Diferencia entre revisiones de «Disminución de polinizadores»
Contenido eliminado Contenido añadido
m seguir ampliando |
|||
| Línea 10: | Línea 10: | ||
<!-- |
<!-- |
||
== Declinación == |
== Declinación == |
||
Pollinators |
Pollinators are declining globally in both abundance and diversity.<ref>{{cite journal|last= Dirzo|first= Rodolfo|author2= Hillary S. Young|author3= Mauro Galetti|author4= Gerardo Ceballos|author5= Nick J. B. Isaac|author6= Ben Collen|title= Defaunation in the Anthropocene |journal= [[Science (journal)|Science]]|date= 2014|doi= 10.1126/science.1251817|pmid= 25061202|volume= 345| issue=6195|pages= 401–406|url=http://www.uv.mx/personal/tcarmona/files/2010/08/Science-2014-Dirzo-401-6-2.pdf|accessdate= 16 de diciembre de 2016|bibcode= 2014Sci...345..401D}}</ref> Bees, in particular, are thought to be necessary for the fertilization of up to 90% of the world's 107 most important human food crops.<ref name="The Daily Telegraph">{{cite news|url=https://www.telegraph.co.uk/news/2017/10/20/keepers-warn-bee-mageddon-france-authorises-controversial-insecticide/|title=Keepers warn of 'bee-mageddon' after France authorises controversial insecticide |publisher=The Daily Telegraph|date=20 de octubre de 2017|newspaper=The Telegraph |last1=Samuel |first1=Henry }}</ref> |
||
The [[Colony collapse disorder|decline in bee numbers]] has attracted much public attention. Members of the British Beekeepers' Association have issued numerous warnings in the 21st century that the country's bees are in rapid decline.<ref>{{cite news|url=https://www.telegraph.co.uk/finance/comment/ambroseevans_pritchard/8306970/Einstein-was-right-honey-bee-collapse-threatens-global-food-security.html|title=Einstein was right - honey bee collapse threatens global food security|newspaper=The Daily Telegraph|date=6 de febrero de 2011|last1=Evans-Pritchard|first1=Ambrose}}</ref><ref>{{cite news|url=https://www.telegraph.co.uk/news/uknews/1547243/Flowers-and-fruit-crops-facing-disaster-as-disease-kills-off-bees.html|title=Flowers and fruit crops facing disaster as disease kills off bees|newspaper=The Daily Telegraph|date=1 de abril de 2007|last1=Copping|first1=Jasper}}</ref> Writing in 2013, Elizabeth Grossman noted that 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 de abril de 2013}}</ref> In France, the [[honey]] harvest for 2017 has been estimated at around 10,000 tons, representing a decline of two-thirds against the average annual harvest during the 1990s.<ref name="The Daily Telegraph"/> |
|||
A 2017 study led by [[Radboud University Nijmegen|Radboud University's]] Hans de Kroon, using 1,500 samples from 63 sites, indicated that the biomass of insect life in Germany had declined by three-quarters in the previous 25 years. Participating researcher Dave Goulson of [[Sussex University]] stated that their study suggested that humans are making large parts of the planet uninhabitable for wildlife. Goulson characterized the situation as an approaching "ecological Armageddon", adding that "if we lose the insects then everything is going to collapse". Lynn Dicks at the [[University of East Anglia]] in 2017 estimated the rate of decline in flying insect biomass at roughly 6% a year.<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 de octubre de 2017|last1=Editor|first1=Damian Carrington Environment}}</ref> The decline has been termed by [[entomologists]] as the [[windshield phenomenon]], since it is associated with anecdotal reports that far fewer insects end up on car windshields now than a few decades ago. |
A 2017 study led by [[Radboud University Nijmegen|Radboud University's]] Hans de Kroon, using 1,500 samples from 63 sites, indicated that the biomass of insect life in Germany had declined by three-quarters in the previous 25 years. Participating researcher Dave Goulson of [[Sussex University]] stated that their study suggested that humans are making large parts of the planet uninhabitable for wildlife. Goulson characterized the situation as an approaching "ecological Armageddon", adding that "if we lose the insects then everything is going to collapse". Lynn Dicks at the [[University of East Anglia]] in 2017 estimated the rate of decline in flying insect biomass at roughly 6% a year.<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 de octubre de 2017|last1=Editor|first1=Damian Carrington Environment}}</ref> The decline has been termed by [[entomologists]] as the [[windshield phenomenon]], since it is associated with anecdotal reports that far fewer insects end up on car windshields now than a few decades ago. |
||
== Posibles causas == |
|||
Entre las posibles causas se cuentan el uso de [[plaguicida]]s, enfermedades y plagas, [[destrucción de hábitat]], [[contaminación atmosférica]], cambios climáticos, los efectos de monocultivos y competencia interespecífica entre especies nativas e introducidas.<ref>{{Cite book|url=https://www.nap.edu/read/11761/chapter/5|title=3 Causes of Pollinator Declines and Potential Threats {{!}} Status of Pollinators in North America {{!}} The National Academies Press|language=en|doi=10.17226/11761|year=2007|isbn=978-0-309-10289-6|last1=Council|first1=National Research|last2=Studies|first2=Division on Earth Life|last3=Resources|first3=Board on Agriculture Natural|last4=Sciences|first4=Board on Life|last5=America|first5=Committee on the Status of Pollinators in North}}</ref><ref>{{Cite web|url=http://ento.psu.edu/research/labs/john-tooker/news/2014/how-do-monocultures-influence-bee-health|title=How do monocultures influence bee health? (John Tooker Lab)|website=John Tooker Lab (Penn State University)|language=en-us|access-date=2017-11-30}}</ref><ref>{{Cite journal|last=Thomson|first=Diane M.|date=2016-10-01|title=Local bumble bee decline linked to recovery of honey bees, drought effects on floral resources|journal=Ecology Letters|language=en|volume=19|issue=10|pages=1247–1255|doi=10.1111/ele.12659|pmid=27539950|issn=1461-0248|url=https://semanticscholar.org/paper/1ee72d3596df5fba5ea7dfe113ec146b64e999eb}}</ref> |
|||
=== Plaguicidas === |
|||
La investigación ha relacionado la exposición a los insecticidas [[neonicotinoide]]s con una disminución de la salud de las abejas.<ref name=Henry>{{cite journal|last=Henry|first=Mickaël|author2=Maxime Béguin, Fabrice Requier, Orianne Rollin, Jean-François Odoux, Pierrick Aupinel, Jean Aptel, Sylvie Tchamitchian, and Axel Decourtye|title=A Common Pesticide Decreases Foraging Success and Survival in Honey Bees|journal=Science|date=April 20, 2012|issue=6076|pages=348–350|doi=10.1126/science.1215039 |volume=336|pmid=22461498|bibcode=2012Sci...336..348H|url=https://semanticscholar.org/paper/68547638135851ff07f0316d7e81dd3e20a933c3}}</ref><ref name=Whitehorn>{{cite journal|last= Whitehorn|first=Penelope|author2=Dave Goulson|title=Neonicotinoid Pesticide Reduces Bumble Bee Colony Growth and Queen Production|journal=Science|volume=336|date=April 2012|issue=6076|pages=351–352|doi=10.1126/science.1215025 |authorlink2=Dave Goulson|pmid=22461500|bibcode=2012Sci...336..351W|url=https://semanticscholar.org/paper/05951cd082dbebde39c56d04c13756b6ba32ea28}}</ref> Los plaguicidas interfieren con el funcionamiento del cerebro de las abejas,<ref name=Henry/> afectan su capacidad de navegación. Impiden que los abejorros coleccionen suficiente alimento para producir nuevas reinas.<ref name=Whitehorn/> |
|||
Los neonicotinoides son de alta toxicidad para una amplia variedad de insectos, incluyendo abejas domésticas y otros polinizadores.<ref>{{cite web|last=Feldman|first=Jay|title=Protecting Pollinators: Stopping the Demise of Bees|url=http://www.beyondpesticides.org/pollinators/documents/protectingpollinators.pdf|work=Pesticides and You|publisher=Beyond Pesticides}}</ref> Las plantas los incorporan en su sistema vascular y los expresan en el polen y néctar que constituyen el alimento de las abejas. Son sumamente peligrosos porque además de su toxicidad aguda en altas dosis, también tienen efectos subletales más sutiles cuando los insectos son expuestos a dosis bajas crónicas, como ocurre cuando recogen polen y néctar, así como el polvillo flotando en el aire después de una fumigación de plantas o de las semillas que han sido bañadas en imidacloprid. Estos efectos causan serios problemas para abejas individuales y para la colonia en general, alterando la movilidad, forrajeo, comunicación, memoria, etc.<ref>{{Cite web|url=http://www.muglacongress.org/eng/?page=invitation_apimondia_president|title=Invitation Letter of Apimondia President|last=McCabe|first=Philip|date=|website=International Mugla Beekeeping & Pine Honey Congress|access-date=}}</ref> |
|||
A French 2012 study of ''[[Apis mellifera]]'' (western honey bee or European honey bee)<ref name="French_2012">{{cite journal |journal=Science |date=20 April 2012 |volume=336 |number=6079 |pages=348–350 |doi=10.1126/science.1215039 |pmid=22461498 |title=A Common Pesticide Decreases Foraging Success and Survival in Honey Bees |first1=Mickaël |last1=Henry |first2=Maxime |last2=Béguin |first3=Fabrice |last3=Requier |first4=Orianne |last4=Rollin |first5=Jean-François |last5=Odoux |first6=Pierrick |last6=Aupine |first7=Jean |last7=Aptel1 |first8=Sylvie |last8=Tchamitchian |first9=Axel |last9=Decourtye |accessdate=4 October 2014 |url=http://sciences.blogs.liberation.fr/files/abeilles-pesti-2.pdf |url-status=dead |archiveurl=https://web.archive.org/web/20160304003456/http://sciences.blogs.liberation.fr/files/abeilles-pesti-2.pdf |archivedate=4 March 2016 |bibcode=2012Sci...336..348H }}</ref> that focused on the neonicotinoid pesticide [[thiamethoxam]], which is metabolized by bees into [[clothianidin]], a pesticide cited in legal action, tested the hypothesis that a sublethal exposure to a neonicotinoid indirectly increases hive death rate through homing failure in foraging honey bees. When exposed to sublethal doses of thiamethoxam, at levels present in the environment, honey bees were less likely to return to the hive after foraging than control bees that were tracked with radio-frequency identification (RFID) tagging technology, but not intentionally dosed with pesticides. Higher risks are observed when the homing task is more challenging. The survival rate is even lower when exposed bees are placed in foraging areas with which they are less familiar.<ref name="French_2012"/> |
|||
In their 2014 study of ''[[Bombus terrestris]]'' (buff-tailed bumblebee or large earth bumblebee), researchers tracked bees using RFID tagging technology, and found that a sublethal exposure to either [[imidacloprid]] (a neonicotinoid) and/or a [[pyrethroid]] (?-[[cyhalothrin]]) over a four-week period caused impairment of the bumblebee's ability to [[forage]].<ref name="Gill_Raine_2014">{{cite journal |journal=Functional Ecology |volume=28 |issue=6 |pages=1459–1471 |title=Chronic impairment of bumblebee natural foraging behaviour induced by sublethal pesticide exposure |first1=Richard J. |last1=Gill |first2=Nigel E. |last2=Raine |date=7 July 2014 |doi=10.1111/1365-2435.12292 |url=https://semanticscholar.org/paper/359aa374925b662c63a829cd08e555394154dd62 }}</ref> |
|||
[[Imidacloprid effects on bees]] were examined by researchers exposing colonies of bumblebees to levels of imidacloprid that are realistic in the natural environment, then allowed them to develop under field conditions. Treated colonies had a significantly reduced growth rate and suffered an 85% reduction in production of new queens compared to unexposed control colonies. The study shows that [[bumblebee]]s, which are wild pollinators, are suffering similar impacts of pesticide exposure to "managed" honey bees. Wild pollinators provide [[ecosystem services]] both in agriculture and to a wide range of wild plants that could not survive without insect pollination.<ref name=Whitehorn/> |
|||
In March, 2012, commercial beekeepers and environmental organizations filed an emergency legal petition with the [[U.S. Environmental Protection Agency]] (EPA) to suspend use of clothianidin, urging the agency to adopt safeguards. The legal petition, supported by over one million citizen petition signatures, targets the pesticide for its harmful impacts on honey bees. The petition points to the fact that the EPA failed to follow its own regulations. EPA granted a conditional, or temporary, registration of clothianidin in 2003 without a field study establishing that the pesticide would have no "unreasonable adverse effects" on pollinators. The conditional registration was contingent upon the submission of an acceptable field study, but this requirement has not been met. EPA continues to allow the use of clothianidin 9 years after acknowledging that it had an insufficient legal basis for initially allowing its use. Additionally, the product labels on pesticides containing clothianidin are inadequate to prevent excessive damage to nontarget organisms, which is a violation of the requirements for using a pesticide and further warrants removing all such mislabeled pesticides from use.<ref name=":0" /> |
|||
The disappearance of honeybees was documented in the 2009 film ''[[Vanishing of the Bees]]'' by George Langworthy and [[Maryam Henein]].<ref>{{cite news|last1=Bradshaw|first1=Peter|title=Vanishing of the Bees|url=https://www.theguardian.com/film/2009/oct/09/vanishing-of-the-bees-review|newspaper=The Guardian|accessdate=22 June 2015|date=9 October 2009}}</ref> |
|||
=== Transferencia de parásitos y patógenos === |
|||
Increased international commerce has moved [[diseases of the honey bee]] such as American foulbrood and chalkbrood, and parasites such as [[varroa]] [[mite]]s,<ref>Gill, Victoria (7 June 2012) [https://www.bbc.co.uk/nature/18339797 Honeybee virus: Varroa mite spreads lethal disease] BBC Nature News, Retrieved 11 June 2012</ref> [[acarina]] mites, and the small African hive beetle to new areas of the world, causing much loss of bees in the areas where they do not have much resistance to these pests. [[Solenopsis invicta|Imported fire ants]] have decimated ground-nesting bees in wide areas of the southern US.<ref name=":0" /> |
|||
=== Pérdida de hábitat === |
|||
Bees and other pollinators face a higher risk of extinction due to loss of habitat and access to natural food sources. The global dependency on livestock and agriculture has rendered no less than 50% of the earth's landmass uninhabitable for bees. The agricultural practice of planting one crop (monoculture) in a given area year after year leads to extreme malnourishment. Regardless if the planted crop does flower and provide food for the bee, the bee will still be malnourished because a single plant cannot meet its nutrient requirements. Furthermore, the crops needed to support livestock (primarily cattle) tend to be grains, which do not provide nectar.<ref>{{cite journal | last1 = Lebuhn | first1 = Gretchen |display-authors=etal | year = 2013 | title = Detecting Insect Pollinator Declines on Regional and Global Scales | url = https://semanticscholar.org/paper/183d745279cf7aa9f89bd033dff519cbbc2fea48| journal = Conservation Biology | volume = 27 | issue = 1| pages = 113–120 | doi=10.1111/j.1523-1739.2012.01962.x| pmid = 23240651 }}</ref> Artificial water bodies, open urban areas, large industrial facilities including heavy industry, railways and associated installations, buildings and installations with a sociocultural purpose, camping, sports, playgrounds, golf courts, oilseed crops other than oilseed rape such as sunflower or linseed, some spring cereals and former forest clearcuts or windthrows were frequently associated with high honey bee colony losses.<ref name=Clermont>{{cite journal |author1=Clermont, A.. |author2=Eickermann, M. |author3=Kraus, F. |author4=Hoffmann, L.|author5=Beyer, M.|year=2015 |title=Correlations between land covers and honey bee colony losses in a country with industrialized and rural regions |journal=Science of the Total Environment |volume=532 |pages=1–13 |doi=10.1016/j.scitotenv.2015.05.128|pmid=26057621 |bibcode=2015ScTEn.532....1C }}</ref> |
|||
Researchers at UC Berkeley and UC Davis have found that if farms were to plant and maintain wildflower borders around their crop fields, they would see an eight-fold increase in bee abundance compared to farms without wildflower habitat. While most farms use managed bees, from either their own hives or rented, to pollinate their crops, wild bees can meet 100% of their pollination needs so long as they are plentiful. By maintaining wildflowers near their crops, farms would be able to resource natural pollination. The act of providing pollinators with more nutrient rich habitats, while having the benefit of "free" crop pollination, is a simple way to aid in the reduction of pollinator decline.<ref>[http://icpbees.org/wp-content/uploads/2014/05/CA-Row-Crops-Habitat-Guide-FINAL-1.pdf May, E.; Ward, K.; Williams, N; Ullmann, K; Isaacs, R; Kay Cruz, J.; Bolte, K.; Foltz Jorda, S.; Hopwood, J.; Vaughan, M.. (2017). "Establishing Wildflower Habitat to Support Pollinators of California Row Crops". The University of California, Davis and The Xerces Society of Invertebrate Conservation. 2]</ref> |
|||
=== Contaminación atmosférica === |
|||
Researchers at the [[University of Virginia]] have discovered that [[air pollution]] from [[automobile]]s and [[power plant]]s has been inhibiting the ability of pollinators such as bees and [[butterfly|butterflies]] to find the [[fragrance]]s of [[flower]]s. [[Pollutant]]s such as [[ozone]], [[hydroxyl]], and [[nitrate]] [[radical (chemistry)|radical]]s bond quickly with volatile scent molecules of flowers, which consequently travel shorter distances intact. There results a [[vicious cycle]] in which pollinators travel increasingly longer distances to find flowers providing them nectar, and flowers receive inadequate pollination to reproduce and diversify.<ref>{{cite web|url=http://www.eurekalert.org/pub_releases/2008-04/uov-ffd041008.php|title=Flowers' fragrance diminished by air pollution, University of Virginia study indicates|date=10 April 2008|work=EurekAlert!}}</ref> |
|||
=== Cambios de comportamiento estacional debidos a calentamiento global === |
|||
In 2014, the [[Intergovernmental Panel on Climate Change]] reported that bees, butterflies, and other pollinators faced increased risk of extinction because of [[global warming]] due to alterations in the seasonal behaviour of species.<ref name= DailyTelegraph>Gosden Emily (29 March 2014) [https://www.telegraph.co.uk/earth/earthnews/10730667/Bees-and-the-crops-they-pollinate-are-at-risk-from-climate-change-IPCC-report-to-warn.html Bees and the crops they pollinate are at risk from climate change, IPCC report to warn] The Daily Telegraph, Retrieved 30 March 2014</ref> Climate change was causing bees to emerge at different times in the year when flowering plants were not available. |
|||
=== Luces artificiales nocturnas === |
|||
In June 2018, the ''Leibniz-Institute of Freshwater Ecology and Inland Fisheries'' [[:de:Leibniz-Institut für Gewässerökologie und Binnenfischerei|(de)]] released an article that discusses a possible link between the sharp decline in flying insects and high levels of [[light pollution]]. Many studies suggest that artificial light at night has negative impacts on insects, and scientists should therefore pay greater attention to this factor when exploring the causes of [[insect population decline]].<ref>[http://www.igb-berlin.de/en/news/light-pollution-reason-insect-decline Light pollution a reason for insect decline!?] press release igb-berlin.de, 19 June 2018</ref><ref>[https://www.photonics.com/Articles/Artificial_Lighting_at_Night_Could_be_Cause_of/a63612 Artificial Lighting at Night Could be Cause of Declining Insect Populations] photonics.com, 29 June 2018</ref><ref>[https://dspace.library.uu.nl/handle/1874/319074 Insects, bats and artificial light at night: Measures to reduce the negative effects of light pollution] in: dspace.library.uu.nl, retrieved 28 July 2018, author: Claudia Rieswijk (2015), Faculty of Science Theses (Master thesis), [[Utrecht university]]</ref><ref>Travis Longcore & Catherine Rich (2004): Ecological light pollution. Frontiers in Ecology and the Environment 2(4): 191–198. {{DOI|10.1890/1540-9295(2004)002[0191:ELP]2.0.CO;2}}</ref> |
|||
--> |
--> |
||
Revisión del 21:53 9 feb 2020
.jpg)
La declinación de polinizadores se refiere a la disminución en la abundancia y variedad de los insectos y otros animales que realizan la polinización de las plantas. Esto tiene lugar en muchos ecosistemas de todo el mundo, comenzando en el siglo XX y que continúa en el comienzo del siglo XXI.[1][2]
En los Estados Unidos, el gobierno ha declarado que las abejas están muriendo en cantidades insostenibles. En este país las abejas contribuyen quince mil millones de dólares en cosechas. Sin polinizadores, la agricultura sufriría un desastre. Un tercio de los alimentos mundiales dependen de productos polinizados por insectos y otros animales.[3]
Los polinizadores participan en la reproducción sexual de muchas plantas realizando polinización cruzada, esencial para algunas especies y un factor importante de la diversidad genética. Como las plantas son los productores primarios que proporcionan alimentación al reino animal, la falta de polinizadores sería devastadora par los animales.
La magnitud del problema es motivo de intenso debate; parece que la mayoría, si bien no todos, los datos provienen de abejas domésticas y abejorros de Europa y Estados Unidos. Algunas especies andan mejor que otras, algunas se mantienen estables y aun otras están aumentando, tales como las colmenas de abejas en ciertas regiones del mundo. Pero, en general, hay «disminuciones significativas en abundancia y diversidad a diferentes escalas espaciales múltiples en muchas regiones».[4]
Las posibles explicaciones de la pérdida de polinizadores incluyen el uso de plaguicidas, enfermedades, pérdida de hábitat y competencia con especies invasoras.
Véase también
- Abejas y elementos tóxicos
- Biodiversidad de los insectos
- Disminución de las poblaciones de insectos
- Efectos del imidacloprid en las abejas
Referencias
- ↑ Kluser, S. and Peduzzi, P. (2007) "Global pollinator decline: a literature review" UNEP/GRID – Europe.
- ↑ Dirzo, Rodolfo; Hillary S. Young; Mauro Galetti; Gerardo Ceballos; Nick J. B. Isaac; Ben Collen (2014). «Defaunation in the Anthropocene». Science 345 (6195): 401-406. Bibcode:2014Sci...345..401D. PMID 25061202. doi:10.1126/science.1251817. Consultado el 16 de diciembre de 2016.
- ↑ Goulson, David (March 2013). «Give bees a chance». New Scientist 217 (2910): 29. ISSN 0262-4079. doi:10.1016/s0262-4079(13)60812-x.
- ↑ «How good is the evidence base for pollinator declines? A comment on the recent Ghazoul and Goulson Science correspondence». Jeff Ollerton's Biodiversity Blog (en inglés). 3 de junio de 2015. Consultado el 19 de mayo de 2019.
| Control de autoridades |
|
|---|
Datos: Q7225689