Table 1.
Parameters used for training the sampling points.
| Predictor | Parameter | Data source | Attributes (classes/features) |
Area (km2) |
Share of the total area (%) |
|---|---|---|---|---|---|
| Geology | Lithological structure | Geological Map of Romania (1:200,000) | Gravel | 1608.8 | 23.6 |
| Clays | 1201.3 | 17.6 | |||
| Sands | 1161 | 17 | |||
| Conglomerates | 903.5 | 13.3 | |||
| Flysch | 438 | 6.4 | |||
| Sandstone | 400.1 | 5.9 | |||
| Chalk–limestone | 292.9 | 4.3 | |||
| Loess | 296.4 | 4.3 | |||
| Marl | 286.5 | 4.2 | |||
| Breccias | 126.5 | 1.9 | |||
| Shale rock | 92.9 | 1.4 | |||
| Diapir deposits | 7.2 | 0.1 | |||
| Morphometry |
Altitude [m] |
Digital Elevation Model108 | 0–300 | 1388.3 | 20.3 |
| 300–500 | 3240.4 | 47.3 | |||
| 500–800 | 2110.7 | 30.8 | |||
| 800–1205 | 108.8 | 1.6 | |||
| Aspect | Flat | 16.5 | 0.2 | ||
| North | 623.8 | 9.1 | |||
| North-East | 888.3 | 13 | |||
| East | 1055.9 | 15.5 | |||
| South-East | 1020.4 | 15 | |||
| South | 924.6 | 13.6 | |||
| South West | 901.9 | 13.2 | |||
| West | 768.4 | 11.3 | |||
| North West | 614 | 9 | |||
|
Slope [%] |
< 5 | 1473 | 21.6 | ||
| 5–10 | 2268.7 | 33.3 | |||
| 10–15 | 1986.6 | 29.1 | |||
| 15–25 | 1038.7 | 15.3 | |||
| > 25 | 48.9 | 0.7 | |||
| Plan curvature | < − 0.5 | 74 | 1.1 | ||
| − 1 | 6646.1 | 97.5 | |||
| > 0.5 | 95.8 | 1.4 | |||
| Profile curvature | < − 0.5 | 68.6 | 1 | ||
| − 1 | 6670.4 | 97.9 | |||
| > 0.5 | 76.8 | 1.1 | |||
| Total curvature | < − 0.5 | 265.7 | 3.9 | ||
| − 1 | 6258.7 | 91.8 | |||
| > 0.5 | 291.4 | 4.3 | |||
|
Topographic Positioning Index |
Large valleys | 756.1 | 11 | ||
| Hill top | 967.2 | 14.1 | |||
| Mid slope | 640.6 | 9.4 | |||
| Torrential valleys | 889.2 | 13 | |||
| Plain or hil base | 3594.8 | 52.5 | |||
|
Distance to streams [m] |
0–500 | 3971.9 | 59.4 | ||
| 500–1000 | 2282.2 | 34.1 | |||
| 1000–1500 | 421.1 | 6.3 | |||
| 1500–2000 | 9.35 | 0.1 | |||
| Soil | Texture | Soil Map of Romania (1:200,000) | Clay loam | 5576.7 | 81.8 |
| Clay | 1165.3 | 17.1 | |||
| Silty clay loam | 42.9 | 0.6 | |||
| Loam | 21 | 0.3 | |||
| Silty Clay | 10 | 0.1 | |||
| Land use |
Tree cover density [%] |
Copernicus Land Monitoring service; URL: |
< 0.99 | 2499 | 36.7 |
| 1–20 | 0.68 | 0.01 | |||
| 21–40 | 8.05 | 0.1 | |||
| 41–60 | 79.5 | 1.2 | |||
| 61–80 | 993 | 14.6 | |||
| > 80 | 3232.7 | 47.4 | |||
|
GRAVPI [%] |
Copernicus Land Monitoring service; URL: https://land.copernicus.eu/looking-for-national-products | < 0.99 | 5913.2 | 86.8 | |
| 1–20 | 47 | 0.7 | |||
| 21–40 | 111.8 | 1.6 | |||
| 41–60 | 247.9 | 3.6 | |||
| 61–80 | 258.3 | 3.8 | |||
| > 80 | 237.1 | 3.5 | |||
| LULC | Land Use Land Cover (2018); URL: https://land.copernicus.eu/pan-european/corine-land-cover/clc2018 | Forest and trees | 3212.6 | 47.1 | |
| Pastures and natural grasslands | 1400.4 | 20.5 | |||
| Agricultural land | 1226.7 | 18 | |||
| Built | 481.8 | 7.1 | |||
| Vineyards and trees | 392.6 | 5.8 | |||
| Marshes and water courses | 78.3 | 1.1 | |||
| Bare land | 22.2 | 0.3 | |||
| Green urban areas | 0.4 | 0.01 | |||
| Road and rail networks and associated land | 0.3 | 0.01 | |||
| Hydrological | Hydrologic soil groups | Derived from Soil Map of Romania (1:200,000) | A | 963 | 14.1 |
| B | 2166.8 | 31.8 | |||
| C | 1657.1 | 24.3 | |||
| D | 2028.7 | 29.8 | |||
| Curve number | Derived from Soil Map of Romania (1:200,000) and LULC (2018) | > 34 | 65.8 | 0.99 | |
| 34–50 | 753.6 | 11.3 | |||
| 51–70 | 1848.7 | 27.8 | |||
| 70–85 | 2767.9 | 41.6 | |||
| 85–95 | 1214.4 | 18.3 | |||
| Rainfall |
Erosivity [(MJ mm)/(ha h yr)] |
European Soil Data Center; URL: https://esdac.jrc.ec.europa.eu/resource-type/datasets | 600–700 | 2.4 | 0.03 |
| 700–800 | 1998.1 | 29.1 | |||
| 800–900 | 4603.1 | 67.1 | |||
| 900–1000 | 255.4 | 3.7 | |||
| Small ruminants |
Density [heads/ha] |
General Agricultural Census118; URL: http://www.rga2010.djsct.ro/inceput.php?cod=58&codj=10) Land fund area by usage, counties and localities; URL: http://statistici.insse.ro:8077/tempo-online/#/pages/tables/insse-table) |
< 1 | 771 | 11.3 |
| 1–2 | 1503.1 | 22.1 | |||
| 2–3 | 1710.7 | 25.1 | |||
| 3–5 | 1576.3 | 23.1 | |||
| > 5 | 1254.6 | 18.4 |
GRAVPI grassland vegetation probability index, LULC land use land cover.