Biodiversity

1. What Is Biodiversity?

Before we can begin to discuss biodiversity, recall that an ecosystem is is the living and nonliving components that interact in a given area.

Biodiversity is the number and relative abundance of a species in a given area. The concept of biodiversity can also be extended to include the entirety of global biodiversity, or the number and relative abundance of species worldwide. 

Biodiversity is important because, on a large scale, it supports and increases stability across ecosystems. Each species plays a different role in an ecosystem, and all are interdependent on each other for the healthy functioning of the whole. Even the loss of a single species in an ecosystem could have unforeseen widespread consequences, including the loss of other species.

IN CONTEXT

An example of such a scenario is the disappearance of coral reefs. Across the world, coral reefs are disappearing because of global warming faster than forests are disappearing because of deforestation. If they were to go completely extinct, it would have widespread effects. Thousands of aquatic species make their homes in and around coral reef systems. Without the coral reef systems, those species will be threatened, and entire ecosystems will be weakened, essentially creating a ripple effect of damages. The result will impact fisheries and reduce human economic and food sources.

term to know

Biodiversity

The number and relative abundance of a species in a given area.

2. Ecosystem Services

As mentioned, biodiversity is key to maintaining the health of an ecosystem. Ecosystems themselves provide many benefits to humans, which are called ecosystem services. The following are four main categories of ecosystem services.

• Provisioning services, such as providing food, fiber, fuels, fresh water, and medicines 
• Regulating services, such as climate regulation, water purification, and pollination 
• Cultural services, such as being of religious or spiritual value, aesthetic value, and having recreational or educational use  
• Supporting services, such as nutrient cycling, soil formation, and production of energy from sunlight

IN CONTEXT

Different parts of ecosystems provide different types of services. An example of an ecosystem service would be what plant species provide through photosynthesis: oxygen. Without this service, the atmosphere's mixture of different gases would become imbalanced. Humans require a certain mix of oxygen in the air to breathe and perform respiration. Without plants, there wouldn't be enough. The free oxygen that plants produce also eventually turns into atmospheric ozone, which is necessary to protect humans from UV radiation. Plants also absorb carbon dioxide, which buffers against the greenhouse effect and global climate change.

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Ecosystem Services

The benefits people obtain from ecosystems.

3. Sixth Mass Extinction

Recall that many scientists consider the current era of human population growth to be the sixth mass extinction, or the Holocene extinction. This era includes the last 12,000 years to the present. In that time, it is estimated that somewhere between 500,000 and one million species of birds, mammals, reptiles, amphibians, plants, and insects have gone extinct from overharvesting, habitat degradation, and pollution from human population growth and activities. In particular, there has been a sharp increase in extinctions over the past few centuries. However, it has been debated whether these extinctions constitute a sixth mass extinction.

reflect

Many Indigenous communities view biodiversity not just as resources but as relatives in a living system. How might this worldview shape conservation efforts?

did you know

The currently observed global extinction rates are 10s to 1000s of times higher than the average over the last 10 million years and are still accelerating, with upwards of 1 million species threatened by extinction. Some experts estimate that we are losing between 0.01% and 0.1% of all species to extinction each year, and the United Nations projects that more than half of all human-era species may become extinct by 2050.