The first strategy discussed was land sparing farming, which focuces on intensive agriculture (high chemical inputs, irrigation, machinery, etc). This creates an environment harsh to most forms of life, but the high yield it generates preserves wilderness that would otherwise be converted to agriculture. In land sparing there is a strong contrast between land for agriculture and land for biodiverstiy, and the land itself seems to be essentially homogenous.
The second strategy discussed was wildlife friendly farming which focuses on the reduced use of chemicals, and the landscape itself is more heterogeneous from the planting of buffer zones. The agriculture yields tend to be lower per unit area; therefore, higher yields require more land.
So which is better? Each strategy has its advantages and disadvantages. One thing to consider is the landscape's species turnover. In landscapes with little species turnover, land sparing has benefits for species that are sensitive to even low intensity agriculture. On the other hand, land sparing can be problematic in landscapes with high species turnover, because intensification anywhere is likely to result in substantial loss of species. Topography is another thing to consider since it affects the likelyhood of either strategy to be practiced. Wildlife friendly farming is more likely to occur in landscapes with complex topography where industrial agriculture and its machinery are difficult to implement. The condition of land needs to be considered also. Land sparing farming is not likely desireable in areas of poor nutrients, since the cost would be high and the damage to such systems likely severe.
The optimal strategy is not intuitively obvious with each having its own set of trade-offs. Nonetheless, I tend support the land-sparing strategy. The first reason for supporting land-sparing farming is that many species, especially those of conservation concern, seem to exhibit a convex density-yield function; therefore, they exist in areas where agriculture is extremely low (Karieva et al. 2011). Another reason for my support is the studies conducted by Kleijn et al. in 2001. They found only small benefits of agri-environment schemes that included actions ranging from land set-asides to delayed plowing for the sake of bird nesting to enhancement of diverse vegetation at the edge of fields. This study set off a firestorm of controversy the European Union had invested $25 billion US dollars in these schemes. Adding fuel to the fire, a later review of 62 separate studies by similarly found minimal benefit (Kleijn and Sutherland 2003).
Most people would side with wildlife-friendly farming when
considering the external costs of both strategies. However, it’s important to
note that the external effects of agriculture are a product of both intensity
and area. Land-sparing farming has high external environmental costs per unit
area, but they must be weighed against reduced external costs per area spread
over a larger land area. For example, an abundance of low yield farms could
increase habitat fragmentation. Also, I believe that the externalities from
land-sparing farming, such as pesticide drift and nutrient runoff, can open
doors for new industries that create jobs from the production of sustainable
intensification products and practices. Low-external-input (LEI) agriculture
can make the use of fertilizers and other inputs more efficient and many
farmers are now adopting integrated pest management techniques that help reduce the
use of synthetic pesticides (Karieva et al. 2011).
Beyond utilitarian considerations, the wildlife-friendly
farming/land-sparing debate raises philosophical questions about protecting
biodiversity. Though I am not that familiar with the debate, it reminds me of
the 19th century debate between preservationists and conservationists. Preservationists
advocated unaltered nature for its own sake, while the latter argued that
nature should be managed for human benefit. In the present context, land
sparing might permit larger areas of unaltered nature in the form of natural
parks and wildlife preserves, while wildlife-friendly farming would permit land
use that is beneficial to humans at minimum cost to biodiversity. It is
interesting to me how contemporary environmentalists sort out along
philosophical lines. In general, it seems that those with a biological
inclination lean toward wildlife-friendly farming, while developmental
economists and agriculturalists advocate land sparing.
CITED:
Fischer, J., B. Brosi, G. C. Daily, P. R. Ehrlich, R. Goldman,
J. Goldstein, D. B. Lindenmayer, A. D. Manning,
H. A. Mooney, L. Pejchar, J. Ranganathan, and H. Tallis. 2008. Should
agricultural policies encourage land sparing or wildlife-friendly farming?
Frontiers in Ecology and the Environment 6: 380-385.
Kareiva, Peter and Michelle Marvier. 2011. Conservation
Science, balancing the needs of people
and nature. Roberts and Company, Greenwood
Village , Colorado.
Kleijn D., F. Berendse, R. Smit, and N.Gilissen. 2001.
Agri-environment schemes do not
effectively protect bio-diversity
in Dutch agriculture landscapes. Nature 413:723-725.
Kleijn D. and W.J. Sutherland. 2003. How effective are
European agri-environment
schemes in conserving and promoting biodiversity?
Journal of Applied Ecology 40: 947-969.
MA (Millennium Ecosystem Assessment). 2005. Ecosystems and
human well being: synthesis
report. Washington , DC :
Island Press.
