Page 13 - A bird’s-eye view of recreation - Rogier Pouwels

sensitive to disturbance by visitors (Blanc et al., 2006, Sutherland et al. 2006), even at 1 low visitor densities (Bötsch et al 2017).
1.2 Credibility, legitimacy and salience of current knowledge concerning the impact of recreation on bird populations
To prevent or reduce conflicts between birds and hikers in nature areas, site managers rely on scientific knowledge (Buckley 2013, McCool 2016). However, current scientific knowledge is inconclusive and can support different, sometimes contradictory opinions about the nature and gravity of the problem and about which solutions are effective (Sarewitz 2004, Patt 2007). Marzano and Dandy (2012) even concluded that the widespread perception that recreation has a negative impact on nature values in forests is only partly supported by evidence. The existence of contradictory opinions makes it difficult to find new and alternative solutions in decision-making processes as both stakeholders and experts who hold opposing views will be able to find scientific evidence to support their particular point of view (Brown and Duguid 2000, Deelstra et al. 2003). An example of contradictory evidence on the potential negative impact of outdoor recreation on nature values concerns the Black Grouse (Tetroa tetrix). This bird is considered to be very sensitive to disturbance by hikers (Suchant and Braunisch 2004, Signorell et al. 2010), but Baines and Richardson (2007) were not able to detect differences in fecundity and survival of Black Grouse between different levels of disturbance. However, Steven et al. (2011) showed that in 61 out of 69 studies a negative impact of recreation on bird species was found and Bötsch et al. (2017) recently showed that even low levels of disturbance lead to a decrease in breeding bird territories and also species richness. Although reviews state that, in general, outdoor recreation has a negative effect on bird species, there is no conclusive scientific evidence that this applies to all species in all situations (Hill et al. 1997, Blanc et al. 2006, Whitfield et al. 2008, Steven et al. 2011).
Why is evidence from empirical research not conclusive? There may be two explanations for this ambiguity. A first and obvious explanation is that species respond differently because they differ in sensitivity to disturbance (Blanc et al. 2006, Møller 2008, Steven et al. 2011). Sensitive species tend to be species that breed or forage in open landscapes like heathlands (Yalden and Yalden 1990, Murison et al. 2007, Langston et al. 2007), open grasslands (Kerbiriou et al. 2009) and beaches (Burger 1995, Lord et al. 2001). Other species shown to be sensitive to disturbance include species that
General introduction
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