The value of biodiversity
Walk along the shore at Dublin Bay or through an oak wood in Killarney National Park: no two gulls, no two oak trees and no two ponds are identical. That variety is not a decoration on the planet: it is what keeps it standing. When it disappears, we feel the effects even if we do not notice straight away. At the end of this page, we will see why a wood with many species copes better when things go wrong.
The three levels of biodiversity
If you walk along the Irish coast, you see gulls with slight differences in their plumage, rock pools with different fish, crabs and algae, and cliffs bordering dunes and salt marshes. At what levels is all that variety of life organised?
Explain what biodiversity is and name its three levels, giving an example of each.
Explain what biodiversity is and name its three levels, giving an example of each.
What is an endemic species? Give an example of fauna or flora from the Iberian Peninsula or the islands.
What is an endemic species? Give an example of fauna or flora from the Iberian Peninsula or the islands.
Explain in your own words the difference between species diversity and ecosystem diversity, and give an example of each.
Explain in your own words the difference between species diversity and ecosystem diversity, and give an example of each.
What biodiversity gives us
Types of value
Ecosystem services are also called regulating (water purification, flood and storm protection, climate, pollination), provisioning (food, timber, medicines), supporting (soil formation) and cultural (recreation, tourism, beauty). The value of biodiversity can also be seen in three ways:
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Direct and indirect value: products we use (honey, timber) and services we benefit from without harvesting anything (shade, water purification).
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Potential (option) value: species not yet studied may hold future medicines or materials. Many medicines come from plants, fungi or bacteria, so an extinction can destroy a discovery before it is made. Note also that more plant biomass does not mean more biodiversity: a plantation of one fast-growing tree may store carbon quickly, but it offers few niches and a simple food web, so few species can live there. For example, the antibiotic penicillin was discovered in a mould, so an unstudied mould or soil bacterium that dies out may take a future medicine with it.
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Intrinsic value: living things have a value of their own, whether or not they are useful to us.
Habitats can also act as a nursery for young animals: for example, estuaries and salt marshes shelter young fish before they move out to sea, and a coastal forest such as a mangrove does the same in warmer countries. Mangrove roots also slow waves and protect the coast from storms, so destroying a mangrove removes both the coastal defence and the nursery. Destroying the habitat removes the nursery and the fish stocks that depend on it. Habitats also earn money through ecotourism: birdwatchers, walkers and anglers spend money in local shops, B&Bs and pubs, so this economic value gives people a reason to protect the habitat.
Ecosystems provide us with ecosystem services free of charge, such as crop pollination, water purification, or fertile soil formation. Name two of these services and…
Ecosystems provide us with ecosystem services free of charge, such as crop pollination, water purification, or fertile soil formation. Name two of these services and explain what one of them involves.
Name two iconic species of Irish wildlife and explain why they are used as symbols in conservation campaigns.
Name two iconic species of Irish wildlife and explain why they are used as symbols in conservation campaigns.
Name two products we obtain thanks to biodiversity (food, medicines, materials) and state which living thing each one comes from.
Name two products we obtain thanks to biodiversity (food, medicines, materials) and state which living thing each one comes from.
Distinguish between the direct and indirect value of biodiversity and classify these examples: honey, the shade of a forest that cools a valley, the timber of an oak…
Distinguish between the direct and indirect value of biodiversity and classify these examples: honey, the shade of a forest that cools a valley, the timber of an oak tree, and the water purification carried out by a wetland.
A large proportion of the crops we consume depend on pollinating insects such as bees. Explain what would happen to food production if they disappeared, and what this…
A large proportion of the crops we consume depend on pollinating insects such as bees. Explain what would happen to food production if they disappeared, and what this teaches us about the value of biodiversity.
Many medicines come from substances discovered in plants, fungi, or bacteria. Explain what is lost when a species that has not yet been studied becomes extinct (the…
Many medicines come from substances discovered in plants, fungi, or bacteria. Explain what is lost when a species that has not yet been studied becomes extinct (the potential value of biodiversity).
Mangrove forests protect coasts from storms and serve as a nursery for countless fish. Relate these functions to the value of biodiversity and reason what is lost when a…
Mangrove forests protect coasts from storms and serve as a nursery for countless fish. Relate these functions to the value of biodiversity and reason what is lost when a mangrove forest is destroyed.
Birdwatching tourism generates income in districts with well-preserved wetlands. Explain how this economic value can become an argument for protecting biodiversity.
Birdwatching tourism generates income in districts with well-preserved wetlands. Explain how this economic value can become an argument for protecting biodiversity.
In a rural region, it is proposed to eliminate subsidies for muladares (feeding stations for scavenging birds), arguing that vultures "contribute nothing to the regional…
In a rural region, it is proposed to eliminate subsidies for muladares (feeding stations for scavenging birds), arguing that vultures "contribute nothing to the regional economy because they produce neither meat nor milk."
- a) Classify the type of ecosystem service provided by vultures and justify why their disappearance would cause an unavoidable additional economic cost for livestock farmers and the municipality.
- b) Predict two ecological and health consequences that the region would suffer if livestock carcasses were left in the fields for weeks without the intervention of scavenging birds.
A city council plans to drain a hypersaline wetland to build an industrial estate, claiming that "it is just a foul-smelling, unproductive mudflat where no species of…
A city council plans to drain a hypersaline wetland to build an industrial estate, claiming that "it is just a foul-smelling, unproductive mudflat where no species of interest live." However, a team of microbiologists has just isolated a bacterium in that wetland with an enzyme capable of synthesizing bioplastics from agricultural waste.
- a) Refute the city council's position by applying the concept of the potential or option value of biodiversity.
- b) Justify what irreversible scientific and industrial consequences arise from the destruction of extreme habitats before their microscopic biodiversity has been researched.
Earthworms and soil fungi are not "attractive" species, but without them forests would not work. Use this example to reason why biodiversity is not valued only for its…
Earthworms and soil fungi are not "attractive" species, but without them forests would not work. Use this example to reason why biodiversity is not valued only for its best-known species.
A company plans to build a tourist resort on a coastal dune ridge where protected birds nest, claiming that "the dunes are just unproductive sand and the 200 jobs…
A company plans to build a tourist resort on a coastal dune ridge where protected birds nest, claiming that "the dunes are just unproductive sand and the 200 jobs created by the hotel more than compensate for their disappearance."
- a) Identify two essential regulating ecosystem services provided by dunes and predict what will happen to the beach and to the seafront promenade itself during winter storms if the dunes are destroyed.
- b) Refute the company's position using the concept of the intrinsic value of biodiversity and reason why short-term economic benefits cannot compensate for an irreversible biological loss.
It is proposed to label supermarket products according to their impact on biodiversity, as is already done with the energy efficiency of household appliances. Analyse…
It is proposed to label supermarket products according to their impact on biodiversity, as is already done with the energy efficiency of household appliances. Analyse two advantages and one difficulty of the measure and conclude with your opinion.
Genetic diversity, extinction and stability
After a dry summer, a uniform plantation of Sitka spruce is badly damaged, while a nearby riverside woodland by the Shannon with willows, ash trees, elms and shrubs survives with hardly any damage. Why do two plant communities respond so differently to the same adversity?
Back to the start: the riverside woodland survives because its many species include some that tolerate the dry spell, while the plantation has only one.
What is genetic diversity? Explain why a population with high genetic variety withstands a disease better than one with little.
What is genetic diversity? Explain why a population with high genetic variety withstands a disease better than one with little.
Explain what it means for a species to be in danger of extinction and cite one frequent cause of this situation.
Explain what it means for a species to be in danger of extinction and cite one frequent cause of this situation.
An ecosystem with many species tolerates a drought or a pest outbreak better than one with few species. Reason why, using the idea that if one species fails, others can…
An ecosystem with many species tolerates a drought or a pest outbreak better than one with few species. Reason why, using the idea that if one species fails, others can fulfill its function.
Some old varieties of wheat withstand drought better than modern ones. Explain why conserving traditional varieties and the wild relatives of crops is an investment for…
Some old varieties of wheat withstand drought better than modern ones. Explain why conserving traditional varieties and the wild relatives of crops is an investment for the future.
A logging company proposes replacing a mixed native forest with a clonal plantation of fast-growing eucalyptus, claiming that "by generating more plant biomass per year,…
A logging company proposes replacing a mixed native forest with a clonal plantation of fast-growing eucalyptus, claiming that "by generating more plant biomass per year, the plantation will capture more CO2 and improve the surrounding biodiversity."
- a) Refute the company's claim by explaining how this change will affect trophic networks and the variety of ecological niches in the ecosystem.
- b) Predict, with reasoned arguments, how each of the two forest stands will respond to the arrival of an insect pest or a period of extreme drought.
The graph shows the results of an experiment: two grasslands, meadow A with twelve plant species and meadow B with only three, experience the same drought, and the…
The graph shows the results of an experiment: two grasslands, meadow A with twelve plant species and meadow B with only three, experience the same drought, and the percentage of their initial production maintained by each is measured. Interpret the data in the graph and relate them to ecosystem stability.
During a debate on the overexploitation of the aquifer that feeds the Shannon Callows marshes, an agricultural spokesperson states: "Water is only useful when it…
During a debate on the overexploitation of the aquifer that feeds the Shannon Callows marshes, an agricultural spokesperson states: "Water is only useful when it irrigates crop fields to produce food and jobs; letting it stay in the Shannon Callows lagoons is wasting it because it does not produce any human benefit there."
- a) Refute this argument by explaining to the spokesperson what ecosystem services are and provide two specific examples of direct or indirect benefits that the marshes provide to society.
- b) Justify why the Shannon Callows must be protected based on its intrinsic value, regardless of any utility or economic benefit to humans.
The number of butterfly species is counted in three meadows under different management: an unmown meadow (38 species), a meadow mown once a year (25 species), and a lawn…
The number of butterfly species is counted in three meadows under different management: an unmown meadow (38 species), a meadow mown once a year (25 species), and a lawn mown every week (7 species). Interpret the data, relate them to the management of each meadow, and reason which one will provide better services such as pollination.