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Pollination ecosystem services: A comprehensive review of economic values, research funding and policy actions

Food Security volume 12, pages 1425–1442 (2020)Cite this article

Abstract

Economic valuation of crop pollination services, including potential monetary losses in agricultural production induced by insufficient pollination, is a strategy to quantify the impacts of this critical ecosystem service on food production, food security and the global economy, and to drive policy actions. We examined how the economic valuation of crop pollination services has been investigated across the ecological and economics literature and review estimates of monetary values of crop pollination services, as well as the investments (research funding/grants) and policy actions associated with pollinators and pollination. We documented an increase in the number of economic valuation studies on pollination services in the last two decades, with a substantial growth over the last five years, which represented 54% of all publications. However, we emphasize that there is a marked lack of data on regionally important commercial crops that are essential for the food security of many millions of people, particularly in developing countries. Estimated global values of the crop pollination service, adjusted for inflation in March/2020, range widely from US$195 billion to ~US$387 (US$267–657) billion annually — due to methodology, input data and a historical increase in production costs of pollinator-dependent crops. There is an increasing trend over time in the values of crop pollination service estimates for the full set of main globally-grown crops, although estimates for specific crops are widely variable at local to regional scales. Research funding on pollination/pollinators is mainly in developed countries, which have published all the reviewed policy papers on the economic value of crop pollination services. Although the valuation of pollination services, and associated economics and policy remain embryonic areas of research, animal-mediated pollination is clearly a high-value environmental service, which greatly strengthens conservation arguments worldwide.

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References

  • Abson, D. J., & Termansen, M. (2011). Valoración de los Servicios del Ecosistema en Términos de Riesgos y Beneficios Ecológicos. Conservation Biology, 25(2), 250–258.

    PubMed  Google Scholar 

  • Aguilar, R., & Galetto, L. (2004). Effects of forest fragmentation on male and female reproductive success in Cestrum parqui (Solanaceae). Oecologia, 138(4), 513–520.

    PubMed  Google Scholar 

  • Aguilar, R., Ashworth, L., Galetto, L., & Aizen, M. A. (2006). Plant reproductive susceptibility to habitat fragmentation: Review and synthesis through a meta-analysis. Ecology Letters, 9(8), 968–980.

    PubMed  Google Scholar 

  • Allsopp, M. H., de Lange, W. J., & Veldtman, R. (2008). Valuing insect pollination services with cost of replacement. PLoS One, 3(9), e3128.

    PubMed  PubMed Central  Google Scholar 

  • Basu, P., Bhattacharya, R., & Iannetta, P. (2011). A decline in pollinator dependent vegetable crop productivity in India indicates pollination limitation and consequent agro-economic crises. Nature Precedings. https://doi.org/10.1038/npre.2011.6044.1.

  • Bauer, D. M., & Wing, I. S. (2016). The macroeconomic cost of catastrophic pollinator declines. Ecological Economics, 126, 1–13.

    Google Scholar 

  • Bojanic, A. H. (2017). The rapid agricultural development of Brazil in the last 20 years. Euro Choice, 16(1), 5–10.

    Google Scholar 

  • Bos, M. M., Veddeler, D., Bogdanski, A. K., Klein, A., Tscharntke, T., Steffan-Dewenter, I., et al. (2007). Caveats to quantifying ecosystem services: Fruit abortion blurs benefits from crop pollination. Ecological Applications, 17(6), 1841–1849.

    PubMed  Google Scholar 

  • Bravo-Monroy, L., Tzanopoulos, J., & Potts, S. G. (2015). Ecological and social drivers of coffee pollination in Santander, Colombia. Agriculture, Ecosystems and Environment, 211, 145–154.

    Google Scholar 

  • Breeze, T. D., Bailey, A. P., Potts, S. G., & Balcombe, K. G. (2015). A stated preference valuation of the non-market benefits of pollination services in the UK. Ecological Economics, 111, 76–85.

    Google Scholar 

  • Breeze, T. D., Gallai, N., Garibaldi, L. A., & Li, X. S. (2016). Economic measures of pollination services: Shortcomings and future directions. Trends in Ecology and Evolution, 31(12), 927–939.

    PubMed  Google Scholar 

  • Calderone, N. W. (2012). Insect pollinated crops, insect pollinators and US agriculture: Trend analysis of aggregate data for the period 1992-2009. PLoS One, 7(5), e37235.

    CAS  PubMed  PubMed Central  Google Scholar 

  • Costanza, R., Arge, R., Groot, R., Farber, S., Grasso, M., Hannon, B., et al. (1997). The value of the world ‘s ecosystem services and natural capital. Nature, 387, 253–260.

    CAS  Google Scholar 

  • Costanza, R., Groot, R., Sutton, P., van der Ploeg, S., Anderson, S. J., Kubiszewski, I., et al. (2014). Changes in the global value of ecosystem services. Global Environmental Change, 26, 152–158.

    Google Scholar 

  • Cunningham, S. A., & Le Feuvre, D. (2013). Significant yield benefits from honeybee pollination of faba bean (Vicia faba) assessed at field scale. Field Crops Research, 149, 269–275.

    Google Scholar 

  • De Marco, P. D. E., & Coelho, F. M. (2004). Services performed by the ecosystem: Forest remnants influence agricultural cultures’ pollination and production. Biodiversity and Conservation, 13, 1245–1255.

    Google Scholar 

  • Dicks, L. V., Viana, B., Bommarco, R., Brosi, B., Arizmendi, C., Cunningham, et al. (2016). Ten policies for pollinators. What governments can do to safeguard pollination services. Science, 354(6315), 14–15.

    Google Scholar 

  • Dimensions Platform. 2018. Available at https://app.dimensions.ai. Accessed on November 15, 2018, under licence agreement.

  • EMBRAPA (2016). Amazônia é berço de frutas nativas de alto potencial comercial. Empresa Brasileira de Pesquisa Agropecuária, Ministério da Agricultura, Pecuária e Abastecimento. https://www.embrapa.br/busca-de-noticias/-/noticia/14818376/amazonia-e-berco-de-frutas-nativas-de-alto-potencial-comercial.pdf. Accessed in January 2017.

  • Eilers, E. J., Kremen, C., Greenleaf, S. S., Garber, A. K., & Klein, A. M. (2011). Contribution of pollinator-mediated crops to nutrients in the human food supply. PLoS One, 6(6), e21363.

    CAS  PubMed  PubMed Central  Google Scholar 

  • FAOSTAT (2018). FAO - food and agriculture Organization of the United Nations. Resource document. http://www.fao.org/faostat/en/#data/QC. Accessed 1 November 2018.

  • Gallai, N., & Vaissière, B. E. (2009). Guidelines for the economic valuation of pollination services at national scale. FAO. http://www.fao.org/3/a-at523e.pdf. Accessed 1 November 2018.

  • Gallai, N., Salles, J., Settele, J., Vaissière, B. E., Pollinisation, L., Abeilles, et al. (2009). Economic valuation of the vulnerability of world agriculture confronted with pollinator decline. Ecological Economics, 68(3), 810–821.

    Google Scholar 

  • Garibaldi, L. A., Carvalheiro, L. G., Leonhardt, S. D., Aizen, M. A., Blaauw, B. R., Isaacs, R., Kuhlmann, M., Kleijn, D., Klein, A. M., Kremen, C., Morandin, L., Scheper, J., & Winfree, R. (2014). From research to action: Enhancing crop yield through wild pollinators. Frontiers in the Ecology and Environment, 12(8), 439–447.

    Google Scholar 

  • Garibaldi, L. A., Carvalheiro, L. G., Vaissière, B. E., Gemmill-Herren, B., Hipólito, J., Freitas, B. M., et al. (2016). Mutually beneficial pollinator diversity and crop yield outcomes in small and large farms. Science, 351(6271), 388–391.

    CAS  PubMed  Google Scholar 

  • Garratt, M. P. D., Breeze, T. D., Jenner, N., Polce, C., Biesmeijer, J. C., & Potts, S. G. (2014). Avoiding a bad apple: Insect pollination enhances fruit quality and economic value. Agriculture, Ecosystems and Environment, 184, 34–40.

    CAS  PubMed  Google Scholar 

  • Giannini, T. C., Acosta, A. L., Garófalo, C. A., Saraiva, A. M., Alves-dos-Santos, I., & Imperatriz-Fonseca, V. L. (2012). Pollination services at risk: Bee habitats will decrease owing to climate change in Brazil. Ecological Modelling, 244, 127–131.

    Google Scholar 

  • Giannini, T. C., Boff, S., Cordeiro, G. D., Cartolano, E. A., Veiga, A. K., Imperatriz-Fonseca, V. L., et al. (2015a). Crop pollinators in Brazil: A review of reported interactions. Apidologie, 46(2), 209–223.

    Google Scholar 

  • Giannini, T. C., Cordeiro, G. D., Freitas, B. M., Saraiva, A. M., & Imperatriz-Fonseca, V. L. (2015b). The dependence of crops for pollinators and the economic value of pollination in Brazil. Journal of Economic Entomology, 108(3), 849–857.

    CAS  PubMed  Google Scholar 

  • Gibbs, J., Elle, E., Bobiwash, K., Haapalainen, T., & Isaacs, R. (2016). Contrasting pollinators and pollination in native and non-native regions of highbush blueberry production. PLoS One, 11(7), e0158937.

    PubMed  PubMed Central  Google Scholar 

  • Girão, L. C., Lopes, A. V., Tabarelli, M., & Bruna, E. M. (2007). Changes in tree reproductive traits reduce functional diversity in a fragmented Atlantic forest landscape. PLoS One, 2(9), e908.

    PubMed  PubMed Central  Google Scholar 

  • Goñi, E., & Maloney, W. F. (2017). Why don’t poor countries do R&D? Varying rates of factor returns across the development process. European Economic Review, 94, 126–147.

    Google Scholar 

  • Greenleaf, S. S., & Kremen, C. (2006). Wild bees enhance honey bees’ pollination of hybrid sunflower. Proceedings of the National Academy of Sciences of the United States of America, 103, 13890–13895.

    CAS  PubMed  PubMed Central  Google Scholar 

  • Gret-Regamey, A., Rabe, S., Crespo, R., Lautenbach, S., Ryffel, A., & Schlup, B. (2014). On the importance of non-linear relationships between landscape patterns and the sustainable provision of ecosystem services. Landscape Ecology, 29, 201–212.

    Google Scholar 

  • Hanley, N., Breeze, T. D., Ellis, C., & Goulson, D. (2015). Measuring the economic value of pollination services: Principles, evidence and knowledge gaps. Ecosystem Services, 14, 124–132.

    Google Scholar 

  • Hein, L. (2009). The economic value of the pollination service, a review across scales. The Open Ecology Journal, 2(1), 74–82.

    Google Scholar 

  • Hipólito, J., Viana, B. F., & Garibaldi, L. A. (2016). The value of pollinator-friendly practices: Synergies between natural and anthropogenic assets. Basic and Applied Ecology, 17(8), 659–667.

    Google Scholar 

  • Hipólito, J., Boscolo, D., & Viana, B. F. (2018). Landscape and crop management strategies to conserve pollination services and increase yields in tropical coffee farms. Agriculture, Ecosystems and Environment, 256, 218–225.

    Google Scholar 

  • Hook, D. W., Porter, S. J., & Herzog, C. (2018). Dimensions: Building context for search and evaluation. Frontiers in Research Metrics and Analytics, 3, 1–11.

    Google Scholar 

  • Hubbard, C., Alvim, A. M., & Garrod, G. (2017). Brazilian agriculture as a global player. EuroChoices, 16(1), 3–4.

    Google Scholar 

  • IPBES (2016). The assessment report of the intergovernmental science-policy Platform on biodiversity and ecosystem services on pollinators, pollination and food production. S.G. Potts, V. L. Imperatriz-Fonseca, and H. T. Ngo (eds). Secretariat of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, Bonn, Germany. 552 pages. https://doi.org/10.5281/zenodo.3402856.

  • JianDong, A., & Chen, W. F. (2011). Economic value of insect pollination for fruits and vegetables in China. Acta Entomologica Sinica, 54(4), 443–450.

    Google Scholar 

  • Klatt, B. K., Holzschuh, A., Westphal, C., Clough, Y., Smit, I., Pawelzik, E., et al. (2014). Bee pollination improves crop quality, shelf life and commercial value. Proceedings. Biological Sciences / The Royal Society, 281(1775), 20132440.

    Google Scholar 

  • Klein, A. M., Vaissière, B. E., Cane, J. H., Steffan-Dewenter, I., Cunningham, S. A., Kremen, C., & Tscharntke, T. (2007). Importance of pollinators in changing landscapes for world crops. Proceedings. Biological Sciences / The Royal Society, 274(1608), 303–313.

    Google Scholar 

  • Knapp, J. L., & Osborne, J. L. (2017). Courgette production: Pollination demand, supply, and value. Journal Economic Entomology, 110, 1973–1979.

    Google Scholar 

  • Kovács-Hostyánszki, A., Anahí-Espíndola, A., Vanbergen, A. J., Settele, J., Kremen, C., & Dicks, L. V. (2017). Ecological intensification to mitigate impacts of conventional intensive land use on pollinators and pollination. Ecology Letters, 20, 673–689.

    PubMed  PubMed Central  Google Scholar 

  • Lautenbach, S., Seppelt, R., Liebscher, J., & Dormann, C. F. (2012). Spatial and temporal trends of global pollination benefit. PLoS One, 7(4), e35954.

    CAS  PubMed  PubMed Central  Google Scholar 

  • Leonhardt, S. D., Gallai, N., Garibaldi, L. A., Kuhlmann, M., & Klein, A. M. (2013). Economic gain, stability of pollination and bee diversity decrease from southern to northern Europe. Basic and Applied Ecology, 14(6), 461–471.

    Google Scholar 

  • Llorens, T. M., Byrne, M., Yates, C. J., Nistelberger, H. M., & Coates, D. J. (2012). Evaluating the influence of different aspects of habitat fragmentation on mating patterns and pollen dispersal in the bird-pollinated Banksia sphaerocarpa var. caesia. Molecular Ecology, 21(2), 314–328.

    CAS  PubMed  Google Scholar 

  • Lopes, A. V., Girão, L. C., Santos, B. A., Peres, C. A., & Tabarelli, M. (2009). Long-term erosion of tree reproductive trait diversity in edge-dominated Atlantic forest fragments. Biological Conservation, 142(6), 1154–1165.

    Google Scholar 

  • Lye, G. C., Jennings, S. N., Osborne, J. L., & Goulson, D. (2011). Impacts of the use of nonnative commercial bumble bees for pollinator supplementation in raspberry. Journal of Economic Entomology, 104, 107–114.

    CAS  PubMed  Google Scholar 

  • MAPA. (2017). Estatísticas e dados básicos de economia agrícola - 2015. MAPA - Ministério da Agricultura, Pecuária e Abastecimento. http://www.agricultura.gov.br/arq_editor/Pasta de Novembro - 2015.pdf. Accessed 10 December 2017.

  • Matheson, A., & Schrader, M. (1987). The value of bees to New Zealand’s primary production. Nelson (New Zealand): Ministry of Agricolture and Ficheries. 5p.

  • Meinhold, K., Adam, Y.O., & Munthali, C.R.Y. (2016). The BAOFOOD project: Enhancing local food security and nutrition in eastern Tropentag 2016, Vienna, Austria September 18–21.

  • Milojević, S., & Leydesdorff, L. (2013). Information metrics (iMetrics): A research specialty with a socio-cognitive identity? Scientometrics, 95, 141–157.

    Google Scholar 

  • Moher, D., Liberati, A., Tetzlaff, J., The, A. D. G., & PRISMA Group. (2009). Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Medicine, 6(7), e1000097.

    PubMed  PubMed Central  Google Scholar 

  • Moreddu, C., Contini, E., & Ávila, F. (2017). Challenges for the Brazilian agricultural innovation system. EuroChoices, 16(1), 26–31.

    Google Scholar 

  • Oliveira, W., Silva, J. L. S., Porto, R. G., Cruz-Neto, O., Tabarelli, M., Viana, B. F., Peres, C. A., Lopes, A. V., & 62 signatories. (2020). Plant and pollination blindness: Risky business for human food security. BioScience, 70(2), 109–110.

    Google Scholar 

  • Ollerton, J., Winfree, R., & Tarrant, S. (2011). How many flowering plants are pollinated by animals? Oikos, 120, 321–326.

    Google Scholar 

  • Olschewski, R., Tscharntke, T., Benítez, P. C., Schwarze, S., & Klein, A. M. (2006). Economic evaluation of pollination services comparing coffee landscapes in Ecuador and Indonesia. Ecology and Society, 11(1), 7.

    Google Scholar 

  • Pimentel, D., Wilson, C., McCullum, C., Huang, R., Dwen, P., Flack, J., Tran, Q., Saltman, T., & Cliff, B. (1997). Economic and environmental benefits of biodiversity. BioScience, 47(11), 747–757.

    Google Scholar 

  • Potts, S. G., Biesmeijer, J. C., Kremen, C., Neumann, P., Schweiger, O., & Kunin, W. E. (2010). Global pollinator declines: Trends, impacts and drivers. Trends in Ecology and Evolution, 25(6), 345–353.

    PubMed  Google Scholar 

  • Potts, S. G., Imperatriz-Fonseca, V., Ngo, H. T., Aizen, M. A., Biesmeijer, J. C., Breeze, T. D., Dicks, L. V., Garibaldi, L. A., Hill, R., Settele, J., & Vanbergen, A. J. (2016). Safeguarding pollinators and their values to human well-being. Nature, 540, 220–229.

    CAS  PubMed  Google Scholar 

  • Radford, K. G., & James, P. (2013). Changes in the value of ecosystem services along a rural-urban gradient: A case study of greater Manchester, UK. Landscape and Urban Planning, 109(1), 117–127.

    Google Scholar 

  • Ricketts, T. H., Daily, G. C., Ehrlich, P. R., & Michener, C. D. (2004). Economic value of tropical forest to coffee production. Proceedings of the National Academy of Sciences of the United States of America, 101(34), 12579–12582.

    CAS  PubMed  PubMed Central  Google Scholar 

  • Ricketts, T. H., Regetz, J., Steffan-Dewenter, I., Cunningham, S. A., Kremen, C., Bogdanski, A., Gemmill-Herren, B., Greenleaf, S. S., Klein, A. M., Mayfield, M. M., Morandin, L. A., Ochieng', A., Potts, S. G., & Viana, B. F. (2008). Landscape effects on crop pollination services: Are there general patterns? Ecology Letters, 11(5), 499–515.

    PubMed  Google Scholar 

  • Robinson, W. S., Nowogrodzki, R., & Morse, R. A. (1989). The value of honey bees as pollinators of U.S. crops: Part II. America Bee Journal, 129, 477–487.

    Google Scholar 

  • Sandhu, H., Waterhouse, B., Boyer, S., & Wratten, S. (2016). Scarcity of ecosystem services: An experimental manipulation of declining pollination rates and its economic consequences for agriculture. PeerJ, 4, e2099.

    PubMed  PubMed Central  Google Scholar 

  • Schreckinger, M. E., Lotton, J., Lila, M. A., & Mejia, E. G. (2010). Berries from South America: A comprehensive review on chemistry, health potential, and commercialization. Journal of Medicinal Food, 13, 233–246.

    CAS  PubMed  Google Scholar 

  • SCImago (2018). SJR – SCImago Journal & Country Rank. https://www.scimagoir.com/. Accessed 01 November 2018.

  • Stanley, D. A., Gunning, D., & Stout, J. C. (2013). Pollinators and pollination of oilseed rape crops (Brassica napus L.) in Ireland: Ecological and economic incentives for pollinator conservation. Journal of Insect Conservation, 17, 1181–1189.

    Google Scholar 

  • Tabarelli, M., Aguiar, A. V., Ribeiro, M. C., Metzger, J. P., & Peres, C. A. (2010). Prospects for biodiversity conservation in the Atlantic Forest: Lessons from aging human-modified landscapes. Biological Conservation, 143(10), 2328–2340.

    Google Scholar 

  • Timberlake, T., & Morgan, V. (2018). Pollination and international development what do we know, what are the challenges and what more can we do? Report for the UK collaborative on development Sciences. London.

  • United Nations (2019). World economic situation prospects 2019. Department of Economic and Social Affairs, United Nation publication, Sales No.E.19.II.C.1. 218 p.

  • Viana, B. F., Boscolo, D. N., Lopes, E. M., Lopes, A. V., Ferreira, P. A., Pigozzo, C. M., & Primo, L. M. (2012). How well do we understand landscape effects on pollinators and pollination services? Journal of Pollination Ecology, 7, 31–41.

    Google Scholar 

  • Whittington, R., Winston, M. L., Tucker, C., & Parachnowitsch, A. L. (2004). Plant-species identity of pollen collected by bumblebees placed in greenhouses for tomato pollination. Canadian Journal of Plant Science, 84, 599–602.

    Google Scholar 

  • Winfree, R., Gross, B. J., & Kremen, C. (2011). Valuing pollination services to agriculture. Ecological Economics, 71, 80–88.

    Google Scholar 

  • Xiao, Y., Xiaohong, L., Cao, Y., & Dong, M. (2016). The diverse effects of habitat fragmentation on plant-pollinator interactions. Plant Ecology, 217, 857–868.

    Google Scholar 

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Acknowledgments

RFA and RGP were supported by MSc and PhD studentships, respectively, granted by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES; #001). We thank PNPD/CAPES and the Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco (FACEPE) for a postdoctoral fellowship awarded to OCN (APQ0789-2.05/16 and BCT–0208-2.05/17). AVL, MT and BFV were awarded with research productivity grants from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for their research work. Data on Research funding/Grants and Policy documents were kindly provided by Digital Science’s Dimensions Platform (2018), an inter-linked research information system (https://app.dimensions.ai).

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Authors and Affiliations

  1. Programa de Pós-Graduação em Biologia Vegetal, Departamento de Botânica, Universidade Federal de Pernambuco, Recife, Pernambuco, 50372-970, Brazil

    Rafaella Guimarães Porto & Rita Fernandes de Almeida

  2. Departamento de Botânica, Universidade Federal de Pernambuco, Recife, Pernambuco, 50372-970, Brazil

    Oswaldo Cruz-Neto, Marcelo Tabarelli & Ariadna Valentina Lopes

  3. Instituto de Biologia, Universidade Federal da Bahia, Salvador, Bahia, 40170-210, Brazil

    Blandina Felipe Viana

  4. School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK

    Carlos A. Peres

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  1. Rafaella Guimarães Porto
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Porto, R.G., de Almeida, R.F., Cruz-Neto, O. et al. Pollination ecosystem services: A comprehensive review of economic values, research funding and policy actions. Food Sec. 12, 1425–1442 (2020). https://doi.org/10.1007/s12571-020-01043-w

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Keywords

  • Animal-mediated pollination
  • Agriculture
  • Food security
  • Monetary values
  • Pollinator-dependent crops
  • Scientometrics