# Can Vegetation Removal Successfully Restore Coastal Dune Biodiversity?
## 1 Introduction
Once established, nutrients build up in the sand around their bases, facilitating the establishment of successional species, and in turn, leading to dune fixation [5; 51; 52]. New embryonic dunes forming at the beach would usually replace fixed dunes in a continuous cycle. Established dunes can also alternate between mobile and stable states following climatic perturbations or other disturbances in longer cycles [24; 53]. Removal of disturbances from the system, such as removal of human activity or changes in wind and sand deposition, can lead to loss of this cycle. In Wales, rapid dune fixation occurred over the last 60 years after rabbits that had maintained dune perturbation were nearly all wiped out due to extermination and disease [15]. In New Zealand and California, shrub encroachment by invasive species resulted in extensive dune fixation [25; 32]. Removal of perennial vegetation has been shown to be an effective tool for reinstating the geomorphological traits of naturally occurring mobile dunes [15; 24; 54; 55; 56]. This restoration approach may seem unconventional because a) it involves the intentional introduction of an anthropogenic disturbance, b) it aims to restore an earlier successional state, as opposed to passively allowing natural vegetation succession to continue. However, it is argued that sand dynamics in most coastal dune ecosystems no longer function naturally due to restrictions of sand movement along the beachfront and inland [57]. Therefore, human intervention and introduction of disturbance is needed to restore the dunes. In general, ecological restoration projects are widely reported, but are rarely evaluated systematically, particularly on mid- and long-term temporal scales [2; 58; 59]. Lack of clearly defined and measurable restoration targets also makes evaluation of manipulation responses difficult [2; 60; 61; 62]. Restoration can involve abiotic and biotic manipulations; if the goal of a restoration project is to restore biodiversity and improve ecosystem functioning, the recovery of biotic components of ecosystem processes across multiple trophic levels must be understood [63; 64; 65; 66]. Restoration of coastal dune systems should therefore consider the response of both faunal and floral species. Biotic responses are often not reported in landscape restoration, and rarely for animal taxa [59; 67]. Most coastal restoration projects only consider geomorphological and vegetation components, and usually are only monitored over a short time frame. Only a handful of coastal restoration studies evaluate more than one taxon concurrently, and a recent review [2] found that 88% of coastal restoration studies only considered plant responses, usually only in terms of vegetation cover or species richness, not composition. There is a clear need for a coastal restoration studies involving vegetation removal to consider responses of species composition over a long timeframe and across multiple taxa (particularly faunal taxa). We found only one study that investigated composition responses of multiple taxa (arthropods and plants) to disturbance in coastal dunes [49], while [PERSON] et al. [68] are the only authors to consider animal and plant responses to vegetation removal concurrently. The Nizzanim Dune Nature Reserve (NDNR), on the southern Mediterranean coast of Israel, provides a rare opportunity to conduct a restoration study considering all these components. Livestock grazing and firewood collection by nomadic tribes was prevalent for hundreds of years in what is now NDNR [69; 70; 71]. Exclusion of this anthropogenic presence since the middle of the last century has led to substantial shrub encroachment and dune fixation across the reserve [69; 72]. It is expected that in the absence of disturbance, the dunes in NDNR will eventually homogenize and become fixed, which will result in the loss of mobile dunes and their associated species, and an overall loss of \(\beta\)- and \(\gamma\)-diversity across the reserve [26].