Category: Wet Tropics Ecology & Conservation

Koala Population on Magnetic Island, Conservation Status, and Physiology

Koala Physiology and Behavior by Kunal Thakur

The koala, phascolarctos cinereus, is a species which can only be found in Australia and is part of the marsupial family which give birth to undeveloped young which climb onto the pouch and latch on to the teat until complete development. As an arboreal marsupial herbivore, the animal lives in Eucalypt forests along the Eastern region of Australia including Queensland, New South Wales, Victoria, and South Australia. Descending from a group of much bigger animals in the Australian environment, the koala is the only remaining member of the Phascolarctidae family with its closest relatives being the wombats.  In order to survive, the koala has evolved specifically to become the only mammal that can survive on leaves of the Eucalyptus tree alone. Because of the low energy and nutrient output that the Eucalyptus tree leaves provide, the koala has had to evolve several physiological and behavioral traits in order to successfully use the tree as a source of food. In order to make the most of the food source, the Koalas only eat from 10% of the 600 different species of the Eucalyptus tree with an even stronger preference of only 5% to maximize the number of nutrients which can be obtained as some species of the tree are more nourishing than others. The leaves of the specific species are chosen for their protein content and low indigestible fiber and lignin amounts. The koala has also evolved a liver which works to isolate and excrete the toxins which make the Eucalyptus tree indigestible for other animals. With an extremely long digestive process, the koalas use hindgut fermenters and long caecum with specific bacteria to digest the fiber of the Eucalyptus tree. To raise the young, the koala mothers must make a “pap” which consists of a mixture of milk and tree leaves to feed the koala young to make sure they become used to toxins and bacteria which comes with the Eucalyptus leaves. Behavior and lifestyle of the Koala has also been adapted to their diet. Because of the lack of nutrients of the leaves of the Eucalyptus tree, the koalas follow a low energy diet and can spend up to 21 hours a day resting. Their brain has evolved to become much smaller to conserve energy for the animal and this causes the species to have no complex communication and live in solitude not doing much other than eating and sleeping. There can be no extended maternal care because of the energy required to take care of the young and the mother will leave as soon as the developing koalas can eat the leaves of the Eucalyptus tree. With curved, sharp claws and opposable digits, the koala is well adapted to climb trees and also grasp branches on the Eucalypt. The animal has incisors and cheek teeth which allow for it to take in leaves and cut and grind the leaves down which leads to better digestion. As the koala has evolved very specifically to match its niche diet of Eucalyptus tree leaves, the animal does not have many other ecological interactions. The koala has few natural predators as it spends most of its life up in the high branches of the Eucalyptus trees and also does not perform any other role in the Australian ecosystem. By fitting into a very specialized role through repeated evolution, the koala has eliminated its ecological role in the Australian environment.

A Wild Koala on Magnetic Island

Koala Conservation by Lin Cao

Found exclusively in Australia, koalas have become an icon for the country and its unique wildlife. They are under federal protection, and it is illegal to hunt and kill koalas. However, they are under pressure from many other threats, and their populations have crashed by up to 80% in certain urban areas.

Though koalas are protected, their habitats are not. Habitat fragmentation is a major issue, and as development projects force koalas into smaller areas, stress and overcrowding have caused additional problems. Chlamydia easily spreads among tightly packed individuals, and the disease eventually leaves individuals blind and vulnerable to many other dangers. Deaths from car collisions and encounters with dogs and cats also increase as contact between koalas and humans increases. Another hazard for koalas is high intensity fires. After a long period of fire suppression in Australia, many areas of eucalypt forest have high amounts of unburned fuel left, and accidental or sudden fires may flare out of control and kill koalas who are unable to escape. Climate change represents a major challenge for koalas. Koalas exclusively eat eucalyptus leaves, which are quite nutrient poor. They consume massive amounts of leaves each day to acquire nitrogen for amino acid and protein synthesis, and the leaves also provide a source of water. However, climate change has created a shift in eucalyptus leaf content. Nitrogen levels are decreasing while carbon levels increase. Water content has also decreased. Both of these changes place additional pressures on koalas and their current feeding habits.

With the challenges they are facing, koala conservation has come under the spotlight and generated a few debates. Koalas play no ecological role. For instance, they have few natural predators and do not help propagate any plants. Much of the push for koala conservation comes from public sentiment for koalas as an icon for Australia rather. However, some wonder if there has been too much of a focus on iconic or charismatic species like koalas when there are much more vulnerable or important species. For instance, termites play an important ecological role in Australia and are facing challenges as humans brand them as pests and work to eradicate them, but there are few efforts to protect them or increase awareness of their importance. In contrast, there are many koala advocacy and conservation groups, and much of the general public has some knowledge about koalas. Though the debate rages on, one potential role for the koala is as an ambassador species. Certain organizations use more iconic animals to engage the general public and then use that engagement to promote other species. Koala conservation can also have umbrella effects. To save a koala, a eucalyptus forest has to be saved, and other species dependent on that forest may be saved as well. Koala conservation is also a good idea from an economic standpoint. Koala-related tourism is an important source of revenue, and estimated expenditure on zoo visits, koala photos, and koala souvenirs is nearly $336 million per annum. Finally, some argue that koalas should be conserved because only human error has caused their populations to decline. They came to exist in Australia and it is only fair to preserve their natural status. While there is some debate around koala conservation, it is clear that as koala populations continue to respond to environmental pressures, koala management attitudes strategies will have to adapt as well.

 

 

Koala Population Field Work by Ben Lasley

 

Today we worked with Jules from the Billabong Sanctuary and Rachel from the Koala Park to continue research that James Cook University started on Koala populations on Magnetic Island. After breakfast, we biked to the first of the two sites and learned about the ongoing experiment and the procedures. The fifteen were split into three teams of five, with four in each team designated as collectors and one designated as the “sniffer” for the team. The sniffer was tasked with differentiating old koala scat from new koala scat. The new koala scat, which is up to 57 days old, smelled faintly of eucalyptus leaves, whereas the old scat, greater than 57 days, was odorless. The different teams laid out fifty meter by 1.9 meter transects through the bush by attaching rope to a beginning point, like a tree, and measuring 50 meters onward. The width was controlled by a 1.9 meter stick that was split evenly so that .95 meters was on either side of the rope. Two teams of two started on both sides of the 50 meters and were given gloves and miniature rakes to comb through the underbrush.

The teams were advised on the threat of death adders and taught the procedures if someone was bitten by a snake. The three teams were given one hour to hopefully finish the transect and quantify the number of old and new scat. As the teams would comb through the scat, the sniffers would be behind them going through the retrieval bags and sorting the koala scat into old and new bags. Additionally, collectors would occasionally pick up misshaped scat, only to discover that it was wallaby scat. The wallaby scat definitely did not smell of eucalyptus leaves. As the teams progressed throughout the transects, they encountered ferocious green ants and when their nests were slightly disturbed, they poured out and bit numerous people.

Another component of the transect was the identification of different trees within the various transects. While one group only had Morleton Grey Ash and Popular Gum trees, other groups had Red Gum Eucalyptus trees, which are the favorite food of the koalas. At the end of the hour, two groups had finished, while the other group had sixteen meters left in the transect. As the three groups complied the number of scats, one group only had 190 koala scats, while the other two groups had over 400 koala scats each. This was attributed to the various species in the transect, with one transect having a large and mature Red Gum, the favorite of koalas.

After cleaning up the site, the group biked to a koala hotspot. They were able to see a total of 6 Koalas, including a mother and her joey, two solitary koalas, and a mother and offspring pair that had recently split off. After returning to the hostel, the data was interpreted and explained to the team. The data would be compiled into a spreadsheet and then fed into several equations to determine the population of koalas on Magnetic Island and the migration patterns depending on the season. The field work was dirty and sometimes smelly, but the experience was worth it.

A Look at Koala Population Studies on Magnetic Island

 

By Danny Oh

 

On July 2nd, the UNC Study Abroad group went to an open mixed eucalyptus forest to assist in koala population size studies. We helped Jules Funnell, a ranger at the Billabong Sanctuary, perform the fecal standing crop method for estimating the population size of koalas at the site. This was part of James Cook University’s initiative in beginning a long-term population study of koalas on Magnetic Island. The study began last year, and since then, there have been several ecotourism groups that have contributed to the growing dataset.

 

Koalas did not previously exist on Magnetic Island: European colonization of mainland Australia led to the development of the koala fur trade. By 1924, Koalas were extinct in South Australia, and the fur trade had moved up to Queensland. In 1919, the QLD government announced a 6-month open season on koalas, and one million koalas were killed in that season alone. In 1927, the season reopened and over 800,000 koalas were killed within one month. Public outrage led the government to declare koalas a “protected species”, and koalas were introduced on islands, such as Kangaroo Island and Magnetic Island, as insurance populations in the late 1930s. Although they provide no ecological role within the ecosystem, they are valued highly within the ecotourism industry, bringing in a A $3.2 billion profit annually and 30,000 jobs. Koala population studies have been implemented in several states of mainland Australia, and the populations were carefully monitored every several years. However, no one knew exactly what the koala population size was on Magnetic Island.

 

In 2011, McGregor et. al. did the first koala population studies on Magnetic Island in the peer reviewed article, The Distribution and Abundance of an Island Population of Koalas (Phascolarctos cinereus) in the Far North of Their Geographic Range. They performed the Fecal Standing Crop Method (FSCM), where they used GPS designated points along with 100 m transects and collected koala scat. The scat was then separated based on smell of eucalyptus: the new scat retained the smell of eucalyptus (smell lingered for approximately 57 days) while the old scat lost its smell. In the article, 285 transects were analyzed over a time period of 656 hours. The FSCM was validated in a previously published article by CSIRO, and it is favored due to the solitary lifestyle of koalas. They estimated between 800 to 900 koalas on the island today.

 

It is difficult to estimate the koala populations from the UNC studies. Unfortunately, we do not have the literature that goes into the mathematics in translating scat counts to koala population size. However, we do see the merits of the research: the McGregor 2011 paper did not collect data in disturbed urban areas, which is where we collected scat. The population trends of koalas in urban areas could be valuable in determining their resiliency with encroaching urbanization. In addition, this data is still at its initial steps, since only two years of data have been collected so far. Population dynamics studies use data sets that are collected over a long time. The data set can then be used to observe seasonal variation and population trends of koala population size on Magnetic Island.

Even though we couldn’t really get the actual koala population size, we felt that we had made a great contribution in a growing data set for future groups visiting Magnetic Island. Though the koalas do not provide an ecological role, I did witness their value in the ecotourism industry: I got my picture taken with Claudia at Bungalow Bay Koala Village, and it really is something I will cherish from this trip.

Learn more about McGregor’s koala population study:

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0059713

Caption: This shows the koala habitats that are projected to disappear within the next half century due to urbanization of coastal areas of East Australia.

This figure from the McGregor 2011 article shows the koala density across Magnetic Island determined using the fecal standing crop method.

Adaptions and Topography of Australia

By: Despina Giotis and Rebekah Appleton

Despite being comparable in size to the United States, Australia has considerably less people. This is because 70% of Australia is arid land but it is still very unique in organism diversity and landscape. Some of the landscapes include grasslands, rainforests mangroves and, of course, The Great Barrier Reef. Many arid areas have temporary rivers and have lower levels of nutrients in the soil, while grasslands have more plants, composed of mostly grasses and small shrubs with a range of marsupials. Unlike the other landscapes, Rainforests get lots of rain and have dense canopies with large trees and support a large population of birds and mammals. Along the coast there are also bioregions that increase the aquatic diversity of Australia. Mangroves are able to survive in high salinity water which allows for them to survive in marine ecosystems. One of the more well-known bioregions for Australia is The Great Barrier Reef which is incredibly diverse in the marine life that it supports, such as the corals that make up the coral reef. Queensland alone has about 15 different bioregions with the Brigalow belt being the largest bioregion, named for the common Brigalow Acacia which survives in low soil nutrient levels. Since Australia is also incredibly close to Antarctica, the South is known for having cold wet winters, which could receive large amounts of snow, and hot dry summers. The North has warmer drier winters and wetter summers.

Australia gained a lot of this unique diversity due to years of isolation as an island, however, Australia was not always isolated. Australia used to be a part of a large group of continents and countries called Gondwana around 170 million years ago. Gondwana was made of India, Australia, Antarctica, South America, and Africa and a few assortments of countries. Fossils of a specific fern, Glossiopteris, are found on all 7 of the mentioned land masses which is how scientists determine that these countries used to be connected. Around 80 million years ago Australia was still connected to Antarctica and South America and shares commn plants such as Eucalypts. Overtime the diversity of Australia has changed. Australia once contained many species of Megafauna some that could have been related to current species such as the koala. The Megafuana has since gone extinct maybe due to pressures such as hunting. In 1788 white settlers began settling in Australia, which caused many changes in the local landscapes and organisms. Hunting not only caused the extinction of the Megafuana, but the addition of the settlers hunting caused the extinction of species such as the Thylacine which was a marsupial tiger. The loss of these orgasms causes a huge loss in diversity of very unique animals. The Thylacine, for example, was the last of the predatory marsupials and many of Australia’s organisms face the same threat such as the koala that was hunted for its fur. The white settlers also introduced animals such as cats and foxes which were intelligent predators and were particularly skilled at catching the local wildlife. Many of the local organisms cannot adapt to these quick changes in survivability.

Before the settlers, the natives were particularly helpful in protecting and controlling the land through fire and care. The settlers, however, caused even more changes in the landscape. The settlers not only began land clearing for cattle farming but they also neglected the landscape’s natural need for controlled fire. This caused the loss of large amount of mangrove systems and loss of habitat such as the fire resistant landscape of the sugar glider. Recently, people have rediscovered the need for fire and reintroduced that aspect to the landscape, however, now they are facing problems with pollution and energy use. Since then, many areas of Australia has been deemed a national park such as Magnetic Island. These protected areas are vital to the future of Australia’s organisms and with increased protection, Australia hope to see some of the damage mitigated in the future.

Aside from rainforests and the mountain vegetation of the east, most plants in Australia must be adapted to dry conditions and have the ability to deal with water stress. The soil is often made of clay and is low in nutrients. Specifically, Magnetic Island is considered a dry tropical region and has a warm dry season, which is known as the winter, and a hot wet season, which is known as the summer. Magnetic Island’s soil has even less nutrients and is made of sand like pieces of broken off sedimentary granite, therefore it does not hold water very well. Once the ground is socked the sandy sediment is carried away with runoff water, making erosion a prominent issue. The plants in this region are brightly colored and have scents in order to attract birds and insects for pollination. The plants depend on different combinations of wind, water, and fire dispersal methods. They often have thickened plant cuticles and low numbers of stomata. Plant cuticles are lipid bilayers with wax incorporated into them, which create a protective film covering on the outer surfaces of vascular plants. Plant cuticles function as barriers for water permeability and aid in preventing evaporation of water. The main function of the stomata is to regulate gas exchange in vascular plants. Glucose synthesis occurs when the stomata is open because carbon dioxide enters the leaf, leading to the release of water and free oxygen. The number of stomata per unit area is labeled as stomata density; therefore the higher stomata density leads to increase uptake of carbon dioxide and increased release of water. Since water is scare in the dry terrain of Australia many of the vascular plants have decreased numbers of stomata and thickened plant cuticles in order to conserve water by decreasing excessive evaporation that may lead to desiccation. In order to be protected the most plants are armed with chemicals or spines. Magnetic Island also has numerous trees that are considered sclerophyll, which means the leaves are hard and thick. Sclerophyll forests have adapted to withstand heat, low nutrient soils and fires. Some examples of sclerophyll trees on Magnetic Island include: Eucalypts (gumtreees), Acacias (wattles), and Melaleucas (paperbacks). In order for caps to fall off and bloom Eucalypts must be exposed to fire. Likewise, Acacias have epitomic buds that only sprout after fire. Acacias also have fire resistant bark that prevents them from dying, which is why these trees tend to dominate after forest fires.

Not only have the Australian plants learned to adapt to the dry conditions, but the animals have as well. One such example is the Water Holding Frog who covers itself in a cocoon and then buries itself underground for months at a time waiting on rain. It does this in order to conserve water. Another example of an exceptional animal that uses water efficiently is the Thorny Devil. The body of the Thorny Devil is covered in spikes, which assists them in obtaining water the dry sandy parts of Australia. Early in the day they rub against spinifex, a tough, spiny grass, in order to absorb the morning dew. The moisture of the dew runs directly into their mouths through grooves that are between the spikes. There is more information about the Thorny Devil in the video that is linked below.

 

References:

https://www.esa.org/tiee/vol/v1/experiments/stomata/stomata_description.html

Billabong Sanctuary

Dingoes – Taylor Woollen

After learning the story behind Seinfeld’s “a dingo ate my baby” at Hidden Valley, we of course immediately congregated around the dingo sitting on a rock waiting to have its picture taken with you. In the Lindy Chamberlain case, dingoes are portrayed as scary creatures waiting to steal your child as soon as you turn your back on it. But at Billabong we were able to understand a different side of these dog-like animals. I, of course, had my turn taking a picture with one of the dingoes, and then pet the others when I was finished. In this case they were not baby stealing, terrifying creatures but sweet and sensitive animals. They seemed like they could be live in a home as someone’s pet even.

Many Australians do not see dingoes in this way. Even though they are located in most of the country, except Tasmania, they are seen as animals worth purging. We learned that they are similar to wolves because they form packs, they defend territories, and they can have coordinated hunting, and we learned that dingoes are quick to learn and adapt, they are neophobic (meaning they are cautious of new things), and can read human gestures. The dingo is the apex predator on mainland Australia and the largest terrestrial predator in the country. Dingoes are beneficial to their environment because they control feral animal as well as native animal populations. They prevent mesopredator release, which means that they kill and/or eat feral cats, foxes, and pigs, so these populations of invasive animals do not experience a population boom. Dingoes also control the populations of kangaroos and wallabies, and a trophic cascade is evident in ecosystems with these animals because when dingoes kill kangaroos, this increases the population of plants that kangaroos eat.

Reasons why dingoes are not seen in a positive light in Australia include conflicts with the livestock industry, people, threatened species, and hybridization. There have only been two recorded dingo attacks ending in fatality, which sheds light on the idea that dingoes are not as dangerous as they are made out to be. Even though dingoes are classified as vulnerable and native in Australia, they are also considered a pest, so they are not protected. Also landowners are legally required to kill dingoes found on their properties. Dingo management is done through baiting, trapping, shooting, fencing, guard animals, and more. Dingoes are not often found in the south east part of Australia because a large fence was built to keep them out. This fence has caused huge impacts on the rest of the ecosystem because this fence keeps out all other large animals as well. Animals dying of starvation or dehydration are not able to travel across the fence in hope of survival, so many animals such as emus have been found dead along the fence. Killing dingoes is also a tradition in Australia, which is passed down through generations. People teach their family members how to kill dingoes and spread negative images of the dingoes, which continues the cycle of viewing these animals in a negative light.

Crocodiles – Haley Beeson

Crocodiles are known around the world for their dangerous qualities and number of human attacks. However, this species was brought into further detail by a ranger at Billabong Sanctuary. Crocodiles, alligators, gharials, and caimans are reptiles that belong to the group known as crocodilians. This group is classified by their large, long, lizard-shaped bodies, and two pairs of short legs. Crocodiles are a unique species apart from the alligator, with a broader snout and teeth aligned with an overbite. Specifically, the Saltwater Crocodile or the Crocodylus Porosus is the world’s largest living reptile with males reaching lengths of up to 19 feet and over 2000 pounds and females reaching lengths up to 9 feet and over 300 pounds. Their habitat includes the coastal islands, coastlines, estuaries, rivers, creeks, and wetlands. Regardless of their name, these crocodiles can live in both saltwater and freshwater along with hypersaline waters. Their location is not determined by the quality, type, or turbidity levels of water but rather the geographic position and what types of food are present. For example, mountain ranges serving as a geographic barrier may limit this species’ presence throughout Queensland, Australia.

Their bodies are adapted to an aquatic environment. Bony plates known as osteoderms cover the skin, transferring heat to the rest of the body via tiny blood vessels. This allows the crocodile to remain mostly underwater during hunting while still receiving the heat from sunlight it needs to survive. Juvenile crocs rarely expose their backs for safety reasons. Therefore, they leave majority of body under water while exposing these osteoderms to capture heat. Also, the eyes, nostrils, and ears close under water for protection by a small layer of skin covering. With the ears closed under water, dots along jawline serve as a sensory organ that picks up on vibrations throughout the water. They are able to remain partially submerged or completely underwater due to the fact that they can hold their breath for up to an hour refusing their heart rate to 2-3 beats per minute. The crocodile can bite under water as well without the worry of water entering stomach and lungs.

This species has one of strongest bite forces of any animal alive today with a force of up to 3700 pounds per square inch, enabling them to have somewhat dull teeth and still remain effective predators. Crocodiles eat a variety of fish, birds and other animals. A major hunting limitation is that their legs prove to be useless for everything besides getting them out of the water as well as their heavy tail only enabling them to stand upright in the water but overall serving as an anchor. Since 2000, there have been 22 human fatalities in Australia by the cause of crocodiles, with two during 2017. Crocodile farms beginning in the twentieth century, along with various other unsustainable hunting practices left less than 3000 saltwater crocodiles left in Australia’s Northern Territory. Since 1970, this species has been protected and are gradually coming back to their previous numbers. Estuarine Crocodile Management oversees industry and development to ensure proper compliance with guidelines.

3 year old crocodile

 

Management – Sophie Purut

After learning about dingoes and crocodiles, the UNC students were posed a question by Jules, the ranger at Billabong Sanctuary- “What are the differences in how crocodiles and dingoes are managed, and why?” What seems like a simple question reveals the deeper beliefs and complexities in human attitude toward these two different creatures. One animal is managed with relocation to various animal establishments, with the other being actively hunted and trapped, showing that economic incentives and emotional opinions play a huge part in animal management.

 

So what are the intricacies of these two management styles? In regards to crocodiles, it includes a process of zoning, educating the public, and relocating crocodiles to zoos or farms to be used for breeding or educational awareness. With the zoning process, each area has different criteria and leniences in regards to a crocodile presence. For example, in an area marked Zone A (where there should be little interaction between crocodiles and humans), any and all crocodiles are removed. An area marked Zone D, however, is a location where crocodiles are known to be transitory, so monitoring for crocs over 2 meters and signage is considered all that is necessary. All crocodiles that are caught are humanely transported to live out the rest of their natural life in breeding programs or at zoos, a stark contrast to the treatment of dingoes.

 

While crocodiles seem more menacing and dangerous than dingoes, they do not pose the same economic losses to livestock as the small, more dog-like dingo. Seen as a major threat to sheep, dingoes are actively hunted, baited, trapped, and poisoned. The dingo’s listing as “vulnerable” on the IUCN red list but a declared pest in some areas creates murky legislation that hardly protects the animal at all. Some landowners do choose deterrence practices, such as fences and guardian animals for livestock herds, but these come with their own share of consequences. Fences high enough to keep out a dingo keep out a plethora of other migrating animals as well. Sanctuaries like Billabong are trying to change the public perception of these small predators by letting people take photos with and pet their resident dingoes, but the whole of Australia still has a long way to go in their attitude towards the animal.

The Wet Tropics: A Haven for Biodiversity

A Haven for Biodiversity by Peggy Mullin

It is no secret that Australia is a uniquely beautiful place. From the peaks of its tallest mountains to the depths of the reefs dotting its coasts, the continent offers some of the most diverse flora and fauna on Earth. This endlessly beautiful and diverse region was developed over millions of years, through the gradual and sometimes abrupt shifting of continental plates, a process known as continental drift. In a short lecture period, ranger Ross McLennan took us through the interesting geographic history of this area, and the ways in which this process shaped the region throughout the past.

300 million years ago, the world’s continental plates were conjoined in one huge land mass known as Pangaea. Through geological processes, these plates gradually drifted apart over the next several million years, with the most significant split occurring about 80-50 million years ago. This event resulted in the creation of a new land mass known as Gondwana, which was marked by continental boundaries relatively similar to those present today.

However, Gondwana was markedly different in that the continents we know today as South America, Antarctica and Australia remained connected. Fossil records support this historical progression; the oldest known Platypus and Eucalypt fossils were found in South America, a region which is today devoid of any extant Platypi or Eucalypt species.

 

This graphic shows the historical progression of continental drift. The key connection between South America, Antarctica and Australia is visible towards the end of the progression.

The existence of Gondwana 50 million years ago is an interesting stage in the Earth’s continental development, because at this time South America, Antarctica and Australia were all relatively temperate regions. As the Earth began to develop cold regions toward the poles, the continents also drifted into the positions they currently occupy. For Australia, this meant moving toward the equator at a rapid 3 centimeters per year, a movement which continues even today.

This movement allowed the continent to maintain a relatively constant, temperate climate for a much longer period of time than any of the other former constituents of Gondwana. This means that flora and fauna were allowed to develop and speciate in relative isolation, leading to incredible amounts of biodiversity on the continent of Australia.

Though the continent has gradually ‘dried out’ as it has moved North toward the equator, one region remains an in situ reflection of the former state of the continent: the Wet Tropics region of eastern Australia. Most winds in Australia carry wet and warm air from the southeast. These currents bump up against the mountains of the continent, causing these currents to deposit their moisture via rainfall on the eastern side of the mountains. Thus, the continent’s ancient rainforests are continually maintained on the eastern edge of the continent, particularly in the Wet Tropics region.

Recognition as a World Heritage Area by Taylor Woollen

Ross moved on from the topic of Pangea and Gondwana onto the topic of the significance of the wet tropics area, which was created by the Australian plate’s movement across Earth’s surface millions of years ago. This wet tropics area was designated as a World Heritage Area in 1998 and is now called The Wet Tropics World Heritage Area (WTWHA). This area of Australia became a World Heritage Area by meeting four criteria created by UNESCO. The first is that the area must have natural beauty. The second is that examples of earth’s history must be evident, including record of life. The third is that there must be ongoing ecological and biological processes. The fourth is that there must be significant natural habitats for the conservation of biological diversity and threatened species. Focus is placed on endemic and endangered species for the fourth criterion.

Reason number one, natural beauty, can be easily met if an area looks appealing. Australia’s wet tropics easily meet this criterion because the wet tropics have beautiful views of the mountains and the coast, there are beautiful trees and other plants, waterfalls, many animals, and more.

Evidence for reason number two, examples of earth history, can be found in the evolution of ferns, conifers and cycads, flowering plants, animals, marsupials and eucalyptus forests, and songbirds. The wet tropics have the highest level of fern diversity in Australia, 31 out of 36 families of ferns are found here, and evidence of primitive ferns families is found in the wet tropics as well. A great diversity of cone bearing cycads and southern conifers can be found in this area, and cycads are associated with the most primitive pollinator system of the area. 16 out of 28 primitive plant families are found in the region. These early flowering plants were pollinated by insects that spread pollen by walking across plants. The discovery of these primitive flowering plants kicked off the protection of this area in Australia because this area represents the world’s primitive flowering plants. Evidence of adaptation and evolution of plants and animals as the Australian continent dried has been found, and ancestral lineages of song birds have been recorded. Researchers discovered that birds originated in the Southern Hemisphere and eventually spread into the Northern Hemisphere, which contradicted the previous belief that birds spread from the north to the south.

The third criterion, evidence of ongoing ecological and biological processes, is evident in processes leading to speciation, processes leading to the evolution of life on mountains, landscape processes, interactions between open forests and rainforests, recolonization after the recent glaciation, recolonization on recent volcanic activity, and lastly, natural recovery processes after cyclones. An example of recolonization on recent volcanic activity is a lake that filled in a crater created by volcanic activity.

Lastly, the fourth criterion is conservation of habitat for biodiversity and rare and threatened species of flora and fauna. Australia’s wet tropics contains many endemic species: 29 reptiles, 27 frogs, 12 song birds, 12 mammals, and 678 plants. The wet tropics also account for only 0.26% of the Australian continent, but within this area, many Australian species are found: 65% of ferns, 21% of cynads, 37% of conifers, 30% of orchids, 36% of mammals 30% of marsupials, 58% of bats, 50% of songbirds, 25% of frogs, 23% of reptiles, 60% of butterflies, and 41% of freshwater fish. The amount of endemic and unique species in this area indicate that protecting this area is critical because nowhere on Earth is similar to this unique ecosystem.

We went on two hikes today within the WTWHA, and walking through this unique landscape, we were able to understand the importance of this area and how this area meets UNESCO’s four criteria. We saw many unique plants species, a few bird species, and incredible sights such as waterfalls and a rock garden (an area made up of huge boulders).

The Value of the Region by Caleigh Sewell

It is easy to understand why Australia’s Wet Tropics region has been considered a globally significant area, but why are people drawn to these remote and isolated lands and why are some people against its protection?

The Wet Tropics of Northeastern Australia became recognized as a World Heritage Area in 1988 and is one of the most popular tourist sites in Australia. According to Ross McLennan, there are a number of reasons why people are drawn to the Wet Tropics, but the largest incentives are the undeveloped scenery, the unique and native species, and the indigenous culture. While we didn’t cover the culture of the indigenous people during today’s hike through the Wet Tropics Rainforest, we certainly saw plenty of beautiful, undeveloped scenery and many native species. The area we hiked through was right next to Lake Paluma and contained hardly any infrastructure except for a few campsite spots and compost toilets. As we began our hike, we quickly escaped any trace of man-made facilities and found ourselves immersed in a vast, undeveloped land. The deeper into the hike we got, the more it felt like we were miles away from any man-made infrastructure. Every scenic overlook showed pure, untouched nature (Figure 1), something that can be hard to come by, even in the natural world.

Figure 1. Scenic overlook on our rainforest walk through the Paluma National Park.

Along the hike, our guide, Ross McLennan, pointed out many examples of native species to the Wet Tropics whose presences are vital to maintaining the ecosystem. Some species we could physically see, such as the fig tree (Figure 2) which wraps its vines around a host tree and strangles it, eventually causing the tree to die, fall over, and create an open area through which sunlight can penetrate and allow dormant Oscar trees to grow to their full capacity. The species we didn’t see Ross showed evidence of or simply talked about, such as the Cassowary bird who eats a certain type of berry and later defecates, creating the perfect incubation for the seeds of the berry to germinate. It’s this kind of untouched nature and unique ecosystem niches that act as incentives for visitors to come and visit the Wet Tropics of Australia and learn why it is so important to protect it.

Figure 2. The ecological effects of a fig tree “vine” being explained by tour guide Ross McLennan.

While there are plenty of incentives for tourists to come visit the Wet Tropics, there are also disincentives, which can be just as important when determining how to make a place as appealing to visit as possible. The main disincentive is overdevelopment, which makes since because it is opposite of the undeveloped scenery incentive. It is always disappointing to visit an advertised natural landscape and see a bunch of hotels and restaurants right next door. People are typically trying to get away from all that if they are visiting a natural location. Another disincentive is pollution. Not only is it unappealing to the eye, but a lot of people care about the natural environment and know that pollution is harming the environment they are trying to protect and continue to enjoy for generations to come. Luckily the Wet Tropics rangers are very good about maintaining a clean and untouched vibe for their wilderness area, and so tourists continue to come visit this region and support its protection.

Unfortunately, there are some people who are not in favor of the protection of the Wet Tropics. Strangely enough, most of these people live locally or relatively near these areas. The main reason they are not in favor of the protection of the Wet Tropics is because with the protection comes lots of restrictions and regulations. Residents and visitors are no longer allowed to use motorboats, go motor biking, or do a number of other activities in these protected areas. While not everyone is going to be 100% on board with protecting a World Heritage Area, but if we focus on how to make the visit to the Wet Tropics as appealing as possible, we can hope that the support for protecting it will continue to grow.

 

Learning about the Wet Tropics with Ranger Ross

Ross moved on from the topic of Pangea and Gondwana onto the topic of the significance of the wet tropics area created by Australia’s movement on Earth’s surface. This area was designated as a World Heritage Area in 1998 and is now called The Wet Tropics World Heritage Area (WTWHA). This area of Australia became a World Heritage Area by meeting four criteria created by UNESCO. The first is that the area must have natural beauty. The second is that examples of earth’s history must be evident, including of record of life. The third is that there must be ongoing ecological and biological processes. The fourth is that there must be significant natural habitats for the conservation of biological diversity and threatened species. Focus is placed on endemic and endangered species.

Reason number one, natural beauty, can be easily met if an area looks nice. Australia’s wet tropics easily meets this criterion because the wet tropics have beautiful views of the mountains and the coast, there are beautiful trees and other plants, waterfalls, beautiful animals, and more.

Evidence for reason number two, examples of earth history, can be found in the evolution of ferns, conifers and cycads, flowering plants, animals, marsupials and eucalyptus forests, and songbirds. The wet tropics have the highest level of fern diversity in Australia, 31 out of 36 families of ferns are found here, and evidence of primitive ferns families is found in the wet tropics as well. A great diversity of cone bearing cycads and southern conifers can be found in this area, and cycads are associated with the most primitive pollinator system of the area. 16 out of 28 primitive plant families are found in the region. These early flowering plants were pollinated by insects that spread pollen by walking across different plants. The discovery of these primitive flowering plants kicked off the protection of this area in Australia because this area represents the world’s primitive flowering plants. Evidence relating to animals include the adaptation and evolution of plants and animals as the Australian continent dried as well as the ancestral lineages of song birds. Researchers discovered that birds originated in the Southern Hemisphere and eventually spread into the Northern Hemisphere, which contradicted the previous belief that birds spread from north to south.

The third criterion, evidence of ongoing ecological and biological processes, is evident in processes leading to speciation, processes leading to the evolution of life on mountains, landscape processes, interactions between open forests and rainforests, recolonization after the recent glaciation, recolonization on recent volcanic activity, and lastly natural recovery processes after cyclones. An example of recolonization on recent volcanic activity is a lake that filled in a crater created by volcanic activity.

Lastly, the fourth criterion, conservation of habitat for biodiversity and rare and threatened species of flora and fauna. Australia’s wet tropics contains many endemic species: 29 reptiles, 27 frogs, 12 song birds, 12 mammals, and 678 plants. The wet tropics also account for only 0.26% of the Australian continent, but within this area, many Australian species are found: 65% of ferns, 21% of cynads, 37% of conifers, 30% of orchids, 36% of mammals 30% of marsupials, 58% of bats, 50% of songbirds, 25% of frogs, 23% of reptiles, 60% of butterflies, and 41% of freshwater fish. The amount of endemic and unique species in this area indicate that protecting this area is critical because nowhere on Earth is similar to this unique ecosystem.

We went on two hikes today within the WTWHA, and walking through this unique landscape, we were able to understand the importance of this area and how this area meets UNESCO’s four criteria. We saw many unique plants species, a few birds species, and incredible sights such as waterfalls and a rock garden (an area made up of huge boulders).

A Walk to Remember: Learning About the Wet Tropics Rainforest

Filled with anticipation, the UNC students filed out of the City Oasis Inn and into the nondescript van waiting outside. After a brief introduction, our Hidden Valley guide, Ross McLennan, loaded our bags, and soon we were chugging down the road to our next destination.

Exiting the city limits of Townsville introduced us to an entirely new landscape- sugar cane fronds waved in the breeze, and mountains began to loom closer. We were leaving the beaches behind for the rainforest of the Paluma Range National Park. Straight roads soon turned into curving lanes that brought us winding up through the forest, the colors changing from tans and browns to lush shades of green. Ross’ commentary broke up the pockets of awed silence as students’ eyes were locked to the changing scenery outside.

Little Crystal Creek was our first stop, an oasis of waterfalls and swimming holes free of crocodiles. After a brief lunch, tentative toes were dipped in the water until, either by free will or slipping, almost everyone was in the freezing pool. The shivering soon disappeared, however, leaving us to splash and relax in the water until it was time to leave.

One of the waterfalls at Little Crystal Creek

The bus ride gave us time to warm up until Ross had us outside once again, this time to experience the true wet tropics of North Queensland. Our brief walk through the forest was filled with not only a diverse array of flora and fauna, but also a bounty of information from Ross.

We learned about the vertical structure of the rainforest, where a thick upper canopy dominates with a few saplings below. This dense canopy creates an extremely shaded environment that limits the ground structure to a few straggly plants, starved of sunlight. The small trees, or oscars, grow until they reach the middle layer of the rainforest. When an older, larger tree falls and an opening in the canopy is created, oscars race to fill the gap, competing for space, sunlight, and resources. Sunlight is the source of life for all the plants of the rainforest, and individual organisms must act quickly to survive.

Oscars seen in the rainforest

Closer to the ground level, Ross explained the function of the leaves of the rainforest. These waxy leaves have the ability to cloud-strip, or collect moisture from the atmosphere when it is not precipitating. The wide shape of the leaves with an elongated tip at the point allows for the collection of dew, and then the slow drip of water near the base of the plant. This “rainfall” supplies water to the roots of the rainforest, easing the need for competition for water falling through the thick canopy. Cloud-stripping also provides water to the sugar cane farmers at the base of the mountains. In fact, 40% of the water used by sugar cane farmers comes from this cloud-stripping function in the Paluma Range National Park. The farmers often endorse the protection of this rainforest, as their livelihood is dependent on the flora above.

Continuing our walk through the rainforest, we began to question what the various vines and plants were snaking around the trees. We learned that these were parasitic plants, utilizing the height of the trees to climb to the sunlight above. The strangler fig wraps itself around a doomed tree, growing toward the sunlight while strangling its host. Another parasitic vine, the wait-a-while, has spiky barbs that hook onto plant life to climb higher. While trees are eventually killed by the parasites, Ross explained that it is possible for the vines to stay in their form and survive after their host’s death.

The strangler fig

Soon we arrived at a behemoth of a tree, with buttress roots extending to five feet above the ground. Ross explained that it was a quandong tree, and the tall, flat roots were used for shields by the indigenous clans hundreds of years ago. The roots are a necessary component of the tree, acting as support for the towering trunk and branches above and holding in compost to prevent other trees from growing around its base. It also serves as a habitat for a variety of species, from lichen and mosses to small mammals and insects. The group paused happily for several minutes to observe a small mouse scampering up the tree, peeking out from behind the roots at the students below.

The blue quandong tree with buttress roots

On our walk back to the van, there was a quiet focus on the environment around us, as everyone took in the magnitude of the rainforest. Small animals were heard rustling in the brush, bird song and insect buzzing filling the air. The rainforest became something more to us, not simply a picture in a science book, but a real living system that we must protect and appreciate.

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