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A2 Biology ILU
Transcript of A2 Biology ILU
Conservation and preservation
Management and reclamation
Reasons for conservation
Effects of human activities on the Galapagos
How are conservation and preservation different, give examples of each.
Explain how the management of an ecosystem can provide resources in a sustainable way, with specific references to timber production in a temperate country.
What are the social and ethical reasons for conservation of biological resources, give specific examples of each.
Outline, with examples, the effects of human activities on the animal and plant populations in and around the Galapagos.
How has the environment been changed since the increase in population and tourism and what steps have been taken to prevent further damage and reverse that which has already been done.
Include both land and marine environments.
Explain how conservation is a dynamic process involving management and reclamation, distinguishing between the two.
Sustainable management is where the exploitation of resources causes minimal damage to the ecosystem, allowing the population sizes of species to remain fairly stable.
More intensive methods used to exploit the environment for resources has disrupted and destroyed some ecosystems, reducing the biodiversity.
This involves cutting a tree trunk close to the ground to encourage new growth.
This is where the tree trunk is cut higher up. It is used when the population of deer for example, is high.
This is where the wood is divided into sections, and one section is cut each year allowing new stems time to mature.
Rotational coppicing benefits the biodiversity. It helps to provide different types of habitat in the different areas, where more light could be apparent in the habitat increasing the number and diversity of species.
The length of rotation varies depending on how long it takes time for the stems to mature, and on the dimensions of wood required.
Standards are trees which are left to grow larger. They are used to supply larger pieces of timber.
LARGE-SCALE TIMBER PRODUCTION
Rarely done in UK due to destruction of habitats.
Reduces soil mineral levels resulting in area being susceptible to erosion.
Trees usually the water from the soil, preventing the soil from being washed away, and also help to maintain soil nutrient levels
If you leave each section of woodland to mature for 50-100 years before felling, there can be increased biodiversity. However, this time scale is not cost-effective.
Modern Sustainable Forestry Principles:
Any tree harvested is replaced by another one.
As a whole, the forest must maintain its ecological function regarding its biodiversity, climate and mineral/water cycles.
Local people should be able to derive benefits from the forest.
SUSTAINABLE MANAGING A WOODLAND
Sustainable managing a woodland involves a balance between harvesting wood to make the woodland pay for itself, and conservation enabling a continuous supply of wood to maintain the biodiversity.
Fewer trees will need to be harvested if each tree supplies more wood.
This can be achieved by,
only plant species which will grow well
positioning trees an optimal distance apart.
Establishing protected areas
Green Belt land
Legal protect to the endangered species, or ex-situ conservation.
Careful management to maintain a stable community, or even reclaim an ecosystem.
Management strategies include:
Raising the carrying capacity by providing extra food.
Encouraging a natural dispersion of individuals between fragmented habitats. This is done by developing dispersal corridors of appropriate habitats.
Restrict where individuals can go by use of fences.
Controlling predators and poachers
Vaccination against disease.
Preserving habitats by preventing pollution or disruption.
Intervene to restrict the progress of succession.
"Every species has its own rights, irrespective of its financial value to us."
"All living things have a right to survive, and humans have an ethical responsibility to look after them."
"It is economics which drive the arguments in favour of human activities which work against conservation."
"If you express the value of conservation in economic terms, it is more effective to make it a priority."
"Many species are a valuable food source. Genetic diversity in wild strains may be needed in the future for resistance or increased yield."
"There are many potential beneficial resources, such as medicinal drugs which can be discovered in natural environments."
"The natural predators of pests can act as biological control agents."
"There is usually an indirect economic value from many species such as the economic benefits from tourists who wish to see the specific species."
"There is evidence that a reduction in biodiversity may result in a less stable climate, which could result in droughts or flood, and the associated economic costs.
"There is a significant social and financial value from ecotourism and recreation."
The maintenance of biodiversity, including diversity between species, genetic diversity within species, and maintenance of a variety of habitats and ecosystems.
Example of conservation is....
A way to maintain the biodiversoty, which usually involves protecting areas of land, as yet unused by humans, their 'untouched' form.
Example of preservation is...
EFFECTS OF HUMAN ACTIVITIES
Fishing/ hunting has led to a significant decrease in the native species of the Galapagos Islands.
Humans has harvested species faster than they can replenish themselves.
The Galapagos Tortoise has been used as a food resource, and many species were hunted to extinction. Out of the species still in existence, only 3 are reproducing at a rate that means they will survive in the long-term.
The development of eco-tourism has resulted in increased pollution.
The boats which transport tourists to and from destinations have sometimes suffered from oil spillages.
The oil spillages cause both marine iguanas and seals to die as a result. The oil spill in 2001 has an adverse effect on both marine and coastal ecosystems.
The introduction of new species has had a dramatic effect on existing communities.
Goats have eaten the vegetation, and have become competition with the tortoises and land iguanas for the food resource.
The introduction of pigs has destroyed the delicate ecosystems on Galapagos because of the pigs digging for plant roots.
Any eggs on the ground have been eaten by rats, so there has been a reduction in nesting birds as a result.
Cats have become direct predators on any ground-nesting species.
A plant introduced has been the red quinine tree on Santa Cruz Island which has spread rapidly due to its wind-dispersed seeds. The ecosystem has now become a closed forest canopy (previously low shrub and grassland, and the native Cacaotillo shrub has been almost eradicated. This has also led to some birds such as the Galapagos Petrel losing their nesting sites.
INCREASED POPULATION AND TOURISM
In the past few decades, there has been a significant increase in population in reaction to the the development of tourism in the Galapagos Islands.
Between 1980 and 2005, the population has increased by 23000, from 5000 to 28000. In this same time period, the number of tourists visiting the islands each year has increased by 96000, from 4000 to 100000.
But the conservation of pandas has caused some split opinions....
An increase in population has subsequently resulted in more fishing. In more recent years there has been a boom in fishing for exotic fishing. This boom has left some species seriously depleted such as the sea cucumber population. This then has a drastic effect on other species due to the specific food web for this eco-system.
There as also been an international market for shark fin, leading to the deaths of 150000 sharks each year. 14 of these species are listed as endangered.
An increase in population has had a negative impact on the native species of the Galapagos Islands.
Non-native species such as goats, cats, pigs and fruit or vegetable plants have been brought to the islands. These species have been out-competing the local species for food and shelter, and have also brought diseases such as avian malaria and bird flu. Native species do not have capability of surviving from these diseases and this decreases the size of the native species populations on the islands. This is because they have evolved and thrived where there has been very little predation or competition between species.
Goats are significantly damaging. Not only do they eat unique species such as the Galapagos rock purslane, they also out-compete tortoises for food supply and damage their nesting habitats. On some islands such as the Northern sabella Island, the goat has changed the forest into grassland, which had led to soil erosion.
Due to the remteness and the relatively recent discovery and settlement by humans, 95% of the native species remain intact however, it is this same reason which makes the native species so vulnerable to 'alien' species.
With an increased population and the growth of tourism, there has been an increased need for infrastructure and a need for agricultural land. This has resulted in the destruction and fragmentation of habitats. An example is the forests of Scalesia trees and shrubs (unique to the islands) being almost eradicated on Santa Cruz for agricultural land.
PREVENTING FURTHER DAMAGE
Removing introduced species
Controlling invasive species was one of the most pressing challenges identified by the World Heritage Committee when it recommended that the Galapagos be placed on the list of World Heritage in Danger.
Both scientist and conservationist agree that ntroduced plants and animals are the single greatest threat to the ecosystems of the Galapagos.
Initial efforts were focused on goat populations, but by the 1980s, with the increasing population and tourism, stopping any new introductions was of equal importance.
The Charles Darwin Foundation (CDF) played a leading role in establishing the Galapagos Inspection and Quarantine System (SICGAL). This was responsible for the inspection of cargo, as wells as the bags and luggage of tourists.
The implementation of education programmes on the inhabited islands increased awareness of the threat of introduced species, and the participation in the fight against any invasive species.
In 2002, natural enemies were used to reduce the damage caused by invasive species such as the cottony cushion scale (an insect). 60 native and endemic plant species were under threat. After 6 years of intensive research to determine the probability of success and any impacts, the Australian ladybug, Rodolia cardialis, was released. This has proved effective at reducing the scale population to a managable level.
There has been success, through the method of culling, in eradicating feral goats on Isabella Island, and pigs on Santiago Island.
Introducing species to the islands is another initiative.
An example s the Espanola tortoises which have been moved to Pinta. (There was only one tortoise left in Pinta.
To try and limit the numbers of tourists visiting the Galapagos Islands every year, landing fees have been increased.
Prevention and Awareness:
The inspection capabilities of the Galapagos Inspection and Quarantine System has been strengthened through improved training and equipment.
The Community Monitoring Projects (CMPs) have been expanded to achieve greater involvement from the local population in identifying and responding to new invasive species.
Education programmes in schools and Environmental Education Centres has been strengthened.
•The maintenance of biodiversity, including diversity between species, genetic diversity within species, and maintenance of a variety of habitats and ecosystems whereas preservation is a way to maintain biodiversity, which involve protecting land, as yet unused by humans leaving them in their ‘untouched’ state.
•Sustainable management means that there is minimal damage to the ecosystem, allowing for stable population sizes.
•Timber production can include the methods coppicing and pollarding. Large-scale timber production can include clear-felling, but this is extremely destructive of habitats.
• Sustainable managing woodland is where there is a balance between harvesting wood and the conservation, allowing for a continuous supply of wood, but still maintaining the biodiversity.
•Conservation involves establishing protected areas, using legal protection on endangered species and careful use of management strategies.
•Ethical reasons to conserve biological resources include ideas that all species have their own rights, irrespective of financial value and that humans have a responsibility to look after them
•Social reasons for conservation include the potential for future medicines the indirect economic value due to tourism and the unwanted detrimental effects from a reduction in biodiversity.
•Human activities in the Galapagos Islands have had an effect on the number of native species due to fishing/ hunting, increased pollution and the introduction of new species has had an dramatic negative effect on existing communities.
•Increased population and tourism has changed the environment in a number of ways such as depletion in fish populations and sharks, changing the underwater ecology of the Galapagos. Introduced species have out-competed native species for food and habitats, and the need for infrastructure and agricultural land has resulted in the destruction and fragmentation of habitats.
•In order to prevent further damage in the Galapagos Islands, there has been initiatives to control and remove invasive species, re-introduce native species to the various islands and an attempt at limiting the number of tourists visiting the Galapagos each year.