WEST KIMBERLEY PLACE REPORT - Department of Sustainability ...

new genera (see more detail under vine thickets below). All snail species appear to be
endemic to the islands (i.e. do not occur on the mainland) and each island tends to
have a unique suite of species (Köhler 2009). These discoveries lend support to the
argument that speciation is occurring within a region of stable, long term evolutionary
refugia.
Related to discussions of island refugia, a nominator claimed that there were
genetically isolated populations of dingos (Canis lupus dingo) on a number of the
islands of the Bonaparte Archipelago. It was claimed that due to their isolation, like
Queensland's Fraser Island dingos, the Kimberley Island dingo population best
represents an 'outstanding' example of the original genotype and phenotype ('ancestral
dingo') that first arrived in Australia approximately 4,000–6,000 BP (DEWHA 2008).
Recent survey work found evidence of dingos on Uwins Island (DEC survey) and the
eastern most of the Purrungku Islands (How et al. 2007), however their presence was
not confirmed on another four islands for which there are historical records of dingo
scats or tracks. This raises doubts over the sustained dingo occupation of the
Kimberley Islands (Russell Palmer pers. comm. November 2009).
Island populations of critical weight range species such as the northern quoll
(Dasyurus hallucatus), the golden bandicoot (Isoodon auratus), the scaly-tailed
possum (Wyulda squamicaudata) and the golden-backed tree rat (Mesembriomys
macrurus) are of particular importance due to their decline on the mainland caused by
an array of human-induced threatening processes. Populations of these species
recorded from the first island surveys in the early 1970s were all found to be robust
when these islands were resurveyed in 2007–09. This provides support for the
argument that the Kimberley islands are playing an increasingly important role as
places of human induced refugia.
Savanna woodland, typically composed of eucalypt and bloodwood canopy above a
grassy understorey, dominates most parts of the Kimberley and northern Australia.
ANHAT analysis shows that moving away from the north coast and islands into this
drier savanna country coincides with lower endemism and richness values. The
significance of savanna communities, as part of the Kimberley regional flora, is
discussed under the Wealth of the Land and Sea section.
The significance of areas such as Yampi Peninsula and the country to the east of
Drysdale River National Park are likely to be underestimated due to limited historic
biological surveying. However the national strength of the ANHAT richness and
endemism values for the Mitchell Plateau is real and correlates closely with the
locally high rainfall (Kenneally et al. 1991). This trend is consistent with other
northern Australian biodiversity hotspots, such as the Top End and the orographically
rain fed mountains of Cape York and the Wet Tropics (Abrahams 1995; Bowman
1996; Woinarski et al. 2006).
To summarise the above findings, biodiversity analysis using the Australian
Government's Australian Natural Heritage Assessment Tool (ANHAT), supported by
the Australian Heritage Council’s expert opinion, has shown the northern Kimberley
coast and islands, the Kimberley Plateau and the west Kimberley Devonian reefs are
nationally significant for species richness and endemism for many plant, mammal,
reptile, frog and invertebrate groups. Island populations of critical weight range
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