Restoration goals: Why are fauna still overlooked in the process of recovering functioning ecosystems and what can be done about it?

Abstract

The project arose from knowledge gaps identified through a literature review of fauna responses to mine site restoration, and an interest in stimulating further discussion on this topic at a time where such discussion will contribute to the international debate of what constitutes effective restoration..Summary Despite the evidence that fauna play complex and critical roles in ecosystems (e.g. pollination and nutrient cycling) and the knowledge that they need to be considered in restoration, fauna often remain poorly represented in restoration goal setting, monitoring and assessments of restoration success. Fauna clearly are integral to the aspirations of achieving full ecosystem recovery. However, over-reaching assumptions about the unassisted return of fauna to restored sites, low investment in fauna monitoring, and minimal consideration of the requirements for fauna monitoring in regulatory guidance and standards appear to have led to the historically vegetation-centric approaches to rehabilitation and ecological restoration. We argue that ecological complexities render assumptions of unassisted fauna return inappropriate in many situations and may represent a missed opportunity to enhance ecological outcomes and improve restoration trajectories. We advocate for greater consideration of fauna as facilitators of ecological restoration and, particularly for well-funded projects, for monitoring to place greater emphasis on examining the behaviour and resilience of restored fauna communities. There is a clear need for both industry and regulators to recognise that fauna can be crucial facilitators of restoration and appreciate that the return and monitoring of functional faunal communities can be costly, challenging and may require detailed study across a wide range of taxonomic groups. Failure to advance from business as usual models may risk leaving a legacy of ostensibly functional, but biodiversity-depauperate, restored ecosystems.

Using monitors to monitor ecological restoration: Presence may not indicate persistence

“…Habitat loss and degradation through anthropogenic activities such as agriculture, urbanisation and mining, is a leading driver of species extinctions worldwide (Lande 1998;Tilman et al 2001;Fahrig 2007;Cristescu et al 2012). Consequently, there has been growing recognition of the importance of returning degraded habitats to pre-disturbance conditions (Standards Reference Group SERA 2017;Miller et al2017;Gann et al 2019;Cross et al 2020a). Historically, there has been an emphasis placed upon assessing vegetation structure and community dynamics in post-restoration monitoring (Ruiz-Jaen & Mitchell Aide 2005;Koch et al 2010).…”

“…Historically, there has been an emphasis placed upon assessing vegetation structure and community dynamics in post-restoration monitoring (Ruiz-Jaen & Mitchell Aide 2005;Koch et al 2010). Consequently, animal taxa are often overlooked in assessments of restoration success (Lindell 2008;Cross et al 2019;2020a) despite their role in providing critical ecological services, such as soil decomposition (Jouquet et al 2006;Lavelle et al 2006), pollination (Phillips et al 2010;Menz et al 2011;Frick et al 2014) and regulation of predator-prey dynamics (Mace et al 2012).…”

“…The 'Field of Dreams' hypothesis, or 'build it and they will come' (Palmer et al 1997), assumes that animal taxa will return to habitats following the restoration of vegetation (Block et al 2001;Cristescu et al 2012;Cross et al 2020a). Few studies, however, have demonstrated that the return of vegetation and habitat structure promote the unassisted return of fauna, or their re-integration into ecological processes, to a level comparable to that of the pre-disturbance habitats (Hilderbrand et al 2005;Cross et al 2020a). Among existing studies of fauna responses to restoration, there is a strong focus towards assessments of species' presence, absence or abundance within restored habitats (Lindell 2008;Cross et al 2019).…”

“…Among existing studies of fauna responses to restoration, there is a strong focus towards assessments of species' presence, absence or abundance within restored habitats (Lindell 2008;Cross et al 2019). While providing important tools for assessing population dynamics and habitat quality (Mackenzie 2005), such studies risk failing to provide sufficiently detailed information on the complexities of ecological interactions within habitats (Aldridge & Boyce 2007;Lindell 2008;Cross et al 2020a) and have a high chance of missing rare or cryptic species due to capturing only a 'snapshot' of biodiversity (Chiarucci et al 2011). Successful restoration of degraded sites may hinge on both presence and abundance of key resources in restoration (Lindell 2008).…”

“…Understanding the behavioural responses of animals to habitat change and restoration, and the complex environmental factors facilitating their persistence and viability in habitats, is fundamental to achieving successful restoration outcomes (Sutherland 1998;Lindell 2008;Hale & Swearer 2017;Cross et al 2019Cross et al , 2020a. Monitoring visible signs of the presence of animals in habitats, such as tracks, burrows and diggings, provides an effective method for indirectly assessing behavioural and movement ecology (Gese 2001;Jewell et al 2001;Stephens et al 2006), particularly for shy or cryptic species where visual observations can be challenging (Silveira et al 2003;Balme et al 2009).…”