Results 111 to 120 of about 15,934 (187)

两栖动物的受危及保护

open access: yes野生动物学报, 1999
种群的灭绝两栖动物是脊椎动物的一大类群,从世界范围来看正在不断灭绝,而且种群的灭绝率随时间在加大.如丹麦博恩岛上的无斑雨蛙(Hyla arborea),其灭绝率19501960年为36%,19601970年为45%,19801990年为60%.19771986年在丹麦调查的1300个地点与40年代和60年代的资料相比较,发现50%的种群消失了,其余种群也极大地减小了.珍稀种比普通种减少更快.对两栖动物种群的监测需要长期进行,否则有可能得出错误结论 ...
江建平, 周开亚
doaj  

Can Online Participation Match In‐Person Democratic Engagement? Evidence From a Cross‐National Experiment

open access: yesPolicy &Internet, Volume 18, Issue 3, September 2026.
ABSTRACT Democratic innovations increasingly take place online, yet little is known about how online citizen participation affects perceived legitimacy compared to in‐person formats. This study presents findings from a preregistered vignette experiment conducted in Spain and Switzerland.
Valeria Vuk
wiley   +1 more source

Interconnections of Water and Menstrual Justice: Understanding Water Justice as a Menstrual Justice Issue in Canada

open access: yesSexuality, Gender &Policy, Volume 9, Issue 3, August 2026.
ABSTRACT Menstrual justice is deeply interconnected with water justice, yet these topics remain largely siloed in policy and research—particularly in Canada, where water access is often assumed to be a non‐issue. However, existing literature reveals that inadequate water and infrastructure significantly affect menstrual hygiene, dignity, and health ...
Emma Cowman   +4 more
wiley   +1 more source

极端天气气候事件对宁夏野生动物种群安全的影响

open access: yes野生动物学报, 2009
通过问卷调查和样地调查方法,分析极端天气气候对宁夏野生动物种群安全产生的影响。极端天气气候对优势物种数量影响严重。雀形目种群安全主要受到沙尘暴、冰雹和暴雨的影响较大;迁徙鸟类种群安全主要受到沙尘暴、冰雹和暴雨的影响较大;啮齿类种群安全主要受到暴雨的影响较大;岩羊种群安全受到沙尘暴、冰雹、暴雨和降雪的影响。
刘晓红
doaj  

Root economic space is associated with rhizosphere microbial divergence via root metabolite‐mediated pathways in degraded grasslands

open access: yesFunctional Ecology, Volume 40, Issue 7, Page 2068-2082, July 2026.
Read the free Plain Language Summary for this article on the Journal blog. Abstract Grasslands worldwide are experiencing severe degradation due to overgrazing, climate change and anthropogenic disturbances, resulting in substantial declines in biodiversity and ecosystem functioning.
Xiaoqi Wang   +5 more
wiley   +1 more source

鸭儿湖摇蚊复组种群酯酶多态性的研究 [PDF]

open access: yes, 2002
应用淀粉凝胶电泳研究了从湖北鸭儿湖污染区采集的较耐污染的摇蚊复合组幼虫 ,结果发现 :在取样种群中存在高活性的 β酯酶 (EST) ,其电泳迁移率与致倦库蚊实验参考系均不同 ;从甘油醛 - 3 -磷酸脱氢酶 (GPD)染色结果发现 ,其酶谱与已报道的库蚊 GPD染色结果有很大不同 ,在污染最重的 1号氧化塘的摇蚊复合组幼虫的 GPD没有表达 ;但在中度污染的2、3号氧化塘中 ,摇蚊复合组幼虫 GPD位点呈现明显多态现象。群体遗传学分析结果表明 ,取样种群由于杂合子不足造成种群偏离哈迪 ...
李瑄,乔传令,徐盈
core  

白头鹤国内圈养种群现状分析

open access: yes野生动物学报, 2015
对中国白头鹤圈养种群的统计学和遗传学结果进行了相关分析,并对种群数量、年龄结构、性比情况、基因多样性、近交系数以及未来100 a种群的发展趋势进行了重点研究。结果表明:截止到2013年12月31日,中国圈养白头鹤种群共有存活个体76只,分别饲养于15家单位,其中建立者的数量为16只,潜在建立者的数量为41只。圈养白头鹤种群中育龄个体充足,但幼龄个体数量不足,种群年龄结构不是很合理。白头鹤种群保留了野生个体92.9%的基因多样性,平均近亲系数为0,是一个没有任何近亲繁殖的优质种群。通过分析发现 ...
何相宝 田秀华 李晓敏 周军英 尹惠媛
doaj  

Flexible parental care in a songbird correlates with sex‐specific responses to seasonal phenology, mating opportunity and reproductive success

open access: yesJournal of Animal Ecology, Volume 95, Issue 7, Page 1178-1193, July 2026.
This population‐comparative study reveals that male and female parents respond differently to social and ecological conditions. This sex‐specific responsive strategy is related to the incongruent parental care systems across populations in Chinese penduline tits.
Jia Zheng   +5 more
wiley   +1 more source

新疆肖塘地区胡杨的种群结构与动态[J] [PDF]

open access: yes, 2013
采用样线法在新疆塔里木河中游的肖塘地区设置4块100 m×100 m的样地,对样地内的胡杨种群进行每木调查并获得野外资料.采用空间代替时间的方法对胡杨的种群结构进行分析.结果表明:胡杨种群的径级结构分布整体上呈现两头低中间高的特点;随着样地与河道的距离变大,样地的胡杨密度整体上呈下降趋势,大龄级个体所占比例呈增加趋势,Ⅲ龄级以下个体所占比例减小;随着龄级的增加,种群致死率出现的2个高峰在Ⅳ~Ⅴ龄级间和Ⅷ龄级以上.此外,对种群动态指数与时间序列的分析表明:Ⅰ、Ⅱ龄级的动态值为负,由于没有低龄个体的更新 ...
陆亦农   +6 more
core  

基于种群生存力分析的陕西铜川朱鹮再引入种群的可持续性及保护对策

open access: yes野生动物学报
种群生存力分析(population viability analysis,PVA)虽然已经在濒危物种的保护管理中得到广泛应用,但目前面临的严峻挑战是如何采用PVA分析影响濒危物种种群长期维持的内外因子。经过数十年的保护,朱鹮(Nipponia nippon)野生种群的数量已经从7只增长到约4 400只,若干再引入计划也分别在中国、日本和韩国相继实施。过去的研究表明,种群统计随机性、灾害和种群性比等因素是影响朱鹮野生种群稳定增长的主要因素,然而,对影响朱鹮再引入种群长期稳定维持的因素却知之甚少 ...
王华强   +3 more
doaj  

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