The Australian Fossil Mammal Sites are a
natural world heritage site comprising two areas- the
Riversleigh World Heritage Site and Naracoorte Caves
National Park. The Riversleigh World Heritage Site is part
of the Boodjamulla (Lawn Hill) National Park, located
to the northwest of Mount Isa. This site represents an
extraordinary assemblage of mammals of the period
from the Oligocene to the Miocene (10-30 million years
ago).
Only one section of the park is open to tourists, the Riversleigh D-site. Naracoorte Caves National Park is situated south of Naracoorte, in South Australia. The caves were created by geological developments over a long period. The site is visited by a large number of visitors. The impact of heavy tourism in the fragile ecosystem needs to be understood.
In 1994, the UNESCO World Heritage Committee inscribed the Riversleigh portion of Boodjamulla (Lawn Hill) National Park and Naracoorte Caves on the World Heritage List after a careful evaluation of the values of the two areas. They have been jointly inscribed as the Australian Fossil Mammal Sites World Heritage Area. Both the sites are enlisted among the world's ten greatest fossil sites (UNESCO whc.unesco.org 2009). Geographically, Riversleigh and Naracoorte National Park are located over 2000 km apart, in two Australian states, Queensland and South Australia (King & Bourne 2009).
The Riversleigh fossil site, with an extent of 10,000 ha, is located 250 km northwest of Mount Isa and 200 km south of the Gulf of Carpentaria, in the northwestern part of Queensland. It forms part of the southernmost segment of the 282,000-ha Boodjamulla (Lawn Hill) National Park (Queensland Parks & Wildlife Service 2002).
Palaeontological evidence indicates that the fossil deposits of Riversleigh are 10-30 million years old. A total of 250 discrete localities have been identified at the site (Australian Government 2002a; Australian Museum, 2011). A particular location called the Riversleigh D-Site is one of the first fossil deposits to be discovered at Riversleigh. It was formed 24 million years ago, and it is the only location open to tourists (King & Bourne 2009). The Waanyi, the indigenous people, have been living in the region for a thousand years, and this has added the cultural values of the Riversleigh World Heritage Site (Breakey 2012). The Waanyi people are the traditional owners who have been involved in the land management of the Riversleigh region .
They regard the Riversleigh region as a sacred area and call it the Rainbow Serpent Country (Breakey 2012). The Naracoorte part of this World Heritage Site is located within the Naracoorte Caves National Park, about 11 km southeast of the Naracoorte township, in southeastern South Australia (Breakey 2012). It encompasses an area of 600 ha. There are 26 caves within the park. They contain the fossil remains of tens of thousands of vertebrate animals. These remains constitute one of the richest deposits of Pleistocene vertebrate fossils in the world (Reed & Bourne 2000). The faunal biodiversity of this deposit is remarkable, with 118 amphibian, reptile, bird and mammal species having been discovered . The caves of the Narcoorte World Heritage Area document faunal changes over several ice ages. They highlight the impacts of both climate change and humankind on Australia's mammals from at least 500,000 years ago . However, the site is best known for its megafauna fossils, including fossils of a giant Tasmanian devil, giant kangaroos, a marsupial lion, a giant echidna and a giant python (South Australian Department of Environment and Heritage 2001)
These fossil deposits are outstanding examples
representing major stages of earth's history, including
the record of life. Riversleigh provides exceptional, and
in many cases unique, mammal assemblages from the
Oligocene to Miocene, spanning from 10-30 million years
ago. These assemblages document changes in habitat
from humid, lowland rainforest to dry eucalypt forests
and woodlands, and provide the first fossil record for
many distinctive groups of living mammals such as
the marsupial moles and feather-tailed possums.
The assemblages recovered from the caves at Naracoorte Victoria Fossil Cave preserve an outstanding record of more recent terrestrial vertebrate life. These open a window into a significant period of earth's history from the mid-Pleistocene to present (530,000 years ago to today), a period characterised by great climatic changes
Both sites provide complementary evidence of key stages in the evolution of the fauna of one of the world's most isolated continents. The history of mammal lineages in modern Australia can be traced through these fossil deposits and, as a consequence, there is a better understanding of the conservation status of living mammals and their communities.
The Riversleigh World Heritage Site is primarily owned and managed by Queensland Parks and Wildlife Service as well as the Australian government (Queensland Government Environmental Protection Agency 2004).
Studies of the diverse Riversleigh fossils, which are remarkably well preserved, has led to an understanding of the mammal assemblages that existed during the time of greatest biological diversity in Australia's evolutionary history. Presumably, it is sufficiently comprehensive for us to understand the environmental conditions in which the animals lived (Luly & Valentine 1998).
Much interest has been created in this unique heritage site among tourists.
Travellers are motivated to visit this site to experience ecological history (Breakey
2012). However, as only one section of the Riversleigh fossil site is open to
tourists because the number of staff members is insufficient to cater to the
large number of tourists (Breakey 2012).
Monitoring the number of tourists visiting any heritage site is an essential element of its management (Pitts & Smith 1993; Eagles et al. 2002; Newsome et al. 2002; Wardell & Moore 2004). It involves systematic and periodic collection and analysis of information relating to both the natural environment and visitors over time (Eagles et al. 2002; Newsome et al. 2002). Several visitor monitoring studies are being conducted at the Australian Fossil Mammal Sites as they are believed to have an unstructured plan regarding this issue (King & Bourne 2009).
The values of the Australian Fossil Mammal Sites are protected through effective management plans. According to an IUCN assessment, regular site inspections, flood control measures (in Naracoorte Caves National Park) and a documented burning programme designed to mitigate any negative effects associated with wildfires are some of the measures that have been executed by the authorities (IUCN 2020). There have been wildfires at Boodjamulla (Lawn Hill) National Park, including the Riversleigh site. Although these may have an impact on the biodiversity, they are not considered a major threat to the World Heritage values of the area. With an approved fire strategy, the risk of large-scale fires is minimised (State Party of Australia 2003). IUCN World Conservation Outlook assessed the site as "good" in the 2020 assessment cycle.
