Biodiversity and Human Health
March 18, 2012
Loss of biodiversity is occurring at the fastest rate since time began, and nearly all of this loss is due to human interaction with the environment. Whilst many may exclaim that it is sad to see some of our favourite species go, there are a number of deeper reasons to be concerned by this loss. One of these is that human well-being is inextricably linked to biodiversity, particularly as we rely on a number of different plant and animal species for ecosystem services including food provisions, social services, security and health. A loss in biodiversity can often lead to some areas being plunged into poverty, and may impact the future availability of plant and animal products for medicines, clothing and development. Humans are also particularly sensitive to their environment, meaning that a loss of natural environments may lead to negative psycho-social effects.
The Loss of Biodiversity – A Very Real Problem
The loss of biodiversity is occurring at a rapid rate due to ‘human domination of the Earth’s ecosystems’. Humans have had a greater effect on the global environment than any other species, and this seems unlikely to change in the near future. The human effects on biodiversity include, but are not limited to, habitat fragmentation and destruction, climate change, over-exploitation of fish, animal and plant resources, and introduced and invasive species. These are all directly caused by human populations (such over-exploitation of fish) or indirectly affected by human activity (such as secondary effects of climate change or disruptions to the nitrogen cycle). As human populations grow, the burden on habitats will increase, leading to more biodiversity losses and more changes in environments. As it stands, the rate of biodiversity loss varies between habitats and geographical areas but is currently estimated through the species-area model at being in the thousands per year. Figure 1 shows current biodiversity loss comparative to the past and recent past, as well as modelling the potential future biodiversity loss.
Figure 1 – Distant past, recent past and potential future extinction rates (Millennium Ecosystem Assessment, 2005)
Linking Biodiversity and Human Well-Being
Having established that massive losses of biodiversity are occurring, it may seem easy to question why the human race should be concerned. Many of the human causes of biodiversity loss are linked to progress; habitat destruction is a result of improved housing provisions, introduced species occur as a result of better transportation, and over-exploitation of species may mean increased food provisions. However, this is an over-simplification of the system. A slightly dated view linking biodiversity and human well-being places emphasis on how species may go extinct before we discover possible medicinal properties that may benefit mankind. A lack of biodiversity can also be directly linked to lower food production, particularly of wild hunted meat or natural crops, affecting human ability to survive and thus their well-being.
This view simplifies the problem by only addressing the direct tangible benefits humans derive from biodiversity, and does not incorporate elements of Gaia theory. Gaia theory essentially suggests that all organisms and their environments are integrated as part of a closed-system, and effects on one area can indirectly impact another. The Amazon rainforest, for example, is currently a major area of concern with respect to biodiversity and habitat loss, but it can be hard for those in the Western world to appreciate how this can impact on their own well-being. There are suggestions that this presents an excellent discussion of how loss of biodiversity in this area leads to atmospheric changes felt worldwide, as well as the direct implications for those living locally.
Biodiversity is also important in a number of other areas. Human populations, for example, rely on clean drinking water supplies that are inextricably linked to the habitats of which they are a part. A lack of drinking water can be a result of global climate change, water diversionary tactics, or simply a competition for resources, all of which are directly or indirectly impacted by a loss of biodiversity. Water is necessary for all organisms, and a lack of supply may further compound the problem. This is only one of the more complex examples of how biodiversity and human well-being are linked.
There are further complications to the problem. As previously mentioned, biodiversity loss can often be linked to progress. Europe, for example, is one of the most densely populated areas in the world, and is associated with agricultural, industrial and technological progress. Many areas of Western Europe are also amongst those with the highest amount of habitat loss and lowest biological diversity. There is an overlap between the areas of greatest poverty and the greatest biodiversity, which may seem to counteract the link between biodiversity and human well-being, particularly as economic success is often associated with increased welfare and health. The results of Europe’s technological history should, however, be generalized with extreme caution to other areas of the world, as many of the current biodiversity hotspots have a far higher species richness than Europe ever had. Gaia theory also helps to support the idea that we need to combat biodiversity loss in these areas whilst they remain relatively diverse, as this will benefit global populations.
The Psycho-Social Effects of Biodiversity
The effects of biodiversity on human well-being outlined above are very direct and tangible, reflecting human resource needs. Whilst these are important, there are additional ecosystem services that biodiversity provides the human race, which are grouped under the term psycho-social effects. These generally rely on the well-established theory that humans receive great psychological benefit from environmentally attractive (and generally more biologically diverse) areas, but also incorporate newer concepts such as ecotourism and increased interest in gardening. It has been shown that humans have a psychological and social preference for housing in environmentally attractive areas, meaning that there is some perceived or actual benefit of living in these areas. Social standing was also shown to increase by the perceived attractiveness (closely linked to higher biodiversity) of the chosen area.
Interestingly, it is not just existing areas of biodiversity that can benefit psychological well-being. Fuller et al found that the psychological benefits of urban green spaces increases with species richness, suggesting that there is an important role for restoring biologically diverse ecosystems rather than preserving surviving areas. One study found that the reverse was also true; that environmental degradation leads to lower levels of happiness.
The psycho-social effects of biodiversity are big business. As previously mentioned, most of Europe’s natural habitat and corresponding biodiversity has been destroyed, and Europeans are big consumers of eco-tourism. Eco-tourism is seen as an alternative to conventional commercial tourism, and involves trips to environmentally fragile areas as well as conservation projects. Eco-tourism provides a number of different psychological benefits. Firstly, it is associated with a general feeling of well-being induced by being in an area of natural beauty and experiencing different organisms, again reinforcing the theory that biodiversity impacts psychological well-being. Eco-tourism is also associated with a feeling of altruism, induced by reducing impact on fragile ecosystems and preserving endangered species. Aside from these benefits to human well-being, eco-tourists generally have a higher environmental understanding and concern for the natural environment, potentially preventing biodiversity loss itself.
The positive psycho-social effects of biodiversity can also be seen by the increasing interest in gardening and allotment use amongst those in the Western world. Gardening has been shown to increase psychological well-being, partly from a feeling of ‘getting back to nature’. Biodiversity also increases (or at least stays fairly static) with small-scale agricultural projects and use of more traditional farming methods that focus on lowering the human impact on the environment. Again, this illustrates a human need for biodiversity that goes beyond the more traditional view that biodiversity has a medicinal or consumptive purpose.
There are those that dismiss environmental concern, suggesting it is the domain only of hippies. However, I hope I have shown that there are a number of benefits to be gained from the environment beyond the medicinal, and we should look after what we’ve got.