The river Mulkear, part of the Lower Shannon Special Area of Conservation (SAC) Natura 2000 site, is important for Atlantic salmon (Salmo salar), European otter (Lutra lutra), sea lamprey (Petromyzon marinus) and other lamprey species. The conservation status of the SAC has come under pressure due to prolonged mismanagement of both the river itself and its catchment. Since the 1850s, river modification has straightened the river channel and removed meanders, resulting in a uniform channel with high embankments unsuitable for juvenile salmon. The installation of a series of weirs impedes the upstream passage of sea lamprey, while many species are affected by the decline of the riparian areas of the river. Contributing to this decline has been the planting of exotic conifers and the spread of invasive plants, such as giant hogweed (Heracleum mantegazzianum), Japanese knotweed (Fallopia japonica) and Himalayan balsam (Impatiens glandulifera).
The aim of the IShannonSACLAEO project was the sustained enhancement of the Lower Shannon SAC and, in particular, increased populations of sea lamprey, Atlantic salmon and European otter through the restoration of degraded habitat in river reaches along the river Mulkear. The project also aimed to remove obstacles to the upstream passage of sea lamprey to open up most of the catchment for spawning and recruitment; to reverse the damage caused by invasive exotic plants, such as giant hogweed, Japanese knotweed, Himalayan balsam, and non-native conifers, in the river’s riparian zone; and to improve breeding and resting habitat, and food supply, for otters.
The IShannonSACLAEO project was delivered by Inland Fisheries Ireland in partnership with Limerick County Council and the Office of Public Works. It enhanced and extended habitat for Atlantic salmon, sea lamprey and European otter in the Mulkear catchment, and generally raised awareness and understanding of the issues affecting the Lower Shannon Natura 2000 network site (SAC) to facilitate better management.
A wide range of actions were conducted to enhance the river and riparian areas. The project installed 28 rubble mats in the Mulkear River, using over 5 000 tonnes of rock, to create diverse habitats and improve in-stream and riparian biodiversity. In total, in-stream measures, such as random boulders and stone weirs, enhanced the river for wildlife over 16 km, while 1.1 km of bank protection and re-profiling work was done. The project beneficiaries researched, designed, manufactured and successfully installed fish passes to help sea lamprey ascend major barriers on the river. The Ballyclogh Weir was partially removed to open up the entire River Mulkear catchment for migratory fish. Over 200 km of riparian habitat was treated to control non-native invasive plant species, such as giant hogweed, Japanese knotweed and Himalayan balsam, which negatively impact on native vegetation and river bank stability, and increase the sedimentation of fish spawning beds. The project team improved otter habitat and installing artificial holts. Working directly with local farmers, the project also addressed water quality concerns and installed alternative watering solutions away from rivers.
Atlantic salmon have benefited from the instream work, and the water flow complexity and diverse environments it has created. Electro-fishing surveys showed that sites, not previously used by salmon, attracted increasing numbers over a three year period; the average density of salmon fry in the newly-created rubble mats at the end of this period was 0.72 fry/m². Sea Lamprey benefitted from the modification of two weirs, which assisted their annual upstream migration for spawning. At the Annacotty weir, upwards of 95% of all ascents were achieved on the two sea lamprey passes; while at the Ballyclogh weir, the barrier removal opened up an additional 184 km of spawning habitat and also removed the main location for illegal fishing activity. The results for 2014 showed that sea lamprey redds increased more than three-fold (from 85 to 296 redds) in the space of a single year. European otter benefitted from the work to reinstate wildlife corridors to reconnect habitats, primarily through tree planting and creating scrub cover. The project's work to improve sea lamprey passage has benefitted otter by increasing the availability of food for them in the watershed, which should allow for a higher density of otters. The installation of 10 artificial otter holts was based on the results of the project’s annual rapid assessment survey work, and by the end of the project two of these holts were occupied by otter.
The project’s conservation actions, and awareness raising and educational work, provide wider benefits to biodiversity by highlighting the importance of habitat protection and enhancement in the Mulkear catchment. The project established the Mulkear Conservation Volunteers to undertake practical, river-based conservation activities. It established an Environmental Education Programme, which undertook 74 classroom visits and field trips to the river that engaged almost 2 000 children in total. The project produced a series of five best practice guides, for the practical sustainable management of river catchments in Ireland and a Management Plan for the Mulkear River. The project also established links with a range of conservation groups, national state and semi-state bodies, and other stakeholders.
The project has helped implement the conservation objectives of the Lower Shannon SAC and the Habitats Directive for Annex species. The project also indirectly assists the aims of the Water Framework Directive. The project required innovation on many fronts, as in many cases the river restoration procedures and methodologies were being carried out in Ireland for the first time; for example, the project developed an innovative sea lamprey pass. The empowerment of the local community within the catchment has proven to be one of the most innovative and successful outcomes of the project. In socio-economic terms, the Mulkear River is one of the most important salmon angling rivers in the River Shannon catchment. Ensuring the long-term sustainability of the Atlantic salmon fishery not only protects this species, it also provides an important source of income for the local rural community.
Further information on the project can be found in the project's layman report and After-LIFE Conservation Plan (see "Read more" section).