BIOL1130 Journal (2012) 1:1-6 DOI [21109527, 21137095, 20950992]
RESEARCH ARTICLE__________________________________
Climate Change Potentially Good for the Marri Tree
Christopher Bekker • Keith Henderson • Matthew Burleigh •
Abstract The purpose of this study was to research the phenomena of climate change and how it will ultimately affect the Corymba calophylla (Marri tree), and subsequently affect other species of wild life as well. This involved locating information on other similar studies that have been conducted in the past, the finding of information on the current and predicted distribution of Marri trees, and the changes in the climate thought to have been caused by global warming. We found a variety of sources that show how the increase in the global temperature being caused by climate change may allow the Marri tree to become more widely distributed, as it will be able to thrive in areas that were previously too cold. This in turn might also help the Calyptorhynchus baudinii (Long-Billed Black-Cockatoo), whose diet consists primarily of the fruit produced by the Marri tree, to become more prominent and increase in number. This information led to the hypothesis that climate change will eventually alter the distribution of the Marri tree and as a result, directly affect other species of wildlife as well. Our research showed that climate change may not always be negative, as it seems likely that the Marri tree will become more widely distributed and the Long-Billed BlackCockatoo, which is facing extinction, may be able to repopulate. This conclusion is, however, only a prediction. Keywords – Marri, Cockatoo, Climate, Distribution, Warming, Temperature
1. Introduction “Temperatures in Australia were relatively stable from 1910 until 1950, and since then have followed an increasing trend, with an overall increase during 1910 to 2009 of approximately 0.8°C” (Australian Bureau of Statistics, 2009-10). The above quote from the Australian Bureau of Statistics helps to prove the theory of climate change which predicts a global increase in temperature over time. As such, this can have a very large affect on wild life not only in Australia, but throughout the entire world. Australia’s climate is geographically variable compared to other countries, resulting in ecosystems ranging from deserts to tropical rainforests. Whilst some parts of Australia have extremely low average rainfall, such as Alice Springs (around 270 millimetres per year), other parts of 1
the continent have very high average rainfall, such as the town of Tully in north Queensland (more than 4000 millimetres per year). This variability in climatic zones in Australia has resulted in a particularly diverse range of species, with each climatic zone having its own uniquely adapted flora and fauna (Australian Bureau of Statistics, 2009-10). This unique variability in climate zones is the main reason certain plants such as the Marri tree are distributed the way they are (see Figure 1). Corymbia calophylla (Marri tree), is present all year and generally flowers from December to May. It is most commonly found in South Western Australia and ranges from Geraldton to Albany. Due to climate change, it is expected that the plant will start shooting and flowering earlier in the year than it previously has, and it may also begin to appear in environments which were previously too cold for it (Nevill et al, 2005). The Marri tree also produces a large fruit which is commonly referred to as a “honkey nut” (City of Bunbury, nd). This fruit is considered to be a prime source of food for many species, including the Black Cockatoo. “Out of 34 foraging groups observed throughout the range of the species, 31 (91%) were seen feeding in Marri” (Saunders, 1979). Because of this dependence on the Marri tree as a primary food source, the selective removal of these trees has affected the Long-Billed BlackCockatoo in the past and continues to do so to an extent. The removal of Marri trees has largely been ceased in recent times namely due to the affect on the population of the LongBilled Black-Cockatoo which is now considered a threatened species (Garnett & Crowley, 2000). As such, it can be expected that another change in the Marri tree’s distribution and flowering cycle caused by climate change would quite similarly affect the Long-Billed BlackCockatoo. This study was conducted with the purpose of finding out exactly how climate change would affect the Marri tree; how this would affect other types of wildlife; and to draw a conclusion as to whether or not climate change would have a good or bad affect in terms of the Marri tree in Australia. The aim was to test the hypothesis that climate change would increase the distribution of the Marri tree and whether this would have a positive effect on other species. The authors predict that as the temperature increases due to climate change, the Marri tree will become increasingly more wide spread in Australia and this will result in a more definite food source for some species such as the Long-Billed Black-Cockatoo.
2. Materials and Methods Research was conducted through a variety of different mediums which included published articles concerned with either climate change, the Marri tree or Long-Billed Black-cockatoos. Searches were conducted on websites that were considered to be reliable sources of information concerning the three topics at hand. Figures and graphs were obtained to help describe and back up the statements presented throughout the article, as well as to help draw a conclusion on the hypothesis.
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The majority of the data was analysed through the writings and studies of other scientists. Graphs showing the change in temperature over time were reviewed (as is evident in Graph 1), as well as maps of Australia showing the different geographical distribution of both the Marri tree and the Long-Billed Black-Cockatoo (Figures 1 and 2). The main goal of this research was to retrieve as much accurate information as possible describing how climate change works, as well as where and how fast it is occuring in Australia. That information was then used to link what was found out about the Marri tree in terms of its growth patterns, preferred soil types, and the temperature it generally prefers to grow in. From this it was possible to develop a prediction as to how an increase in temperature due to climate change would affect the plant. It was then possible to predict the affect this would have on other certain native species in Australia, using the Long-Billed Black-Cockatoo as an example. A wide range of studies were found that came to a similar conclusion regarding the distribution of the Marri tree. It is generally predicted that as climate change begins to have a larger affect in South-Western Australia, the Marri tree will become more widely distributed. Similarly, it seems to be agreed that if there is an increase in Marri trees in Australia, the Long-Billed Black-Cockatoo will also become more widely distributed. This information was then used to draw a conclusion on the predicted affect climate change will have on both the Marri tree and the Long-Billed Black-Cockatoo.
3. Results As shown in Figure 1, there has been a clear temperature change over the last century in Australia. Before the 1980s a clear trend is observed in the temperature, with anomalies being below the expected temperature. Afterwards, however, it can be seen that most years, the temperature anomalies have been a significant amount above the expected temperature in Australia. In other words, Australia’s annual average temperature has increased by approximately 0.9 degrees Celsius (Australian Bureau of Statistics, 2010). Similarly, Figure 2 demonstrates an almost identical increase in the average temperature of Western Australia in which the Marri tree is predominantly found. The annual average temperature of Western Australia has increased by approximately 0.8 degrees Celsius since 1910 which shows that climate change has affected Western Australia in an almost identical fashion to the rest of Australia (Communicating Climate Change, 2008). Figure 3 helps to show where the greatest amount of warming has occurred within the state of Western Australia since 1950. As can be clearly seen, the areas that have experienced the greatest increase in mean temperature are those that are inland and to the southern part of the state. Evidently, the Marri tree can be found quite commonly within certain parts of Western Australia that have experienced this temperature increase as can be seen when comparing Figures 3 and 4.
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As shown in Figure 4, the Marri tree predominantly grows in South Western Australia, with the exception of a few outliers, and is very heavily concentrated in the Jarrah and Karri forests (Australian Native Plants Society (Australia), nd). However, research has shown that the Marri tree generally prefers to grow in warmer climates. From this, it can be deduced that as the temperature in Australia increases due to climate change as is evident in Figures 1 and 2, the Marri tree will start to increase in distribution and become more wide spread. As shown in Figure 5, the Long-Billed Black-Cockatoo has a very similar distribution to the Marri tree. Upon further analysis of the information collected, it was possible to verify that the Long-Billed Black-Cockatoo relies heavily on the Marri tree as one of its primary food sources (Saunders, 1974). This helps to make clear why Figures 4 and 5 are so similar. Both figures help to demonstrate a relationship between both the Marri tree and the Long-Billed Black-Cockatoo.
Figure 1 Source: Australian Bureau of Statistics, Australia’s Environment: Issues and trend (2010). Shows the Australian annual average temperatures between 1910 and 2008 (Anomalies are based on 1961 to 1990 average of 21.8ºC ). This demonstrates an increase in the average annual temperature of Australia of approximately 0.9 degrees Celsius since 1910.
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Figure 2 Source: Australian Bureau of Meteorology, Observed climate change: Western Australia (2008). Shows the Western Australian annual average temperatures between 1910 and 2008 (Anomalies are based on 1961 to 1990 average of 21.8 ยบC). This demonstrates an increase in the average annual temperature of Australia of approximately 0.8 ยบC since 1910. (Red=above average, blue=below average)
Figure 3 Source: Australian Bureau of Meteorology, Observed climate change: Western Australia (2008). Shows the mean temperatures (ยบC) in Western Australia since 1950. As can be seen, the area that has experienced the greatest temperature increase is inland South Western Australia.
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Figure 4 Source: Atlas of living Australia. This figure shows the current distribution of the Marri tree in Australia. As can be seen, the Marri tree is almost exclusively native to the South Western part of Australia. As climate change continues, it is predicted that this distribution will increase and begin to cover a larger area of the map.
Figure 5 Source: Department of Sustainability, Environment, Water, Population and Communities. This shows the current distribution of the Long-Billed Black-Cockatoo throughout Australia. As can be seen, it has a very similar distribution to the Marri tree and this is due to the Marri tree being the producer of one of the Long-Billed Black-Cockatoo’s main food sources. As such, as the distribution of the Marri tree changes, it is expected that the Long-Billed Black-Cockatoo will follow a similar pattern.
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4. Discussion When all of these results are considered together there seems to be numerous reasons to believe that an increase in temperature due to climate change will increase and widen the distribution of the Marri tree, and this in turn will increase the population of the Long-Billed Black-Cockatoo. The greatest amount of warming within Western Australia seems to have occurred in the southern inland regions of the state as is made evident in Figure 3. Similarly, it was found that “daily minimum temperatures have increased more than maximums, and the most apparent warming has been during winter and spring” (Communicating Climate Change, 2008). From this information we can conclude that there is a definite increase in the temperature within Western Australia, providing evidence for climate change. This, in turn, helps to show a link between the temperature of Western Australia and the Marri tree. As you can see when comparing figures 3 and 4, the Marri tree is quite heavily located in areas that have experienced a rather large increase in temperature since 1910. From this we can predict that the Marri tree does indeed prefer warmer climates and as the temperature of Western Australia continues to increase, so too will the distribution of the Marri tree (Climate Watch, nd). This is because more areas will eventually have temperatures that are appropriate for the Marri tree to grow in. As was previously mentioned, the Long-Billed Black-Cockatoo shares a very similar distribution to the Marri tree as is shown when comparing Figures 4 and 5 and this can be linked to the fact that the fruit produced by the Marri tree is one of the bird’s most common food sources (Saunders, 1974). As the Long-Billed Black-Cockatoo’s numbers are beginning to dwindle, this increase in the distribution of the Marri tree could potentially be considered a good thing for the environment (Garnett & Crowley, 2000). Effectively, it could be predicted to aid in the prevention of the Long-Billed Black-Cockatoo becoming extinct, as it could result in less competition for food amongst the species. In this sense, climate change is a positive thing as opposed to negative as it is frequently portrayed. Assuming these predictions are all correct, the hypothesis that ‘climate change will eventually alter the distribution of the Marri tree and as a result, directly affect other species of wildlife as well’ has essentially been proven to be true. Unfortunately, these results are all simply predictions based on the research conducted. At this point in time, it is too early to tell exactly what affect climate change will have on the Marri tree as the temperature increase is not quite large enough yet and research on the Marri tree has not been conducted over a long enough period of time. On that note, the hypothesis cannot be answered with any definite certainty at this point in time, however, future studies conducted on this very topic will likely be able to draw a steadfast conclusion on the hypothesis with the help of statistics and research provided by previous scientists before, after and during this time. Acknowledgements Thank you to the following websites for making it much easier to analyse the distribution of the Marri tree, Long-Billed Black-Cockatoo and climate change: ClimateWatch, the Atlas of Living Australia, and the Australian Bureau of Meteorology. Similarly, a special thanks to Marcin Falkowski for editing and reviewing our work.
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References Atlas of Living Australia (nd). Corymbia calophylla. http://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:apni.taxon:304834\
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