Six major biodiversity hotspots have been identified across South Australia, including Western Kangaroo Island, Southern Mount Lofty Ranges, Anangu Pitjantjatjara Yankunytjatjara lands, Southern Flinders Ranges, Southern Eyre Peninsula and the Lower South East. However each of these areas is also currently under threat from a combination of habitat fragmentation, invasive species, altered fire regimes and climate change.
The study used a suite of sophisticated species-based metrics to identify six regions with exceptionally high plant diversity (or biodiversity hotspots), including: Western Kangaroo Island; Southern Mount Lofty Ranges; Anangu Pitjantjatjara Yankunytjatjara lands; Southern Flinders Ranges; Southern Eyre Peninsula; Lower South East (Figure 1). Importantly, researchers also looked at how sensitive each site is to climate change, and although all of the state’s ecosystems are expected to be impacted by climate change, the southern Flinders Ranges location is expected to be the most sensitive of the identified biodiversity ‘hotspots’. However, each of the ‘hotspots’ was associated with serious conservation issues, such as habitat fragmentation, weed invasion and/or altered fire regimes. The southern Mount Lofty Ranges contained a high proportion of unique species and overall diversity was high, but has been subjected to the highest levels of disturbance since European settlement. The western side of Kangaroo Island has perhaps the most significant plant biodiversity in South Australia, and was rated as less vulnerable due to higher reservation levels and lower incidences of weed species.
Researchers used statistical programming to convert species distribution data from the State’s Biological Survey program and State Herbarium into maps showing levels of biodiversity. The maps show: Species Richness (estimated numbers of all plant species as well as those of South Australian endemics and conservation-dependent species); Georeferenced Weighted Endemism, Phylogenetic Diversity, Georeferenced Phylogenetic Endemism; Beta Diversity. Estimates were adjusted according to sampling intensity or tested statistically to identify areas with higher biodiversity than expected based on the level of sampling and species richness. Biodiversity maps were overlayed with information on habitat fragmentation, climate sensitivity, fire frequency and weed diversity. A detailed but non-technical overview of many of the metrics used is available via the United Nations Environment Programme.
In conjunction with monitoring of habitat condition, maps of regional biodiversity and threats can inform priorities and strategies for the active management of native vegetation. The context of state-wide ‘hotspots’ and their main threats (whether they be climate change, habitat fragmentation or other) are relevant to the prioritisation and selection of species for pro-active restoration, and for assessing costs and returns associated with offsets, auctions and stewardship programs. From a conservation perspective, the value of the mapping is that it highlights: 1) specific regions within which overall high levels of biodiversity can be maintained; 2) ecological uniqueness and complementarity (e.g. range-restricted biodiversity and endemics), where high scoring sites contain biodiversity that cannot be conserved elsewhere, and; 3) areas of high climate sensitivity (i.e. where the composition of species will change in the future).
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The study was enabled by partnership with the South Australian Government Department of Environment, Water and Natural Resources (DEWNR) and the Terrestrial Ecosystem Research Network (TERN).
All data are available for access and reuse through the Terrestrial Ecosystem Research Network’s AEKOS portal (http://www.aekos.org.au/home). The study also used records from herbarium specimens held at the State Herbarium of South Australia, a database of some 400,000 individual occurrences of 4,500 different plant species, available through Australia’s Virtual Herbarium (http://avh.chah.org.au).
Guerin GR, Biffin E, Baruch Z, Lowe AJ. (2015) Identifying centres of plant biodiversity in South Australia. PLoS ONE DOI 10.1371/journal.pone.0144779