基于无线传感网络的海参苗养殖环境监测系统的研究

本文通过分析海参苗养殖现状,设计了一种基于无线传感网络的海参苗养殖环境监测系统。通过在监测区域部署传感器节点,监测养殖池中的的温度、盐度、溶解氧及水位等环境参数。将检测到的数据无线发射到远程监测软件,监测软件将分析结果反馈给末端执行机构,实现对养殖池环境的实时监控。本文从系统结构和数据传输等方面进行了阐述,对海参苗养殖的自动化生产提供了一种有效可行、成本较低的解决方案。     

理性看待当前的蔬菜价格波动

分析了中国当前蔬菜价格低迷的现状,剖析了价格持续走低的原因,展望了后市蔬菜价格的运行趋势,揭示了蔬菜价格波动的合理性,提出应科学、辩证、理性地去认识其波动,使市场在蔬菜资源配置中发挥决定性作用,进而从消费引导、扶持政策、监测预警、产销模式等角度提出相关政策建议。     

National Park stewardship and ‘vital signs’ monitoring: a case study from Channel Islands National Park,California

• 1. Place‐based conservation strategies require that stewards know and understand the targeted ecosystems, restore impaired resources, protect the ecosystems, and connect people wholeheartedly to the places. Knowledge of ecosystem structure and functioning is the cornerstone of stewardship.
• 2. This paper describes the design, implementation, and application of an ecological monitoring programme in Channel Islands National Park, California, USA. Experience from this programme showed that monitoring ecological ‘vital signs’ was a quick, sure, and inexpensive way to discover and track ecosystem dynamics.
• 3. Monitoring ecological ‘vital signs’ determined status and trends of ecosystem integrity and established limits of normal variation of key ecosystem features. It also provided early warnings of situations that required intervention and helped frame research questions to determine chains of cause and consequence.
• 4. The strong influence and probabilistic nature of biological interactions in ecosystems precluded effective use of deterministic modelling to predict ecosystem behaviour accurately. Therefore, ongoing monitoring was required to increase knowledge of system dynamics reliably. The US National Park Service has begun to identify and monitor the ecological ‘vital signs’ in 32 networks of 270 parks.

Published in 2004 by John Wiley & Sons, Ltd.     

Comparison of traditional and environmental DNA survey methods for detecting rare and abundant freshwater fish

1. Detecting rare species is often a necessity for conservation and management, yet challenging for many field survey methods. Environmental DNA (eDNA) is a highly promising solution that has been shown to outperform many established survey methods.
2. Macquarie perch (Macquaria australasica) is an endangered native species that has declined significantly in range and abundance. Detection of M. australasica was compared with an abundant alien fish species (Oncorhynchus mykiss) using eDNA and three conventional survey methods: gill nets, electrofishing and fyke nets.
3. eDNA occupancy estimates for both fish species were compared using four different models to investigate what effect these differences have on false positives and false negatives for the rare and common fish species. These models used unadjusted eDNA detections in water samples, eDNA detections that have been screened using a limit of detection method to remove potential false positives, eDNA data supplemented with a second survey method, or eDNA data augmented with sequencing of positive polymerase chain reaction replicates.
4. eDNA surveying as a single detection method was found to be more efficient and sensitive compared with each capture method separately and combined. Occupancy estimates for the common and rare species did not vary significantly between the four site occupancy-detection models, suggesting that supplementary data may not have as much effect on occupancy estimates compared with other approaches such as temporal or spatial sampling.
5. We conclude that eDNA outperforms the three established survey methods for both a rare and common freshwater fish species. Although there was no significant effect of augmenting eDNA survey methods with other survey data, additional data may improve confidence in detection, and provide confirmatory evidence for unexpected or new detections of a species.

     

Spatial–temporal variations in biosonar activity of Yangtze finless porpoise in the lower reaches of the Yangtze River and its correlation with underwater noise: Are quieter non-shipping branches the remaining shelters?

1. Yangtze finless porpoise (YFP) is Critically Endangered, It relies on its biological sonar sensing system for important life activities. The rapid development of the Yangtze valley has brought busy shipping, which has resulted in increased noise.
2. Two locations on the shipping channel and non-shipping branch were selected. Passive acoustic monitoring was used to record the biosonar signals of porpoises and underwater noise. The number of click trains, echolocation encounters, buzzes and buzz ratios were counted and the root mean square sound pressure level of noise was calculated in five diel phases.
3. A non-parametric test was used to analyse the differences among different phases and between different locations. The aim of the study was to detect the spatial and temporal variations in the biosonar activity of YFPs and underwater noise between non-shipping and shipping channels, and to provide scientific advice for YFP conservation.
4. Significant spatial and temporal patterns were observed both in biosonar activity and noise. Average biosonar activity, including click trains, buzzes, buzz ratio and echolocation encounters, was higher in the non-shipping channel than in the shipping channel, whereas the noise level was higher in the shipping channel than in the non-shipping channel.
5. In the non-shipping channel, the buzz numbers and buzz ratios, indicators of porpoise feeding activity, were higher at night than during the day while the noise level was higher during the day than at night.
6. These findings may be associated with the noise avoidance strategies of YFPs to adapt to the busy shipping on the Yangtze River. Maintaining the non-shipping status of some branches of the Yangtze River can provide more shelters for the YFPs. Strengthening the measures for banning navigation at night or reducing the vessel speed at night throughout the entire year would improve the YFPs’ feeding success.

     

Monitoring Indo-Pacific humpback dolphin occurrences in a highly urbanized estuary for informing conservation and management

1. The estuaries within the Pearl River Delta are sites for large-scale urban development and offshore construction. These projects have conservation stakeholders calling for more protection for the Indo-Pacific humpback dolphins whose habitat overlaps with current and proposed construction sites.
2. Efforts to improve impact assessments are hindered by the lack of baseline data and comprehensive understanding of how often the dolphins are present in areas near or within locations targeted for further development. The Modaomen Estuary within the Pearl River Delta is a good example of this, with little consideration for the dolphins as no data on their diurnal and seasonal occurrences within the estuary exist.
3. A passive acoustic monitoring system was deployed over a calendar year from October 2016 to September 2017 to monitor the presence of humpback dolphins in the Modaomen Estuary.
4. Results indicated that the estuary is an important area for humpback dolphins, with regular diel rhythms and seasonality in detection rates. For example, higher detections were seen during the wet season than during the dry season. However, there was no significant difference in detection rates between the flood and ebb tides, or between high and low tidal phases.
5. Since the Modaomen Estuary is targeted for further development in the near future, these data provide the rationale for resource management and consent processes to consider potential impacts on the dolphins, as well as to aid marine spatial planning and conservation measures.

     

Science and conservation of Amazonian crocodilians: a historical review

1. Crocodilians represent one of the oldest extant vertebrate lineages. They have co-existed with humans throughout the Amazon basin for thousands of years, often having a strong cultural and economic influence on people's lives. Shifts in the socio-economic and political reality of the Amazon basin during the last century have led crocodilian populations to face large variations in their numbers according to different levels of exploitation and strategies for their conservation.
2. This article reviews the scientific knowledge obtained between 1945 and 2019 on the biology, conservation and management for the four Amazonian crocodilian (caiman) species (Caiman crocodilus, Melanosuchus niger, Paleosuchus palpebrosus and Paleosuchus trigonatus). It provides a general overview on past and current population status and research efforts involving caimans in the Amazon basin and discusses perspectives for the future.
3. The most significant studies on the ecology, genetics and management strategies are examined in more detail and this information is contextualized to provide an overview of the most relevant findings that might explain caiman population trends over the last 75 years.
4. Systems for sustainable management in the Amazon basin have been discussed for the past 20 years, but remain rarely applicable. It is necessary to develop new ways to maintain healthy caiman populations through innovative management programmes. Sustainable harvesting of wildlife has been shown to promote conservation targets, especially those initiatives based on community co-management. In this article, we propose some general guidelines for future management schemes, in the expectation that the information provided by the scientific community will be considered fully without political agendas determining the priorities.

     

基于模糊模式的蝗虫图像识别方法

蝗灾是中国农业病虫害防治的重点,采用低空机载蝗虫预警系统技术,对拍摄图像中蝗虫识别和计数,实现蝗虫监测,可以弥补蝗虫地面人工监测的不足。以广东省清远市英德区域农田为试验区,采用数码相机采集蝗虫图像,对蝗虫区域和背景的RGB分量平均值进行对比分析,选用超G绝对值法进行灰度转换,实现蝗虫与背景分离。通过面积统计对比,确定单个蝗虫的面积和周长特征,建立单个蝗虫模糊集和粘连重叠蝗虫区域模糊集,采用最大隶属度原则可以判定蝗虫连通区域为单个蝗虫或是存在图像粘连重叠。用模糊识别方法对单个和粘连重叠的区域分别计算数量,准     

智能化楼宇安防自动监控报警系统的研究

通过介绍智能化楼宇的类型和特点,阐述了智能化楼宇安防自动监控报警系统的组成结构,分析了智能化楼宇安防自动监控报警系统的工作原理及设计原则。通过实习案例论述了应用智能化楼宇安防自动监控报警系统后提高安防效率的重要性。     

The science and application of ecological monitoring

We provide a broad overview of the underlying philosophy of ecological monitoring. We argue that the major characteristics of effective monitoring programs typically include: (1) Good questions. (2) A conceptual model of an ecosystem or population. (3) Strong partnerships between scientists, policy-makers and managers. (4) Frequent use of data collected.We classify monitoring programs into three categories - (1) Passive monitoring, which is devoid of specified questions or underlying study design and has limited rationale other than curiosity. (2) Mandated monitoring where environmental data are gathered as a stipulated requirement of government legislation or a political directive. The focus is usually to identify trends. (3) Question-driven monitoring, which is guided by a conceptual model and by a rigorous design that will typically result in a priori predictions that can be tested.There are advantages and disadvantages of mandated monitoring programs, which are typically large-scaled, and generally smaller-scaled, question-driven monitoring programs. For example, while question-driven monitoring programs can provide insights into the ecological processes giving rise to emergent environmental patterns, spatial generalization from them is difficult because results may not extrapolate well to other regions, states or to a national level. Conversely, while mandated monitoring can be useful for producing coarse level summaries of temporal changes in a target population or resource condition they may not identify the mechanism influencing a change in an ecosystem or an entity. A key remaining challenge is to develop much improved mandated monitoring programs through more widespread adoption of the features of successful question-driven monitoring programs in efforts to enhance biodiversity conservation and environmental management.