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									Has Population Growth Degraded the
Quality of our Natural Resources   ?
 *Population growth is neither necessarily bad nor good

 * The effects of increases in population density on the
 quality of natural resources depend on particular economic
 and institutional conditions

Arable Land
Livestock Populations and Grazing Areas
Nutrient Depletion and Soil Erosion

                       Farm Wages
                       Farm and Family Size
                       Nonfarm Income Opportunities
                       Property Rights
What happens to arable land when population density increases?

• In hillside areas increases in population density induce tree

       - The opportunity cost of vacant space in terms of
  forgone tree products increases as farm size decreases and
  the number of household members working per farm

       - Non-farm income opportunities also increase tree
  density as farmers plant trees to retain land-use rights while
  working elsewhere.
  Livestock Population and Grazing areas
                                           •   At higher levels of population density,
                                               feeding methods become labor intensive
Population                                     and grazing areas decrease.
                                           •    As wages decrease, farmers are more
                                               likely to invest in labor-intensive land
                                               innovation techniques such as terrace
                                           •   Farm and family size increases lead to
                                               higher livestock densities and lower
                                               grazing areas
                                           •    Reductions in property rights can
                             Livestock         stimulate non-owner farmers to invest in
                             Density           land improving production techniques
                                               when grazing areas decrease
      Negative Scenario:
      Population growth → Increases in Animal Density → More Grazing Areas →
      Decreased Biodiversity and Resource Runoff
  The effects of microeconomic conditions on cropland

    •   Increases in population density are negatively correlated with length of
        fallow and positively correlated with cropping frequency
    •   Increases in agricultural activity lead to extensive fertilizer use
    •   The transition from short to long fallow systems causes soil erosion serious
        de-vegetation, and the destruction of virgin ecological niches

• As wages decrease, farmers are more likely to use organic and non-purchased inputs
• When landholdings decrease as population density increases, farmers are more likely to
   invest in soil conservation systems
• Increases in property rights make land scarcer and therefore the expected return on land
  conservation structures increases
Conclusions :
• Rural population increases are not directly associated with natural
  resource degradation

• Increases in population density can be beneficiary when farmers invest
  in land-management systems

• However, slowing down the rate of population growth can have a
  positive impact since it allows more time for technology to develop
  and for people to adapt to new production processes

• Most studies agree that there is a U- shape relationship between land
  productivity and land-labor costs. Although, changes in the cost of
  inputs other than land or labor can induce changes in land quality
Policy Recommendations
•   Findings indicate that innovation methods are more likely to occur when
    property rights decrease.

•   Land management institutions should build on local processes of innovation
    and encourage cooperation among farmers.

•   Policies that increase non-farm income opportunities can alleviate poverty but
    can lead to watershed degradation when innovative methods are abandoned, in
    which case policies need to encourage tree planting.

•   Policies should seek to protect unsettled areas, since under no circumstances
    higher population density led to increases in biodiversity
The End !

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