Month: februar 2015
Population control
Most of the environmental problems nowadays like climate change and biodiversity loss, have one thing in common, human overpopulation. According to United Nations the world populations will reach around 9 billion people in 2050 with their ever demanding need for food and fresh water [1], prospects are not looking good. Drastic measures need to take place and in the world we live in nowadays it looks like that is not going to happen. On the climate convention in 2009 in Copenhagen it was decided that temperatures should not raise any more than 2 degrees Celsius without any nations that really wanted to give in [1]. Instead of countries trying to bring down their CO2 emissions they’ve resulted in a global trade of ‘fresh air’ . Belgium for example has spent around 194 million euros on fresh air in order to meet the Kyoto norms [2]. Public awareness is simply too low for governments to take any drastic measures, in the Netherlands for example the green minded party GroenLinks, has since foundation in 1990 never been part of the government and at the last elections they only received 2.3 percent of the overall votes [3].
Democracy seems a great way to govern a country where everybody has an equal vote, but when it comes to affairs that are greater than the wellbeing of a nations inhabitants it seems like it doesn’t work. Every party that has some drastic ideas concerning the environmental preservation, doesn’t get a place in the government because people mostly don’t care, vote in regard to their own wellbeing and they cannot directly perceive the measures a party takes because it takes a long time to notice any environmental change, let alone some ideas about population control which has been established in China a communistic country [4].
Because let’s face it the best way to preserve our environment and wildlife is not by trying to lower our ecological footprint but to control human population growth and preferably make it decline but since that is not a priority in most western countries further boundaries need to be established.
References
1. www.un.org
2. http://www.hln.be België koopt «schone lucht» vooral in het buitenland. 20/11/2013
3. www.parlement.com GroenLinks
4. http://www.telegraph.co.uk/ What is China’s one-child policy? 30/9/2014
Alien species dilemma
Non-native species that have been introduced by humans over the past decades have been known to cause a lot of trouble. For example the introduction of rabbits in Australia who were introduced for the hunting sport but quickly caused the most rapid invasion of animals ever recorded(Animal Control Technologies Australia), or the Nile perch that was introduced in lake Victoria and completely disrupted the lakes ecosystem (Ogutu-ohwayo 1990). All for various reasons, whether it is for the hunting or fishing sport, as with the rabbits and some fish species, or to kill a plague in an area, after which the introduced species handled themselves better than expected (Philips & Shine 2006). Internationalisation doesn’t help much either. Almost every kind of species which is farmed or bred can be spread almost all around the world and are being introduced into an area in which it is not native, where escapees or pollen can cause a lot of trouble on both economical and environmental scales. Transport these enables humans to travel to the other side of world while we unknowingly spread all kinds of plant seeds, spores or even eggs from insects for example (Mack & Lonsdale 2001, Keth 1999). All in all humans have become a greater form of global dispersal rather than mother nature itself we have given the non-native or alien species a very bad reputation.
But we should also consider this, it is by all means clear that humans have had a bigger impact on the global ecosystem than all directly or indirectly introduced species combined, mainly by changing the native species’ original habitat in all kinds of ways (Davis 2011). It is therefore not remarkable that non-native species do so well since the original habitat has shifted to a state not suitable anymore for some native species, and because a lot of non-native species are either intentionally or unintentionally introduced, there is bound to be one or more species among them that are able to adapt to the new environment (Davis 2011). Since we might be too late to restore habitats in their original state (and yet we still try to), an article by Mark Davis argues that rather than trying to get rid of non-native species we should embrace them and maybe use them to our benefits. The article mentions for example that tamarisks, which have been introduced from Europe and Asia to America, fulfil in the habitat the same role as the species it outcompeted in the first place.
Non-native species will be introduced everywhere around the world whether we want it or not. Instead of preventing introductions we should maybe do more research in using alien species to our advantage. We changed to world in major way ourselves, so we should just deal with the consequences.
References
Davis, M. A., Chew, M. K., Hobbs, R. J., Lugo, A. E., Ewel, J. J., Vermeij, G. J., Brwon, J. H., Rosenzweig, M. L., Gardener, M. R., Carroll, S. P., Thompson, K., Pickett, S. T. A., Stromberg, J. C., Del Tredici, P., Suding, K. N., Ehrenfeld, J. G., Grime, J. P., Mascaro, J., Briggs J. C. 2011. Don’t judge species on their origins. Nature 474, 153-154, 09 June 2011.
Keth, A.C. 1999. Three Incidents of Human Myiasis by Rodent Cuterebra (Diptera: Cuterebridae) Larvae in a Localized Region of Western Pennsylvania. Journal of Medical Entomology, Volume 36, Issue 6, 1 November 1999.
Mack, R. N., Lonasdale, W. M. 2001. Humans as Global Plant Dispersers: Getting More Than We Bargained For. Bioscience 51 (2): 95-102, 2001)
Ogutu-Ohwayo, R. 1990. The decline of the native fishes of lakes Victoria and Kyoga (East Africa) and the impact of the introduced species, especially the Nile perch, Lates niloticus, and the Nile tilapia, Oreochromis niloticus*. Evironmental Biology of Fishes 27: 81-96, 1990.
Philips, B. L., Shine, R. 2006. An invasive species induces rapid adaptive change in a native predator: cane toads and black snakes in Australia. Proc. R. Soc. B 22 June 2006 vol. 273 no. 1593 1545-1550
http://www.animalcontrol.com.au/rabbit.htm
Global change affecting trophic interactions between plants and other interactions
Climate change influences trophic interactions. Drivers of global change (e.g. increased CO2 or nitrogen levels or invasions) can alter competitive interactions between different trophic levels. These drivers can perform effects on intensity of pathogen infection, herbivory, predation or they can be helpful for new invasive species (1).
Truth is that global change drivers could have some positive impacts on nature f.e. risen CO2 or N levels can have positive effects for plant growth (2) or nectar production (3), but negative effects are probably more frequent. Example of negative effect could be competition of pollinator between native and alien plant (4, 5) or shift in timing of plant activities (in their phenology; 6,7). In first case native plant could not be pollinated because pollinator will prefer alien plant and in second case specific pollinator and pollinated plant have “bad timing” because pollinator will not be present at the time when plant is flowering. For pollination mutualisms could be also destructive land use and habitat fragmentation which can easily affect plants through loss of pollinator diversity (8).
Alien plant species could also alter fungal and microbial communities in soil (9) which could have an effect on N and P deposition or they can just overgrow native species because of lack of natural predators.
Global change drivers could also favour some species, for example C4 plants could grow in higher temperatures (9) which can then be more competetively successful, and they can also affect plant-herbivory interactions for example when CO2 levels are increased, herbivore activity often decline (11). Alien plants can also support herbivores which have then higher reproductive capacity and they can more readily attack native species (12). Invasions of plants into new localities could alter either belowground biota, but in longer term also another (native) plants, like Myrica faya in Hawaii where this plant caused more than fourfold increase of soil nitrogen input and subsequent increase of ecosystem productivity (13).
Examples mentioned above shows either positive but also negative impacts of global change drivers on trophic interactions. Plant abundance is affected by both belowground and aboveground trophic level interactions. These species interactions will alter during climate change, and this will result that some species became rare or even extinct and some will became more abundant.
1 Tylianakis, J. M., Didham, R. K., Bascompte, J., & Wardle, D. A. (2008). Global change and species interactions in terrestrial ecosystems. Ecology letters, 11(12), 1351-1363.
2 Muñoz, A., Celedon-Neghme, C., Cavieres, L.A. & Arroyo, M.T.K. (2005). Bottom-up effects of nutrient availability on flower production, pollinator visitation, and seed output in a high-Andean shrub. Oecologia, 143, 126–135.
3 Davis, M.A. (2003b). Biotic globalization: does competition from introduced species threaten biodiversity? Bioscience, 53, 481–489.
4 Lopezaraiza-Mikel, M., Hayes, R., Whalley, M. & Memmott, J. (2007). The impact of an alien plant on a native plant–pollinator network: an experimental approach. Ecol. Lett., 10, 539–550.
5 Aizen, M.A., Morales, C.L. & Morales, J.M. (2008). Invasive mutualists erode native pollination webs. PLoS Biol., 6, e31.
6 Memmott, J., Craze, P.G., Waser, N.M. & Price, M.V. (2007). Global warming and the disruption of plant–pollinator interactions. Ecol. Lett., 10, 710–717
7 Cleland, E. E., Chuine, I., Menzel, A., Mooney, H. A., & Schwartz, M. D. (2007). Shifting plant phenology in response to global change. Trends in ecology & evolution, 22(7), 357-365.
8 Chacoff, N.P. & Aizen, M.A. (2006). Edge effects on flower-visiting insects in grapefruit plantations bordering premontane subtropical forest. J. Appl. Ecol., 43, 18–27.
9 Mummey, D.L. & Rillig, M.C. (2006). The invasive plant species Centaurea maculosa alters arbuscular mycorrhizal fungal communities in the field. Plant Soil, 288, 81–90.
10 Pringle, A., Adams, R. I., Cross, H. B., & Bruns, T. D. (2009). The ectomycorrhizal fungus Amanita phalloides was introduced and is expanding its range on the west coast of North America. Molecular Ecology, 18(5), 817-833.
11 Bezemer, T.M. & Jones, T.H. (1998). Plant–insect herbivore interactions in elevated atmospheric CO2: quantitative analyses and guild effects. Oikos, 82, 212–222.
12 Rand, T.A. & Louda, S.M. (2004). Exotic weed invasion increases the susceptibility of native plants to attack by a biocontrol herbivore.Ecology, 85, 1548–1554
13 P. M. Vitousek, L. R. Walker, Ecol. Monogr. 59, 24(1989). M. J. Swift, O. W. Heal, J. M. Anderson, Decompositio
Tomáš Figura
Are European orchids threatened by anorganic nitrogen -one of the main drivers of global change?
fig.1 oligotrophic canopy of P.albida, in albania distr. Tropoje
fig.2 oligotrophic canopy of P.albida with local sheppard in Albania, Tropoje, 2nd Photo by Jaroslav Vojta
A quarter of species of the second world biggest plant family – Orchidaceae is at risk of extinction. This could be caused due to smuggling, habitat loss and impact of climate change (1). Orchids have specific physiology, and many researchers have been studying them in last decades either due to their commercial production, their loss from nature or their specific biology. One of their specific trait is that they have minute seeds, almost without nutrients, and they germinate only under specific conditions. Many species are cultivated for commercial or research purposes but some species have never been germinated in conditions in vitro (or in situ), and we do not know why they are not growing. This was the case of Pseudorchis albida, which is and not just according to our study (2), extremely strongly inhibited by inorganic nitrogen. P.albida will not grow when there is even very low concentration of inorganic nitrogen in substrate (2 mg of No3 per liter of growing media).
In Europe, concentrations of anorganic nitrate in soil are between 0.1 – 100 mg/l NO3 (3, 4, 5), and globally N levels are rising. When we look at hygienic limit for concentration of nitrates in tap water in EU, it is 50 mg/l, and this concentration is sometimes reached, or even exceeded. The real data shows e.g. 37,6 and 19,2 mg per liter for Prague (6). But when we look into other sources (7) we can see that the concentration of nitrates in most European water sources is already above 100 mg/l. According to this we can conclude that this species will not grow when watered with tap water from almost all European water sources, because just concentration of 50 mg/l of nitrates inhibits germination 44 times and when sowed on concentration 100 mg/l this species is not growing at all ! (2)
This specific inhibition on seed germination and subsequent growth is not specific just for Pseudorchis albida, but we found similar extremely strong inhibition also on many other orchid species, which are evolutionary or ecologically common to Pseudorchis albida and also some effect on species Orthilia secunda, which belongs to Ericaceae family (yet unpublished data).
We can just speculate why those plants have this inhibition or where is the evolutionary purpose of this inhibitory effect; it could be some mechanism which is protecting the seed from germinating on places which are rich on inorganic nitrogen, and therefore place like this could be easily inhabited by expansive or/and ruderal species, and subsequently that place would not be suitable for growing of an orchid. However it is obvious that many orchid species are disappearing from nature and it looks like that some of them probably just due to the nitrogen – one of the main drivers of global change.
Important information which we should keep in our minds is that because of increased use of fertilizers, there is very steep increase of nitrogen levels in nature in last years (f.e. 8) and one of bad consequences of this could be potential loss of some orchids from nature. This can happen really quickly and even before we find out how to save those species at least using in vitro/in situ cultivation.
fig.3.: mycoheterotrophic protocorm of P. albida
1 Swarts, N.D., Dixon, K.W.: Terrestrial orchid conservation in the age of extinction. – Ann. Bot. 104: 543-556, 2009.
2 Ponert, J., Figura, T., Vosolsobe, S., Lipavska, H., Vohnik, M., & Jersakova, J. (2013). Asymbiotic germination of mature seeds and protocorm development of Pseudorchis albida (Orchidaceae) are inhibited by nitrates even at extremely low concentrations. Botany
3 Callesen, I., Raulund-Rasmussen, K., Gundersen, P., and Stryhn, H. 1999. Nitrate
concentrations in soil solutions below Danish forests. For. Ecol. Manage.
114(1): 71–82.
4 Fetter, J.C., Brown, R.N., Görres, J.H., Lee, C., and Amador, J.A. 2012. Nitrate and
phosphate leaching under turfgrass fertilized with a squid-based organic
fertilizer. Water Air Soil Pollut. 223(4)
5 Pedersen, A., Petersen, B.M., Eriksen, J., Hansen, S., and Jensen, L.S. 2007. A
model simulation analysis of soil nitrate concentrations — Does soil organic
matter pool structure or catch crop growth parameters matter most? Ecol.
Modell. 205(1-2)
6 http://www.pvk.cz/res/data/001/000205.pdf?seek=2
7 Commision of the europaean communities (2007):Comission staff working
dokument: Accompanying document to the Report to the commission to the council and the europaean parliament on implementation of Council Directive 91/676/EEC concerning the protection of waters against pollution caused by nitrates from agricultural sources for the period 2000-2003 COM (2007) 120 final
8 Tilman, D., Fargione, J., Wolff, B., D’Antonio, C., Dobson, A., Howarth, R., … & Swackhamer, D. (2001). Forecasting agriculturally driven global environmental change. Science, 292(5515), 281-284.
Tomáš Figura
How does global change affect trophic interactions between plants and pollinators?
Trophic interactions are complex
A basic principle of trophic interactions is that all species are affected by other species, in one way or another. Trophic interactions are complex and are therefore difficult to study. In high-school biology books, examples of trophic interactions are simplified, and often limited to two-trophic levels. For instance, hawk eats mice, or lynx eats hare. Many would be surprised that the abundance of fish in a mountain lake could affect the abundance of pollinators, that in turn affect plant crops. A decline in the abundance of fish in the lake could lead to more larval dragonfly, and dragonflies predate on pollinators.These multi-trophic interactions are clearly challenging to study. This is one example that illustrates why conserving biodiversity is important, and something everyone should be concerned with. Trophic interactions are so complex, and local extinction or decline in abundance of one species can have unknown consequences.
Global changes affect plant-pollinator interactions
Pollination is a mutualistic interaction in which both the pollinator and the plant benefit from the interaction. The pollinator ensures seed-dispersal for the plant, and the plant provides the pollinator with nectar. In other words, pollinators play an important role in ecosystem functions. In addition, pollinators are providers of ecosystem services important to humanity.
The decline in pollinator populations and species has been a hot topic. In my opinion this is largely because of convincing numbers that illustrate the great economical value of pollinators pollinating crops and providing food for humanity. The rapidly changing species distribution of pollinators is concerning. Current global changes impose several threats to pollinators, and there is no denying that human activity is largely to blame. Habitat change, invasive species and climate change have increased the risk of pollinator and plant species going extinct, locally or globally [1].
When speaking of global change in regards to ecology, one usually thinks of climate change. Climate change has been shown to affect phenological events, such as flowering in plants, and the first flight of pollinators [2].There is a tendency that pollinators start their activity earlier in the season than plants. This could cause a mismatch situation where pollinators start their activity before the plants are ready for them, and thereby limiting the opportunity for interaction between them [3].
Climate change may affect species directly, but also indirectly [2]. In addition, trophic partners can become disconnected because they may respond differently to global changes, such as climate change. The mismatch can be both spatial (distributional) and temporal (phenological) [2], however, there is much we do not know as the consequences of mismatches have not been thoroughly studied.
Hoverfly, a pollinator, aproaching a thistle head.
Photo: Lawrence Kirkendall
http://www.uib.no/en/rg/EECRG/55890/how-far-will-pollinator-go
Invasive species can disrupt existing plant-pollinator interactions
The introduction of new species can affect the trophic interactions. In fact, studies have shown that the presence of an invasive plant species can affect pollinators fidelity and preference to native plants [4]. This could affect the reproductive success of the native plant.It is difficult to predict the consequences. A case study indicated that pollinators will not necessarily prefer an invasive species that has a larger, showier floral display [4]. Another factor that must be taken into consideration is that the interactions can change over the course of an invasion.
Why should we bother?
First of all, biodiversity is in my opinion a good enough argument on its own. However, politicians are concerned with economics and numbers. Perhaps it is wise to focus on the arguments that will get their attention, and hopefully convince them to consider how their political decisions can affect biodiversity. Some might argue that focusing on ecosystem services rather than biodiversity being valuable in itself may lead to exploitation or ignoring conservation of species that are in danger of extinction, because they do not provide a significant ecosystem service. However, an important argument in my opinion is that we do not know enough about possible ecosystem services, therefore everyone should be interested in conserving biodiversity.
We may not be able to counteract global warming soon enough for the pollinators’ sake, but we can try to reduce the pressure on them. Habitat change has been declared as the greatest threat to biodiversity and the main reason why species go locally and globally extinct. Maybe this is where we should start.
References
2. Hegland, S. J., Nielsen, A., Lázaro, A., Bjerknes, A.-L. and Totland, Ø. (2009), How does climate warming affect plant-pollinator interactions?. Ecology Letters, 12: 184–195. doi: 10.1111/j.1461-0248.2008.01269.x
3. Memmott, J., Craze, P. G., Waser, N. M. and Price, M. V. (2007), Global warming and the disruption of plant–pollinator interactions. Ecology Letters, 10: 710–717. doi: 10.1111/j.1461-0248.2007.01061.x
4. King, V.M, Sargent, R.D., Presence of an invasive plant species alters pollinator visitation to a native, Accepted: 8 February 2012 Springer Science+Business Media B.V. 2012. Biol Invasions. doi: 10.1007/s10530-012-0191-3
Hvordan en stemme kan bli til flere.
Bilde fra: Silver Lane Studio, hentet fra : http://silverlanestudio.com/the-science-of-social-10-social-media-statistics-you-might-like-to-know/
Vi omgis av sosiale medier og nettaviser hver dag. Hverdagen vår styres i større eller mindre grad av slike medier, enten man vil det eller ei. Enten om det er indirekte gjennom venner eller direkte gjennom en tørst etter nyheter. Etterhvert som årene går har dette blitt enda mer tydelig hvordan sosiale medier har en innvirkning på menneskets hverdag. Store begivenheter som «Den arabiske våren» eller «Earth Hour» vil kanskje ikke vært mulig uten sosiale medier. WWFs Earth Hour 2014 hadde hele 1.2 milliarder tags på Twitter den 29 mars 2014 [1]. Dette vitner om at man på kort tid kan uttrykke seg og dele sine meninger til tusener av menneske. Via sosiale medier er det lett at man skaper meninger om en sak hos folk som tidligere ikke har meninger i saken. Siden dette spres ut til så mange på nettet, kan dette være med å spre budskap som opprinnelig er basert på misforstått eller gal kunnskap. Medier som Facebook, Twitter og Youtube har alle store brukergrupper som alle bidrar med deling av ytringer på nett.
De siste årene har det blitt mer og mer snakk om menneskeskapte klimaendringer. Klimaet er i stadig endring og klimaet blir varmere de siste tiårene. Saker om menneskeskapte klimaendringer har heller ikke sluppet unna sosiale medier. Både som klimablogger, nyhetssaker om klima og Twitter meldinger. I sosiale medier finner vi både saker om hvordan klimaet endrer seg på grunn av mennesker, og vi finner saker som sier at dette bare er ren fantasi. Alle disse sakene kan frembringe holdninger hos folk, og kan også skape et stort sprik mellom fakta og meninger. Spørsmålet «Kan sosiale medier redde planeten?» er stilt før [2]. Sosiale medier kan være med på å motivere folk til både handlinger og holdninger til de klimatiske endringen vi har observert de siste tiårene. Klart at sosiale medier kan være et viktige virkemidler i kampen for allmenn bevissthet, men da må også informasjonen tilrettelegges for allmennhetens kunnskapsnivå på en tydelig måte.
FNs klimapanel (IPCC) ble opprettet i 1988 med et formål å binde sammen eksisterende kunnskap om klima og klimatiske endringer. I rapportene sine har de konkludert med at klimaet er i endring og at dette er menneskepåvirket. IPCC har prøvd å få sin informasjon om klimaendringer ut til menigmann, men har kanskje dessverre ikke helt fått til. IPCC har en kommunikasjons strategi [3] som sier at de skal «kommunisere en klar og balansert informasjon…, uten at dette går på kompromiss med nøyaktigheten» [3]. Det sies også her at informasjonen skal formidles til menigmann, men de er ikke primærmålet for informasjonen. Alle strategiene er på plass, men det mangler en retning mot de nyere sosiale mediene. IPCC har hatt Twitter, Youtube og Facebook kontoer i flere år nå, men de sliter likevel med å nå ut til publikum. Kanalene til IPCC baser seg mer på en gammel «en til mange» kommunikasjon, og det er lite til ingen interaksjon med lesere og brukere av IPCC rapportene. Å forsømme slike viktige kommunikasjonskanaler kan gjøre at allmenheten mister både motivasjon angående tema og tillit til innehaverne.
Bilde fra: Knight Science Journalism at MIT, hentet fra: https://ksj.mit.edu/tracker/2013/09/global-warming-5th-ipcc-eve-news-stories/
På nett er det en rekke kanaler hvor klimaskeptikere kommer med sine meninger om klimaendringene. Det finnes nyhetssaker og innlegg om at det ikke eksisterer klimaendringer, eller at klimaendringer er naturlig og har ikke noe med mennesker å gjøre. Den sistnevnte meningen er den som er vanligst å finne i sosiale medier. Vi kan ta “The Corbett Report” som er en ukentlig podcast. Denne tar ikke hovedsakelig for seg klimaendringer, men har laget en lengre sak om IPCC kalt “The IPCC Exposed” [4]. Podkasten til “The Corbett Report” river i stykker IPCC sin rapport og argumenterer for at de observerte klimaendringene ikke er menneskelagt. I denne podkasten tar han for seg IPCC rapporten fra 2007 og det den sier om at mennesker er hovedårsaken til klimatisk oppvarming. Podkasten tar for seg påstander fra media om hvordan rapporten ikke kan holde mål, men er ikke det bare en side av saken? På samme måten er mye av meningene på nettet, ensidig og lite augmentativ. Samtidig har slike kilder til informasjon forstått det nye formatet på en bedre måte og dermed har mulighet til å formidle sine meninger enklere.
Det er viktig med en slik skepsis til forskningen, men det er likeså viktig at denne skepsisen er vitenskapelig begrunnet. Mye av debatten på sosiale medier om klimaforskning er ikke vitenskapelig begrunnet og kan heller ikke spores tilbake til kilder. Det skal også sies at sosiale medier som oftest brukes som en plass for tankeutspill og dermed ikke har høye krav til kildebruk. Det er derfor viktig i slike sammenhenger å være kritisk til både forskere og kritikere. Kommentarer som “Klimaendringer er laget av folk som hater kapitalister og USA” [5] er lite saklig og bør tas med en klype salt. Andre kommentarer igjen er så vitenskapelig at det er vanskelig å vite om innholdet i kommentarene er korrekt uten større kunnskaper om temaet.
Det er her organisasjoner som ICPP bør gå aktivt inn å høre på og diskutere med mannen i gaten, og ikke bare med andre forskere. Det er til syvende og sist flere menigmann enn forskere i verden. Det er viktig at det er en motpart til klimaskeptikere i debatten som foregår i sosiale medier. Jeg skal ikke si at denne motparten er helt manglende der ute, men den er ikke like pågående som klimaskeptikerne. I klimasammenheng ville det vært naturlig at ICPP tok en del i debatten som motpart til skeptikerne. Samtidig er det viktig at de holder budskapet på et nivå som allmenheten vil kunne enkelt forstå.
Det er blant klimaforskere 97% enighet om at klimaendringene en menneskestyrte [6]. Dette er ganske klart svar. Likevel virker det som om det er de som er skeptisk til menneskepåvirkede klimaendringer som skriker høyest. Hvorfor er det slik? Kan det være siden motparten i diskusjonen ikke i like stor grad benytter seg av sosiale medier? Det å forstå måten sosiale medier sprer budskap på er viktig får å få kunne gjøre menneskeskapte klimaendringer allment akseptert.
Det sier at man bare er maksimalt seks bekjentskapsledd unna hvem som helst på jorden. Så husk at det bare er maksimalt seks ledd fra deg og til de som avgjør klimatiltak [7]
Bilde hentet fra: The guardian url: http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/sep/07/social-media-event-97-hours-of-climate-experts
Kjetil Fossheim
Den globale matkrisen – hva kan vi gjøre?
Som enkeltperson er det ofte lett å si fra seg ansvaret når en hører om globale problemer som økende populasjonsvekst og matmangel. Verden er jo så stor så hvilken forskjell kan vel vi utgjøre? Det er viktig å huske at som forbrukere kan vi ha stor innflytelse, en innflytelse som strekker seg mye lenger enn middagsbordet.
I boka «Full Planet, Empty Plates» skriver Lester Brown at det er tre årsaker til at vi nå har en økende etterspørsel etter mat; populasjonsvekst, økende velstand og biobrensel.
Populasjonsvekst
Den stadig økende befolkningsveksten gjør at den globale etterspørsel etter mat bare vil vokse seg større og større. Fortsetter verdens befolkning å vokse i den hastigheten den har i dag er det beregnet at vi vil overstige 9 milliarder mennesker innen 2050. Bare i kveld vil det være 219,000 flere munner å mette rundt middagsbordet.
Økende velstand
Med økt velferd kommer større forbruk, da spesielt av prosessert mat, kjøtt, meieriprodukter, egg og fisk. En kan se på det som vi mennesker klatrer opp i næringskjeden. I vår del av verden så vi en slik utvikling da velstanden økte etter 2.verdenskrig. I dag er denne trenden tydelig i de nyere industrialiserte landene som for eksempel Kina, som har oversteget den tidligere verstingen USA i forbruket av kjøtt (se Figur 1).
Når forbruket av slike produkter øker får vi en indirekte økning korn og andre avlinger. For å beskrive dette kan vi sammenligne det årlige kornforbruket per person i India og USA; i India hvor det spises lite kjøtt er dette forbruket på 172kg, mens det i USA er 635 kg (hele 4/5 er indirekte i form av kjøtt, melk og egg). Økt forbruk av kjøtt har også ført til økt etterspørsel av soyabønner fordi soya er mye brukt i kraftfor og fiskefor, også i Norge. Dette er et problem fordi det landet i verden som dyrker mest soya i dag er Brasil, hvor utvidelse av soyaekspansjonen truer de tropiske regnskogene og andre artsrike naturtypene der.
Biobrensel
Biobrensel er en relativt ny pådriver for den økende etterspørselen etter korn, men som likevel er verdt å nevne. I 2011 høstet USA totalt 400 millioner tonn korn, hvor av 127 millioner tonn (32 %) omgjort til etanol (se Figur 2). Det er derfor klart at biobrensel er med å sette en ekstra belastning på kornproduksjon, samt konkurranse om land.
Settes dette inn i en ligning, kan det som nevnes over plasseres på høyre side under «etterspørsel», mens på andre side kan vi sette «produksjon». Ideelt sett skulle det vært en likevekt mellom disse sidene, men faktumet er at det på venstresiden er flere begrensende faktorer som konkurransen om landområdet, vann og energi. På toppen av det hele har vi den globale oppvarmingen som klusser til ting enda mer, og som gjør det nødvendig å minske de negative effektene matproduksjonen har på miljøet.
Vi står dermed ovenfor noe som er blitt kalt «en tredelt utfordring»:
- vi må møte den voksende etterspørselen som kommer fra en økende, og mer velstående befolkning,
- vi må gjøre dette på en bærekraftig måte,
- og vi må forsikre at de aller fattige ikke sulter.
Tidligere var svaret på økt etterspørsel å utvide områder som ble kultivert, men å utvide er vanskelig når land som tidligere kunne brukes til jordbruk mistes til urbanisering, ørkenspredning, jorderosjon og andre konsekvenser av jordbruk som er blitt drevet på ikke-bærekraftig vis. I tillegg er nødvendigheten for bevaring av biodiversitet og landområder en begrensende faktor for utvidelse.
Det er tydelig at mer mat nå må produseres på like store områder, helst mindre, noe som kalles «bærekraftig intensifiering». Det er nok nyvinninger innen teknologi som kommer til å bidra mest til dette, noe de fleste av oss ikke kan gjøre så mye med. Så hva kan vi gjøre?
Redusere avfall
I motsetning til i utviklingsland er det her lite som blir kastet av mat før maten når butikkene. Isteden er mengden mat som kastes i matforretningene, restauranter og i hjemmene våre latterlig (se Figur 3). Mye av årsaken ligger i vårt forhold til mat. De fleste av oss har for aldri opplevd fattigdom og matmangel. Mat har alltid vært så billig at vi ikke har lært oss nødvendigheten med å rasjonere og unngå avfall, det har streng tatt ikke vært nødvendig. Vi er så vant til at varene vi kjøper skal være i perfekt standard at det kastes med første avvik, både hjemme og i butikkene. Nye regelasjoner i matforretnings- og serviceleddet vil kunne redusere andelen av avfall betraktelig, men ingenting vil skje før vi som forbrukere forandrer forbrukerpresset. Vi kan se på matindustrien som et økosystem med et «top-down» design; hvor forbrukerne på toppen vil påvirke hva som skjer i de lavere nivåene.
Forandre hva vi spiser
Det sies at flere personer kan brødføs på mindre land dersom alle var vegetarianere siden kun er 10 % av energien i planter blir videreført til dyr. Dette fører til at ca. 1/3 av alle kornprodukter som produseres på verdensbasis går til dyrefor, noe som setter sterkt press på landområder og vannreservoarer. Likevel er ikke løsningen så «enkelt» som å si at all kjøttproduksjon er forferdelig og vi burde alle bli vegetarianere. I flere områder gresser ofte budskapet på områder som ikke har noen annen produktiv verdi for eksempel. Dette er tilfellet for norske sauer og geiter som tilbringer mye av sin tid i norske lyngheier. I tillegg er det stor forskjell i miljøbelastningen mellom type kjøtt. Her er storfe desidert verst; de kreves bl.a. 28 ganger så store landområder, 11 ganger mer vann og seks ganger så mye nitrogen enn annen type fe. I tillegg til å minke andelen kjøtt vi konsumerer bør vi derfor tenke over hvilken type kjøtt vi kjøper.
Det er absolutt ingen enkel løsning på matkrisen vi står ovenfor. Selv om jeg har min lit til fremtidige vitenskapelige og teknologiske innovasjoner ser jeg ikke dette som en grunn til å lene meg tilbake å la de som kan det ta seg av det. Vi som forbrukere har en unik mulighet til å være med å trekke matproduksjonen i mer bærekraftige baner, og den muligheten synes jeg vi har en plikt til å gripe.
Referanser
1. Brown, L.R. (2012). Full planet, empty plates: the new geopolitics of food scarcity. WW Norton & Company.
2. Eshel, G., Shepon, A., Makov, T. & Milo, R. (2014). Land, irrigation water, greenhouse gas, and reactive nitrogen burdens of meat, eggs, and dairy production in the United States. Proceedings of the National Academy of Sciences, 111, 11996-12001.
3. Germiso, M. & Eldholm, V. (2008). Soya spiser skogen. Om hvordan økt norsk soyaforbruk ødelegger natur i Brasil – og om botemidler Framtiden i våre hender Fredensborgveien 24 G, N-0177.
4. Godfray, H.C.J., Beddington, J.R., Crute, I.R., Haddad, L., Lawrence, D., Muir, J.F. et al. (2010). Food security: the challenge of feeding 9 billion people. science, 327, 812-818.
Klimaendringer i lys av artenes muligheter
Klimaendringer har eksistert siden tidenes morgen. Gjennom jordas historie har nedbør, vind og temperatur alltid variert i større eller mindre grad, og vi har opplevd både istider og varmere tidsperioder. Grunnene til dette kan ha vært endringer i jordens bane rundt solen, meteornedslag og vulkanutbrudd5. Klimaendringer er derfor noe vi ikke kan komme utenom. Det som likevel gjør klimaendringene så aktuelle i dag er at forskning peker i større eller mindre grad mot at det er oss mennesker som er skyld i vår tids temperatur- og nedbørsendringer. Siden starten på den industrielle revolusjonen på slutten av 1700-tallet og fram til i dag, så har konsentrasjonen av drivhusgasser økt betraktelig i atmosfæren som en følge av industrielle utslipp, bruk av fossilt brensel og avskoging av store landområder. Den økte konsentrasjonen av drivhusgasser i atmosfæren, som for eksempel CO2 og metan, er med på å forsterke drivhuseffekten, noe som betyr at jorda, i mindre grad enn før, reflekterer energistrålene som kommer fra sola, og som igjen gjør at temperaturen i atmosfæren øker. Konsekvensene av dette er at klimaet på jorden blir varmere. Man vil få mer ekstremvær og høyere havnivå, og dette vil igjen påvirke økosystemer og organismer i naturen. Viktige faktorer som matproduksjon til oss mennesker og biologisk mangfold1 kan også rammes. Naturen, og organismene rundt oss, vil en dag i nær eller fjern framtid måtte tilpasse seg klimaendringene for å overleve. Hvilke muligheter er det artene kan møte disse forandringene med? Hva slags verktøy kan de ta i bruk for å stå i mot klimaendringene? Dette ønsker jeg å drøfte videre i teksten.
Bilde hentet fra: http://guyanachronicle.com/know-about-climate-change/
Et mulig utfall er at artene kan tolerere klimaendringene4. Det vil rett og slett si at arten kan være i stand til å trives på tross av endringer i temperatur, vind og nedbør. Hver enkelt art kan oppleve værendringene forskjellig, og noen kan være så heldig at deres måte å overleve på ikke lar seg påvirke i stor nok grad til at de må søke andre alternativer for å overleve. De fleste arter har et spillerom som viser til endringer i klima som de kan tåle. For noen arter er dette spillerommet veldig lite, og for andre arter er det veldig stort. Det er de sistnevnte artene som er best rustet til å takle klimaendringene.
En annen mulighet er at artene kan tilpasse seg til endringene i klimaet6. Dette kan enten foregå ved at organismen tar i bruk innebygde egenskaper for å tilpasse seg miljøforandringene, eller det kan foregå ved at arten sine gener, etter en stund, forandrer seg slik at den innehar genetiske egenskaper som tåler klimaendringene på en bedre måte enn før. Dette kaller vi for adaptasjon. Av disse to så er det sistnevnte prosess som er den viktigste, da det kun er den som er i stand til å videreføre de bedre, og eventuelt nye, egenskapene til de kommende generasjonene. Dette er et eksempel på hvordan mikroevolusjon fungerer, og leder fram til det avgjørende spørsmålet om artene på jorda er i stand til å adaptere raskt nok til å stå i mot de stadige endringene i miljøet deres som følge av klimaendringene6. Om artene ikke skulle være i stand til å tilpasse seg, vil det i verste fall føre til utryddelser og tap av biologisk mangfold.
Bilde hentet fra: http://www.asrltd.com/images/marquee-expertise-ind/climate-change-adaptation-1.jpg
En annen utvei som er aktuell for mange arter vil være å forflytte seg4. For eksempel så vil arter som trives best ved en bestemt temperatur kunne forflytte seg oppover i landskapet til lavere temperaturer dersom det skulle bli for varmt i deres opprinnelige habitat. Og om havnivået skulle øke betraktelig, så vil dyr som lever nær sjøen bli tvunget til å finne seg levesteder som ikke er truet av vannstanden. Klimaendringer vil også kunne medføre at noen arter tilpasser seg bedre enn andre, slik at de vil utkonkurrere andre arter som lever i samme habitat. Dette vil igjen kunne føre til at noen arter må forflytte seg for å overleve.
Den siste, og mest uheldige, utveien er om arter ikke skulle klare å tilpasse seg klimaendringene. Om forandringene i miljøet blir for store til at man klarer å tilpasse seg, eller om andre arter rundt mestrer endringene mye bedre slik at man utkonkurreres, kan konsekvensene bli at arter ikke klarer å overleve og de kan utryddes2. IUCN, International Union for Conservation of Nature, har i dag listet opp 832 arter som utdødd, men kun hos 24 av dem har klimaendringene hatt en finger med i spillet3. Klimaendringer er derfor ikke en stor bidragsyter til at arter blir utryddet, men man bør ikke være i tvil om at stadige temperatur- og nedbørsendringer vil kunne skade habitater og levesteder, og før eller siden gjøre det vanskeligere for arter å overleve.
Kilder
- Fischlin et al. (2007). Ecosystems, their properties, goods, and services. Climate Change 2007: Impacts, Adaptation and Vulnerability. Cambridge University Press, Cambridge, 211-272.
- Garcia, R. A. et al. (2014). Multiple dimensions of climate change and their implications for biodiversity. Science, 344: 486-497.
- International Union for Conservation of Nature. (2014). The IUCN red list of threatened species. [Internett]. Tilgjengelig fra: http://www.iucnredlist.org/ (Nedlastet: 20. Februar 2015)
- Lenoir, J. og Svenning, JC. (2013). Latitudinal and Elevational Range Shifts under Contemporary Climate Change. Encyclopedia of Biodiversity, 3: 599-611.
- Petit, J. R et al. (1999). Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature, 399: 429-436.
- Visser, M. E. (2007). Keeping up with a warming world; assessing the rate of adaption to climate change. The Royal Society, 275: 649-659.
All Strangers are not foes
Conservation writer Emma Marris points that many ecologists and conservationists are prejudiced towards non-native species and preoccupied with the ‘native good and non-native bad’ dogma [1]. ‘non-native bad’ notion has much been influenced by philosophical standpoint regarding ‘nature’ and ‘natural’ and also by some overwhelmimg facts associated with some non-native species which have invaded new areas. An anlysis by Davis wilclove shows that Invasive Alien Species (IAS) is the second largest threat to bidiversity in the United states [2]. Much popular ‘IUCN Red List of Threaned species’ also points that IAS is a major cause of species threat and extinctions particularly of birds, fishes and mammals [3]. Many birds and mammals in oceanic islands have already been wiped out by feral species introduced intentionally or accidently. Brown tree snake on Guam-which eradicated 15 native birds, or the Nile Pearch-which caused extinction of 200 fish epitomises non-native species for many. Ecologists are worried that complex and heterogenous ecosystems are turning towards simple and monotonous with increased non-native species.
Of course, introduced species which turned themselves into invasive are real environmental and economic burden and they deserve management intervention, however, considering all non-natives as negetive appers too simple generalization. Management of invasive species is much influenced by native versus non-native dichotomy as pinted by Mark Davis [4].
‘non-native’ species have been vilified for driving beloved ‘native’ species to extinction and generally polluting ‘natural’ environments. Such characterizations have helped to create a pervasive bias against alien species that has been embraced by the public, conservationists….….. throughout the world.
It seems that ‘non-native species bad’ has been taken for granted by many policy makers and ecologists which creates bias towards non-natives. Here, I attempt to show that all non-natives are not bad rather they play role in conservation and restoration. And argue native non-native dichotomy largely overlooks social and ecolgical contribution of non-native species.
Ecologists have documented cases where introduced species have played substantial role to enhance biodiversity. Ascension island in the Atlantic-once considered as very poor by Darwin when he visited almsot 200 years ago- now is substantially richer in biodiversity compred to Darwin’s time. Now the area has been forested, species diversiy has manifolded-only one native tree has been accompained by 39 guest tree species [1]. Dov sax published a much counterintuitive result from a mata-anlysis ivolving all the oceanic islands aross the globe[5]. In the islands species brought by human have outnumbered the extinctin and the richness is higher than that would be in absence of introduction by humans. Ariel Lugo in Puerto Rico found that introduced tree plantation performed better in species diversity, biomass accumulaion and nutrient cycling than the native forests [6]. Similarly, a study comparing plant species richness between introduced and native pine forest in islands of western coast of norway reports higher richness in nn-native plantatins [7]. There are several instances where non-native species have supported and conserved native species by providing food and shelter, conserved rare species and substituted extant taxa [8].
But all biologists and ecologists can not enertain the ‘high biodiversity’ and restored ecosystems that contain non-native species. Instead of getting appreciation for their role in conserving other species and maintining diversity those species are getting an axe from environmental managers simply because they were originated somewhere else. Here ‘non-native bad/unnatural’ notion plays to rejection of diversity by nn-natives.
Contrary to ‘non-native bad’ generalization, there are several instances where non native species have played role in restoring the degraded ecosystems. US forest service scientist John Ewel opion that we can consider non-native species in restoration provided they do not pose serious threat to ecosystem health and provide social and ecological services [9]. Ariel Lugo based on his long term research at Puerto Rico concludes [6]:
The invasion of a site and the formation of an alien dominated forest serve important ecological functions, such as repairing soil structure and fertility, and restoring forest cover and biodiversity at degraded sites.
Pinus patula?, a native of mexican highlands brought to Nepal by Australian foresters has been successfully been used to restore degraded forest in hills of Nepal. This species made ground to regenerate native species. Now native broadleaved species are regenerating luxuriantly under the crown of non-native species.
Most of the extinction of native species particularly birds in ocenic islands is resulted from intertrophic interaction- by predation rather than competition. There are very rare instances of extincation in which introduced plant species is attributable culprit. Plant species do not predate but they may pose threat by altering habiat [10]. Therefore, categorically blaming non-native as cause of extincation is also biased.
Movement of species is pervasive and continous, we accept non-natives in fields, avenue plantations and cityscapes. It is likely that more species will move from one parts of world to other to meet aesthetic and economic needs. Eucalypts and mahogany for timber and cherries for urban beauty are accepted away from their origin. During remote past propagules of species might have transported far away from their historic ranges by storm, floods and birds. Species will move towards cooler places to respond global warming. Currently there are translocations of wildlife to save small population crashing. There are attempt even to introduce wildlife as proxy of extant species [1]. These continous flux of species questions the way non-natives are defined. Who knows, species capable of surviving in new environment may best fit in future climate and land use scenarios.
Spread of non-native species has became common phenomenon, definitely not an exception. Public, plicy makers and scientists should admit that environmenal threat has been posed by a small subset of non-native species. Judging species based on ‘what economic and ecological roles they play in new ecosystems’ may be more smart over judgement based on ‘where they originated’ [4, 11]. Native non-native dichotomy should be abandoned and and new classification of species based on their damage to ecosystem health and biodiversity may help manage non-native based on their ecological and economic roles.
References
- Marris E. 2011. Rambunctious GardenWilcove DS. 1997. Bioscience:
- Wilcove DS et al 1997. Bioscience 48(8):607-615
- IUCN 2004 IUCN Red List of Threatened Species.
- Davis MA et al.2011. Nature 474:153–154
- Sax DF. 2004. The American Naturalist. 160(6): 766-783
- Lugo AE 2004. Frnt Ecol Env. 2(5): 265–273
- Vetaas OR et al 2013. ?:1-13.
- Schlaepfer MA et al. 2011. Conservation Biology 25(3): 428-437
- Ewel JJ, Putz FE. 2004. Front Ecol Environ 2(7): 354–360
- Davis MA 2003. Bioscience 53(5): 481-489
- Warren CR 2007. Progress in Human Geography 31(4): 427–446
Lila Nath Sharma
The ivory gull, a high-Arctic specialist
by Vegard Finset Fjeldheim
The polar bear is by many regarded as the symbol of the Arctic. White and majestic, and very well adapted to its environment With Snowy Mountains and ice covered fjords. However, the polar bear is not the only animal that depends on the sea ice. The ivory gull is a high-Arctic seabird species, and the only bird associated with sea ice throughout the year [1, 2], It is pure white, with black legs and dark eyes, as shown in Figure 1 and 3 [3]. The ivory gull nest in colonies, sparsely distributed in the northern areas of Canada, Greenland, Norway (Svalbard) and western parts of Russia [1].It has a wide variety of food sources, primarily foraging on polar cod and crustaceans, but also human waste, carrions killed by polar bear and excrements and placenta etc. from marine animals [1]. Observations of the ivory gull, e. g. Inuit communities, indicated that the population was declining, and a study done by Canadian scientist showed a 80 % decline in numbers of nestling gulls in Arctic Canada [4]. What might be the reason for this declination, and do humans somehow contribute to it?
Figure 1. An ivory gull in a nestling colony at Spitsbergen, Svalbard.
It is believed that the ivory gull finds most of its pray close the the ice edge. By attaching small satellite transmitters to ivory gulls from Canadian islands, scientists has been able to monitor their movement during the year [5]. The monitored gulls rarely traveled over open waters free of ice, but tended to remain close to pack ice- and ice floe edges throughout the winter. The areas around Davis Strait and the Labrador Sea was found to important wintering areas for the ivory gull, most likely because these areas provide a predictable food supply along the pack ice edge. These areas are also found to be an important wintering destination for the nestling gulls in Svalbard and Russia [6]. The study also found that the individuals vary greatly in migration routs and timing, most likely due to the gulls affinity to the sea ice and their apparent avoidance of open water. The sea ice formation and extent in the fall vary from year to year, and the ivory gull will choose the migration route with the best foraging opportunities. With warmer temperatures, both in the ocean and atmosphere, the extent and timing of sea ice formation is changing and highly affecting the ivory gulls foraging opportunities, see Figure 2. Warmer ocean temperatures do not only have an impact on the sea ice, but might also alter the distribution of the gulls pray in the water masses [5].
(a) (b)
Figure 2. (a) show trends in the mean annual surface temperature from 1960-2011. The highest increase in temperature is found in the Arctic [11]. (b) show average monthly Arctic sea ice extent, with a blue trend line, in September, when the sea ice has its minimum extent [12].
The Arctic is not a clean area unaffected by human activity, but contaminants from the industrialized world is transported to the Arctic by various routes such as oceanic and atmospheric transport [7]. Here, the contaminants are easily incorporated in the Arctic ecosystems. Arctic animals can store large amount of fat for insulation and energy supply when food becomes sparsely [8]. Persistent organic pollutants (POPs) are one type of contaminants transported to the Arctic, and stored in the organism body fat when taken up in the biological system. Since the organisms have no efficient detoxification of such pollutants, it is stored and passed on to the next generation or next organism in the food chain if it is eaten. [2, 9], This means that animals situated high in the food chain may accumulate high levels of these contaminants. The ivory gull, that have polar cod and seal residues in its menu, have a high position in the Arctic food chain. To figure out the level of contaminants in ivory gulls, eggs collected from the Russian and Norwegian Arctic were analyzed [2]. They found that fat soluble organoclochlorines, including PCBs and DDE (a product from decomposition of DDT), dominated the contaminant profile, and the level was among the highest ever reported in Arctic seabirds. As noted in the article, the levels are lower than in eggs from birds of pray and gulls in the 1960s and 1970s in temperate areas when the use of these substances were not regulated, but local sources of emission in the Arctic are still relatively few. The effects of these pollutions are not very well known for the ivory gulls, but it is believed to have a negative long-term effect in the reproductive success. This is mainly based on other studies of seabirds at the top of the Arctic food chain that have shown reproductive, developmental, behavioral and immunological effects with even lover levels of contaminants than found in the ivory gull.
At The International Union for Conservation of Nature and Nature Resources’ (IUCN) Red List of Threatened species, the ivory gull is classified as near threatened with global warming and pollution as major threats [10]. And sadly, the gull is not itself responsible for these changes. It is believed that human activity has a large impact in the global warming we now are facing, and humans are for sure responsible for the pollutant found in ivory gulls and other species in the high-Arctic. On top of this, it is also believed that hunting of ivory gulls, mainly along the cost of Greenland, is a contributing factor to the declination, but the scope of this is not well known [1].
Figure 3. Will this be an even more rare sight in the future?
While we humans sit here in the «south» and live our normal lives, the price of this is paid among others by the ivory gulls and other high-Arctic animals. Our use of chemicals and increased emissions of climate gasses are effecting an changing the Arctic ecosystems and hence the habitat preferences of the ivory gull. How the ivory gull will deal with the declines of extent and duration of sea ice, and the consequences of this, is still not known, but the ivory gull is an ideal bioindicator of the effects of the global warming due to its proximity to the sea ice. To conclude, the ivory gull might be an Arctic climate refugee forced to flee by human activities.
References:
[1] Hallvard Strøm. Ismåken-en arktisk klimaflyktning? Vår Fuglefauna, 30:108–114, 2007.
[2] C. Miljeteig, H. Strøm, M. V. Gavrilo, A. Volkov, B. M. Jenssen, and G. W. Gabrielsen. High levels of contaminants in ivory gull Pagophila eburnea eggs from the russian and norwegian arctic. Enviromental Science & Technology, 40(14):5521–5529, 2009.
[3] Hallvard Strøm. Svalbards fugler. In K. M. Kovacs and C. Lydersen, editors, Svalbards fugler og pattedyr, pages 151–154.Norsk Polarinstitutt, polarhåndbok, 13 edition, 2006.
[4] H. G. Gilchrist and M. L.Mallory. Declines in abundance and distribution of the ivory gull (Pagophila eburnea) in arctic canada. Biological Conservation, 121:303–309, 2005.
[5] N. C. Spencer, H. G. Gilchrist, and M. L.Mallory. Annual movement patterns of endangered ivory gulls: The importance of sea ice. PLoS ONE, 9(12), 2014. doi:10.1371/journal.pone.0115231.
[6] O. Gilg, H. Strøm, A. Aebischer, M. V. Gavrilo, A. E. Volkov, C. Miljeteig, and B. Sabard. Post-breeding movements of northeast atlantic ivory gull Pagophila eburnea populations. Journal of Avian Biology, 41:532–542, 2010. doi:19.1111/j.1600-048x.2010.05125.x.
[7] I. C. Burkow and R. Kallenborn. Sources and transport of persistent pollutants to the arctic. Toxicol. Lett., 112:87–92, 2000.
[8] Pål Prestrud. Adaptions by the arctic fox (Alopex lagopus) to the polar winter. Arctic, 44(2):132–138, 1991.
[9] Samuel C. Byrne. Persistent organic pollutians in the Arctic. A Report for the Delegates of the 4th Conference of the Parties Stockholm Convention on Persistent Organic Pollutants, 2009
[10] The IUCN Red List of Threatened Species. Pagophila eburnea. Version 3, 2014. <www.iucnredlist.org>. Downloaded on 19 February 2015.
[11] National Snow & Ice Data Center. Climate Change in the Arctic <https://nsidc.org/cryosphere/arctic-meteorology/climate_change.html> Downloaded on 19 February 2015.
[12] National Snow & Ice Data Center. Poles apart: A record-breaking summer and winter <http://nsidc.org/arcticseaicenews/2012/10/poles-apart-a-record-breaking-summer-and-winter/> Downloaded 19 February 2015.