Ecological corridors have recently garnered increasing international attention as promising biodiversity conservation models to study the effects of climate change. However, very few studies have characterized waterbird ecological corridors and their responses to environmental variations. Here, a hybrid model approach combining the least resistance model and circuit theory was applied to identify ecological corridors for four kinds of waterbirds (Grus japonensis, Grus grus, Cygnus cygnus, Mergus squamatus) in Northeast China. This region contains many wetlands that are rich in waterbird species and are important habitats and breeding grounds for waterbirds on the East Asia-Australia migration route. Our findings demonstrated that the least cost routes of different waterbird species and their pinch points (i.e., areas exhibiting high waterbird transit and density) have the potential to become waterbird ecological corridors. However, we observed substantial differences in the number of least-cost paths and the structure and distribution of ecological corridor networks due to differences in the number and distribution of waterbird core habitat patches. The number and distribution of pinch points were also different. Over 85% of the waterbird occurrence points were not far from the least-cost routes or the pinch points, indicating that the detected least-cost routes and the pinch points were not only ecological corridors for waterbirds but also priority areas for the conservation of waterbird habitat networks. The methods proposed herein could thus be used as a basis for the identification of multi-species waterbird ecological corridors in other countries, as well as forest bird ecological corridors at other scales.
本研究以“反向驯化”的理论视角对微信进行审视，提出微信发展带来的三大反向驯化特征，即自由交往带来的“自由陷阱”，社会比较滋生家居用户负面情绪，数字难民与数字仆人。并认为其“驯化”成因本质在于依靠技术逻辑支撑的技术力量不断发展，已忽视个体的价值理性，以此为个体对媒介的使用和媒介技术创造者以启发。
情景再现是纪录片制作中一种常用的手段,通常指通过演员重新演绎历史事件或真实故事的场景,让观众更加直观地了解事件的经过和情节.在使用情景再现时,编创者需要注意平衡真实性和戏剧效果,并尽量避免过度夸张和误导观众.
1 病例资料 患者男,52岁,因"维持腹膜透析1年余,发热2d余"到汕头大学医学院第一附属医院就诊.患者2019年于我院确诊为糖尿病肾病,予行腹膜透析置管术,术后规律非卧床腹膜透析治疗(1.5％葡萄糖透析液2 L×2袋+2.5％葡萄糖透析液2 L×2袋).
关于室内猛水蚤的培养,大部分采用微藻加饲料培养模式,但微藻培养成本高,加饲料投喂破坏水体环境.文章首次利用活体海生根鞭毛虫(Oxyrrhis marina)喂养环小两栖猛水蚤(Amphiascopsis cinctus),通过投喂海生根鞭毛虫,环小两栖猛水蚤可正常生长繁殖,且不同浓度的海生根鞭毛虫,对环小两栖猛水蚤发育时间、存活率以及繁殖的影响不同.在O.marina浓度分别为200ind·mL-1、800ind·mL-1、3200ind·mL-1、＞104ind·mL-1时,环小两栖猛水蚤发育时间随O.marina浓度的增加而减少,从无节幼体至桡足幼体阶段,发育时间从(16.30±0.82)d减少到(9.06±0.87)d;桡足幼体至成体阶段,发育时间从(15.94±0.63)d减少到(10.14±1.07)d;小两栖猛水蚤的存活率随着饵料浓度的增加而增加,无节幼体至桡足幼体阶段,存活率由36.72％提高到70.25％;桡足幼体至成体阶段,存活率由70.88％提高到85.62％,但最高存活率出现在次高浓度(3200 ind·mL-1)组中.在繁殖方面,环小两栖猛水蚤的挂卵量和孵化率随着O.marina浓度的提高而增加(7.86个·只-1-10.67个·只-1;50.83％-85.30％),孵化时间随着O.marina浓度的增加而减少(8.67d-5.12d).由此可见,高浓度的饵料可以缩短小两栖猛水蚤的发育时间,增加其繁殖效率,但当其发育至桡足幼体后,过高的饵料浓度反而降低了存活率,其原因还有待于进一步研究.
