Cork's Lough - Biodiversity Made Local

There's no doubt that the recent humpback whale activity off the southeast coast has been a real treat for nature lovers. The spectacular still images captured by Patrick Whooley and others serve to whet our appetites for the high definition video footage promised for later in the Spring.

However, when such grand natural displays are visible so close to us, there is a tendency to overlook what is right under our nose when it comes to the natural world.

That's why a new publication on the biodiversity of Cork City is so timely. Nature in the City was produced by Cork City Council as a product of the Cork City Biodiversity Plan 2009-2014 and makes for interesting reading.

It's also a timely publication, coming as it does, at the start of 2010: the International Year of Biodiversity. The UN have designated it a "celebration of life on earth and of the value of biodiversity for our lives".

Biological diversity (or biodiversity for short) is basically the variety of organisms within a given space or ecosystem. So we can talk of biodiversity at the global level or at the local level (e.g Cork City). As well as the obvious measures of biodiversity such as the numbers and varieties of plants and animals in an ecosystem, biodiversity also includes the wealth of genetic differences within those species.

The UN estimates that about 1.75 million species of living things have been identified. However, it's reckoned that there are about 13 million species in total on the planet and less conservative estimates put that figure closer to 100 million. This means that every habitat destroyed and every river polluted could mean that we are loosing species that we don't even know about yet.

Biodiversity also encompasses the variety of ecosystems such as those that we find in deserts or woodlands, mountains or rivers. By protecting these ecosystems, we protect the variety of species that make their homes there.

Not just that though, protecting biodiversity also brings real benefits for humans; often economic benefits. For example, the Great Barrier Reef in Australia is estimated to contribute 6 billion Australian Dollars to that country's economy based on tourism, recreational activities and commercial fishing.

Closer to home, in the UK, a 2003 report estimated that forests contributed £1 billion to the economy. That includes the economic benefit derived from recreation (£393 m), biodiversity (£386 m), landscape (£150 m) and the forests ability to sequester or tie-up carbon (£94 m). The UK forestry study didn't even include the benefits of supplying fresh, clean drinking water, the cleansing of pollutants from the air and the reduction of soil erosion.

In Nature in the City, our attention is drawn to some of the important sites of biodiversity importance within the Cork City. For instance, the Lough is a familiar site to all Corkonians and its biodiversity (although we may not call it that) is a source of great pride and affection for many of us.

This shallow, spring-fed lake has at its centre a densely wooded island which acts as a refuge, roosting and breeding site for a variety of resident bird species including Mute Swan, Shoveler Ducks, Tufted Duck, Pochard and Mallard. Large numbers of Gulls, Starlings, Little Egrets (and even the odd Cattle Egret), Jackdaws and Magpies also utilise this important site.

The publication notes that up until the 1950's a range of aquatic plant species covered 90% of the Lough's surface until the introduction of Carp in 1954 for fishing purposes led to the disappearance of most of this vegetation within 10 years. The Carp are voracious herbivores which thrive on the amount of vegetation that remains. In fact, the Irish record of 29 lb 14 oz was caught at the Lough in 1988.

Unfortunately, as the approximately 2,000 Carp flourish, the health of the Lough itself and the rest of its inhabitants hasn't been maintained. In recent years, water quality at the Lough has declined significantly. This has lead to the growth of toxic microorganisms such as Clostridium botulinum which has been the cause of a number of catastrophic poisonings resulting in the death of large numbers of swans and ducks. The most recent, in July of 2009, resulted in the loss of 50 swans.

The cause seems to be two-fold. The lack of aquatic vegetation caused by the high Carp numbers leads to low levels of oxygen in the water body. Add to that the high levels of bird droppings from birds attracted by the large amount of free food delivered by well-meaning locals and the abundance of waste bread means that algae and bacteria flourish thus further reducing water quality.

At the moment, augmented by the harsh winter, the Lough seems a shadow of its former self. Swan numbers are dramatically down and while there is no doubt that the Lough was over-populated, it is hard to see such a defining symbol of Cork at such a love ebb. If ever an example were needed of the importance of biodiversity at a local level, Cork's low-affair with the Lough and it's determination to save it is surely such an example.

Nature in the City a guide to Biodiversity in Cork City is published by Cork City Council with the support of the Heritage Council. The publication is available free of charge but in limited numbers from Cork City Council's Heritage Officer at heritage@corkcity.ie or Tel 021 4924757