Vegetation (Floating River Vegetation) - Office of Public Works

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All five Special Areas of Conservation with floating river vegetation as a conservation aspect, namely Lough Corrib (0297), Lower River Suir (2137), River Barrow and River Nore (2162), Lower River Shannon (2165) and the Bandon River (2171) were assessed for this study as they overlapped with Office of Public Work arterial drainage channels. For each SAC in the study, one or more 10km squares were selected for sampling. The main channel maintained by the OPW within the SAC (including the limited extent of the River Nore and the River Suir) along with a number of other channels was surveyed. Sites assessed in the broader sense assisted in the gathering of conservation information and the understanding of floating river vegetation. Channels were selected from an EPA database of channels, based on the Ordnance Survey Discovery vector series. All channels within a 10km square were assigned a random number. The channels were grouped by stream order and, starting with the highest stream order in the square, the channel with the highest random value was selected. Each stream order present was selected in decreasing order and the process was repeated until 10 sample sites had been selected for each square. The survey was carried out between August and September 2006. An exception was the Headford and River Corrib survey square. A series of channels were selected surrounding the Black River, the main channel in the Headford square. As the Black River is predominantly on the County Mayo side of the Lough Corrib SAC, the River Corrib was surveyed as the main channel to conform with ecological methodology. While every attempt was made to survey each site identified on the 10 km survey map some watercourses were inaccessible by foot and could not be surveyed. In such cases an adjacent river of the same stream order was chosen instead. Occasionally, alternative rivers of the same stream order were unavailable reducing the number of sites surveyed within a 10 km square. During the course of the survey the length of each Office of Public Works main channel was walked. Where access to sections of the main channel within the Special Area of Conservation was possible these were also investigated for comparative purposes. GPS locations were determined using a hand held GPS unit (Magellan GPS 315). In the absence of a signal, coordinates for the surveyed watercourses were obtained from an Ordnance Survey Discovery series map. All digital images were obtained using a Canon digital IXUS 65 digital camera. A survey of the back drains of the Ballynaclogh River maintained by the Office of Public Works, which was reported to contain Groenlandia densa, was undertaken on the 26 th February 2007. While the primary objective of the survey was to confirm the presence of G.densa in back drains maintained by the Office of Public Works, other information collected included habitats present, plant distribution, general growth characteristics and the physical parameters of the watercourse colonised by G.densa. 14
3.2 Distribution and extent of floating river vegetation Floating river vegetation was found in a large range of watercourses, however, individual species were restricted in their distribution while other species were ubiquitous. Similarly, a species presence didn't necessarily mean that it was found in abundance in a given habitat. For all watercourses surveyed floating river vegetation diversity was recorded and the dominant species noted for each system. Both maps and identification table have been employed to provide a comprehensive overview of the distribution of floating river vegetation and information on individual plant species identified. Fig. 3 below provides an overview of the sites survey and the presence or absence of floating river vegetation. Fig. 3 An overview map of survey sites assessed for floating river vegetation Floating river vegetation recorded No floating river vegetation recorded A collective map of the provinces of Munster, Connaught and Leinster providing a more de- tailed overview of the presence or absence of floating river vegetation is illustrated in Fig. 4. De- 15
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: 3.0 Ecological Assessment of Water
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 and 34: prevented aquatic growth. Water lev
Page 35 and 36: G.densa was the dominant floating r
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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Vegetation (Floating River Vegetation) - Office of Public Works

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