## 3 Results and Discussions
This highlights a statistically significant high density in the central part of the country due to the numerous natural meadows that are in a medium and high degradation stage due to the anthropogenic pressure on them, the high number of river segments that are in an advanced stage of degradation due to numerous sources of pollution mainly caused by the lack of septic tanks and the inefficient use of chemical fertilizers in agriculture and the south of the Carpathian Mountains, where, along with the declining forest, there are a high number of degraded meadows but also degraded river segments. Statistically significant hotspots were also observed in the Moldavian Plateau and in the north of the Western Plain where there was a high number of degraded lakes and rivers as highlighted by the experts involved in the project on-site (Table 3). \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline \multicolumn{1}{c}{**Degradation.**} & \multicolumn{2}{c}{**Low**} & \multicolumn{2}{c}{**Medium**} & \multicolumn{2}{c}{**High**} \\  & **(1-11)** & & **(11–15)** & & **(15–22)** & \\ \hline
**Relief Units** & **kmp** & **\%** & **kmp** & **\%** & **kmp** & **\%** \\ \hline Eastern Carpathians & 2778.9 & 8.1 & 23,597.6 & 68.7 & 7949.8 & 23.2 \\ Southern Carpathians & 2759.6 & 19.5 & 7120.7 & 50.3 & 4265.8 & 30.2 \\ Banat Mountains & 1747.8 & 25.1 & 4448.4 & 63.8 & 780.3 & 11.2 \\ Sub-Carpathians & 215.5 & 1.3 & 6884.7 & 41.5 & 9473.0 & 57.2 \\ Apuseni Mountains & 275.6 & 2.6 & 5976.2 & 56.1 & 4399.7 & 41.3 \\ Transylvan Depression & 0.0 & 0.0 & 2079.0 & 8.2 & 23,183.6 & 91.8 \\ The Western Hills & 951.6 & 7.4 & 8034.8 & 62.7 & 3825.7 & 29.9 \\ Mehedinti Plateau & 18.1 & 2.3 & 519.5 & 65.1 & 259.7 & 32.6 \\ The Getic Plateau & 1879.4 & 13.6 & 7247.7 & 52.6 & 4654.9 & 33.8 \\ The Plateau of Moldova & 1215.9 & 5.3 & 12,506.0 & 54.8 & 9091.9 & 39.9 \\ Western Camp & 4059.4 & 25.3 & 10,012.9 & 62.3 & 2001.9 & 12.5 \\ The Romanian Plain & 24,664.9 & 50.6 & 22,218.3 & 45.5 & 1903.2 & 3.9 \\ Dobrogea Plateau & 6587.6 & 65.1 & 3424.2 & 33.8 & 105.5 & 1.0 \\ The Danube Delta & 4403.1 & 99.0 & 43.1 & 1.0 & 0.0 & 0.0 \\ \hline \hline \end{tabular}  
* Low, medium and high classes were obtained using a natural-break classification of the density of degraded raster ecosystems presented in Figure 10.  
\end{table} 
Table 3: Classification of relief units in Romania by degradation classes. Figure 10: Density of degraded ecosystems and hotspot analysis. Relative operating characteristics (ROC) analysis was used to determine the accuracy of determining the degradation stage for the six types of ecosystems analyzed. The method provides a curve given by a confusion matrix of binary classification according to four possible outcomes: true positive, true negative, false positive and false negative. The results are derived by comparing results of the model with the ground truth survey (GTS), which are established by through field campaigns carried out in spring, summer and autumn for all 6 types of ecosystems with the help of 35 environmental experts from the project, who aimed to identify the state of ecosystems with an emphasis on their degradation. Statistical analyses were conducted using the SPSS software program. The outcomes are derived by comparing results of the model with the ground truth survey (GTS), approximately 100 points chosen randomly for each type of ecosystem so as to cover all the counties of Romania. The ROC curve is a method that compares true-positive rates against false-positive rates. For each random point, a buffer area of 300 m was analyzed to verify the presence or absence of degradation. Following the analysis of ROC curves for the six types of degraded ecosystems, it can be seen that the models that have a high degree of representativeness for the analyzed problem were those that focused on identifying degraded ecosystems (characterized by a value of the area of under the ROC cure of 0.916) and the model for determining the degraded lakes (characterized by a value of the area under the ROC cure of 0.918) (Figure 11).