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371.
基于行为地理学“空间认知-空间偏好-空间行为”的经典研究范式,以中国科学院大学研究生为调查对象,采用手绘意象地图和问卷调查相结合的方式,在一年时间内分三轮开展跟踪调查,通过观察被访者在北京逗留期间的城市空间认知、偏好和行为过程与特征,分析空间认知-偏好-行为三者间的相互作用关系与影响机制。研究发现:城市空间认知、空间偏好与空间行为存在一定耦合性,亦表现出明显的差异性,三者间不是单向因果而是相互影响的互馈关系;除认知主体的社会、文化等群体属性、经验和情感等个体差异以外,与客体的接触时间、空间距离和接触频率等时空制约因素均能影响主体的城市空间认知水平与发展过程。最后,根据空间认知、偏好、行为的相互作用关系和影响制约因素,凝练出一般化的城市空间认知-偏好-行为互馈关联模型。 相似文献
372.
干旱灾害给整个自然灾害体系带来的经济损失最为严重,也是目前检测难度较高的自然灾害之一。SaTScan在灾害时空聚集区的识别中已有应用,但其存在参数设定困难、识别区域不够精确等问题。本文对Moran散点图和局部空间关联指标(Local Indicators of Spatial Association, LISA)进行时空扩展,提出了一种时空Moran散点图的方法,根据研究者对关注现象阈值及置信程度的要求,筛选出符合条件的点,并将其绘制在对应的时空坐标系上,从而得到时空聚集区。以2009—2014年中国干旱时空聚集区识别为例,结果表明:① 时空Moran散点图识别到的干旱时空聚集区与实际基本相符,验证了方法的有效性;同时,与时空扫描法相比,该方法具有识别结果边界清晰、精确,参数设置容易等优点;② 2009年和2011年呈现大范围、较强的干旱时空聚集区,2010年和2014年出现局部、较强的干旱时空聚集,而2012年和2013年的干旱时空聚集情况较轻。综合来看,2009—2014年干旱时空聚集区主要出现在云贵川、东北、黄淮地区和长江中下游等地区。 相似文献
373.
Seismic surveys are frequently a matter of concern regarding their potentially negative impacts on marine mammals. In the Southern Ocean, which provides a critical habitat for several endangered cetacean species, seismic research activities are undertaken at a circumpolar scale. In order to minimize impacts of these surveys, pre-cruise planning requires detailed, spatio-temporally resolved knowledge on the likelihood of encountering these species in the survey area. In this publication we present predictive habitat modelling as a potential tool to support decisions for survey planning. We associated opportunistic sightings (2005–2011) of humpback (Megaptera novaeangliae, N=93) and Antarctic minke whales (Balaenoptera bonaerensis, N=139) with a range of static and dynamic environmental variables. A maximum entropy algorithm (Maxent) was used to develop habitat models and to calculate daily basinwide/circumpolar prediction maps to evaluate how species-specific habitat conditions evolved throughout the spring and summer months. For both species, prediction maps revealed considerable changes in habitat suitability throughout the season. Suitable humpback whale habitat occurred predominantly in ice-free areas, expanding southwards with the retreating sea ice edge, whereas suitable Antarctic minke whale habitat was consistently predicted within sea ice covered areas. Daily, large-scale prediction maps provide a valuable tool to design layout and timing of seismic surveys as they allow the identification and consideration of potential spatio-temporal hotspots to minimize potential impacts of seismic surveys on Antarctic cetacean species. 相似文献
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DO Mirera 《African Journal of Marine Science》2017,39(3):315-325
The demand for mud crab Scylla serrata (Forsskål 1775) in the global market has increased, hence there is growing momentum to farm the species in Africa. Aquaculture production in Kenya and elsewhere in East Africa currently relies on juvenile seeds sourced from the wild. Wild-seed collection calls for management of the juvenile crab industry founded on knowledge of the species’ ecology, so as to achieve a sustainable seed supply and recruitment to the capture fishery. This study investigated the tidal, diurnal and seasonal occurrence of juvenile crabs in three habitats (intertidal-flat boundary zones, inside the mangroves, and in channels) in small creeks (Mida, Kilifi and Mtwapa) and Gazi Bay, on the coast of Kenya. Sampling was done with scoop nets and seining at receding tides and via burrow searches at low spring tides (day and night). Juveniles in the mangrove/intertidal-flat boundary zone were found sheltered under mangrove leaves or debris, or in shallow burrows during low spring tides, whereas at receding tides they could be seen moving out with the tide or searching for sheltering substrate or burrows. Catch per unit effort at high-abundance sites varied between 59 and 68 crabs fisher?1 day?1. More juvenile crabs, sized 10–80 mm internal carapace width (ICW), occurred at night during the receding tide. Net-seining was effective in the collection of juvenile mud crabs <30 mm ICW, whereas burrow sampling was effective for gathering larger crabs. However, collection of juveniles by seining reduced the quality of the crabs caught due to frequent loss of chelipeds, as compared with retrieving individual crabs by searching burrows. Some juveniles collected in the intertidal-flat boundary-zone habitat were either in the process of moulting or had just moulted, indicating the significance of this habitat for mud crabs at this physically delicate life stage. 相似文献
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