Bulgaria's biodiversity, one of the richest in Europe, is conserved in three national parks, 11 nature parks, 10 biosphere reserves and 565 protected areas. Ninety-three of the 233 mammal species of Europe are found in Bulgaria, along with 49% of butterfly and 30% of vascular plant species. Overall, 41,493 plant and animal species are present. Larger mammals with sizable populations include deer (106,323 individuals), wild boars (88,948), jackals (47,293) and foxes (32,326). Partridges number some 328,000 individuals, making them the most widespread gamebird. A third of all nesting birds in Bulgaria can be found in Rila National Park, which also hosts Arctic and alpine species at high altitudes. Flora includes more than 3,800 vascular plant species of which 170 are endemic and 150 are considered endangered. A checklist of larger fungi in Bulgaria by the Institute of Botany identifies more than 1,500 species. More than 35% of the land area is covered by forests.