DEA member Dr Marion Carey in the Crikey Health Blog

The following excerpt by Marion Carey appeared in a Crikey article and appears here under a Creative Commons licence.

As the Earth approaches a critical tipping point, a reminder about why our biological wealth is critical for health……

Self interest: a sound reason for protecting our biological life support systems

It was World Biodiversity Day last month.

But how many of us will gave it a thought? How many of us understand what biodiversity means? Why should we care?

Biodiversity is the number, variety and variability of living organisms on the planet. There is genetic, species, and ecosystem diversity. Ecosystems comprise communities of plants, animals and microorganisms, and their interactions with one another and the physical environment.

Australia has about ten precent of the world’s biodiversity, with a unique evolutionary history. More than 80 per cent of the country’s flowering plants, mammals, reptiles and frogs are unique to Australia, along with most of its freshwater fish and almost half of its birds.

Yet the record of extinctions in Australia has not been a proud one, and we have a long list of critically endangered species.

The last Christmas Island pipistrelle, a tiny Australian bat, recently became extinct but would most people in the hustle and bustle of their daily lives see that as important?

Tim Flannery has written about this “unmourned death of a sole survivor”. Flannery argues that we should care about these animals as a values issue in the same way we should care about the human rights of others we don’t know.

Personally I don’t hold much hope for this argument, despite its appeal. I think we should care, and be taught to care out of self-interest – the self-interest of own survival, health and well-being.

We spend so much time caring about our financial wealth – we are fixated on it. Yet biodiversity represents our biological wealth. It provides a wide variety of life supporting ecosystem services upon which we depend for our health, economy and survival.

We have long been relying on the resilience of these natural systems to support us, but we have now severely depleted them, leaving us with a much more uncertain future.

Biodiversity is an insurance policy for our ecosystems, providing stability and resilience with the ability to adapt in the face of changing environmental conditions.

It underpins ecosystem services to humans including food production, soil fertility, waste decomposition, nutrient cycling, seed dispersal, pest control, pollination, medicinal and genetic resources, climate regulation, natural hazard protection, water purification and cycling, disease regulation and psychological well-being – to name just a few.

The reality, as described eloquently by some eminent Harvard physicians, is that “human beings are an integral, inseparable part of the natural world, and that our health depends ultimately on the health of its species and on the natural functioning of its ecosystems”.

Let’s take a couple of examples – food and water security and mental health.

Natural vegetation regulates the hydrological cycle and is very important for fresh water quality and quantity. As water flows over the land, trees hold the soil, retain nutrients, prevent erosion and allow water to seep more slowly into the earth and the release back into the atmosphere is controlled through transpiration. Forests can affect local microclimate and can increase local water supply.

Water filtration and purification is especially important for the prevention of waterborne disease in humans. Loss of biodiversity around waterways leads to loading of waterways with pathogens and nutrients. This may lead to contaminated drinking water, or blooms of harmful blue-green algae which produce a range of toxins, making water unfit for human use.

Estimates of the financial worth of such services of the Catskills mountain forest catchment for New York City, for example, have been valued in billions of dollars.

The 157,000 hectares of forest that protect Melbourne’s water supply have been called “a priceless legacy”, ensuring some of the best drinking water in the world. In the absence of such systems, more extensive and expensive artificial treatment facilities would be required.

Biodiversity also supports food security and dietary health. Food productionrelies on genetic diversity, crop pollination, pest control, soil formation, fertility, and nutrient recycling.

Diets based on a diversity of food species promote good health.  In the space of a week at least 20 to 30 biologically distinct types of food are needed for good human nutrition.

While about half of childhood deaths in the developing world are due to under nutrition, in countries such as Australia, poor nutrition is linked tochronic disease with increases in hypertension, serum cholesterol, obesity and some cancers.

Many crops are dependent on specific natural pollinators for fertilisation yet bee populations in many countries have been decimated. In Australia, natural vegetation is important for both commercial and native bees, providing essential nectar and pollen.

Climate change is having severe impacts on ocean ecosystems – through both acidification and warming. This in association with other stressors will have significant impacts on fisheries, a major source of protein and other nutrients for the human diet.

An estimated 500 million people globally depend for their daily existence on coral reefs – marine species provide 17% of animal protein consumed by humans. Yet the predictions are that CO2  concentrations of 450ppm will largely eliminate carbonate coral reefs as we know them.

A large body of evidence is accruing on the health benefits of contact with natural environments.

These physical and psychological benefits include facilitation of exercise for cardiovascular health, improvement in concentration, benefits for children’s cognitive development and reductions in anxiety and depression.

Spending time in with nature is being increasingly promoted as an antidote to our stressful urbanised lifestyles: “Feel blue? Touch green!”

Perhaps it is our evolutionary wiring that makes us seek out connections with other living things, even beyond what is required for our basic needs, soothing our mind and spirit.

The popularity of gardening, bird watching, visiting zoos, snorkelling, diving, bushwalking, nature retreats, swimming with dolphins, whale watching, and so on, testifies to the value of natural species to human wellbeing.  In fact, the increasing isolation of children from the natural world has been coined “nature-deficit disorder” and sparked community movements to reconnect people with nature at an early age.

So let’s spare a moment to consider biodiversity, and how (whether we want to admit it or not) we are locked into the intricate web of life on this planet, dependent on other species.  Let’s protect our biological life support for our own sake.

Read the full article.

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