Page 15 - A bird’s-eye view of recreation - Rogier Pouwels

General introduction
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Figure 1. Measured effects and impacts of visitor disturbance on birds and bird populations (adapted from Steven et al. 2011 and Le Corre et al. 2009). The higher the degree of disturbance, the more likely it is that long-term impacts will be detected. The degree of disturbance (on the x-axis) depends on many factors, such as the number of visitors, the type of activity, the period in which the activity takes place, and the landscape. At low levels of disturbance, individual impacts, such as behavioural change, can be detected by direct observation. Impacts on (meta)population size and viability can only be detected at high levels of disturbance during long-term investigations.
detecting impacts at larger spatial scales is more difficult because other factors, such as changes in land use and climate change, have to be taken into account (Young et al. 2005). Impacts from these factors might even exceed impacts from recreation, making these even harder to detect (Gutzwiller et al. 2017). Nevertheless, taking large spatial scales into account is essential for an adequate assessment of the impact on population size and viability (Buckley 2013, McCool 2016, Gutzwiller et al. 2017).
A further complication with regard to scale is that most management actions are implemented at a local scale, while bird population viability is determined at a spatial scale that includes multiple nature areas (Suárez-Seoane et al. 2002, Suchant and Braunisch 2004, Opdam and Wascher 2004). The persistence of bird species depends on the dynamics within and between different populations (Opdam 1991, Hanski 1999, Opdam et al. 2003) and for many species, conservation depends on the presence of a network of nature areas at a regional or even biogeographical scale (Gaston et al. 2006, Cabeza and Moilanen 2001, Martensen et al. 2012). Therefore, site managers need information not only on the local situation but also about other areas. One of the main challenges is that managers from these different areas need to determine who is responsible for taking action to realize conservation objectives (EC 2014). According to
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