Environmental drivers of tadpole community structure in temporary and permanent ponds     

《Limnologica》2020

About 87 % of the anuran species that occur in Brazil possess a larval stage, i.e., tadpoles. Throughout this stage of development, tadpoles are subject to predation and the conditions of their aquatic habitat, including environmental heterogeneity, physical and chemical properties of the water, and hydroperiod of the water body. We assessed the patterns of species composition and richness of tadpoles in permanent and temporary ponds, with the objective of evaluating how morphometric, physical and chemical factors of the ponds and environmental heterogeneity (surrounding vegetation and substrate cover and aquatic vegetation) affect anuran occupation of these environments. The study was performed in five permanent and four temporary ponds. Tadpoles of 20 anuran species differed in species composition between permanent and temporary environments. Environmental factors were significant drivers for tadpole richness: turbidity and dissolved oxygen were significantly related to richness in permanent ponds, while water temperature and pH were significantly correlated to richness in temporary environments. Higher species richness was related to the heterogeneity of the ponds and greater complexity associated with the stratification of the surrounding vegetation. In general, the results suggest that species sorting of tadpoles is probably related to the high environmental variation among permanent and temporary aquatic habitats. The spatial heterogeneity of these two types of environments increases local diversity by accommodating species that are unique to only one habitat type.  相似文献   

Stone cover and slope factors influencing hillside surface runoff and infiltration: laboratory investigation     

Jiin‐Shuh Jean  Koe‐Fe Ai  Kaimin Shih  Chao‐Chi Hung 《水文研究》2000,14(10):1829-1849

In this study, laboratory rainfall simulation in an extensive area was used to study the infiltration, and interception and storage from surface runoff in points with different stone cover percentages (0, 10, 20 and 30%) and slopes (5°, 10° and 20°). The experimental results of this study showed that the interrelationships among the slope, stone cover percentage, groundwater level, surface runoff amount, and interception and storage of the ponds were varied and irregular. No systematic patterns were detected for the change in the groundwater level, surface runoff amount, and interception and storage of the ponds with different stone cover percentages at different slopes and no threshold values were apparent. For a 5° slope, if the stone cover percentage was increased, the amount of surface runoff was reduced, the infiltration and the groundwater level experienced no significant change, and the interception and storage of the ponds increased. For a 10° slope, if the stone cover percentage was increased, the amount of surface runoff increased, the infiltration decreased, the groundwater level experienced no significant change or decreased slightly at certain points, and the interception and storage of the ponds increased. For a 20° slope, if the stone cover percentage was increased, the amount of runoff increased, the infiltration decreased, the groundwater level experienced no significant change or decreased slightly at certain points, and the interception and storage of the ponds increased. With or without stone cover, when the hydraulic conductivity of the top material is close to that of fine sand or laterite, an increase in the slope gradient decreased the amount of surface runoff and increased the storage amount of the ponds. As for the stone distribution, an interlaced style showed better performance in the interception and storage of ponds than that of a regular style. There was no significant change in the groundwater level. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

基于无人机高光谱遥感技术对内陆养殖池塘水质监测的研究     

刘梅  马启良  原居林  倪蒙  练青平  郭爱环 《海洋与湖沼》2022,53(1):195-205

为准确、快速、全面获取内陆养殖小区池塘及尾水处理池水体水质变化情况,建立养殖水环境实时预警调控及数字化管控机制,选择浙江湖州市集中连片的养殖小区为试验区,于2020年12月采用搭载GaiaSky-mini高光谱相机的无人机进行试验区近地遥感图像采集,并进行图像拼接、辐射校正和几何校正等预处理;然后对反射波段进行差值、比...  相似文献   

熔体包裹体在估算花岗岩类矿床形成压力(深度)方面的应用   总被引：3，自引：1，他引：2  

李建康  张德会  李胜虎 《矿床地质》2011,30(6):1002-1016

在花岗岩类矿床中,花岗岩浆分异出富挥发分熔体/流体的过程,是导致岩浆就位和成矿元素迁移、富集的关键因素之一.在该过程中,同时捕获的不同类别的熔体包裹体和流体包裹体可以互相限定捕获条件,由此可以建立一系列与熔体包裹体有关的地质压力计,进而得到相关分异作用发生的深度.这些深度数值,对于指导花岗岩地区的找矿工作具有重要价值....  相似文献   

益生菌对海水虾池浮游生物的生态调控效果研究   总被引：1，自引：0，他引：1       下载免费PDF全文

张汉华  李卓佳  郭志勋  曹煜成  贾晓平 《海洋科学》2009,33(1):12-20

研究了益生菌对海水虾池浮游生物的生态调控效果.通过对对虾养殖系统中浮游动物与浮游植物进行为期3个月的监测,结果表明试验池的浮游植物数量表现为前期低,种类以硅藻类为主,中期迅速增长,后期达顶峰,并维持在70×106～160×106个/L的水平,种类则以绿藻类为主;不施加益生菌制剂的对照池则在后期出现较大比例的有害的蓝藻类,而试验池的蓝藻类只占较少的数量,说明益生菌群能抑制蓝藻类的繁殖,促进有益藻类生长;同时试验虾池浮游动物的数量也保持稳定增长态势,并在养殖后期维持在顶峰水平,密度达到25×103-30×103个/m3,种类以广盐、适低盐的沿岸种为主,优势种明显,而对照池的浮游动物数量较低且起伏较大.浮游动物与浮游植物的数量变动趋势基本一致,两者之间呈现较为密切的线性关系,两者之间的线性系数平均为0.724;多样性指数在1.1～1.6之间,低于自然海区;种类均匀度则较高,与自然海区相当,在0.5～0.7之间,试验池比对照池的养殖效果好.  相似文献