However, severely impacted by intensive human activities, species resources in Yangtze River have been on constant decline, and the situation of migration species is among the worst.
由于人类活动的影响，长江大批物种资源持续衰退，而洄游性物种的衰退尤为严重。
Without more research, we can't predict if Assisted Migration will work for any given species.
没有更多的研究，我们无法预测辅助迁移是否适用于某一特定的物种。
Assisted migration means picking up members of a species, or members of a group of interdependent species and physically moving or translocating them.
辅助迁移指的是挑选一个物种的成员，或一组相互依赖的物种的成员，并在物理上移动或迁移它们。
In addition to all that, it is not even clear that assisted migration or any migration for that matter, will help at least for some species.
除此之外，我们甚至不清楚辅助迁移或任何相关的迁移是否至少对某些物种是有帮助的。
Currently there's no public policy on using assisted migration to help species survive climate change.
目前还没有公共政策在利用协助移徙来帮物种在气候变化中存活。
By looking at the fossil record from that period of time - before the Red Sea was formed - we can gain a clearer view of which species survived this great migration and which did not.
通过观察这一时期——红海形成之前——的化石记录，我们就能更清楚地知道哪些物种在这次大迁徙中活了下来，哪些没有。
As birders observe new species, they not only learn about different birds, but they also learn about migration, bird behavior, feed preferences, courtship and bird territories.
观鸟者观察各种新的物种，从中他们不止能认识不同的鸟种，还能学到关于迁徙、鸟类行为学、食性、求爱还有鸟类领地的知识。
Given their dependence on the single species, could they have made the migration without access to the whales?
考虑到图勒人对单一物种的依赖，他们能不让鲸鱼洄游吗？
They do not have a set migration pattern, unlike some other whale species - which raises questions about how they may adapt in future, if the projected declines in summer Arctic sea ice materialise.
它们没有一套迁徙的模式，不像其他的鲸类——假如夏季北极海冰像预计那样减少而成为现实的话，这就引起了关于它们如何适应未来的问题。
Life cycle, generation time, fecundity, and egg production quantity are the main factors to determine these two species' vertical migration.
生命周期、世代时间、繁殖力和产卵量是决定这两种桡足类垂直移动的主要因素。
One commission study concluded the dam would affect fish migration and could drive endangered species, like the Mekong giant catfish, to extinction.
委员会的一份研究断定，大坝将会影响鱼类的回游，并可能加速诸如湄公河巨型鲶鱼这类濒危物种的灭绝。
The latter process involves the expulsion of the neutral species (N, O-bidentate ligands), accompanied by hydrogen migration.
后者涉及氢转移的同时逐出中性分子碎片（N，O-双齿配体）。
The latter process involves the expulsion of the neutral species (N, O-bidentate ligands), accompanied by hydrogen migration.
后者涉及氢转移的同时逐出中性分子碎片（N，O-双齿配体）。
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