The Gearagh – Cork’s Nature Reserve
The Gearagh is a nature reserve, located in an area of submerged glacial woodland, two kilometers southwest of Macroom, County Cork.
It is situated at the point where the River Lee descends from the mountains and spreads into an alluvial plain, and extends for five kilometers, bounded by the townlands of Toonsbridge, Illaunmore and Anahala. It is designated a wetland of international importance under the Ramsar Convention, and also enjoys international protection as an EU Special Area of Conservation of 558 ha. It is a nature reserve under the Irish Wildlife Act and the reservoir is a wildfowl sanctuary.
Why is it a nature reserve?
These rare forests, in which the riverbeds are overshadowed by the trees, harbours the biological diversity of a very particular ecosystem. Once it was a dense woodland of ancient oak trees and is considered to be the last surviving full oak alluvial forest in western Europe. There are very few such places left in the world, for example in Czech Republic and the Amazon rainforest. These formations are essential for the maintenance of water resources and their availability due to a range of factors provided by the presence of this vegetation.
The Gearagh hosts an interesting commensalism interaction of two species: the freshwater pearl mussel and the Atlantic salmon.
Unfortunately, the area was flooded in 1954 in order to build two hydroelectric dams in Carrigadrohid and Inniscarra, which provide electricity for the nearby city of Cork and the surrounding area. Many trees were suppressed and many local families were removed from their homes in the forest and relocated prior to the flooding of the valley. Approximately 60% of the woodland was lost, most of which was ancient oak forest, in situ since at least 1650.
With the removal of the vegetation, the soil remains exposed to the direct impact of precipitation, previously deadened by the foliage of the crowns, promoting the suspension of particles that are carried by the increase in surface runoff. This process promotes the transport of these sediments and minerals, altering the physicochemical characteristics of the soil and intensifying the action of erosion. The web of roots formed by botanical specimens from these areas plays the role of containing the soil, providing its stability, and allowing infiltration of rainwater into the layers below the ground. By avoiding erosive processes, the vegetation aids the loading of the groundwater reservoir. Furthermore, in the 1950s the estimated wild Atlantic salmon run on the River Lee was 15,000 and nowadays that figure is less than 500, whilst the freshwater pearl mussel is almost extinct.
The Current State of the Gearagh
What was once a thriving alluvial forest at the Gearagh, boasting a unique collection of healthy species, is now more like an environmental disaster. However, The Gearagh still boasts a rich and rare biodiversity, in a wide but shallow water enclosing a series of small islands separated by anastomosing, mostly flat river streams, with a diverse ecological system and wide variety of plants, birds and fish, including freshwater pearl mussel, Atlantic salmon, whooper swans, kingfishers and otters.
There has been a marked increase in flash flooding since the straightening and dredging of the Toon river channel and its embankment for both the reservoir and intensive agriculture further up the river. This has detrimental effects on the anastomosing structure of the Gearagh itself, forming a single channel from the ‘band of braided streams’.
The Gearagh’s history is a good example of the difficulties encountered when striking a balance between energy production and nature conservation. Many environmentalists strongly argue against the supposed feasibility of basin-wide development whilst simultaneously protecting critical habitats. Certainly, it is a case of lots of reflection about the co-existence of infrastructure development and nature conservation.
Written by Roberta Maini
O’Mahone, Eadin. The Lost Forest: An Gaoire. October 27, 2017, https://www.sourcetosea.ie/fromsourcetosea/2017/10/the-gearagh.html. Accessed 06 July 2021
White, James. “The Gearagh Woodland, Co Cork.” The Irish Naturalists’ Journal, vol. 21, no. 9, 1985, pp. 391–396. JSTOR, www.jstor.org/stable/25538897. Accessed 06 July 2021
NPWS. The Gearagh SAC (site code 108) Conservation objectives supporting document – Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation and Rivers with muddy banks with Chenopodion rubri p.p. and Bidention p.p. vegetation Version 1 August 2016, https://www.npws.ie/sites/default/files/publications/pdf/The%20Gearagh%20SAC%20(000108)%20Conservation%20objectives%20supporting%20document%20-%20[Version%201].pdf. Accessed 06 July 2021
McCathy, Barry. O`Mahony.Declan. River Runner’ Feature documentary on the River Lee, Ireland, https://www.youtube.com/watch?v=5eyNX6JEGN4&t=77s. Accessed 13 July 2021.