Subjects: Biology >> Ecology submitted time 2023-07-06
Abstract： Watershed biological information flow (WBIF) is defined as the path, processes and control of biological information transport, exchange, interaction and feedback among different spaces and systems along with watershed ecosystem processes, and could be partly described as the land-to-river and upstream-to-downstream bioinformation transportation (including organisms, nucleic acids, peptides and other biomarkers), which is driven by the hydrologic processes of watershed systems. The WBIF labels the transport of organic matter and energy. The WBIF integrates the ecological processes of environmental DNA (eDNA), including the origin, state, transport, and fate of eDNA, and makes it possible that the species composition in river system is monitored and assessed using eDNA. The WBIF estimation is the key for watershed ecosystem processes studying and riverine biodiversity monitoring. However, in practice, the parallel samples in each sampling site always are limited. And how parallel samples would impact WBIF estimation is unknown. Based on the principles of sampling survey, we hypothesized that parallel samples would not impact the accuracy of the WBIF estimation, but affect the precision of the WBIF estimation. Then, we transformed this hypothesis into a set of formulas and tested it with a series of analog computation. Results showed that the number of parallel samples (efficiency of detection) affected both the accuracy and precision of the WBIF estimation. The optimal WBIF estimation was less than the actual WBIF in any condition. Along with the increase of parallel samples (efficiency of detection), the optimal WBIF estimation gradually neared to the actual WBIF, the range of WBIF estimation gradually focused on the actual WBIF. In other words, more parallel samples (higher efficiency of detection) led higher accuracy and precision of the WBIF estimation. In addition, the actual WBIF affected both the accuracy and precision of the WBIF estimation too. Larger actual WBIF led higher accuracy and precision of the WBIF estimation. The relative relationship between the number of biological information types in upstream and downstream samples affected both the accuracy and precision of the WBIF estimation too. The accuracy and precision of WBIF estimation would be higher when the number of biological information types in upstream samples was more than those in downstream samples. So, we suggest that in the work of watershed ecosystem processes studying and riverine biodiversity monitoring, the relationship between parallel sample number and detection efficiency should be assessed, the suitable parallel sample number should be estimated based on the reliability target of WBIF estimation, the sampling program should be designed with suitable parallel samples, the WBIF should be estimated based on all parallel samples of each sampling site, at last the estimated results of WBIF should be re-evaluated according to the posterior probability of WBIF in different conditions. The current work provided the framework and methodology reference for the post-evaluation.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2020-11-20 Cooperative journals: 《干旱区地理》
Abstract：大数据时代，社交媒体的大量应用为研究游客情感体验以及探索其时空变化提供了新的数 据源。采集3 a间西安市国内游客微博签到数据，运用热点格网图法、Getis-Ord Gi*方法和X-means聚类方法，从积极情感和消极情感2个维度研究西安市国内游客情感体验时空变化和演化规律。结果表明：（1）城市中心、城市主轴线、主要商圈以及景区景点附近游客情感相对较高且稳定，高情感体验区域主要分布在曲江新区和西安古城旅游区。（2）消极情感体验在西安的交通枢纽和城市边缘的空间占比高，交通枢纽主要以车站、城市进出口为主。（3）整体上来看，3 a间西安市游客情感较为平稳，积极情感呈现“中心—边缘”的空间格局，消极情感和积极情感的呈现具有相似性，主要以3种类型为主：稳定型、相对稳定型和剧烈波动型。在3种类型中，稳定型的主要聚集地在城市中心、商圈附近、交通干线周边以及景区景点附近，相对稳定型占据西安市大面积区域，剧烈波动型处于距离城市中心较远的边缘。
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