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Minimising the harm to biodiversity of producing more food globally Full text
2011
Phalan, Ben | Balmford, Andrew | Green, Rhys E. | Scharlemann, Jörn P.W.
Should farming and conservation policies aim broadly to separate land for nature and land for production (land sparing) or integrate production and conservation on the same land (wildlife-friendly farming)? Most studies that try to address this question suffer from flaws in sampling design, inappropriate metrics, and/or failure to measure biodiversity baselines. We discuss how these failings can be addressed, and what existing information tells us about the key debates on this topic. The evidence available suggests that trade-offs between biodiversity and yield are prevalent. While there are some wildlife-friendly farming systems that support high species richness, a large proportion of wild species cannot survive in even the most benign farming systems. To conserve those species, protection of wild lands will remain essential. Sustainable intensification could help to facilitate sparing of such lands, provided that as much attention is given to protecting habitats as to raising yields. We discuss the general circumstances under which yield increases can facilitate land sparing, recognising that policies and social safeguards will need to be context-specific. In some situations, bringing degraded lands into production could help reduce pressure on wild lands, but much more information is needed on the biodiversity implications of using degraded lands. We conclude that restricting human requirements for land globally will be important in limiting the impacts on biodiversity of increasing food production. To achieve this, society will need to integrate explicit conservation objectives into local, regional and international policies affecting the food system.
Show more [+] Less [-]The INTERREG-DEVAG project : a regional network for the development of agroecological cropping systems for horticultural crops in the Carribbean Full text
2011
Fernandes, Paula | Lavigne, Christian | Rhino, Béatrice | Langlais, Christian | Deberdt, Peninna | Diédhiou, Siré | Ratnadass, Alain | Jannoyer, Magalie | Malézieux, Eric | Filloux, Denis
In our Caribbean islands, increasing local food production and reducing the negative impacts of agricultural practices are major concerns, especially in view of the most recent food crisis and the rising costs of imported food products and agricultural inputs. In this context, horticultural crops are the main target of the social demand to get access to safe, healthy and environmentally friendly products. Furthermore, horticultural products are an important source of income for small farmers. But currently these crops are still requiring highly intensive chemical input application (fertilizers, pesticides) due to strong biotic constraints (bacteria, viruses, insects...) amplified by abiotic conditions (heat, humidity). It has become necessary to consider a radical change in production methods to move towards environmentally friendly systems and offering healthy products to producers and consumers, while valorizing biological resources already present in these fragile ecosystems though rich in biodiversity. The objectives of the DEVAG project are (i) to develop scientific databases to accelerate the development of agroecological and organic horticultural productions and (ii) to create a regional network dedicated to the development of agroecology for fruits and vegetables in the Caribbean. To do so, research activities focus on the development of agroecological methods to manage insects, diseases and weeds. These pests represent the main cause of loss of productivity and increase of pesticides use. Nevertheless, in order to build integrated cropping systems adoptable in our environments, research also encompass: (i) substitution of chemical fertilizers with local organic resources, (ii) selection of cultivars adapted to low-input systems, (iii) crop-livestock integration and (iv) characterization of socio-economic determinants of technical innovations. These research activities are conducted in permanent connection with farmers and agricultural development agents who will benefit directly by participating in field experiments and technical field schools. (Résumé d'auteur)
Show more [+] Less [-]GIS-based models for the development of sustainable aquaculture of native fish species in central Mexico: a catchment level approach for the protection of biodiversity. Full text
2011
Peredo-Alvarez, Victor M. | Ross, Lindsay G. | Telfer, Trevor C. | CONACyT, Mexico (Consejo Nacional de Ciencia y Tecnologia) (In English: National Council of Science and Technology, Mexico.) | School of Natural Sciences | Aquaculture
Over the last 3 decades, freshwater aquaculture has become one of the most important food industries. However the constant introduction of a reduced number of very successful species for aquaculture has been identified as one of the main activities related to the alarming decline of fish biodiversity worldwide. This issue has raised awareness amongst the scientific community, governmental authorities and the general public towards freshwater fish biodiversity. This new awareness has promoted the development of “green” markets and environmentally friendly strategies, aiming for a reliable production of protein sources. The development of native species aquaculture has been presented as a strong alternative for sustainable aquaculture and the protection of biodiversity. However, it seems clear that unplanned native species aquaculture developments can be as detrimental on local biodiversity as the introduction of exotic fish, if not more dangerous. Therefore, the advantages and disadvantages of native species aquaculture have to be clearly analysed before any aquaculture development. This study aimed to establish a philosophical background regarding the use of native fish species in aquaculture in contrast to the introduction of exotic species that may compete for a similar niche as food in local markets. The main ecological impacts that exotic fish species may have on natives, such as competition, predation, and hybridization were discussed. In addition, a well planned native species Aquaculture Strategy for the Protection of Biodiversity was produced, at catchment level, within a Geographic Information System (GIS). For the development of the native species aquaculture strategy in central Mexico, four species of Atherinids (Chirostoma estor, C. Jordani, C. promelas and Atherinella balsana) and two species of native Ictalurids (Ictalurus balsanus and Ictalurus dugesii) were included in this study. These six species are relatively new to aquaculture and they were selected on the basis of their importance in local fisheries and markets in their native basins of the Lerma-Santiago and Balsas rivers. Both of these basins are of great importance in central Mexico, not only because of their biodiversity but also because of their high human population densities and socio-economic status. The use of Geographic Information Systems was a fundamental factor in the development of the native species aquaculture strategy at catchment level, consisting of site suitability models (SSM) for each species in their corresponding native catchments. Overall, SSM identified 13,916 km2 and 11,178 km2 highly suitable for aquaculture of the studied Atherinids and Ictalurids respectively, based on Water, Soil and Terrain, Infrastructure and Risk sub-models. A set of predictive species distribution models (PSDM), which related ecological characteristics for each studied species with relevant environmental and topographic parameters into a GIS, were also produced. Such models were developed for the establishment of potential natural ranges of distribution for each species, as well as their potential to become exotic in new environments, as a potential for invasion model (PI). Based on a partial verification, both PSDM and PI models produced results that were satisfactorily consistent with the known distribution of each modelled species. The combination of SSM and PSDM produced an Aquaculture Strategy for the Protection of Biodiversity model (ASPB) which identified the most environmentally friendly suitable areas for aquaculture sites. In contrast, the combination of the SSM with PI models into an ASPB model identified the site suitability potential for non-native species that are genetically close to native ones, in an attempt to reduce the known impacts that exotic species have on local biodiversity. In this way the ASPB model identified 7,651 km2 suitable for aquaculture of I. balsanus in its native Balsas basin and 15,633 km¬2 suitable for aquaculture of the non-native I. dugesii. ASPB models were produced for all the studied species. The final results were used to produce a set of guidelines for the development of sustainable aquaculture of native species at catchment level that cover genetic and ecological implications, as well as a well planned decision making tool produced in a GIS.
Show more [+] Less [-]Enhancing agricultural productivity and rural incomes through sustainable use of natural resources in the Semi Arid Tropics Full text
2011
suhas p wani | girish chander | william d dar | yin dixin | zhong li
Enhancing agricultural productivity and rural incomes through sustainable use of natural resources in the Semi Arid Tropics Full text
2011
suhas p wani | girish chander | william d dar | yin dixin | zhong li
BACKGROUND: A participatory watershed management approach is one of the tested, sustainable and eco-friendly options to upgrade rain-fed agriculture to meet growing food demand along with additional multiple benefits in terms of improving livelihoods, addressing equity issues and biodiversity concerns.RESULTS: Watershed interventions at study sites in Thailand (Tad Fa and Wang Chai) and India (Kothapally) effectively reduced runoff and the associated soil loss. Such interventions at Xiaoxincun (China) and Wang Chai improved groundwater recharging and availability. Enhanced productive transpiration increased rainwater use efficiency for crop production by 13?29% at Xiaoxincun; 13?160% at Lucheba (China), 32?37% at Tad Fa and 23?46% at Wang Chai and by two to five times at Kothapally. Watershed interventions increased significantly the additional net returns from crop production as compared with the pre-watershed intervention period. Increased water availability opened up options for crop diversification with high-value crops, including increased forage production and boosted livestock-based livelihoods.CONCLUSION: In dryland tropics, integrated watershed management approach enabled farmers to diversify the systems along with increasing agricultural productivity through increased water availability, while conserving the natural resource base. Household incomes increased substantially, leading to improved living and building the resilience of the community and natural resources. Copyright © 2011 Society of Chemical Industry | Suhas P Wani et al., 'Enhancing agricultural productivity and rural incomes through sustainable use of natural resources in the Semi Arid Tropics', Journal of the Science of Food and Agriculture, vol. 92(5), pp.1054-1063, Wiley, 2011
Show more [+] Less [-]Enhancing agricultural productivity and rural incomes through sustainable use of natural resources in the Semi Arid Tropics Full text
2012
Wani, Suhas P | Dixin, Yin | Li, Zhong | Dar, William D. | Chander, Girish
BACKGROUND: A participatory watershed management approach is one of the tested, sustainable and eco‐friendly options to upgrade rain‐fed agriculture to meet growing food demand along with additional multiple benefits in terms of improving livelihoods, addressing equity issues and biodiversity concerns. RESULTS: Watershed interventions at study sites in Thailand (Tad Fa and Wang Chai) and India (Kothapally) effectively reduced runoff and the associated soil loss. Such interventions at Xiaoxincun (China) and Wang Chai improved groundwater recharging and availability. Enhanced productive transpiration increased rainwater use efficiency for crop production by 13–29% at Xiaoxincun; 13–160% at Lucheba (China), 32–37% at Tad Fa and 23–46% at Wang Chai and by two to five times at Kothapally. Watershed interventions increased significantly the additional net returns from crop production as compared with the pre‐watershed intervention period. Increased water availability opened up options for crop diversification with high‐value crops, including increased forage production and boosted livestock‐based livelihoods. CONCLUSION: In dryland tropics, integrated watershed management approach enabled farmers to diversify the systems along with increasing agricultural productivity through increased water availability, while conserving the natural resource base. Household incomes increased substantially, leading to improved living and building the resilience of the community and natural resources.
Show more [+] Less [-]Enhancing agricultural productivity and rural incomes through sustainable use of natural resources in the Semi Arid Tropics
Mitigating Greenhouse Gases in Agriculture Full text
2011
Muller, Adrian | Jawtusch, Julia | Gattinger, Andreas
Climate change has severe adverse effects on the livelihood of millions of the world’s poorest people. Increasing temperatures, water scarcity and droughts, flooding and storms affect food security. Thus, mitigation actions are needed to pave the way for a sustainable future for all. Currently, agriculture directly contributes about 10-15 percent to global greenhouse gas (GHG) emissions. Adding emissions from deforestation and land use change for animal feed production, this rises to about 30 percent. Scenarios predict a significant rise in agricultural emissions without effective mitigation actions. Given all the efforts undertaken in other sectors, agriculture would then become the single largest emitter within some decades, and without mitigation in agriculture, ambitious goals, such as keeping global warming below two degrees may become impossible to reach. The main agricultural emission sources are nitrous oxide from soils and methane from enteric fermentation in ruminants. In addition, conversion of native vegetation and grasslands to arable agriculture releases large amounts of CO2 from the vegetation and from soil organic matter. The main mitigation potential lies in soil carbon sequestration and preserving the existing soil carbon in arable soils. Nitrous oxide emissions can be reduced by reduced nitrogen application, but much still remains unclear about the effect different fertilizer types and management practices have on these emissions. Methane emissions from ruminants can only be reduced significantly by a reduction in animal numbers. Sequestration, finally, can be enhanced by conservative management practices, crop rotation with legumes (grass-clover) leys and application of organic fertilizers. An additional issue of importance are storage losses of food in developing and food wastage in developed countries (each about 30-40 percent of end products). Thus, there are basically five broad categories of mitigation actions in agriculture and its broader context: zz reducing direct and indirect emissions from agriculture; zz increasing carbon sequestration in agricultural soils; zz changing human dietary patterns towards more climate friendly food consumption, in particular less animal products; zz reducing storage losses and food wastage; zz the option of bioenergy needs to be mentioned, but depending on the type of bioenergy several negative side-effects may occur, including effects on food security, biodiversity and net GHG emissions. Although there are many difficulties in the details of mitigation actions in agriculture, a paradigm of climate friendly agriculture based on five principles can be derived from the knowledge about agricultural emissions and carbon sequestration: zz Climate friendly agriculture has to account for tradeoffs and choose system boundaries adequately; zz it has to account for synergies and adopt a systemic approach; zz aspects besides mitigation such as adaptation and food security are of crucial importance; zz it has to account for uncertainties and knowledge gaps, and zz the context beyond the agricultural sector has to be taken into account, in particular food consumption and waste patterns. Regarding policies to implement such a climate friendly agriculture, not much is yet around. In climate policy, agriculture only plays a minor role and negotiations proceed only very slowly on this topic. In agricultural policy climate change mitigation currently plays an insignificant role. In both contexts, some changes towards combined approaches can be expected over the next decade. Its 13 is essential that climate policy adequately captures the special characteristics of the agricultural sector. Policies with outcomes that endanger other aspects of agriculture such as food security or ecology have to be avoided. Agriculture delivers much more than options for mitigating greenhouse gas emissions and serving as a CO2 sink. We close this report with recommendations for the five most important goals to be realized in the context of mitigation and agriculture and proposals for concrete actions. First, soil organic carbon levels have to be preserved and, if possible, increased. Governments should include soil carbon sequestration in their mitigation and adaptation strategies and the climate funds should take a strong position on supporting such practices. Second, the implementation of closed nutrient cycles and optimal use of biomass has to be supported. Again, governments and funds should act on this. Policy instruments for nitrate regulation are a good starting point for this. As a third and most effective goal, we propose changes in food consumption and waste patterns. Without a switch to attitudes characterized by sufficiency, there is a danger that all attempts for mitigation remain futile. Finally, there are two goals for research, namely to develop improved knowledge on nitrous oxide dynamics, and on methods for assessment of multi-functional farming systems. Without this, adequate policy instruments for climate friendly agriculture and an optimal further development of it are not possible.
Show more [+] Less [-]What Can Organic Farming Deliver? Lessons Learnt From 20 Years of Organic Pioneering Projects in New Member States Full text
2011
Znaor, Darko
Summary: Avalon has been supporting organic farming in the New Member States since 1991. It has implemented numerous demonstration, research, education, policy making and awareness raising projects. Avalon has acquired a substantial legacy from its twenty years experience in inspiring, empowering and enabling organic movements in all New Member States. The present stage of development of the organic sector is quite different than the pioneering situation from twenty years ago. Today, the organic movement requires a different “language”, approach and advocacy tools. It is challenged to prove that it can create bridges and build alliances with other sustainable food and farming movements. Organic farming has become part of the mainstream and it ought to seek synergy with progressive businesses, promoters of the public good, policy makers and other actors. However, in doing this, organic farming should strive to retain its integrity and remain committed to its basic principles. This is often very challenging and sometimes nearly impossible to achieve. However, evidence from Avalon’s experience show that much can be done in this field. Avalon currently runs a network of nearly 200 members from over 30 countries. It is a wide platform of organisations and individuals recognising organic farming as a force that can bring a positive change to our food and farming systems. The organic farming concept and practice might not be the solution for all socio-economic and environmental problems that humankind faces today. But it is one of the “second-best” alternatives. A vast body of scientific evidence, as well as achievements from practice indicate that organic farming, being a multiple-objective activity, scores quite well on major sustainability parameters. It delivers public goods and services, while at the same time generating economic benefits. It is farming for people, planet and profit. By purchasing organic products consumers “vote” daily for a “multi-value bag” and sustainability. Like many others, Avalon’s projects in the New Member States also demonstrate and confirm that organic farming contributes to halting climate change and the loss of biodiversity; soil fertility building; food security; economic prosperity and cohesion of rural communities and the rural fabric. Avalon: serving the New Member States’ organic movement since 1991 Avalon is an international foundation, based in the Netherlands. Since 1991 Avalon has been serving the organic movement in the New Member States (and beyond). It has implemented numerous demonstration, research, education, policy making and organic farming awareness raising projects in all New Member States (and some twenty other countries). Avalon was in fact one of the very first Old Member State organisations that supported New Member States in paving the road to organic farming. It has provided technical, financial, policy and various other forms of support to the New Member States' ministries, universities, organic NGOs and other stakeholders. Its conference held in Castle Rudolec (Czech Republic) in 1993, gathering several ministers, vice-ministers and officials from the New Member States and international organisations was the first high-level organic farming conference ever held. The Grožnjan conference held in 1995 in Croatia was another important milestone for the organic movement. It gathered organic movement leaders from all New Member States (as well as from several other countries) and resulted in the Grožnjan Declaration. This was the first document in which major environmental and nature conservation organisations (IUCN, BirdLife International, WWF and Euronatur) jointly gave credit to organic farming for its environmental and biodiversity benefits. Since 2000, Avalon has implemented several multi-year agri-environment projects and was instrumental in introducing and designing these in the New Member States. Avalon’s projects have always been participatory and have been implemented in co-operation with counterparts from the New Member States including organic NGOs, ministries, universities, etc. Avalon currently runs a vast organic farming network. It is a wide platform of nearly 200 organic, environmental and nature protection NGOs, universities, research institutes, businesses, ministries and individuals from over 30 countries, who seek to unite their efforts in shaping an organic future. Avalon’s recent activities in the New Member States, among others, include three international conferences and a major biodiversity project. In 2009, Avalon held two international conferences in Bulgaria: (1) on organic agriculture and climate change; and (2) on organic agriculture, biodiversity and business. A large international conference on greening the EU Common Agricultural Policy was held in November 2010 in Slovenia. In Bulgaria, through its Bulgarian branch and together with the Ark Foundation, Avalon runs a multi-year project aimed at linking biodiversity, organic farming and eco-tourism in the Rhodopi Mountains – one of the hottest biodiversity spots in Europe. What can organic farming deliver? Organic farming can make a contribution towards solving numerous social, environmental, economic and agronomic problems. Projects implemented by Avalon and its partners indicate that organic farming can deliver numerous benefits for the environment, economy and society in the New Member States (and elsewhere). Elaborating on these in detail would go far beyond the scope of this paper. As details can be found in Avalon’s annual reports and other publications (www.avalon.nl) only basic information on some key issues will be provided here: • Biodiversity: Organic farming can make a substantial contribution to enriching biodiversity and protecting it from further degradation. This is because careful management, enhancing biodiversity and stimulating the biological processes of the farm ecosystem, are central to all organic farming concepts and practices. Numerous studies, as well as evidence from Avalon’s projects indicate that, in general, organic farming is more beneficial to biodiversity than non-organic management, notably intensive conventional agriculture. Organically farmed areas usually have a much higher abundance and diversity of micro-organisms, plants and animals. • Climate change: Organic farming contributes to the reduction greenhouse gas emissions because it reduces the consumption of fossil fuels (notably those used in fertiliser manufacturing), and reduces emissions of CO2, methane and nitrous oxide. It also reduces the vulnerability of soils to erosion, while at the same time increasing carbon stocks in the soil. Consequently, conversion to organic farming can be a viable way of reducing GHG emissions. Depending on the commodity produced, organic farming emits 6-60% less greenhouse gases than non-organic farming. However, when calculated per kg of product, in case of substantially lower yields, organic farming can result in a higher global warming potential. • Food security: food security is a complex issue stretching far beyond the mere question of the productivity potential of organic and other agricultural systems. Besides agriculture, food security also comprises various socio-economic and political aspects. In general, organic farming tends to result in lower yields, but as in conventional farming, this strongly depends on management skills and practices. Yields in organic farming tend to increase over time and contrary to most other systems, organic farming tends to ensure long-term production stability. • Profitability: Economic performance of organic farms tends to be similar to comparable conventional farms, but is strongly determined by the level of the premium price. However, when comparing the economic performance of conventional and organic farming, one has to take into account the negative externalities generated by conventional farming. These are substantial but the price we pay for food, in general does not reflect the environmental and social costs associated with its production, transport, processing, storage and trade.Studies from the EU Member States and Candidate Countries show that when external costs are internalised, the comparison between the economic performance of conventional and organic farming turns out to be quite favourable for organic. Lessons learnt from implementing organic farming projects in New Member States Organic farming is a multi-objective concept and its environmental and socio-economic benefits go far beyond questions about its performance on single criteria (e.g. yields obtained, contribution to climate or biodiversity protection, etc). However, the key challenge, particularly today, is how to communicate the organic concept so that it can successfully be adopted and embraced by society. The present stage of development of the organic sector is quite different than the pioneering situation from twenty years ago. Today, the organic movement requires a different “language”, approach and advocacy tools. After twenty years' experience in advocating and developing organic farming in the New Member States (and many other countries) Avalon has learned a number of lessons that can be useful for the European organic movement as a whole. In order to be better accepted organic farming should be developed through “shared ownership” with wider societal platforms. Creating bridges and building alliances with other sustainable food and farming movements are essential for the wider adoption and spread of organic ideas. Organic farming has become part of the mainstream and it ought to seek synergies with progressive businesses, public good promoters, policy makers and other actors. However, in doing this, organic farming should strive to retain its integrity and remain committed to its basic principles. This is often very delicate and sometimes nearly impossible to achieve – but it is a challenge and imperative of our age. In the context of the EU New Member States potential alliances might include linkage with slow-food-like movements, environmental and nature conservation organisations, natural medicine and alternative energy advocates, certain spiritual/church movements, etc. Some of these might prefer other farming methods over organic practices. We have to realise that these can also be very beneficial, such as pastoral or traditional farming. In fact, in many marginal European regions traditional farming practised by small-scale, (semi-) subsistence farmers is the only biodiversity-friendly alternative to land abandonment. In most cases these practices fully or largely comply with the principles of organic farming. However, since such production is not predominantly market-oriented it is not certified as organic. In contrast to twenty years ago when organic development was mostly initiated by pioneering organic farmers and a handful of organic NGOs, a great deal of responsibility for the further development of organic farming today rests on policy makers. In order to catalyse the further development of the organic food and farming sector, policy makers should put into place a set of regulatory, economic and informative policy instruments favouring the development of organic farming and discouraging environmentally and socially damaging practices. In the EU, organic farming has to play a role in a wider agricultural policy context through agri-environment programmes and the post 2013 CAP greening initiatives. Besides policy makers, business is another important driver of change today. It moves fast as soon as it identifies market opportunities and sniffs the track of money. Organic market & chain development can be much enhanced if the organic sector properly teams up with business. By buying organic food and eating where organic food is served, consumers can also be a powerful driving force for the further development of organic farming. When purchasing organic food, consumers buy products that provide a range of social and environmental benefits, score high on animal welfare and often tend to have a higher nutritional value per weight unit. In short – by buying organic food consumers daily cast their vote for sustainability. However, many European consumers find the organic farming message too difficult to grasp and to “digest”. Unfortunately, we live in an “SMS society” in which holistic organic – for many a complicated concept – is difficult to understand. Having this in mind, there is an inevitable need - for the sake of attracting more consumers – to keep the “great” organic message short and simple. This is quite challenging, notably for organic pioneers. The valuation (“monetarisation”) of ecosystem services and environmental costs generated by farming and farm-upstream sectors is a newly emerging concept that seems to be a promising tool particularly for influencing policy changes. Emerging assessments from the EU and Candidate Countries suggest that hidden costs (public expenditure and environmental costs) associated with food and farming are immense. Making policy makers and the public at large aware of these costs and of potential savings by practising organic farming can foster the wider adoption of organic farming. However, it is important to keep in mind that there is some concern as to what a widespread adoption of organic farming would bring to society as a whole. The costs and benefits of this development and the associated trade-offs are largely unknown and have hardly been explored. Sophisticated assessments, computer models, statistics, facts and figures can help to cast more light on environmental and socio-economic consequences of large-scale conversion to organic farming. However they alone are not sufficient to trigger a change. Statistics never move people – but partnership and passion does. Avalon hopes to continue playing an inspiring, empowering and catalytic role and to serve the organic movement for many years to come.
Show more [+] Less [-]Organic farms as refuges for small mammal biodiversity in agro ecosystems Full text
2011
Jensen, Thomas Secher | Hansen, Tine Sussi | Olsen, Kent
Habitat fragmentation, the process by which relatively continuous habitats is broken into smaller pieces, occurs in natural systems but is to a high degree also human-induced through landscape use. Fragmentation of the landscape produces a series of habitat patches surrounded by a matrix of different habitats and land use regimes. The major landscape consequences of fragmentation are loss of habitat, reduction in habitat patch size, and increasing isolation of habitat patches. In general, population performance declines in response to habitat loss but size of remaining area and isolation effects is known also to influence the population trend. Small mammals are well suited for examination of population responses to habitat fragmentation as they have modest spatial requirements and short generation times. In theory, organic farms could play an important role in the agricultural landscape as refuges for some small mammal species, as the lack of pesticide and fertiliser treatment, less weed control, more diversified crop structure and a general environmental friendly attitude, form a basis for habitats that provide cover and food for small mammals, and thus for larger predators of these species. Furthermore, density and area of small biotopes could be expected to be higher in the organic farms, thus leading to a decreased distance between optimal habitats. This study compares species diversity and abundance of small mammals in conventional farms and intensively and extensively grown organic farms. In a wide range of different fields in conventional and organic farms, the diversity and density of small mammals were investigated by live-trapping sessions, comprising trap lines with 15 meters between each trap. We studied the responses of populations (belonging to 11 species of small mammals) to habitat patches of different size and different surrounding management strategies (ecological and conventional farming). We found a general correlation between the number of small mammal individuals and small biotope size. This correlation applies in autumn as well as in spring. There is only a weak tendency for more small mammals in small biotopes within organic farms compared within conventional farms. The number of small mammal species stabilises at small biotope sizes around 1000 square meters. The value of organic farms in respect to small mammal biodiversity depends mainly upon the number and area of small biotopes, and only to a minor degree upon the treatments of the fields.
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