Page 57 - A bird’s-eye view of recreation - Rogier Pouwels

Models are inherently sensitive to modification of input parameters. The predicted
numbers of Skylark in the scenario of the current situation are 3 times higher than the
actual numbers over the last years (personal communication with Antje Ehrenburg).
Although the simulation defines the metapopulation as viable, a small change in
parameter settings can cause much lower estimates of breeding pairs. The lower
numbers in the current situation could also be attributable to other stress factors
not considered in the simulations. A land cover map from 1990 was used, possibly overestimating open areas and carrying capacity. Successional changes in vegetation
of some open dune areas may have led to the production of smaller patches and
lower estimates of breeding pairs. In the case study, the Skylark populations in the Amsterdamse Waterleidingduinen are considered as a metapopulation on its own. In 3 the agricultural areas to the East there is a large population of Skylarks. Because this
population is declining also, the number of dispersal events to the dune area is difficult to estimate, but the large population will have at least a small positive effect on the actual population in the dune area.
Although both recreation and ecological models are being developed further, more effort should be put in the combination of these models. The integrated models should organize ecological, managerial and recreational information in a related manner, and subcomponents of the respective models should influence each other (Haider 2006). The output of recreation models should allow managers to place value on different aspects of the recreation experience as well as impact of recreation on nature. Also the impact of nature (development) on recreation should be implemented (grey arrows in Fig. 3). Do people appreciate the typical song of the Skylarks on sunny days? Visitors have strong preference for the preservation of species richness and scenic beauty. However, when there is a trade-off between these benefits visitors chose their favourite scenery at their favourite recreation site and prefer management options, which preserve biodiversity at other sites in an area (Horne et al. 2005). Visitors don't like to see changes in their own backyard.
In the case study no clear recreation goals were stated by the managers. In northwestern Europe, recreation goals are rarely specified. However, clear goals and thresholds are needed when future planning scenarios are to be comparatively evaluated and when recreation goals and nature goals need to be optimized. Integration of recreation and nature functions cannot be accomplished in the absence of explicitly stated goals. We think that the lack of clear goals is one of the reasons why modelling frameworks
Linking ecological and recreation models
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