Health and biodiversity

by Dr Elizabeth Cullen.

Swallows, dandelions, hawthorn hedges and spiders …. and the many species of life with whom we share the planet – this is our biodiversity. The familiarity of our countryside, seashore and woods belie their profound importance to our health and well-being.

All our food derives from our biodiversity, with one in three mouthfuls of food resulting from the pollination activity of bees[1] . Soil fertility depends on micro- organisms breaking down nourishing organic matter. We are warmed by the heat of trees that grew millions of years ago and we use wood every day. Wetlands and forest canopies reduce the levels of pollutants in our water and air and our bogs trap carbon. Sand dunes and estuaries act as buffer to floods and severe weather events. Our psychological and spiritual well being is enhanced by the joy and private moments of wonder in contemplation of the natural world.

We can learn more about the physiology of illnesses such as diabetes, renal failure and osteoporosis from the natural world. If humans hibernated like bears, neither eating, drinking, or exercising for almost half a year, they would probably develop these conditions. Yet bears remain alert and reactive during hibernation with female bears even giving birth and nursing their off-spring. Our health already benefits from penicillin and the aminoglycosides, which originate from bacteria, while the cephalosporins originate from a fungus. Paclitaxel was obtained from the yew tree, through the random screening of 35,000 plant samples. New pharmacological agents for epilepsy and ischaemia may result from cone snails, although to date, just 100 of their estimated 50,000 chemicals have been studied[2] .

Irish biodiversity

Irish biodiversity is brimming with wonder; the whirligig beetle speeds about every day on the surface of Irish ponds, its eyes both on and under its head, well suited to surveying predators in the sky and under the water; the intricate underwater architecture of the home of the caddis fly larva is a wonder to witness…In the words of Professor John Feehan “There is more to amaze, more to wonder us, more to bring us to our knees, in the lives of wild things, in ponds, bogs and woodlands than our short lifetime can ever encompass”[3] . From algae to eagles, there are now over 31,000 species in Ireland, with over 2,000 vascular plants, over 500 species of marine and 29 freshwater fish, 25 terrestrial mammals, 457 bird species and over 11,000 species of insects.

Decline in Irish biodiversity

Notwithstanding the astounding diversity of life on earth, an unprecedented mass extinction of life is occurring Over a fifth of all known mammals, and almost three quarters of plants are under threat with between 150 and 200 species becoming extinct every day[4] . In Sichuan province, following the decimation of bees by pesticides, villagers now pollinate the pear trees by hand with paintbrushes[5].

In the past 30 years, Ireland’s biodiversity has also declined rapidly with many unique species now in need of protection. There are many disturbing facts; eighteen percent of the native Irish butterfly fauna is under threat of extinction and one species, the Mountain Ringlet is extinct[6] . The status of half of the bird species is of concern because of small or declining numbers[7] ; in particular, several of the 25 Irish bird species on the Red list, are believed to be on the brink of extinction. The corncrake used to be heard in every county in Ireland; now, the population of calling birds is down to less than 140. A recovery plan is now in place but its future is still’ on a knife edge’[8] . The numbers of curlew have fallen from 12,000 to 1,700 in 14 years and are now described as being in ‘freefall’[9] , and risk extinction in only 10 years[10] . The decline in insect numbers has led to both swallows and starlings being on the Amber list of conservation concern. The cornbunting is extinct.

A third of our slugs and snails are on the verge of extinction. The freshwater pearl mussel, our longest living animal species is in critical decline. Ireland is one of the last places in Europe where this little creature survives, yet most of our living pearl mussels were born before Irish independence[12] . Bees are Ireland’s most important pollinators, yet of the 101 different species of bee that occur in Ireland, approximately 30 are threatened with extinction and three have become extinct over the last 80 years. There are seven species of plants that require immediate intervention if we are to save them from extinction.

At present, 11 species of birds, over 150 species of flowering plants, 1 amphibian, 6 fish, and 1 mammal classified in Ireland as either endangered, vulnerable or rare. The corncockle flower is now extinct. The single greatest reason in Ireland for the loss of our animals and plants is pressure on habitats, reducing the opportunity for organisms to access food and to breed. The intensification of agriculture and predominantly exotic conifer afforestation have placed substantial pressure on habitats and species. Competent inventories, showing the position of legally protected species are not available to most local authority planners[13] and housing developments, road building, the mowing of roadside verges, and the expanding numbers of golf courses have also contributed. Ireland has the lowest percentage of land area given to protected habitats in the EU. These pressures have resulted in less than a fifth of Ireland’s original peatlands being in a relatively intact condition and only 1% of the raised bogs in the midlands remain. The first assessment of the conservation status of all 59 Irish habitats and 100 protected species was completely unacceptable; over 90% of our habitats were classified as being either inadequate (46%) or bad (47%). The raised bogs, hay meadows, unspoiled sand dunes, and wetlands have slipped silently away from us…

Invasive species harm ecosystems by consuming food used by native species, carry new pathogens, or are toxic. There are 59 plants in the National Invasive Species Database, including the Japanese knotweed, which spreads relentlessly, overwhelming other plants and the Water Fern, which is a significant threat to water quality. There are also 27 animals in the database such as the Zebra mussel which consumes the food of other species and the New Zealand flatworm, which predates on earthworms.

Pesticides, industrial chemicals and synthetic steroids alter the balance of chemicals in living organisms, and have been implicated in the thinning of eggshells, and the development of male and female sex tissue in single sex individuals. Recent work has detected evidence of adverse impacts of toxic chemicals on wildlife in the Shannon and in the river Liffey. Both cod and sole are overfished in the Irish Sea and cod stocks have virtually collapsed with little signs of recovery.

Mean annual temperatures in Ireland have risen by 0.7oC over the past century[14] . This rate of change will make it difficult if not impossible for many species to adapt. Climate change will put a fifth of Ireland’s native plants on the danger list, including weasels’ snout and Irish lady’s tresses[15] .

It will also impact on delicate relationships; for example, while caterpillars will appear earlier alongside the earlier appearance of oak leaves, the migrant birds that feed on these caterpillars will not arrive early enough.

Our role

Our way of life must enhance our life giving and life affirming biodiversity, not undermine it. Although statutory authorities have a responsibility to protect our biodiversity, or sustainable development as it is sometimes called, “It is individual choices, made billions of times a day, that count the most “[16] . In this light, the most important contribution we can make to the well being of our biodiversity is to firstly, reduce our consumption of the earth’s resources. Almost a third of Irish people do not use a significant proportion of their weekly food shop and the average Irish household throws out about 1.2 tonnes of rubbish per year. We need to recognize when we have enough. The concept of ‘enough’ has been comprehensively discussed by Anne Ryan; ‘Enough’ puts us back in touch with the part of us that understands beauty and scale and that empathizes us with the rest of creation’[17] . Reusing, recycling and buying locally will reduce our demands on the habitats of our fellow creatures. Growing our own food where possible and purchasing goods that are produced locally will minimize our impact on the earth’s resources.

We are richer when we know our neighbours – human, animal and plant…..when we know the names of the nearest trees to where we live, the most common birds locally, and where the nicest blackberries grow. The first sighting of a swallow or the first hawthorn blossom could be included in mainstream news. We can also choose to leave part of our garden free for wildlife, and can join organizations such as the Irish Wildlife Trust.

Exposure to biodiversity has been linked with reduced stress, increased physical fitness and increased social cohesion. When we were building a motorway, concerns about the impact that this might have on a small snail were ridiculed. Perhaps now is the time to ask where exactly our motorways and other signs of progress are headed.


1. United States Department of Agriculture Agricultural Research Service Website Accessed 13/7/2011
2. Chivian E and Bernstein AS. Embedded in nature: human health and biodiversity. Env Health Persp. 2004 112 (1) A12-A13
3. Feehan J. The Singing Hear of the World. Dublin: Columba Press; 2010
4. United Nations Yearbook 2010 Website accessed 13/7/2011
5. Girling R. Plight of the humble bee. Sunday Times Magazine. London: Sunday Times; 1-2-2009
6. Regan E.C, Nelson B, Aldwell B, Bertrand C, Bond K., Harding J. et al. Ireland Red List No. 4 – Butterflies. Dublin: National Parks and Wildlife Service, Department of the Environment, Heritage and Local Government; 2010
7. Robinson R.A. State of bird populations in Britain and Ireland In: Silent Summer. Editor. Maclean N Cambridge: Cambridge University Press; 2010 p.281-318
8. Deegan G. On the front line to save the corncrake. Dublin: Irish Times; 11-09-2010
9. O’Connell. P Iconic wader in trouble. Wings. 53 Birdwatch Ireland; Summer 2009
10. ‘ Native curlew at risk of extinction’ Eoin Burke-Kennedy Irish Times July 30th 2011
11. Photograph courtesy of Wildlife Extra
12. The Heritage Council Website Accessed 13/7/2011
13. Doogue D. A place for plants. Irish Wildlife. Irish Wildlife Trust; Spring 2011
14. Sweeney J, Albanito F, Brereton A, Caffarra A, Charlton R. Donnelly A, et al. Climate Change – Redefining the impacts for Ireland. Strive Report. Wexford: Environmental Protection Agency; 2008
15. Climate change puts fifth of Ireland’s native plants on danger list By David McKittrick, Independent 14-12-2007
16. Progress towards the European 2020 biodiversity target. Copenhagen: European Environment Agency; 2009
17. Ryan A. Enough Is Plenty: Public and Private Policies for the 21st Century. Dublin: O Books; 2009

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