reasons for maintaining biodiversity Flashcards
aesthetic reasons
-The presence of different plants and animals in our environment enriches our lives. For example, you might like to relax on a beach, walk in your local woodland or park or visit a rainforest.
• The natural world provides inspiration for people such as musicians and writers, who in turn provide pleasure for many others through music and books.
• Studies have shown that patients recover more rapidly from stress and injury when they are supported by plants and a relatively natural environment.
economic reasons
If biodiversity in an ecosystem is maintained, levels of long-term productivity are higher.
-Soil erosion and desertification may occur as a result of deforestation. These reduce a country’s ability to grow crops and feed its people, which can lead to resource- and economic-dependence on other nations.
• It is important to conserve all organisms that we use to make things. Non-sustainable removal of resources, such as hardwood timber, will eventually lead to the collapse of industry in an area.
Once all or enough of the raw material has been lost, it does not become economically viable to continue the industry. Note that even when ‘sustainable’ methods are used - for example replanting forest areas - the new areas will not be as biodiverse as the established habitats they replace.
• Large-scale habitat and biodiversity losses mean that species with potential economic importance may become extinct before they are even discovered. For example, undiscovered species in tropical rainforests may be chemically or medically useful. A number of marine species use a chemical-based defence mechanism. These are rich potential sources of new and economically important medicines.
• Continuous monoculture results in soil depletion - a reduction in the diversity of soil nutrients. It happens because the crop takes the same nutrients out of the soil year after year and is then harvested, not left for the nutrients to be recycled. This depletion of soil nutrients makes the ecosystem more fragile. The crops it can support will be weaker, increasing vulnerability to opportunistic insects, plant competitors, and microorganisms. The farmer will become increasingly dependent on expensive pesticides, herbicides, and fertilisers in order to maintain productivity.
• High biodiversity provides protection against abiotic stresses (including extreme weather and natural disasters) and disease.
When biodiversity is not maintained, a change in conditions or a disease can destroy entire crops. The Irish potato famine of the 1840s was a direct consequence of the reliance on only two varieties of potato. When a new disease spread to the area (the oomycete Phytophthora infestans), neither species contained alleles for genetic resistance, so the entire crop was destroyed. This led to widespread famine and the deaths of around 1 million people.
• Areas rich in biodiversity provide a pleasing, attractive environment that people can enjoy. Highly biodiverse areas can promote tourism in the region, with its associated economic advantages.
• The greater the diversity in an ecosystem, the greater the potential for the manufacture of different products in the future. These products may be beneficial to humans. For example, it may make food production more financially viable or provide cures or treatment for disease.
• Plant varieties are needed for cross breeding, which can lead to better characteristics such as disease resistance or increased yield. The wild relatives of cultivated crop plants provide an invaluable reservoir of genetic material to aid the production of new varieties of crops. Also, through genetic engineering, scientists aim to use genes from wild plants and animals to make crop plants and animals more efficient, thus reducing the land required to feed more people. If these wild varieties are lost, the crop plants may themselves also become more vulnerable to extinction. This is also important ecologically.
ecological reasons
• All organisms are interdependent on others for their survival.
The removal of one species may have a significant effect on others, for example a food source or a place to live may be lost.
For example, decomposers break down dead plant and animal remains, releasing nutrients into the soil, which plants later use for healthy growth. Plants rely on bees for pollination - this is important for both wild plant species and commercially produced crops. Fruit farmers use bees to pollinate their crops; a decrease in
the wild bee population would decrease crop yields.
-Some species play a key role in maintaining the structure of an ecological community. These are known as keystone species.
They have a disproportionately large effect on their environment
relative to their abundance (in terms of their biomass or productivity). They affect many other organisms in an ecosystem and help to determine the species richness and evenness in the community. When a keystone species is removed the habitat is drastically changed. All other species are affected and some may disappear altogether. It is therefore essential to protect keystone species to maintain biodiversity. (See the Application for examples of keystone species.)
human activity versus biodiversity
we have discussed the negative impact humans have on biodiversity. such as deforestation and clearing land for monoculture. However. human activity also plays an important role in increasing biodiversity.
In many countries, including the UK, the natural habitat is created by human intervention and the management of land. For example, farming, grazing, planting of hedges, meadows, and forest management have changed the landscapes, the habitats and the ecology over thousands of years. Even the wildest of habitats, such as Dartmoor and the Scottish mountains, are a result of farmers and landowners managing the ecosystems.
One example is sheep grazing on downlands. This enables rare species like the Glanville fritillary (an orange patterned butterfly) to survive.
By maintaining the grass at low levels it allows the plantains that the caterpillars feed on to thrive and therefore maintains biodiversity.
Research has also shown that after annual controlled burning of gorse and heather in the New Forest (an area of lowland heath), biodiversity soars. If left to its own devices, bracken and pioneer tree species such as pine and silver birch would start to dominate. Areas of lowland heath worldwide are now rarer than rainforest and provide habitats for rare UK bird and reptile species such as the nightjar and sand lizard.
