22강 환경, 자원, 재활용
Gateway 소프트 패스 하천 공학
What ____ soft-path river engineering?
One way to visualize its spirit is to ____ it to a footpath in the forest.
Suppose a tree falls across a ____
A soft-path response would be simply to redirect the trail around ____ fallen tree.
A more interventionist response would be to remove the tree ____ restore the original route.
A still ____ interventionist response might be to straighten and pave the path to insert it more permanently in the landscape.
The true high-modernist step would, ____ course, be to create a superhighway that removes the landscape and bulldozes straight through all obstacles in the topography.
Soft-path engineering has the unique advantage of intellectual modesty with respect to what we actually know about river ____ and its environmental effects.
In contrast to hard-path engineering, soft-path engineering accepts variability in the river's movement ____ significant until proven otherwise.
Backwaters, short-lived wetlands, braids and channels, swamps ― all undesirable to hard-path ____ ― are presumed by soft-path engineers to be ecologically important.
Exercise 1 동식물종 이동을 위한 경관 연결성
Connectivity, the capacity of a landscape to ____ movement by any given species across the landscape, is of increasing concern for conservation biologists.
As the connectivity of a landscape ____ from the human 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 ____ or wandering through our backyards), landscapes substantially altered for human use act as barriers to movement of both animal and plant species.
In some ____ 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 exchange between previously connected plant and animal populations; dams can permanently halt spawning of fish by blocking travel to their ____ grounds.
Thus, lack ____ connectivity can decrease the conservation value of remaining habitat below what its mapped area might suggest, increasing the impact of fragmentation.
Exercise 2 바이오 발전
____ enhancing energy efficiency and putting waste products 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 ____ waste and liquid waste from pulp mill processing.
Biopower helps alleviate ____ change as well by reducing carbon dioxide 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 ____ 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
One example of human interventions ____ 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 strong effect on many aspects of the environment in which they ____
They diversify the ____ which they occupy and create a mosaic of habitats by browsing, trampling, and knocking over bushes and trees.
They also spread seeds through their eating and defecating habits and maintain or ____ water holes by wallowing.
____ these roles are beneficial to other species.
Conversely, where human interference prevents elephants from moving freely within their habitats and leads to their numbers exceeding ____ carrying capacity of the savanna, their effect can be environmentally disastrous.
Equally, if humans reduce elephant numbers in a particular piece of savanna, the savanna ____ become less diverse and less open, and its water holes may fill with mud.
____ will be harmful to other species.