Results 1 to 10 of about 998 (103)
Identifying socioeconomic and biophysical factors driving forest loss in protected areas
Abstract Protected areas (PAs) are a commonly used strategy to confront forest conversion and biodiversity loss. Although determining drivers of forest loss is central to conservation success, understanding of them is limited by conventional modeling assumptions.
Kathryn A. Powlen +3 more
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Abstract Stand structure develops with stand age. Old‐growth forests with well‐developed stand structure support many species. However, development rates of stand structure likely vary with climate and topography. We modeled structural development of 4 key stand variables and a composite old‐growth index as functions of climatic and topographic ...
Yuichi Yamaura +6 more
wiley +1 more source
为研究不同坡长客土坡面产流产沙及沟蚀特征差异变化,通过设计2个坡度(15°,20°)下不同坡长(2,4,6,8,10 m)的野外径流小区进行冲刷试验。结果表明:(1)初始产流时间变化范围与产流停止时间均随坡长增加而增大,产流率初期快速增加,达到初次峰值后呈现不规律波动,累积产流量随坡长增加而增多;产流率、累积产流量与坡长、产流时间及其交互作用呈极显著相关(p<0.01),累积产流量在2种坡度下均与坡长、产流时间呈幂函数相关。(2)产沙率初期快速增加,达到初次峰值后随冲刷时间逐渐下降 ...
张馨予 +6 more
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为揭示自然降雨下翻耕除草和坡长对紫色土氮、磷流失的影响,通过野外设置径流小区(2个坡面:翻耕除草与自然恢复;3种坡长:20,40,60 m,共9个小区),定位监测研究不同处理下产流产沙及氮、磷流失特征。结果表明,同一坡面不同坡长间产流产沙差异不显著(P>0.05);同一坡长不同坡面处理小区的径流量、产沙量差异极显著(P0.05),其他坡长DN、DP流失量差异显著 ...
梁珂 +4 more
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为探究坡形对浅沟发育的影响,以陕西省靖边县狼儿子沟无人机航摄影像为基础数据,通过目视解译得到浅沟(指瓦背状地形底部)225条,统计了浅沟条数、浅沟长度、沟头到分水岭的距离及浅沟密度等指标。利用浅沟地形分水线上的高程点进行插值得到原始坡面数字高程模型(digital elevation model,DEM),以此DEM提取地形曲率以表征坡形,进而分析坡形与浅沟指标的关系。结果表明:(1)以浅沟地形分水线上的高程点插值后的DEM对浅沟进行了综合,能较好地表达浅沟发育之前原始坡面的地形特征。(2 ...
王海于 +4 more
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Indian Pangolin in Lamjung Requires Urgent Attention 尼泊尔拉姆琼县地区的印度穿山甲急需关注
This study documented the first evidence of the Indian pangolin in Lamjung district, Nepal, finding three burrows and rescue evidence in Simalchaur Naringhat Community Forest. The burrows identified at an elevation of 530 m and characterized by moderate crown and ground cover (26%–50%), a 25° slope, and predominantly red soil, are indicative of a ...
Asmit Neupane +4 more
wiley +1 more source
Abstract Eradicating invasive predators from islands can result in substantial recovery of seabirds, but the mechanisms that drive population changes remain poorly understood. Meta‐analyses have recently revealed that immigration is surprisingly important to the recovery of philopatric seabirds, but it is not known whether dispersal and philopatry ...
Jeremy P. Bird +2 more
wiley +1 more source
Aid relations in protracted displacement comprise a diversity of actors with different influence and involvement over time. Building on the case of Sri Lanka's northern Muslim's expulsion from the north of the country in 1990, this paper investigates the dynamic space of aid relations in their drawn‐out internal displacement.
Cathrine Brun +4 more
wiley +1 more source
通过野外水流冲刷试验,对比分析了不同坡长条件下坡面产流产沙及氮磷流失特征。结果表明,上方来水流量一定时,坡长越长,其坡面入渗量越大,径流量越小,且存在一个临界坡长,使得径流量和入渗量相当,累计径流量与坡长是负线性关系。随着坡长增加,产沙量增大,单位坡长的泥沙流失量在各坡长条件下差异并不显著(P>0.05)。累计泥沙量随着坡长增大而增大;幂函数比指数函数能更好的描述硝态氮和水溶性磷浓度变化过程;泥沙中硝态氮和有效磷的含量整体上随时间呈减小趋势。坡长越长,其养分富集率越大;随着坡长增大 ...
赵光旭, 张鹏宇
doaj
基于WEPP模型的工程建设中施工便道边坡水土流失特征——以林芝市巴宜区为例
工程建设中施工便道导致的水土流失与传统土壤侵蚀不同,施工便道改变原自然坡面形态及水文过程,致使植被破坏、地表裸露,并形成路面、挖填边坡等多个侵蚀产沙部位,结构松散的路堑及边坡对降雨的响应更强、速度更快,土质低等级道路所引起的土壤侵蚀问题占比很大,因此研究可为工程扰动中施工便道的水土流失防治提供基础依据。以林芝市巴宜区为研究对象,采用WEPP模型对工程扰动下不同降雨条件、不同坡度坡长情况下施工便道边坡径流量、土壤流失量进行模拟分析,揭示施工便道边坡水土流失特征规律和关键影响因素。结果表明:(1 ...
于洋 +6 more
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