Editing Pollinator decline (section)

==Evidence==
{{See also|Colony collapse disorder}}
The declines in abundance and diversity of insect pollinators over the twentieth century have been documented in highly industrialized regions of the world, particularly northwestern Europe and eastern North America.<ref>{{cite journal |last1=Potts |first1=Simon G. |last2=Biesmeijer |first2=Jacobus C. |last3=Kremen |first3=Claire |last4=Neumann |first4=Peter |last5=Schweiger |first5=Oliver |last6=Kunin |first6=William E. |title=Global pollinator declines: trends, impacts and drivers |journal=Trends in Ecology & Evolution |date=June 2010 |volume=25 |issue=6 |pages=345–353 |doi=10.1016/j.tree.2010.01.007 |pmid=20188434 |bibcode=2010TEcoE..25..345P |url=https://www.sciencedirect.com/science/article/pii/S0169534710000364|url-access=subscription }}</ref><ref>{{cite journal |last1=Goulson |first1=D. |last2=Nicholls |first2=E. |last3=Botias |first3=C. |last4=Rotheray |first4=E. L. |title=Bee declines driven by combined stress from parasites, pesticides, and lack of flowers |journal=Science |date=27 March 2015 |volume=347 |issue=6229 |pages=1255957 |doi=10.1126/science.1255957 |pmid=25721506 |s2cid=206558985 |doi-access=free }}</ref><ref>{{cite journal |last1=Potts |first1=Simon G. |last2=Imperatriz-Fonseca |first2=Vera |last3=Ngo |first3=Hien T. |last4=Aizen |first4=Marcelo A. |last5=Biesmeijer |first5=Jacobus C. |last6=Breeze |first6=Thomas D. |last7=Dicks |first7=Lynn V. |last8=Garibaldi |first8=Lucas A. |last9=Hill |first9=Rosemary |last10=Settele |first10=Josef |last11=Vanbergen |first11=Adam J. |title=Safeguarding pollinators and their values to human well-being |journal=Nature |date=December 2016 |volume=540 |issue=7632 |pages=220–229 |doi=10.1038/nature20588 |pmid=27894123 |bibcode=2016Natur.540..220P |hdl=11336/66239 |s2cid=205252584 |url=https://www.nature.com/articles/nature20588|hdl-access=free }}</ref>

[[Colony collapse disorder]] has attracted much public attention. According to a 2013 blog the winter losses of beehives had increased in recent years in Europe and the United States, with a hive failure rate up to 50%.<ref>{{cite web|url=http://e360.yale.edu/features/declining_bee_populations_pose_a_threat_to_global_agriculture|title=Declining Bee Populations Pose a Threat to Global Agriculture|publisher=Yale Environment 360|date=30 April 2013}}</ref>

A 2017 German study, using 1,500 samples from 63 sites, indicated that the biomass of flying insects in that area had declined by three-quarters in the previous 25 years.<ref>{{cite news|url=https://www.theguardian.com/environment/2017/oct/18/warning-of-ecological-armageddon-after-dramatic-plunge-in-insect-numbers|title=Warning of 'ecological Armageddon' after dramatic plunge in insect numbers|newspaper=The Guardian|date=18 October 2017|last1=Editor|first1=Damian Carrington Environment}}</ref> One 2009 study stated that while the bee population had increased by 45% over the past 50 years, the amount of crops which use bees had increased by 300%; although there is absolutely no evidence this has caused any problems, the authors propose it might cause "future pollination problems".<ref name=Aizen2009>{{cite journal |last1=Aizen |first1=Marcelo A. |last2=Harder |first2=Lawrence D. |date=9 June 2009 |title=The Global Stock of Domesticated Honey Bees Is Growing Slower Than Agricultural Demand for Pollination |url=https://www.cell.com/action/showPdf?pii=S0960-9822%2809%2900982-8 |journal=Current Biology |volume=19 |issue=11 |pages=915–918 |doi=10.1016/j.cub.2009.03.071 |pmid=19427214 |s2cid=12353259 |access-date=10 September 2020|doi-access=free |bibcode=2009CBio...19..915A }}</ref>

In mathematical models of the networks linking different plants and their many pollinators,<ref>{{cite journal | last1 = Bascompte | first1 = J. | last2 = Jordano | first2 = P. | last3 = Melián | first3 = C. J. | last4 = Olesen | first4 = J. M. | year = 2003 | title = The nested assembly of plant–animal mutualistic networks | journal = Proceedings of the National Academy of Sciences | volume = 100 | issue = 16| pages = 9383–9387 | doi=10.1073/pnas.1633576100 | pmid=12881488 | pmc=170927| bibcode = 2003PNAS..100.9383B | doi-access = free }}</ref> such a network can continue to function very well under increasingly harsh conditions, but when conditions become extremely harsh, the entire network fails simultaneously.<ref name=Lever_et_al>{{cite journal|last1=Lever |first1=J. J. |last2=Nes |first2=E. H. |last3=Scheffer |first3=M. |last4=Bascompte |first4 = J. |year = 2014 |title=The sudden collapse of pollinator communities |journal=Ecology Letters |volume=17 |issue=3 |pages=350–359 |doi=10.1111/ele.12236 |pmid=24386999 |bibcode=2014EcolL..17..350L |hdl= 10261/91808 |hdl-access=free}}</ref>

A 2021 study described as the "first long-term assessment of global bee decline", which analyzed [[Global Biodiversity Information Facility|GBIF]]-data of over a century, found that [[biodiversity|the number of bee species]] declined steeply worldwide after the 1990s, shrinking by a quarter in 2006–2015 compared to before 1990.<ref>{{cite news |last1=Shah |first1=Karina |title=A quarter of all known bee species haven't been seen since the 1990s |url=https://www.newscientist.com/article/2265680-a-quarter-of-all-known-bee-species-havent-been-seen-since-the-1990s/ |access-date=11 February 2021 |work=New Scientist}}</ref><ref>{{cite journal |last1=Zattara |first1=Eduardo E. |last2=Aizen |first2=Marcelo A. |title=Worldwide occurrence records suggest a global decline in bee species richness |journal=One Earth |date=22 January 2021 |volume=4 |issue=1 |pages=114–123 |doi=10.1016/j.oneear.2020.12.005 |bibcode=2021OEart...4..114Z |language=English |issn=2590-3330|doi-access=free |hdl=11336/183742 |hdl-access=free }}</ref>