Small family farms in tropics can feed the hungry and preserve biodiversity

Feb 22, 2010

Conventional wisdom among many ecologists is that industrial-scale agriculture is the best way to produce lots of food while preserving biodiversity in the world's remaining tropical forests. But two University of Michigan researchers reject that idea and argue that small, family-owned farms may provide a better way to meet both goals.

In many tropical zones around the world, small family farms can match or exceed the productivity of industrial-scale operations, according to U-M researchers Ivette Perfecto and John Vandermeer. At the same time, smaller diversified farms are more likely to help preserve biodiversity in undergoing massive amounts of deforestation, Perfecto and Vandermeer conclude in a paper to be published online Feb. 22 in the (PNAS).

"Most of the tropical forest that's left is fragmented, and what you have are patches of forest surrounded by agriculture," said Perfecto, a professor at the School of Natural Resources and Environment. "If you want to maintain biodiversity in those patches of forest, then the key is to allow organisms to migrate between the patches.

"And small-scale family farms that adopt sustainable agricultural technologies are more likely to favor migration of species than a huge, monocultural plantation of soybeans or sugar cane or some other crop."

Some ecologists have suggested that the history of eastern North American forests provides a preview of what's likely to happen in the tropics. European colonization of eastern North America led to massive deforestation that accompanied the expansion of agriculture. Later, industrialization drew people to cities from the rural areas, and the forests recovered.

This scenario is known as the forest transition model. It has been argued that if a similar progression occurs in the tropics, then the decline in rural populations would make more land potentially available for conservation. A corollary of the forest transition model states that if you consolidate agriculture into large, high-tech farms, productivity increases and more land is freed up for conservation.

But after reviewing case studies from Costa Rica, El Salvador, Panama, Argentina, Brazil and Mexico, Perfecto and Vandermeer conclude "there is little to suggest that the forest transition model is useful for the tropics" and that it "projects an overly optimistic vision."

Instead, the U-M researchers propose an alternative model, which they call the matrix quality model. They say it provides a solid foundation for conservation planning in tropical regions.

If you think of the fragments of remaining tropical forest as islands in an ocean of agriculture, the ocean is what Perfecto and Vandermeer call the matrix---it's the area between the patches of undisturbed natural habitat.

A high-quality matrix is one that enables plants and animals to migrate between the remaining patches of forest, increasing the likelihood that a given species will be able to survive, helping to preserve biodiversity.

Small, family-owned farms that use agroecological techniques come closest to mimicking natural forest habitat, thereby creating corridors that allow plants and animals to migrate between forest fragments. Agroecological techniques can include the use of biological controls instead of pesticides, the use of compost or other organic matter instead of chemical fertilizers, and the use of agroforestry methods, which involve growing crops beneath a canopy of trees or growing crops mixed with fruit trees such as mangoes or avocados.

"If you're really interested in conserving species, you should not just concentrate on preserving the fragments of natural habitat that remain, even though that's where many species are," said Vandermeer, a professor of ecology and evolutionary biology and a professor at the School of Natural Resources and Environment. "You also need to concentrate on the areas between the fragments, because those are the places that species have to migrate through."

Vandermeer said he advocates the break-up of large-scale farms in the tropics, as well as incentives to encourage "a large number of small-scale farmers, each managing the land to the best of his or her ability, using agroecological techniques."

Perfecto said these goals are in line with the findings of the 2009 International Assessment of Agricultural Knowledge, Science and Technology for Development synthesis report. The report concluded that small-scale, sustainable farms are the best way to alleviate world hunger while promoting sustainable development. Perfecto was one of the report's authors.

Explore further: Invasive vines swallow up New York's natural areas

Related Stories

Another reason to drink a nice cup of shade-grown joe

Dec 22, 2008

A new study published in the December 23rd issue of Current Biology, a Cell Press publication, reveals another "eco-friendly" reason to select shade-grown coffee over beans that were grown in the sun: Shade coffee farms ...

Biofuels and biodiversity don't mix, ecologists warn

Jul 09, 2008

Rising demand for palm oil will decimate biodiversity unless producers and politicians can work together to preserve as much remaining natural forest as possible, ecologists have warned. A new study of the potential ecological ...

Recommended for you

Invasive vines swallow up New York's natural areas

5 hours ago

(Phys.org) —When Antonio DiTommaso, a Cornell weed ecologist, first spotted pale swallow-wort in 2001, he was puzzled by it. Soon he noticed many Cornell old-field edges were overrun with the weedy vines. ...

Citizen scientists match research tool when counting sharks

20 hours ago

Shark data collected by citizen scientists may be as reliable as data collected using automated tools, according to results published April 23, 2014, in the open access journal PLOS ONE by Gabriel Vianna from The University of Wes ...

Researchers detail newly discovered deer migration

Apr 23, 2014

A team of researchers including University of Wyoming scientists has documented the longest migration of mule deer ever recorded, the latest development in an initiative to understand and conserve ungulate ...

How Australia got the hump with one million feral camels

Apr 23, 2014

A new study by a University of Exeter researcher has shed light on how an estimated one million-strong population of wild camels thriving in Australia's remote outback have become reviled as pests and culled ...

Former Iron Curtain still barrier for deer

Apr 23, 2014

The Iron Curtain was traced by an electrified barbed-wire fence that isolated the communist world from the West. It was an impenetrable Cold War barrier—and for some inhabitants of the Czech Republic it ...

Humpback protections downgrade clears way for pipeline

Apr 22, 2014

Environmentalist activists on Tuesday decried Canada's downgrading of humpback whale protections, suggesting the decision was fast-tracked to clear a major hurdle to constructing a pipeline to the Pacific ...

User comments : 4

Adjust slider to filter visible comments by rank

Display comments: newest first

Caliban
1 / 5 (1) Feb 22, 2010
What is needed to make this model work is a robust, well developed distribution infrastructure. Samll farms, away from population centers, can only provide locally. In order to be able to sell excess produce to a wider market
at a profit, they have to be able to get it there before it spoils. A capillary network of very small-gauge trains would probably do the trick- or something on that order. A second way to make this type of agriculure sustainable is to combine the traditional forms of Agri(crops, animal husbandry, orchards) with Forestry- and thereby provide a continuum all under one roof- so to speak. The main problem still remains distribution, however.
Birger
not rated yet Feb 23, 2010
Ethiopia has seen an increasing productivity, after receiving support -and education- for smaller farms, starting in the northern Tigrae province. This shows you do not have to copy European/US large-scale agriculture for Africa to feed itself.
marjon
not rated yet Feb 23, 2010
Instead of selling raw products, farmers should process their products for final sale.
Local dairies in NE make and sell homemade ice cream.
A water buffalo farm in VT makes and sells yogurt from their cows.
I see new technology for freeze drying fruit like strawberries and other tropical fruit.
When energy can be decentralized, using solar, wind, solar power satellites and/or small nuke plants, small farmers and others could do quite well.
Caliban
1 / 5 (1) Feb 24, 2010
Right.
But you also have to feed the community, too- the people that work on the farm, repair the tools/machinery, teach your children, etc, et c.

More news stories

Cell resiliency surprises scientists

New research shows that cells are more resilient in taking care of their DNA than scientists originally thought. Even when missing critical components, cells can adapt and make copies of their DNA in an alternative ...

Team reprograms blood cells into blood stem cells in mice

Researchers at Boston Children's Hospital have reprogrammed mature blood cells from mice into blood-forming hematopoietic stem cells (HSCs), using a cocktail of eight genetic switches called transcription factors. The reprogrammed ...