Background on Biodiversity
We’re losing the natural world at the fastest rate ever recorded in human history. Global biodiversity loss is estimated at between 100 to 10,000 times the average background extinction rate. Since 1970 there has been an estimated 68% decrease in mammals, birds, reptiles, amphibians and fish globally. Currently, up to 1 million species of wildlife face extinction in the coming decades.
While biodiversity loss is nothing new, it is the extreme rate that it is currently happening at which is so catastrophic for the world’s ecosystems. The science shows that human activities are the driving force behind it with a recent study showing that just 3% of the world’s land remains ecologically untouched by humans.
Predominant factors behind biodiversity loss
The predominant factors are:
- Habitat loss and degradation: this includes destruction, fragmentation and/or alteration of natural habitats for species through means as deforestation, conversion for agriculture, resource depletion. This has the effect of destroying food resources and living space for species resulting in their extinction.
- Invasive species: this is the introduction of new species, either accidentally or purposefully, which upset the natural balance of the ecosystem and drive out existing species. A well-known example is the grey squirrel in the UK.
- Overexploitation: when an animal is over hunted or harvested it can deplete its populations before it has a chance to bounce back. This happens both on land and in our oceans with overfishing of cod being a prime example with the species having undergone a dramatic decline in the UK.
- Pollution: As humans pollute environments it creates damaging, and sometimes fatal conditions for species causing dramatic declines in populations. This can be caused by a range of issues including air pollution, chemical spills or dumping, and nutrient loading from agriculture.
- Climate change: As our climate changes from greenhouse gas emissions, this drastically changes the worlds ecosystems and the habitats of species. Changes to temperature and rainfall will cause changes to available food sources, tolerable conditions, mating patterns and more.
It’s important to understand that these five drivers are not separate from one another in the same way that biodiversity isn’t a separate issue to climate change and other environmental issues. Our climate, ecosystems and environments are complicated and connected systems which all impact on one another.
A loss of biodiversity and well-functioning ecosystems has the potential to cause significant damage to the planet and to our way of life. These systems and populations are critical for providing food, energy and maintaining water and soil quality. Biodiversity also acts as a positive feedback mechanism for regulating the earth’s climate and mitigating climate change. Alongside all these practical necessities, nature provides us with recuperation, recreation, and inspiration.
Biodiversity in the UK
In the UK we’ve seen significant decreases in biodiversity levels and the country is considered one of the most nature depleted in the world, with 15% of species facing extinction. Since 1970, 41% of all UK species have declined. Of the G7 countries, the UK has the lowest remaining levels of biodiversity and failed to meet 14 of the 19 Aichi biodiversity targets which it committed to meet by 2020.
Habitat loss and degradation have had the largest impact on biodiversity. This is due to vast areas of land being converted for agricultural use, leaving it in a degraded state to support wildlife, and pushing wildlife out of suitable areas. Other factors include climate change, urbanisation, pollution, hydrological change and invasive species.