Exercises: The value of biodiversity

Explain what biodiversity is and name its three levels, giving an example of each.

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.

What is an endemic species? Give an example of fauna or flora from the Iberian Peninsula or the islands.

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.

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.

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).

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."

1. a) Refute the company's claim by explaining how this change will affect trophic networks and the variety of ecological niches in the ecosystem.
2. 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 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 Doñana marshes, an agricultural spokesperson states: "Water is only useful when it irrigates crop fields to produce food and jobs; letting it stay in the Doñana lagoons is wasting it because it does not produce any human benefit there."

1. 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.
2. b) Justify why Doñana must be protected based on its intrinsic value, regardless of any utility or economic benefit to humans.