With reference to 'desertification', as described in the passage, the following assumptions have been made : 1. Desertification is a phenomenon in tropical areas only. 2. Deforestation invariably leads to floods and desertification. Which of the above assumptions is/are valid?

Passage

Desertification' is a term used to explain a process of decline in the biological productivity of an ecosystem, leading to total loss of productivity. While this phenomenon is often linked to the arid, semi-arid and sub-humid ecosystems, even in the humid tropics, the impact could be most dramatic. Impoverishment of human-impacted terrestrial ecosystems may exhibit itself in a variety of ways : accelerated erosion as in the mountain regions of the country, salinization of land as in tht semi-arid and arid 'green revolution' areas of the country, e.g., Haryana and western Uttar Pradesh, and site quality decline—a common phenomenon due to general decline in tree cover and monotonous monoculture of rice/wheat across the Indian plains. A major consequence of deforestation is that it relates to adverse alterations in the hydrology and related soil and nutrient losses. The consequences of deforestation invariably arise out of site degradation through erosive losses. Tropical Asia, Africa and South America have the highest levels of erosion. The already high rates for the tropics are increasing at an alarming rate (e.g., through the major river systems—Ganga and Brahmaputra, in the Indian context), due to deforestation and ill-suited land management practices subsequent to forest clearing. In the mountain context, the declining moisture retention of the mountain soils, drying up of the underground springs and smaller rivers in the Himalayan region could be attributed to drastic changes in the forest cover. An indirect consequence is drastic alteration in the upland-lowland interaction, mediated through water. The current concern the tea planter of Assam has is about the damage to tea plantations due to frequent inundation along the flood-plains of Brahmaputra, and the damage to tea plantation and the consequent loss in tea productivity is due to rising level of the river bottom because of siltation and the changing course of the river system. The ultimate consequences of site desertification are soil degradation, alteration in available water and its quality, and the consequent decline in food, fodder and fuel-wood yields essential for the economic well-being of rural communities.

Question

CSATMediumPrelims 2018Comprehension

With reference to 'desertification', as described in the passage, the following assumptions have been made :

Desertification is a phenomenon in tropical areas only.
Deforestation invariably leads to floods and desertification.

Which of the above assumptions is/are valid?

Explanation

Assumption 1 is incorrect: The passage explains that desertification is not limited to arid regions, but can also affect semi-arid, sub-humid, and even humid regions, such as the humid tropics. Therefore, stating that desertification is limited to arid regions is an incorrect assumption.

Assumption 2 is correct: The passage mentions that deforestation leads to several adverse consequences such as soil degradation, altered hydrology, and increased erosion, all of which can contribute to phenomena like flash floods and desertification. Therefore, the assumption that multiple adverse effects of deforestation can combine to lead to desertification is valid.