The Area boundaries have been defined primarily on the basis of the hydrological catchments in the McMurdo Dry Valleys, including all of the ice-free ground and adjacent areas within these catchments, all of the Convoy Range, and the catchment of the Alph River. Starting at the northwest corner and moving counter-clockwise, the boundary is delineated by the following features: the northwest tip of Allan Nunatak (76.7167 S, 159.6667 E), Carapace Nunatak (76.8833 S, 159.4 E), Mt. DeWitt (77.2 S, 159.8333 E), the western edge of Horseshoe Mountain (77.5667 S, 159.95 E), Depot Nunatak (77.75 S, 160.0667 E), the southernmost peak of the Lashly Mountains (77.9606 S, 159.5603 E), Mt. Kempe (78.3167 S, 162.7167 E), the Pyramid (78.35 S, 163.5 E), the east side of Heald Island (78.25 S, 163.8167 E), De Master Point (off the eastern end of Marshall Valley, 78.0792 S 164.4131 E), north along the coast following the mean low tide level to the east side of Tripp Island (76.6333 S, 162.7 E), the southern edge of Fry Glacier (76.6333 S, 162.3 E), and, again the northwest tip of the Allan Nunatak (76.7167 S, 159.6667 E).
The McMurdo Dry Valleys are characterized as the largest relatively ice-free region in Antarctica with approximately thirty percent of the ground surface largely free of snow and ice. The region encompasses a cold desert ecosystem, whose climate is not only cold and extremely arid (in the Wright Valley the mean annual temperature is -19.8°C and annual precipitation is less than 100 mm water equivalent), but also windy. The landscape of the Area contains glaciers, mountain ranges, ice-covered lakes, meltwater streams, arid patterned soils and permafrost, sand dunes, and interconnected watershed systems. These watersheds have a regional influence on the McMurdo Sound marine ecosystem. The Area’s location, where large-scale seasonal shifts in the water phase occur, is of great importance to the study of climate change. Through shifts in the ice-water balance over time, resulting in contraction and expansion of hydrological features and the accumulations of trace gases in ancient snow, the McMurdo Dry Valley terrain also contains records of past climate change. The extreme climate of the region serves as an important analogue for the conditions of ancient Earth and contemporary Mars, where such climate may have dominated the evolution of landscape and biota.
The Area is characterized by unique ecosystems of low biodiversity and reduced food web complexity. However, as the largest ice-free region in Antarctica, the McMurdo Dry Valleys also contain relatively diverse habitats compared with other ice-free areas. The Area contains unusual microhabitats and biological communities (such as endolithic and Cryoconite systems) as well as special geological features and minerals (for example, salt deposits and desert pavements). Some of these special geological features are of value because they contain an extremely long record of natural events. The long‑term data sets for environmental observations that have been collected in this region are some of the longest in Antarctica. The McMurdo Dry Valleys contain indicators of past and present regional climate change, as well as features that play a role in influencing local climate change.
These scientific values are also of global as well as regional importance. The Area is a valuable resource for understanding landscape processes and the stability of Antarctic ice sheets. The McMurdo Dry Valleys contain unique surface deposits including glacially deposited and modified sediments, sand dunes, desert pavement, glacio-lacustrine sediments, and marine fjord sediments containing valuable records of planetary change. The soil, rock, water, and ice environments and their associated biota are of scientific value as model ecosystems that allow deep insights into natural processes operating throughout the biosphere. Finally, the species that reside in the McMurdo Dry Valleys provide a biological resource for understanding adaptation to extreme environments, and are true end members of ecological continua.
The McMurdo Dry Valleys are also valued for their wilderness quality. They represent a nearly pristine environment largely undisturbed and uncontaminated by humans. The dramatic landscape, composed of high ridges and sweeping valleys, and contrasts of ice-free and glacier-covered terrain creates unique vistas with high aesthetic value.
Activities conducted in the area include a variety of scientific research, operations in support of science, media, arts, education and other official national programme visitors; and tourism. A Long Term Ecological Research site has been established in the Taylor Valley.
This ASMA is proposed on the grounds that Cape Denison is a site of historic, archaeological, social and aesthetic values.
Historic value
Antarctica’s ‘heroic age’ was a period of great human adventure and discovery. Cape Denison, Commonwealth Bay provides the setting for the buildings, structures and relics of the Main Base of the Australasian Antarctic Expedition (AAE) of 1911–14, led by Dr Douglas Mawson.
The prime focus of Mawson’s was scientific research. Nevertheless, the expedition also had an exploratory agenda, with the aim of charting the entire Antarctic coastline immediately south of Australia. For this purpose at least five sledging expeditions were undertaken from Cape Denison from spring 1912, including the infamous Far-Eastern Sledging Party during which expeditioners Belgrave Ninnis and Xavier Mertz perished and Mawson himself barely survived. Overall, more than 6 500 km of coastline and hinterland was explored by sledging parties of the Expedition.
Cape Denison contains numerous relics relating to the work of Mawson’s expedition, including Mawson’s Huts and other significant and relatively untouched artefacts from the ‘heroic age’. While the majority is concentrated in the westernmost valley and its immediate surrounds, the historical boundaries of the Main Base extend further. Artefacts and other evidence of occupation, such as food caches, extend across the entire Cape, forming a rich resource of material available for research and interpretation, and potentially yielding scientific data and information about aspects of expeditioner life not included in official written accounts.
Aesthetic values
This ASMA is designated to preserve not only the artefacts remaining in situ but also the cultural landscape of Cape Denison in which Mawson and his men lived and worked. Cape Denison is characterised by its almost incessant blizzard conditions, which severely limit access to the region and activities at the site. System and katabatic winds pour down the plateau and funnel through the Cape’s valleys; blasting the hut with gusts that in May 1912 reached 322 km/h. (The average wind speed for the month was 98 km/h). Cape Denison is not only the windiest place in Antarctica, but also the windiest place on Earth at sea level. The site thus provides the physical and symbolic context of the extreme isolation and harsh conditions endured by the expedition members and, by association, all other ‘heroic age’ researchers and explorers. In designating the entire area as an ASMA, Cape Denison’s unique ‘sense of place’ is protected, with Mawson’s Huts and Boat Harbour as the focus of the visual catchment. Mawson’s Huts themselves are provided with additional protection in ASPA 162.
Educational values
Cape Denison’s wildlife and undisturbed artefacts, framed against the dramatic backdrop of the Antarctic Plateau, represent significant educational values. The Area’s isolation and extreme weather provide visitors with a unique insight into the conditions endured by ‘heroic age’ researchers and explorers, and a chance to form a deeper appreciation of their achievements.
Environmental values
The paucity of relatively ice-free areas in the immediate region means that Cape Denison represents an important assemblage of life forms. The closest ice-free areas of equal or greater size to Cape Denison are approximately 20 km to the east of Cape Denison (from the centroid of the ASMA), and approximately 60 km to the west respectively. A haul-out site for Weddell, leopard and elephant seals, the Cape is also an important breeding area for Adélie penguins, Wilson’s storm-petrels, snow petrels and south polar skuas.
Flora at Cape Denison is represented by 13 lichen species distributed on boulders and other moraines throughout the peninsula. No bryophytes are evident. The lichens’ distribution on rocks, which are subject to different patterns of snow ablation, makes them vulnerable to trampling and other interference by visitors, however infrequent visitation may be.
Cape Denison has 13 small lakes. These are associated with glacial action, are a permanent feature, and are frozen over for most of the year. Since such lakes are also susceptible to physical, chemical and biological modification within their catchment boundaries, a catchment-based approach to the management of human activities is required.
Scientific values
Mawson, a geologist, planned his expedition in order to examine the theories about continental connection and the processes of glaciation and climate. He also sought to study the South Magnetic Pole and magnetic charting for navigational purposes; to conduct biological studies, including the identification of new species; and to establish a weather station.
Cape Denison provides opportunities to repeat Mawson’s experiments and conduct further research into magnetism, meteorology, biology, and other sciences. For example, although Antarctic lakes are generally recognised as valuable due to their relatively simple natural ecosystems, the lakes at Cape Denison have neither been sampled nor their biota studied. There are also numerous non-marine algae present; however, no surveys have been undertaken.
The records from Mawson’s expedition provide a dataset against which the results of modern research may be compared, and the site’s isolation lends it considerable value for future use as a reference site for other areas that experience a greater level of human activities.