Efectos y consecuencias del estrés académico sobre el rendimiento

Population pressure has been identified as the major force for environmental change in the twentieth century.1 _{Yet, while macrolevel analysis of the inter-}

action between human populations and the environment demonstrates that population dynamics relate to environmental change, the correlation does not always originate from a direct causal relationship. Moreover, the relationship between population pressure and environmental change and the outcomes of change is not necessarily linear. Rather the impact of population density on a forest environment is ambiguous and multifaceted. Where and how people im- pacted on local environmental resources was as important as how many people affected the environment of north-central Namibia.

Malthus argued that population increased at a far greater rate than food production, and neo-Malthusian analysis identifies population growth as the principal cause of deforestation in Africa, Asia and Latin America. Boserup and others, on the other hand, stress that population growth can have the opposite effect because intensification and technological innovation can permit the same resource base to support a larger population without environmental degrada- tion.2 _{Both approaches portray ‘population’ and ‘forest’ as undifferentiated and}

1 _{Myers, Deforestation Rates, pp. 20-23, 45-47; Williams, Deforesting the Earth, pp.}

168-209, 334-379, 460-466.

2 _{Malthus, An Essay on the Principle of Population. See also Ehrlich, The Population}

organic entities. Moreover, the relationship between the two variables is de- picted as being a mechanical, linear, one-way and unequal interaction, i.e. human populations are dominant and act upon the forest.3 _{The population}

pressure model to some extent approximates cultural determinism, as opposed to environmental determinism. The underlying causes of population growth, however, sometimes are couched in terms of biological determinism; for ex- ample, in The Population Bomb Ehrlich writes: “our urge to reproduce is hope- lessly entwined with our other urges”.4 _{In essence, while humans (or Culture)}

are advanced as the cause of environmental change, they are not really consid- ered to be independent agents; rather, they are hostages to biological urges.

Malthusian and Boserupian explanations are particularly influential in the case of modern Africa because the continent has the highest rates of natural population increase. Two issues, however, complicate matters. First, a number of the African countries that are listed amongst those with the highest deforest- ation rates, including Gabon, Congo (Brazzaville) and the Democratic Republic of Congo, are underpopulated.5 _{Second, research suggests that Africa’s popu-}

lation began to grow only in the 1940s or 1950s, although environmental de- gradation related to population growth, notably deforestation and soil erosion, became major concerns in the late 1920s and the 1930s.6 _{Population move-}

ments, however, led to the relative redistribution of the existing population, with concentrations of specific groups of people and subsequent population

Reversing the Spiral. On Boserup-inspired approaches see Boserup, The Conditions of Agricultural Growth; Pingali, Bigot and Binswanger, Agricultural Mechanization and the Evolution of Farming Systems in Sub-Saharan Africa; Okafor and Fernan- des, “The Compound Farms of South-Eastern Nigeria: A Predominant Agroforestry Homegarden System with Crops and Small Livestock”; Tiffen, Mortimore and Gichuki, More People, Less Erosion; Quisumbing and Otsuka, Land, Trees and Women, pp. 43-79; and Siebert, “Beyond Malthus and Perverse Incentives, pp. 19- 21.

3 _{For critiques of the population pressure models, see, for example, Cordell and}

Gregory, African Population and Capitalism, pp. 14-15; J. Koponen, “Population: A Dependent Variable”, and G. Maddox, “Environment and Population Growth in Ugogo, Central Tanzania”; Fairhead and Leach, Reframing Deforestation, pp. 13, 178; Mazzucato and Niemeijer, Rethinking Soil and Water Conservation, pp. 124- 164.

4 _{Ehrlich, The Population Bomb, pp. 31-32. For a critique, see Koponen, “Population:}

A Dependent Variable”, and Maddox, “Environment and Population Growth”.

5 _{Myers, Deforestation Rates, pp. 20-23, 45-47; Westoby, Introduction to World}

Forestry, p. 109.

6 _{Koponen, “Population: A Dependent Variable”, and Maddox, “Environment and}

Population Growth”; Notkola and Siiskonen, Fertility, Mortality and Migration in Subsaharan Africa, chap. 9; Headrick, Colonialism, Health and Illness in French Equatorial Africa, pp. 89, 194-195, 385-394.

pressure in some areas, and depopulation and decreasing population pressure in others. Thus, until the 1940s or 1950s, population movement in Africa may have been a more critical variable than population growth, and indeed mi- grations continue to play a major role in the population dynamics of modern Africa and consequently in environmental changes.7

In pre-World War II north-central Namibia’s Ovamboland Native Reserve, environmental change was driven more by population movements than by natural population growth. Insecurity and security concerns are key to ex- plaining why, how, where and when populations movements are associated with deforestation. In the late 1800s through the early 1920s, a general climate of insecurity caused people to concentrate in nucleated wooden fortifications – tree castles – for purposes of defense. The fortifications were extensive and elabo- rate, and building them required enormous amounts of wood. From the 1920s onward, improved political security allowed people to fan out from population centers into the surrounding wilderness. As settlers moved into the wilderness, however, they faced a new threat: wild animal populations that had rebounded from 1890s lows. To protect lives and livelihoods, the settlers retained the prac- tice of constructing fortified homesteads, contributing to a high consumption of woody vegetation and deforestation.