What are the pressures on biodiversity?
A species usually has a specific function, or niche, in an ecosystem. If a species dies out, another will eventually replace it. But human activities are not just destroying species; they are destroying their niches as well.
- Habitat loss
- Invasive species
- Pollution and waste
- Over-exploitation of renewable resources
- Climate change
Habitat loss
Losing habitats is the greatest threat to biodiversity. According to the
Millennium Ecosystem Assessment, over the past 50 years people have changed
ecosystems faster and more extensively than in any period in human history.
Rapidly growing demands for food, freshwater, timber, and fuel drive this
change. Humans commandeer an enormous amount of the planet's productivity
- experts estimate we use up to 40% of
all plant growth on land, and 25-30% of
marine production, putting enormous pressure on biodiversity.
Habitat restoration is a way of improving degraded ecosystems or creating new areas to compensate for loss of habitat elsewhere. Both types of operation depend on an understanding of the interactions between species present. NERC's Centre for Ecology & Hydrology aims to understand these processes and to use the information to develop methods for restoration of habitats. Research has concentrated on heathland management, downland restoration, Chernobyl's legacy and grazing management.
Invasive species
Invasive species are organisms that thrive after they are accidentally or intentionally transplanted from one ecosystem to another. When invasive species enter an ecosystem, they occupy habitats and compete for food. Often people are responsible for this by introducing exotic plant species into their gardens that then escape into the wild. One in five of the UK's wild flowering plants arrived by this route.
Pollution and waste
The oceans, rivers, lakes and lands have become rubbish bins for society's industrial and organic waste. Nature can disposes of some of our waste - some micro-organisms are very adept at breaking down toxic chemicals - but large volumes overwhelm the Earth's capacities to absorb, transform or break down pollutants.
Over-exploitation of renewable resources
Societies have drastically reduced some fish populations, hunted some whales to the verge of extinction and destroyed whole forests and their ecosystems.
Climate change
The world is split into many well-established climate zones for example: the poles, deserts and temperate zones. These areas may shift as the planet warms. How will species adapt to these changes? Will they be able to move if the change happens quickly? For some species there will no longer be anywhere suitable to live. For more details see the climate change pages.
