Shark Bay (578)

One of the superlative natural phenomena present in this property is its stromatolites, which represent the oldest form of life on Earth and are comparable to living fossils. Shark Bay isalso one of the few marine areas in the world dominated by carbonates not associated with reef-building corals. This has led to the development of the Wooramel Seagrass Bank within Shark Bay, one of the largest seagrass meadows in the world with the most seagrass species recorded from one area. These values are supplemented by marine fauna such as dugong, dolphins, sharks, rays, turtles and fish, which occur in great numbers. The hydrologic structure of Shark Bay, altered by the formation of the Faure Sill and a high evaporation, has produced a basin where marine waters are hypersaline (almost twice that of seawater) and contributed to extensive beaches consisting entirely of shells. The profusion of peninsulas, islands and bays create a diversity of landscapes and exceptional coastal scenery.

Shark Bay contains, in the hypersaline Hamelin Pool, the most diverse and abundant examples of stromatolites (hard, dome-shaped structures formed by microbial mats) in the world. Analogous structures dominated marine ecosystems on Earth for more than 3,000 million years. The stromatolites of Hamelin Pool were the first modern, living examples to be recognised that have a morphological diversity and abundance comparable to those that inhabited Proterozoic seas. As such, they are one of the world's best examples of a living analogue for the study of the nature and evolution of the earth's biosphere up until the early Cambrian. The Wooramel Seagrass Bank is also of great geological interest due to the extensive deposit of limestone sands associated with the bank, formed by the precipitation of calcium carbonate from hypersaline waters.

Shark Bay provides outstanding examples of processes of biological and geomorphic evolution taking place in a largely unmodified environment. These include the evolution of the Bay's hydrological system, the hypersaline environment of Hamelin Pool and the biological processes of ongoing speciation, succession and the creation of refugia. One of the exceptional features of Shark Bay is the steep gradient in salinities, creating three biotic zones that have a marked effect on the distribution and abundance of marine organisms. Hypersaline conditions in Hamelin Pool have led to the development of a number of significant geological and biological features including the 'living fossil' stromatolites. The unusual features of Shark Bay have also created the Wooramel Seagrass Bank. Covering 103,000 ha, it is the largest structure of its type in the world. Seagrasses are aquatic flowering plants that form meadows in nearshore brackish or marine waters in temperate and tropical regions, producing one of the world's most productive aquatic ecosystems. Australia has one of the highest diversity of seagrasses globally, with 12 species occurring in the Bay

Shark Bay is a refuge for many globally threatened species of plants and animals. The property is located at the transition zone between two of Western Australia's main botanical provinces, the arid Eremaean, dominated by Acacia species and the temperate South West, dominated by Eucalyptus species, and thus contains a mixture of two biotas, many at the limit of their southern or northern range. The property contains either the only or major populations of five globally threatened mammals, including the Burrowing Bettong (now classified as Near Threatened), Rufous Hare Wallaby, Banded Hare Wallaby, the Shark Bay Mouse and the Western Barred Bandicoot. A number of globally threatened plant and reptile species also occur in the terrestrial part of the property. Shark Bay's sheltered coves and lush seagrass beds are a haven for marine species, including Green Turtle and Loggerhead Turtle (both Endangered, and the property provides one of Australia's most important nesting areas for this second species). Shark Bay is one of the world's most significant and secure strongholds for the protection of Dugong, with a population of around 11,000. Increasing numbers of Humpback Whales and Southern Right Whales use Shark Bay as a migratory staging post, and a famous population of Bottlenose Dolphin lives in the Bay. Large numbers of sharks and rays are readily observed, including the Manta Ray which is now considered globally threatened.

The Australian Government agency that is responsible for the management of the property is the Department of Biodiversity, Conservation. The site's advisory committee is the body that provides conservation- and management-related advice to the State and Commonwealth governments. The Australian Government and the Western Australian Government have entered into an agreement to manage as per Australia's obligations under the World Heritage Convention. According to the IUCN World Heritage Outlook Report 2020, the conservation outlook of the site assessed "Good with some concerns". The site does not face significant threats arising from outside the boundary due to the inaccessibility and appropriateness of its boundaries (Claudino 2018). The impacts of human activities include trampling of sensitive environments, hardening of shorelines and 4WD traffic over soft sediments (IUCN world heritage outlook 2020). Potential threats such as fires (Cowell 2013) and the introduction of invasive species might affect the biodiversity of the park severely, and so proper monitoring and management are needed (Fourqurean et al. 2012). Climate change is the major threat to the region, and it is expected to intensify in the future. Climate change can impact the complex ecosystems of the site. The region might suffer from severe impacts of climate change such as desertification and acidification, considering its semi-arid conditions. The rising sea level can cause more erosion of the coastline. The ecological characteristics of the environment change as the hypersaline environment can increase the amount of salt. The State of the Conservation Report, 2000 recognizes that there are some potential threats in the property such as the production of salt and prospecting for and extraction of mineral and petroleum resources, which will eventually impact the values of the park. Invasive alien species pose a serious threat in the region. The pressure arising due to the fishing has been effectively managed. The sea grasses, found in abundance in this region, are extremely vulnerable to climate change. Once lost, they can regenerate only very slowly. Sea grasses hold the largest stock of organic carbon stock and their preservation becomes crucial in the global context (Arias et al. 2018).