## 2 Materials and Methods
### Analysis
#### 2.4.2 Step 2--Habitat Suitability and Connectivity Modelling Using Existing EO and Other Resources  
The ecological information on the basic needs of these species for food, habitat type, dispersal movement, and breeding (Table S3 [98,102, 103]) was integrated with variables such as land cover, crop type, footpaths, topographical parameters, watercourses, settlements, etc., that could be observed in sufficient detail from the EO. These EO-observable variables played an equal role in evaluating the habitat suitability and its connectivity for the studied species. This habitat suitability evaluation process was applied both at the level of the three intensive study sites and also at the whole SH-AONB area level. The following workflow was performed for the EO-based habitat suitability and connectivity modelling:  
1. Choose the environmental variables (factors) based on species habitat and food requirement  
We used 6 different environmental variables, which can be placed into 3 categories including land cover [104], topography [105], and anthropogenic [106] (Table 3). In our modelling, we used land cover (UK CEH LCM2019), crop type (UK CEH Crop Type 2019--only for Skylark), and chalk grassland (priority habitat inventory--only for modelling the Small Blue butterfly suitable habitat) as a means of habitat type, vegetation structure, and food availability. Land cover plays a role as a key variable in this analysis, and it was used to model all habitat suitability of the studied species. The anthropogenic variables selected in this study are footpaths and settlements (urban and suburban areas). These variables (depending on the species-habitat relationship) are likely to affect the connectivity within the habitats. For instance, the settlements vector layer was used as a pressure factor for Skylark nesting habitat; thus, we created a 100 m buffer around the settlement polygons. However, well-managed footpaths and bripleways that cross the broadleaved woodland can be a positive aspect in maintaining a Silver-washed fritillary butterfly population. Moreover, the topographic variable extracted from DEM was needed to ascertain the slope degree, which is an important factor in understanding the small blue butterfly's favoured habitat. 1. Georeferenced species occurrence records  
In this study, the occurrence records of the species were combined with (overlaid on) the results of habitat suitability analysis. This was considered as a further indicator for thepresence of healthy and appropriate habitat, thus reinforcing the potential of a location as suitable for the species. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Score** & **Habitat Suitability** & **Rationale** \\ \hline
1 & Least suitable/unsuitable & Species cannot survive due to the lack of food \\ \hline
2 & Low suitability & Species cannot cross through that area (depending on species and the area size) due to the lack of food. \\ \hline
3 & Moderately suitable habitat & Species may travel through to reach other more suitable areas, but it is unlikely to find food sources. \\ \hline
4 & Suitable habitat & It may be used occasionally but dependant on other factors such as food availability or ideal requirements to sustain a breeding population. \\ \hline
5 & Highly suitable habitat & Provides the best habitat for nesting, breeding, or food (depending on the species). \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Habitat scoring system and rationale.