ORCID Profile
0000-0003-4519-4008
Current Organisation
NSW Department of Planning, Industry and Environment
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Publisher: The Royal Society
Date: 28-06-2023
Publisher: Wiley
Date: 12-2017
Publisher: Wiley
Date: 30-07-2023
DOI: 10.1111/REC.13987
Abstract: Analyses of erse aboveground and belowground indicators should underpin assessments of ecosystem recovery, yet monitoring many indicators is costly and their integration is challenging. Our objective was to combine indicators through a Bayesian hierarchical model to provide a comprehensive assessment of ecosystem status and identify a cost‐effective subset of indicators to provide an accurate estimate of ecosystem recovery. We assessed 59 aboveground–belowground indicators, classified into nine components of composition, structure, and function, to estimate the ecosystem status of restored rock spoils and reference forests in south‐eastern Australia. Overall ecosystem status, which integrates across ecosystem components and supporting indicators, was lower within restored forests but positively correlated with forest age. Reference forests had greater aboveground and belowground biotic structure, organic matter supply, and soil carbon stability, and trends were consistent among all of their supporting indicators. A subset of organic matter quality and nutrient cycling indicators were greater within restored forests, suggesting high ecosystem process rates, but that soil carbon may be more vulnerable to loss. Aboveground biotic structure was correlated with organic matter supply and quality, stability of soil carbon, the cycling of nutrients, and belowground biotic structure, providing evidence of aboveground–belowground coupling. A combination of four indicators representing belowground biotic structure, soil carbon stability, organic matter supply, and aboveground composition, provided a good estimate of ecosystem status at a third of the cost. Although ecosystem status can be monitored with a small set of indicators, a ersity of aboveground–belowground indicators provide a robust and comprehensive assessment of recovery.
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/AM11031
Publisher: Wiley
Date: 13-03-2020
DOI: 10.1111/AVSC.12486
Publisher: Wiley
Date: 12-09-2018
Publisher: Proceedings of the National Academy of Sciences
Date: 08-09-2020
Publisher: Cold Spring Harbor Laboratory
Date: 27-06-2022
Publisher: Elsevier BV
Date: 05-2019
Publisher: Elsevier BV
Date: 08-2019
Publisher: American Association for the Advancement of Science (AAAS)
Date: 13-01-2012
Abstract: The relationship between species richness and the functional properties of their ecosystems has often been studied at small scales in experimental plots. Maestre et al. (p. 214 see the Perspective by Midgley ) performed field measurements at 224 dryland sites from six continents and assessed 14 ecosystem functions related to carbon, nitrogen, and phosphorus cycling. Positive relationships were observed between perennial plant species richness and ecosystem functionality. The relative importance of bio ersity was found to be as large as, or larger than, many key abiotic variables. Thus, preservation of plant bio ersity is important to buffer negative effects of climate change and desertification in drylands, which collectively cover 41% of Earth's land surface and support over 38% of the human population.
Publisher: Wiley
Date: 21-07-2014
DOI: 10.1111/JBI.12377
Publisher: Wiley
Date: 30-01-2019
Publisher: Elsevier BV
Date: 06-2013
Publisher: Wiley
Date: 17-04-2021
Abstract: Plant‐associated microbes play essential roles in nutrient uptake and plant productivity, but their role in driving plant germination, a critical stage in the plant life cycle, is still poorly understood. We used data from a large‐scale, field‐based soil seed bank study to examine the relationship among plants germinating from the seed bank and soil microbial community composition. We combined this with an experiment using 34 laboratory‐based microcosms whereby sterile soil was inoculated with microbes from different field sites to examine how microbes affect the germination of nine plant species. The community composition of plants in the soil seed bank was highly and significantly associated with bacterial and fungal community composition, with stronger correlations for soil beneath plant canopies. Microbes predicted a unique portion of the variation in the community composition of germinants after accounting for differences in environmental variables. The strongest correlations among microbes and plant functional traits included those related to perenniality, growth form, plant size, root type and seed shape. Our microcosm study showed that different plant species had their own associated germination microbiome, and most plant–microbe interactions were positive during germination. Synthesis . Our study provides evidence for intimate relationships between plant and soil bio ersity during germination. Our work fills an important knowledge gap for plant–microbe interactions and reveals valuable insights into the shared natural history of plants and microbes in terrestrial ecosystems.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Wiley
Date: 09-10-2015
DOI: 10.1111/NPH.13688
Abstract: The increase in aridity predicted with climate change will have a negative impact on the multiple functions and services (multifunctionality) provided by dryland ecosystems worldwide. In these ecosystems, soil communities dominated by mosses, lichens and cyanobacteria (biocrusts) play a key role in supporting multifunctionality. However, whether biocrusts can buffer the negative impacts of aridity on important biogeochemical processes controlling carbon (C), nitrogen (N), and phosphorus (P) pools and fluxes remains largely unknown. Here, we conducted an empirical study, using s les from three continents (North America, Europe and Australia), to evaluate how the increase in aridity predicted by climate change will alter the capacity of biocrust‐forming mosses to modulate multiple ecosystem processes related to C, N and P cycles. Compared with soil surfaces lacking biocrusts, biocrust‐forming mosses enhanced multiple functions related to C, N and P cycling and storage in semiarid and arid, but not in humid and dry‐subhumid, environments. Most importantly, we found that the relative positive effects of biocrust‐forming mosses on multifunctionality compared with bare soil increased with increasing aridity. These results were mediated by plant cover and the positive effects exerted by biocrust‐forming mosses on the abundance of soil bacteria and fungi. Our findings provide strong evidence that the maintenance of biocrusts is crucial to buffer negative effects of climate change on multifunctionality in global drylands.
Publisher: Wiley
Date: 03-2022
DOI: 10.1111/JVS.13115
Publisher: Wiley
Date: 07-2018
DOI: 10.1111/JVS.12665
Publisher: Elsevier BV
Date: 07-2020
Publisher: Royal Zoological Society of New South Wales
Date: 2012
DOI: 10.7882/AZ.2012.004
Publisher: Wiley
Date: 29-05-2011
Publisher: Wiley
Date: 10-10-2018
DOI: 10.1111/AVSC.12334
Publisher: Wiley
Date: 07-10-2015
DOI: 10.1111/GEB.12382
Publisher: Wiley
Date: 30-07-2020
DOI: 10.1111/JVS.12916
Publisher: Wiley
Date: 04-06-2013
Publisher: Springer Science and Business Media LLC
Date: 30-09-2020
Publisher: Wiley
Date: 16-05-2022
DOI: 10.1111/AEC.13184
Publisher: Wiley
Date: 30-05-2018
DOI: 10.1111/GCB.14306
Abstract: The role of climatic legacies in regulating community assembly of above- and belowground species in terrestrial ecosystems remains largely unexplored and poorly understood. Here, we report on two separate regional and continental empirical studies, including >500 locations, aiming to identify the relative importance of climatic legacies (climatic anomaly over the last 20,000 years) compared to current climates in predicting the relative abundance of ecological clusters formed by species strongly co-occurring within two independent above- and belowground networks. Climatic legacies explained a significant portion of the variation in the current community assembly of terrestrial ecosystems (up to 15.4%) that could not be accounted for by current climate, soil properties, and management. Changes in the relative abundance of ecological clusters linked to climatic legacies (e.g., past temperature) showed the potential to indirectly alter other clusters, suggesting cascading effects. Our work illustrates the role of climatic legacies in regulating ecosystem community assembly and provides further insights into possible winner and loser community assemblies under global change scenarios.
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/BT19183
Publisher: Wiley
Date: 12-06-2017
DOI: 10.1002/ECY.1879
Abstract: Scientists have largely neglected the effects of grazing on soil microbial communities despite their importance as drivers of ecosystem functions and services. We hypothesized that changes in soil properties resulting from grazing regulate the ersity of soil microbes by releasing/suppressing subordinate microbial taxa via competition. To test this, we examined how intensity of vertebrate herbivores influences the ersity and composition of soil bacteria and fungi at 216 soil s les from 54 sites across four microsites. Increasing grazing intensity reduced soil carbon, suppressing the dominant bacterial phylum Actinobacteria (indirectly promoting bacterial ersity) and increasing the dominant fungal phylum Ascomycetes (indirectly reducing fungal ersity). Our data provide novel evidence that grazing modulates the ersity and composition of soil microbes via increases or reductions in competition by dominant taxa. Our results suggest that grazing can potentially alter soil function by altering microbial community composition, providing a clear link between grazing management, carbon availability and ecosystem functions.
Publisher: Wiley
Date: 09-02-2018
Publisher: Wiley
Date: 25-01-2016
DOI: 10.1002/ECO.1831
Publisher: Wiley
Date: 15-09-2023
DOI: 10.1111/COBI.14151
Abstract: Identifying threatened ecosystem types is fundamental to conservation and management decision‐making. When identification relies upon the judgment of suitably trained experts, decisions are vulnerable to inconsistent outcomes and can lack transparency. We elicited judgements of the occurrence of a widespread, critically endangered Australian ecosystem from a erse pool of 83 experts. We asked: (1) How many experts are required to reliably conclude that the ecosystem is present? (2) How many experts are required to build a reliable model for predicting ecosystem presence? (3) Given expert selection can narrow the range opinions, if enough experts are selected, do selection strategies affect model predictions? (4) Does a erse selection of experts provide better model predictions? We used power and s le size calculations with a finite population of 200 experts to calculate the number of experts required to reliably assess ecosystem presence in a theoretical scenario. We then used boosted regression trees to model expert elicitation of 122 plots based on real‐world data. For a reliable consensus (90% probability of correctly identifying presence and absence), in a relatively certain scenario (85% probability of occurrence) we found at least 17 experts were required. More experts are required when occurrence was less certain fewer if permissible error rates are relaxed. In comparison, only ∼20 experts were required for a reliable model that could predict for a range of scenarios. Expert selection strategies changed modelled outcomes, often overpredicting presence and underestimate uncertainty. However, smaller but erse pools of experts produced similar outcomes to a model built from all contributing experts. Combining elicited judgements from a erse pool of experts in a model‐based decision support tool provides an efficient aggregation of a broad range of expertise. Such models can improve the transparency and consistency of conservation and management decision‐making especially when ecosystems are defined by complex criteria. This article is protected by copyright. All rights reserved
Publisher: Cold Spring Harbor Laboratory
Date: 10-2021
Publisher: American Association for the Advancement of Science (AAAS)
Date: 25-11-2022
Abstract: Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and bio ersity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that interactions between grazing pressure, climate, soil, and bio ersity are critical to explain the delivery of fundamental ecosystem services across drylands worldwide. Increasing grazing pressure reduced ecosystem service delivery in warmer and species-poor drylands, whereas positive effects of grazing were observed in colder and species-rich areas. Considering interactions between grazing and local abiotic and biotic factors is key for understanding the fate of dryland ecosystems under climate change and increasing human pressure.
Publisher: Springer Science and Business Media LLC
Date: 28-02-2023
Publisher: Springer Science and Business Media LLC
Date: 10-2013
DOI: 10.1038/NATURE12670
Abstract: The biogeochemical cycles of carbon (C), nitrogen (N) and phosphorus (P) are interlinked by primary production, respiration and decomposition in terrestrial ecosystems. It has been suggested that the C, N and P cycles could become uncoupled under rapid climate change because of the different degrees of control exerted on the supply of these elements by biological and geochemical processes. Climatic controls on biogeochemical cycles are particularly relevant in arid, semi-arid and dry sub-humid ecosystems (drylands) because their biological activity is mainly driven by water availability. The increase in aridity predicted for the twenty-first century in many drylands worldwide may therefore threaten the balance between these cycles, differentially affecting the availability of essential nutrients. Here we evaluate how aridity affects the balance between C, N and P in soils collected from 224 dryland sites from all continents except Antarctica. We find a negative effect of aridity on the concentration of soil organic C and total N, but a positive effect on the concentration of inorganic P. Aridity is negatively related to plant cover, which may favour the dominance of physical processes such as rock weathering, a major source of P to ecosystems, over biological processes that provide more C and N, such as litter decomposition. Our findings suggest that any predicted increase in aridity with climate change will probably reduce the concentrations of N and C in global drylands, but increase that of P. These changes would uncouple the C, N and P cycles in drylands and could negatively affect the provision of key services provided by these ecosystems.
Publisher: Elsevier BV
Date: 05-2019
Location: Australia
No related grants have been discovered for James Val.