Read chapter 2 Population, Land Use, and Environment: A Long History: This Limited documentation of the relation between population change and land. Demographic change was thought to be the most major driver of land use change although there were several interacting factors involved. In studying the population and land use relationship, it is essential to consider . However, the relationship between percentage changes in population and land.
Within the urban category, industrial sites produce somewhat less value per land unit compared to private and public services.
Two nonurban land use activities are at the level of industry and services: On Mauritius, their production of value added per land unit exceeds all other land use categories, including the urban ones.
The ratio of value added per land unit between the extremes, tourist hotels and sugar cane, is 70 to 1. On average, urban activities produce at least 20 times more per land unit as compared to rural activities.
With such variations it is obvious that rankings of used land area Figure 3 versus the absolute value produced or consumed in that land area will differ Figure Page Share Cite Suggested Citation: About 80 percent of the value produced or consumed is based on activities that take place on 10 percent of the land area.
Only sugar cane production still rates high both in the amount of land used and the absolute value added of its production.
This simple relationship between value added and used land is only a crude indicator of the direction and strength of the economic forces driving changes in the land use pattern. If everything else is equal this relation would serve as an estimate of the land rent. But everything else is not equal. The amounts and costs of capital and labor, the two other production factors besides land, vary considerably among production sectors. For example, although other types of agriculture e.
If the level of income per capita, and thereby of wages is high enough, and if the land is not required for other e. Judged from a traditional carrying capacity concept, Mauritius, with its very high population density, could be expected to be in trouble.
It would not be easy to feed its population at the present level of consumption per- Page Share Cite Suggested Citation: Obviously, the present economic base of Mauritius is not a traditional agricultural one but rather is that of an urban society with export industry and services as its main means of production.
Perhaps Mauritius never was a subsistence economy. Ebony, sugar, spices, textiles, and tourist services are all export products. In traditional agriculture one produces goods for immediate domestic consumption. Sugar cane has, since long before the reduction in fertility and the economic growth of recent decades, dominated agricultural land use on Mauritius.
From a subsistence point of view sugar cane production and sugar milling are more similar to an export industry than to domestic agriculture. The whole purpose of export-oriented production is to get a valuable asset for use in trading on the world market, thereby importing what otherwise had to be produced locally for domestic consumption. Therefore it is not the direct need for food crops, etc. Still, at any level of economic development, sufficient quantities of food have to be produced somewhere.
The question for a small region or country is why do it themselves, domestically?Population growth and food supply-- bottom up or top down? - Tom Wilson - TEDxTucsonSalon
Suppose it would be feasible to increase the present level of food self-sufficiency from one-third to almost percent by converting, say, another 2—4 percent of the total land Page Share Cite Suggested Citation: Due to most evaluations of the profitability of food crops versus sugar cane, the alternative of sugar cane or industrial or tourist production on that land would have created resources to buy both the food needed and other goods and services on the world market.
So why not continue to explore the relative economic advantages for production and land use that have evolved based on sugar, tourism, textiles, and electronics? Other factors will be important to a move toward agricultural self-sufficiency, such as lower sensitivity to world market changes, possible negative environmental consequences of sugar cane or textile production, or possible cultural and political reasons.
Additional work has demonstrated that such equilibria, if they exist, are exceedingly dynamic.
Particular emphasis is placed upon the importance of disturbance of the landscape by episodic events of large magnitude such as hurricanes, fires, and floods. Each major event may result in a new potentially stable assemblage of vegetation. The sequence of changes following disturbance and the duration of an apparently stable configuration are difficult to predict. As these disturbances interact with human activities, isolation of the significance of one or the other influence is particularly difficult.
Another important element in evaluating the significance of the impact of human activities on the landscape involves the concept of recovery and resilience. Resilience refers to the ability of the landscape or ecological system to rebound from the impacts of instant or progressive change. Recovery refers to the process by which an absolute change, whether achieved rapidly or slowly, can be mitigated or reversed to return a system to its prior undisturbed state.
Unfortunately, little information is available about recovery processes or about the extent to which initial conditions in the environment and in the land itself have been altered over long periods of time. Dramatic examples of erosion and soil losses where farming is practiced on very steep slopes without terracing are important and easily documented Eckholm, They cannot be extrapolated to different settings.
It is much more difficult to recognize slower or more subtle changes over time or to evaluate the likelihood that such changes can be reversed. Dregnean astute soil scientist with worldwide experience, estimates that about 70 percent of "global drylands" are degraded, with rangelands suffering the most extensive degradation. He notes, however, that, "data on land degradation are so difficult to obtain that a study in countries is largely based on a few maps, a little experimental data, observation and even anecdotes" Dregne, Until recently, relatively little interest was expressed in the off-site Page 26 Share Cite Suggested Citation: While sedimentation of waterways was important historically, current interest concerns organic and inorganic substances attached to sediment particles.
Population Growth and its Impact on Land Use
Metals, petroleum products, pesticides, herbicides, and all of the materials used in modern industrial societies can be found in the accumulated sediments. A broad survey of landscape change effected by human beings throughout human history clearly demonstrates that human beings have significantly altered the natural landscape over much of the globe. In many instances such change has degraded soil and water. Elsewhere the ''made'' landscape has been made more productive, if not more diverse.
Much less clear is the degree to which degradation of these resources is reversible in whole or in part. Whether this is a desirable objective is a separate question.
Even less clear is the degree to which population numbers or rates of change have been directly or indirectly the driving force behind degradative or restorative processes. To the extent that the dryland degradation reported by Dregne is recent and expanding, more of the same suggests further losses. Similar statements apply to exploitation of steep lands and areas denuded of vegetation and exposed to intense rainfall. Projections, paraphrasing Dubos, are not predictions.
Although degradative trends are probably reversible in many regions, it is worth noting that soil conservation practice in Africa and in many parts of Latin America and Asia has probably been retreating rather than advancing in the last several decades. Social and economic factors rather than knowledge or technology appear to determine this trend Blaikie, Under some circumstances "conservation pays," but much evidence demonstrates that conservation often "costs" someone, whether an individual farmer or a government.
While they do not discuss degradation or deterioration in the land resource, Buringh and Dudal projected changes or losses in land uses between and They note expected declines in some highly productive agricultural lands due to urban expansion, but agricultural expansion is expected to occur at the expense of forests and grazing land. Whether such conversions are viewed as positive or negative, contributions to society and the environment depends on the long-term values placed on these resources.
Limited documentation of the relation between population change and land change lends caution to extrapolation into the future of observations of yield declines where sedentary agriculture replaces shifting cultivation, where salinization and waterlogging accompany modern irrigation systems, or where agriculture replaces forests as population grows. The modern scene is not like the past.
Both the rate and the magnitude of population change are large, the magnitude unprecedented in history. Although fertility is declining in many parts of the world, the increase in world population of about I billion people in the last decade is equal to the total world population in Raven et al. The evidence is partly historical, as illustrated in M.
Gordon Wolman's paper, which shows that land use patterns over the last 6, years are associated with the expansion of the human population. These associations have existed for over three decades in Thailand as documented in Theodore Panayotou's case study. There is also cross-sectional evidence, as illustrated in Richard Bilsborrow and Martha Geores's paper, that notes a correlation between a country's population density and the percentage of its arable land that is used in production.
Finally, evidence based on Ester Boserup's model and research shows how population increases induce people to cultivate additional land or to farm their present land more productively, as demonstrated in Robert Evenson's paper. Most of the changes in land use associated with very rapid population growth are likely to be disadvantageous for human beings. The changes that Boserup and others have described show that as populations grow, the technology required to maintain output is more expensive and requires more investment and labor.
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These are mainly the direct, on-site costs. There are also indirect, off-site costs that may be as great or greater than the on-site costs. They include salinization resulting from irrigation and contamination of common property resources resources that are commonly owned, but without rules or regulations governing their use from fertilizer use.
Many of the workshop participants thought the most important way to offset these costs associated with rapid population growth was through institutional change, such as property rights and agricultural research, as noted in Vernon Ruttan's paper.
Whether these effects completely or partially offset the problems created by rapid population growth cannot be determined for the general case. But it is difficult to demonstrate an instance in which the offsetting effects are great enough to make the population as well off in terms of its land use patterns as it would have been with slower population growth. Evenson's paper shows that North India is not such an instance. Population growth is not the only, or in many cases, the most important influence on land use.
Other influences include technological change and changes in production techniques—which can be exogenous or, in some situations, endogenous or partly induced by population growth. National and international markets for goods and agricultural products clearly influence patterns of land use, as do government regulation and tax policies or the absence thereof.
Income inequality was repeatedly mentioned by the workshop participants; clearly, it is an important factor in land use patterns in Honduras, as demonstrated in the Billie DeWalt, Susan Stonich, and Sarah Hamilton case study. Inequality itself, however, is in part influenced by rates of population growth. In analyzing the question of whether population growth is the most Page 11 Share Cite Suggested Citation: What has been the relative influence of population growth on land use in the past?
If the goal is to alter patterns of land use in the future, would reducing fertility be one of the most cost-effective ways to intervene?
Family planning programs put in place today will have their primary effect on the margin, which is the new births averted in the future. Looked at another way, however, population momentum simply means that if population policy is to have a major effect on future population growth patterns, it must begin sooner rather than later.
Because the effects of population growth on land use depend on many factors, case studies that clearly delineate the relative role of these factors are needed. Among these conditioning factors are markets for agricultural and forestry products, land tenure systems, soil quality, climate, and capital markets. The workshop case studies suggest that population growth is most likely to result in land degradation when land is held in common without rules governing its access, when production is mainly for subsistence, and when the soil is fragile and rainfall light.
Under these conditions, fast population growth clearly creates potential for producing soil degradation. Parts of Africa may fit this pattern, but the northern Nigeria case study by Michael Mortimore shows that the farmers have adapted quite well to the doubling of their population.
With clear property rights, robust soils, and efficient markets, population growth is less likely to result in land degradation. Under these conditions, rapid population growth, which results in larger markets for agricultural products, gives land owners incentives to protect soil quality, which they are able to do by borrowing in relatively efficient capital markets. At the same time, land ownership provides collateral for the borrowing needed to invest in the protection of soil.
Most real situations are somewhere between these two extreme scenarios, and more research is needed on the role of these conditioning factors in different areas.
Rapid population growth is likely to make the survival of other members of the animal and plant kingdom more difficult. Accompanying rapid population growth in the past has been greater species loss and a higher attrition within species than would have occurred in the absence of human expansion.
It is difficult to place an exact value on this loss, particularly with regard to its importance for humans. There are widely varying views as to the weight that humans should attach to the welfare of other species. It is clear that the preferences for those species are not presently being reflected in any market mechanism, although the survival of several species is debated in the political process.