Human Impacts on Species and Ecosystems

Welcome back to Beyond’s Geography Blog! This entry focuses on the Human Impacts on Species and Ecosystems, exploring deforestation and reforestation.

We’ll be looking at how human activities are responsible for the decline of all species of animals, plants and trees in the world. Exploring how agriculture is responsible for a substantial proportion of greenhouse gas emissions in the UK.

Learn about the role of crop production and how a decline in pollinator species could cause food shortages for humans and animals. 

So, get ready to learn about the importance of ecosystems and consider how forests are extremely important as they support all forms of life, and produce oxygen and food. 

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Human Impacts on Species and Ecosystems


Forests are extremely important ecosystems – they support human, animal, insect and plant life, absorb carbon, produce oxygen and food, provide medicinal and health benefits, and can be a source of income. It is reported that around 28 thousand species of plants found in forests are used for medicines; making forests an essential global asset.


Human activity is causing forests to shrink. Between 2010 and 2015, ten million hectares of trees were removed each year. It is estimated that two thousand years ago 80% of Western Europe was covered by forests. Today, only 34% of the same area is forested.


Reforestation can counteract the issue by replacing lost trees (although they are not necessarily planted in the same location). Between 2010 and 2015, 5 million hectares of trees were planted globally, approximately half of the number cut down in the same timeframe. This is a long-term strategy as each tree has to grow for 10 to 20 years before it begins to make a significant impact on the environment.

Even while they are still growing, trees can have huge benefits to the environment such as improving air quality, regulating water cycles, reducing Earth’s surface temperatures and improving soil quality. They provide habitats and food for animal and insect species, as well as reduce stress and improve mental health in human populations.

Species Decline

Human activities are responsible for the decline of all species of animals, insects, fish, reptiles, corals, plants and trees in the world. Some of these species are now facing extinction. 

Species populations do fluctuate and sometimes become extinct naturally, however, human activity has sped up the rate of decline. Scientists now estimate that ten thousand times more species are being lost than the normal natural rate, because of humans. 

Shrinking forests, urbanisation, population growth and economic activity have affected animals and insects, with global insect populations estimated to have declined by 40%, by 2022, and global animal populations shrinking by 70% over the last 50 years.

Primates, big cats, marine mammals, reptiles, birds and bees are all experiencing significant declines.

Species Decline Facts

  • 85% of primate species are in severe population decline, with two-thirds of species classified as endangered.
  • All big cat species are expected to be lost within 10 to 15 years. This is largely because of poaching for their fur and body parts.
  • Every year, 650,000 marine mammals (such as seals, whales and dolphins) are accidentally injured or killed by fishing equipment.
  • Lizards are very vulnerable to climate change; if the current patterns of change continue, 20% of all lizard species are predicted to be extinct by 2080. 
  • 20% of all bird species in Europe are threatened by extinction. 
  • 25% of all bee species became rare or extinct between 2006 – 2015.

Food Production

Agriculture as a whole is responsible for a substantial proportion of greenhouse gas emissions in the UK (10%). Only a tenth of this is carbon dioxide, with the majority being methane (50%) and nitrous oxide (40%). 

Meat Production

Globally, the meat and dairy industry accounts for about 15% of greenhouse gas emissions. The majority of that is generated through the production of beef. 

Around 15,000 litres of water and 3kg of grain are needed to produce 1kg of beef. A litre of cow’s milk requires about 500 litres of water. Cattle farming is also the leading cause of deforestation in some parts of the world. 

Significantly less water is used to produce plant-based protein (pulses need 4,055 litres per kilogram). However, the production of a gram of nut protein requires more water (139 litres) than the production of a gram of beef protein (112 litres). 

In 2018, 30 million acres of tropical rainforest were cut down for animal agriculture, which is equivalent to 43 football fields every minute for a whole year. Intensive grazing of land can lead to soil degradation and erosion. Soil is a large carbon store – as it is damaged, it releases CO² into the atmosphere. 

Crop Production 

Approximately 75% of all crops, including fruits, nuts and berries depend on pollinators. A decline in pollinator species could cause food shortages for humans and animals, as well as removing important habitats for small mammals and insects.

One third (33%) of food production relies on bees. Species such as carpenter bees, bumblebees, mining bees, mason bees and Cape bees pollinate wild plants and crops around the globe. The global crop production pollinated by bees is estimated to be valued at £460 billion.

There you have it, Human Impacts on Species and Ecosystems revision laid bare. You can find more GCSE Geography revision here!

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