporal rhythm of the four warbler species in both years (K-W test, P<0.05). The warbler P. inornatus was the last one that passed through the study site both in 2018 and 2019. The fat scores of all the four warbler species significantly decreased with the migration time. We consider that the differences in the temporal rhythm of the four warbler species might attribute to the differences in the geographic locations of their breeding sites. In conclusion, the Yancheng seawall forest belt provided an appropriate migration channel for small passerines such as the warblers. More studies should be conducted to explore the important roles of the Yancheng seawall forest belts for bird migration and conservation in the future.

Sex, age, molt strategy, and migration distance explain the phenology of songbirds at a stopover along the East Asian flyway

Sex- and age-specific differences in the timing of migration are widespread among animals. In birds, common patterns are protandry, the earlier arrival of males in spring, and age-differential migration during autumn. However, knowledge of these differences stems mainly from the Palearctic-African and Nearctic-Neotropical flyways, while detailed information about the phenology of migrant birds from the East Asian flyway is far scarcer. To help fill parts of this gap, we analyzed how migration distance, sex, age, and molt strategy affect the spring and autumn phenologies of 36 migrant songbirds (altogether 18,427 individuals) at a stopover site in the Russian Far East. Sex-differential migration was more pronounced in spring than in autumn, with half of the studied species (6 out of 12) showing a protandrous migration pattern. Age-differences in migration were rare in spring but found in nearly half of the studied species (11 out of 25) in autumn. These age effects were associated with the birds’ molt strategy and the mean latitudinal distances from the assumed breeding area to the study site. Adults performing a complete molt before the onset of autumn migration passed the study site later than first-year birds undergoing only a partial molt. This pattern, however, reversed with increasing migration distance to the study site. These sex-, age-, and molt-specific migration patterns agree with those found along other flyways and seem to be common features of land bird migration strategies.Significance statementThe timing of animal migration is shaped by the availability of resources and the organization of annual cycles. In migrant birds, sex- and age-differential migration is a common phenomenon. For the rarely studied East Asian flyway, we show for the first time and based on a large set of migrant songbirds that earlier migration of males is a common pattern there in spring. Further, the timing and extent of molt explained age-differential migration during autumn. Adults molting their complete plumage at the breeding area before migration showed delayed phenology in comparison to first-year birds, which perform only a partial molt. This pattern, however, reversed with increasing migration distance to the study site. Since our results agree with the general patterns from the other migration flyways, similar drivers for differential migration may act across different flyway systems, provoking a similar evolutionary response.

Aspects of the feeding ecology of introduced Rose-ringed Parakeets Psittacula krameri in the urban landscape mosaic of Durban, KwaZulu-Natal Province, South Africa

The Rose-ringed Parakeet Psittacula krameri is one of the world’s commonest invasive bird species and has established in the South African urban landscapes. However, relatively little is known about the feeding biology of parakeets here. We surveyed areas in eThekwini Municipality, Durban, South Africa, to determine their feeding sites and the related land-use types. Patterns of the association were explored using Correspondence Analysis to determine parakeets’ diet across seasons and interaction between different tree species fed on by parakeets and other bird species. Dietary items were determined visually using binoculars. We identified a total of 63 feeding sites with many in the urban built land-use cover type. The parakeets’ diet differed significantly across the seasons with spring accounting for 33% of annual food items. We identified 31 fruiting/flowering tree species fed on by the parakeets, with fleshy fruits and flowers accounting for 58% and 19%, respectively. Native tree species (63%) were mostly relied on when compared with non-native (27%). They also fed on carpenter ants Camponotus cinctellus which contributed 3% of their diet. The forest fever-berry Croton sylvaticus (fleshy fruits) and African star-chestnut Sterculia africana (flowers) were the most preferred tree species in autumn and summer. The observed number of bird species that communally fed with parakeets were significantly different across the sampled seasons. The diets for the Common Myna Acridotheres tristis and the Speckled Mousebird Colius striatus overlapped with parakeets for most tree species. Parakeets were observed actively feeding in the early mornings and late afternoons before roosting. Our study supports that parakeets are generalist-opportunistic feeders. The assessment of Rose-ringed Parakeets feeding ecology may help understand their potential impact on native tree and bird species within an urban landscape.

Transcontinental 2200 km migration of a Nathusius’ pipistrelle (Pipistrellus nathusii) across Europe

Abstract A male Pipistrellus nathusii ringed in Pape Natural Park (S Latvia) in August 2015 was recovered recently dead in Pitillas’ Lagoon Natural Reserve (N Spain) in March 2017. At 2224 km in SSW direction, this is the first documented bat migration between these countries and worldwide the longest migration record of a bat. We also report other observations of this species in autumn in Northern Spain, suggesting that the Iberian Peninsula may be an important wintering area for Nathusius’ pipistrelles. Conservation measures should be agreed on by countries along the migration routes to improve the protection of this species.

Seasonal Migration in the Aphid Genus Stomaphis (Hemiptera: Aphididae): Discovery of Host Alternation Between Woody Plants in Subfamily Lachninae.

About 10% of aphid species show host alternation. These aphids migrate between primary and secondary host plant species in spring and autumn. Host alternation has not been observed in subfamily Lachninae, although it has been suggested on the basis of circumstantial evidence that Stomaphis japonica (Takahashi) may alternate its host between Quercus serrata (Murray) and Quercus acutissima (Carruth). However, a molecular phylogenetic study has indicated that the Stomaphis individuals feeding on these two plant species belong to two different lineages and aphids feeding on Q. acutissima and Pinus densiflora (Sieb. & Zucc.) belong to the same lineage. Here, we examined host alternation in Stomaphis species by comparing molecular phylogenetic identities, morphological features, and life cycles. The molecular analysis and morphological examination showed that aphids feeding on Q. acutissima were the same as those feeding on P. densiflora, whereas aphids feeding on Q. serrata were different from those feeding on Q. acutissima or on P. densiflora. Furthermore, winged aphids were observed on both Q. acutissima and P. densiflora in autumn, but we did not observe winged aphids on Q. serrata. These results indicate that Stomaphis (Walker) individuals feeding on Q. serrata and Q. acutissima belong to two species, one that feeds year-round on Q. serrata, and another, heteroecious species that feeds on P. densiflora as a primary host and on Q. acutissima as a secondary host. This study documents host alternation in subfamily Lachninae for the first time and discusses the acquisition of host alternation by Stomaphis from evolutionary and ecological perspectives.

Investigating effect of climate warming on the population declines of Sympetrum frequens during the 1990s in three regions in Japan

Climate warming is of concern as a key factor in the worldwide decline in insect populations. In Japan, numbers of a common dragonfly in rice paddy fields, Sympetrum frequens, decreased sharply in the 1990s. Because S. frequens migrates to cooler mountains in summer, climate warming has been suggested as one of the main causes of the population decline in addition to agronomic factors. Here, we analysed the relation between summer temperatures and population densities of S. frequens and the related S. infuscatum, which does not migrate to mountains in summer, using published population monitoring data and temperature data from three regions (Toyama, Ishikawa, and Shizuoka) in Japan. Decadal differences in summer temperatures lay within the range of fluctuations among years, suggesting that an increase in summer temperatures cannot explain the past sharp population declines. However, regression analyses using monitoring data from Toyama showed that the population dynamics of both species in autumn are negatively correlated with summer temperatures in the same year. These results suggest that high temperatures in summer directly affect adult mortality to an extent that results in a decrease in population growth.

Winter Geometrid Moths in Oak Forests: Is Monitoring a Single Species Reliable to Predict Defoliation Risk?

Species within the group of winter moths (Geometridae) are important oak defoliators in European forests. Adults of these species emerge either in late autumn (‘autumn species’) or in early spring (‘spring species’), and caterpillars of both ‘autumn’ and ‘spring’ species appear in spring. The abundance of adults assessed by regular monitoring allows the prediction of the defoliation intensity in trees by caterpillars in the following spring. ‘Autumn species’ (mostly a single one, Operophtera brumata) are monitored by forestry practices as pests, whereas ‘spring species’ are often not paid any attention. We hypothesised that ‘spring species’ could also have an important share in caterpillar assemblages in oak forests. We aimed to study the proportions between ‘autumn’ and ‘spring’ species in adult and larval stages. In a xeric thermophilous oak forest in southern Slovakia, Central Europe, we collected adult moths using sticky bands set up on trunks of Quercus pubescens during the winter of 2014–2015 and caterpillars from other trees belonging to the same oak species over the following spring. We also captured caterpillars from several oak species in various areas and over different years in Slovakia and Bulgaria, and we compiled relevant literature data. ‘Spring species’ recorded from a unique forest as adults during winter and as caterpillars in the following spring were significantly more abundant than ‘autumn species.’ Moreover, ‘spring species’ from Slovakian forests, regardless of the locality, the oak species and the year of sampling, reached high proportions, mostly over 50% of individuals in caterpillar assemblages. The ‘spring species’ Agriopis leucophaearia was the most abundant, followed by the ‘autumn species’ Operophtera brumata. ‘Spring species’ accounted for more than 50% of individuals in caterpillar assemblages in the Balkan Peninsula (Bulgaria) concerning one case, and they were of little importance in northern Greece. We recommend monitoring all winter moth adults (‘autumn’ and ‘spring’ species together) continuously in forestry practices, using sticky bands on oak trees from late autumn to early spring.