A novel application of the Urban River Survey – Investigating physical habitat

and biotic quality across Greater London Naresh B. Patel MSc Aquatic Resource Management

3. Research Aims

• Investigate relationship between physical habitat quality and biotic quality in Greater London’s urban rivers.

• Potentially validate a novel methodology using URS in conjunction to macroinvertebrate bio-indicators.

References[1] Walsh, C., Roy, A., Feminella, J., Cottingham, P., Groffman, P. and Morgan, R. (2005) The urban stream syndrome: current knowledge and the search for a cure. Journal of the North American Benthological Society, 24(3), 706. [2] Vaughan, I., Diamond, M., Gurnell, A., Hall, K., Jenkins, A., Milner, N., Naylor, L., Sear, D., Woodward, G. and Ormerod, S. (2009) Integrating ecology with hydromorphology: a priority for river science and management. Aquatic Conservation: Marine and Freshwater Ecosystems, 19(1), 113-125.[3] Shuker, L. J., Gurnell, A. M. and Raco, M. (2011) Some simple tools for communicating the biophysical condition of urban rivers to support decision making in relation to river restoration. Urban Ecosystems, 15(2), 389-408. [4] Naura, M., Clark, M. J., Sear, D. A. and Carter, M. G. (2016) Mapping habitat indices across river networks using spatial statistical modelling of River Habitat Survey data. Ecological Indicators, 66, 20-29. [5]Langhans, S., Hermoso, V., Linke, S., Bunn, S. and Possingham, H. (2014) Cost-effective river rehabilitation planning: Optimizing for morphological benefits at large spatial scales. Journal of Environmental Management,

132, 296-303.

4. Methods

• 15 sites over 9 rivers selected (Figure 2).

• URS, macroinvertebrate kick-sample, water physio-chemistry assessed.

• Stretch Habitat Quality Index (SHQI) indicating physical habitat quality from 3 (Very Good) to 18 (Very Poor).

• Shannon Diversity Index (H) and BMWP scores indicating macroinvertebrate biotic quality. Phosphate analysis of water quality.

2. The Urban River Survey

• Urban specific EA-based river habitat survey (RHS)

• Hydromorphological quality and river restoration assessment[3] but untested in relation to biotic quality.

1. The Issue of Urban Rivers

• Engineering/modification for flood control, waste disposal and water abstraction objectives are often prioritised within densely populated areas with high levels of impervious surface cover (ISC) (Figure 1).

• Resulting “flashy” hydrologic regime, reduced rainwater absorption, urban pollution loading and degraded biotic richness is termed The Urban Stream Syndrome[1]

• Disjointed understanding between physical habitat and biotic quality limits ecological quality improvements[2].

Figure 1. The River Brent at TokyngtonPark (site A).

6. Management Implications

• Comprehensive, integrated monitoring and assessment towards EU WFD objectives.

• High resolution, continuous catchment mapping of London’s urban rivers[4].

• More cost-effective targeting for physical habitat restoration or water quality improvements[5].

• Citizen science and behavioural change applications via MoRPh survey.

Naresh B. Patel, BSc (Hons)naresh.patel@kcl.ac.uk nareshbpatel1992@gmail.com 07531246038

5. Results

• Strong negative relationships (r = -0.634, p<0.05) (r= -0.716, p<0.05) (Figure 3) indicated as urban river physical habitat improves an increase in biotic quality of macroinvertebrates is also observed (Figure 4).

• PCA specifically described bank-naturalnessand in-channel heterogeneity across the 15 sites as strong predictors of biotic quality.

• Water quality influence also key within urban systems adding interaction complexity.

Figure 4. Ewell Court Park, Hogsmill (site I).

Figure 2. Map of study sites across Greater London.