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Teja Tscharntke - One of the best experts on this subject based on the ideXlab platform.
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when natural habitat fails to enhance biological Pest Control five hypotheses
Biological Conservation, 2016Co-Authors: Teja Tscharntke, Mattias Jonsson, Daniel S Karp, Rebecca Chaplinkramer, Peter Batary, Fabrice Declerck, Claudio Gratton, Lauren Hunt, Anthony R Ives, Ashley E LarsenAbstract:Abstract Ecologists and farmers often have contrasting perceptions about the value of natural habitat in agricultural production landscapes, which so far has been little acknowledged in ecology and conservation. Ecologists and conservationists often appreciate the contribution of natural habitat to biodiversity and potential ecosystem services such as biological Pest Control, whereas many farmers see habitat remnants as a waste of cropland or source of Pests. While natural habitat has been shown to increase Pest Control in many systems, we here identify five hypotheses for when and why natural habitat can fail to support biological Pest Control, and illustrate each with case studies from the literature: (1) Pest populations have no effective natural enemies in the region, (2) natural habitat is a greater source of Pests than natural enemies, (3) crops provide more resources for natural enemies than does natural habitat, (4) natural habitat is insufficient in amount, proximity, composition, or configuration to provide large enough enemy populations needed for Pest Control, and (5) agricultural practices counteract enemy establishment and bioControl provided by natural habitat. In conclusion, we show that the relative importance of natural habitat for bioControl can vary dramatically depending on type of crop, Pest, predator, land management, and landscape structure. This variation needs to be considered when designing measures aimed at enhancing bioControl services through restoring or maintaining natural habitat.
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Agricultural landscape simplification reduces natural Pest Control: a quantitative synthesis
Agriculture Ecosystems and Environment, 2016Co-Authors: Adrien Rusch, Teja Tscharntke, Rebecca Chaplin-kramer, Mary M. Gardiner, Violetta Hawro, John Holland, Douglas Landis, Carsten Thies, Wolfgang W. Weisser, Camilla WinqvistAbstract:Numerous studies show that landscape simplification reduces abundance and diversity of natural enemies in agroecosystems, but its effect on natural Pest Control remains poorly quantified. Further, natural enemy impacts on Pest populations have usually been estimated for a limited number of taxa and have not considered interactions among predator species. In a quantitative synthesis with data collected from several cropping systems in Europe and North America, we analyzed how the level and within-field spatial stability of natural Pest Control services was related to the simplification of the surrounding landscape. All studies used aphids as a model species and exclusion cages to measure aphid Pest Control. Landscape simplification was quantified by the proportion of cultivated land within a 1 km radius around each plot. We found a consistent negative effect of landscape simplification on the level of natural Pest Control, despite interactions among enemies. Average level of Pest Control was 46% lower in homogeneous landscapes dominated by cultivated land, as compared with more complex landscapes. Landscape simplification did not affect the amount of positive or negative interactions among ground-dwelling and vegetation-dwelling predators, or the within-field stability of Pest Control. Our synthesis demonstrates that agricultural intensification through landscape simplification has negative effects on the level of natural Pest Control with important implications for management to maintain and enhance ecosystem services in agricultural landscapes. Specifically, preserving and restoring semi-natural habitats emerges as a fundamental first step to maintain and enhance Pest Control services provided by predatory arthropods to agriculture.
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bat Pest Control contributes to food security in thailand
Biological Conservation, 2014Co-Authors: Teja Tscharntke, Thomas C Wanger, Kevin Darras, Sara Bumrungsri, Alexandramaria KleinAbstract:Sustainable rice production is critical to food security especially in Asia. Effective bioControl of major rice Pests such as the White-Backed Planthopper (Sogatella furcifera, Horvath; WBP) is, hence, of eminent importance. We use newly compiled data from Thailand on the Wrinkle-Lipped Bat (Tadarida plicata, Buchanan), WBP distributions and an iterative modelling approach to quantify the importance of biological Pest Control by a common bat species on WBP. In Thailand, this single species interaction may prevent rice loss of almost 2,900 tons per year, which translates into a national economic value of more than 1.2 million USD or rice meals for almost 26,200 people annually. For the first time, our results show not only the critical importance of bat Pest Control services in economic terms, but also for sustaining food security. Thus, bat population decline as currently observed in Southeast Asia, will directly affect people by food and money. Functionally important populations, not just rare and endangered species, should be included in conservation management of human-dominated landscapes.
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sustainable Pest regulation in agricultural landscapes a review on landscape composition biodiversity and natural Pest Control
Proceedings of The Royal Society B: Biological Sciences, 2006Co-Authors: Felix J J A Bianchi, C J H Booij, Teja TscharntkeAbstract:Agricultural intensification has resulted in a simplification of agricultural landscapes by the expansion of agricultural land, enlargement of field size and removal of non-crop habitat. These changes are considered to be an important cause of the rapid decline in farmland biodiversity, with the remaining biodiversity concentrated in field edges and non-crop habitats. The simplification of landscape composition and the decline of biodiversity may affect the functioning of natural Pest Control because non-crop habitats provide requisites for a broad spectrum of natural enemies, and the exchange of natural enemies between crop and non-crop habitats is likely to be diminished in landscapes dominated by arable cropland. In this review, we test the hypothesis that natural Pest Control is enhanced in complex patchy landscapes with a high proportion of non-crop habitats as compared to simple large-scale landscapes with little associated non-crop habitat. In 74% and 45% of the studies reviewed, respectively, natural enemy populations were higher and Pest pressure lower in complex landscapes versus simple landscapes. Landscape-driven Pest suppression may result in lower crop injury, although this has rarely been documented. Enhanced natural enemy activity was associated with herbaceous habitats in 80% of the cases (e.g. fallows, field margins), and somewhat less often with wooded habitats (71%) and landscape patchiness (70%). The similar contributions of these landscape factors suggest that all are equally important in enhancing natural enemy populations. We conclude that diversified landscapes hold most potential for the conservation of biodiversity and sustaining the Pest Control function.
Adrien Rusch - One of the best experts on this subject based on the ideXlab platform.
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Agricultural landscape simplification reduces natural Pest Control: a quantitative synthesis
Agriculture Ecosystems and Environment, 2016Co-Authors: Adrien Rusch, Teja Tscharntke, Rebecca Chaplin-kramer, Mary M. Gardiner, Violetta Hawro, John Holland, Douglas Landis, Carsten Thies, Wolfgang W. Weisser, Camilla WinqvistAbstract:Numerous studies show that landscape simplification reduces abundance and diversity of natural enemies in agroecosystems, but its effect on natural Pest Control remains poorly quantified. Further, natural enemy impacts on Pest populations have usually been estimated for a limited number of taxa and have not considered interactions among predator species. In a quantitative synthesis with data collected from several cropping systems in Europe and North America, we analyzed how the level and within-field spatial stability of natural Pest Control services was related to the simplification of the surrounding landscape. All studies used aphids as a model species and exclusion cages to measure aphid Pest Control. Landscape simplification was quantified by the proportion of cultivated land within a 1 km radius around each plot. We found a consistent negative effect of landscape simplification on the level of natural Pest Control, despite interactions among enemies. Average level of Pest Control was 46% lower in homogeneous landscapes dominated by cultivated land, as compared with more complex landscapes. Landscape simplification did not affect the amount of positive or negative interactions among ground-dwelling and vegetation-dwelling predators, or the within-field stability of Pest Control. Our synthesis demonstrates that agricultural intensification through landscape simplification has negative effects on the level of natural Pest Control with important implications for management to maintain and enhance ecosystem services in agricultural landscapes. Specifically, preserving and restoring semi-natural habitats emerges as a fundamental first step to maintain and enhance Pest Control services provided by predatory arthropods to agriculture.
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flow and stability of natural Pest Control services depend on complexity and crop rotation at the landscape scale
Journal of Applied Ecology, 2013Co-Authors: Adrien Rusch, Henrik G Smith, Riccardo Bommarco, Mattias Jonsson, Barbara EkbomAbstract:Increasing landscape complexity can enhance biodiversity and ecosystem services in agroecosystems. However, policies based on conversion of arable land into semi-natural habitats to increase landscape complexity and ecosystem services can be difficult to implement. Although it appears to be a promising management option, nothing is known about the effect of increasing landscape diversity through crop rotations on the delivery of ecosystem services. In this study, we examined how landscape complexity and crop rotation intensity in the landscape at different spatial scales affect the flow and the stability of natural Pest Control services in barley fields using manipulative cage experiments. Exclusion experiments revealed that natural enemies can have a strong impact on aphid population growth and that the delivery of Pest Control services is strongly dependent on the landscape context. We found that the overall level of Pest Control increased with landscape complexity and that this effect was independent of crop rotation intensity. In addition, the within-field stability in Pest Control services increased with crop rotation intensity in the landscape, although stability in parasitism rates decreased. Multiple spatial scales analyses showed that the mean level of natural Pest Control was best predicted by landscape complexity at the 0 center dot 5-km and the 1-km spatial scales. The stability in overall Pest Control decreased with proportion of ley at the 2 center dot 5-km and the 3-km spatial scales. Synthesis and applications. Our study disentangled, for the first time, the relative effects of landscape complexity and crop rotation intensity on the delivery of an ecosystem service. We show that combined management of semi-natural habitat and crop rotation can stabilize and enhance natural Pest Control in agricultural landscapes. Our findings have important implications in terms of management options to maintain and enhance ecosystem services in agroecosystems. They suggest that conservation of heterogeneous landscapes, characterized by a higher proportion of semi-natural habitats such as pastures and relatively small fields, is essential for maintaining and enhancing effective biological Control in agroecosystems.
Katja Jacot - One of the best experts on this subject based on the ideXlab platform.
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tailored flower strips promote natural enemy biodiversity and Pest Control in potato crops
Journal of Applied Ecology, 2016Co-Authors: Matthias Tschumi, Jana Collatz, Matthias Albrecht, Martin H. Entling, Viktor Dubsky, Adriana J Najarrodriguez, Katja JacotAbstract:Sown flower strips are increasingly implemented within agri-environment schemes (AES) to increase functional biodiversity and ecosystem services such as pollination or natural Pest Control, but their effectiveness in achieving these goals remains poorly studied. We tested the performance of experimentally sown annual flower strips specifically designed to promote natural enemies of aphids and their Pest Control services (tailored flower strips) in adjacent potato crops (n = 8) compared with Control fields (n = 10). Flower strips consisted of 11 plant species providing abundant floral and extra-floral resources. The abundance of key natural enemies of aphids (hoverflies, lacewings and ladybirds) and hoverfly species richness was greatly enhanced in tailored flower strips compared with potato Control strips. This resulted in an average increase in the number of eggs deposited by hoverflies and lacewings by 127% and 48%, respectively, and a reduction in the number of aphids by 75% in adjacent potato crops. Synthesis and applications. We conclude that tailored flower strips can be an effective agri-environmental measure to enhance natural enemies and aphid Control in nearby crops. Indeed, tailored flower strips may help to reduce insecticide input in potato production as they significantly decrease the probability that action thresholds are reached. Promoting natural enemy abundance and diversity, as observed for hoverflies, may increase the stability of Pest Control and provide additional benefits to agro-ecosystems in terms of natural enemy conservation. We thus recommend establishing tailored flower strips as a promising management option to reconcile the objectives of ecological intensification and biodiversity conservation.
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perennial species rich wildflower strips enhance Pest Control and crop yield
Agriculture Ecosystems & Environment, 2016Co-Authors: Matthias Tschumi, Cedric Bartschi, Jana Collatz, Matthias Albrecht, Martin H. Entling, Katja JacotAbstract:The effectiveness of agri-environment schemes (AES) such as wildflower strips in promoting farmland biodiversity has been relatively well studied. Their effects on biodiversity-mediated ecosystem services, such as natural Pest Control, in contrast, remain poorly evaluated and their consequences on crop yield largely unexplored. We assessed the effect of sown, species-rich, perennial wildflower strips, promoted through the Swiss AES, on Pest Control services and their consequences for crop yield in nearby winter wheat. We found strong reductions in cereal leaf beetle Oulema sp. (CLB) density (eggs: 44%, larvae: 66%) and crop damage (40%) caused by CLB in winter wheat besides wildflower strips (N = 10) compared with Control fields without wildflower strip (N = 10). Moreover, average crop yield was increased by 10% in winter wheat next to wildflower strips up to 10 m into the fields. Wheat yield was positively associated with broad leaved plant cover, flower density and diversity of nearby flower strips, yet collinearity with wheat density made these effects difficult to disentangle. Our study demonstrates that diverse wildflower strips with known benefits for farmland biodiversity can also promote biological Pest Control and crop yield. This creates a win-win situation for crop production and biodiversity conservation, through which such AES may contribute to ecological intensification. (Less)
Ingolf Steffandewenter - One of the best experts on this subject based on the ideXlab platform.
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natural enemy interactions constrain Pest Control in complex agricultural landscapes
Proceedings of the National Academy of Sciences of the United States of America, 2013Co-Authors: Emily A Martin, Bjorn Reineking, Bumsuk Seo, Ingolf SteffandewenterAbstract:Biological Control of Pests by natural enemies is a major ecosystem service delivered to agriculture worldwide. Quantifying and predicting its effectiveness at large spatial scales is critical for increased sustainability of agricultural production. Landscape complexity is known to benefit natural enemies, but its effects on interactions between natural enemies and the consequences for crop damage and yield are unclear. Here, we show that Pest Control at the landscape scale is driven by differences in natural enemy interactions across landscapes, rather than by the effectiveness of individual natural enemy guilds. In a field exclusion experiment, Pest Control by flying insect enemies increased with landscape complexity. However, so did antagonistic interactions between flying insects and birds, which were neutral in simple landscapes and increasingly negative in complex landscapes. Negative natural enemy interactions thus constrained Pest Control in complex landscapes. These results show that, by altering natural enemy interactions, landscape complexity can provide ecosystem services as well as disservices. Careful handling of the tradeoffs among multiple ecosystem services, biodiversity, and societal concerns is thus crucial and depends on our ability to predict the functional consequences of landscape-scale changes in trophic interactions.
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decreased functional diversity and biological Pest Control in conventional compared to organic crop fields
PLOS ONE, 2011Co-Authors: Ingolf Steffandewenter, Jochen Krauss, Iris GallenbergerAbstract:Organic farming is one of the most successful agri-environmental schemes, as humans benefit from high quality food, farmers from higher prices for their products and it often successfully protects biodiversity. However there is little knowledge if organic farming also increases ecosystem services like Pest Control. We assessed 30 triticale fields (15 organic vs. 15 conventional) and recorded vascular plants, pollinators, aphids and their predators. Further, five conventional fields which were treated with insecticides were compared with 10 non-treated conventional fields. Organic fields had five times higher plant species richness and about twenty times higher pollinator species richness compared to conventional fields. Abundance of pollinators was even more than one-hundred times higher on organic fields. In contrast, the abundance of cereal aphids was five times lower in organic fields, while predator abundances were three times higher and predator-prey ratios twenty times higher in organic fields, indicating a significantly higher potential for biological Pest Control in organic fields. Insecticide treatment in conventional fields had only a short-term effect on aphid densities while later in the season aphid abundances were even higher and predator abundances lower in treated compared to untreated conventional fields. Our data indicate that insecticide treatment kept aphid predators at low abundances throughout the season, thereby significantly reducing top-down Control of aphid populations. Plant and pollinator species richness as well as predator abundances and predator-prey ratios were higher at field edges compared to field centres, highlighting the importance of field edges for ecosystem services. In conclusion organic farming increases biodiversity, including important functional groups like plants, pollinators and predators which enhance natural Pest Control. Preventative insecticide application in conventional fields has only short-term effects on aphid densities but long-term negative effects on biological Pest Control. Therefore conventional farmers should restrict insecticide applications to situations where thresholds for Pest densities are reached.
Matthias Albrecht - One of the best experts on this subject based on the ideXlab platform.
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tailored flower strips promote natural enemy biodiversity and Pest Control in potato crops
Journal of Applied Ecology, 2016Co-Authors: Matthias Tschumi, Jana Collatz, Matthias Albrecht, Martin H. Entling, Viktor Dubsky, Adriana J Najarrodriguez, Katja JacotAbstract:Sown flower strips are increasingly implemented within agri-environment schemes (AES) to increase functional biodiversity and ecosystem services such as pollination or natural Pest Control, but their effectiveness in achieving these goals remains poorly studied. We tested the performance of experimentally sown annual flower strips specifically designed to promote natural enemies of aphids and their Pest Control services (tailored flower strips) in adjacent potato crops (n = 8) compared with Control fields (n = 10). Flower strips consisted of 11 plant species providing abundant floral and extra-floral resources. The abundance of key natural enemies of aphids (hoverflies, lacewings and ladybirds) and hoverfly species richness was greatly enhanced in tailored flower strips compared with potato Control strips. This resulted in an average increase in the number of eggs deposited by hoverflies and lacewings by 127% and 48%, respectively, and a reduction in the number of aphids by 75% in adjacent potato crops. Synthesis and applications. We conclude that tailored flower strips can be an effective agri-environmental measure to enhance natural enemies and aphid Control in nearby crops. Indeed, tailored flower strips may help to reduce insecticide input in potato production as they significantly decrease the probability that action thresholds are reached. Promoting natural enemy abundance and diversity, as observed for hoverflies, may increase the stability of Pest Control and provide additional benefits to agro-ecosystems in terms of natural enemy conservation. We thus recommend establishing tailored flower strips as a promising management option to reconcile the objectives of ecological intensification and biodiversity conservation.
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perennial species rich wildflower strips enhance Pest Control and crop yield
Agriculture Ecosystems & Environment, 2016Co-Authors: Matthias Tschumi, Cedric Bartschi, Jana Collatz, Matthias Albrecht, Martin H. Entling, Katja JacotAbstract:The effectiveness of agri-environment schemes (AES) such as wildflower strips in promoting farmland biodiversity has been relatively well studied. Their effects on biodiversity-mediated ecosystem services, such as natural Pest Control, in contrast, remain poorly evaluated and their consequences on crop yield largely unexplored. We assessed the effect of sown, species-rich, perennial wildflower strips, promoted through the Swiss AES, on Pest Control services and their consequences for crop yield in nearby winter wheat. We found strong reductions in cereal leaf beetle Oulema sp. (CLB) density (eggs: 44%, larvae: 66%) and crop damage (40%) caused by CLB in winter wheat besides wildflower strips (N = 10) compared with Control fields without wildflower strip (N = 10). Moreover, average crop yield was increased by 10% in winter wheat next to wildflower strips up to 10 m into the fields. Wheat yield was positively associated with broad leaved plant cover, flower density and diversity of nearby flower strips, yet collinearity with wheat density made these effects difficult to disentangle. Our study demonstrates that diverse wildflower strips with known benefits for farmland biodiversity can also promote biological Pest Control and crop yield. This creates a win-win situation for crop production and biodiversity conservation, through which such AES may contribute to ecological intensification. (Less)
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synergistic interactions of ecosystem services florivorous Pest Control boosts crop yield increase through insect pollination
Proceedings of The Royal Society B: Biological Sciences, 2016Co-Authors: Louis Sutter, Matthias AlbrechtAbstract:Insect pollination and Pest Control are pivotal functions sustaining global food production. However, they have mostly been studied in isolation and how they interactively shape crop yield remains ...
