Water quality is a poor predictor of recreational hotspots in England

Maintaining and improving water quality is key to the protection and restoration of aquatic ecosystems, which provide important benefits to society. In Europe, the Water Framework Directive (WFD) defines water quality based on a set of biological, hydro-morphological and chemical targets, and aims to reach good quality conditions in all river bodies by the year 2027. While recently it has been argued that achieving these goals will deliver and enhance ecosystem services, in particular recreational services, there is little empirical evidence demonstrating so. Here we test the hypothesis that good water quality is associated with increased utilization of recreational services, combining four surveys covering walking, boating, fishing and swimming visits, together with water quality data for all water bodies in eight River Basin Districts (RBDs) in England. We compared the percentage of visits in areas of good water quality to a set of null models accounting for population density, income, age distribution, travel distance, public access, and substitutability. We expect such association to be positive, at least for fishing (which relies on fish stocks) and swimming (with direct contact to water). We also test if these services have stronger association with water quality relative to boating and walking alongside rivers, canals or lakeshores. In only two of eight RBDs (Northumbria and Anglian) were both criteria met (positive association, strongest for fishing and swimming) when comparing to at least one of the null models. This conclusion is robust to variations in dataset size. Our study suggests that achieving the WFD water quality goals may not enhance recreational ecosystem services, and calls for further empirical research on the connection between water quality and ecosystem services

Schematic diagram of the different steps undertaken within the analysis.

<p>Multiple data sources were combined (+), compared relative to each other (/) and tested against defined criteria (?). Colors match respective Methods sections: (i) Recreation use data curation (green); (ii) Water status and geospatial data (blue); (iii) Null models (orange); (iv) Statistical analysis (purple).</p

Association of good/high overall water status and use of cultural ecosystem services for the eight River Basin Districts.

<p>The Odds Ratio (<i>OR</i>) of each River Basin District measures the likelihood that actual visits take place in sites characterized by good/high overall water status compared to random locations selected under a null model accounting for demand and substitutability (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166950#pone.0166950.t002" target="_blank">Table 2</a>). <i>OR</i> exhibits a statistically significant positive (negative) association (i.e. visits in good/high overall water status sites are more (less) common than random; solid colours) if the 90% confidence interval is completely above (below) the line <i>OR</i> = 1. The robustness of the results is tested by comparing null models, including a null model without weighting. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166950#pone.0166950.g002" target="_blank">Fig 2</a> for River Basin Districts acronyms.</p

Data obtained from individual River Basin Management Plans (Environment Agency, 2015) and Land Cover Map of Great Britain 2007 [31].

<p>See inset in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166950#pone.0166950.g002" target="_blank">Fig 2</a> for location of River Basic Districts.</p

Available datasets for cultural ecosystem services use in rivers, canals and lakes across England.

<p>Geo-referenced visitation data from the Managing Engagement with the Natural Environment (MENE, Natural England 2009–2014; <i>n</i> = 4459); boating visits in the Watersports Participation Survey (British Marine, MCA, RNLI, RYA, British Canoeing and CEFAS 2014; <i>n</i> = 1298); fishing sites on fishinginfo.co.uk (Angling Trust 2015; <i>n</i> = 816); and outdoor swimming sites on wildswim.com (Outdoor Swimming Society 2015; n = 565). Inset shows the locations of the eight River Basin Districts in England (north to south): Northumbria (NB), North West (NW), Humber (HU), Anglian (AN), Severn (SV), Thames (TM), South East (SE) and South West (SW). Only points near (≤1km) of a river body with a reported ‘overall water status’ (i.e. WFD water quality standard) in 2014 were included.</p

Null models for the expected % of visits in good/high overall water status sites.

<p>Null models for the expected % of visits in good/high overall water status sites.</p