Bats and birds increase crop yield in tropical agroforestry landscapes
TL;DR: It is found that bat and bird exclusion increased insect herbivore abundance, despite the concurrent release of mesopredators such as ants and spiders, and negatively affected fruit development, with final crop yield decreasing by 31% across local (shade cover) and landscape gradients.
Abstract: Human welfare is significantly linked to ecosystem services such as the suppression of pest insects by birds and bats. However, effects of biocontrol services on tropical cash crop yield are still largely unknown. For the first time, we manipulated the access of birds and bats in an exclosure experiment (day, night and full exclosures compared to open controls in Indonesian cacao agroforestry) and quantified the arthropod communities, the fruit development and the final yield over a long time period (15 months). We found that bat and bird exclusion increased insect herbivore abundance, despite the concurrent release of mesopredators such as ants and spiders, and negatively affected fruit development, with final crop yield decreasing by 31% across local (shade cover) and landscape (distance to primary forest) gradients. Our results highlight the tremendous economic impact of common insectivorous birds and bats, which need to become an essential part of sustainable landscape management.
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University of Würzburg1, National University of Comahue2, Spanish National Research Council3, Swedish University of Agricultural Sciences4, Universidade Federal de Goiás5, University of Lisbon6, Stanford University7, Commonwealth Scientific and Industrial Research Organisation8, National University of Río Negro9, ETH Zurich10, Cornell University11, University of California, Davis12, The Nature Conservancy13, Wageningen University and Research Centre14, University of British Columbia15, Great Lakes Bioenergy Research Center16, University of California, Santa Cruz17, University of Padua18, University of New England (Australia)19, Lund University20, University of Göttingen21, Institut national de la recherche agronomique22, University of La Rochelle23, Federal University of Ceará24, University of Freiburg25, Concordia University Wisconsin26, University of Belgrade27, National University of Tucumán28, Michigan State University29, University of Brasília30, University of Greenwich31, University of Reading32, University of Wisconsin-Madison33, National Institute of Amazonian Research34, Boise State University35, University of Texas at Austin36, University of Haifa37, Kansas State University38, University of Hamburg39, Bioversity International40, University of California, Santa Barbara41, Seattle University42, University of Vienna43, University of Florida44, Centro Agronómico Tropical de Investigación y Enseñanza45, National Audubon Society46, University of Buenos Aires47, Virginia Tech48, University of Bordeaux49, University of Auckland50, University of California, Berkeley51, University College Dublin52, Trinity College, Dublin53, University of Tokyo54, Federal University of Bahia55, Lincoln University (New Zealand)56, National Institute for Environmental Studies57, International Food Policy Research Institute58, Xi'an Jiaotong-Liverpool University59
TL;DR: Using a global database from 89 studies (with 1475 locations), the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change is partitioned.
Abstract: Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society.
434 citations
University of Göttingen1, University of British Columbia2, Stanford University3, CGIAR4, University of Wisconsin-Madison5, University of Maryland, College Park6, Swedish University of Agricultural Sciences7, University of California, Berkeley8, University of Würzburg9, Centro Agronómico Tropical de Investigación y Enseñanza10, National Ecological Observatory Network11, Virginia Tech12, Cornell University13, University of California, Davis14, Institut national de la recherche agronomique15, Commonwealth Scientific and Industrial Research Organisation16, Lincoln University (New Zealand)17, International Food Policy Research Institute18
TL;DR: In this article, the authors 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 habitats 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 bioc
400 citations
Cites background from "Bats and birds increase crop yield ..."
...Five hypotheses, Biological Conser- Cook et al., 2007; Landis et al., 2008; Maas et al., 2013; Pywell et al., 2015; Tschumi et al., 2016)....
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TL;DR: Slowing defaunation will require aggressively reducing animal overexploitation and habitat destruction; mitigating climate disruption; and stabilizing the impacts of human population growth and uneven resource consumption.
Abstract: Anthropocene defaunation, the global extinction of faunal species and populations and the decline in abundance of individuals within populations, has been predominantly documented in terrestrial ecosystems, but indicators suggest defaunation has been more severe in freshwater ecosystems. Marine defaunation is in a more incipient stage, yet pronounced effects are already apparent and its rapid acceleration seems likely. Defaunation now impacts the planet's wildlife with profound cascading consequences, ranging from local to global coextinctions of interacting species to the loss of ecological services critical for humanity. Slowing defaunation will require aggressively reducing animal overexploitation and habitat destruction; mitigating climate disruption; and stabilizing the impacts of human population growth and uneven resource consumption. Given its omnipresence, defaunation should receive status of major global environmental change and should be addressed with the same urgency as deforestation, polluti...
313 citations
Cites background from "Bats and birds increase crop yield ..."
...Recent work shows that the presence of intact bird and bat communities prevented 30% loss in cacao crop yield; the cacao crop represents a billion dollar/year industry (Maas et al. 2013)....
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TL;DR: Interaction among diverse scientists and stakeholders will be required to measure the direct and indirect costs and benefits of biological control that will allow farmers and others to internalize the benefits that incentive and accelerate adoption for private and public good.
Abstract: Biological control is an underlying pillar of integrated pest management, yet little focus has been placed on assigning economic value to this key ecosystem service. Setting biological control on a firm economic foundation would help to broaden its utility and adoption for sustainable crop protection. Here we discuss approaches and methods available for valuation of biological control of arthropod pests by arthropod natural enemies and summarize economic evaluations in classical, augmentative, and conservation biological control. Emphasis is placed on valuation of conservation biological control, which has received little attention. We identify some of the challenges of and opportunities for applying economics to biological control to advance integrated pest management. Interaction among diverse scientists and stakeholders will be required to measure the direct and indirect costs and benefits of biological control that will allow farmers and others to internalize the benefits that incentivize and accelerate adoption for private and public good.
257 citations
Cites background from "Bats and birds increase crop yield ..."
...The exclusion of ants (142) and insectivorous birds and bats (79) on Indonesian cacao, and exclusion of insectivorous birds in Jamaican coffee plantations (69), showed avoided costs of yield loss of $344–900/ha (all monetary values are in US dollars throughout)....
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University of Würzburg1, National University of Comahue2, Spanish National Research Council3, Swedish University of Agricultural Sciences4, University of Lisbon5, Universidade Federal de Goiás6, Stanford University7, Commonwealth Scientific and Industrial Research Organisation8, National University of Río Negro9, ETH Zurich10, Cornell University11, University of California, Davis12, The Nature Conservancy13, Wageningen University and Research Centre14, University of British Columbia15, Great Lakes Bioenergy Research Center16, University of California, Berkeley17, University of Padua18, University of New England (United States)19, Lund University20, University of Göttingen21, Institut national de la recherche agronomique22, University of La Rochelle23, Federal University of Ceará24, Concordia University Wisconsin25, University of Belgrade26, National University of Tucumán27, Michigan State University28, University of Brasília29, University of Greenwich30, University of Reading31, University of Wisconsin-Madison32, Boise State University33, University of Texas at Austin34, University of Haifa35, Kansas State University36, University of Freiburg37, University of Hamburg38, University of California, Santa Barbara39, Seattle University40, University of Vienna41, University of Florida42, Centro Agronómico Tropical de Investigación y Enseñanza43, National Audubon Society44, University of Buenos Aires45, Virginia Tech46, University of Bordeaux47, University of Auckland48, University College Dublin49, Trinity College, Dublin50, University of Tokyo51, Federal University of Bahia52, Lincoln University (Pennsylvania)53, National Institute for Environmental Studies54, International Food Policy Research Institute55, Xi'an Jiaotong-Liverpool University56
TL;DR: Using a global database from 89 crop systems, the relative importance of abundance and species richness for pollination, biological pest control and final yields in the context of on-going land-use change is partitioned.
Abstract: Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by few abundant species or rely on high richness remains unclear. Using a global database from 89 crop systems, we partition the relative importance of abundance and species richness for pollination, biological pest control and final yields in the context of on-going land-use change. Pollinator and enemy richness directly supported ecosystem services independent of abundance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society.
237 citations
References
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TL;DR: In this article, the authors argue that the term "ecosystem services" is too ad hoc to be of practical use in welfare accounting and propose a definition, rooted in economic principles, of ecosystem service units.
Abstract: This paper advocates consistently defined units of account to measure the contributions of nature to human welfare. We argue that such units have to date not been defined by environmental accounting advocates and that the term "ecosystem services" is too ad hoc to be of practical use in welfare accounting. We propose a definition, rooted in economic principles, of ecosystem service units. A goal of these units is comparability with the definition of conventional goods and services found in GDP and the other national accounts. We illustrate our definition of ecological units of account with concrete examples. We also argue that these same units of account provide an architecture for environmental performance measurement by governments, conservancies, and environmental markets.
1,758 citations
TL;DR: It is concluded that diversified landscapes hold most potential for the conservation of biodiversity and sustaining the pest control function and similar contributions of these landscape factors suggest that all are equally important in enhancing natural enemy populations.
Abstract: 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.
1,659 citations
TL;DR: In this article, the authors argue that the term "ecosystem services" is too ad hoc to be of practical use in welfare accounting and propose a definition, rooted in economic principles, of final ecosystem service units.
1,545 citations
University of Göttingen1, University of Canterbury2, Agricultural Research Service3, University of Western Australia4, Commonwealth Scientific and Industrial Research Organisation5, Carleton University6, Eötvös Loránd University7, Swedish University of Agricultural Sciences8, Miami University9, Helmholtz Centre for Environmental Research - UFZ10, Imperial College London11, University of Florida12, University of Würzburg13, Lüneburg University14, University of California, Berkeley15, Great Lakes Bioenergy Research Center16, James Cook University17, Australian National University18, National University of Singapore19, Wageningen University and Research Centre20
TL;DR: This review uses knowledge gained from human‐modified landscapes to suggest eight hypotheses, which it hopes will encourage more systematic research on the role of landscape composition and configuration in determining the structure of ecological communities, ecosystem functioning and services.
Abstract: Understanding how landscape characteristics affect biodiversity patterns and ecological processes at local and landscape scales is critical for mitigating effects of global environmental change. In this review, we use knowledge gained from human-modified landscapes to suggest eight hypotheses, which we hope will encourage more systematic research on
1,513 citations
TL;DR: Biodiversity has key roles at all levels of the ecosystem service hierarchy: as a regulator of underpinning ecosystem processes, as a final ecosystem service and as a good that is subject to valuation, whether economic or otherwise.
Abstract: The relationship between biodiversity and the rapidly expanding research and policy field of ecosystem services is confused and is damaging efforts to create coherent policy. Using the widely accepted Convention on Biological Diversity definition of biodiversity and work for the UK National Ecosystem Assessment we show that biodiversity has key roles at all levels of the ecosystem service hierarchy: as a regulator of underpinning ecosystem processes, as a final ecosystem service and as a good that is subject to valuation, whether economic or otherwise. Ecosystem science and practice has not yet absorbed the lessons of this complex relationship, which suggests an urgent need to develop the interdisciplinary science of ecosystem management bringing together ecologists, conservation biologists, resource economists and others.
1,412 citations