**1. Introduction**

314 Ecosystems Biodiversity

Wikelski, M.; Foufopoulos, J.; Vargas, H. & Snell, H. (2004). Galápagos Birds and Diseases:

Wikelsky, M.; Romero, L.M. & Snell., H.L. (2001). Marine iguanas oiled in the Galapagos. *Science* Vol. 292, No. 5516, (April 2001), pp. 437-438, ISSN 0036-8075 Wikelsky, M.; Wong, V.; Chevalier, B.; Rattenborg, N. & Snell, H.L. (2002). Marine iguanas

(January 2004), Art. 5, ISSN: 1708-3087, Available from

http://www.ecologyandsociety.org/vol9/iss1/art5/

ISSN 0090-3558

Invasive Pathogens as Threats for Island Species. *Ecology and Society* Vol. 9, No.1

die from trace oil pollution. *Nature* Vol. 417, No. 6889, (June 2002), pp. 607-608,

We are in the midst of the sixth global mass extinction event (McNeely & Scherr, 2002; Thomas et al., 2004). Around the globe, biological communities that took millions of years to develop—including tropical rain forests, coral reefs, old-growth forests, prairies and coastal wetlands—have been devastated as a result of human actions. Biologists predict that tens of thousands of species and millions of unique populations will go extinct in the coming decades (Brown & Laband, 2006; Millennium Ecosystem Assessment, 2005a). If the current predictions are correct, the rates of environmental changes may outpace the capacities of organisms to adapt to the changes.

There are seven major threats to biodiversity: habitat destruction; habitat fragmentation; habitat degradation (including pollution); global climate change; the overexploitation of species for human use; the invasion of exotic species; and the increased spread of disease. Most threatened species and ecosystems face at least two or more of these threats, which can interact synergistically to speed the way to extinction and hinder efforts at protecting biodiversity (Burgman et al., 2007; Millennium Ecosystem Assessment, 2005b). All seven threats are the result of an expanding human population's ever increasing use of the world's natural resources (Primack, 2008).

Agroecosystems include a large proportion of the world's biodiversity (Pimentel et al., 1992). Over the past two decades, research has demonstrated the value of agricultural biodiversity in all its forms, including crop and livestock genetic diversity, and associated species important for production, for example, pollinators, soil microorganisms, beneficial insects, and predators of pests and wild species that occur in agricultural landscapes (Uphoff et al., 2006). Some species are almost completely dependent on agricultural habitats for survival, e.g. Great Bustard *Otis tarda*, Grey Partridge *Perdix perdix* or the Black-tailed Godwit *Limosa limosa* (Kleijn et al., 2006).

Since the 1960's both industrial agriculture in developed countries and the original green revolution in developing countries have depended on improved seeds, chemical fertilizers, pesticides and irrigation. This production model involved a small number of crops, generally in monoculture (to increase efficiency in use of inputs and mechanization), increased pesticide and fertilizer use and short crop-rotations (Benton et al., 2003). Wild flora and fauna were considered direct competitors for resources or harvested products,

Biodiversity Drifts in Agricultural Landscapes 317

fourths of a million new people each year will suffer from chronic effects of exposure. For all these reasons, new solutions are necessary for producing more food and fibre, protecting the resource base upon which agriculture depends and promoting social well-being

In Europe, the Common Agricultural Policy (CAP), born 50 years ago, began by subsidizing production of basic foodstuffs in the interests of self-sufficiency, after the difficult period of the war. Currently, CAP, give farmers an important role in improving quality, preserving biodiversity and traditional landscapes and keeping rural economies alive. Furthermore, more informed consumers are entitled to food that is safe and of high quality; this induced the creation of regulations defining organic foods and also what can be considered an organic farm. More extensive systems, such as organic farming, aim to mitigate the negative effects of modern agriculture and enhance biodiversity (Krebs et al., 1999; Reganold et al., 2001; Tybirk et al., 2004). Agri-environmental schemes (AES) were introduced into the European Common Agricultural Policy (CAP) in the early 1990s to reduce biodiversity loss in agricultural landscapes and mitigate other harmful effects of modern agriculture. AES are considered the most important policy instruments for protecting biodiversity in agricultural landscapes (European Environment Agency report, 2004) as they provide financial incentives to farmers for adopting environmentally friendly practices mostly at the field

**2. Agriculture intensification and Agri-environmental schemes** 

scale (i.e., reduction in pesticide and fertiliser applications or delaying harvesting).

With the increasing number of organic farms, several studies and meta-analyses have been conducted, with the sole purpose of finding a correspondence between the decline in biodiversity and the AI in conventional versus organic farms. Nevertheless, sometimes these studies are inconclusive, contradictory and sometimes positive results are found. Recent European-wide studies have questioned the effectiveness of AES for biodiversity conservation. Over half the studies showed significant positive effects of AES on the diversity or abundance of target groups such as plants, birds or arthropods, but the remaining studies showed non-significant or even negative effects (Kleijn et al., 2006; Kleijn & Sutherland, 2003). Usually the positive effects of organic farming relative to conventional agriculture are in terms of botanic diversity (Bengtsson et al., 2005; Hald, 1999; Hyvönen et al., 2003) whereas arthropods appear to respond ambiguously to organic cropping (reviewed in Hole et al., 2005). There are also other studies on other measures of agriculture intensification, for example, grazing intensification, extensive vs. intensive farming, etc. One, however, should not expect immediate results from the introduction of AES. For example, Ameixa & Kindlman (2008) did not find any relation between agricultural practices and the diversity and abundance of carabids in several agricultural fields, which was probably because the species that live in agricultural fields have already undergone some kind of selection and are for this reason adapted to the constant changes. For example, in many parts of Europe, agricultural landscapes are well over 2000 years old (Groppali, 1993; Williamson, 1986), so organisms must be adapted to this environment. Thus, studies that compare organic vs. conventional fields should not aim to see an immediate change in biodiversity patterns in agricultural landscapes after years of intense land use, but find other

Another expectation is that even if AES are applied and therefore agriculture becomes less intensive, diversity will increase only until a certain maximum in agricultural fields above

(Millennium Ecosystem Assessment, 2005b).

methods to access this problem.

while water was diverted from wetlands and natural habitats for irrigation (Uphoff et al., 2006), and intensification has reduced the suitability of agricultural fields for a wide range of organisms (Benton et al., 2003). The cultivation of annual crops has expanded at the cost of non-crop habitats such as extensive grasslands, fallow, hedges and field margins (Benton et al., 2003; Tilman et al., 2001b). Non-crop habitats provide dispersal corridors for wildlife and habitat islands required by many species as refuges and feeding areas (Öckinger & Smith, 2007; Stoate et al., 2001). Non-crop habitats can also act as biodiversity reservoirs for natural enemies, which can potentially improve natural pest control in agricultural landscapes (Ives et al., 2000; Wilby & Thomas, 2002), however, they can also act as reservoirs for pest species, which can colonize the crops (van Emden, 1965).

The expansion of agricultural intensification (AI) is often considered to be an important factor that has contributed to a rapid decline in biodiversity in agroecosystems (Benton et al., 2003; Mattison & Norris, 2005) and negatively affected the production of ecosystem services, e.g., maintenance of fertile soils, biotic regulation, nutrient recycling, assimilation of wastes, sequestration of carbon dioxide, and maintenance of genetic information (Benton et al., 2003; Chamberlain et al., 2000; Hooper et al., 2005; Robinson & Sutherland, 2002; Tilman et al., 2002). Wilcove et al. (1998) estimated that 38% of the endangered species in the United States are negatively affected by agricultural practices. Changes in landscape composition and intensive management practices are believed to be the main factors causing this decline. Also many species of raptor have been negatively affected by prey declines, probably associated with AI (Tucker & Heath, 1994). Furthermore, the potential of biodiversity for providing ecological resilience, i.e., the capacity to recover from disruption of functions, and the mitigation of risks caused by disturbance (Holling, 1996; Swift, 2004) is poorly documented. A better knowledge of which goods and services are provided by agroecosystems is urgently needed since we live on the brink of no return.

At the present time, 10% of the global land area is under intensive agricultural use, 17% is under extensive use associated with the use of far fewer artificial inputs, and 40% is grazed by domestic livestock (Mooney et al., 2005; Wood et al., 2000). The world's population of 6.3 billion people is projected to grow to 7.2 billion by the year 2015, 8.3 billion by 2030 and to 9.3 billion by 2050 (FAO, 2003). By 2050, food production must double to meet human needs. In order to meet this increasing demand for food and fibre, production systems are expected to become increasingly dependent on synthetic inputs of fertilizers and pesticides (Clay, 2004). Since the world's population will continue to increase, we will increase agricultural output by 30–50% over the next 30 years; thus, the need to protect biodiversity will compete directly against the need for new agricultural land (Tilman et al., 2001a).

Not only biodiversity is at risk, lately there has been an increase in public awareness of the possible effects of agro-chemicals. Many studies document increased risk of cancer among children and adults associated with exposure to an array of pesticides (Alavanja et al., 2007; Dich et al., 1997; Zahm & Ward, 1998). Sometimes the dangers are ignored by the responsible entities, for example, the fungicide vinclozolin, which is widely used in vineyards, was registered for use in 2000, despite laboratory tests indicating that it causes testicular cancer and disrupts normal androgen activity in laboratory animals (U.S. Environmental Protection Agency, 2000). Pesticide poisoning is also a daily hazard for the majority of the world's rural population (Dinham & Malik, 2003). The World Health Organization (WHO, 1990) has indicated that 20,000 women, men and children die of accidental pesticide poisoning each year, three million are poisoned, and nearly three

while water was diverted from wetlands and natural habitats for irrigation (Uphoff et al., 2006), and intensification has reduced the suitability of agricultural fields for a wide range of organisms (Benton et al., 2003). The cultivation of annual crops has expanded at the cost of non-crop habitats such as extensive grasslands, fallow, hedges and field margins (Benton et al., 2003; Tilman et al., 2001b). Non-crop habitats provide dispersal corridors for wildlife and habitat islands required by many species as refuges and feeding areas (Öckinger & Smith, 2007; Stoate et al., 2001). Non-crop habitats can also act as biodiversity reservoirs for natural enemies, which can potentially improve natural pest control in agricultural landscapes (Ives et al., 2000; Wilby & Thomas, 2002), however, they can also act as reservoirs for pest species,

The expansion of agricultural intensification (AI) is often considered to be an important factor that has contributed to a rapid decline in biodiversity in agroecosystems (Benton et al., 2003; Mattison & Norris, 2005) and negatively affected the production of ecosystem services, e.g., maintenance of fertile soils, biotic regulation, nutrient recycling, assimilation of wastes, sequestration of carbon dioxide, and maintenance of genetic information (Benton et al., 2003; Chamberlain et al., 2000; Hooper et al., 2005; Robinson & Sutherland, 2002; Tilman et al., 2002). Wilcove et al. (1998) estimated that 38% of the endangered species in the United States are negatively affected by agricultural practices. Changes in landscape composition and intensive management practices are believed to be the main factors causing this decline. Also many species of raptor have been negatively affected by prey declines, probably associated with AI (Tucker & Heath, 1994). Furthermore, the potential of biodiversity for providing ecological resilience, i.e., the capacity to recover from disruption of functions, and the mitigation of risks caused by disturbance (Holling, 1996; Swift, 2004) is poorly documented. A better knowledge of which goods and services are provided by

At the present time, 10% of the global land area is under intensive agricultural use, 17% is under extensive use associated with the use of far fewer artificial inputs, and 40% is grazed by domestic livestock (Mooney et al., 2005; Wood et al., 2000). The world's population of 6.3 billion people is projected to grow to 7.2 billion by the year 2015, 8.3 billion by 2030 and to 9.3 billion by 2050 (FAO, 2003). By 2050, food production must double to meet human needs. In order to meet this increasing demand for food and fibre, production systems are expected to become increasingly dependent on synthetic inputs of fertilizers and pesticides (Clay, 2004). Since the world's population will continue to increase, we will increase agricultural output by 30–50% over the next 30 years; thus, the need to protect biodiversity will compete directly against the need for new agricultural land (Tilman et al., 2001a). Not only biodiversity is at risk, lately there has been an increase in public awareness of the possible effects of agro-chemicals. Many studies document increased risk of cancer among children and adults associated with exposure to an array of pesticides (Alavanja et al., 2007; Dich et al., 1997; Zahm & Ward, 1998). Sometimes the dangers are ignored by the responsible entities, for example, the fungicide vinclozolin, which is widely used in vineyards, was registered for use in 2000, despite laboratory tests indicating that it causes testicular cancer and disrupts normal androgen activity in laboratory animals (U.S. Environmental Protection Agency, 2000). Pesticide poisoning is also a daily hazard for the majority of the world's rural population (Dinham & Malik, 2003). The World Health Organization (WHO, 1990) has indicated that 20,000 women, men and children die of accidental pesticide poisoning each year, three million are poisoned, and nearly three

agroecosystems is urgently needed since we live on the brink of no return.

which can colonize the crops (van Emden, 1965).

fourths of a million new people each year will suffer from chronic effects of exposure. For all these reasons, new solutions are necessary for producing more food and fibre, protecting the resource base upon which agriculture depends and promoting social well-being (Millennium Ecosystem Assessment, 2005b).
