AUSTRALASIAN BIOGEOGRAPHY

Austral Biotic Atlas Project www.bioatlas.info

The Austral Bioregionalisation Atlas (ABA) aims to be a repository of all names and maps used to describe and depict phytogeographical, zoogeographical, freshwater zoogeographical and marine areas within the Austral region (see Ebach 2012). Each area has a dedicated page that contains synonymies, a diagnosis, description, type-locality and a map of the area. Area names are synonymised according to the International Code of Area Nomenclature (ICAN) in order to distinguish it from other uses of the same term. For further news on further developments and updates, visit the ABA blog.

Presently the ABA is limited to Australia and is taken from Ebach et al. (2013a) Zootaxa 3619: 315-342 [open access]. Corrigendum (Ebach et al. 2013b) Zootaxa 3652: 299-300 [open access].

The ABA is funded by the University of New South Wales, Australia and supported under the Australian Research Council's ‘Future Fellow’ funding scheme (project number FT0992002).

` Zoogeographical Regions of Australia


Discovering Biotic Breaks

Mammal and plant turnover

Presently I am working with Joe Miller (CSIRO), Carlos Gonzalez-Orozco (University of Canberra) and Shawn Laffan (UNSW) on several exciting projects that attempt to qualify the regions proposed in the ABA.

I am also co-supervising PhD student Giovanni di Virgilio with Shawn Laffan (UNSW) on a project using fine scale quantification of floral and faunal breaks in order to discover biotic breaks. So far two papers have appeared:

"We introduce a method to quantify shared breaks in aggregate biotic distributions and their relationships to geographic variables. The method is based on quantification of distributional taxic and abiotic data that can be applied over multiple spatial scales. We aim to show biogeographic breaks and varying transition zones at a fine level of detail (5-km resolution) and develop an approach to assess existing bioregionalization schemes" (di Virgilio et al. 2012).

"We quantify spatial turnover in communities of 1939 plant and 59 mammal species at 2.5 km resolution across a topographically heterogeneous region in south-eastern Australia to identify distributional breaks and low turnover zones where multiple species distributions overlap. Environmental turnover is measured to determine how climate, topography and geology influence biotic turnover differently across a variety of biogeographic breaks and overlaps. We identify the genera driving turnover and confirm the versatility of this approach across spatial scales and locations" (di Virgilio et al. 2013).


Temporal Geobiotic Mapping (with Giovanni di Virgilio and Shawn Laffan, UNSW)

Temporal Geobiotic Mapping Biostrata of geobiota A1–A3.is a conceptual mapping technique toward visualising geobiotic areas in cross-sec- tion. Geobiota are defined by taxic assemblages (i.e., biota) and their defining abiotic breaks, which are mapped in cross-section to reveal past and future biotic boundaries. We term this conceptual approach Temporal Geobiotic Mapping (TGM) and offer it as a conceptual approach for biogeography.

TGM is based on geological cross-sectioning, which creates maps based on the distribution of biota and known abiotic factors that drive their distribution, such as climate, topography, soil chemistry and underlying geology. However, the availability of abiotic data is limited for many areas. Unlike other approaches, TGM can be used when there is minimal data available.

Biotic areas are best represented visually as maps, which can show transgressions and regressions of biota and abiota over time. Using such maps, a biogeographer can directly compare animal and plant distributions with features in the abiotic environment and may identify significant geographical barriers or pathways that explain biotic distributions. TGM is published in Ebach et al. (2013).


Reconstructing the biotic history of Australasia

LisBeth LogoAustralasian biotic history will be investigated will all possible data available (area classifications, morphological and molecular derived phylogenies) when finding biotic relationships as well as using geological and geographical data when predicting former and future biotic barriers.

Paralogy-free Subtree Analysis (PfSA) and Area Cladistics will be used to reconstruct the area relationships and geographical positions of biotic areas through time. The phylogenies will be assessed using the subtree analysis method implemented by Python based software program LisBeth (Ducasse et al. 2009). The software has the capability to run extremely large datasets quickly and efficiently and provide an overview of a plethora of subtree values. The PfSA method has successfully recovered biotic relationships in both botanical, zoological and palaeobiological analyses. The recovered patterns will be compared to innovative area definitions and delineations within the ABA.