Quantifying the importance of multi‐scale management and environmental variables on moorland bird abundance

Abstract

UK moorlands are semi-natural habitats managed for a mix of livestock, game shooting and forestry, among other activities. An assessment of the importance of characteristics that correlate with moorland bird populations of high conservation importance can inform appropriate management at appropriate locations. We use hierarchical partitioning to assess the absolute and relative importance of climate, topography, soil, landscape management (wider scale habitat configuration of forestry and agriculture) and site-based management (indices of predator control, and vegetation characteristics) in determining the abundance of a suite of upland birds in four regions of the UK. Unmeasured regionspecific effects often made the largest contribution to models. Physical characteristics (climate, topography, soil) were important and on average explained a similar amount of variation to site-based management. However, there was considerable interspecific variation in the importance of both. Landscape-scale variables were generally of low importance. An index of predator control was positively correlated with the abundance of Red Grouse Lagopus lagopus scotica and two waders. Vegetation characteristics (composition and structure) were, together, strong correlates of the abundance of passerine species. Vegetation characteristics were as important as indices of predator control for waders and grouse. The importance of regional effects, physical characteristics and variables relating to management suggest targeting site-based management (such as predator control or vegetation management) to the areas where physical characteristics are most favourable. The most beneficial management will vary between species, necessitating a mosaic of management options across upland areas to benefit all species.

Population responses of Red Grouse Lagopus lagopus scotica to expansion of heather Calluna vulgaris cover on a Scottish grouse moor

“…Grouse productivity was also higher in years with management for grouse but was not related to grazing intensity. This is consistent with other studies suggesting that predation has a stronger effect than habitat quality on population growth of Red Grouse (e.g., Thirgood et al 2002, Fletcher et al 2010, and with the positive effect of predator control on other ground-nesting birds (Pearce-Higgins and Yalden 2003, Fletcher et al 2010, Douglas et al 2014, Buchanan et al 2017, Ludwig et al 2017.…”

Evaluating the effectiveness of conservation measures for European grassland‐breeding waders

“…However, the most effective use of particular interventions requires considering their specific timing, duration, and intensity and the characteristics of the particular site or habitat. For example, due to contrasting habitat requirements, intervention responses may vary between species breeding at the same site (e.g., Buchanan, Pearce‐Higgins, Douglas, & Grant, ) and may have contrasting impacts on occupancy and abundance, productivity, and survival. Our assessment provides only a broad evaluation of the overall patterns, whereas responses are likely to vary with local context.…”

The influence of different aspects of grouse moorland management on nontarget bird assemblages

“…Among waders, such a relationship has been reported for European golden plover, northern lapwing Vanellus vanellus and Eurasian curlew (e.g., Baines, Redpath, Richardson, & Thirgood, 2008;Buchanan, Pearce-Higgins, Douglas, & Grant, 2017;Newey et al, 2016;Tharme, Green, Baines, Bainbridge, & O'Brien, 2001; see Table 1) while studies focussing specifically on Eurasian curlew have also shown a positive correlation of abundance with gamekeeper activity (Douglas et al, 2014;Franks, Douglas, Gillings, & Pearce-Higgins, 2017). Among waders, such a relationship has been reported for European golden plover, northern lapwing Vanellus vanellus and Eurasian curlew (e.g., Baines, Redpath, Richardson, & Thirgood, 2008;Buchanan, Pearce-Higgins, Douglas, & Grant, 2017;Newey et al, 2016;Tharme, Green, Baines, Bainbridge, & O'Brien, 2001; see Table 1) while studies focussing specifically on Eurasian curlew have also shown a positive correlation of abundance with gamekeeper activity (Douglas et al, 2014;Franks, Douglas, Gillings, & Pearce-Higgins, 2017).…”

“…Previous studies have generally shown a positive relationship between grouse moor management and populations of red grouse and of ground-nesting waders. Among waders, such a relationship has been reported for European golden plover, northern lapwing Vanellus vanellus and Eurasian curlew (e.g., Baines, Redpath, Richardson, & Thirgood, 2008;Buchanan, Pearce-Higgins, Douglas, & Grant, 2017;Newey et al, 2016;Tharme, Green, Baines, Bainbridge, & O'Brien, 2001; see Table 1) while studies focussing specifically on Eurasian curlew have also shown a positive correlation of abundance with gamekeeper activity (Douglas et al, 2014;Franks, Douglas, Gillings, & Pearce-Higgins, 2017 Newey et al, 2016;Tharme et al, 2001). While crows are directly controlled on grouse moors, other species may be impacted by grouse moor management producing suboptimal habitat, relative to other upland areas that are not managed for sporting purposes.…”