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