<p>The depletion and degradation of native plant communities is a major threat to the long-term health and functionality of many ecosystems worldwide. Some of the current challenges in mine rehabilitation programs are poor recruitment and establishment of native plants. Indigenous soil bacteria, including cyanobacteria from soil biocrusts, have shown promise as bio-fertilizers as they may promote germination and enhance seedling growth of native plants in reconstructed soil profiles. In this research, we assessed the potential of bioinoculants composed by locally sourced soil bacteria from the rhizosphere and cyanobacteria from biocrusts, to promote germination and growth of native arid plants from Western Australia and New South Wales (Australia). Individual cyanobacteria species (e.g. Leptolyngbya sp, Nostoc sp. and Microcoleus sp), a cyanobacteria mix of these three species, and enrichments of soil bacteria from the rhizosphere were considered as inoculum for seed bio-priming. Overall, our results showed that lower concentrations of cyanobacteria inoculants (1 g l<sup>-1</sup>) are more effective for promoting seedling growth than highly concentrated inoculum (5 g l<sup>-1</sup>). The effects of the cyanobacterial/bacterial inoculants were specific to each plant species. However, biopriming seeds with soil bacteria and the cyanobacteria mix resulted in three times larger roots in hummock grasses (e.g. Triodia epactia) compared to the control treatment. We also identified the bio-active components or metabolites produced by targeted cyanobacteria species through GC/MS analyses. Our results showed that some of the cyanobacterial inoculants produced substances chemically like plant hormones such as auxins, i.e. indole-3-acetic acid. The positive effects of the native soil bacteria and cyanobacteria inoculants on native plants could be related to their ability of promoting nutrient bioavailability, improving stress resistance, protection against other microbes, and production of substances that may act as hormones. The findings of this research can allow selecting the most effective bio-active inoculants for application in seed-based land rehabilitation programs.</p>

IntroductionBiocrust cyanobacteria have a large potential as biofertilizers for restoring degraded ecosystems because of their ability to improve soil nutrition and stabilisation, and to produce metabolites such as phytohormones to enhance plant growth. However, important aspects regarding the effects of cyanobacteria on native plants, such as metabolite production or concentration of inoculants, remain unknown. Here, we investigated the effects of different concentrations of cyanobacteria, on the germination and seedling growth of keystone plant species used in dryland restoration. We hypothesised that the studied inoculant would improve germination and seedling growth rates, with specific effects associated with the inoculant's concentration and metabolomic profiles.MethodsWe bioprimed seeds of four native plant species, using a cyanobacterial inoculant with different proportions of Nostoc and Leptolyngbya at two different concentrations. We recorded germination, measured seedling growth, and determined the corrected vigour for each treatment and species. Metabolites produced by the cyanobacterial inoculant were assessed to identify plant growth hormones potentially driving any effects.ResultsThere was a clear positive effect on the total germination of Triodia epactia and Triodia wiseana, but negative impacts for Senna notabilis and Grevillea wickhamii. There were also positive effects on root growth, but only for T. epactia, with negative or neutral impacts on the root and shoot growth of other species tested. We detected phytohormones, salicylic acid and indole‐3‐acetic acid, that were produced by our cyanobacteria inoculant, which are strongly linked to positive effects in early plant growth stages, but also known to inhibit growth when in higher concentrations.ConclusionThe positive effects of the biopriming protocol used are not uniform and highlight the need to improve our understanding of the effects provided both from different consortia and the concentrations applied when inoculating. There is a very high value in improving restoration outcomes for native vegetation communities in arid and semi‐arid regions.

Platypuses (Ornithorhynchus anatinus) inhabit the permanent rivers and creeks of eastern Australia, from north Queensland to Tasmania, but are experiencing multiple and synergistic anthropogenic threats. Baseline information of health is vital for effective monitoring of populations but is currently sparse for mainland platypuses. Focusing on seven hematology and serum chemistry metrics as indicators of health and nutrition (packed cell volume (PCV), total protein (TP), albumin, globulin, urea, creatinine, and triglycerides), we investigated their variation across the species’ range and across seasons. We analyzed 249 unique samples collected from platypuses in three river catchments in New South Wales and Victoria. Health metrics significantly varied across the populations’ range, with platypuses from the most northerly catchment, having lower PCV, and concentrations of albumin and triglycerides and higher levels of globulin, potentially reflecting geographic variation or thermal stress. The Snowy River showed significant seasonal patterns which varied between the sexes and coincided with differential reproductive stressors. Male creatinine and triglyceride levels were significantly lower than females, suggesting that reproduction is energetically more taxing on males. Age specific differences were also found, with juvenile PCV and TP levels significantly lower than adults. Additionally, the commonly used body condition index (tail volume index) was only negatively correlated with urea, and triglyceride levels. A meta-analysis of available literature revealed a significant latitudinal relationship with PCV, TP, albumin, and triglycerides but this was confounded by variation in sampling times and restraint methods. We expand understanding of mainland platypuses, providing reference intervals for PCV and six blood chemistry, while highlighting the importance of considering seasonal variation, to guide future assessments of individual and population condition.

<p>Arid and semi-arid (from hereafter dryland) ecosystems cover 70% of Australia, with climate change set to increase this area through desertification. Increased temperatures and reduced water availability are compounded through agricultural overgrazing. This degradation and habitat loss has led to biodiversity loss which disrupts the biogeochemical cycles that maintain these environments, creating a negative feedback loop, and making restoration efforts largely unsuccessful. With soil microbes being important drivers in dryland systems, understanding how different stressors impact the soil biome is needed to improve conservation and restoration efforts and promote resilience and resistance to climate change. Particularly lacking is understanding of these interactions over time.</p><p>Fowlers Gap Research Station is the only research station in the arid zone of Australia and was a working sheep station until 2019. Due to agricultural overgrazing the site is largely degraded however exclusion zones have been set up on the property ranging in time from 3 years to 40 years. These exclusion zones provide a powerful comparison for the impact of soil degradation on drylands. To investigate the impact of overgrazing on the soil biodiversity and ecosystem functions, we selected three of the exclusion zones paired with three degraded sites directly outside of the exclusion zone to assess their microbial composition and functional diversity, along with soil physicochemical properties. We aim to build 16S rRNA gene libraries and co-relate them with the soil chemical variables, to assess the impact of overgrazing on these microbial communities and the ecosystem functions they provide. This knowledge can be used to improve monitoring of conservation and restoration initiatives by providing environmental indicators for soil health over time.</p>