ORCID Profile
0000-0002-0124-1645
Current Organisation
NSW Department of Primary Industries
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Springer Science and Business Media LLC
Date: 20-08-2016
Publisher: Springer US
Date: 08-11-2021
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 2016
Publisher: Wiley
Date: 25-02-2022
Abstract: Microbial organisms, environmental conditions and their interactions govern many ecosystem processes. Recent studies have highlighted the importance of priority effects, that is, the identity of potential decomposers present early in community assembly, in determining resulting decay rates especially for wood. In erse forests, available woody substrates differ chemically and structurally with implications for their role as both habitats and resources for microbes. Both wood traits and microbial communities at the start of the decay process affect subsequent decay rates, but the relative magnitude of effects is not known. In this work, we sought to ask a simple question: what are the relative effects of microbial communities and wood traits? We characterized fungal and oomycete endophytes with licon sequencing from stems of 22 woody species growing in woodlands near Richmond, NSW, Australia, and measured 11 traits to capture variation in the physical and chemical wood substrates. To evaluate the consequence of endophyte ersity and wood traits on the trajectory of decay, stem s les were sequentially harvested over 5 years to quantify the decay rate, its consistency and how it varies through time. We did not find evidence to support particular initial endophyte compositions leading to faster decay. Instead, initial wood attributes were much more powerful in explaining decay trajectories with smaller, less dense stems with high water, low N and low lignin concentrations decomposing consistently faster. These data show that initial wood traits have long‐lasting consequences on decay unlike natural variation in endophyte communities, supporting the idea that community member functions are highly redundant. Wood substrate‐driven environmental filtering, rather than endophyte‐driven priority effects, had a stronger effect on decay when real‐world levels of ersity in wood traits were considered. Read the free Plain Language Summary for this article on the Journal blog.
Publisher: Wiley
Date: 24-07-2019
DOI: 10.1002/ECY.2790
Abstract: Environmental forces and biotic interactions, both positive and negative, structure ecological communities, but their relative roles remain obscure despite strong theory. For instance, ecologically similar species, based on the principle of limiting similarity, are expected to be most competitive and show negative interactions. Specious communities that assemble along broad environmental gradients afford the most power to test theory, but the communities often are difficult to quantify. Microbes, specifically fungal endophytes of wood, are especially suited for testing community assembly theory because they are relatively easy to s le across a comprehensive range of environmental space with clear axes of variation. Moreover, endophytes mediate key forest carbon cycle processes, and although saprophytic fungi from dead wood typically compete, endophytic fungi in living wood may enhance success through cooperative symbioses. To classify interactions within endophyte communities, we analyzed fungal DNA barcode variation across 22 woody plant species growing in woodlands near Richmond, New South Wales, Australia. We estimated the response of endophytes to the measured wood environment (i.e., 11 anatomical and chemical wood traits) and each other using latent-variable models and identified recurrent communities across wood environments using model-based classification. We used this information to evaluate whether (1) co-occurrence patterns are consistent with strong competitive exclusion, and (2) a priori classifications by trophic mode and phylum distinguish taxa that are more likely to have positive vs. negative associations under the principle of limiting similarity. Fungal endophytes were erse (mean = 140 taxa/s le), with differences in community composition structured by wood traits. Variation in wood water content and carbon concentration were associated with especially large community shifts. Surprisingly, after accounting for wood traits, fungal species were still more than three times more likely to have positive than negative co-occurrence patterns. That is, patterns consistent with strong competitive exclusion were rare, and positive interactions among fungal endophytes were more common than expected. Confirming the frequency of positive vs. negative interactions among fungal taxa requires experimental tests, and our findings establish clear paths for further study. Evidence to date intriguingly suggests that, across a wide range of wood traits, cooperation may outweigh combat for these fungi.
Publisher: CSIRO Publishing
Date: 21-08-2021
DOI: 10.1071/CP20234
Abstract: Perennial legumes have potential to increase pasture productivity in the high rainfall zone (600–850 mm) of south-eastern Australia through their ability to use summer rainfall and fix nitrogen (N2). Various perennial legumes are being evaluated for this environment however, little information exists on legume–rhizobia cross-host compatibility and its consequences for biological N2 fixation. This is especially important when legumes are sown into fields with a background of competitive rhizobia such as WSM1325 or sown as a pasture mix with different host–symbiont pairs. We studied the effectiveness and cross-host compatibility of five commercial rhizobial strains for a range of pasture legumes (nine species, 18 cultivars) under controlled environment conditions, and further evaluated nodule occupancy and competitiveness of a newly established pasture (13 species, 20 cultivars) in the field, by determining nodulation and production (biomass and N2 fixation). Three of the commercial inoculant strains formed root nodules with multiple legume species commonly however, less N2 was fixed in cases where the inoculant was not the recommended strain for the legume species. Within a legume species, cultivars could differ in their ability to form effective root nodules with multiple rhizobial strains. White clover cvv. Trophy, Haifa and Storm, strawberry clover cv. Palestine, and Talish clover cv. Permatas formed effective nodules with both TA1 and WSM1325 rhizobial strains. White clover cultivars that could not form an effective symbiosis with the common background strain WSM1325 fixed less N2. The white clover × Caucasian clover hybrid formed effective symbiosis with strain TA1 but not with other commercial strains. Some species such as birdsfoot trefoil, Talish clover, sulfur clover and tetraploid Caucasian clover formed ineffective symbiosis in the field. Until resolved, this will likely inhibit their further development as pasture plants for similar permanent pasture environments.
Publisher: CSIRO Publishing
Date: 20-10-2021
DOI: 10.1071/SR20264
Abstract: Context Success of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) is dependent on a range of soil factors including pH and soil organic carbon (OC) content. Aims This study identified the effect of soil properties and moisture content at the time of DMPP application on the efficiency of DMPP and soil mineral N concentrations. Methods Soil was collected from paired paddocks with contrasting management, cropping or pasture across three sites. Soil s les were pre-incubated for 7 days with moist (−85 kPa) or air dried soil to simulate sowing into soil with moisture equivalents of post seasonal break or dry sowing. Urea ammonium nitrate (UAN) was applied with and without DMPP to all soils. Key results DMPP inhibited nitrification in all soils, although decreased inhibitory effectiveness was observed in acidic soils compared to neutral soils. Inhibition efficacy on acidic soils was improved when DMPP was applied to dry rather than wet soils. Neutral soils did not observe the same soil moisture effect having similar inhibition efficiency of DMPP observed between dry and wet soil application. Nitrogen fertilisers applied to dry soils nitrified at a greater rate than when applied to wet soils. DMPP decreased the ammonia oxidising bacteria (AOB) population while the ammonia oxidising archaea (AOA) amoA gene copy numbers were unaffected. Conclusions This study shows that the lower soil pH and high OC contents can reduce the efficacy of DMPP. Implications When using DMPP in Australian broad acre agriculture, knowledge of soil properties including soil pH will determine if application of DMPP is suitable for use before or after a seasonal break rainfall event.
Publisher: Elsevier BV
Date: 2008
Publisher: Wiley
Date: 12-2016
DOI: 10.1002/ECY.1594
Abstract: Plant-soil feedback, the reciprocal relationship between a plant and its associated microbial communities, has been proposed to be an important driver of plant populations and community dynamics. While rarely considered, understanding how plant-soil feedback contributes to plant rarity may have implications for conservation and management of rare species. Wollemi pine (Wollemia nobilis) is a critically endangered species, of which fewer than 100 trees are known to exist in the wild. Seedling survival within the first year after germination and subsequent recruitment of Wollemi pine is limited in the wild. We used a plant-soil feedback approach to investigate the functional effect of species-specific differences previously observed in the microbial communities underneath adult Wollemi pine and a neighboring species, coachwood (Ceratopetalum apetalum), and also whether additional variation in microbial communities in the wild could impact seedling growth. There was no evidence for seedling growth being affected by tree species associated with soil inocula, suggesting that plant-soil feedbacks are not limiting recruitment in the natural population. However, there was evidence of fungal, but not bacterial, community variation impacting seedling growth independently of plant-soil feedbacks. Chemical (pH) and physical (porosity) soil characteristics were identified as potential drivers of the functional outcomes of these fungal communities. The empirical approach described here may provide opportunities to identify the importance of soil microbes to conservation efforts targeting other rare plant species and is also relevant to understanding the importance of soil microbes and plant-soil feedbacks for plant community dynamics more broadly.
Publisher: Springer Science and Business Media LLC
Date: 21-05-2018
No related grants have been discovered for Jessica Rigg.