What is biodiversity?
Biodiversity refers to the incredible variety of life that exists on our planet, and it exists at many different levels. There is a diversity of species, with about 1.5 million species currently known to exist, although scientists estimate that there are millions more that have yet to be discovered. There is also diversity within species, with different populations of the same species having different appearances, behaviours, and genes. Even within populations of the same species, there is diversity, with different individuals having different genes and different behaviours. These diverse forms of life don’t exist in isolation, they all exist together, and work together in an ecosystem.
However, when the term biodiversity is used it is often just referring to species richness, which is a measure of how many species exist in an area. Whilst not the only import factor in biodiversity, it is a good way of measuring it and is also more easy and practical to measure than other factors.
Why is biodiversity important?
In short, biodiversity allows us to survive. All essential ecosystem services (which are ecological processes that benefit humans) rely on biodiversity. These ecosystem services include things such as cleaning water, absorption of certain chemicals which would be harmful if they built up, and the production of oxygen among many others.
Biodiversity is also important in the food production process. Many of the food crops humans grow require animals to pollinate them, and biodiversity is important here as a diverse range of pollinators are needed for optimal crop growing conditions. Without this biodiversity providing this service, growing crops would be much more difficult, and in some cases, even impossible.
Biodiversity is also important in allowing ecosystems to cope with change. This is because if an ecosystem has lots of biodiversity, and a change occurs in that ecosystem, then it is much more likely that a species or population of a species will have the necessary genes or behaviours to survive that change, whereas if the ecosystem has little biodiversity it is possible that all the species or populations in that ecosystem could be wiped out. This is of course an important issue considering our current climate change situation and other environmental pressures, where many ecosystems are experiencing changing conditions and are likely to continue doing so.
Biodiversity is also important just because of its value to humans. We enjoy being in nature and seeing biodiversity, it brings us joy and improves our mood and mental well-being. In this way, it is easy to see how a wide diversity in nature also represents a vital part of our lives.
Genetic diversity and functional diversity
Genetic diversity can refer to both diversity of species and diversity within species. It basically just means the diversity of genes. Genetic diversity of course exists between species because different species have totally different genes. It also exists within species.
Genetic diversity within species refers to the diversity of alleles (which are different versions of the same gene). For example, the eye colour gene has different alleles that produce different eye colours. A species’ genetic diversity is greater when there is a greater number of alleles, and this constantly changes. The alleles present, and the number of individuals with each allele varies over time, and alleles can disappear from a population and new alleles can appear.
Having a large variety of alleles is beneficial and makes a species more likely to survive. This is because if the conditions the species lives in change, then the more alleles there are, the more likely it is that one of those alleles will allow the individuals with that allele to survive in the new conditions.
Functional diversity refers to the fact that some species are more differentiated from each other than others. For example, two different areas could both have four species living within them, with one having four different species of seed-eating bird, and the other having one species of seed-eating bird, one species of insect-eating bird, one bird of prey species, and one species of mammal. In this scenario, both areas would have the same species richness, but the second area would be much more functionally diverse than the first.
This is because each species plays a particular role in the ecosystem, and some species play a very similar role to each other, whereas some species play very different roles to each other. This means that having an extra species present, that plays a similar role, doesn’t increase the functional diversity very much, as there are still the same roles being fulfilled. But having an extra species that fulfils a different role does increase the functional diversity because there is now a new role being fulfilled in the ecosystem.
It is important to take functional diversity into account when thinking about biodiversity because species diversity and functional diversity can vary quite a lot. This means that if functional diversity is ignored, it is possible to overestimate the diversity of an area.
How bad is biodiversity loss?
What are the big problems facing nature?
All around the world, biodiversity is currently declining with many different human activities contributing to this loss. Out of all the land on the planet, three quarters has been significantly altered from its natural state, and out of all of the ocean areas, two thirds have been significantly altered in some way. That means that in all these areas, biodiversity levels have been adversely affected.
Agriculture is one of the main culprits of land alteration. Over one third of the Earth’s land is currently used for either growing crops or raising livestock, and around three quarters of the world’s freshwater supplies are used for these purposes. This has a massive impact on biodiversity in these areas, as the natural environment is destroyed and replaced with a monoculture of crops, or with one species of animal. This effectively reduces the biodiversity to almost nothing. Biodiversity in surrounding areas is also affected by the reduced freshwater supplies available, due to the diversion for use by farming.
Habitat fragmentation is another factor that behind increasing biodiversity loss. Habitat fragmentation refers to the process of the few natural areas that are left untouched becoming isolated from each other. This makes it difficult for wildlife to travel between them, which they often need to do when searching for habitats or food. This causes a reduction in biodiversity as it can cause some species to become extinct in certain areas, or even completely, due to increased difficulty in survival.
Another problem that is driving biodiversity loss is that of invasive species. These are species that, due to human activities, have been moved to areas outside of their native range and have subsequently managed to thrive in these new areas. Despite the invasive species thriving, the local species tend to suffer, and their numbers decline or they even become extinct as a detrimental effect of the new, alien presence in their habitat or local area. This is because the invasive species can predate local species that have not evolved defences to this new predator, or can outcompete them if they both require the same resources such as food or habitats. Beyond this, invasive species can also spread new diseases to local species which have not developed an immunity to them.
Overfishing is another commonly cited problem which has a serious effect upon biodiversity. Our oceans are being increasingly fished, and this is causing a massive reduction in stocks, both the target species of fish and also any other species that get caught as bycatch. This is having a devastating effect on the biodiversity of our oceans, as huge numbers of fish are being removed from the ecosystem on a daily basis. This is causing a massive decline in marine biodiversity.
And of course, climate change is also another factor that has a major effect on biodiversity loss. Climate change is causing ecosystems to change, and this is causing many different species to decline in number or to become extinct entirely. Also, in areas where the other factors are present, such as farmland or areas with invasive species problems, climate change is occurring alongside these other factors, exacerbating problems and adding an extra layer of threat to biodiversity.
Over the last hundred years or so, humanity has come to dominate planet Earth, massively altering natural landscapes and ecosystems and simultaneously causing rapid changes in the natural environment. This has caused a severe decrease in biodiversity and has caused many scientists to declare that we are now living in a new geological epoch, called the Anthropocene. It is now expected that millions of years in the future, it will be possible to see the effect we are currently having on biodiversity within the fossil record.
What’s the prognosis for the ongoing survival and overall health of animals and insects?
It is a known fact that species go extinct as a normal part of life. Throughout the entire history of life on Earth, vast numbers of previously existing species have gone extinct. In fact, over 99% of all species that have ever existed are now extinct. However, species extinction usually happens at a slow rate, and the species that become extinct are replaced by other species. The exception to this has been during the Earth’s five mass extinction events, during which the rate of species extinction was massively sped up, and a huge proportion of the species in existence at the time went extinct extremely quickly – by natural standards.
Many scientists say that we are now undergoing a sixth mass extinction event because the rate of species extinction is so high. This sixth mass extinction is caused entirely by human activity, and we don’t know exactly how it will play out compared to the previous five which were caused by natural processes. However, after the previous mass extinction events, it took millions of years for life on Earth to return to a state of ‘normal’ balance.
Of all the species that have been assessed by the IUCN, a worryingly high 28% of them are listed as threatened with extinction. This is obviously having a severe effect on biodiversity. And unless action is taken to stop it, even more species will decline and become threatened. It is thought that a 20% decrease in biodiversity is a threshold beyond which ecosystem services will be compromised. It is also thought that over a quarter of the Earth has already exceeded this threshold, with many more areas in danger of exceeding it if current trends continue.
In general, the prognosis is better for species that are able to live anywhere in a large area of land, compared to species which are only able to survive in a very specific habitat which may be found only within a small area of land. This is because the species which can only live in smaller areas are much more vulnerable to anything that disturbs their habitat, as they have nowhere else to go. This means that if that small patch of land is turned into farmland, or a town or city is built there, then it is likely the species will simply become extinct.
What can be done to stop biodiversity loss?
What conservation and legislative initiatives are there?
One important way to help prevent biodiversity loss is to promote the sustainable intensification of agriculture. This can help to lessen the impact that agricultural intensification has on biodiversity loss. However, it can be difficult to do this without there being drawbacks to the farmers, which means in many instances they may well be reluctant to implement these changes. Therefore, it is important to do this in a way that benefits the farmers as well as the biodiversity such measures would look to promote and protect. For example, realising increased biodiversity can benefit agricultural productivity by contributing to things such as pollination, soil fertility, and pest control making it a mutually beneficial exercise if delivered appropriately.
Subsidies can also be used to help mitigate and reduce biodiversity loss. This can be done by only providing subsidies to agricultural processes that don’t have an unsustainably negative impact on biodiversity. This will encourage farmers to focus on these activities and to use less of their land for activities which tend to have a larger negative impact on biodiversity.
Dealing with invasive species is also another important way that biodiversity loss can be prevented. Doing this in the early stages is by far the easiest and most cost-effective way to achieve this, before the invasive species in question has become fully established in the new environment and too difficult to remove. Therefore, the best way to deal with this issue is to take swift action when it seems there’s even a possibility of a species becoming invasive. This way, the action will be more effective at halting biodiversity loss before it starts – prevention is always better than cure. This kind of approach will typically be much cheaper as a result of swift action, meaning that authorities will be more willing to undertake the necessary steps to help remedy a potentially serious situation before it takes hold.
What can individuals do?
There are also things that we as individuals can do. For example, we can help increase biodiversity in our gardens. We can do this by making our gardens diverse environments for wildlife, with lots of different plants that will provide food and habitats to a wide range of different species. And of course, we can refrain from using any kind of pesticides or herbicides in our gardens wherever possible. By making our gardens into attractive havens for promoting biodiversity, we can help to counteract the pressures and negative effects on biodiversity that increased urbanisation has had on the areas we live in.
Another thing we can do is to reduce our contribution to climate change. Climate change has a significantly negative effect on overall biodiversity around the planet. With this in mind, whatever we can do to help slow down, and ultimately halt the progress of a changing climate, then we are ultimately helping to prevent further biodiversity loss. This means that when we make environmentally friendly and carbon conscious choices, we are also making biodiversity friendly choices.
To further help reduce biodiversity loss a powerful action we can take as individuals is to avoid products that were grown with the use of pesticides or using unsustainable, intensive practices. Pesticides have a negative effect on biodiversity as they kill many species, not just the target species identified by the grower as a pest. This means that when pesticides are used there is often a significant decrease in biodiversity in that area, and when pesticides are used over large areas of land, this can in turn have devastating consequences for local biodiversity. By not contributing to this practice, we can help to reduce the demand of pesticides and subsequently reduce their usage, alleviating the pressure placed on biodiversity as a result.
Finally, we all know that a little knowledge can go a long way and with this in mind, reducing the scale and speed of biodiversity loss is always helped by staying informed and helping to educate other people about the full extent of the problem at hand, the consequences that biodiversity loss will lead to, and the ways that we can all help to stop it. People can’t help to reduce biodiversity loss if they don’t know the best and most impactful steps to take on an individual level, and beyond this, many of us won’t do those things if we don’t know why it’s important that we need to in the first place.