Patterns of waterbird community composition across a natural and restored wetland landscape mosaic,Yellow River Delta,China

Habitat restoration can help mitigate the extensive loss and degradation of estuarine and coastal wetlands that have consequently eroded the integrity of many migratory flyways and wintering habitat for waterbird populations. Assessing the impact of restoration strategies however relies on empirical data on waterbird community distribution patterns across natural and restored wetland components. We conducted habitat and waterbird surveys across six natural and restored wetland regions in the Yellow River Delta Nature Reserve (YRDNR), eastern China, between 2007 and 2009. We recorded 93 waterbird species, including populations of 21 global conservation importance species. Community composition was stratified into distinctive clusters with compositional structure changing across these natural, modified and restored wetland components. NMDS ordination revealed that waterbird communities in restored wetlands were significantly different from those in natural and modified wetland components. Community distribution patterns were strongly influenced by environmental gradients (most noticeably salinity), water-level regulation, vegetation composition and differences in protected status. We found marked temporal patterns in waterbird community composition, which may be predictable for the different wetland components across the YRDNR landscape. Our study highlights the conservation benefits of restoring smaller wetland components in improving the ecological integrity of the wider wetland landscape mosaic for waterbird populations. A more coherent and intensive landscape management of water-level regulation and restoration of salinity gradients will be fundamental for wetland and waterbird conservation throughout the YRDNR.     

A diagnostic modelling framework to construct indices of biotic integrity: A case study of fish in the Zeeschelde estuary (Belgium)

We propose a coherent regression model building framework to construct fish-based indices. More specifically, we concentrate on the selection of an optimal set of metrics which remains a difficult problem. The paper departs from the observation that an index of biotic integrity (IBI) is analogous to a diagnostic model in medicine assessing the health condition of a patient from a series of biomarkers. In the same vein, an IBI is a diagnostic model predicting the ecosystem condition of a site from a set of (scored) metrics. Metrics are community attributes sensitive to anthropogenic pressure and their scores express the “distance to target” to a reference condition. In a medical context, Receiver Operating Characteristic (ROC) curves are commonly used to assess the diagnostic accuracy of laboratory tests. An ROC curve plots the sensitivity of a test (Se; the capacity to detect a disease or degradation) as a function of its false positive fraction (FPF) which is the complement of the specificity (Sp = 1 - FPF; the capacity to recognise a healthy person or a reference condition). The ROC curve represents the strength of the index to discriminate between degraded and reference sites. Higher curves correspond to stronger tests as then a higher sensitivity can be combined with a lower false positive fraction. Hence, it is intuitively clear to use summary statistics of the ROC curve as criteria to optimise medical tests or biotic indices. In this paper, we illustrate the value of this modelling framework with a case study in the Zeeschelde estuary in Belgium. In essence, a “traditional” IBI is an average of metrics scoring relevant properties of the ecosystem. We demonstrate this average score model (AVG) is a special member of the more flexible predictive logistic model (PLM) family. The selection of a set of metrics becomes equivalent to variable selection in statistical model building. We apply model building techniques as best subsets regression to facilitate the search for an optimal suite of metrics from a candidate set and use cross-validation to avoid overfitting. The results show that a few metrics suffice to discriminate between most-impacted and least-impacted sites.     

Diet of mid-Atlantic Sowerby's beaked whales Mesoplondon bidens

The first mid-Atlantic diet of Mesoplodon beaked whales is presented, from ten Sowerby's Mesoplodon bidens stranded in the Azores region between 2002 and 2009. This doubles the worldwide number of stomachs sampled, and reveals new feeding habits for this species. The mean number of prey items per stomach was 85±89 (range: 12–238), with fish accounting for 99.3% and cephalopods contributing less than 1% of total prey. Fish otoliths from 15 families and cephalopod lower mandibles from three families were identified, representing 22 taxa. The diet consisted mainly of small mid-water fish, the most numerous being Diaphus sp., Lampanyctus sp. and Melamphaidae species. Myctophids were present in all stranded individuals, followed by Diretmidae, Melamphaidae and Opisthoproctus soleatus, while the remaining fish species were scarce or single occurrences. Consistency of diet in four different years reveals a divergence from all previous records in continental areas, where mainly neritic and shelf-break benthopelagic fish species have been reported. Mid-Atlantic Sowerby's beaked whales' showed dietary plasticity, feeding on the most abundant mid-water groups occurring between 0 and750 m. Trophic level from prey numerical frequency was estimated at 4.4±0.46.     

Species composition and diversity of pelagic fishes based on a longline fishery catch in the North Pacific Ocean

Evaluation of spatial-temporal variability of species composition and diversity in oceanic ecosystems is not easy because it is usually difficult to obtain sufficient data quantifying such variability.In this study,we examined pelagic species diversity indicators,species richness,Shannon-Wiener index of diversity and Hurlbert's species evenness,for fish assemblages from two areas(north and south) in the North Pacific Ocean(2°±12°N,178°E±165°W) during May±July 2008.The assemblages were based on data collecte...     

大亚湾春秋季鱼类种类组成及年龄结构分析

2006年4月和9月对大亚湾海域通过拖网和流刺网捕获的鱼类进行初步调查.结果表明,渔获物中出现18目76科135属200种鱼类,其中软骨鱼纲4目5科5属6种,占调查鱼类总种数的3.0%;硬骨鱼纲14目71科130属194种,占调查鱼类总种数的97.0%.根据其适温类型可分为暖水性种、暖温性种和冷温性种,其中暖水性鱼类有183种,占总种数的91.5%;暖温性鱼类有16种,占总种数的8.0%;冷温性鱼类仅有1种,占总种数的0.5%.渔获物中底层和近底层鱼类占多数,其中,底层鱼类共有74种,占总种数的37.0%;近底层鱼类共有68种,占总种数的34.0%;中上层鱼类共有45种,占总种数的22.5%;岩礁鱼类有13种,占总种数的6.5%.大亚湾鱼类的年龄普遍偏低,以1 a龄鱼为主.与相邻海区鱼类区系特征比较,大亚湾海域具有我国热带和亚热带性海湾的鱼类区系特征.     

Habitat suitability assessment of endangered plant Tetraena mongolica Maxim.

This paper uses Landsat TM images, GIS technology, Digital Elevation and Habitat Assessment Models to assess the habitat suitability of the endangered plant Tetraena mongolica in western Ordos Plateau of China by selecting terrain, soil, climate, and human activity factors as assessment indices. The results are as follows: natural factors such as climate and terrain are not restrictive factors for the survival and development of T. mongolica in the research region, whereas human activity causes habitat quality of T. mongolica to change intensively in quantity and distribution. The area of less suitable habitat increased by 23.87 km² compared to potential habitat suitability. Thus, in some areas, human activity may be a key factor causing the endangerment of T. mongolica. There were obvious differences of potential and practical habitat suitability between different habitat regions in the study area. The habitat quality was better in Wujiamiao, Dishan and Qipanjing regions, and worse in Wuda and Qianlishan regions.     

罗非鱼下脚料自溶条件的初步探讨

采用单因素和正交优化实验L9(43)确定酶法自溶罗非鱼下脚料的最适条件,结果表明,最适自溶条件为:料液质量比1∶3,反应温度50℃,pH7.5,反应时间6.5h;酶解结束蛋白质回收率为81.75%。     

金枪鱼油的精炼工艺对脂肪酸组成的影响

粗鱼油通过精炼可以除去非甘油三酯杂质成分,研究表明黄鳍金枪鱼鱼油精炼的工艺参数为:800 g/L的H3PO4脱胶,添加量为油量的1%(体积分数);300 g/L的NaOH脱酸,添加量为油量的2%(体积分数);活性土脱色,添加量为油量的10%(质量分数);85℃下减压蒸馏脱臭15 min。经过精炼,鱼油呈淡黄色,澄清透明,有淡鱼腥味,理化指标达到鱼油SC/T3502-2000标准的精制鱼油一级要求,精制鱼油中PUFA的总含量(w)达37.06%,DHA和EPA含量(w)分别为25.10%和4.45%。     

鱼汁、海泥抽出液和人尿对小环藻生长的影响

在室内条件下，通过单因子实验和正交实验的方法，研究了鱼汁、海泥抽出液和人尿对小环藻（Cyclotella sp．）种群生长的影响。结果表明，350mL的培养体积下，当鱼汁添加量为20mL时，小环藻生长效果最好，相对生长率（K）较对照组升高了33．3％，平均倍增时间（G）降低了34．9％，但随着浓度升高，藻细胞开始出现死亡。海泥抽出液添加量为20mL时，K值最大，较对照组增加35．6％，G值下降了25．15％。人尿添加量为10mL时，K值最大，较对照组增加17．9％，G值下降了15．77％。统计分析表明，鱼汁、海泥抽出液和人尿对小环藻实验种群的生长均有极显著影响。海泥抽出液对小环藻影响大，其次是鱼汁和人尿。正交实验表明，在鱼汁、海泥抽出液和人尿的添加量分别为2．5、15．0和1．0mL的组合实验组，小环藻的生长效果最好。     

SERUM IMMUNOGLOBULIN OF THE MANDARIN FISH,SINIPERCA CHUATSI WITH DEVELOPMENT OF POLYCLONAL ANTIBODY

Serum immunoglobulin from the mandarin fish,or the so-called Chinese perch,Siniperca chuatsi(Basilewsky),was successfully purified using affinity chromatography.Heavy and light chains were detected on electrophoresis gel,with molecular weights being estimated at 72 and 29 kDa,respectively.The tetrameric IgM of S.chuatsi was calculated to be 808 kDa.The rabbit polyclonal antisera against the purifed immunoglobulin were developed and tested by Westem blot analysis.The antisera reacted strongly with the heavy chains of S.chuatsi immunoglobulin.Humoral immune responses of the mandarin fish can then be examined using the developed polyclonal antibody.