Results 31 to 40 of about 384,804 (159)
粉红胸鹨(Anthus roseatus)是卧龙自然保护区的夏候鸟,高山草甸的优势种类。笔者自1979年以来,在春季对比鸟的垂直迁移进行了一些观察。1988年春季,又进行专题观察,现报告如下: 观察区概况卧龙自然保护区位于四川盆地向青藏高原过渡的高山峡谷地带;东南低,西北高;最低海拔1 200米,最高海拔6 250米。海拔1 600米以下为山地亚热带常绿阔叶林带;海拔1 600—2 000米为山地暖温带常绿,落叶阔叶林带;海拔2 000—2 600米为山地温带针阔叶混交林带;海拔2 600—3 ...
李洪成
doaj
This research reveals the functional stability of mixed species foraging flocks (MSF) and their foraging height change with different taxonomic differences along the elevational gradient at Knuckles Montane Reserve, Sri Lanka. This offers new insights into how MSFs sustain with the elevational gradients supporting the altitudinal shifting species ...
Vimukthi. R. Gunasekeara +3 more
wiley +1 more source
高海拔下比平原地区气体密度小,放电电压降低。因此,高海拔应增加线路的绝缘强度。在绝缘子串中多采用几片绝缘子来改善绝缘子串电压分布。本文依据架空线路设计规程计算了高低海拔500 kV线路采用U210B瓷质绝缘子应当选取的片数,并依此搭建了高低海拔绝缘子串的等效电路,计算并比较了其电压分布。在高低海拔的等效电路中,通过改变劣化绝缘子的位置和数目,计算劣化绝缘子的电压降,对比分析研究劣化绝缘子对不同海拔电压分布的影响。结果表明:相同情况下,高海拔劣化绝缘子的电压降百分比更大 ...
罗浩 +7 more
doaj
利用舟山浮标站和海岛自动站2011年全年测风数据资料,对舟山海域浮标风力和附近非遮蔽高海拔海岛站以及不同海域无遮蔽海岛站、遮蔽海岛站的风力进行了对比分析,结果表明:1)浮标站大风日数比非遮蔽海拔较高海岛站以及传统大风指标站嵊泗明显偏少,比遮蔽海区海岛站多.2)浮标站年平均风速小于非遮蔽高海拔站,同嵊泗、西磨盘接近,大于遮蔽海区海岛站.3)浮标站大风日数和平均风速具有明显的月际变化特征,秋冬季明显多于春夏季.4)对比不同风向的大风过程可得:浮标站与其他海岛站的风速差值不仅与季节变化、海拔高度有关 ...
LIYun(李云) +3 more
doaj +1 more source
Pometia pinnata demonstrated life‐stage‐specific genetic responses to landscape features, with asymmetric gene flow patterns and population recovery following historical bottlenecks, revealing complex topographic and demographic influences on forest genetic structure.
Madhuparna Chatterjee +5 more
wiley +1 more source
We collated detections of the sun bear from new and previously published camera trap studies across its range. We then analysed these detections at two different spatial scales to assess the habitat associations and diel activity of this species. We found that the sun bear is tolerant to moderate habitat disturbances. ABSTRACT Degraded tropical forests,
Alexander Hendry +5 more
wiley +1 more source
对冀北山地阳坡不同海拔蒙古栎天然林分枯落物层及土壤层进行了初步研究,结果表明:(1)样地二(海拔1 180 m)的枯落物总蓄积量最大为33.18 t/hm2,其次为样地三(海拔1 260 m),最小为样地一(海拔1 100 m),为14.20 t/hm2,即随海拔升高枯落物总蓄积量先增大后减小。最大持水率的变动范围为140.83%~229.81%,随海拔升高而降低。样地二的有效拦蓄力最强,为39.22 t/hm2,样地三拦蓄能力最弱,为20.58 t/hm2,即中海拔拦蓄能力最强,高海拔最弱。(2 ...
田超 +5 more
doaj
基于高海拔地区山地和平原两类地貌1.5年的实测脉动风风速数据,确定了两类地貌风剖面指数、湍流强度的均值和98%保证概率值,分析了高海拔风场特性参数对输电线路风压高度变化系数、杆塔风振系数和导地线风振系数的影响规律,高海拔地区风剖面指数不应高于A类场地风剖面指数0.12。确定了高海拔与标准B类地貌下杆塔和导地线风荷载的差异,通过结构受力分析得到了高海拔地区杆塔应力及分布特征,两类地貌风场下杆塔最大应力比较B类地貌均有所增加,且山地地貌风场更为不利,杆件最大应力比达到了1.14 ...
杨风利 +4 more
doaj
This study investigates distribution patterns of Galliforms in the Indian Himalayas, focusing on factors influencing their occurrence, regions of high diversity and endemism, and their overlap with protected areas. Our study highlights the need for assemblage‐level conservation strategies in high Himalaya which primarily relies on snow leopard‐focused ...
Manvi Sharma +5 more
wiley +1 more source
小熊猫在高黎贡山不断受到人为干扰,生存环境日益缩小.调查表明,东坡小熊猫主要在海拔28003100m活动,西坡小熊猫主要在海拔28003500m活动,冬季生境密集利用带为海拔28003000m,春季以后为海拔33003500m,并主要在山脊活动.这些现象均与躲避人类有关.
张家胜, 施晓春
doaj

