This document discusses the importance and vulnerability of small stream networks in Ireland. Some key points: - Small streams comprise over 77% of Ireland's river network but represent just 10% of EPA monitoring sites. - They play an important role in biodiversity, water quality downstream, and as habitat for species like salmonids. However, they are also very vulnerable to pollution and other stressors due to their narrow channels and low dilution capacity. - Several studies examined macroinvertebrate communities and water quality in small streams across Ireland, finding high biodiversity and vulnerability to pollution.

1. The importance and vulnerability of our small stream network
Mary Kelly-Quinn, UCD. Email: mary.kelly-quinn@ucd.ie

2. Almost 77% of the river network in Ireland comprises first and second order streams
Represented by just over 10% of sites in the EPA monitoring programme
See: McGarrigle, M. (2014) Assessment of small water bodies in Ireland. Biology and Environment: Proceedings of the Royal Irish Academy 114B, 119-128. Special Issue on Small Water Bodies.

3. Why consider small streams?
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Small stream capture considerable volume of water
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Influence water quality in downstream reaches
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Spawning and nursery area for salmonids

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Important in terms of catchment biodiversity. Up to 29% of aquatic macroinvertebrate species are unique to headwaters – function of stream heterogeneity
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Support species common to further downstream
Number of taxa unique (blue)to each distance and common to various distances (Rivers Bilboa, Mulkear & Tar)
For more detail see: Callanan, M., Baars, J-R. & Kelly-Quinn, M. (2014) Macroinvertebrates of Irish headwater streams: contribution of catchment biodiversity. Biology and Environment: Proceedings of the Royal Irish Academy 114B, 143-162. Special Issue on Small Water Bodies

5. 
Some headwater areas are species-rich & may in the future be extremely important sink populations.
From: Feeley, H.B. & Kelly-Quinn, M. (2012) An evaluation of local and regional diversity of benthic macroinvertebrate communities in two small regions of Ireland and their potential refugia for certain taxonomic groups. Biology and Environment: Proceedings of the Royal Irish Academy 112B, 1, 43-54.

6. Stressors on small streams
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Particularly vulnerable to pollution
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Narrow channel – high land-water interface
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Low dilution capacity
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Point & diffuse pollution
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Chronic & acute
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Multiple pressures
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Gortinlieve Catchment, Donegal
Data from: Pathways Project
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Nitrate (mg/l N)
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7. Lowland streams
SpringSummerAutumnWinterSpringGoodModeratePoor
Glen Burn Stream – Pathways Project
Nutrient & Sediment Inputs

8. River Ow, Wicklow From: Hydrofor Report (J. Clarke)
Upland streams
Sites in west of Ireland – Hydrofor Project
See: Feeley, H.B., Bruen, M., Blacklocke, S. Baars & Kelly-Quinn, M. (2013) Science of the Total Environment 443, 173-183.

9. Richness
Abundance
Change in water level(cm)
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See: Feeley, H.B., Davis, Stephen, Bruen, M. Blacklocke, M. & Kelly-Quinn, M. (2012) Journal of Limnology, 71, 2, 309-318.

10. Editors: M. Kelly-Quinn & J-R Baars Thanks to EPA for sponsorship
Available online December 10th
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Increase awareness
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‘Boots on the ground’
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Target research to address knowledge gaps
Extent of Small Streams Risk Score monitoring in support of Characterisation and development of the WFD monitoring programme during 2005–2006.
Action needed