## 2 Materials and Methods
### Methods  
The workflow for the evaluation of the ecosystem's condition (Figure 2) consisted in three phases. The first phase included state-of-the-art methods for identifying the potential pressures on each ecosystem; searching for ecosystem sustainability threshold definitions; identification of data sets available for the calculation of degradation indicators; data processing and analysis; validation of the applied method. For each ecosystem, a specific assessment methodology was involved. The second phase included correction and adjustment of each indicator used according to the field results; final data processing, field verification and validation. In the final stage, a topological attribute verification was performed. The methodologies for establishing the level of degradation of the analyzed ecosystems included elements that have an impact on their health and sustainability. The determination of the level of degradation and the classes of degradation also took into account the capacity of ecosystems to support and provide ecosystem services in accordance with their basic functions (Supplementary Material). The method describing the forest ecosystem's status was based on the identification of deforested areas using the change detection algorithm between the land use category according to LPIS data [38; 54] and the land use in the reference year of 2000, according to the tree canopy cover from Landsat [37]. The conservation status of forest ecosystems was established based on the VCF MODIS [37] product from 2000 to 2013 and the calculation of the linear trend for each pixel [10]. Forest degradation was analyzed by permanent changes in terms of land cover and land use. These changes reduce ecological integrity and health (SER, 2004) affecting the biodiversity and productivity of forests. The evaluation of the grassland ecosystems was made based on six criteria, each criterion having a specific weight in the final result, Equation (1) [10]. The six criteria refer to the anthropo-zoogenic impact (proximity to localities, proximity to sheepfolds, the total livestock density) [55], stationary conditions (slope) and structural characteristics (invasive species and bare soil/erosions). Each criterion was divided into three classes of values,  
Figure 2: Methodological flow in order to assess the state of ecosystem degradation. and each class received a score corresponding to the ecosystem condition, as follows: 0--natural, 1--semi-degraded, 2--degraded [10]. The identification of invasive species and soil or bare soil erosion was based on machine learning algorithms such as Random Forest (RF) and Support Vector Machine (SVM). The degradation state was assigned according to the value of the degradation index (DI). Thus, DI values between 0 and 30 indicated natural grassland ecosystems, between 35 and 60 they represented semi-degraded and between 65 and 180 degraded grassland ecosystems. \[\text{DI}=(5\times\text{C1})+(20\times\text{C2})+(5\times\text{C3})+(10\times \text{C4})+(50\times\text{C5})+(100\times\text{C6}) \tag{1}\]  
where  
C1 = proximity to localities (>4 km = natural, 2-4 km = semi-degraded, <2 km = degraded);  
C2 = proximity to sheepfolds (>2 km = natural, 0.5-2 km = semi-degraded, <0.5 km = degraded);  
C3 = slope (<15\({}^{\circ}\) = natural, 15\({}^{\circ}\)-30\({}^{\circ}\) = semi-degraded, >30\({}^{\circ}\) = degraded);  
C4 = total livestock density (<\(\pm\)10% = natural, \(\pm\)10-50% = semi-degraded, >\(\pm\)30% = degraded);  
C5 = invasive species (<5% = natural, 5-20% = semi-degraded, >20% = degraded);  
C6 = bare soil/erosions (<5% = natural, 5-20% = semi-degraded, >20% = degraded). Cave ecosystems have been assessed on the basis of the Cave Conservation Index (CCI), which determines the impact of the cave environment and the threats and the vulnerability of the intrinsic characteristics of the caves [56].