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Climate change has driven contemporary decline and loss of kelp forests globally with an accompanying loss of their ecological and economic values. Kelp populations at equatorward-range edges are particularly vulnerable to climate change as these locations are undergoing warming at or beyond thermal tolerance thresholds. Concerningly, these range-edge populations may contain unique adaptive or evolutionary genetic diversity that is vulnerable to warming. We explore haplotype diversity by generating a Templeton–Crandall–Sing (TCS) network analysis of 119 Cytochrome C Oxidase (COI) sequences among four major population groupings for extant and putatively extinct populations only known from herbarium specimens of the dominant Laminarian kelp Ecklonia radiata in the south-western Pacific, a region warming at 2–4 times the global average. Six haplotypes occurred across the region with one being widespread across most populations. Three unique haplotypes were found in a deep-water range-edge population off Moreton Island, Queensland, which likely represents both a contemporary and historic refuge during periods of climatic change. Hindcasting E. radiata cover estimates using extant data, we reveal that this region likely supported the highest kelp cover in eastern Australia during the last glacial maximum. The equatorward range edge, deep-water kelp populations off Moreton Island represent a genetically diverse evolutionary refuge that is currently threatened by warming and requires prompt ex-situ conservation measures. [ABSTRACT FROM AUTHOR]

Globally, anthropogenic climate change has caused declines of seagrass ecosystems necessitating proactive restoration approaches that would ideally anticipate future climate scenarios, such as marine warming. In eastern Australia, estuaries with meadows of the endangered seagrass Posidonia australi s have warmed and acidified over the past decade, and seagrass communities have declined in some estuaries. Securing these valuable habitats will require proactive conservation and restoration efforts that could be augmented with restoration focussed on boosting resilience to future climate. Understanding patterns of selection and where seagrass meadows are adapted to particular environmental conditions is key for identifying optimal donor material for restoration. We used single nucleotide polymorphisms and genotype by environment analyses to identify candidate loci under putative selection to environmental stressors and assess genomic variation and allelic turnover along stressor gradients. The most important physicochemical variables driving selection were associated with temperature, water turbidity, and pH. We developed a preliminary 'donor registry' of pre-adapted P. australis genotypes by mapping the distribution of alleles to visualise allelic composition of each sampled seagrass meadow. The registry could be used as a first step to select source material for future-proofing restoration projects. A next step is to establish manipulative experiments that will be required to test whether pre-adapted genotypes confer increased resistance to multiple environmental stressors., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Author(s). Ecology and Evolution published by John Wiley & Sons Ltd.)

Matt J. Nimbs, Richard C. Willan, and Stephen D. A. Smith (2017) Recent studies have highlighted the great diversity of sea hares (Aplysiidae) in central New South Wales, but their distribution elsewhere in Australian waters has not previously been analysed. Despite the fact that they are often very abundant and occur in readily accessible coastal habitats, much of the published literature on Australian sea hares concentrates on their taxonomy. As a result, there is a paucity of information about their biology and ecology. This study, therefore, had the objective of compiling the available information on distribution and diet of aplysiids in continental Australia and its offshore island territories to identify important knowledge gaps and provide focus for future research efforts. Aplysiid diversity is highest in the subtropics on both sides of the Australian continent. Whilst animals in the genus Aplysia have the broadest diets, drawing from the three major algal groups, other aplysiids can be highly specialised, with a diet that is restricted to only one or a few species. Although the diets of some widespread, frequently-observed taxa have been investigated, those for lesser-known, endemic taxa remain unclear and require specific investigation.