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Protecting Ireland’s Oligotrophic Lakes

Updated: Oct 13, 2021

Emma Gray, Heather Lally and Giovanni Cappelli of the Marine and Freshwater Research Centre, Galway-Mayo Institute of Technology, on their peatland project examining the flora and fauna within protected freshwater lake habitats in blanket bogs in the west of Ireland.

Small blue lakes set in brown bog with hills & sky in background
Figure 1: Oligotrophic lakes in the Owenduff Nephin Special Area for Conservation (Pic: Heather Lally)

Peatland ecosystems contain many freshwater lake habitats, which harbour a suite of specialist plants and animals important for biodiversity. Two freshwater lake habitats found in blanket bogs along the west of Ireland are protected under the European Union Habitats Directive as ‘Oligotrophic waters containing very few minerals of sandy plains (Littorelletalia uniflorae)’ (3110 lake habitats) and ‘Natural dystrophic lakes and ponds’ (3160 lake habitats). Ireland is a stronghold for both habitats within Europe due to our extensive areas of blanket bog, but unfortunately the conservation status of 3110 and 3160 lake habitats are bad and inadequate, respectively.

Currently, the composition of macrophyte communities (see figure 2, below) are used to characterise these lake habitats, but in reality, these lakes host a wide range of ecological elements which are poorly described. Therefore, the aims of the EPA funded PeAT Lakes project are to determine whether 3110 and 3160 lake habitats can also be characterised using macroinvertebrate, zooplankton and algal communities and examine relationships between these biota and their water chemistry. By doing this we aim to evaluate the environmental conditions necessary and thus propose monitoring methods and assessment tools that will maintain these protected lake habitats in a favourable conservation status.

Figure 2. Examples of macrophytes found in these lakes and pools - above & below. (Photo credit: Giovanni Cappelli)

We are currently monitoring 24 lakes clustered in the Owenduff/Nephin (Co Mayo) and Connemara Bog Complex (Co Galway) Special Areas of Conservation (SACs), where monthly sampling of various water chemistry parameters is conducted along with two biological surveys, one in spring and summer respectively. So far, we have found that these lake habitats are oligotrophic in nature and contain a rich diversity of algae (Figure 3), zooplankton (Figure 4) and macroinvertebrates (Figure 5).

Figure 3. Desmids (algae) commonly found within these lake types (Pic: Emma Gray).

Figure 4. Zooplankton live in the water column and are abundant within these lake types (Photo credit: Sadhbh Mahony).

Figure 5. Examples of damselfly larva and an emerging adult along with a water beetle (Dytiscidae) which are commonly found in these habitats. (Photo credit: Giovanni Cappelli)

The team are currently working through the identification of these biological samples and you can keep up to date with our findings by checking our PeATLakes website or by following us on Twitter @PeAT_Lakes.


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