The University of Southampton

Tag: Biodiversity

Why those holiday snaps may never look the same again….

Posted on by Lauren Scrace

From Sunday night Attenborough documentaries, to gap year photos from people you haven’t seen for years, we’re becoming increasingly informed about the world around us, enticing us to explore.

The Great Barrier Reef stretching the Queensland coastline is such a vast natural spectacle it can be seen from space. This complex ecosystem is home to over 450 types of coral and provides a habitat for marine creatures ranging from tropical fish to turtles (1), making it a popular holiday destination but for how much longer?

Lizard Island, Luxury Lodges of Australia, Queensland
Unbleached Coral reef community. Queensland (2)

This beautiful system is under threat from rising sea temperatures, putting stress upon the corals causing them to release the algae from their tissues leaving only ghostly white calcium skeletons remaining. Both the coral and the algae rely on their partnership for energy and safety.

These ‘bleached’ corals are unsustainable and will perish within weeks if the sea temperature fails to return to within tolerable ranges. Due to the certainty of rising ocean temperatures, restoration success is unlikely and the devastation likely to continue. (1)

Once a year the reef engages in mass reproduction, triggered by temperature and the lunar cycle, this supports continued reef biodiversity as well as providing an ample source of food for reef dwellers. A shift in the temperature cues for reproduction will have severe impacts on community biodiversity as compared to natural incidents global shifts cause a greater long term impact, reducing the possibility of recovery (3).

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Coral bleaching event. Picture credit- The Ocean Agency / XL Catlin Seaview Survey / Richard Vevers  (4)

Environmental change that impacts the structure of the corals will also affect their functional ability within the community. (5) Corals provide shelter for many marine species, allow for protected migration and increased genetic flow through coral corridors.  This change alter the community structure and exasperate the global mass extinction we are currently experiencing.

So what is actually happening?

Global activities are impacting the future of this system dramatically, through climate change and our ever-increasing carbon footprint.

Corals extract calcium carbonate (the substance that forms eggshells) from the surrounding sea water to build the reef, using energy utilized from the algae within their structures. Each species builds differently to give beautifully diverse reefs, supporting creatures from zooplankton to green turtles.

Increasing atmospheric CO2, is absorbed by the oceans where its combined with seawater to produce an acid, leading to ocean acidification. This reduces the concentration of carbonate ions available for use by the corals to build their structures. (6)

These global changes aren’t the only driver of community shifts. On a local scale, flooding in Queensland has caused sediment and pesticide run off into the oceans. This increased nutrient input is devastating to a system reliant on diversity (7,8),  where some species are more susceptible to change than others, causing a decline in both population density and biodiversity.

So our holiday snaps might never look the same again… To mitigate this change we need to alter our way of life, just travelling to see them impacts their survival! But keep snapping and keep people talking, its the only way we are going to make change!

 

5.8 tonnes of CO2 is released per person during a flight from London to Darwin Australia!! 
Flight # Details: Tonnes CO2
1 Return From London Gatwick to Darwin Australia 1 passenger 5.8

 

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References

  1. Australia’s Coral Reefs under Threat from Climate Change by Lesley Hughes, Will Steffen and Martin Rice (Climate Council of Australia).
  2. Great Barrier Reef | Australia’s Great Natural Wonder”. Great Barrier Reef. (2017). 21 Mar. 2017.
  3. Nyström, M., Folke, C., & Moberg, F. (2000). Coral reef disturbance and resilience in a human-dominated environment.Trends in Ecology & Evolution, 15(10), 413-417.
  4. The Ocean Agency. 2016. THE 3RD GLOBAL CORAL BLEACHING EVENT – 2014/2017. Available at: http://www.globalcoralbleaching.org/#essential-facts. [Accessed 21 March 2017].
  5. Richmond, R. H. (1993). Coral reefs: present problems and future concerns resulting from anthropogenic disturbance.American Zoologist, 33(6), 524-536.
  6. Hoegh-Guldberg, O., Mumby, P. J., Hooten, A. J., Steneck, R. S., Greenfield, P., Gomez, E., & Knowlton, N. (2007). Coral reefs under rapid climate change and ocean acidification.science, 318(5857), 1737-1742.
  7. Mongin, M., Baird, M. E., Tilbrook, B., Matear, R. J., Lenton, A., Herzfeld, M., & Duarte, C. M. (2016). The exposure of the Great Barrier Reef to ocean acidification.Nature communications, 7.
  8. Dubinsky, Z. V. Y., & Stambler, N. (1996). Marine pollution and coral reefs.Global change biology, 2(6), 511-526.


Addressing the Elephant in the Room: A look into the Global Loss of Megafauna

Posted on by Julia Daly

In the light of the current epoch, the Anthropocene, being classified as a sixth mass extinction (Pievani, 2014), losses in biodiversity and its effects on ecosystems, from which humans directly benefit, has had a lot of scientific attention (Diaz et al., 2006). However, only recently has there been a focus on the global loss of terrestrial megafauna; larger bodied mammals of mass greater than 1000kgs (Ripple et al., 2015). In March 2014, the University of Oxford hosted the first ever international conference on ‘Megafauna and Ecosystem Functions’ (Malhi and Doughty, 2015) to address this global issue. Terrestrial megafauna, are under threat from human caused habitat loss and fragmentation (Segan et al., 2016), due to land-use change, such as agricultural expansion and deforestation (Ripple et al., 2015, 2016). Although this is a global issue, the heaviest decline in megafauna is concentrated in sub-saharan African and south-east Asia (Figure 1).

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Figure 1– Global representation of the number of declining megafauna worldwide (Ripple et al., 2016)

Environmental change through the alteration of habitats puts the larger sized megafauna at a higher risk of extinction as they need larger, non-fragmented habitats, and have slower life-histories (Ripple et al., 2016), taking longer to reproduce.

Why focus on megafauna? Extensive research into losses of biodiversity and its effect on ecosystems has revealed one thing for certain: the importance of functional traits. Biodiversity can ensure the functioning of an ecosystem if its functional composition is adequate to maintain the system, having organisms with specific traits (Diaz, et al., 2006). Much like a well-working machine, all the pieces are needed for it to run. The more important parts of this machine, or ecosystem, are the megafauna, as many act as ecosystem engineers (Smith et al., 2015) and keystone species (Ripple et al, 2016). Megafauna fill the roles- niches- in the ecosystem that would otherwise not be filled. The effect of their loss will be felt by the whole ecosystem as impacts will filter down through trophic levels and the food web (Svenning et al., 2015).

The African elephant alters ecosystem structure and composition, through various behaviour including uprooting and debarking of trees (Mograbi et al., 2017), seed dispersal and alteration of habitats (Ripple et al, 2015). They have overall effects on the ecosystem in which they live, which indirectly affects the other organisms that depend on that ecosystem (Figure 2). Land-use change has caused a decline in African elephants (Ripple et al., 2015); a key player in ecosystem functioning. The ecosystem may therefore begin to fall apart without it’s key piece (Smith et al., 2015). This is just one example of how the loss of a single species can have significant implications, highlighting the severity of impacts if several species were to be lost.

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Figure 2– Diagram demonstrating how the African elephant can effect the ecosystem and the other organisms they impact (Ripple, et al., 2015).

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Figure 3 – Diagram and explanation of the interactions between global changes, human activities and ecosystems (Chapin III, et al., 2000).

These global changes can be felt not only by the animals, that depend on the megafauna, but by humans as well. Figure 3 shows how humans will also ultimately feel the effects of the global changes they cause due to their effects on ecosystems.

 

 

References:

Chapin III, F. S., Zavaleta, E. S., Eviner, V. T., Naylor, R. L., Vitousek, P. M., Reynolds, H. L., Hooper, D. U., Lavorel, S., Sala, O. E., Hobbie, S. E., Mack, M. C., Diaz, S., 2000. Consequesnce of changing biodiversity. Nature 405, pp 234-242.

Diaz, S., Fargione, J., Chapin III, F. S., Tilman, D., 2006. Biodiversity Loss Threatens Human Well-Being. PLoS Biol 4(8): e277

Malhi and Doughty, 2015. Megafauana and Ecosytem Function: Learning from the Giants. Available at < http://www.eci.ox.ac.uk/news/2015/1026-megafauna.html> [Accessed: 21st March 2017]

Morgabi, P., Asner, G. P., Witkowski, E. T. F., Erasmus, B. F. N., Wessels, K. J., Mathieu, R., Vaughn, N. R., 2017. Humans and elephants as treefall drivers in African savannas. Ecography 40: 001-011

Pievani, T., 2014. The sixth mass extincton: Anthropocene and the human impact on biodiversity. Rend. Fis. Acc. Lincei 25: 85-93

Ripple, W. J., Newsome, T. M., Wolf, C., Dirzo, R., Eceratt, K. T., Galetti, M., Hayward, M. W., Kerley, G.I.H., Levi T., Lindsey, P. A., Macdonald, D. W., Malhi, Y., Painter, L. E., Sandom, C. J., Terborgh, J & Van Valkenburgh, B, 2015. Collapse of the world’s largest herbivores. Science Advances, 1: e1400103, pp 1-12

Ripple, W. J., Chapron, G., López-Bao, J. V., Durant, S. M., Macdonald, D. W., Lindsey, P. A., Bennett, E. L., Beschta, R. L., Bruskotter, J. T., Campos-Arceiz, A., Corlett, R. T., Darimont, C. T., Dickman, A. J., Dirzo, R., Dublin, H. T., Estes, J. A., Everatt, K. T., Galetti, M., Goswami, V. R., Hayward, M. W., Hedges, S., Hoffmann, M., Hunter, L. T. B., Kerley, G. I. H., Letnic, M., Levi, T., Maisels, F., Morrison, J. C., Nelson, M. P., Newsome, T. M., Painter, L., Pringle, R. M., Sandom, C. J., Terborgh, J., Treves, A., Van Valkenburgh, B., Vucetich, J. A., Wirsing, A. J., Wallach, A. D., Wolf, C., Woodroffe, R., Young, H. and Zhang, L., 2016. Saving the World’s Terrestrial Megafauna. BioScience, 60 : 10, pp 807-812

Segan, D., B, Murray, K. A., Watson, J. E. M., 2016. A global assessment of current and future biodiversity vulnerability to habitat loss-climate change interactions. Global Ecology and Conservation 5, pp 12-21

Smith, F. A., Doughty, C. E., Malhi, Y., Svenning, J., Terborgh, J., 2015. Megafauna in the Earth System. Ecography 39: 2, pp 99-108

Svenning et al., 2015. Science for a wilder Anthropocene: Synthesis and future directions for trophic rewilding research. PNAS 114 (4), pp 898-906

 

 

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

Posted on 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)

Read More:

http://www.amap.no/documents/doc/impacts-of-a-warming-arctic-2004/786 

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.

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