Global Warming – BIOL3056 2016/17

The Grass isn’t always Greener on the other side

Posted on March 23, 2017 by Cameron Little

*Photo credit https://loristillman.files.wordpress.com/2013/04/screen-shot-2013-04-30-at-6-07-14-am.png?w=764*

Despite what certain orange men in white buildings may say. It is an inconvenient truth that Global Climate Change is occurring (Kerr, 2001) and may in fact not be a lie created by the Chinese.

What is more up for debate however, is exactly what is going to happen to the earth over the next hundred years. Among many problems better left unsaid, a concept has emerged that global climate change may lead to increased growth rates amongst plants (Nemani, 2003).

As a result of the inputs of additional carbon dioxide into the atmosphere from man-made sources, photosynthesis rates have increased; which has ultimately led to increased plant growth. On the surface of things this may sound like a good result, however below the surface i.e under the sea; this can have entirely different implications.

The increase of carbon dioxide levels in the atmosphere has also led to an increasing global temperature as well as an increasing ocean temperature (Hansen et al,. 2006). Many underwater plants may be detrimentally affected by this including the vast meadows of seagrass which support many of our favourite undersea critters such as the manatee.

*A manatee swimming, blissfully unaware of all life’s problems that may await him. Photo credit: https://www.fws.gov/caribbean/images/Moises_by_Alejandro_Avampini.jpg*

Most organisms on this planet can only live within a certain range of temperatures and when plants or animals are pushed beyond this range they can struggle to survive.

(No prizes for guessing what this means?)

Warming associated with climate change is causing many animals and plants to move beyond their comfortable ranges (Walther et al,. 2002). This is true for many species of temperate seagrasses which are struggling with rising temperatures (Short and neckless, 1999). Increasing temperatures are pushing them out of their desired temperature range of between the lower end of 21 and 32 °C; causing them to a enter a thermal stress. This facilitates a breakdown of a crucial step in photosynthesis known as ‘photosystem II’ (Koch et al,. 2012) and prevents them from photosynthesizing properly.

To make matters worse, other more tropical species of seagrass may begin to move in to temperate seagrasses habitats, as the warmer temperatures allow them to occupy and outcompete them for space. This is because as opposed to temperate species, warmer temperatures of around 27 – 33 °C tend to increase the photosynthetic rates of tropical species (Koch et al,. 2012).

*A beautiful seagrass meadow, blissfully unaware of all life’s problems that await it. Photo credit: http://www.stevedeneef.com/index/G00000uAGDq2A_UQ/thumbs*

But like all things in life the tropical seagrass species can’t have it all. As in their native tropical environments some species are far more susceptible to temperature changes and subsequent increases will cause a breakdown of photosystem II, which leads to heat-induced photoinhibition (Campbell, McKenzie and Kerville, 2006). This subsequently means its ability to photosynthesize is reduced.

In closing it appears that many of the undersea grasses found globally, that are so crucial to many species on earth are going to be negatively affected by global climate change. And if nothing is done to stop it, we could be saying goodbye to a truly beautiful part of nature.

Word count – 489

References

Campbell, S., McKenzie, L. and Kerville, S. (2006). Photosynthetic responses of seven tropical seagrasses to elevated seawater temperature. Journal of Experimental Marine Biology and Ecology, 330(2), pp.455-468.

Hansen, J., Sato, M., Ruedy, R., Lo, K., Lea, D. and Medina-Elizade, M. (2006). Global temperature change. Proceedings of the National Academy of Sciences, 103(39), pp.14288-14293.

Kerr, R. (2001). GLOBAL WARMING: Rising Global Temperature, Rising Uncertainty. Science, 292(5515), pp.192-194.

Koch, M., Bowes, G., Ross, C. and Zhang, X. (2012). Climate change and ocean acidification effects on seagrasses and marine macroalgae. Global Change Biology, 19(1), pp.103-132.

Nemani, R. (2003). Climate-Driven Increases in Global Terrestrial Net Primary Production from 1982 to 1999. Science, 300(5625), pp.1560-1563.

Short, F. and Neckles, H. (1999). The effects of global climate change on seagrasses. Aquatic Botany, 63(3-4), pp.169-196.

Walther, G., Post, E., Convey, P., Menzel, A., Parmesan, C., Beebee, T., Fromentin, J., Hoegh-Guldberg, O. and Bairlein, F. (2002). Ecological responses to recent climate change. Nature, 416(6879), pp.389-395.

Photo credits

Loristillman, (2017). The Grass is Green Where You Water It. [online] Loristillman.files.wordpress.com. Available at: https://loristillman.files.wordpress.com/2013/04/screen-shot-2013-04-30-at-6-07-14-am.png?w=764 [Accessed 19 Mar. 2017].

Steve De neef, (2017). Steve De Neef Photography. [online] Stevedeneef.com. Available at: http://www.stevedeneef.com/index/G00000uAGDq2A_UQ/thumbs [Accessed 20 Mar. 2017].

US Fish and Wildlife Service, (2017). Antillean Manatee Fact Sheet. [online] Fws.gov. Available at: https://www.fws.gov/caribbean/images/Moises_by_Alejandro_Avampini.jpg [Accessed 20 Mar. 2017].

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UK Food in a climate crisis?

Posted on March 23, 2017 by Phoebe O'Brien

British food security is under threat due to Climate change.

If you haven’t heard of ‘climate change’ you‘ve either been living under a rock for the last 30 years or getting yourself elected as leader the free world. But not much has changed, Winter’s a little warmer, summer’s a little wetter? We’ve heard of extreme weather conditions in some far corners of the globe but unless you’ve been planning a trip there, it’s unlikely to affect our everyday lives. But behind supermarkets sliding doors lurks a real peril, one directly impacting Britons at their most vulnerable part, our Achilles heel, our pockets. As crop production is jeopardised, already inflated prices are set to rise, correlating with the environmental changes induced by human pollution (Lobell, 2007).

Figure 1. A familiar slight, well stocked fruit and veg for public consumption. But for how long? (WordShore (flickr), 2016)

Food security is perhaps the most important commodity provided by the planet. At a glance the effects of climate change, seem on the whole, to be exactly what farmers are looking for in terms of improving yield from their crops. It’s wet, hot, there’s more CO2, more decomposition and available nutrients, just what plants need right? But this is not always the case, although higher CO2 levels does stimulate plant growth, it is counteracted by the increase in temperature and ozone, a molecule with harmful effects on plant tissue(Hogsett, et al 1997). Warming decreases the quality of the crops produced, grains are less dense and seeds contain less oil, as well as favouring growth and proliferation of weeds into new areas, due to the differences in how they photosynthesise (Fuhrer, 2003. Martre, 2017).

Figure 2. The graph from DEFRA (Department for Environmental Food and Rural Affairs) shows billions of pounds worth of imported food, especially fruit and vegetables. (Source: DEFRA Food Statistics Pocketbook 2016) — Figure 2. This graph from DEFRA (Department for Environmental Food and Rural Affairs) shows billions of pounds worth of imported food, especially fruit and vegetables. (Source: DEFRA Food Statistics Pocketbook 2016)

It is no secret that as a nation we currently import almost half of our food and animal feed from overseas (Ruiter et al 2015). In response to huge population increases of 3 Million on average every decade since the baby boomers of the 50s(Humby, 2016) and market for year-round exotic produce. But tropical regions are likely to suffer much more, even a slight temperature increase interfering with developmental and growth processes beyond already stretched thresholds, meaning production in these areas will fall hugely(Challinor, 2008). Excess precipitation, effectively drowning roots and drought adding another uncertain dimension to the mix(Amedie, 2013).

“[In staples like wheat, maize and barley] warming has resulted in annual combined losses of $5 billion per year, as of 2002” -Lobell, 2007

Environmental change is going to effect everyone in one way or another, we rely on plants for food, clothing, oxygen, medicine and much more. Prices of everyday commodities reflect the quantity and quality of production processes. The result is innumerable aspects of our lives being changed, in some way by the unsustainable practices we are complicit to on a daily basis(Lepetz et al., 2009).

Research into genetic modification of crop plants provides some relief in the challenges ahead, improving crop plant coping mechanisms and yield potential (Martre et al 2017), as well as a decrease in the consumption of animal products due to their high carbon footprint and inefficiency(Ruiter et al 2015). For now it will be a 4p increase in a farmhouse loaf and 10p extra for sunflower oil, but immediate action is necessary to prevent a large-scale food shortage in the near future.

[500 words]

References:

Amedie, F.A., (2013). Impacts of Climate Change on Plant Growth, Ecosystem Services, Biodiversity, and Potential Adaptation Measure. , pp.1–61.

Challinor, A.J. & Wheeler, T.R., (2008). Crop yield reduction in the tropics under climate change: Processes and uncertainties. Agricultural and Forest Meteorology, 148(3), pp.343–356.

Fuhrer, J., (2003). Agroecosystem responses to combinations of elevated CO2, ozone, and global climate change. Agriculture, Ecosystems and Environment, 97(1–3), pp.1–20.

Hogsett, W.E., J.E. Weber, D. Tingey, A. Herstrom, E.H. Lee and J.A. Laurence. (1997). An approach for characterizing tropospheric ozone risk to forests. Environmental Management 21:105-120.

Humby, P. (2016). Overview of the UK population: February 2016. [ONLINE] Available at: https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationestimates/articles/overviewoftheukpopulation/february2016. [Accessed 13 March 2017].

Lepetz V., Massot, M. & Schmeller, D.S., & Clobert, J., (2009). Biodiversity monitoring: some proposals to adequately study species’ responses to climate change. Biodiversity and Conservation 18, 3185- 3203

Lobell, D.B. & Field, C.B., (2007). Global scale climate–crop yield relationships and the impacts of recent warming. Environmental Research Letters, 2(1), p.14002.

Martre, P., Yin, X. & Ewert, F., (2017). Modeling crops from genotype to phenotype in a changing climate. Field Crops Research, 202, pp.1–4. Available at: http://linkinghub.elsevier.com/retrieve/pii/S0378429017300242.

Ruiter, H. de et al., (2015). Global cropland and greenhouse gas impacts of UK food supply are increasingly located overseas. Journal of The Royal Society Interface, 13(114). Available at: http://rsif.royalsocietypublishing.org/content/13/114/20151001.abstract.

WordShore (flickr), (2016), Fruit (WordShore)[ONLINE]. Available at: https://hiveminer.com/Tags/hebrides,solas [Accessed 15 March 2017].

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It’s getting hot in here! Can plants handle global warming?

Posted on March 23, 2017 by Catherine Savage

Looking at the potential future impacts of climate change on global plant life By Catherine Savage, University of Southampton student

The human race is turning over a new leaf – but not in a good way.

As we enter a new era, the Anthropocene, what will be the fate for plant life on earth?

Everyone knows what climate change is, everyone knows that it is a current hot topic, but does everyone know what is happening to our plants because of it?

Global temperatures have risen 0.9 degrees throughout the last century (IPCC, 2013). This is predicted to rise by 4 degrees before 2100 (Thuiller, 2007). A shocking reality to grasp, yet global temperature change is only one aspect encompassed in the concept of climate change. What about changes in rainfall? Ice sheet melting? Sea level rise?

So, what are the underlying causes of climate change? Out of the greenhouse gases, carbon dioxide contributes the most to global warming at 65%. Current carbon dioxide concentration in the atmosphere is 387ppm, exceeding the safe level of 350ppm (Hansen et al., 2015). This has been heightened by fossil fuel burning and land-use change. The extra CO₂ increases the greenhouse effect, resulting in trapped heat in the atmosphere which causes warming of the planet (Oktyabrskiy, 2016). For plants, this could either be a blessing or a curse.

Plate 2. The world map showing projected daily temperatures in July by 2100, under predicted carbon dioxide levels of 935ppm (Gray, 2015). — **Plate 1.** The world map showing projected daily temperatures in July by 2100, under predicted carbon dioxide levels of 935ppm (Gray, 2015).

The good…

Climate change may be beneficial for plants:

Enhanced CO₂ can increase the photosynthetic rate of plants, which could balance the effect of temperature increases (Thuiller, 2007).
With warmer soils, the decomposition rate of organic matter will increase, allowing plants a higher mineral and nutrient availability.
Growing seasons for crops may be extended and we could witness an improved agricultural productivity (Brown et al., 2016).

The bad…

However, it would be reckless to keep adding CO₂ to the atmosphere. Too much of a good thing can be a bad thing right? Once you increase one substance, plants need to increase the rest too! Plants will be incapable of meeting these new requirements.

Changes in rainfall patterns and temperatures can further exacerbate abiotic stresses such as (Naithani, 2016):

Drought
Waterlogged soils
Saltwater inversion
Metal contamination

These impacts and more make it hard for plants to thrive, with the overarching impact of stunted growth (Worland, 2015).

Plate 2. The invasive Bromus tectorum, a species of the genum Bromus. It is known as the drooping brome or cheat grass. — **Plate 2**. The invasive Bromus tectorum, a species of the genum *Bromus*. It is known as the drooping brome or cheat grass. (Source: www.biology.csusb.edu)

Plus, non-native plant species may cross frontiers as conditions become more suitable, out-competing native plants (Thuiller, 2007; Smith et al., 2016; Walter et al., 2002).

The species of long grass, Bromus tectorum, has risen above native plant species in western North America due to being more suited to changes in the wet seasons (Smith et al., 2000).

The ugly…

The human race is a selfish species, perhaps the only way to kick people into action is to present the fact that no plants means no food. Crops won’t grow, land will become barren and food insecurity will explode (Worland, 2015). Could climate change wipe out homo sapiens as well as the worlds plants?

On a lighter note, the outlook may seem dire, but it is not too late for change. As the UN Secretary General Ban Ki-Moon quite rightly stated we are “the last generation that can end climate change”. We can protect and preserve our plants that will provide security to our future generations. Let’s all stop waiting for someone else to solve our problems, and be the change ourselves.

Word count: 499

References:

IPCC (2013) Climate change: the physical science basis. Working group contribution to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, UK and New York, USA.
Thuiller, W. (2007) Biodiversity: climate change and the ecologist.Nature,448(7153), pp.550-552.
Hansen, J., Sato, M., Ruedy, R., Lo, K., Lea, D.W. and Medina-Elizade, M. (2015) Global temperature change. Proceedings of the National Academy of Sciences, 103(39), pp.14288-14293.
Oktyabrskiy, V.P. (2016) A new opinion of the greenhouse effect.St. Petersburg Polytechnical University Journal: Physics and Mathematics,2(2), pp.124-126.
Brown, I., Thompson, D., Bardgett, R., Berry, P., Crute, I., Morison, J., Morecroft, M., Pinnegar, J., Reeder, T., and Topp, K. (2016) UK Climate Change Risk Assessment Evidence Report: Chapter 3, Natural Environment and Natural Assets. Report prepared for the Adaptation Sub-Committee of the Committee on Climate Change, London.
Gray, R. (2015) Our scorched Earth in 2100: Nasa maps reveal how climate change will cause temperatures to soar. [online] Available at: http://www.dailymail.co.uk/sciencetech/article-3125113/Earth-2100-Nasa-maps-reveal-world-need-adapt-rising-temperatures-caused-climate-change.html [Accessed 20 March 2017].
Naithani, S. (2016) Plants and global climate change: A need for sustainable agriculture. Current Plant Biology,6(2), p.1.
Worland, J. (2015) The weird effect climate change will have on plant growth. [Blog]Time. Available at: http://time.com/3916200/climate-change-plant-growth/ [Accessed 6 Mar. 2017].
Smith, S.D., Huxman, T.E., Zitzer, S.F., Charlet, T.N., Housman, D.C., Coleman, J.S., Fenstermaker, L.K., Seemann, J.R. and Nowak, R.S., (2000) Elevated CO₂ increases productivity and invasive species success in an arid ecosystem.Nature,408(6808), pp.79-82.
Walther, G.R., Post, E., Convey, P., Menzel, A., Parmesan, C., Beebee, T.J., Fromentin, J.M., Hoegh-Guldberg, O. and Bairlein, F., (2002) Ecological responses to recent climate change.Nature,416(6879), pp.389-395.

Read more:

http://journal.frontiersin.org/article/10.3389/fpls.2016.01123/full

http://www.open.edu/openlearncreate/mod/oucontent/view.php?id=22627&printable=1

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Invasion of the Arctic: How warming temperatures have led to non-native species introduction

Posted on March 23, 2017 by Anonymous

Source: Animal Club (2017) Available from: http://elelur.com/mammals/arctic-fox.html — Arctic Fox (Animal Club, 2017. Available from: http://elelur.com/mammals/arctic-fox.html)

In the eyes of an arctic fox (Alopex lagopus), the temperatures of the tundra provide seamless living conditions. Their adaptations to low temperatures make their arctic habitats suitable for them to hunt, reproduce and in turn survive. However, their survival is threatened by increasing temperatures in the arctic, as it has become more suitable for red foxes (Vulpes Vulpes), too (Killengreen et al., 2007). As the red fox invades the territory of the arctic fox, they undergo competition for land and prey. Although this has not led to a direct decline in arctic fox numbers, it can have further impacts on food webs and community dynamics within the Arctic ecosystem (Gallant et al., 2012).

This is just an example of the new reality in the Arctic; ice is melting due to increased temperatures, and the ecosystem is changing vastly (Serreze et al., 2000). Many of us are aware that global temperatures are rising due to increased greenhouse gas emissions entering the atmosphere, however the rate of temperature change varies across the globe. Where average temperatures have increased by 0.4°C over the past 150 years, it is believed that warming in arctic regions has been almost 3 times higher (IPCC, 2014).

The increased warming creates an environment which is suitable for other, non-native species (Post et al., 2009) – such as the example of the Red Fox. Species towards the South of the Arctic have increased their range, placing pressure on the existing Arctic communities (Root et al., 2003). This ‘invasion’ is not limited to animal species; invasive species in the form of plant communities can also intrude on the ecosystem. For example, the warming has allowed shrub tundra to expand into a wider variety of habitats, and Boreal forest has begun to infringe on the tundra ecosystem (Hinzman et al., 2005).

Source: Animal Photgraphics (2017) Available from: http://alaskaphotographics.photoshelter.com/image/I00009qTaSPpYpaA — Arctic Ground Squirrel. (Animal Photgraphics, 2017. Available from: http://alaskaphotographics.photoshelter.com/image/I00009qTaSPpYpaA)

Another example is of the arctic ground squirrel (Urocitellus parryii), which acts as an ecosystem engineer through its key role in the food web (Wheeler, 2011). The arctic ground squirrel burrows into vegetated land as a mechanism for survival. The burrowing action also changes the composition of the soil, which is important for other ecological processes. However, as boreal, woody forests become more prominent than the easily accessible vegetation, the arctic ground squirrel loses its habitat (Donker & Krebs, 2011).

Figure 1. Predicted global surface temperature change, based on carbon emissions scenarios (IPCC, 2013).

The Arctic ecosystem is so complex that the full effects of climate change are not yet understood. This means that the invasive species described above have the potential to interrupt even more ecological processes and food webs. This could also affect human livelihood as we also rely on the stability of the food chain for survival. Furthermore, global warming is expected to cause temperatures to increase even more, dependent on emissions scenarios (Figure 1). This would cause the number of invasive species in both terrestrial and marine ecosystems to increase, threatening the existing communities to an even greater extent.

References

Donker, S. A., Krebs, C. J. (2011) Habitat Specific Distribution and Abundance of Arctic Ground Squirrels (Urocitellus parryii) in Southwest Yukon. Canadian Journal of Zoology, 89, 570-576.

Gallant, D., Slough, B. G., Reid, D. G., Berteaux, D. (2012) Arctic fox versus red fox in the warming Arctic: four decades of den surveys in north Yukon. Polar Biology, 35(9), 1421-1431.

Hinzman, L. D., Bettez, N. D., Bolton, W. R. et al. (2005) Evidence and Implications of Recent Climate Change in Northern Alaska and Other Arctic Regions. Climatic Change, 72(3), 251-298.

IPCC (2013) Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp.

IPCC (2014) Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. IPCC, Geneva, Switzerland, 151 pp.

Killengreen, S. T., Ims, R. A., Yoccoz, N. G., Brathen, K. A., Henden, J., Schott, T. (2007) Structural Characteristics of a Low Arctic Tundra Ecosystem and the Retreat of the Arctic Fox. Biological Conservation, 135(4), 459-472.

Post, E., Forchhammer, M. C., Bret-Harte, S. M. et al. (2009) Ecological Dynamics Across the Arctic Associated with Recent Climate Change. Science, 325(5946), 1355-1358.

Root, T. L., Price, J. T., Hall, K. R., Schneider, S. H., Rosenzweig, C., Pounds, J. A. (2003) Fingerprints of Global Warming on Wild Animals and Plants. Nature, 421, 57-60.

Serreze, M. C., Walsh, J. E., Chapin, F. S., III, Osterkamp, T., Dyurgerov, M., Romanovsky, V., Oechel. W. C., Morison, J., Zhang, T., Barry, R. G. (2000) Observational Evidence of Recent Change in the Northern High Latitude Environment. Climate Change, 46, 159-207.

Wheeler, H. C. (2011) Arctic Ground Squirrels Urocitellus parryii as Drivers and Indicators of Change in Northern Ecosystems. Mammal Review, 43, 238-255.

[479 Words]

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Crops and Climate Change: the good, the bad and the ugly truth

Posted on March 23, 2017 by Anonymous

New Year, New Hope? But 2017 began with Britain being hit with a vegetable shortage!

(Independent, 2017) (The Guardian, 2017)

But apart from halting our “clean eating” resolutions…..

Is a courgette shortage really the end of the world?

Well, probably not! But globally, food security is no laughing matter.

And what is the cause you may ask? Climate change, of course!

The evidence for climate change is overwhelming.

The Earth’s average temperature has increased by 0.85°C between 1980-2012 (IPCC, 2014). This may seem insignificant, yet, it has severe consequences, such as the ice caps melting, sea levels rising and increased occurrence of extreme weather events (Overpeck and Cole, 2006).

Globally averaged combined land and ocean surface temperature (IPCC, 2014)

Humans are to blame.

Since the industrial revolution, burning of fossil fuels has increased emissions of carbon dioxide (CO₂) and other greenhouse gases (GHGs) These GHGs act as a blanket, trapping energy in the atmosphere, causing Earth’s temperature to rise (IPCC, 2014).

Global Human CO₂Emissions, IPCC, 2014

The good?

Higher CO₂levels increase plant photosynthesis (Pospisilova and Catsky, 1999). Photosynthesis depends on an enzyme called Rubisco, which evolved at higher prehistoric CO₂ levels, therefore has higher activity when CO₂ increases (Bowes, 1996). This increases plant growth, thereby increasing crop yield, in a phenomenon termed “CO₂-fertlisation” (Allen, 1990).

This is particularly pronounced plants categorised at C3 , which includes major crops such as rice, wheat and soybean. Increasing CO₂ to 550pm causes 10-20% increase in C3 crop yield, but only 0-10% increase plants categorised as C4, which includes the crops maize and sorghum (Schmidhuber and Tubiello, 2007).

CO₂ enters plants through stomata (plant pores), therefore, at higher CO₂ levels the stomata need not open as often, termed reduced stomatal conductance. This decreases the amount of water lost through the pores in the process of transpiration, thereby increasing the water efficiency of the plants (Drake et al., 2007).

The bad?

So, is climate change good for plants if it causes increased growth and higher water efficiency? Well no, it was never going to be that simple…

Extreme weather events negatively impact food security, both directly by reduced yields from damaged crops but also indirectly by increasing the chance of landslides and soil erosion, thereby reducing the land available for agriculture (Cerri et al., 2007).

This issue is becoming more urgent as global population increases at an unprecedented rate, increasing the demand for food (MA, 2005).

Food security issues are not only concerned with the quantity of food but also the quality, as globally many people suffer from malnutrition (MA, 2005). Elevated CO₂ decreases the zinc, iron, and protein content in wheat, barley, and rice (Myers et al., 2014).

The two-fold effect of increased CO₂form increased carbon emissions; most likely the negative effect will outweigh the positive effect.

The ugly truth

Unfortunately, it is predicted the losses will outweigh any gains from CO₂ fertilisation.

Ultimately, lack of food could see increased prices for consumers in the developed world whilst the developing world will suffer with food shortage and malnutrition.

Lack of courgettes may seem a trivial matter but is it just one more sign that we getting closer to the tipping point of our planet’s ability to cope with climate change.

Word count: 499

References

Allen, L.H. Jr. (1990). Plant responses to rising carbon dioxide and potential interactions with air pollutants. J. Environ. Qual, 19: 15-34.

Bowes G. (1996) Photosynthetic responses to changing atmospheric carbon dioxide. pp. 387-407. In: N.R. Baker (ed.). Photosynthesis and the Environment. Advances in Photosynthesis, Vol. 5, Kluwer, Dordrecht

Cerri, C. E.P., Sparovek, G., Bernoux, M., Easterling, W.E., Melillo, J. M., and Cerri C. C. (2007). Tropical Agriculture and Global Warming: Impacts and Mitigation Options. Sci. Agric., 64(1): 83-89.

Drake, B.G., Gonzàlez-Meler, M.A. and Long, S.P., 1997. More efficient plants: a consequence of rising atmospheric CO2? Annual review of plant biology, 48(1): 609-639.

IPCC. (2014) Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. R.K. Pachauri and L.A. Meyer (eds.). IPCC, Geneva, Switzerland, pp. 151.

Millennium Ecosystem Assessment (2005). Ecosystems and Human Well-being: Synthesis. Island Press, Washington, DC.

Myers SS, Zanobetti A, Kloog I, et al. (2014). Rising CO2 threatens human nutrition. Nature. 510(7503): 139-142.

Overpeck, J.T. and Cole, J.E. (2006). Abrupt change in Earth’s climate system. Annual Review of Environment and Resources, 31: 1-31.

Pospisilova, J. and Catsky, J. (1999). Development of water stress under increased atmospheric CO2 concentration. Biologia Plantarum, 42: 1-24.

Schmidhuber, J. and Tubiello, F.N. (2007). Global food security under climate change. Proc. Natl. Acad. Sci. USA, 104(50): 19703-8.

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Is Forest Fragmentation The “New” Deforestation?

Posted on March 22, 2017 by Ariadne Wilkinson

Global Forest Fragmentation is destroying our most important ecosystems.

It’s a well-known fact that deforestation is happening at extreme rates! Just look at the Amazon rainforest, where 20 football pitches worth of trees are removed every minute (Carrington, 2013). These global environmental changes are associated with our topic for today: fragmentation!

WHAT IS FRAGMENTATION?

Forest fragmentation occurs when the total cover of a native forest is reduced. It is associated with anthropogenic deforestation, and leads to patchy forests and overall forest loss (Murcia, 1995) (Kupfer et al, 2006).

The isolated patches of forested habitats (remnants) in between the cleared forest cover follow the theory of ‘Island Biogeography’. Principles of Island Biogeography link forest fragmentation with biodiversity loss (Kupfer et al, 2006).

This is a good representation of forest fragmentation by Bacles & Jump (2011). The remnants have a drastically different ecosystem than their surroundings, just like an Island’s ecosystem is isolated from the outside world.

FRAGMENTATION EFFECTS ON ECOSYSTEMS

– Microclimate Change (Saunders et al, 1991)

The microclimate within and surrounding the remnant forest is altered in the following ways:

More solar radiation. This restricts shade-tolerant species and encourages the spread of new species of plants (ex. vines, secondary vegetation) and animals to occupy the forest clearings and edges.

The accompanied temperature rise alters soil moisture and nutrient availability, modifying the local vegetation. It also disturbs species interactions and animal foraging behaviours (ex. Carnaby’s cockatoos).

Image by Georgina Steytler: A Carnaby’s Black-Cockatoo (Calyptorbynchus funereus latirostrus). Higher temperatures in fragmented cockatoo habitats reduced their foraging time available, which led to their local extinction in areas of Western Australia (Saunders et al, 1991) — Image by Georgina Steytler: A Carnaby’s Black-Cockatoo (*Calyptorbynchus funereus latirostrus*). Higher temperatures in fragmented cockatoo habitats reduced their foraging time available, which led to their local extinction in areas of Western Australia (Saunders et al, 1991).

Stronger winds. Reducing the denseness of the forest leaves it more exposed to penetrating winds. That, amongst other things, changes vegetation structures and food availability for the forest communities.

Increased water flux. Fragmented forests alter the landscape through heavy water flows that erode the topsoil and transport more particulate matter across the forest cover.

– Isolation (Saunders et al, 1991)

Remnant forest habitats are usually left crowded, with more species than they can actually support. Therefore, over time species will inevitably be lost due to the lack of resources and space available.

Species survival will generally depend on how well they can adapt to new conditions or migrate to new areas. The most rapid extinctions will occur for species with small populations, or ones that are heavily dependent on native vegetation or large territories.

– Greenhouse Effect

Tropical rainforests store large amounts of carbon. Destroying them releases this stored carbon into the atmosphere and largely contributes to global warming (Laurance et al, 2002).

MADAGASCAR

Fragmentation is a serious issue for this biodiversity hotspot, and its all due to human activities.

Fragmentation is a major concern for Madagascar: The original extent of the eastern rainforest was around 3 times larger than what it currently is!

Prior to human colonisation the forest on the eastern highland spine of Madagascar was 11.2 million ha, but by 1985 it only covered 3.8 million ha (Green & Sussman, 1990). (These satellite images can be found in Conservation Corridor).

Its size is diminishing due to fires, illegal logging and agricultural deforestation (Ganzhorn et al, 2001).

The forest on the Eastern Highland spine of the island is shrinking very fast. Forest can only survive within the gullies, where the fires can’t reach it. Image by: Josia Razafindramanana.

Many larger species have been lost, and the remainder are unlikely to maintain viable populations beyond 2040. Populations of lemurs with fewer than 40 adults cannot survive. Worryingly, none of the remnant patches on the eastern Madagascar forest are large enough to maintain even such populations (Ganzhorn et al, 2001).

Lemurs are holding on to the trees for dear life. The high rate of fragmentation is a major concern for these primates, as well as for all of Madagascar’s endemic forest ecosystems. Image by Frank Vassen.

THE ONLY SAVING GRACE: CONNECTIVITY

Corridors to connect remnants have proven useful when striving to enhance biodiversity.

They can aid the re-colonisation and immigration of species, provide refuge, and help with further species interactions (Saunders et al, 1991) (Laurance et al, 2002).

The size and shape of the remnants can also affect its vulnerability to external factors:

The best conditions for the conservation management of the ecosystems within remnant patches or forest (here they are termed ‘reserves’ from the “Island-like reserves” biogeography theory) can be seen in this image. The theory of forest connectivity is linked to this.

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FOR MORE INFORMATION ON:

Fragmentation effects on ecosystems you can watch: https://www.youtube.com/watch?v=lzf-uX6kGkk

How Madagascar is managing its lemur populations you can watch: https://www.youtube.com/watch?v=ZhOyD79ymJA

REFERENCES:

Carrington, D. (2013). Amazon deforestation increased by one-third in past year. [online] the Guardian. Available at: https://www.theguardian.com/environment/2013/nov/15/amazon-deforestation-increased-one-third [Accessed 18 Mar. 2017].

Ganzhorn, J., Lowry, P., Schatz, G. and Sommer, S. (2001). The biodiversity of Madagascar: one of the world’s hottest hotspots on its way out. Oryx, 35(04), p.346.

Green, G. and Sussman, R. (1990). Deforestation History of the Eastern Rain Forests of Madagascar from Satellite Images. Science, 248(4952), pp.212-215.

Kupfer, J., Malanson, G. and Franklin, S. (2006). Not seeing the ocean for the islands: the mediating influence of matrix-based processes on forest fragmentation effects. Global Ecology and Biogeography, 15(1), pp.8-20.

Laurance, W., Lovejoy, T., Vasconcelos, H., Bruna, E., Didham, R., Stouffer, P., Gascon, C., Bierregaard, R., Laurance, S. and Sampaio, E. (2002). Ecosystem Decay of Amazonian Forest Fragments: a 22-Year Investigation. Conservation Biology, 16(3), pp.605-618.

Murcia, C. (1995). Edge effects in fragmented forests: implications for conservation. Trends in Ecology & Evolution, 10(2), pp.58-62.

SAUNDERS, D., HOBBS, R. and MARGULES, C. (1991). Biological Consequences of Ecosystem Fragmentation: A Review. Conservation Biology, 5(1), pp.18-32.

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Gassy Greens and Growing Veg: the hotter future of the Arctic

Posted on March 13, 2017 by Clara Kan

**Polar Bears rowing on what’s left of ice. (2007). Source: https://letsgetgreen.wordpress.com/category/jokes/**

Global warming is not a new phenomenon, with the effects well documented in the latest IPCC Report (IPCC, 2013). But how damaging is warming in the polar region? The effects on cute species are well advertised (cue polar bears), but what about the effects on the less cute Arctic plant communities?

Getting Greener

A common belief is that plant communities are able to adapt to warmer temperatures and altered cloud cover and increase photosynthesis, as seen in Toolik, Arctic Alaska, where a study found significant warming effects and environmental changes in the vegetation community over several decades (Hobbie et al., 2017), including higher plant biomass and satellite Normalised Difference Vegetation Index (NDVI-determines from satellite imagery if there is live vegetation in the study site).

The increasing temperatures also indirectly affected the Arctic vegetation through warming of the permafrost 20m below the surface which resulted in melting and erosion of previously frozen soil, leaving more thawed soil cover for plants to colonise (Hobbie et al., 2017).

Gassy Greens

The smell of pine needles is from a chemical called monoterpenes which vaporises easily to attract pollinators. Available at: http://instaar.colorado.edu/outreach/trees-and-vocs/ — ***The smell of pine needles is from a chemical called monoterpenes which vaporises easily to attract pollinators. Source: http://instaar.colorado.edu/outreach/trees-and-vocs/***

Most plants, such as pine trees, emit “biogenic volatile organic compounds (BVOCs)”: gases that can contribute to atmospheric aerosol formation (Kramshøj et al., 2016). BVOCs are dependent on temperature and light and arctic emissions are expected to be affected by increasingly higher temperatures, changing cloud cover and changing vegetation composition (Kramshøj et al., 2016). In fact, warming caused a 260% increase in total arctic ecosystem emissions, including a 90% increase solely from plants (Kramshøj et al., 2016)!

The composition of the vegetation in the arctic is changing, with a shift towards more shrubs, pines and other tall, dense, gassy BVOC vegetation (Makoto et al., 2015). As expected, many animals that rely on Tundra vegetation (lichens, mosses, grasses) for food, shelter and breeding grounds are being squeezed into the remaining pockets of shrinking Tundra, and are unfortunately dwindling in population numbers as a result. Sadly, the most likely consequence of this shift is a devastating total ecosystem collapse (ACIA, 2004).

Contrast between ever increasing vegetation cover and ever decreasing snow cover. Available at: http://www.galenfrysinger.com/nunavut_canada.htm — ***Contrast between ever increasing vegetation cover and ever decreasing snow cover. Source: http://www.galenfrysinger.com/nunavut_canada.htm***

As well as altering the biodiversity in the ecosystem, warming also alters physical processes that occur in the Arctic, particularly surface albedo (reflection of sunlight and radiation against the snow). As the snow melts, the NDVI increases so less energy can be reflected back to space, meaning surface temperatures continue to increase in a negative loop (Euskirchen et al., 2016).

Warming isn’t good.

It makes the existing vegetation emit harmful gasses and chemicals that contribute to more warming, and invites more forest suited vegetation into the ecosystem and completely changes it, making thousands of pre-existing animals homeless and without food.

But it isn’t all doom and gloom (yet). Advanced technologies providing climate data are helping educate people on the importance of reducing their emissions that contribute to the greenhouse effect and global warming and the impacts they are having on the rest of the world, encouraging the public to adapt their actions to ways that are more planet friendly.

Because after all, who wants to be responsible for the disappearance of all the cute Arctic animals? (And plants)

http://www.greenfacts.org/en/arctic-climate-change/l-3/4-arctic-tundra.htm

References

ACIA (2004). Impacts of a Warming Arctic: Arctic Climate Impact Assessment. Cambridge University Press.

Euskirchen, E., Bennett, A., Breen, A., Genet, H., Lindgren, M., Kurkowski, T., McGuire, A. and Rupp, T. (2016). Consequences of changes in vegetation and snow cover for climate feedbacks in Alaska and northwest Canada. Environmental Research Letters, 11(10), p.105003.

Hobbie, J., Shaver, G., Rastetter, E., Cherry, J., Goetz, S., Guay, K., Gould, W. and Kling, G. (2017). Ecosystem responses to climate change at a Low Arctic and a High Arctic long-term research site. Ambio, 46(S1), pp.160-173.

IPCC (2013). Summary for Policymakers. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Kramshøj, M., Vedel-Petersen, I., Schollert, M., Rinnan, Å., Nymand, J., Ro-Poulsen, H. and Rinnan, R. (2016). Large increases in Arctic biogenic volatile emissions are a direct effect of warming. Nature Geoscience, 9(5), pp.349-352.

Makoto, K., Bryanin, S., Lisovsky, V., Kushida, K. and Wada, N. (2015). Dwarf pine invasion in an alpine tundra of discontinuous permafrost area: effects on fine root and soil carbon dynamics. Trees, 30(2), pp.431-439.

Word Count: 500

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Gassy Greens and Growing Veg: the hotter future of the Arctic

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