The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Teja Tscharntke - One of the best experts on this subject based on the ideXlab platform.
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winners and losers of national and global efforts to reconcile Agricultural Intensification and biodiversity conservation
Global Change Biology, 2018Co-Authors: Christoph Scherber, Lukas Egli, Carsten Meyer, Holger Kreft, Teja TscharntkeAbstract:Closing yield gaps within existing croplands, and thereby avoiding further habitat conversions, is a prominently and controversially discussed strategy to meet the rising demand for Agricultural products, while minimizing biodiversity impacts. The Agricultural Intensification associated with such a strategy poses additional threats to biodiversity within Agricultural landscapes. The uneven spatial distribution of both yield gaps and biodiversity provides opportunities for reconciling Agricultural Intensification and biodiversity conservation through spatially optimized Intensification. Here, we integrate distribution and habitat information for almost 20,000 vertebrate species with land-cover and land-use datasets. We estimate that projected Agricultural Intensification between 2000 and 2040 would reduce the global biodiversity value of Agricultural lands by 11%, relative to 2000. Contrasting these projections with spatial land-use optimization scenarios reveals that 88% of projected biodiversity loss could be avoided through globally coordinated land-use planning, implying huge efficiency gains through international cooperation. However, global-scale optimization also implies a highly uneven distribution of costs and benefits, resulting in distinct "winners and losers" in terms of national economic development, food security, food sovereignty or conservation. Given conflicting national interests and lacking effective governance mechanisms to guarantee equitable compensation of losers, multinational land-use optimization seems politically unlikely. In turn, 61% of projected biodiversity loss could be avoided through nationally focused optimization, and 33% through optimization within just 10 countries. Targeted efforts to improve the capacity for integrated land-use planning for sustainable Intensification especially in these countries, including the strengthening of institutions that can arbitrate subnational land-use conflicts, may offer an effective, yet politically feasible, avenue to better reconcile future trade-offs between agriculture and conservation. The efficiency gains of optimization remained robust when assuming that yields could only be increased to 80% of their potential. Our results highlight the need to better integrate real-world governance, political and economic challenges into sustainable development and global change mitigation research.
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global food security biodiversity conservation and the future of Agricultural Intensification
Biological Conservation, 2012Co-Authors: Teja Tscharntke, Yann Clough, Thomas C Wanger, Louise E Jackson, Iris Motzke, Ivette Perfecto, John Vandermeer, Anthony M WhitbreadAbstract:Abstract Under the current scenario of rapid human population increase, achieving efficient and productive Agricultural land use while conserving biodiversity is a global challenge. There is an ongoing debate whether land for nature and for production should be segregated (land sparing) or integrated on the same land (land sharing, wildlife-friendly farming). While recent studies argue for Agricultural Intensification in a land sparing approach, we suggest here that it fails to account for real-world complexity. We argue that agriculture practiced under smallholder farmer-dominated landscapes and not large-scale farming, is currently the backbone of global food security in the developing world. Furthermore, contemporary food usage is inefficient with one third wasted and a further third used inefficiently to feed livestock and that conventional Intensification causes often overlooked environmental costs. A major argument for wildlife friendly farming and agroecological Intensification is that crucial ecosystem services are provided by “planned” and “associated” biodiversity, whereas the land sparing concept implies that biodiversity in agroecosystems is functionally negligible. However, loss of biological control can result in dramatic increases of pest densities, pollinator services affect a third of global human food supply, and inappropriate Agricultural management can lead to environmental degradation. Hence, the true value of functional biodiversity on the farm is often inadequately acknowledged or understood, while conventional Intensification tends to disrupt beneficial functions of biodiversity. In conclusion, linking Agricultural Intensification with biodiversity conservation and hunger reduction requires well-informed regional and targeted solutions, something which the land sparing vs sharing debate has failed to achieve so far.
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Agricultural Intensification and cereal aphid parasitoid hyperparasitoid food webs network complexity temporal variability and parasitism rates
Oecologia, 2012Co-Authors: Vesna Gagic, Carsten Thies, Christoph Scherber, Sebastian Hanke, željko Tomanovic, Teja TscharntkeAbstract:Agricultural Intensification (AI) is currently a major driver of biodiversity loss and related ecosystem functioning decline. However, spatio-temporal changes in community structure induced by AI, and their relation to ecosystem functioning, remain largely unexplored. Here, we analysed 16 quantitative cereal aphid-parasitoid and parasitoid-hyperparasitoid food webs, replicated four times during the season, under contrasting AI regimes (organic farming in complex landscapes vs. conventional farming in simple landscapes). High AI increased food web complexity but also temporal variability in aphid-parasitoid food webs and in the dominant parasitoid species identity. Enhanced complexity and variability appeared to be controlled bottom-up by changes in aphid dominance structure and evenness. Contrary to the common expectations of positive biodiversity-ecosystem functioning relationships, community complexity (food-web complexity, species richness and evenness) was negatively related to primary parasitism rates. However, this relationship was positive for secondary parasitoids. Despite differences in community structures among different trophic levels, ecosystem services (parasitism rates) and disservices (aphid abundances and hyperparasitism rates) were always higher in fields with low AI. Hence, community structure and ecosystem functioning appear to be differently influenced by AI, and change differently over time and among trophic levels. In conclusion, intensified agriculture can support diverse albeit highly variable parasitoid-host communities, but ecosystem functioning might not be easy to predict from observed changes in community structure and composition.
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persistent negative effects of pesticides on biodiversity and biological control potential on european farmland
Basic and Applied Ecology, 2010Co-Authors: Flavia Geiger, Piotr Ceryngier, Mark Emmerson, Manuel B Morales, Frank Berendse, Jaan Liira, Jan Bengtsson, Teja Tscharntke, Wolfgang W Weisser, Camilla WinqvistAbstract:During the last 50 years, Agricultural Intensification has caused many wild plant and animal species to go extinct regionally or nationally and has profoundly changed the functioning of agro-ecosystems. Agricultural Intensification has many components, such as loss of landscape elements, enlarged farm and field sizes and larger inputs of fertilizer and pesticides. However, very little is known about the relative contribution of these variables to the large-scale negative effects on biodiversity. In this study, we disentangled the impacts of various components of Agricultural Intensification on species diversity of wild plants, carabids and ground-nesting farmland birds and on the biological control of aphids. In a Europe-wide study in eight West and East European countries, we found important negative effects of Agricultural Intensification on wild plant, carabid and bird species diversity and on the potential for biological pest control, as estimated from the number of aphids taken by predators. Of the 13 components of Intensification we measured, use of insecticides and fungicides had consistent negative effects on biodiversity. Insecticides also reduced the biological control potential. Organic farming and other agri-environment schemes aiming to mitigate the negative
Marc Belisle - One of the best experts on this subject based on the ideXlab platform.
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seasonal patterns in tree swallow prey diptera abundance are affected by Agricultural Intensification
Ecological Applications, 2013Co-Authors: Sebastien Rioux Paquette, Dany Garant, Fanie Pelletier, Marc BelisleAbstract:In many parts of the world, farmland bird species are declining at faster rates than other birds. For aerial insectivores, this decline has been related to a parallel reduction in the abundance of their invertebrate prey in Agricultural landscapes. While the effects of Agricultural Intensification (AI) on arthropod communities at the landscape level have been substantially studied in recent years, seasonal variation in these impacts has not been investigated. To assess the contention that intensive cultures negatively impact food resources for aerial insectivorous birds, we analyzed the spatiotemporal distribution patterns of Diptera, the main food resource for breeding Tree Swallows (Tachycineta bicolor), across a gradient of AI in southeastern Quebec, Canada. Linear mixed models computed from a data set of 5000 samples comprising >150 000 dipterans collected over three years (2006–2008) suggest that both Diptera abundance and biomass varied greatly during swallow breeding season, following a quadratic c...
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breeding success of tree swallows along a gradient of Agricultural Intensification
Ecological Applications, 2008Co-Authors: Arnaud Ghilain, Marc BelisleAbstract:The Intensification of Agricultural practices has been identified as the main cause of population decline in farmland birds since the 1960s in both Europe and North America. Although the links between species richness or abundance and various components of Agricultural Intensification are well established, the mechanisms underlying these trends have rarely been addressed along a gradient of Intensification or have been quantified at only one spatial scale. Here we quantified the influence of landscape structure on the nest box occupancy and breeding success of Tree Swallows (Tachycineta bicolor) at seven spatial scales (1, 2, 3, 4, 5, 10, and 20 km radii) over a 10200-km2 gradient of Agricultural Intensification in southern Quebec, Canada. A network of 400 nest boxes distributed among 40 farms was visited every two days over three breeding seasons, 2004–2006. Nest box occupancy decreased with the proportion of intensive cultures (maize, cereals, and soybeans) in the landscape, especially when manure heaps and tanks were abundant, and was also determined by local variables (i.e., nest box clearance, interspecific competition) and by previous-year fledging success. Clutch size decreased as the breeding season progressed and with the proportion of intensive cultures in the landscape, with no consistent variation across spatial scales. Hatching success was not related to any landscape variables but increased with clutch size. Both the number of fledglings and fledging probability increased with the proportion of extensive cultures (hayfields, pastures, and fallows). These effects increased with spatial scale and reached a plateau at the 5 km radius: the maximum distance from the nest reached by foraging Tree Swallows. Our results can likely be attributed to lower food availability in intensive cultures compared to extensive ones. This study suggests that several components of breeding that impact on population structure and dynamics of insectivorous birds will be negatively affected by Agricultural Intensification.
Louise E Jackson - One of the best experts on this subject based on the ideXlab platform.
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global food security biodiversity conservation and the future of Agricultural Intensification
Biological Conservation, 2012Co-Authors: Teja Tscharntke, Yann Clough, Thomas C Wanger, Louise E Jackson, Iris Motzke, Ivette Perfecto, John Vandermeer, Anthony M WhitbreadAbstract:Abstract Under the current scenario of rapid human population increase, achieving efficient and productive Agricultural land use while conserving biodiversity is a global challenge. There is an ongoing debate whether land for nature and for production should be segregated (land sparing) or integrated on the same land (land sharing, wildlife-friendly farming). While recent studies argue for Agricultural Intensification in a land sparing approach, we suggest here that it fails to account for real-world complexity. We argue that agriculture practiced under smallholder farmer-dominated landscapes and not large-scale farming, is currently the backbone of global food security in the developing world. Furthermore, contemporary food usage is inefficient with one third wasted and a further third used inefficiently to feed livestock and that conventional Intensification causes often overlooked environmental costs. A major argument for wildlife friendly farming and agroecological Intensification is that crucial ecosystem services are provided by “planned” and “associated” biodiversity, whereas the land sparing concept implies that biodiversity in agroecosystems is functionally negligible. However, loss of biological control can result in dramatic increases of pest densities, pollinator services affect a third of global human food supply, and inappropriate Agricultural management can lead to environmental degradation. Hence, the true value of functional biodiversity on the farm is often inadequately acknowledged or understood, while conventional Intensification tends to disrupt beneficial functions of biodiversity. In conclusion, linking Agricultural Intensification with biodiversity conservation and hunger reduction requires well-informed regional and targeted solutions, something which the land sparing vs sharing debate has failed to achieve so far.
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Biodiversity is associated with indicators of soil ecosystem functions over a landscape gradient of Agricultural Intensification
Landscape Ecology, 2010Co-Authors: Steven W. Culman, Anna Young-mathews, Allan D. Hollander, Howard Ferris, Sara Sánchez-moreno, Anthony T. O’geen, Louise E JacksonAbstract:Agricultural Intensification has led to dramatic losses in biodiversity over the past several decades. Many studies have shown the effects of Intensification on vegetation or soil communities at field or local scales. However, the functional significance of biodiversity may only appear at larger spatial and temporal scales, due to exchanges among local ecosystems throughout a landscape. To examine how patterns of biodiversity loss are reflected at larger spatial scales, plant and soil biodiversity and associated indicators of ecosystem functions were assessed in riparian areas over a 150 km^2 Agricultural landscape in the Sacramento Valley of California. Publicly-available GIS data were first used to classify and select sites over the range of soils, topography and plant community types. Representative sites from the landscape were sampled for soil physiochemical properties, as well as microbial, nematode, and plant communities. Higher Agricultural Intensification, based on field and landscape indices, was negatively correlated with richness and diversity of plant and soil taxa, and was related to indicators of ecosystem functions, such as increased soil nitrate and phosphorus loading, decreased riparian health ratings, and lower soil carbon, soil microbial biomass and soil food web structure. Both field- and landscape-scale factors played important roles in the measured losses. The study area was composed of a wide array of soils, vegetation, and land management, indicating that the observed trends transcended site-specific conditions.
Michael H. Beare - One of the best experts on this subject based on the ideXlab platform.
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Agricultural Intensification, soil biodiversity and agroecosystem function
Applied Soil Ecology, 1997Co-Authors: Ken E. Giller, Patrick Lavelle, Michael H. Beare, A.-m.n. Izac, M J SwiftAbstract:Abstract Soil is the habitat of plant roots and of a diverse array of organisms—bacteria, fungi, protozoa and invertebrate animals —which contribute to the maintenance and productivity of agroecosystems. As Intensification occurs, the regulation of functions through soil biodiversity is progressively replaced by regulation through chemical and mechanical inputs. However, the causal relationships between (l) composition, diversity and abundance of soil organisms and (2) sustained soil fertility are unclear. Furthermore, in tropical Agricultural systems undergoing Intensification, large numbers of farmers have limited access to inputs, and therefore the maintenance and enhancement of soil biodiversity may be particularly relevant to such farmers. In this paper we propose a number of hypotheses which could be tested to explore the relationships between Agricultural Intensification, biodiversity in tropical soils and ecosystem functions. We also provide a conceptual framework within which such hypotheses can be tested.
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Agricultural Intensification soil biodiversity and agroecosystem function in the tropics the role of decomposer biota
Applied Soil Ecology, 1997Co-Authors: Michael H. Beare, Vikram M Reddy, G Tian, S C SrivastavaAbstract:Abstract Intensification of agriculture in the tropics has resulted from a shortage of farmland and insufficient food production to satisfy the needs of an expanding population. Many tropical farmers are challenged by the prospect of intensifying their production while sustaining or improving the fertility and productivity of soils with only locally available natural resources. The waste products of plant and animal production represent some of the most abundant natural resources available for use by tropical farmers to achieve these goals. The efficient use and management of these resources depends on understanding the role that decomposer biota play in regulating the structure and function of Agricultural ecosystems. Furthermore, the development of Agricultural management practices which promote the beneficial attributes of these organisms will be essential to sustaining the productivity and environmental integrity of tropical agriculture. Finally, understanding the role of biodiversity among decomposer biota in maintaining the functional properties of tropical Agricultural ecosystems is critical to achieving this goal. The objective of this review is to further that understanding by describing the taxonomic and functional diversity of decomposer biota in the tropics and evaluating known links between their diversity and the function of Agricultural ecosystems. We further describe the effects of changing land-use and Agricultural Intensification on the structure and diversity of decomposer communities in the tropics and suggest some priorities for future research.
Kenneth E. Giller - One of the best experts on this subject based on the ideXlab platform.
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Failing to Yield? Ploughs, Conservation Agriculture and the Problem of Agricultural Intensification: An Example from the Zambezi Valley, Zimbabwe
Journal of Development Studies, 2012Co-Authors: Frédéric Baudron, Marc Corbeels, Jens A Andersson, Kenneth E. GillerAbstract:Agricultural Intensification, or increasing yield, has been a persistent theme in policy interventions in African smallholder agriculture. This article focuses on two hegemonic policy models of such Intensification: (1) the ‘Alvord model’ of plough-based, integrated crop-livestock farming promoted in colonial Zimbabwe; and (2) minimum-tillage mulch-based, Conservation Agriculture, as currently preached by a wide range of international Agricultural research and development agencies. An analysis of smallholder farming practices in Zimbabwe’s Zambezi Valley, reveals the limited inherent understanding of farmer practices in these models. It shows why many smallholder farmers in southern Africa are predisposed towards extensification rather than Intensification, and suggests that widespread Conservation Agriculture adoption is unlikely.