Graphical exploration of biodiversity

Biodiversity is the variety of all life forms, and comprises the different plants, animals and microorganisms, their genes and the ecosystems of which they are a part. Questions relating to biodiversity are becoming increasingly important to international Antarctic research. Biodiversity research is a key component of the Australian Antarctic program's science strategy for 2004/05-2008/09.

Graphical link browser
The AADC is developing tools for the exploration and analysis of biodiversity data. One of these tools is a graphical link browser. Briefly, each of the species in a biodiversity data set forms a node in a graph. An edge between two nodes indicates some sort of link between the two species. In the examples given here, the data are shipboard observations, so species are linked if they have been co-sighted (that is, observed in close proximity to one another). The resulting graph gives indications of the species community structure.

The link browser concept is demonstrated below using observations of seabirds made from ships in the Prydz Bay region of East Antarctica.

Community structure graph derived from observations of seabirds in Prydz Bay, Antarctica. An interactive version (requires Java) of this graph is also available.

The structure of the Prydz Bay community from the above graph matches that previously found using standard ecological analysis methods. There is a group of species (including Adélie and emperor penguins, snow and Antarctic petrels, and others) that breed on the Antarctic continent, and a group of migratory birds (including albatrosses and shearwaters) that visit Prydz Bay to feed during the summer.

The international nature of research in Antarctica, coupled with the global scope of the research questions being addressed, often means that research data need to be drawn from different institutions and research programs. The ability to share this data is a crucial part of successful Antarctic research. The link browser tool is able to interact with the Global Biodiversity Information Facility (GBIF) (a recent web-based initiative for sharing biodiversity data) which means that we can apply this tool to biodiversity data sets from other institutions. Below we show the equivalent graph for the north Atlantic region, using data from the PIROP shipboard survey database from Environment Canada.

Community structure graph derived from observations of seabirds and whales in the north Atlantic. An interactive version (requires Java) of this graph is also available.

There are some clear differences between the two graphs:

• Number of species: the north Atlantic has many more species than does Prydz Bay. This is due both to the higher productivity of the north Atlantic (higher productivity means more food available) and also to the greater range of environmental conditions in the north Atlantic environment (from cool temperate to Arctic).
• Bird types: the Antarctic graph shows a greater proportion of oceanic birds such as albatrosses, whereas the north Atlantic community is largely near-shore feeders such as terns and gulls.
• Same species: some species appear in both graphs. Wilson's storm petrels breed on the Antarctic continent, but also migrate to the northern hemisphere during the austral winter. Thus, the individuals observed in the north Atlantic may also have been observed in the Antarctic. Other species, such as sooty shearwaters, have distinct northern and southern hemisphere populations.