应用遥感数据进行森林模式识别方法试验初探     

全志杰  王立宏 《西北林学院学报》1988,3(2):81-90

本文叙述应用Bayes判别进行遥感数据的森林模式识别原理和方法,并进行了小型试验,同时对三种不同处理数据方法的结果进行了比较。试验表明,应用电子计算机对遥感数据进行森林模式识别分类是可行的,方法灵活多样,而且精度可以保证。  相似文献   

基于贝叶斯方法的东、黄海鲐资源评估及管理策略风险分析   总被引：8，自引：1，他引：7  

李纲  陈新军  官文江 《水产学报》2010,34(5):740-750

运用基于贝叶斯的剩余产量模型,对东、黄海鲐资源进行评估,确定了当前鲐资源开发利用状态,估算了在不同收获率水平下未来5年鲐资源量和年总可捕捞量,分析了管理策略实施后鲐资源崩溃的风险。结果表明,2006年东、黄海鲐正遭受过度捕捞,但其资源量并未处于过度捕捞状态。决策分析表明,收获率为0.3是最适预防性的管理策略,在该策略下,鲐平均资源量将从2006年的451千吨将增加到2011年的871千吨,2011年资源量恢复到BMSY的概率为0.48,而过度捕捞的概率为0。  相似文献   

Dissolved oxygen controls summer habitat of Clear Lake Hitch (Lavinia exilicauda chi), an imperilled potamodromous cyprinid     

Frederick Feyrer  Matthew Young  Oliver Patton  David Ayers 《Ecology of Freshwater Fish》2020,29(2):188-196

Clear Lake Hitch is an imperilled minnow endemic to Clear Lake, Lake County, California, United States listed as threatened under the California Endangered Species Act (ESA) and a candidate for listing under the United States ESA. It exhibits a potamodromous life cycle whereby adults, which reach up to 6 + years in age and over 350 mm in length, migrate into Clear Lake's ephemeral tributaries briefly during spring to spawn. Conservation and management of Clear Lake Hitch is inhibited, in part, by a lack of information on the lacustrine habitat of nonbreeding individuals within Clear Lake. To address this problem, we sampled Clear Lake Hitch with gill nets in a stratified random sampling design to determine the distribution and habitat associations in early summer 2017 and 2018. We identified abundance-habitat relationships for juveniles and adults using Bayesian zero-inflated negative binomial generalised linear mixed modelling. Results indicated that dissolved oxygen concentration was the most important habitat feature measured; juveniles and adults were substantially more abundant in normoxic (≥2 mg/l) than in hypoxic (<2 mg/l) habitat. Both also exhibited weak positive relationships with chlorophyll fluorescence, suggesting relatively productive habitats may support higher numbers of Clear Lake Hitch. Spatially, juveniles were most abundant in nearshore habitats while adults were ubiquitous, indicating an ontogenetic habitat expansion that may be associated with a resource availability-predation risk trade-off. Management actions undertaken to improve hypoxia problems in Clear Lake would also improve Clear Lake Hitch habitat.  相似文献   

Development and testing of a Bayesian population model for the bigeye thresher shark,Alopias superciliosus,in an area subset of the western North Pacific     

Wen‐Pei Tsai  Yi‐Jay Chang  Kwang‐Ming Liu 《Fisheries Management and Ecology》2019,26(3):269-294

A Bayesian population modelling tool integrating separable virtual population analysis, per‐recruit models and age‐structured demographic analysis was developed for the bigeye thresher Alopias superciliosus (Lowe) population in an area subset of the western North Pacific. The mortality rates for years 1989–2016 were estimated, various biological reference points and associated risks of decline were also estimated, and alternative harvest strategies for the stock were evaluated. Estimates of the posterior mean of fishing mortality for bigeye thresher shark suggest fishing pressure has been high in recent years (2011–2016). The estimated population growth rate (λ) (without fishing) obtained from age‐structured demographic model was relatively low (λ = 1.01 per year; 95% confidence intervals of 1.00 and 1.03 per year). Risk analyses revealed that only low levels of fishing pressure (10% of the current fishing pressure) over a wide range of ages could maintain a relatively low risk of population decline for bigeye threshers. Sensitivity testing indicated that the model is robust to prior specification. The developed framework could be used as an assessment tool to evaluate the risk of decline for other widely distributed pelagic shark species where insufficient catch and effort data are available.  相似文献   

Balancing resource protection and fishing activity: The case of the European hake in the northern Iberian Peninsula     

Maria Grazia Pennino  Raul Vilela  Jose M. Bellido  Francisco Velasco 《Fisheries Oceanography》2019,28(1):54-65

One of the fundamental aims of the Ecosystem Approach to Fisheries Management is to ensure the long‐term sustainability of the fishery by protecting key life‐cycle habitats, such as recruitment areas. In this study, we apply a hurdle Bayesian hierarchical spatio‐temporal model that describes the abundance of European hake (Merluccius merluccius) recruits in the northern continental shelf of the Iberian Peninsula. Our findings clearly show four persistent nurseries, the main one being located along the continental shelf of the Artabrian gulf (off La Coruña). The preferential habitats identified for the hake recruits are areas within a bathymetric range of 120–200 m, with 15–16°C of Sea Surface Temperature, a Chl‐a concentration of 0.8–1.2 mg/m³ and low values of seabed rugosity (unconsolidated substrates). Searching for a compromise with fisheries, we also assess the degree of overlap of the main nursery areas with two fisheries footprints, a local one using Vessel Monitoring System data of trawl fishery of Marín, and a global one using Automatic Identification System data of different type of trawlers (bottom otter, beam and midwater trawls). The two fisheries footprints present different degree of overlapping in distinct areas, highlight the need of specific fleet‐adapted management rules in order to protect juvenile stages. We discuss that understanding the distributional patterns associated with key life stages, such as recruitment, and their interaction with fishing activities, is essential for applying appropriate spatial management measures and improving fishery sustainability.  相似文献   

Difficulties associated with modeling growth in the Atlantic angel shark (Squatina dumeril)     

Ivy Elizabeth Baremore  Kate Irene Andrews  Loraine Frances Hale 《Fisheries Research》2009,99(3):203-209

Several methods were used in an attempt to develop an age and growth model for the Atlantic angel shark (Squatina dumeril). Band counts from vertebral sections, which were fit to the traditional von Bertalanffy growth equation, the Gompertz growth equation, and the two-parameter von Bertalanffy growth equation, did not produce realistic parameter estimates. Additionally, a length-based Bayesian model was applied to fishery-independent length–frequency data, and a full Bayesian model was fitted to length-at-age data to estimate parameters for von Bertalanffy growth equation. Both the length-based and full Bayesian models failed to converge; the length–frequency data showed high bimodality unrelated to season, year, or other factors, and band counts were not predictable by length. Vertebral band counts were not valid for ageing Atlantic angel sharks, and length-based methods, which require normally distributed length–frequencies, were not appropriate for this data set. This study represents the first attempt at modeling age and growth for this species and provides research guidelines for future research initiatives.  相似文献   

基于贝叶斯分析的干热河谷区橙子林冠层蒸腾耗水模拟     

张晶莹  陈滇豫  马永胜  胡笑涛  杜敬斌  王书剑 《农业机械学报》2024,55(1):305-315

需耗水机制是进行农田/果园水分管理和调控的基础。本文聚焦蒸腾耗水机制,基于贝叶斯参数估计方法对比了不同Jarvis-Stewart模型配置对干热河谷区橙子林蒸腾耗水量的模拟效果,探索了Jarvis-Stewart模型在影响因子交互效应较强条件下蒸腾耗水模拟中的适用性。结果表明,考虑不同影响因子及其限制函数会对模拟效果产生较大影响,其中考虑土壤含水率和叶面积指数对模拟效果改善作用明显,而引入饱和水汽压差和气温则不同程度地降低模拟精度;考虑的影响因子越多,模型结构越复杂,模拟效果不一定越好;筛选出的最佳模型结构基本实现了橙子林蒸腾耗水的可靠模拟,但模拟效果仍有明显改进空间,因此,应综合考虑模型复杂程度、模拟精度及不确定性等,进一步探究适宜的模型结构。研究可为果园节水灌溉技术体系建立和水分管理优化提供科学依据,也能为耗水模型的进一步发展和完善提供理论支撑。  相似文献   

低场核磁共振结合化学模式识别方法判别休闲豆干品牌   总被引：1，自引：0，他引：1  

夏阿林  夏霞明  吉琳琳  赵良忠 《农业工程学报》2018,34(10):282-288

为了探求一种能快速准确地判别豆干品牌的方法,本研究采用低场核磁共振仪,对休闲豆干样品进行测量获取横向弛豫数据,结合主成分分析法(principal component analysis,PCA)、偏最小二乘判别分析(partial least squares-discriiminate analysis,PLS-DA)和贝叶斯正则化误差反向传播人工神经网络(bayesian regularization back-propagation artificial neural network,BR-BP-ANN)等化学模式识别方法对试验数据进行模式识别分析。选用4个常见的休闲豆干品牌,每个品牌分别收集5个批次的样品。每个批次随机选择16小包作为测试样品,共获得320个样品。使用低场核磁共振仪对这些样品进行测量,然后采用模式识别方法进行品牌判别。试验结果表明:对预测集豆干样品采用PCA进行判别分析时,从三维投影图中难以对各品牌进行人眼识别;运用PLS-DA方法对训练集样品的品牌识别率为86.3%,预测集样品的识别率为81.3%;然而使用BR-BP-ANN方法对预测集样品进行判别预测,预测值与实际期望值高度吻合,判别正确率均为100%,能够很好的实现对豆干品牌的判别。因此,采用BR-BP-ANN方法能够快速而准确地对豆干品牌进行识别,可为休闲豆干的品牌判别提供较好的技术支持。  相似文献   

Modelling individual variability in growth of bull trout in the Walla Walla River Basin using a hierarchical von Bertalanffy growth model          下载免费PDF全文

Julianne E. Harris  Courtney Newlon  Philip J. Howell  Ryan C. Koch  Steven L. Haeseker 《Ecology of Freshwater Fish》2018,27(1):103-115

We examined growth in length of fluvial bull trout (Salvelinus confluentus) in the Walla Walla River Basin, Washington and Oregon. Our objectives were to quantify individual variability in growth; examine growth within and among years, life history forms, life stages and sexes; and estimate von Bertalanffy growth parameters. Individual variability was evaluated by modelling asymptotic length (L_∞) and the growth coefficient (k) as random variables. All models were fit with Bayesian methods and were evaluated for fit by the deviance information criterion. By incorporating individual variability, population‐level estimates of L_∞ and k appeared appropriate and estimated growth trajectories for specific bull trout fit individual observed patterns in growth. Growth trajectories and positive correlation between individual estimates of L_∞ and k suggest that some individuals grow at a faster rate and reach a larger maximum size than other individuals and those differences are maintained throughout life. Selected models suggest that fluvial migrants have higher estimates of L_∞ and k than residents, but there were only slight differences in parameter estimates among migrants from two adjacent spawning populations in the Walla Walla River Basin, as well as between males and females. Growth rates increased for fluvial migrants after subadult emigration. Individual variability in growth is consistent with the life history diversity assumed essential for bull trout population persistence. Quantifying this variability is important for modelling population dynamics and viability to conserve this threatened species.  相似文献   

Ecophysiological characteristics of five weeds and a wheat crop in the Indo‐Gangetic Plains,India          下载免费PDF全文

Vartika Singh  Sweta Gupta  Hema Singh  Akhilesh Singh Raghubanshi 《Weed Biology and Management》2015,15(3):102-112

The objective of this research was to compare selected ecophysiological parameters for a wheat crop found in the Indo‐Gangetic Plains of India and its five dominant weeds. The dominant and regionally ubiquitous weeds in the wheat field that was selected for the study were Anagallis arvensis, Chenopodium album, Melilotus albus, Phalaris minor and Rumex dentatus. Taller weeds, such as C. album and P. minor, constituted one group along with the crop, with a low photosynthetic rate, specific leaf area, leaf nitrogen mass basis, chlorophyll content, photosynthetic nitrogen‐use efficiency and leaf area ratio, in comparison to shorter weeds, such as A. arvensis, M. albus and R. dentatus, which formed another group with a high photosynthetic rate, specific leaf area, leaf nitrogen mass basis, chlorophyll content, photosynthetic nitrogen‐use efficiency and leaf area ratio. Interspecific variations in the photosynthetic rate were driven mainly by variability in the specific leaf area and leaf nitrogen content. The taller weeds and the crop had a low specific leaf area later in the season, whereas the smaller weeds had a relatively high specific leaf area, which might be an adaptation to the shaded environment below the canopy. The result indicates that any weed management in the wheat fields of the Indo‐Gangetic Plains will need two different approaches because of the different strategies followed by the two weed groups that were identified in the present study.  相似文献