Along with a few smaller colonies, which scientists have not surveyed, the butterflies in these major colonies make up the entire breeding stock of monarchs for the eastern United States and Canada.
In 1989, scientists surveyed Vietnam's southern forests to search for evidence of other survivors.
The scientists have surveyed 44.5 km of grottos in this cave so far, but tourists can only penetrate to a distance of 1500 m.
It was first identified in 2003 in Cornwall, UK when scientists were surveying for the presence of Phytophthora ramorum.
Using this approach, scientists from a number of nations have been surveying the waters off Antarctica in every Southern Hemisphere summer since 1978-79, systematically covering the area south of 60 degrees latitude.
The park contains systems of grottoes and caves, of which Vietnamese and British scientists have so far surveyed 20 with a total length of 70 km.
It became extinct before scientists could properly survey the New Zealand avifauna, but possibly as late as 1870 (based on a report of a flightless goose caught in Opotiki.)
During this period, scientists from many countries will be systematically surveying ocean temperatures, salinities and currents.
While scientists have surveyed 44.5 kilometres of passages, tourists are only allowed to explore the first 1500 metres.
When scientists first surveyed this roadless wilderness, they found a serpent eagle that was thought to be extinct, the rare Madagascar red owl, five unknown butterfly species and a new kind of predatory plant.