The world’s tropical rainforests are located along the Inter
Tropical Convergence Zone (ITCZ) where the low pressure forces hot moist air
upwards and falls down when it cools. It is oftentimes referred to as the
“rain making machine.” This ITCZ moves around seasonally, hence its unstable
nature, shifting from the Tropic of Cancer in the summertime to the Equator in
the fall and finally to the Tropic of Capricorn for the winter months. Due
to this heavy orographic precipitation, there are specific plant adaptations
that are unique to this biome. There are high closed canopies with
shallow root systems. None of the sunlight is able to reach the forest
floor, so the soil is very poor. Additionally, 95% of the biomass is
locked up in the plant itself. It is home to many epiphytes, or plants
that live on other plants, and lianas vines, which is essential in the
transportation of water up to the top of the canopy. The tropical
rainforests of the world are the most diverse places on the planet.
Source: Rainforest Animals at Animal Corner
Source: World Wildlife Fund
Australia’s
Tropical Rainforest
Australia is home to many different biomes, including several
rainforests from the temperate, dry, tropical and sub-tropical. The
tropical rainforests are located in North Queensland, which is part of the
Daintree National Park. Queensland is located in the northeast section of
Australia and its tropical rainforests are found in the coastal, narrow and
heavily rain prone belt in the northeast region. The largest area of pure
tropical rainforest lies between Cooktown and Townsville in the tropics of
Queensland, called Cairns, which extends nearly 2900 square miles. The
second largest rainforest is named Mackay and the smallest engulfs the
Warginburra Peninsula and includes the Normanby Range (Hogan 2008). Much of
Queensland is mountainous, with coastal lowlands that link the higher mountains
and hills through steep slopes. Annual rainfall ranges from 47 to 315
inches per year with 75-90% occurring between November and April (Goosem 2000).
The
History
Historically, tropical rainforests have dated back around 415
million years ago, beginning their formation on the supercontinent of Gondwana.
Gondwana was the southern of the two landmasses that made up Pangaea.
As the slow natural division of the landmasses occurred, Australia, New
Guinea, and New Zealand were all connected at one point in what was called
Australasia. Other major regions where tropical rainforests live are in
America, Africa, Southeast Asia, and Madagascar (Corlett et al. 2006). This
Australasia continent was isolated from the rest of the earth, thus numerous
endemic plants and animals lived and continued to thrive in these areas.
Specifically, the rainforests in Australia are directly located in the
wet winds path blowing from the Pacific Ocean, so the soils and undergrowth are
dense and rich (“Rainforest Animals”). The Daintree Rainforest located in North
Queensland is listed by the World Heritage-list as not only the oldest tropical
rainforest on the planet but also the largest area of rainforest, stretching a
little over 460 square miles (“The Daintree Rainforest Australia”). The Queensland region of
tropical rainforests has been stable for approximately 180 million years before
present, further emphasizing the fact that it is the most primitive forest on
the planet (Hogan 2008).
Historical
State
In the past, the climate in the tropical rainforests in northern
Australia used to be less than what it is now. Contributing to the increase in
the climate change throughout the years has been the greenhouse effect and as a
result has impacted the ecosystem and the species living in them (Hughes 2003).
According to the Intergovernmental Panel on Climate Change, “most of the
observed warming over the past 50 years is likely to have been due to the
increase in greenhouse gas concentration” (IPCC 2001a). The temperature in
Australia’s tropical rainforests have increased 0.1–0.2°C per decade since
1951, as well as the amount of rainfall the ecosystem receives yearly (Hughes 2003).
It is projected that by 2030 the annual average temperatures will increase from
0.4-2.0°C and by 2070, the “annual average temperatures my increase by
1.0-6.0°C” (Hughes 2003). It is most devastating that the tropical rainforests in
Australia are the ones that are going to be greatly affected by the climate
change that will be occurring in the next 50-100 years. As a result of this
impending climate change, many of the region’s endemic vertebrates inhabiting
these areas will most likely decrease due to the fact that their homes will
also “decrease by 50% with only a 1°C warming” (Hughes 2003). Also impacted by the
altering of the climate change and rainfall in the future are the plant species
present. The change in climate and rainfall may cause an extinction in some
plant species that are accustomed to certain climates, like the eucalypt
species that “have current ranges spanning less than 3°C of mean annual
temperature, with 41% having a range less than 2°C and 25% with less than 1°C”
(Hughes et al. 1996). It is evident that with the escalating climate change and
annual rainfall that certain species in the tropical rainforests in Australia
will soon disappear if they can’t adapt to the new conditions.
Source: Krockenberger, A. K, Kitching, R. L. and
Turton, S. M 2003, Environmental Crisis: Climate Change and Terrestrial
Biodiversity in Queensland, CooperativeResearch Centre for Tropical
RainforestEcology and Management. RainforestCRC, Cairns, viewed N/A,
http://www.rainforest-crc.jcu.edu.au/publications/research
reports/ReportPDFs/environmentalCrisisResearchReport.pdf.
Human
Impacts
Tropical
rainforests are one of the most beautiful places in the world, with its rich
diversity of both animal and plant species. However, these places are being
slowly destroyed in the span of hundreds of years up until now due to numerous
human impacts such as “subsistence activities, oil extraction, logging, mining,
fires, war, commercial agriculture, cattle ranching, hydroelectric projects,
pollution, hunting and poaching, the collection of fuel wood and building
material, and road construction” (Butler 2012). Throughout the course of time these
destructive activities have resulted in the loss of animal species and has
diminished the land area in the ecosystem.
In the past,
the human impacts that have contributed the most to harming the tropical
rainforest in northern Australia were indigenous people who used the
ecosystem’s resources to sustain their lives and also logging. Currently,
recreational activities and the increase in tourism in Australia’s tropical
rainforests in the last couple of years have now contributed to the damage in
certain parts of the ecosystem. It is no surprise that the biodiversity of the
plants and animals in the Australian rainforest are the main incentives to
visit this area (Turton 2005). The impact of each recreational activities such as
“sightseeing, hiking and walking, horse riding, camping, kayaking, swimming,
picnicking and use of off-road vehicles” vary in the damage that they cause
(Hammitt and Cole). Largely, these impacts result in the destruction of
vegetation from hiking; soil conditions changing which produces soil erosions;
the expansion of soil pathogens due to mountain bikes and hiking boots that
carry the pathogens on the sole of their shoes; swimming and other water
related activities alters the quality of the water (Turton 2005). In order to keep
these tropical rainforests people need to be more conscious of how their
actions may negatively be affecting the lives of the animals and plants living
within this ecosystem. There are ways to prevent harmful impacts or at least minimize
the negative effects people have on tropical rainforests, and all they need to
do is educate themselves on sustainable uses regarding recreational activities.
source:
FAO/mongabay.com
Future
Prospects and Improvements
Based off of the current
human impacts, there will be serious detriments to the tropical rainforest in
Australia if nothing changes as it is currently in a vulnerable state. For example, the threat of global warming
could be detrimental in the future because of its affect on the climate change. Many of the plants and animals may not have
time to adapt to the rising weather temperatures. Additionally, because of the concentration of
the Australian vertebrates in the upland hills, they are especially prone and
vulnerable to changes in climate (Corlett 2006).
The region is also very vulnerable to pest species and according to a
Scientist, Warren, there are over 500 naturalized plant species in the area
that had previously not existed in the tropical rainforests of Australia. He also identified “7 mammal, 5 bird, 5
freshwater fish, 2 reptile, and 1 amphibian species to have become naturalized”
(Goosem 2000). Furthermore, since there is
already a network of large power lines and over 1,200 km of maintained roads
extending through the rainforests, we can only imagine what the future
rainforest will look like. The
rainforests in Australia will most definitely become more vulnerable in the
future if nothing is done to stop the destruction of this beautiful land.
As aforementioned, the
human impacts have had and will continue to have a detrimental impact on the
tropical rainforests, but there is hope!
In order to improve the human impacts on this ecosystem, there are
several things we as humans can do. The
Australian Rainforest Conservation Society has helped to protect the
rainforests so far and their continuation and dedication to this cause is
invaluable. For example, this society
has stopped logging in North Queensland and has successfully campaigned against
the rainforest logging in Central Queensland (“Australian Rainforest Conservation Society”). The World Wildlife Fund also works with the
government to improve the conservation of species such as turtles and
shorebirds in order to stop their decline on a national scale. Other effective approaches to managing and
sustaining the life in Australia is to close the eroded tracks and trails from
human use to allow for the regrowth of the vegetation that once lived,
maintaining the canopy cover, and in the wet season, closing the roads that are
susceptible to erosion and die-back (Turton 2005). With these approaches and human awareness of
the problems facing the rainforests, we hope that people become educated and
take everything into consideration when visiting these threatened
habitats.
Works Cited
"Australian
Rainforest Conservation Society - Objectives and Achievements." Australian Rainforest
Conservation Society - Objectives and Achievements. N.p., n.d. Web. 28 Nov.
2012. <http://www.rainforest.org.au/arcsinfo.htm>.
Butler, Rhett.
"Threats to the Rainforest from Humankind." Mongabay.com.
N.p., 27 July 2012. Web. 28 Nov. 2012.
<http://rainforests.mongabay.com/0803.htm>.
Corlett, R., and R. Primack.
"Tropical Rainforests and the Need for Cross-continental Comparisons."
Trends in Ecology & Evolution 21.2 (2006): 104-10. Print.
"The Daintree
Rainforest Australia." Daintree Rainforest Australia Information.
World Land Trust (WLT), n.d. Web. 26 Nov. 2012.
<http://www.therainforests.info/landscape/daintree.htm>.
Goosem, Steven.
"Northeastern Australia." Wildlife Conservation, Endangered
Species Conservation. N.p., 2000. Web. 26 Nov. 2012. <http://worldwildlife.org/ecoregions/aa0117>.
Hogan, C. Michael.
"Queensland Tropical Rainforests." Queensland Tropical Rainforests.
N.p., 22 Sept. 2008. Web. 26 Nov. 2012. <http://www.eoearth.org/article/Queensland_tropical_rain_forests?topic=49597>.
Hughes, Lesley.
"Climate change and Australia: trends, projections and impacts."
Austral Ecology 28.4 (2003): 423-443.
Laurance, William F.
"Rainforest fragmentation and the structure of small mammal communities in
tropical Queensland." Biological Conservation 69.1 (1994): 23-32.
"Rainforest Animals
at Animal Corner." Rainforest Animals at Animal Corner. N.p., n.d.
Web. 26 Nov. 2012. <http://www.animalcorner.co.uk/rainforests/rainforests.html>.
Turton, Stephen M.
"Managing environmental impacts of recreation and tourism in rainforests
of the wet tropics of Queensland World Heritage Area." Geographical
Research 43.2 (2005): 140-151.
