VIEWS: 19 PAGES: 9 POSTED ON: 12/28/2011
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 Deforestation 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? Deforestation? • In hillside areas increases in population density induce tree planning. - 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 increases. - 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. Density • As wages decrease, farmers are more likely to invest in labor-intensive land innovation techniques such as terrace banks • 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 !