Vegetation (Floating River Vegetation) - Office of Public Works

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particular interest in this chapter is the G.densa found on the back drains of the River Shannon that flows through Limerick City. Site Code SAC Name Arterial drainage scheme 0216 River Shannon Callow 0458 Killala Bay / Moy Estuary Brosna drainage scheme Moy drainage scheme 2137 Lower River Suir Carrick-on-Suir Flood Relief 2162 River Barrow & River Nore 2165 Lower River Shannon Kilkenny Flood Relief Scheme Ballynaclough, Bunratty-Rineanna, Bushy Island-Martin, Coonagh Embankment, Deel, Feale, Fergus, Foynes, Groody, Maigue Outfall, Mulkear-Ballymackeough, Newtown-Tervoe, Owengarney, Ringmoylan Mellon Table 11 Listed cSAC sites associated with Groenlandia densa, EUNIS website The back drains (i.e. of the River Shannon) are a series of channels at the rear of an embankment that drain the surrounding lands and are normally sluiced through the embankment into the main watercourse. Consequently, vegetation growing in a back drains have adapted to an environment consisting of fluctuations in water levels and large amounts of silt deposition (in the form of land run-off). Habitats adjoining the back drains were described in accordance with Fossitt, 2000. All habitats observed within close proximity to the back drains were recorded. The dominant land habitat type was that of wet grassland (GS4). Field boundaries were denoted by overgrown hedgerows (WL1). Areas of developing scrub predominantly of willow and brambles were observed. To the north west of the back drains are the embankments (ED2) associated with the Ballynaclogh River (FW1). An urban environment consisting of housing estates dominated the east to south side of the back drains. Channel name Surrounding habitat OPW channel Back drains of the Ballynaclough FW1, ED2, GS4, WL1, WS1, BL3 √ River Table 12 Habitat identification adjacent to the back drains colonised by G.densa. SAC status 28
G.densa was the dominant floating river vegetation observed on the back drains of the Ballynaclogh River. Large sections of the back drains were found to support G.densa vegetation. Watercourse sections less densely populated by G.densa vegetation were observed supporting other types of floating river vegetation. A single Ranunculus species with submerged leaves, consistently branching into three would strongly suggest a possible identification of R. trichophyllus. The presence of flowering structure would be needed to confirm the identification. Starworts (Callitriche stagnalis) and water parsnip (Berula erecta) were also observed growing in the back drains. Channel identification Floating river vegetation OPW channel Back drains of the Ballynaclough River Ranunculus trichophyllus, Callitriche stagnalis, Berula erecta, Groenlandia densa √ Table 13 Floating river vegetation observed in back drains. General growth characteristics of G.densa during the survey are listed below. •Wavy leaves are oppositely paired along the stem •Dark green leaves contrast with light green / white stems •New leaf growth appears as a tuft of leaves at the tip of the stem •All leaves are submerged •Coloniser of fine mud sediments •Can develop as a dark green mat close to the water surface. SAC status Fig. 6 Photograph on the left G.densa in its natural habitat (with starworts in bright green). On the right a stem of G.densa beside frog spawn. Note the opposite paired wavy leaves. 29
Page 1 and 2: ISSN 1649 - 9840 SERIES OF ECOLOGIC
Page 3 and 4: Foreword This Ecological Impact Ass
Page 5 and 6: Executive Summary Table of Contents
Page 7 and 8: 1.0 Introduction This study was com
Page 9 and 10: and fauna. The OPW has a multi-annu
Page 11 and 12: Currently twenty-one Special Areas
Page 13 and 14: 2.1.4 Lower River Shannon Special A
Page 15 and 16: 2.2.4 Site elevations within the Lo
Page 17 and 18: 2.3.4 Site integrity of the Lower R
Page 19 and 20: 3.0 Ecological Assessment of Water
Page 21 and 22: 3.2 Distribution and extent of floa
Page 23 and 24: 3.2.1 Floating river vegetation of
Page 25 and 26: aquatic moss. 3.2.3 Floating river
Page 27 and 28: 3.2.5 Floating river vegetation wit
Page 29 and 30: Starwort, Callitriche species •Ro
Page 31 and 32: Each form of reproduction requires
Page 33: prevented aquatic growth. Water lev
Page 37 and 38: 4.0 Description of maintenance oper
Page 39 and 40: consultation with the Foreman / Tec
Page 41 and 42: 4.3 River corridor water dynamics A
Page 43 and 44: Not shown in the above data set is
Page 45 and 46: 4.4 Physical, chemical and biologic
Page 47 and 48: •Survey watercourses to determine
Page 49 and 50: The primary riverbed substrate of w
Page 51 and 52: gravel require loosening assess the
Page 53 and 54: • Livestock should be restricted
Page 55 and 56: River Breagagh Winter 2006 River Br
Page 57 and 58: River Breagagh Winter 2006 Ranuncli
Page 59 and 60: 6.0 Conclusion and summary •Arter
Page 61 and 62: References •Blamey, M., Fritter,
Page 63 and 64: Appendix A - Special Areas of Conse
Page 65 and 66: Lower River Shannon Special Areas o
Page 67 and 68: Channel name Location coordinates E
Page 69 and 70: Appendix C - Habitat classification
Page 71 and 72: Lower River Shannon Special Area of
Page 73 and 74: Lough Corrib Special Area of Conser
Page 75 and 76: 7 Lower River Suir Special Area of
Page 77 and 78: C1 Lower River Shannon Special Area
Page 79 and 80: 6 C1/12/2 C1/18/1/1 /14/7/3 C/20/1
Page 81 and 82: Appendix E - Physical parameters re
Page 83 and 84: River Barrow and River Nore Special
Page 85 and 86:
Latin Name English Name Appendix F
Page 87 and 88:
Latin Name English Name Potamogeton
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