Gravel pits: recreational conflicts perceived by anglers

In many areas of Germany, so-called gravel pits - small water bodies (1 – 30 ha of extension) artificially created by excavation of non-renewable natural resources such as sand, clay or gravel - constitute the most numerous... [ view full abstract ]

In many areas of Germany, so-called gravel pits - small water bodies (1 – 30 ha of extension) artificially created by excavation of non-renewable natural resources such as sand, clay or gravel - constitute the most numerous lake ecosystems. These novel ecosystems provide secondary habitats for colonization by a diverse natural community of animals and plants, and they provide a wide range of ecosystem services, especially cultural services related to recreation. In Germany, many gravel pits are managed for fisheries by anglers who focus their initiatives on managing fish stocks and littoral zones. Other recreational activities commonly present at gravel pits include swimming/sun bathing, pleasure boating, wildlife viewing and walking. These outdoor recreational activities may reduce the value of the ecosystem service of angling if anglers perceive the presence of other user groups negatively. Our objective was to assess the ecosystem services generated by gravel pits as perceived by anglers, while investigating the (dis)benefits to anglers generated by the presence of endangered biodiversity and other recreational users. To that end, we designed a stated choice experiment (CE) using a novel spatial choice task that described key attributes of possible importance to anglers using visually varying attributes. We invited a random sample of 5,500 anglers from 10 fishing clubs in Lower Saxony to respond to the choice experiment regarding the future management of these lakes (40% response rate). We asked both for discrete preferences and hypothetical allocation of days to the various options to separate preferences from behavioural consequences as perceived by anglers. N = 1900 Respondents preferred lakes hosting abundant forage and predatory fish stocks as well endangered species (both fish and other - aquatic and non-aquatic - species). The perceived utility of the presence of endangered fish was larger than the utility of endangered other organisms, but the presence of endangered non-fish organisms at or around the lake (birds, amphibians etc.) would reduce the use intensity of the lakes by anglers. Regarding recreational uses, a strong potential for conflict especially with bathers was revealed. Also walking around the shores and using pleasure boats on average reduced the quality of gravel pits for anglers, but only the presence of swimmers and pleasure boaters would reduce the actual visitation rates. However, preference heterogeneity was revealed using latent class models in relation to aversion of alternative outdoor recreation uses. Of the three angler types, one expressed a preference towards allowing walking and boating on the small lakes, revealing much more tolerance towards other recreational uses than two other angler classes. Overall, our study suggests that optimizing outdoor recreational experiences for anglers would involve constraining other water body users. Thus, optimizing the total bundle of ecosystem services produced by a landscape of gravel pit lakes probably involves a zoning approach.