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 tropical regions undergoing massive amounts of deforestation, Perfecto and Vandermeer conclude in a paper to be published online Feb. 22 in the Proceedings of the National Academy of Sciences (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.
The PNAS article by Perfecto and Vandermeer is part of a special report in the journal about solutions to the world food crisis. Perfecto, Vandermeer and Angus Wright discuss the links between agriculture, conservation and food sovereignty in their book "Nature's Matrix," published last year by Earthscan.
Jim Erickson | EurekAlert!
Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences