Guiana Shield is equally rich and 13,367 species of vascular plants have been found, approximately 40% of which is considered endemic. The shield is overlain by the largest expanse of tropical forest on any Precambrian shield area in the world. Guianan rain forest is similar in nature to Amazonian rain forest and known protected areas include the Iwokrama Forest of central Guyana, Kaieteur, Kanuku National Park of southern Guyana, the UNESCO World Heritage Site Central Suriname Nature Reserve of Suriname, the Guiana Amazonian Park in French Guiana and the Tumucumaque National Park in the Amapá State of Brazil. In Venezuela the forests
Suriname the Atlantic coast. The southernmost borders with French Guiana and Guyana are disputed by these countries along the Marowijne and Corantijn rivers, respectively, while a part of the disputed maritime boundary with Guyana was arbitrated by a tribunal convened under the rules set out in of the United Nations Convention on the Law of the Sea on 20 September 2007. Lying 2 to 5 degrees north of the equator, Suriname has a very hot and wet tropical climate, and temperatures do not vary much throughout the year. Average relative humidity is between 80% and 90%. Its average temperature ranges from