22강 환경, 자원, 재활용
Gateway 소프트 패스 하천 공학
What is soft-path ____ engineering?
One way to visualize its spirit is to ____ it to a footpath in the forest.
Suppose ____ tree falls across a footpath.
A soft-path response would be simply to redirect the trail ____ the fallen tree.
A more interventionist response would be ____ remove the tree and restore the original route.
A still more interventionist response might be to straighten and ____ the path to insert it more permanently in the landscape.
The true high-modernist step would, of course, be to create a superhighway that removes the landscape ____ bulldozes straight through all obstacles in the topography.
Soft-path engineering has the unique advantage of intellectual modesty with respect to what we actually ____ about river movement and its environmental effects.
In contrast to hard-path engineering, ____ engineering accepts variability in the river's movement as significant until proven otherwise.
Backwaters, short-lived wetlands, braids and channels, swamps ― all undesirable to hard-path engineering ― are presumed by soft-path engineers ____ be ecologically important.
Exercise 1 동식물종 이동을 위한 경관 연결성
Connectivity, the capacity of a landscape to support movement by any given species across ____ landscape, is of increasing concern for conservation biologists.
As the connectivity of a landscape increases from the human perspective (generally through increases in road networks), connectivity ____ for many other species.
Although we may ____ many species of animals moving across human landscapes (e.g. deer, wolves, and turtles crossing roads or wandering through our backyards), landscapes substantially altered for human use act as barriers to movement of both animal and plant species.
In some cases, these barriers are incomplete ― many turtles die on roads, ____ some make it across.
In other cases, passage is essentially impossible ― cities along landscape corridors such as river valleys can effectively eliminate genetic exchange between previously connected plant and animal populations; dams can ____ halt spawning of fish by blocking travel to their breeding grounds.
Thus, lack of connectivity can decrease the conservation value of remaining habitat below what ____ mapped area might suggest, increasing the impact of fragmentation.
Exercise 2 바이오 발전
By enhancing energy efficiency and putting waste ____ to use, biopower helps move utilities and industries in a sustainable direction.
The U.S. forest products industry now obtains half its energy by combusting woody ____ and liquid waste from pulp mill processing.
Biopower helps alleviate climate change as well by reducing carbon ____ emissions, and capturing landfill gas reduces emissions of methane, a potent greenhouse gas.
Biopower also benefits human health as it cuts down on pollution; by replacing coal in co-firing and direct combustion, biopower reduces emissions of sulfur dioxide because ____ matter, unlike coal, contains no appreciable sulfur content.
In addition, ____ resources tend to be geographically spread out, so using them can help support rural economies and reduce many nations' dependence on imported fuels.
Exercise 3 사바나의 특성을 바꾸는 인간 개입
One example of human interventions modifying the character ____ savannas is through their effects on savanna-dwelling mammals such as elephants.
They are what is known as a 'keystone species' because they have a strong effect on many ____ of the environment in which they live.
They diversify the ecosystems which they occupy and create a mosaic of habitats by browsing, trampling, and knocking over ____ and trees.
They also spread seeds through their eating and defecating habits and maintain or create water holes ____ wallowing.
All these ____ are beneficial to other species.
Conversely, where human interference prevents elephants from moving freely within their habitats and leads to their numbers exceeding the carrying capacity of ____ savanna, their effect can be environmentally disastrous.
Equally, if ____ reduce elephant numbers in a particular piece of savanna, the savanna may become less diverse and less open, and its water holes may fill with mud.
This will be harmful ____ other species.