**1. Introduction**

Conservation obligations are an imperative with the Convention on Biological Diversity calling for the 30% of land and sea areas of signatory countries to be protected by 2030 [1]. Overall, Australia has achieved the Aichi target of 17% of land area conserved [2]. However, conservation based on area alone is insufficient to reduce biodiversity loss, with calls for the consideration of factors, including ecological representation, genetic diversity, connectivity, endangered ecosystems, and species [2–6]. We need to know more about diversity patterns in ecosystems we are aiming to protect in order to inform conservation decisions.

Species richness (SR) is a standard measure of diversity, but incorporating metrics, such as genetic diversity, species composition, centres of endemism, and phylogenetic diversity, are advocated for identifying priority areas of biodiversity now and into the future [7–14]. Species composition patterns can identify areas of distinctiveness [15–17]. Phylogenetic diversity has been considered a useful surrogate for a diversity of traits, which provide ongoing material for evolutionary processes [14,18,19]. Phylogenetic diversity metrics have also been used in determining centres of diversity and distinctiveness [20] and in planning for conservation gains [21,22].

In addition, broader diversity measures may provide insight into community assembly processes, contributing to conservation prioritization. Areas of distantly related species, or "phylogenetic evenness", may indicate refugial areas of conservation significance, whilst

**Citation:** Pearl, H.; Ryan, T.; Howard,M.; Shimizu, Y.; Shapcott, A. DNA Barcoding to Enhance Conservation of Sunshine Coast Heathlands. *Diversity* **2022**, *14*, 436. https:// doi.org/10.3390/d14060436

Academic Editors: W. John Kress, Morgan Gostel and Michael Wink

Received: 28 March 2022 Accepted: 23 May 2022 Published: 29 May 2022

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areas of "phylogenetic clustering" could represent locations where species had been subject to environmental filtering, such as recently expanded communities [23,24]. Deep-past and biogeographical origins may impact on the observed phylogenetic structuring of communities [21,25–27].

However, phylogenetic metrics used in understanding community assembly may be used differently in conservation [14]. For example, low diversity "phylogenetically clustered" areas may sugges<sup>t</sup> compelling and distinctive community assembly patterns, but these areas may then be viewed as unimportant for conservation. However, when considered together, patterns of diversity, including species richness and composition, along with phylogenetic diversity and structuring, could all contribute to understanding local ecological processes and history [28]. Can diversity metrics be used in concert to contribute to an understanding of the floristic history of a region and so inform the prioritization of conservation areas in a region? This study aimed to explore this question in a system under pressure in the south-east corner of Queensland, Australia.

For millennia, the heathlands of the Sunshine Coast have been a source of sustenance for indigenous people [29], as reflected in the many place names and indigenous words, such as "wallum" to describe *Banksia aemula* and associated plant communities [30,31]. The area is under development pressure as one of the fastest growing regions in Australia [32–34]. The heathlands are threatened by land clearing, forestry, urbanisation, inappropriate fire regimes, and climate change [35,36]. In the 1960s it was recognized that the heathland grew on low-nutrient soils, with terminology such as "depauperate" heath and sedge communities used to describe the "poverty" of these lowlands [36]. Indeed, it is theorised the Australian heath evolved in infertile, seasonally waterlogged soils on the fringes of rainforest, with sclerophylly being an adaptation to low nutrients [37–40]. Thus, it is predicted that the heathlands should have a lower phylogenetic diversity than the surrounding rainforest, but is this so? Previous phylogenetic work in the surrounding rainforests offers an opportunity to explore this [15–17,41].

Almost all heathland species in Australia are endemic to this continent and many are localised [35], including in the heaths of the south-east corner of Queensland [36,37,42]. A major centre of endemism and floristic distinctiveness, corresponding to the "wallum" landscapes, has been identified along this coastal fringe north of Brisbane [43]. This is echoed in the occurrences of other significant biota in these heaths, including the eastern ground parrot and the acid frogs [44,45]. These coastal heaths lie on a complex landscape of coastal sand plains and dunes (Holocene and Pleistocene), alluvium, decomposed sandstones, and volcanic basalts on hills and ranges [46,47]. Are the montane areas with heterogenous environments "phylogenetically even", reflecting local genetic studies [48] and the broader ecological findings of increased diversity in topographical heterogenous areas [49–51]?

There remain areas of heathlands that still reflect the pre-European, or "pre-clearing" conditions. In Queensland, vegetation communities are classified into "regional ecosystems" (RE). This framework, instigated in 1999, is used by private and governmen<sup>t</sup> land managers for biodiversity and conservation assessment and managemen<sup>t</sup> [52]. On the Sunshine Coast, the variation in the heath communities is reflected in nine heathland regional ecosystems. All have a predominant sclerophyllous shrub layer with a restiad or sedge ground-layer, growing either on wet and waterlogged substrates or on dry sands or rocky peaks [53]. The regional ecosystem classification, along with the beginnings of a barcode library for the local heath flora, provides an opportunity to assess the patterns of diversity and distinctiveness and the conservation significance of the heathland types.
