Reproductive effort in relation to maternal social rank in reindeer (<Emphasis Type="Italic">Rangifer tarandus</Emphasis>)

In polygynous mammals, high-quality females may increase their fitness by providing superior care to their offspring. Based on the agonistic interactions of female reindeer in an experimental herd during two consecutive years (1997 and 1998), we tested whether maternal social rank influenced: (1) winter body-mass change of females, (2) preparturition reproductive effort (measured as fecundity, the birth mass and the birth date of their calves), (3) preweaning maternal effort (measured as calves preweaning mortality, early preweaning and late preweaning growth rate and September body mass of calves), and (4) postweaning maternal effort (measured as calves body-mass change during their first winter). In the models, we included September females body mass as a covariate to separate the effects of maternal rank and body mass. We also tested whether the effect of social rank on maternal efforts was dependent on offspring sex. High-ranked females gained body mass whereas low-ranked females lost weight during the winter. Fecundity was higher and date of birth was earlier in high-ranked females than in subordinates, whereas no effect of females rank on birth mass of calves was found. Early preweaning growth rate and September body mass of calves increased with increasing females social rank, whereas late preweaning daily growth rate of calves was not influenced by females rank. Calves preweaning mortality was only influenced by year, which also explained most of the variance in the winter body-mass change of calves. The effects of females rank on the reproductive-efforts parameters studied were not specific to offspring sex. These findings suggest that females rank influences reproductive effort during the preparturition, as well as the preweaning, period, the effect being sex independent.Communicated by R. Gibson     

星云湖底质中重金属与营养元素的分布特征及关联性分析

介绍了星云湖底质调查工作概况,统计和讨论了结果,并分析了关联度.     

2013-2015年十堰市环境空气质量变化趋势分析研究

利用十堰市空气自动监测站的监测数据,采用综合指数、空气质量指数(AQI)和Spearman秩相关系数法等评价方法,研究十堰市2013年-2015年环境空气质量变化情况及其影响因素,为城市的大气污染防治提供治理思路.结果表明:2013年-2015年十堰市城区空气质量逐年好转,除PM10和PM2.5外,其他因子均达标,污染物贡献比例中,PM10和PM2.5污染负荷占比超过50%,为主要污染物;十堰市城区空气质量整体呈夏季较好,冬季较差的趋势;全市中开发区铁二处空气质量较好,张湾区刘家沟空气质量较差;结合自然因素和人为因素,综合分析空气质量的变化情况,通过调整能源结构、减少污染源排放和使用清洁能源等多项措施,并注意季节特征和加强预警预报工作,进而改善空气质量.     

Estimating Effects of Tidal Power Projects and Climate Change on Threatened and Endangered Marine Species and Their Food Web

Marine hydrokinetic power projects will operate as marine environments change in response to increased atmospheric carbon dioxide concentrations. We considered how tidal power development and stressors resulting from climate change may affect Puget Sound species listed under the U.S. Endangered Species Act (ESA) and their food web. We used risk tables to assess the singular and combined effects of tidal power development and climate change. Tidal power development and climate change posed risks to ESA‐listed species, and risk increased with incorporation of the effects of these stressors on predators and prey of ESA‐listed species. In contrast, results of a model of strikes on ESA‐listed species from turbine blades suggested that few ESA‐listed species are likely to be killed by a commercial‐scale tidal turbine array. We applied scenarios to a food web model of Puget Sound to explore the effects of tidal power and climate change on ESA‐listed species using more quantitative analytical techniques. To simulate development of tidal power, we applied results of the blade strike model. To simulate environmental changes over the next 50 years, we applied scenarios of change in primary production, plankton community structure, dissolved oxygen, ocean acidification, and freshwater flooding events. No effects of tidal power development on ESA‐listed species were detected from the food web model output, but the effects of climate change on them and other members of the food web were large. Our analyses exemplify how natural resource managers might assess environmental effects of marine technologies in ways that explicitly incorporate climate change and consider multiple ESA‐listed species in the context of their ecological community. Estimación de los Efectos de Proyectos de Energía de las Mareas y el Cambio Climático sobre Especies Marinas Amenazadas y en Peligro y su Red Alimentaria     

Assessment of impacts of invasive fishes on the food web structure and ecosystem properties of a tropical reservoir in India

A network model of trophic interactions in a tropical reservoir in India was developed with the objective to quantify matter and energy flows between system components and to study the impact of invasive fishes on the ecosystem. Structure of flows and their distribution within and between trophic levels were analysed by aggregating single flows into combined flows for discrete trophic levels. The trophic flows primarily occurred in the first four trophic level (TL) and the food web structure in this reservoir ecosystem was characterized by the dominance of low TL organisms, with the highest TL of only 3.57 for the top predator. Highest system omnivory index (SOI) was observed for indigenous catfishes (0.422), followed by the exotic fish Mozambique Tilapia (0.402). Nile Tilapia and Pearl spots show the highest niche overlap which suggests high competition for similar resources. The mixed trophic impact routine reveals that an increase in the abundance of the African catfish would negatively impact almost all fish groups such as Indian major carps, Pearl spots, indigenous catfishes and Tilapines. The other invasive fish Mozambique Tilapia adversely affects the indigenous catfishes. The most interesting observation in this study is that the most dominant invasive fish in this reservoir, the Nile Tilapia does not negatively impact any of the fish groups. In fact it positively impacts the Indian major carps. The direct and indirect effects of predation between system components (i.e. fish, invertebrates, phytoplankton and detritus) are quantitatively described and the possible influence and role in the ecosystem's functioning of the invasive fish species are discussed.     

Influence of Care of Domestic Carnivores on Their Predation on Vertebrates

Abstract: Domestic dogs (Canis familiaris) and cats (Felis catus) are the most abundant mammalian carnivores worldwide. Given that domestic carnivores rely on human‐provided food, their densities are usually independent of prey densities. Nevertheless, underfed pets may need to hunt to meet their energetic and nutritional requirements. We explored the effects of different levels of care (provision of food) of dogs and cats on their predation rates on wild vertebrates in 2 areas of southern Chile. We interviewed cat and dog owners and analyzed prey remains in scats of pets to examine how domestic dogs and cats were managed and to gather information on the wild vertebrates killed and harassed by pets. We used logistic regression to examine the association between pet care and the frequency of wild vertebrate remains in scats. The probability of a dog preying on vertebrates was higher for poorly fed than for adequately fed dogs (odds ratio = 3.7) and for poorly fed than for adequately fed cats (odds ratio = 4.7). Domestic dogs and cats preyed on most endemic and threatened mammals present in the study sites. Our results provide support for the hypothesis that the less care domestic animals receive from owners the higher the probability those animals will prey on wild vertebrates.     

基于ArcGIS的校园景观水体水质特征研究与评价

为了解校园景观水体的水质污染特征及规律,结合富营养化常规监测指标,运用单因子指数法、内梅罗指数法、综合营养状态指数法及基于Arc GIS的空间叠加分析法对重庆某大学校园景观水体(静湖)冬季枯水期的水质状况进行了分析与评价。结果表明,叶绿素a和高锰酸钾指数超标点位为83%和17%;而总氮和总磷能满足地表水环境质量标准中的Ⅳ类与Ⅴ类;叶绿素a与总氮、总磷存在一定的线性关系,且各因子对富营养化的贡献大小为叶绿素a总磷透明度、高锰酸钾指数总氮;该人工湖冬季枯水期综合水质已呈现中度富营养化状态,水质有待改善。     

湖库富营养化状态的快速评价

介绍了实现富营养化评价的EXCEL自定义函数的代码编写、模块保存与导入、函数使用等。以富营养化评价的实例,说明使用自定义函数求解含多参数的复杂计算是很方便的。     

Spatial Distribution of Animals and Variation in Their Trophic Activity Measured Using the Bait-Lamina Test in Sod-Podzolic Soil under a Spruce Forest

The mode of spatial distribution of soil animals and their trophic activity was studied in the sod-podzolic soil under a spruce forest. At the test point level, no apparent relationship between the distribution of soil animals and physicochemical characteristics of the soil was observed. The patterns of distribution of detritophages and the trophic activity (measured using the bait-lamina test) were similar. The perforation of laminae in the bait-lamina test resulted from the trophic activity of both micro- and mesofauna.