Identify and discuss four ways in which forest trees are currently harvested. Which method is the most ecologically sound, and why? Which method is the most economical?© BrainMass Inc. brainmass.com October 9, 2019, 6:50 pm ad1c9bdddf
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Compare and contrast the designations of threatened, endangered, and extinct species. Describe three human causes of species endangerment and/or extinction.
Identify and discuss four ways in which forest trees are currently harvested. Which method is the most ecologically sound, and why? Which method is the most economical?
Following flow chart shows the different category recognized by ICUN :
Extinct means that the entire species has died out and can never return. Endangered animals are those in immediate danger of becoming extinct. Threatened species are likely to become endangered in the future.
S.No. Criteria Critically endangered Endangered Vulnerable
1 Reduction in population size over last 10 years or 3 generations > / = 80% > / = 70 % > / = 50 %
2 Geographic range in the form of
a Extent of occurrence 100 km2 5000 km2 20000 km2
b Area of occupancy 10 km2 500 km2 2000 km2
3 Population size estimated to number fewer than 250 mature ...
Human is the main culprit behind species extinction. Important anthropogenic reason for species extinction are habitat destruction, introduction of exotic species and overexploitation of species. Different parmeters were designed to categorised species into threatened, endangered and extinct species list. Accordingly ICUN has prepared a red data book.