Plants have adaptations to help them survive live and grow in different habitats. They have adaptations or special features that allow a plant to survive in a particular altitude, moisture requirements, aspect, temperature, soil, pH or salinity. These adaptations might make it very difficult for the plant to survive in a different place. This explains why one plant is found in one area, but not in another.
The section on Conservation Concerns just touches the tip of the ice berg and could be argued for hours. I am not an expert and have never professed to be but even to me the writing is on the wall. Do something or perish.
The most horrific chart to look at is the following one from the Commonwealth Bureau of Meteorology. If this doesn’t send alarm bells ringing then what will? There is a real increase of 0.7 degrees to 1999 of which most of it has eventuated over the past 25 years and the rise has been sharper since 1999. If this is expediential as climatologists say then we have sown the seeds of an enormous problem that needs immediate action not words. It is expected that Australia’s climate will be affected more than most regions on the planet. Our wildlife will experience more extremes in temperatures and more extremes in precipitation while annual averages will increase by as much as 2 to 3 degrees over this century.
Australia is more vulnerable to the effects of global warming projected for the next 50 to 100 years than all the other habitable continents. Because of its extensive arid and semi-arid areas, high annual rainfall variability, existing pressures on water supply and the fact that it is surrounded by oceans. The continent’s high fire risk increases dramatically as natural areas are susceptible to even seasonal changes in higher temperatures and decreases in rainfall so to have any small change would place additional pressures on these already fragile eco systems. Add to this Australia’s population is highly concentrated in coastal areas, and its important tourism industry depends on the health of the Great Barrier Reef and other fragile coastal ecosystems. Impacts of climate change are complex and to some degree uncertainty reigns on the exact dimensions of the pending disasters. Increased foresight should forewarn all Australians of the potential calamity that will arise so that we can take some safe guards but what about the environment? Plans need to be put in place to mitigate the damage and adapt the best we can. Mitigation may reduce the ultimate extent of climate change and its impacts, but it requires global solutions and cooperation, while adaptation can be performed at national and local levels.
Melting of glaciers and ice sheets also contributes to sea level rise. Immense quantities of ice are held in the ice sheets of West Antarctica and Greenland, jointly containing the equivalent of approximately 12 meters of sea level rise. Deterioration or breakdown of these ice sheets would lead to irreversible sea level rise and coastal inundation across the globe. High and low tides will become greater with sea levels expected to increase anywhere from 1.5 meters to 6 meters. A 1 meter increase will see 700,000 Australian families displaced with over a million of our immediate Neighbouring Island residence needing to be taken in as refugees. This alone will place more pressure on land for subdivision, forests for housing, fisheries along the coast, acid soils, coastal erosion, disease and famine coupled with political antagonism of blame and counter blame. The stakes are high the reality of the situation has never been more drastic.
I am totally bewildered as to why governments worldwide have stood back and done nothing considering the effects of global warming were known as far back as 1970 with those predictions now are being confirmed and present predictions looking ominously deadly accurate to say the least. The first publications on affects of deforestation and temperature increases was done by Alfred Wallace back in the mid 1890’s.
Maps from http://www.bom.gov.au/
The desert is very dry and often hot. Annual rainfall averages less than 300mm per year, and that rain often comes all at the same time. The rest of the year is very dry. The sunlight is direct and stronger than on the coast due to the dry atmosphere. The soil is often sandy or rocky and is unable to retain much water. The winds are often strong and dry while the plants are exposed to extreme temperatures and drought conditions so plants have adopted several mechanisms for the efficient use of water and to prevent excess water loss. The slower growing or seasonal growing during the wet season takes advantage of the short wet season and requires less energy. Arid zones typically have rapid water evaporation from the ground following precipitation accentuating the spurts in growth. Some methods adopted by plants to survive include:
* Long, deep penetrating roots help secure water that has seeped deep into the desert soils.
* Succulent stems and leaves store water for use during dry periods.
* The leaves are absent or small seasonal leaves develop during the wet season. The lack of leaves helps reduce water loss during photosynthesis. Leafless plants often conduct photosynthesis in stems which are green and thickened.
* Many plants are annuals have a short life cycle, germinating in response to rain, growing their vegetive parts and sexual parts and dying all within one season this way they circumvent droughts.
* Plants with hairy leaves reduce water loss by shading and creating humid microclimates away from breezes.
* Many Australian plants have leaves that hang vertically down and turn throughout the day to expose a minimum surface area to the heat and glare.
* Spines along the stems, mid veins and on the leaves help to discourage animals from eating plants for their valuable water.
* Waxy coated leaves and stems help reduce water loss.
* Many plants have flowers that are nocturnal to lure pollinators who are more likely to be active during the cooler evenings.
* There is a concentration of plants along seepages and dry creek beds
The arid conditions in central Australia mean that soils take a lot longer to recover once they are disturbed. The lack of water makes desert environments vulnerable to any sudden changes and global warming historically is a sudden change. Climate change is increasing the extremes in weather which are threatening viable communities and environments on the edges. This is leading to desertification and is being exacerbated by human exploitation of ecosystems which is causing further land degradation, soil erosion, sterility and a loss of biodiversity. The increase in fire frequency and intensity is a major concern as will be the further reduction in rainfall.
The Tropical Rainforest
Tropical rainforests are warm to hot and humid where a lot of rain falls. In Australia the rainforests are restricted to a small area on the Great Dividing Range, Tasmania’s wilderness areas and far north western, Western Australia and the Northern Territory. The abundance of rainfall increases the risk of flooding, soil erosion, and rapid leaching of nutrients from the soil. Leaching occurs when the minerals and organic nutrients of the soil are removed from the soil, usually by water. This leaching is exasperated by human activities such as clearing. Plants grow rapidly and quickly use up any organic material left from decomposing plants and animals. This results in soils that can be nutrient poor if the forest canopy is removed. The tropical rainforest canopy provides dense shade and a humid moist microclimate beneath. The plant diversity is greatest in these forests because of the even warmth and moisture. Some methods adopted by plants to survive include:
* The leaves have developed drip tips, accuminate or acute leaves that bend downwards at the tips.
* The leaves are often covered in wax so that excess water runs off quickly, to discourage bacteria and fungi growing.
* Buttresses, flanged, prop and stilt roots help hold up plants in the shallow soils and to collect leaf litter.
* The prevalence of climbing plants reaches their climax in rainforests.
* The flowers are usually small and often rely on small animals and birds for cross pollination.
* Smooth barks assist the run off of water while the plants have shallow roots to help capture nutrients from the top soil.
* Many epiphytic plants grow high in the trees have adapted spongy roots and tissues to absorb water while some have a central reservoir from which they absorb the water channeled down from their leaves or have leaf hairs that can absorb the water and trap falling leaves and dust particles to mulch.
Biologists consider tropical rainforests some of the richest, most exciting areas on earth! Despite being vitally important centers of biodiversity, they cover only about 6% of the Earth’s land surface which is less than 50% of the area they covered 50 years ago.
Rainforests are perhaps the most endangered habitat on earth. Each year, some 140,000 sq km of rainforests are destroyed worldwide. Rainforests are being felled for short term profit without any consideration for future generations. The most endangered rainforests are those in West Africa, where human populations are doubling every 20 years, and in Central America and South-East Asia.
Although large areas of rainforest remain in Australia we cannot be complacent as we too have already destroyed over 75%, over 75% in New South Wales have vanished for ever over 75% in Queensland, the Northern Territory and Western Australia and now Tasmania wants to follow this trail of destruction. Time is short if we are to save the remaining rainforests for future generations.
The Temperate Rain Forest
There are the northern highland temperate rainforests and the southern seasonal temperate rainforests. The northern temperate rain forest features minimal seasonal fluctuation of temperature. The winters are mild and the summers cool. The temperate rain forest receives a lot less precipitation than tropical rainforests but often collects additional rainfall through orographic precipitation. This maintains cool even temperatures and low evaporation. The soils are not as poor as those in the tropical rainforests. Large evergreen trees, some reaching 100 meters are known being the tallest hardwoods in the world. Some methods adopted by the plants to survive include:
* Epiphytes such as mosses and ferns grow atop other plants to reach
* Cooler temperatures lead to slow decomposition but seedlings grow on the compost created on the surface to gain the nutrients from decomposing dead plants and leaf litter.
* The trees can grow very tall due to amount of precipitation and low evaporation rates.
* Many trees have thick bark to protect the inner live bark against cold winter temperatures.
* Most trees have thinner, broad leaves that can utilize the available winter sunlight better.
There are four distinct seasons in the southern temperate rainforests forests, spring, summer, autumn, and winter. The temperatures vary from hot dry summers with cold wet winters that may fall below freezing in the winter. The tallest trees make up the forest canopy which can be 100 meters or more tall. Beneath the canopy, the understory contains smaller trees and young trees. These understory trees are more shade tolerant than canopy trees. Below the understory is a shrub layer. The forest floor is often covered in mosses, and ferns. Fallen leaves, twigs, and dried plants cover the ground, decompose, and help add nutrients to the topsoil.
Temperate rainforests have depleted dramatically on the mainland of Australia over the past 100 years. Rainforests are being felled for short term profit without any consideration for future generations and climate change especially in Tasmania at the present time.
The alpine areas account for a small area in Australia mainly along the southern peaks of the Great Dividing Range and the south west and central Tasmania. Alpine areas are moist often with frosts extending into autumn and spring with occasional summer frosts and snow. The summers are short and cool with long, cold winters. The alpine areas are covered in snow during the winter. Drainage is usually poor due to the breaking down of rocks into fine clay particles. The precipitation rate is good, falling in the form of rain, sleet and snow coupled with very low evaporation rates due to the cold. Most areas are exposed and subject to cold southerly winds. The days during summer are long while the winter daylight is short in the southern regions. Plant life is dominated by low growing heaths, mosses, grasses, and sedges. Some methods adopted by plants to survive include:
* Alpine trees are sparse in their habitat, short usually less than 10 meters and bend away from the prevailing winds.
* Plants are deep green in color often with orange and reddish tinges which helps them absorb solar heat.
* Many plants are covered in thick bark to protect the inner live bark from the cold.
* Many plants are covered a dense layer of transparent hair which forms a warmer micro climate around their tissues.
* Many of the low growing plants form clumps and grow in the crevices of the rocks to protect themselves from the wind and cold.
* Many plants have open dish like flowers that are held a slightly above the plant in a position to focus the maximum available solar heat on the center of the flower.
Alpine regions are the most threatened wildlife zones in Australia due to global warming. 2 degrees warming will make a substantial difference to their environments which will cause erosion destabilizing the shallow rooted plants which make up the majority of species. Mosses, ferns and sedges are particularly vulnerable to soil disturbance and they are the backbone of such environments. Approximately 0.15% of the continent receives regular winter snow falls. The most extensive snow covered areas are in the southeast of the continent in the Snowy Mountains in NSW which accounts for around 2500 km2 and of this only 1200 km2 receives 60 or more days of snow cover and only 250 km2 which is just 0.0001% of Australia and can be classified as true alpine country. Costin et al. 2000.It is now very feasible to think that Australia’s alpine region will all be extinct by the year 2050; well on all models, all except for the highest 1 to 3 meters on Mount Kosciusko.
The article below is partially rewritten from http://www98.griffith.edu.au/dspace/bitstream/handle/10072/19118/49215_1.pdf;jsessionid=8098FF4BEA7D2D0257C67C3D312BEB98?sequence=1
* The loss of biodiversity from increasing fragmentation of habitat, disturbances to ecosystem processes is of vital concern already as this is already affecting bird migration. Hughes 2003; Pittock 2003; Parmesan & Yohe 2003; Root et al. 2003; IPCC 2007b).
* Global warming has already increased the risk of intense fires. Extreme fire events are predicted to increase in Australia as a result of climate change. Williams et al. 2001; Hughes 2003; Pittock 2003. In Australia the management of fires is a critical issue in national Parks and other wildlife protected areas. Fire directly affects ecosystems. Fire control in parks diverts resources away from other management activities. This includes resources used for fighting fires, and also for replacing burnt park infrastructure and rehabilitating fire trials. There will also be an increased potential for fire to spread from protected areas into urban areas in high risk periods, with resulting political and economic repercussions for protected area managers.
* The increase in feral animals and weeds is a major concern in alpine areas with the advent of Climate change. Weeds and feral animals already benefit from disturbance, with their spread in protected areas directly related to past and current human disturbance. Williams & West 2000.
* Increase in human demands on protected area ecosystem services: Change in demand for tourism activities: Current visitation to tourism destinations including protected areas is weather/climate dependent. Maddison 2001.
Grasslands, Mallees and the Arid Center
The mallees of Australia are our grasslands feature hot dry summers and cool wet winters. Rainfall is uncertain and drought is a periodic phenomenon. The mallees soil is extremely volatile and is depleting rapidly in the already low organic matter. The soils usually have a fertile upper layer due to the above ground portions of grasses dying off on an annual or perennial basis thus enriching the soil. The mallee areas are well suited to agriculture. About 67% of Australia’s mainland area is desert or arid lacking water to support larger populations. Some methods adopted by plants to survive include:
* Plants have developed in such a way that they are fire resistant surviving periodic burning which may be as regular as every 7 years to 20 years. Fires may destroy the above ground portions but the roots and culms of grasses below or near the surface survive to resprout. Trees and shrubs have lignotubers, epicorms or vast seed banks of stored just below the surface for such events.
* Roots of mallee trees, shrubs and grasses grow deep into the ground to absorb as much moisture as they can. Australian grasses are use to low grazing activities.
* The plants usually have thicker, narrower leaves to lessen water loss.
* Many grasses take advantage of exposed, windy conditions that are beneficial to wind pollinated plants.
* Flexible stems enable the plants to bend in the wind without breaking.
Australian mallee communities have been largely decimated from over grazing, farming of cereal crops and the deliberate and unintentional introduction of feral animals and weeds in the past. Surface salinity has increased dramatically as a result of poor irrigation practices. Thanks to better farm management and practices they were forging ahead of the critical positions years ago. In saying that very few virgin mallee communities survive today and there long term future is again bleak with the onslaught of terrorist number 1 Global warming. The increase in fire frequency and intensity is a major concern as will be the further reduction in rainfall.
These are the environments of fast flowing streams in the mountains to meandering rivers along the coast and farther inland. Some methods adopted by the plants to survive include:
* Plants that grow beneath the surface have leaves and stems display amazing flexible to cope with water currents.
* Many plants have air spaces in their stems to help support the plant in the water. This is particularly common in emergent species and plants with floating appendages.
* Submerged plants lack strong water xylem and phloem system, instead water, nutrients, and dissolved gases are absorbed or diffused through the leaves and stems directly from the water.
* The roots and root hairs are reduced or at times are absent.
* The main function of the roots is for anchoring the plant to the river bed or rocks and not for the absorption of nutrients and water.
* Plants that have leaves that float on top of the water expose the upper surfaces to the sunlight. The chlorophyll of floating plants is restricted to upper surface of leaves and have the upper surface covered in wax to repel water.
* The plants often produce seeds that float.
Fresh water communities have been largely decimated in Australia from over grazing, excessive pumping of water and the deliberate and unintentional introduction of feral animals and weeds in the past. Leaching of chemicals and salt from salinity waste farms has also increased the pressure on inland rivers and streams. With global warming and drier conditions native water plants and fish numbers and varieties are suffering probably irreversible damage. The coastal river systems are also facing annihilation if Global Warming models are correct and sea levels rise more than a few centimetres meter. A meter rise the worst case scenario will displace 700,000 Australian families but the toll on the environment will be catastrophic with thousands of square kilometres of prime fish mangrove breeding grounds being wiped out, water temperatures changing, salinity levels being adversely affected, acid sulphate soils releasing their toxic residues, chemical factories being submerged releasing toxic chemicals killing directly or causing algal blooms, (overseas nuclear plants also come into the equation) even waste dumps will be inundated diffusing long term poisons into the watery environments. This is a soup of massive proportions that we have created with no thought of the future and how to remedy the destructive conglomeration that will be foisted upon us all. Sinful when I consider I had little to do with it; and those who exploited every niche for self profit, but have to endure the pain and pollution of once pristine waterways that once surrounded my habitat.
Salt or Brackish water
The spectrum of marine ecosystem habitat types around Australia varies considerably from granitic and basalt outcrops to sandstone and limestone cliffs. Exposed and wild wind lashed cliffs, sandy, stony and rocky coasts through to quiescent waters in sheltered bays to
mangrove stands, salt marshes on the lower reaches of an estuary or intertidal zones with brackish water all go to make our extraordinary coastline. The coastal ecosystems vary as much as the landscapes all intriguingly beautiful in a picturesque way, rough, calm yet enticing.
While much was dealt with under Fresh water the coastal plains affected by tides are very much at risk of permanent extinction because of humans past greed.
Vast areas of coastal environments are threatened by sea level rise because extensive areas of wetlands, salt marsh and intertidal habitats lie at or just above the mean sea level. Australia has relatively broad flat coastal plains and coastal margins that lie just above the critical levels of 400mm and 1000mm that the sea levels are predicted to rise over the next 50 or so years so our beaches are very vulnerable to the kinds of massive disruptions from global warming impacts. Saline water will push up streams and into existing fresh water reservoirs creating havoc with bore shallow water and drinking water.
Plants are at the base of the food chain and here more than anywhere in Australia they are fraught with danger and extinction.
A heath or heathland is a shrubland habitat found mainly on free draining infertile, acidic, sandy soils that are characterized by open, low growing shrubby vegetation. Heaths are widespread throughout Australia with some special type of heathlands fast disappearing and considered endangered. They form extensive and highly diverse communities across Australia in humid tropical, sub humid sub tropical, to dry semi arid areas and coastal fringe areas. Some methods adopted by the plants to survive include:
* Plants grow close together in good rainfall areas and widespread interspersed with grasses in drier areas.
* Plants are usually compact and rounded less than 2 meters in height
* Australian heathlands are very diverse in plant species and are very rich in avian fauna, dominated by nectar feeding birds such as Honeyeaters and lorikeets although numerous other birds include emus, insectivorous birds to eagles which are also very common. Australian heathlands are also home to the world’s only nectar-feeding terrestrial mammal the Honey Possum; Tarsipes rostratus, from Western Australia.
Anthropogenic heath habitats are a cultural landscape that can be found worldwide and are better known as suburban gardens. They are typically mixed shrubs from all over the world combined in a scape for colour and texture.
Fire regimes with unnecessary recurring burning are frequently used to keep the heaths in check which is depleting the number of natural species in a given area. Those species affected by frequent burning included the various orchids, mosses and those plants that require large seed banks of short lived viable seeds. These plants usually require longer intervals between fires to replenish their seed stores taking 4 to 7 years to flower and seed and much longer to restore good quantities of seed to the soil. Many plants may suffer from the introduction of weeds into the area created by burning off at regular intervals and plant competition from plants that are more fire resistant or recover more quickly like Banksia specie which have lignotubers.
Many coastal low lying heaths will be affected by Global Warming if sea levels rise by 1 meter. This will drastically affect the salinity and water tables along the coastal fringe. High water tables will cause the deaths of all or most of the dry sand environment plants and salinity will cause the deaths of all the salt sensitive species. Inland species will be affected by drier and extended droughts which can also include increases in salinity of the soils.
Invasion of feral weeds is another huge problem facing heaths especially those on the frontal dunes and back dunes, many of which were planted by mining companies as restoration work and garden escapees.
Caves, karst and limestone habitats are important and display fascinating features which attract much interest from the biologist, geologist and archaeologist alike. Limestone soils are peculiar in Australia in that the soils are often shallow and have high pH values. Acid rain and Coral bleaching are often talked about with very little action or public debating eventuating.
Karsts are formed by the dissolution of limestone bedrock by ground water to produce a network of enlarged pipes and cavities through which the water prefers to flows. When these cavities are large enough to allow some form of access, they are known as caves. As a result, karstic landscapes are formed which is often relatively dry, with surface streams being seasonal or non existent with most the drainage taking place underground. In addition, they can have a range of surface features, including bare rock with fertile soils between, exposed crags and pavements, dolinas and poljes.
The vast Nullarbor Plain is the world’s largest limestone karst landscape covering an area of 270,000 square km, extending 2000 km between Norseman and Ceduna. Two thirds of the Nullarbor is within Western Australia and one third is in South Australia. The spectacular Bunda Cliffs and the Great Australian Bight are the southern border while the northern border is the Great Victoria Desert.
The name Nullarbor may mean “no trees”, but the plain is covered with bluebush and saltbush plants, hardy shrubs that are both drought and salt tolerant. The outer edges of the Nullarbor are the open woodland environments of Acacia specie.
The 1984 Biological Survey of the Nullarbor identified 794 vascular plant species 56 mammals; with one of Australia’s largest populations of southern hairy-nosed wombats, 249 bird species; including the endemic Nullarbor Quail and Nareth Blue Bonnet parrot, 86 reptile species and 1 amphibian within the study making it a rich source of native flora and fauna.
Some methods adopted by plants to survive limestone formations include:
* Plants have strong robust roots to penetrate the hard rock or large spreading roots to take advantage of the shallow soils.
* Plants have adapted to dry conditions with light seasonal winter rains.
* Plants are both saline resistant and adpt6 to high pH soils.
The level of visitor impacts have not been documented, but increasing tourism in the Nullarbor is resulting in damage close to the road side and 4 wheel drive access is damaging the land farther from the road. The Nullarbor continues to suffer with unrestricted access, because there is little on ground management. The dolines and caves are being affected the most.
Introduced feral animals such as rats, cats, camels, foxes and, especially rabbits are problematic eating native species faster than they can reproduce in many areas.
Australian limestone communities have been largely decimated near populous areas. The increase in fire frequency and intensity is a major concern with higher temperatures caused by global warming as will be the further reduction in rainfall. This is going to be a particularly worsening problem on the Nullarbor Plain where rainfall is expected to decrease to the west causing problems for the flora of the district. It is expected to increase slightly on the south eastern edges and as limestone is easily eroded the erosion could alter the landscape significantly exasperating the higher temperatures resulting in fungal attacks.
* Moisture requirements,
* Soil type,
* Soil pH,
* Salinity and
* Predation all contribute to a plants environment, habitat or niche where it survives.
* We are directly dependant upon the health of the environment and its habitats.
Further Comments from Members:
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In the spirit of reconciliation we acknowledge the Bundjalung, Gumbaynggirr and Yaegl and all aboriginal nations throughout Australia and their connections to land, sea and community. We pay our respect to their Elders past, present and future for the pleasures we have gained.