# Habitat Loss and Other Threats to the Survival of _Parnasius apollo_ ([PERSON], 1758) in Serbia
## 3 Results
### Temporal Trends in Vegetation Types and Their Association with Butterfly Presence  
To examine the relationship between vegetation dynamics and butterfly presence, we analyzed trends in three key vegetation types--Exposed Soil, Grass, and Shrubs and Trees--across six locations over the period 2015-2024. The data were categorized into two groups: locations with butterflies (LOK 1 and LOK 3) and those without butterflies (the remaining four locations). For each vegetation type, we visualized the temporal changes in percentage coverage, distinguishing between the two groups using different colors. This approach allowed us to assess not only the general patterns of vegetation change but also the stability and consistency of these trends across the two categories. The resulting graphs provide a clear comparative view of vegetation dynamics and their potential influence on butterfly habitat suitability. The plots were created using Python (version 3.10.12), employing the Matplotlib (version 3.8.0) library for visualization. The analysis of vegetation trends over the period 2015-2024 reveals clear distinctions between locations with and without butterflies, emphasizing the importance of specific vegetation structures in maintaining suitable habitats. For Exposed Soil (Figure 5), the data demonstrate that locations with butterflies (LOC 1 and LOC 3) consistently maintain low levels of exposed soil, typically below 10%. This stability contrasts sharply with locations without butterflies, where exposed soil often exceeds 20% and shows greater variability over time. The reduced presence of exposed soil in butterfly habitats likely supports the retention of moisture and promotes the growth of vegetation necessary for shelter and food resources, highlighting its ecological significance. The trends in Grass Coverage, presented in Figure 6, further illustrate differences between the two types of locations. In butterfly-supporting habitats, grass coverage remains relatively stable and moderate, with values generally below 15%. Such stability suggests a balanced ecosystem where grass does not dominate or impede other essential vegetation types, such as shrubs and trees. In contrast, locations without butterflies exhibit highly variable grass coverage, with values sometimes exceeding 50%. This variability may reflect environmental disturbances or less competitive vegetation dynamics, both of which are unfavorable for butterfly populations. The most striking findings relate to shrub and tree coverage (Figure 7), where butterfly habitats consistently show high levels of coverage, frequently exceeding 80%. This dense and stable coverage is in stark contrast to locations without butterflies, where shrub and tree coverage is significantly lower, often ranging between 30% and 60%. Furthermore, the higher fluctuations observed in non-butterfly locations suggest less stable ecological conditions. The strong association between butterfly presence and dense shrub and tree coverage underscores the importance of this vegetation type in providing essential resources, such as nectar, shelter, and microclimatic stability. Figure 5: Temporal trends in exposed soil cover (%) across six study locations (2015–2024), grouped by butterfly presence. Figure 6: Temporal trends in grass cover (%) across six study locations (2015–2024), grouped by butterfly presence. Overall, the trends reveal that butterfly habitats are characterized by a combination of low exposed soil, moderate grass coverage, and high, stable shrub and tree density. These findings suggest that maintaining such vegetation structures is crucial for the conservation of butterfly populations. The stability of these conditions appears to be particularly important, as it minimizes ecological stressors and ensures the availability of critical resources. To assess whether the observed differences in vegetation structure between sites with and without _P.