Provision of Drone Surveys of Bundorragha River, Mweelrea/Shreefry/Erriff Complex SAC

Tender description

The Mweelrea/Sheeffry/Erriff Complex Special Area of Conservation (SAC) covers a large area of the scenic hills of south Co. Mayo, containing a wide range of habitats, supports populations of rare and threatened plants (mosses, liverworts, stoneworts, ferns and flowering plants) and animals (invertebrates, fish, birds and mammals) including many that are listed on the Annexes of the E.U. Habitats Directive. The Bundorragha River flows out of Fin Lough and holds one of the most important freshwater pearl mussel (Margaritifera margaritifera) populations in Ireland and has been identified as a conservation priority by the National Parks and Wildlife Service of the Department of Housing, Local Government and Heritage. The Bundorragha river catchment includes a series of other interconnecting lakes in a valley between the Mweelrea Mountains and the Sheeffry Hills. These lakes consist of the larger Doo Lough, with Glencullin Lough and Lough Cunnel further upstream. Between Doo Lough and Fin Lough flows the Owengarr River. Below Fin Lough the Bundorragha River flows directly south for just over two kilometres into Killary Harbour. The freshwater pearl mussel (Margaritifera margaritifera) is listed on Annex II and Annex V of EU Habitats Directive, and is protected under the Irish Wildlife Acts (1976 and 2000). It is considered to be critically endangered in Ireland (Byrne et al., 2009) and Europe (Moorkens, 2011). The conservation status of the species was bad, when reported under Article 17 of the Habitats Directive in 2007, 2013 and again in 2019 (Moorkens et al., 2007, NPWS, 2013, NPWS 2019). Like most species of freshwater bivalve, the freshwater pearl mussel is threatened by loss, fragmentation and degradation of habitat, overexploitation, pollution, introduction of non-native species and climate change (Dudgeon et al., 2006; Geist, 2010, 2011). Large or small weirs and impoundments can damage freshwater mussel species by altering the physical characteristics of the aquatic ecosystem and resulting in shifts from lotic to lentic conditions in upstream habitats, which have the potential to negatively affect mussel habitat through changes in sediments, river flow and temperature (Mueller et al., 2011). Riverbank erosion in the Bundorragha is a significant pressure and threat to the important Atlantic salmon, sea trout and brown trout populations in the river system, as well as to the freshwater pearl mussel. Furthermore, as a very important angling tourism resource, it is a significant concern to the owners of the fishery, the Delphi Lodge (http://www.delphilodge.ie/). Erosion of the Bundorragha river bank has resulted in kills of adult and juvenile mussels on at least two occasions since 2010. The purpose of this request for tender is to procure scientific support to carry out drone surveys of the Bundorragha and Ownaglocha river channel and riparian zone (c. 60 ha). The purpose of the survey is to establish a detailed baseline of the river channel to understand the changes in river morphology over time. The Mweelrea/Sheeffry/Erriff Complex Special Area of Conservation (SAC) covers a large area of the scenic hills of south Co. Mayo, containing a wide range of habitats, supports populations of rare and threatened plants (mosses, liverworts, stoneworts, ferns and flowering plants) and animals (invertebrates, fish, birds and mammals) including many that are listed on the Annexes of the E.U. Habitats Directive. The Bundorragha River flows out of Fin Lough and holds one of the most important freshwater pearl mussel (Margaritifera margaritifera) populations in Ireland and has been identified as a conservation priority by the National Parks and Wildlife Service of the Department of Housing, Local Government and Heritage. The Bundorragha river catchment includes a series of other interconnecting lakes in a valley between the Mweelrea Mountains and the Sheeffry Hills. These lakes consist of the larger Doo Lough, with Glencullin Lough and Lough Cunnel further upstream. Between Doo Lough and Fin Lough flows the Owengarr River. Below Fin Lough the Bundorragha River flows directly south for just over two kilometres into Killary Harbour. The freshwater pearl mussel (Margaritifera margaritifera) is listed on Annex II and Annex V of EU Habitats Directive, and is protected under the Irish Wildlife Acts (1976 and 2000). It is considered to be critically endangered in Ireland (Byrne et al., 2009) and Europe (Moorkens, 2011). The conservation status of the species was bad, when reported under Article 17 of the Habitats Directive in 2007, 2013 and again in 2019 (Moorkens et al., 2007, NPWS, 2013, NPWS 2019). Like most species of freshwater bivalve, the freshwater pearl mussel is threatened by loss, fragmentation and degradation of habitat, overexploitation, pollution, introduction of non-native species and climate change (Dudgeon et al., 2006; Geist, 2010, 2011). Large or small weirs and impoundments can damage freshwater mussel species by altering the physical characteristics of the aquatic ecosystem and resulting in shifts from lotic to lentic conditions in upstream habitats, which have the potential to negatively affect mussel habitat through changes in sediments, river flow and temperature (Mueller et al., 2011). Riverbank erosion in the Bundorragha is a significant pressure and threat to the important Atlantic salmon, sea trout and brown trout populations in the river system, as well as to the freshwater pearl mussel. Furthermore, as a very important angling tourism resource, it is a significant concern to the owners of the fishery, the Delphi Lodge (http://www.delphilodge.ie/). Erosion of the Bundorragha river bank has resulted in kills of adult and juvenile mussels on at least two occasions since 2010. The purpose of this request for tender is to procure scientific support to carry out drone surveys of the Bundorragha and Ownaglocha river channel and riparian zone (c. 60 ha). The purpose of the survey is to establish a detailed baseline of the river channel to understand the changes in river morphology over time.