# Can Vegetation Removal Successfully Restore Coastal Dune Biodiversity?
## 3 Results
### Abundance & Richness  
We tested assemblage-level abundance and species richness to determine whether these parameters were affected by vegetation removal. We considered any result with \(p<0.05\) as significant Full results and \(p\)-values are given in Supplementary Tables S2 and S3. We plotted the results as boxplots where the upper and lower edges of the box correspond to the 25% and 75% quartiles (Figures 2 and 3). The upper whiskers extend from the edge of the box to the highest value, excluding outliers. Data beyond 1.5 of the 25-75% inter-quartile range are outliers and plotted as points. Note that for many of the rodent samples, either one or two species was found. Therefore, for some dune types, the boxplot appears as a single line with no variation. On its own, boxplots for the rodent data would normally not be the most appropriate way to present these results. However, we felt it pertinent to maintain the same graphics across taxa to make them more easily comparable. Figure 2: Boxplots of average abundance for each taxon (see taxonomic icons by row) for (**a–d**) control dunes, (**e–h**) semi-fixed dune treatment, (**i–l**) fixed dune treatment, and (**m–o**) off-road sport vehicle disturbance. Each treated dune type was tested against its untreated pair (control) and mobile (reference) dunes. Disturbed dunes were not monitored for annuals, and untreated semi-fixed dunes were used as the control. Significant differences were tested with generalized mixed models for beetles and reptiles (Poisson), and linear mixed models for rodents and annuals. \(p<0.05\) for treated dunes compared to * control and + reference dunes. We first tested un-treated fixed control and semi-fixed control dunes against the reference mobile dunes, to set up the expectations for treatment effects. There was no difference between control and reference dunes for any of the faunal taxa (Figure 2a-c). This meant we rejected \(H_{1}\) that abundance of animals increases with increasing primary productivity. For annual plants, increasing perennial cover led to increased annual cover as expected (Figure 2d). These findings in control dunes established the expectations for responses to treatment (\(H_{3}\)): For annuals, we expected treatment to result in a decrease in cover, while for animal taxa, no difference was found between control and reference dunes, so no difference would be expected in response to treatment. For the semi-fixed treatment, there was no significant difference in abundance between treated and untreated semi-fixed dunes or mobile dunes for all three faunal taxa (as expected based on the expectations set up in the previous statement (Figure 2b,e-g). In the fixed dune treatment, rodents maintained similar (not significantly different) abundance to un-treated control and mobile dunes, as expected (Figure 2i), while reptile abundance was significantly lower in treated fixed dunes than their control pairs (Figure 2j). Conversely, beetle abundance was significantly higher in treated fixed dunes than both control and reference dunes (Figure 2k). Thus, for reptiles and beetles, treatment did have an effect, despite there being no expectation for any treatment effect. Disturbed dunes exposed to off-road vehicle disturbance were also expected to be more similar to mobile and less similar to untreated semi-fixed control dunes. There was no effect of vehicular disturbance on rodent abundance (Figure 2m). However, reptile abundance was significantly lower on these dunes compared to both mobile and semi-fixed control dunes (Figure 2m). In contrast, beetle abundance was significantly higher in disturbed dunes than in mobile and semi-fixed control dunes (Figure 2o). Figure 3: Boxplots of species richness for each taxon (see taxonomic icons for each row for (**a–d**) control dunes, (**e–h**) semi-fixed dune treatment, (**i–l**) fixed dune treatment, and (**m–o**) off-road sport vehicle disturbance. Each treated dune type was tested against its untreated pair and reference (mobile) dunes.