Controlled Rewilding: Reconciling the Objectives
So, how do we reconcile things? Earlier, we reported on a woodland conservation management policy inclusive of both openand closed-habitat species at the woodland patch scale (Merckx et al. 2012a). Here, we propose another win-win situation, but now within a rewilding context: a conservation management strategy that could reconcile the needs of semi-natural habitat specialists at the regional scale.
The outcome of a management strategy is likely to differ dependent on whether it is applied at the local, landscape or regional scale, and this because species diversity under conditions of low land-use intensity is strongly dependent on spatial scale (see Chap. 1, Fig. 1.2). We here opt for the regional scale, because we believe that within a European context it is more important, and more feasible too, to safeguard a certain species somewhere within a certain region (i.e. regional scale), rather than to safeguard the precise locations of the local populations of that species (i.e. local scale). As such, we consider the relevant spatial scale at which to consider the effects on species composition of the proposed strategy to be the regional (i.e. ca. 100 × 100 km) scale.
Our proposed strategy is not intended to be applied to European regions with fertile agricultural land, but rather to regions characterised by agricultural marginal land. Merckx and Pereira (in press) already warned against an overly agro-centric view on conservation for marginal land, which instead does provide excellent rewilding opportunities. Under our strategy, which we call 'Controlled Rewilding'— combining forest recovery with monitoring and management of semi-natural biotopes—many such regions could evolve towards mosaics including mature climax vegetation, semi-natural biotopes, and natural successional stages, such as river areas, wood gaps and high-altitude areas. Nevertheless, open habitats may be rarer than in pre-historic landscapes, owing to the absence of most former natural herbivores (Merckx et al. 2013), but sun-lit biotopes and grazing can be achieved via other means (see Chap. 8). Eventually, the recovered forests within the resulting mosaics will become more and more dynamic and heterogeneous as a result of natural disturbance regimes operating on a wide range of spatial scales, characteristic of natural forests, and which further enhance biodiversity (Lindenmayer et al. 2006; Lehnert et al. 2013).
We believe there is room within Europe for Controlled Rewilding. It entails both passive abandonment and active (temporary) management interventions to ecologically restore semi-natural biotopes within a rewilding context. As a prerequisite, this strategy needs to include the monitoring of habitat heterogeneity levels at multiple spatial scales. Its aim is to pinpoint where conservation management interventions are required, so as to provide sufficient levels of habitat heterogeneity for specialists of both open and closed biotopes, and at multiple spatial scales in order to cater for
Fig. 6.1 Location of the study area within Portugal. Semi-nested sampling design: Each black dot represents the location of a fixed light-trap sampling site. Sampling occurred at four spatial scales (i.e. 20 × 20 m; 80 × 80 m; 320 × 320 m; 1280 × 1280 m) within each of three 'landscapes' that differed in terms of their dominant land-use cover: (i) 'Forest-dominated': the southernmost 'landscape' was mainly characterised by native, semi-natural forest, (ii) 'Shrub-dominated': the middle 'landscape' was mainly characterised by scrubland, and (iii) 'Meadow-dominated': the northernmost 'landscape' was mainly characterised by extensively managed meadows
small-sized (less mobile) and large-sized taxa (see above). In our opinion, conservation focused on semi-natural biotopes and rewilding should be complementary, via a Controlled Rewilding strategy, and now is the time to designate regions within Europe where both approaches could be combined (see Chaps. 2 and 11).