Stream combine to give the park a varied ecology. These ecosystems include bogs, lakes, moorland, mountains, waterways, woodland, parks and gardens. Outcropping rock, cliffs and crags are features of the park. Above , the mountainous sandstone areas support large areas of blanket bog and heath. History Early history Killarney National Park is one of the very few places in Ireland that has been continuously covered by woodland since the end of the most recent glacial period, approximately 10,000 years ago. Humans have lived in the area since at least the Bronze Age, approximately 4,000 years ago. Archaeologists have found evidence that copper mining took place in the Ross Island area during this period, which suggests that the area was of considerable importance to Bronze Age people. The park has many archaeological features, including a well preserved stone circle at Lissivigeen. The woods in the park have been disturbed and cleared at different periods since the Iron Age. This has caused a gradual decline in the diversity of tree species in the park. Some of the most impressive archaeological remains in the park are from the early Christian period. The most important of these features is Inisfallen Abbey, the ruins of a monastic settlement on Inisfallen Island in Lough Leane. It was founded in the 7th century CE by St. Finian the Leper and was occupied until the 14th century. The Annals of Inisfallen, a record of the early history of Ireland as it was known by the monks, was written in the monastery from the 11th to 13th centuries. It is thought that the monastery gave rise to the name Lough Leane, which means "Lake of Learning". Muckross Abbey was founded in 1448 by Observantine Franciscans and is also still standing, despite having been damaged and reconstructed several times when its inhabitants were raided. "Friars Glen" on Mangerton Mountain is customarily said to have been one of the places the monks would flee to when the monastery was attacked. The central feature of Muckross Abbey is a central courtyard that contains a huge yew tree surrounded by a vaulted cloister. It is traditionally said that this tree is as old as Muckross Abbey itself. The abbey was the burial place of local chieftains. In the 17th and 18th centuries the Kerry poets Seafraidh O'Donoghue, Aogán Ó Rathaille, and Eoghan Rua Ó Súilleabháin were buried there. After the Norman invasion of