BiodiversityBiodiversity The variety of species present. is a hot topic these days. All around us, there’s talk of Earth’s beautiful animals creeping ever closer to extinction. Leopards, gorillas, rhinos, and sea turtles are charismatic creatures that often take center stage in conversations about loss of wildlife. But these animals are only a tiny sliver of the plants and animals that are approaching extinction. Today, nearly 1 million species are threatened to become extinct within a human lifetime[1]. No matter their size or dazzling appearance, all native species contribute to their local community and help keep the planet healthy.
For many people, plants and animals are important for their intrinsic value. But nature is also a critical source of income and supplies needed for human survival. Farming, forestry, growing cities, weeds, and pests are some of the reasons for the rapid loss of plant and animal species. Why should we care that species are going extinct? To answer that question, we must first understand what biodiversity is and how ecosystems work.
Biodiversity is all the different creatures living in one area.
Biodiversity is the mix of different animals, plants, fungi, and microorganisms that make up our natural world[2]. For example, a forest containing many types of trees, dozens of bird species, and both big and small mammals, is described as having high biodiversity. In contrast, a forest having just one type of tree, only two bird species, and a single type of mammal, is described as having low biodiversity. Biodiversity describes how many types of organisms are living in a single location. It’s not how many individual organisms are currently living there. As creatures go extinct, biodiversity goes down which causes problems in the surrounding ecosystem.
An ecosystem is a network of organisms working together in the same environment.
An ecosystem is a community of plants and animals interacting with each other and their physical surroundings. Plants absorbing sunshine, dead things decomposing, and animals eating plants and other animals are some of the activities that happen in an ecosystem. Ecosystems can be big – Oregon’s Willamette National Forest – or small – a single tide pool on the Pacific coast. No matter their size, ecosystems need many types of creatures because every plant and animal has a job to do.
How does biodiversity relate to ecosystems?
Ecologists group organisms together according to the general role they play in an ecosystem. These groups are producers, consumers, and decomposers. These groups can be subdivided further to describe complex webs of activity. For an ecosystem to function properly, it must have many types of creatures from each group – high biodiversity – so all the ecosystem activities happen.
Examples of organisms and the job they do for their ecosystem:
- Opossum: This mammal is a consumer who eats ticks. Ticks can spread disease throughout an ecosystem. Without opossums, the number of ticks can grow, making other animals sick with diseases like Lyme disease.
- Clover: This plant is a producer that takes nitrogen from the air and puts it in the soil. Without clover, other plants wouldn’t be able to absorb the nitrogen they need to grow.
- Earthworm: This invertebrate is a decomposer. By eating dead things, the earthworm moves nutrients from an organism into the soil. Without decomposers, like earthworms, plants wouldn’t be able to access the materials they need to grow.
- Snowberry: This Oregon plant is a producer that provides food for birds and insects in the winter. Not many plants have berries in the winter, so snowberry is an important food source for animals living in Oregon all year long.
- Mussels: This consumer is a filter feeder that keeps streams and rivers clean. Without mussels, toxic chemicals, algae, and bacteria can build up in the water, making it hard for aquatic animals to survive and the water unsafe to drink.
In an ecosystem with high biodiversity, there are many different creatures doing similar jobs. For example, mussels have other filter feeder neighbors to help clean the water. When biodiversity is low, there are fewer organisms working together to complete a job. If a job stops being done or isn’t done enough, side effects ripple through the ecosystem causing problems along the way.
Ecosystems are like a sports team.
To help us understand ecosystems, we can compare them to a sports team. Sports teams are often divided into groups. Several players make up each group and work together to do a job that helps the team compete. Think about a soccer team. Instead of producers, consumers, and decomposers, a soccer team is divided into forwards, defenders, midfielders, and goalkeepers.
- Forwards try to score goals into the other team’s net.
- Defenders try to prevent the other team from scoring goals.
- Midfielders support the forwards and the defenders by helping with both scoring and defending.
- Goalkeepers are the last line of defense in preventing the other team from scoring.
If one member of a group leaves the game, another player is around to keep their group working. What happens when more than one player leaves the game? Then there are fewer teammates available to do their group’s job. The remaining players need to work harder to overcome their disadvantage. As the game goes on, these players will become tired and struggle to fulfill their role. Once that happens, the opposing team can win more easily. Just like how a sports team is stronger with many players, an ecosystem is stronger with many species.
Why does biodiversity and ecosystem health matter to us humans?
Biodiversity keeps ecosystems healthy, and ecosystems keep humans healthy. The health and safety benefits people get from nature are called ecosystem servicesEcosystem Services The benefits that the environment provides for human communities, such as food, filtering air and water, and decomposing waste.. An example of an ecosystem service is how trees make oxygen. By doing so, trees clean the air we breathe. In areas with few trees and lots of pollution, the air gets hazy and can be dangerous to inhale. Another example is the way wetlands, marshes, and swamps act like giant sponges. They absorb and slow down large amounts of rainwater which prevents flooding and removes pollution from the water.
Most of these benefits aren’t obvious until they go away. When many ecosystem services are lost, the negative effects become more visible and extreme.
Biodiversity protects human health.
Just like birds and mammals, parasites, viruses, and bacteria are natural members of an ecosystem. In a healthy system, these potentially harmful organisms don’t cause many problems because they are kept in check by their environment. When an ecosystem becomes unbalanced, disease-causing organisms can grow out of control and spread to humans.
A good example of this is when mosquitos create malaria outbreaks. In 2019, malaria caused roughly 409,000 human deaths[3]. This tragic loss of life is linked to the way humans have altered forest ecosystems.
Cutting down forests and harvesting trees for timber causes more sunlight to reach the ground. The sunlight then warms streams and ponds. Because there are fewer trees to soak up water, the ground becomes wet and swampy. Warm, wet conditions are ideal for mosquito reproduction. Soon, there are millions of mosquitos carrying the malaria pathogen that can be spread to humans when a person is bit. This is just one example; scientists estimate that 60% of human-harming diseases come from wild animals and livestock[4].
Biodiversity helps farmers grow food.
Agricultural fields aren’t natural, but they do function like ecosystems and are healthiest with high biodiversity. Almonds, apples, avocados, blueberries, carrots, and onions are a few of the crops that rely on pollination by wild insects. Non-pollinating insects are important too. Predatory insects like ladybugs eat pests that want to eat crops. These beneficial insects need food, water, and shelter which can be hard to find in miles of fields. A farm with high biodiversity provides habitat by growing many types of crops and planting native plants. A high variety of crops, grasses, and shrubs occupying a farm increases the number of helpful insects that live there. More helpful insects result in more food being grown and less use of chemicals that can cause pollution.
Biodiversity helps communities adapt to climate change.
Ecosystems with high biodiversity can recover from disturbances better than ecosystems with low biodiversity. This means healthy ecosystems are more likely to continue to support humans even as the earth goes through extreme changes. Changes to the earth’s climate are happening so fast, it’s hard for our communities to make big – often unpopular – adjustments needed for our species to survive. Healthy, biodiverse ecosystems buy us time to adapt to climate change by providing buffers against natural disasters like wildfire, flood, and drought.
More resources:
- Video – How do wolves change rivers?
- Blog Post – Nature vs Nature: Biocontrols in Conservation
- Quick Read – 6 Ways to Preserve Biodiversity
[1]Global Assessment Report on Biodiversity and Ecosystem Services (2019), Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services.
[2] Lorin Hancock, World Wildlife Fund. https://www.worldwildlife.org/pages/what-is-biodiversity
[3] World Malaria Report (2020), Global Malaria Programme – World Health Organization. https://www.who.int/teams/global-malaria-programme/reports/world-malaria-report-2020
[4] How Forest Loss is Leading to a Rise in Human Disease (2016), Jim Robins. https://e360.yale.edu/features/how_forest_loss_is_leading_to_a_rise_in_human_disease_malaria_zika_climate_change
[5] Oregon White Oak and Wildlife, Tools for Family Forestland (2018), Ahr, N., Ahr M., Bevis, K., Cafferata Coe, F. https://knowyourforest.org/sites/default/files/documents/Oregon%20White%20Oak%20and%20Wildlife.pdf