THE ORIGINS EARTH
The Whitsundays Islands
The Whitsundays are a group of 74 islands situated on the coast of the Queensland in Australia and are part of the Great Barrier Reef World Heritage Area. There are 6 national parks among which there is Whitsundays Islands National Park where there is the famous Whitehaven beach, the most photographed-beach.
The Whitsundays’ name is coming from the British James Cook who discovered those islands, a day of Pentecost.
Those islands have been the home of Ngaro’s tribute that was aboriginal people of this area who have lived for at least 9000 years. Their occupation has been revealed due to stones axes and cutting tools found on South Molle Island.
Originally, those islands were a volcanic mountain range links to the continent where volcanic activity continued for 37 million years. Those islands are continental’s islands that were part of the continent of Australia and the Whitsundays we see today were part of a mainland mountain range that was separated from the mainland a number of times due to ices ages, sea levels (low and high tides) over millions of years. But 10’000 years ago, at the end of the last ice age, the most recent change happened due to glaciers melting. Indeed, with this reason, Coral Sea rose over the coastal plain and left only mountain-tops and the rock ridges that we see today on Whitsundays.
Being on the same latitude as Tahiti in the northern hemisphere and Mauritius or Rio de Janeiro in the southern hemisphere, the archipelago of Whitsundays has a tropical climate. The temperature’s average is around 27.4C° and may rise until 30 degrees while summer temperatures from December to February. As many of tropic islands, the Whitsundays have a form of brief tropical showers. The maximum temperatures in winter from June to August are around 24-25 degrees.
Among plants of Whitsundays islands, Coastal she-oak, hoop pines, eucalyptus, grass trees, mangroves, native hibiscus, orchids, and seagrasses can be found. Soils, exposition to elements and availability of fresh water are the main factors for their growth.
They are found on Withsundays islands is from Myrtaceae family and is from Australia so are indigenous of the Australian continent. Eucalyptus plants dominate 95% of forests. Most of the species like E.globulus have been added in Europe on Mediterranean coastlines, also planted in Northern Africa (Morocco, Algeria, Tunisia, and Libya). On Madagascar Island, they can be also found, in Mayotte, Reunion Island, and Southern Africa and many more other places in the world.
Eucalyptus may measure between 10 to 30 metres and up to 90 metres in their adult size. Most of the eucalyptus species have persistent leaves but few species lose them at the end of the dry season.
Eucalyptus leaves are covered with oil glands, which gives essential oil. On mature eucalyptus leaves are mainly lanceolate, petiolate, and alternate.
How to recognize eucalyptus species? By its flowers and fruits. Flowers have numerous and different colourful stamens, which can be cream, white, yellow, pink or red and are enclosed in a cap known as the operculum. However, flowers have no petals.
The bark is very useful in order to recognize species because it can have many differences with its appearance such as a fibrous, hard, or smooth bark. Barks can also have an incredible function like with E.globulus species. Indeed, bark cells are able to do photosynthesis while there is no foliage.
Grasstree is a common name for Xanthorrhoea species, which is coming from Australia. This plant is a monocot, which means they only have one cotyledon. They are growing on nutrient-poor soils and some of the species are very slow growing. They may reach 6 metres tall with a growing about 0.8 cm to 6cm per year. Grasse tree leaves are narrow, linear and stiff and form a « skirt » around the base of the trunk. Time indication of the last fire is seen due to the length of the skirt. Indeed, the longer the skirt is the longer the duration without fire is. Certain grass trees regenerate after a bushfire by producing a large number of flowers but may take many years to flower and, however, not all species of grass trees are fire-tolerant.
Undersoil there is an impressive root system where mycorrhiza (also called fungus) surrounded the roots in a symbiotic relationship that helps the plant take up nutrients.
Grass trees are found on the east and west coast in Australia. This is an endangered species especially the Shinny Grass Tree that is about to be assessed by the IUCN Red List of Threatened Species with the Sand Grass Tree that is considered vulnerable to extinction. Many species of grass tree have been devastated by cinnamon fungus.
Kingdom > Plantae
Family > Zosteraceae
This plant is part of a group of plants called monocotyledons and is living under the water and their roots and rhizomes sink into the sediment of the seafloor for absorbing nutrients. Seagrasses have 72 species and can be named like eelgrass, turtle grass, tape grass, shoal grass, and spoon grass reflecting their role in marine ecosystems. They are growing in salty waters with high light for photosynthesis and in a depth of 1 to 3 meters. Antartica is the only continent where there are no seagrasses in its waters.
This plant grows both vertically and horizontally to capture sunlight and nutrients from the water and sediments. Asexual clonal growth and sexual reproduction are two methods used by this plant. Indeed, asexual clonal growth is necessary for enlarge a network in order to spread into sediments and create new shoots. This is the horizontal growth and for the other one (vertical growth) this is the sexual reproduction, which is the same as terrestrial grasses but pollinisation is helped by water. How does it work? Male seagrasses release pollens from stamens into the water then stamens move thanks to currents and when they meet a female flower there is pollinisation of pistil and fertilization takes place. There exists self-pollinisation but with this pollinisation genetic variation may be reduced.
Seagrasses have a particularity, which modifies their environment by creating new habitats that have important effects on other animals. It takes an important role in commercial fisheries and biodiversity by cleaning the surrounding water and helping take carbon dioxide out of the atmosphere. Indeed, one square meter of seagrass can generate 10L of oxygen every day thanks to photosynthesis. Seagrasses leave absorb nutrients, capture dirt and cut particles. In some poor regions, seagrass plants help nutrients by taking up from the soil and releasing them into the water thanks to their leaves.
Seagrasses are also nursery habitats because they provide shelter for invertebrates (shrimps, crabs), small fishes and other species of fishes. Furthermore, they are important feeding grounds for many species around the world like green turtles, manatees, dugongs, and geese.
Seagrasses are vulnerable to physical disturbances such as waves and storms. Furthermore, some animals are destroying the rhizomes and the roots of this plant while they are searching for food. The human activities are part of the losses of this seagrass bed such as fertilizers and pollution blocking sunlight, which is necessary for their growth. Dredging is also a cause of their loss because of the lack of light and an increase of sediments in the water. Boat anchors and propellers are another factor of this loss fragmenting the habitat because it may increase erosion. Disease, temperature, removal of fish, and invasive seaweed may devastate seagrasses as well.
Birds are the main animals living on the Whitsundays Islands but others species are part of this ecosystem such as wallabies, kangaroos, black flying-foxes, turtles and whales. In the insect’s world, there are ants and spiders.
We will meet those incredible animals in other posts with more details and issues concerning them.
Lanceolate: Leaves are long, wider in the middle, shaped like a lance tip.
Petiolate: This is a leaf with a petiole.
Petiole: This is a piece that attaches the leaf to the stem.
Monocotyledon: Plants with a single cotyledon.
Cotyledon: This is the embryo within the seed of a plant to give a primary leaf
Where: Airlie Beach – Queensland
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Nature fascinates me and calls out to me in every nook and cranny. Curious, I want to understand how it works and the interactions that play out between different species and ecosystems.
Thanks to the trips I have made so far, I have realised that my interest lies in the protection of the environment and in that of animals.
I observe it and immortalize it in order to make people aware that through the beauty it gives off, it has an important part of fragility that must be taken into account to be protected.
So to make people aware but also for concrete actions to be taken, I decided to create The Origins Earth.Géraldine
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