Results 91 to 100 of about 16,842 (206)

气候变化对中国梅花鹿潜在栖息地影响

open access: yes野生动物学报, 2021
研究表明,气候变化将会使生物多样性降低甚至是物种灭绝。研究气候变化对物种栖息地的影响,对未来研究物种多样性和保护生态系统功能完整性提供实践意义。以梅花鹿(Cervus nippon)为研究对象,将23个环境因子通过去相关性后得到8个环境因子,利用最大熵(MaxEnt)模型模拟了梅花鹿基准气候条件下在中国潜在生境分布,并预测了ssp245和ssp585两种气候变化情景下2021—2040年(2030s)、2041—2060年(2050s)、2061—2080年(2070s)梅花鹿潜在分布。23个环境因子中,
刘策 张日 杜海荣 孙悦 袁子奥 于晶晶 张明海
doaj  

Chemical constituents from Wedelia prostrata and their cytotoxicity activity [PDF]

open access: yes, 2016
卤地菊(Wedeliaprostrata(Hook.etArn.)Hemsl.)为菊科蟛蜞菊属植物。对蟛蜞菊属植物研究调查表明,其主要含有二萜,倍半萜,黄酮和有机酸等化学成分。二萜尤其是对映-贝壳杉二萜类是蟛蜞菊属植物的主要活性成分,具有抗菌、抗病毒、抗氧化、抗癌、抗血管生成等生物活性。 本文首先用石油醚、乙酸乙酯、正丁醇三种不同极性的溶剂依次对卤地菊的乙醇提取物进行萃取,初步得到三个萃取部位,对卤地菊石油醚部位进行系统的化学成分研究,采用硅胶柱层析、聚酰胺柱层析、葡聚糖凝胶柱层析 ...
林剑虹
core  

Insights for conservation from the Ecological Knowledge Games project

open access: yesConservation Biology, EarlyView.
Abstract Environmental conservation research requires robust methods for collecting large‐scale behavioral data and engaging diverse stakeholders in decision‐making processes. We (Y.P., A.B.D., and N.B.) created EcoKnowGames (Ecological Knowledge Games), a transdisciplinary project that develops knowledge games for conservation science and data ...
Yuan Pan   +4 more
wiley   +1 more source

内蒙古达赉湖地区蒙原羚生境景观格局及动态研究

open access: yes野生动物学报, 2011
2009年7月、8月,2010年3月中旬、5月下旬,对内蒙古达赉湖地区蒙原羚进行野外考察并在生境适宜度分析的基础上,利用FRAGSTATS 3.3软件对达赉湖地区蒙原羚生境进行景观格局分析。通过比较1998年和2010年达赉湖地区蒙原羚生境适宜度评价结果,表明内蒙古达赉湖地区蒙原羚一般适宜生境、中度适宜生境和适宜生境的斑块不断被分割成更小的斑块,破碎化程度加大。蒙原羚不适宜生境斑块面积在增加,而一般适宜斑块、中度适宜生境和适宜斑块面积在减小,并且适宜生境面积变化程度最大 ...
刘丙万, 秦立鑫, 张博, 刘松涛
doaj  

Behavioral interventions to reduce demand for threatened freshwater turtles as pets

open access: yesConservation Biology, EarlyView.
Abstract Growing demand for freshwater turtles as pets has fueled illegal trade and accelerated wild population declines, underscoring the need for theory‐based demand‐reduction interventions. We conducted a three‐part randomized controlled trial with active turtle keepers (n = 1800) in China to test conservation‐ and legality‐framed messages by ...
Wuji Zheng   +9 more
wiley   +1 more source

The foraminiferal taxa in surface sediment and its environmental implication in Sansha Bay [PDF]

open access: yes, 2016
有孔虫对所生存的环境变化较敏感。对于不同的水深、温度、盐度、pH、沉积速率等环境因子的变化,有孔虫群落特征会发生相应变化。故有孔虫群落特征能较好地反映海洋环境变化。由于季节的变化,夏季和冬季所对应的环境因子条件不同,其有孔虫群落特征也会发生相应变化。本论文根据福建三沙湾的夏冬季24个站位表层沉积物样品,进行有孔虫鉴定和沉积物粒度分析。在广泛收集前人资料及室内分析的基础上,结合表层沉积物中七种重金属含量平面分布特征,通过研究分析有孔虫种群的空间分布及其与环境因子间相互关系 ...
龚凌
core  

Transitioning From L1 Medium of Instruction to L2 English Medium Instruction: The Role of Translanguaging in Contributing to EFL Students’ Language Learning Motivation

open access: yesInternational Journal of Applied Linguistics, EarlyView.
ABSTRACT Research on English‐Medium‐Instruction (EMI) highlights inadequate support for students transitioning from L1‐medium‐instruction to EMI. To date, little research has focused on how L2 students’ adaptation to an EMI environment influences their L2 learning motivation (LLM).
Kevin W. H. Tai
wiley   +1 more source

松花江流域哈尔滨段三生空间演变的生态环境效应及驱动因素分析

open access: yesShuitu Baochi Xuebao, 2022
探索三生空间演变的生态环境效应及驱动因素, 可为国土空间优化及生态环境保护的实施提供科学依据。以松花江流域哈尔滨段为例, 运用网格单元法, 结合生态环境质量指数、全局自相关模型、核密度函数等方法分析1986—2016年三生空间演变的生态环境效应时空分异特征, 并借助地理探测器模型揭示生态环境质量空间分异的驱动因素。结果表明: (1)1986—2016年研究区三生空间以生产空间为主, 其中农业生产空间和林业生态空间所占比重最大, 呈现生产空间和生态空间减少、生活空间增加的变化趋势; (2 ...
盖兆雪   +3 more
doaj  

Mass mortality of mangroves in Qingmeigang Bay, Sanya—an indication of mangrove fate resulted from accelerated sea-level rise in the future [PDF]

open access: yes, 2015
在全球变化的各种效应中,海平面的上升是对红树林最大的威胁之一。发生在海南三亚青梅港红树林自然保护区的红树林突发大面积死亡事件作为海岸工程引起红树林淹水时间与深度增加并导致红树林大规模死亡的特例为研究海平面上升对红树林影响提供一个新的角度。未来不断上升的海平面对红树林的破坏作用在此次事件中被间接反映出来。对青梅港红树林死亡事件的调查研究不仅为青梅港地区红树林的恢复、管理提供理论依据,而且对于探讨海平面上升对红树林的影响存在重要意义 ...
傅海峰
core  

A Systematic Review on Generative AI in L2 Speaking Development From a Self‐Determination Theory Perspective

open access: yesInternational Journal of Applied Linguistics, EarlyView.
ABSTRACT Second or foreign language (L2) speaking is a key aspect of L2 competence. While GenAI shows potential to address challenges in L2 speaking development, its role remains insufficiently understood. Self‐Determination Theory (SDT) could explain student language learning engagement. Therefore, this systematic review examines how GenAI affordances
Yanyan Catherine Lin   +3 more
wiley   +1 more source

Home - About - Disclaimer - Privacy