Page 53 - A bird’s-eye view of recreation - Rogier Pouwels

For the Skylark, Vos and Peltzer (1987) found a reduction of more than 50% in a zone of 40 meter when visitor densities were 5 groups per hour and a reduction of 100% in a zone of 40 meter when visitor densities were 20 groups per hour. These parameters were extrapolated to disturbance zones (Table 3). These parameters were used to define a buffer zone surrounding each path segment. Within the buffer zones, the density was reduced by 50%.
Table 3. Size of disturbance zone produced by varying sized groups of visitors used in the models.
Number of groups Disturbance zone (m)
0-1 30
2-5 60 3 6-15 100
16-30 200
31-60 300
61-100 400
>100 600
Little is known about the reduction in reproduction success for Skylark. For Stonechat (Saxicola torquata), the percentage of nests that were abandoned in disturbed zones is 75% and for Curlew (Numenius arquata) the percentage is 64% (Vos and Peltzer 1987). Based on expert judgement, we chose a low reduction in reproduction of 25% in disturbed zones.
Because the impact is expressed as visitor impact for one day and the viability of the Skylark is simulated over 100 years the time scale of MASOOR differs greatly from the time scale of METAPHOR. MASOOR uses discrete event simulations (see Jochem et al. 2007) and METAPHOR uses discrete time steps (Vos et al. 2001).
3.5 Results
In the area, 11 populations can be distinguished. Some of the populations are completely within disturbance zones of recreation, while others are more or less disturbance free (Fig. 5a and 5b). In the zoning scenario, all paths near population 5, 6, 7 and 8 and two paths through population 4 have been closed (Fig. 5b).
Linking ecological and recreation models
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