Conservation biology and agroecology: De un Pajaro las dos alas.

Abstract

One of the strategies used by conservation agencies and governments to curb biodiversity loss has been to establish priority areas where species richness and levels of endemism are high. The strategy to purchase land and protect it has been based primarily on the idea that the conversion to agriculture is the main cause of habitat loss for wildlife and on the assumption that local people and their livelihood practices constitute the most important threat to biodiversity conservation. However, over the last decade, it has become obvious that these efforts to reduce the loss of biodiversity are not working and that the assumptions on which the main conservation efforts are based ignore the role of external factors related to political economy, as well as the vast array of livelihood practices that maintain and even increase biodiversity at the landscape level. In this paper, I propose various reasons to explain the failed strategy. The importance of agriculture for the conservation of biodiversity has three main components: 1) the matrix that surrounds protected areas is composed primarily of a mosaic of agricultural and other managed systems (this means that particularly in a fragmented landscape, migration to and from "natural" habitat fragments must take place within the agricultural matrix), 2) agroecosystems per se can be important habitat for wildlife, and 3) human communities inside and outside protected areas engage in productive activities that can not be ignored when the protected area is established. The "problem" with agriculture is not agriculture per se, but rather the intensification of agricultural and livestock systems. The major drop in biodiversity occurs with the "intensification" of agriculture, not with its initiation. The main challenge for the new generation of conservationists is to incorporate agriculture and other managed systems as an integral part of conservation policies, and vice versa, to integrate biodiversity conservation into the development of agricultural policies. Part of the challenge ahead is the recognition that agroecology and conservation biology are both essential components of an integrated policy and that they are, metaphorically speaking, the two wings of the biodiversity conservation bird.

**********

The loss of biodiversity became frontpage news more than ten years ago at the United Nations Conference on Environment and Development in Rio de Janeiro, Brazil. Heads of states of more than 182 nations signed the United Nations Convention on Biological Diversity (UNCED) to confront the crisis. Ten years later, the possibility of mass extinctions without precedence is still front-page news, with little evidence that progress has been made. In 2002, for the anniversary of the UNCED, newscasts at CNN, BBC, and others covered the lack of progress on curbing biodiversity loss. According to a recent survey of 400 scientists commissioned by the American Museum of Natural History, the majority of the nation's biologists are convinced that a "mass extinction" of plants and animals is underway and agree that the loss of biodiversity is one of the most pressing environmental problems facing us in the new millennium (American Museum of Natural History 2003).

One of the strategies used by conservation agencies and governments to curb biodiversity loss has been to establish priority areas where species richness and levels of endemism are high, the so-called "hot spots of biodiversity" (Myers 1988; Cincota and Endelman 2000). The focus within these areas has been to purchase land and set it aside through the establishment of protected areas. The establishment of protected areas is hardly a new concept, with examples of sacred groves and recreational areas established throughout history and in all areas of the world. In India for example, sacred groves were established millennia ago for the protection of wildlife (Gadgil and Ramachandra 1993) and local farming communities in Mexico routinely set aside nature reserves for watershed protection and recreation. However, the first time that a protected area was created by national decree was Yellowstone National Park in 1872 (Merchant 1993). Yellowstone became a model for the establishment of reserves and national parks all over the world. In Brazil, the first protected nature reserve was established in 1911, and the first National Park, in 1930. Since then, 35 national parks, 23 biological reserves and six ecological reserves have been created in Brazil, covering 15 million hectares of land protected at the national level. Similarly, in Mexico, the first National park, Parque Nacional Desierto de los Leones, was established in 1917. During the presidency of Lazaro Cardenas (1934-1940), who's populist development agenda was based partially on conservation of natural resources, 32 national parks were established in Mexico (Simonian 1995). Today, there are 93 protected areas, including more than 50 National Parks, with 11.7 million hectares representing six percent of the land under protection (Simonian 1995; Vargas Marquez 1984). Worldwide, there are approximately 17,000 nature reserves covering nearly ten percent of the earth's land surface, and with the establishment of private reserve, this amount is increasing (McNeely and Scherr 2003; World Conservation Monitoring Center 2000). However, over the last decade, it has become obvious that these efforts to reduce the loss of biodiversity are not working. In this paper, I propose various reasons to explain the failed strategy. Unlike some main stream conservationists, who argue that we need to expand protected areas and protect them by whatever means necessary (Terborgh 1999; Oates 1999), I argue that the failure is precisely because of the strategy of establishing reserves and the particular focus that these efforts have taken.

The Failed Strategy: Creating Nature Reserves

The strategy to purchase land and protect it has been based primarily on the idea that the conversion to agriculture is the main cause of habitat loss for wildlife. The focus of this conservation strategy has been on charismatic megafauna and on so-called "pristine" habitats. Such a focus is unfortunate since it effectively ignores everything outside of the protected areas, includ within managed ecosystems. Although many conservation organizations have realized this since the mid eighties and have responded with the implementation of so-called Integrated Conservation and Development Projects (ICDP), the assumptions of most ICDP programs have not really deviated from the underlying assumption that local people and their livelihood practices constitute the most important threat to biodiversity conservation (Hughes and Flintan 2001). This assumption ignores the role of external factors related to political economy (such as pressures to pay external debt, construction of roads, and transmigration programs), as well as the vast array of livelihood practices that maintain and even increase biodiversity at the landscape level, to say nothing of recent advances in the science of ecology associated with mechanisms of extinction and metapopulation theory.

The Focus on Charismatic Megafauna

All of us are familiar with the beautiful poster and the campaigns to protect pandas, elephants, gorillas, tigers, jaguars, and other charismatic organistas. If the interest is to conserve the diversity of life on our planet, the focus on mammals and other vertebrates is quite misguided. Based on conservative estimates of actual numbers of species, all the vertebrates on our planet represent only 0.4% of all the diversity of life (Groombridge 1992). Even plants, which were thought to be quite diverse, represent at most 14% of all the described species, with some estimates putting the figure closer to 2.4% (based on the rate of encountering new species). On the other hand, arthropods represent at least 50% of all species, with beetles alone accounting for 25% of all estimated species (Groombridge 1992). The British biologist, J. B. S. Haldane, when asked what he had been able to learn about God during all his years of studying nature, responded, "the creator, if he exists, has an inordinate fondness for beetles."

Recently, in efforts to call attention to the need to protect biodiversity, ecologists have pointed out the link between biodiversity and ecosystem function. Interestingly, few of these studies even mention charismatic fauna, and most point to the role of soil micro and macro organisms, soil ecosystems being the new frontier in biodiversity studies. Recent studies have documented more than 10,000 different types of fungi and bacteria and 100 to 1000 species of invertebrates in Torsvik et al. 1994).

A quick tally of the posters presented at the XVII Meetings of the Mesoamerican Society for Biology and Conservation in Tuxtla Gutierrez in November 2003 revealed that the bias toward large charismatic organisms has been transmitted to the new generation of scientist (most of the posters presented were by undergraduate and graduate students from Mexico and Central America.). Out of 159 posters examined, 54.1% were on vertebrates, mainly mammals and birds; 35.2% were on plants and forest ecosystems, and only 10.7 percent were on invertebrates, mainly insects (Figure 1).

[FIGURE 1 OMITTED]

The focus on charismatic organisms has been defended on two fronts. First it is assumed that, since most of these organistas need large areas to maintain viable populations, protecting them will effectively protect everything else that lives in the same area. Second, it is argued that people identify more with these organistas and therefore would support programs for their protection However, evidence from several studies suggest that these assumptions are not always true. It seems that most large mammal species need areas that are considerably bigger than the areas that are already available (Redford and Robinson 1991; Bierregaard et al. 1992; Armbruster and Lande 1993; Wilkie et al. 2000), suggesting that it is necessary to think of areas far more expansive than current nature preserves. Furthermore, with some exceptions, most of the flag ship wildlife does not absolutely require pristine habitat to maintain viable populations. What they need are simply areas where they can find food and shelter and not get shot. On the other hand, there is clear evidence that a focus on "poster species," something charismatic to draw attention when placed on a poster, has been effective politically, regardless of its truth value (the Oak forest at Colonial Point, near Pellston Michigan, was protected based on the proposition that it was a pristine forest, which in fact was false).

The Focus on Pristine Ecosystems

We now have considerable evidence that very little, if any, of the wild lands on Earth are pristine. Even in very remote areas of the Amazon, scientists have found evidence of agriculture and human settlements (Roosevelt et al. 1996; Goulding et al. 1996; Heckenberger et al. 2003). It seems that at some point in time since the invention of agriculture 10,000 years ago, humans have occupied almost every corner of our planet. Nevertheless, land conversion to agriculture over the last 100 years has been responsible for the unprecedented loss of forest habitat, and in particular rain forests, where a large percentage of the world's biodiversity is found. This has lead conservation organizations and governments to place most of their resources in the establishment of reserves and protected areas in what are considered "pristine" forests, in attempts to protect what is left of these ecosystems and their biota. Unfortunately, the protection of the "pristine" habitats has been done at the expense of all areas that have already been converted to agriculture or some other managed system, under the false assumption that it is the conversion from natural habitat to managed habitat that is the critical factor in biodiversity loss. As I shall demonstrate below, there is now substantial evidence indicating that this assumption is false in many, if not most, cases.

According to Western and Pearl (1989), 90% of the Earth's land surface is in some sort of managed ecosystem. Although this is an inflated figure that assumes that all lands outside of established reserves have already been transformed somehow, it still points out the fundamental problem of focusing on the so-called "pristine" habitats--we are ignoring a large percentage of the surface of our planet. More conservative estimates based on satellite images revealed that humans actively manage at least hall of the Earth's surface and a large percentage of the rest is under some sort of human influence (Table 1). These data alone underscore the importance of incorporating managed ecosystems into our conservation policies (McNeely and Scherr 2003).

The Importance of Agriculture for Biodiversity Conservation

The need to incorporate agriculture into conservation policies has become clear in recent years due, in part, to the failure of many conservation programs that focus exclusively on protecting habitat for wildlife. However, even the attempts to incorporate rural people into conservation efforts (e.g., ICDPs and related structures), have suffered from the perception that agriculture is the main culprit of biodiversity loss (Hughes and Flintan 2001). The importance of agriculture for the conservation of biodiversity has three main components: 1) the matrix that surrounds protected areas is composed primarily of a mosaic of agricultural and other managed systems (this means that particularly in a fragmented landscape, migration to and from "natural" habitat fragments must take place within the agricultural matrix), 2) agroecosystems per se can be important habitat for wildlife, and 3) human communities inside and outside protected areas engage in productive activities that can not be ignored when the protected area is established.

The Quality of the Matrix

In the last 20 years, one of the most debated issues in conservation biology has been the size and number of protected areas needed to effectively protect biodiversity, the so-called "SLOSS" (Single Large versus Several Small) debate (Wilkox and Murphy 1985), based on the theory of island biogeography (McArthur and Wilson 1967). The main idea is that the equilibrium number of species on an island (or, by extension, in a habitat fragment) is the result of two processes, extinction and migration. The rate of extinction on an island is related to the size of the island, with larger islands having lower extinction rates, and the migration rate is related to the distance from the mainland, with more distant or isolated island having lower migration rates. This theory was developed for physical islands and assumes that the matrix surrounding the island is in hospitable.

The theory of island biogeography has also been used to explain the loss of species within small isolated nature preserves, which are, of course, habitat islands (Diamond 1975; Whittaker 1998). For example, since its establishment in 1883 the 164-hectare Bukit Timah Nature Preserve in Singapore has lost 50% of the tree species that were present when the reserve was established. This is not surprising, since the reserve is small and is completely isolated and surrounded by Singapore's urban center. In this case, the quality of the matrix within which the nature preserve is embedded is very poor.

Extinctions have not only occurred in small reserves but also in large national parks. A study of 14 North America national parks revealed that extinctions have occurred in all except the largest National Parks (Newark 1995). Although some of the reported extinctions could have resulted from invasive species out competing native ones, the quality of the matrix within which these parks are embedded may also be implicated. If a protected area is embedded within a matrix of industrial agriculture or other inhospitable habitat, the rate of migration will be greatly reduced, and, according to the elementary theory of island biogeography, generate a level of extinction commensurate with that lowered migration rate.

An alternative to the theory of island biogeography that has been applied to fragmented habitats is the concept of metapopulations (Levins 1969; Hanski and Simberloff 1997). In a fragmented habitat, populations may be maintained as metapopulations, which is to say, subpopulations within fragments may go extinct but are recolonized from other fragments, thus providing for the entire collection of subpopulations (which is the "metapopulation") to persist even though each of them periodically goes extinct. The role of migration in preventing permanent extinction is evident in both of these theoretical formulations. What has been lacking from these theories and the empirical studies that have followed is the incorporation of the quality of the matrix in determining the rate of migration (Perfecto and Vandermeer 2002; Vandermeer and Carvajal 2001).

In the tropics, most of the remaining forests are highly fragmented (Laurence and Bierregaard 1997). The ability of these patches of forests to maintain biodiversity will depend to a great extent on the quality of the matrix within which they are embedded. For example, in the Sarapiqui area of Costa Rica, the La Selva Biological Reserve is surrounded by a number of forest patches scattered throughout the landscape. However, the matrix that surrounds those patches is frequently composed of tens of thousands of hectares of banana plantations or pastures (Figure 2a). The low quality matrix could reduce or even halt migration of certain organisms from patch to patch, dooming them to extinction within patches. On the other hand, when the matrix is of sufficient quality for migration to occur, local extinctions could be prevented. For example, in the Soconusco area of Mexico, El Triunfo Biosphere Reserve is embedded within a matrix of shaded coffee plantations (Figure 2b). Many smaller patches of forests have been maintained in areas that are too difficult to convert to coffee cultivation. The ability of these smaller patches to maintain forest species depend on the ability of organisms to migrate from patch to patch or from the large reserve to the smaller patches. The shaded coffee plantations provide a high quality matrix through which forest organisms can move (Perfecto and Vandermeer 2002). However, if these plantations are technified and converted to sun coffee (Figure 2c), the migration of some organisms would likely be reduced or halted and local extinctions could occur.

[FIGURE 2 OMITTED]

In summary, the quality of the matrix matters! With a low-quality matrix, rates of migration will be low and species extinction is more likely to occur within fragments, even large ones. The factors that determine the quality of the matrix are going to be different for different groups of organisms. However, some educated guesses can be made. For example, for frugivorous forest bird species, a diverse canopy cover that provides fruits will be important. Agroforestry systems that contain diverse fruit trees could represent a matrix of enough quality to allow migration. Our studies in coffee plantations in Chiapas, Mexico, demonstrate that for ground-foraging ant species, a diverse plantation with more than 50% shade cover represented a high quality matrix while a less diverse shade with less than 20% shade cover was a low-quality matrix. These and other studies strongly suggest that the agroecological matrix should be an essential component of any conservation program design to conserve biodiversity.

Agroecosystems as Habitat for Biodiversity

When we talk about agroecosystems we are referring to a very broad range of agricultural systems and practices all of which have differential impact on biodiversity. A large monoculture of wheat with intensive use of agrochemicals and heavy machinery will have less biodiversity than a mosaic of small diverse organic farms (Vandermeer et al. 1998). Some managed ecosystems, and in particular some tropical agroeforestry systems, have been found to contain very high levels of biodiversity, sometimes comparable to adjacent undisturbed natural systems (Pimentel et al. 1992).

The importance of agricultural landscapes for biodiversity conservation has received significant attention in Europe, where most ecosystems have been altered and transformed to manage systems for millennia. In spite of the fact that agricultural landscapes are the dominant landscapes in Western Europe, the continent has experienced low levels of extinction and most biodiversity seems to have adapted to managed systems. In the UK, where more than 70% of the land surface is farmed, farmland conservation has become one of the main strategies for the conservation of wildlife (DEFRA 2002). However, as traditional farming practices and extensive livestock husbandry are transformed to more intensive systems or are abandoned, these important farmland habitats are disappearing, threatening many species. In the UK, several species of birds are threatened because of the loss of farmland (Gregory et al. 2002), while pesticides have been implicated in the reduction of the populations of others (Campbell and Cooke 1997). According to "Working with the Grain of Nature: A Biodiversity Strategy for England," the main concerns for biodiversity associated with agriculture are related to "the abandonment of traditional practices and the intensification of agriculture" (DEFRA 2002).

In Spain, the dehesa grazing system contain 30% of the vascular plants found in the entire Iberian Peninsula (Pineda and Montalvo 1995), and 135 species have been reported in a 0.1 hectare plot in a dehesa in Andalucia (Maranon 1985). In addition, there are a number of vulnerable and rare bird species whose population viability depends entirely in the structural integrity if this grazing system. However, this system is changing from a pastoral system to a ranching economy threatening the long-term stability of the system and the wild biodiversity that has been maintained for hundreds of years of traditional management (Plieninger and Wilbrand 2001).

In the neotropics an extensive literature has accumulated on the role of diverse shaded coffee and cacao plantations for biodiversity conservation (Perfecto et al. 1996; Moguel and Toledo 1999). However, as in Europe, these traditional systems are being transformed to more intensive farms where the diversity and density of shade is reduced or eliminated altogether (Figure 1c), with dramatic impact on biodiversity (Perfecto et al. 1996; Perfecto and Armbrecht 2003).

It is obvious that the "problem" with agriculture is not agriculture per se, but rather the intensification of agricultural and livestock systems, specifically the intensification that results from the specialization in a few species and varieties of crops and animals, and the substitution of biological processes with agrochemicals. From a variety of studies, it is now evident that the assumption that the main drop in biodiversity occurs at the moment of transformation of the non-managed system to a managed one is false. In a variety of well-substantiated cases the major drop in biodiversity occurs with the intensification of agriculture, not with its initiation (Vandermeer et al. 1998). The community garden and associated areas of fallow land of an Amazonian indigenous community is likely to contain much the same biodiversity as the native forest from which it was carved. But the cattle pasture that replaced those indigenous peoples' farming system probably contains far less biodiversity and, more importantly, represents a matrix of such low quality that interhabitat migration among remaining fragments of natural forest is significantly reduced.

Unfortunately, conservation biologists tend to think of agricultural systems as biological deserts and therefore, the enemy of biodiversity conservation (Vandermeer 2003a). This mainly North American bias has been unfortunate because it has created a protected area/managed ecosystem dichotomy that results in almost opposite goals and strategies for both types of areas. Furthermore, different disciplines are involved in the technical aspects of managing these areas--conservation biologists provide insights for the management of protected areas and agronomists provide insights about managing agricultural areas (Vandermeer 2003a). The dichotomy between the "pristine" and the "managed" reinforce the separation of people from nature (i.e. a romantic notion of nature) and creates barriers for the development of integrated conservation and agricultural policies.

Protected Areas and People

The separation of nature from people has created a philosophical divide between those who do research on biodiversity conservation and those who do research on agroecosystems. Many conservationists still believe that the best way to protect biodiversity is buying land, relocating communities that have traditionally lived and used these areas and fencing it (Terborgh 1999; Oates 1999). However, the last 20 years of failure of this conservation strategy demonstrate that it does not work. Most academic studies conclude that rural communities need to be engaged in conservation strategies and not alienated from them if they are to have a chance to succeed (Wilshusen et al. 2002). There are many examples of rural communities managing their productive systems in ways that conserve or even increase biodiversity at the landscape level (Halladay and Gilmour 1995; Collins and Qualset 1999; Vandermeer 2003b). In particular in the tropics, it is essential to address the problem of land tenure and the lack of access to productive land for the rural poor (Colchester 1994; Vandermeer and Perfecto 1995).

Conclusion

Agriculture should be an integral part of biodiversity conservation, not only because some agroecosystems contain high levels of biodiversity and their intensification represents a significant threat for biodiversity, but also because the conservation of biodiversity within protected areas and fragments of natural habitats depend to a great extent on the quality of the agroecological matrix. In incorporating agriculture into conservation policies careful attention should be paid to the managers of agroecosystems and external forces that push for the intensification of agriculture.

The main challenge for the new generation of conservationists is to incorporate agriculture and other managed systems as an integral part of conservation policies, and vice versa, to integrate biodiversity conservation into the development of agricultural policies. This is already happening to a certain extent in the European Union, but concerns are growing on the potential negative impacts of trade liberalization policies. Part of the challenge ahead is the recognition that agroecology and conservation biology are both essential components of an integrated policy that should be developed with environmental and social justice as guiding principles. They are, metaphorically speaking, the two wings of the biodiversity conservation bird.

Biologia de la Conservacion y Agroecologia: De un Pajaro las dos Alas (1,2)

Resumen

Una de las estrategias usadas por agencias de conservacion y gobiernos para reducir la perdida de biodiversidad ha sido el establecimiento de areas prioritarias en las que la riqueza de especies y los niveles de endemismo son altos. La estrategia de comprar tierra y protegerla se ha basado primariamente en la idea de que la conversion agricola es la principal causa de la perdida de habitat para vida silvestre y bajo el supuesto de que las comunidades locales y sus practicas cotidianas constituyen la mas importante amenaza para la conservacion de la biodiversidad. Sin embargo, en la ultima decada ha llegado a ser obvio que los esfuerzos para reducir la perdida de biodiversidad no han sido exitosos y que los supuestos en los cuales los esfuerzos de conservacion estan basados, ignoran el rol de factores externos relacionados a la politica economica, asi como tambien la vasta diversidad de practicas llevadas a cabo por las comunidades locales que mantienen, y en algunos casos, incrementan la biodiversidad al nivel del paisaje. En este articulo propongo diversas razones para explicar el fracaso de la estrategia para la conservacion. La importancia de la agricultura para la conservacion de la biodiversidad tiene tres componentes principales: 1) la matriz que rodea las areas protegidas esta compuesta primariamente de un mosaico agricola y otros sistemas manejados por el hombre (esto significa que, particularmente en un paisaje fragmentado, la migracion hacia y desde fragmentos de habitat "naturales" debe llevarse a cabo en la matriz agricola), 2) los agroecosistemas per se pueden ser habitats importantes para la vida silvestre, y 3) las comunidades humanas dentro y fuera de las areas protegidas estan involucradas en actividades productivas que no pueden ser ignoradas cuando se establece una area protegida. El "problema" con la agricultura no es la agricultura per se, sino mas bien la intensificacion de los sistemas agricolas y ganaderos. La mayor perdida de biodiversidad ocurre con la "intensificacion" de la agricultura, no con su inicio. El mayor reto para la nueva generacion de medio ambientalistas es incorporar la agricultura y otros sistemas manejados por el hombre como una parte integral de las politicas de conservacion y viceversa, integrar la conservacion de la biodiversidad en las politicas de desarrollo agricola. Parte de este reto en el futuro sera el reconocimiento de que tanto la agroecologia como la biologia de la conservacion son componentes esenciales de una politica integral y que son, metaforicamente hablando, las dos alas del ave de la conservacion de la biodiversidad.

(1) El subtitulo de este articulo proviene de un poema del escritor cubano Jose Marti.

(2) Este articulo esta basado en la platica dada en el XVII Congreso de la Sociedad Mesoamericana para la Biologia y la Conservacion, en Tuxtla Gutierrez, Mexico, Noviembre 4-7, 2003.

La Biologie de Conservation et Agroecologie: De un Pajaro las dos Alas 1,2

Resume

Un des strategies employees par des agences de conservation et des gouvernements pour limiter la perte de biodiversite est du a l'etablissement des aires prioritaires oh la richesse des especes et les niveaux de l'endemisme sont hauts. La strategie d'acheter la terre et de la proteger a ete basee principalement sur l'idee que la conversion en agriculture est la cause principale de la perte des habitats de la faune et sur la pretention que la peuple locale et leur moyens de subsistance constituent la menace la plus importante a la conservation de biodiversite. Cependant, pendant la derniere decennie il est evident que ces efforts de reduire la perte de biodiversite ne fonctionnent pas et que les pretentions sur lesquelles les efforts principaux de conservation sont bases ignorent le role des facteurs extemes lies l'economie politique, aussi bien que le vaste choix des moyens de subsistance qui maintiennent et meme augmentent la biodiversite au niveau du paysage. Dans cet article je propose de diverses raisons pour expliquer la strategie echouee. L'importance de l'agriculture pour la conservation de la biodiversite a quatre composants principaux: 1) la matrice qui entoure les aires protegees se compose principalement d'une mosaique d'agriculture et d'autres systemes controles (ceci signifie que la migration entre les paysages fragmentes et les habitats "naturelles" doit avoir lieu dans la matrice agricole); 2) les agroecosystemes intrinsequement peuvent etre les habitats importants pour la faune; et 3) les communautes humaines dans et hors des aires protegees s'engagent dans les activites productives qui ne peuvent pas etre ignorees quand l'aire protegee est etablie. Le "probleme" avec l'agriculture n'est pas agriculture intrinsequement, mais plutot l'intensification des systemes agricoles et de betail. La baisse principale dans la biodiversite se produit avec l'intensification de l'agriculture, pas avec son commencement. Le defi principal pour la nouvelle generation des conservationistes est d'incorporer l'agriculture et d'autres systemes controles comme partie integrale dans la politique de la conservation, et vice versa, d'integrer la conservation de biodiversite dans la formulation des politiques agricoles. Ce defi reconnait que la biologie d'agroecologie et de conservation sont les deux composants essentiels d'une politique integree.

(1) Le sous-titre de cet article est traduit comme "Deux ailles d'un oiseau." Il est derive de un poem par le cubam Jose Marti.

(2) Cet article est base sur un expose presente au XVII Congres du Sociedad Mesoamericana para la Biologia y la Conservacion, au Tuxtla Gutierrez, Mexique, le 4 - 7 novembre 2003.

Table 1. Percentage of land surface on managed systems (Modified from
McNeely and Scheer, 2003).

SYSTEM                 PERCENTAGE

Agriculture *          10
Mixed Agriculture **   17
Savannas or Pastures   17.5
Tree plantations       1.4
Urban areas            7
Total                  52.9

* Landscapes with at least 60% agriculture.

** Landscapes with a mixture of pastures, forest patches and
agriculture, where agriculture represents at least 30%.

(1) The subtitle of this article is translated as Two Wings of a Bird. It is derived from a poem by the Cuban writer Jose Marti.

(2) This paper is based on a talk given at the XVII Congress of the Sociedad Mesoamericana para la Biologia y la Conservacion, in Tuxtla Gutierrez, Mexico, November 4-7, 2003.

Literature Cited

American Museum of Natural History. Biodiversity in the next millennium. <http://www.amnh.org/museum/press/feature/biofact.html> (October 5, 2003).

Armbruster, P. and R. Lande. 1993. A population viability analysis for African elephant (Loxodonta africana)--how big should reserves be? Conservation Biology 7: 602-610.

Bierregaard, Jr. R. O., T. E. Lovejoy, V. Kapos, A. A. dos Santos, and R. W. Hutchins. 1992. The biology of tropical rainforest fragments. BioScience 42: 859-866.

Campbell, L. H. and A.S. Cooke, eds. 1997. The Indirect Effects of Pesticides on Birds. Joint Nature Conservation Committee, Peterborough.

Cincotta, R. P. and R. Engelman. 2000. Nature's Place: Human Population and the Future of Biodiversity. Population Action International, Washington, D.C.

Colchester, M. 1994. Salvaging Nature: Indigenous Peoples, Protected Areas and Biodiversity Conservation. UNRISD Discussion Paper, Geneva.

Collins, W. W. and C. O. Qualset. 1999. Biodiversity in Agroecosystems. CRC Press, Boca Raton, FL.

DEFRA (Department for Environment, Food and Rural Affairs). 2002. Working with the Grain of Nature: A Biodiversity Strategy for England. DEFRA, UK.

Diamond J. M. 1975. The island dilemma: lessons of modern biogeographic studies for the design of natural reserves. Biological Conservation 7: 129-146.

Gadgil, M. and G. Ramachandra. 1993. The Fissure Land. University of California Press, Berkley, CA.

Giller, K.E., M.H. Beare, P. Lavelle, A., M.N. Izac and M.J. Swift. 1997. Agricultural intensification, soil biodiversity and agroecosystem function. Applied Soil Ecology 6:3-16.

Goulding, M., N. J.H. Smith, D. J. Mahar. 1996. Floods of Fortune: Ecology and Economy along the Amazon. Columbia University Press, N. Y.

Gregory, R.D., N. I. Wilkinson, D. G. Noble, J. A. Robinson, A. F. Brown, J. Hughes, D. Procter, D. W. Gibbons, and C. Galbraith. 2002. The population status of birds in the United Kingdom, Channel Islands and Isle of Man: an analysis of conservation concern 2002-2007. British Birds 95: 410-448.

Groombridge, B., ed. 1992. Global Biodiversity. Status of the Earth's Living Resources. Chapman and Hall, London.

Halladay, P. and Gilmour, D. A., eds. 1995. Conserving Biodiversity Outside Protected Areas. The Role of Traditional Agro-ecosystems. IUCN, Gland, Switzerland.

Hanski, I. And D. Simberloff. 1997. The Metapopulation Approach, its History, Conceptual Domain, Application to Conservation. In Hanski, I. A. and Gilpin, M. E., eds. Metapopulation Biology. Academic Press, San Diego, CA.

Heckenberger, M. J., A. Kuikuro, U. T. Kuikuro, J. C. Russell, M. Schmidt, C. Fausto, and B. Franchetto. 2003. Amazonia 1492: pristine forest or cultural parkland? Science 301: 1710-1714.

Hughes, R. and F. Flintan. 2001. Integrating Conservation and Development Experience: A Review and Bibliography of the ICDP Literature. International Institute for Environment and Development, London, UK.

Laurance, W. F. and W. F. Bierregaard, eds. 1997. Tropical Forest Fragmentation: Ecology, Management and Conservation of Fragmented Communities. Chicago University Press, Chicago, IL.

Levins, R. 1969. Some demographic and genetic consequences of environmental heterogeneity for biological control. Bulletin of the Entomological Society of America 15: 237-240.

MacArthur R. H. and Wilson E. O. 1967. The Theory of Island Biogeography. Princeton University Press, Pinceton, NJ.

Maranon, T. 1985. Diversidad floristica y heterogeneidad ambiental en una dehesa de Sierra Morena. Anales de Edafologia y Agrobiologia 44: 1183-1197.

Merchant, C., ed. 1993. Major Problems in American Environmental History. Houghton Miffin Co., Boston, MA.

McNeely, J. A. and S. J. Scherr. 2003. Ecoagriculture: Strategies to Feed the World and Save Wild Biodiversity. Island Press, Washington, D.C.

Moguel, P. and V. M. Toledo. 1999. Biodiversity conservation in traditional coffee systems in Mexico. Conservation Biology 13: 1-12.

Myers, N. 1988. Threatened biotas: "hotspots" in tropical forests. Environmentalist 8(3): 1-20.

Newark, W. D. 1995. Extinctions of mammal populations in Western North American national parks. Conservation Biology 9: 512-526.

Oates, J. F. 1999. Myth and Reality in the Rain Forest: How Conservation Strategies Are Failing in West Africa. University of California Press, Berkeley, CA.

Perfecto, I. and I. Armbrecht. 2003. The Coffee Agroecosystem in the Neotropics: Combining Ecological and Economic Goals. Pp 159-194 in J. Vandermeer, ed. Tropical Agroecosystems. CRC Press, Boca Raton.

Perfecto, I., R. Rice, R. Greenberg, and M. Van der Voolt. 1996. Shade coffee as refuge of biodiversity. BioScience 46:589-608.

Perfecto, I. and J. H. Vandermeer. 2002. Quality of agroecological matrix in a tropical montane landscape: ants in coffee plantations in Southern Mexico. Conservation Biology 16: 174-182.

Pimentel, D., U. Stachow, D.A. Takacs, H.W. Brubaker, A.R. Dumas, J.J. Meaney, J.A.S. O'Neil, D.E. Onsi, and D.B. Corzilius. 1992. Conserving biological diversity in agricultural/ forestry systems: most biological diversity exists in human-managed ecosystems. BioScience 42(5):354-362.

Pineda, F. D. and J. Montalvo. 1995. Dehesa System in the Western Mediterranean: Biological Diversity in Traditional Land Use Systems. Pp 107-122 in Halladay, P. and Gilmour, D. A., eds. Conserving Biodiversity Outside Protected Areas. The Role of Traditional Agro-ecosystems. IUCN, Gland.

Plieninger, T and C. Wilbrand. 2001. Land use, biodiversity conservation, and rural development in the dehesas of Cuatro Lugares, Spain. Agroforestry Systems 51: 23-34.

Redford, K. H. and J. G. Robinson. 1991. Park Size and the Conservation of Forest Mammals in Latin America. Pp 227-234 in M. A. Mares and D. J. Schmidly, eds. Latin America Mammology History, Biodiversity and Conservation. University of Oklahoma Press, Norman.

Roosevelt, A. C., M. L. Costa, C. L. Machado, M. Michab, N. Mercier, H. Valladas, J. feathers, W. Barnett, M. I. Silveira, A. Henderson, J. Silva, B. Chernoff, D. S. Reese, J. A. Holman, N. Toth, and K. Schick. 1996. Paleoindian cave dwellers in the Amazon: the people of the Americas. Science 272:373-384.

Schaefer, M. and J. Schauermann. 1990. The soil fauna of beech forests: comparison between a mull and a moder soil. Pedobiologia 34:299-314.

Simonian, L. 1995. Defending the Land of the Jaguar: A History of Conservation in Mexico. University of Texas Press, Austin.

Terborgh, J. 1999. Requiem for Nature. Island Press, Washington, D.C.

Torsvik, V., J. Goksoyr, F.L. Daae, R. Sorheim, J. Michalsen and K. Salte. 1994. Use of DNA Analysis to Determine the Diversity of Microbial Communities. Pp 39-48 in K. Ritz, J. Dighton and K.E. Giller, eds. Beyond the Biomass: Composition and Functional Analysis of Soil Microbial Communities, John Wiley and Sons, Chichester, U.K.

Vandermeer, J. H. and I. Perfecto. 1995. Breakfast of Biodiversity: The Truth about Rain Forest Destruction. Institute for Food and Development Policies, Oakland, CA.

Vandermeer, J. H. and Carvajal, R. 2001. Metapopulation dynamics and the quality of the landscape. American Naturalist 158:211-220.

Vandermeer, J. H. 2003a. Agricultural scientists are wrong about agriculture and conservation scientists are wrong about conservation. Endangered Species Update 20:53-62.

Vandermeer, J. H., ed. 2003b. Tropical Agroecosystems. CRC Press, Boca Raton, FL.

Vandermeer, J., M. van Noordwijk, J.M. Anderson, C. Ong and I. Perfecto. 1998. Global change and multi-species agroecosystems: concepts and issues. Agriculture, Ecosystems Environment 67:1-22.

Vargas Marquez, F. 1984. Parques Nacionales de Mexico y Reservas Equivalentes: Pasado, Present y Futuro. Instituto de Investigaciones Economicas, UNAM, Mexico City.

Western, D. and M. Pearl. 1989. Conservation for the 21st Century. Oxford University Press, New York.

Whittaker R. J. 1998. Island Biogeography: Ecology, Evolution, and Conservation. Oxford University Press, Oxford.

Wilcox B. A. and Murphy D. D. 1985. Conservation strategy: the effects of fragmentation on extinction. American Naturalist 125:879-87.

Wilkie, D., E. Shaw, F. Rotberg, G. Morelli, and P. Auzel. 2000. Roads, development and conservation in the Congo basin. Conservation Biology 14:1614-1622.

Wilshusen, P. R., S. R. Brechin, C. L. Fortwangler, and P. C. West. 2002. Reinventing a square wheel: critique of a resurgent "protection paradigm" in international biodiversity conservation. Society and Natural Resources 15:1740.

World Conservation Monitoring Center. 2000. Global Biodiversity: Earth's Living Resources in the 21st Century. World Conservation Press, Cambridge.

Ivette Perfecto

School of Natural Resources

and the Environment

University of Michigan

430 E. University

Ann Arbor. MI 48109-1115

[e-mail]

Ivette Perfecto received her Ph.D in Natural Resources from the University of Michigan in 1989. She is a professor in the School of Natural Resources and Environment at the University of Michigan. Her research interest involves biological diversity in tropical agroecosystems, focusing on the effects of agricultural intensification and its impact on biodiversity. Another aspect of her research relates to the ecological function of biodiversity in diverse tropical agroecosystems, in particular the role of biodiversity in pest regulation. Most of this research is conducted in Mesoamerica (Nicaragua and Mexico).