Why Biodiversity Matters: Benefits and the Cost of Losing It

The free services of nature

What if you had to pay for every flower that got pollinated, every litre of water a wetland cleaned, and every tonne of soil held in place by roots? Nature does this work every day. Scientists call these benefits ecosystem services, and they depend on biodiversity.

Today you will assess: weigh up the benefits of biodiversity and what we lose when it shrinks.

Benefits of biodiversity

1. Ecosystem services

• Clean water: wetlands filter water as it moves through them, trapping soil and some pollution.
• Clean air: plants and algae release oxygen.
• Pollination of crops and wild plants.
• Healthy soil: decomposers recycle nutrients; roots hold soil in place and prevent erosion.
• Flood control: wetlands and forests soak up water during heavy rain and spring melt.
• Climate: forests, wetlands and peatlands store carbon, which helps slow climate change.

2. Food: crops, fish, wild berries, maple syrup, wild rice and much more.

3. Medicines: many medicines come from, or were first discovered in, living things. Penicillin, one of the first antibiotics, was discovered in 1928 by Alexander Fleming in a mould. A chemical in willow bark, used for pain by many peoples, including Indigenous peoples in North America, led scientists to develop aspirin. Every species lost could be a medicine never discovered.

4. Materials and jobs: wood, paper, cotton, wool. Forestry, fishing, farming and tourism provide jobs in many Ontario communities.

5. Culture, health and well-being: time in nature can help people feel calmer and healthier. Many cultures have deep connections to particular plants and animals. For many First Nations, Métis and Inuit people, the land, water, plants and animals are central to identity, language, teachings and ceremonies.

6. Resilience: as you learned, more diverse communities are better able to recover from disturbances.

Many people also believe that every species has value in itself, whether or not it is useful to humans.

Consequences of losing biodiversity

When biodiversity diminishes (gets smaller):

• Ecosystem services weaken: fewer pollinators means fewer fruits; lost wetlands mean more flooding and dirtier water.
• Food webs are disrupted: losing one species affects its predators, prey and partners.
• Communities become less resilient to diseases, invasive species and climate change.
• Possible medicines and foods are lost before we discover them.
• Jobs and economies suffer when fish stocks or forests decline.
• Cultures and ways of life are harmed when the plants and animals people rely on disappear.
• Extinction is forever. Once a species is gone everywhere, it cannot come back.

A lesson from the past: the passenger pigeon

The passenger pigeon once flew over Ontario and much of eastern North America in enormous flocks. People hunted them in huge numbers and cleared the forests they needed. Their numbers crashed. The last known passenger pigeon, named Martha, died in 1914 at the Cincinnati Zoo. The species is extinct.

Today, laws such as Ontario's Species Conservation Act, 2025 and Canada's Species at Risk Act aim to protect species at risk before it is too late.