Fine roots acquire essential soil resources and mediate biogeochemical cycling in terrestrial ecosystems. Estimates of carbon and nutrient allocation to build and maintain these structures remain ...uncertain because of the challenges of consistently measuring and interpreting fine-root systems. Traditionally, fine roots have been defined as all roots ≤ 2 mm in diameter, yet it is now recognized that this approach fails to capture the diversity of form and function observed among fine-root orders. Here, we demonstrate how order-based and functional classification frameworks improve our understanding of dynamic root processes in ecosystems dominated by perennial plants. In these frameworks, fine roots are either separated into individual root orders or functionally defined into a shorter-lived absorptive pool and a longer-lived transport fine-root pool. Using these frameworks, we estimate that fine-root production and turnover represent 22% of terrestrial net primary production globally – a c. 30% reduction from previous estimates assuming a single fine-root pool. Future work developing tools to rapidly differentiate functional fine-root classes, explicit incorporation of mycorrhizal fungi into fine-root studies, and wider adoption of a two-pool approach to model fine roots provide opportunities to better understand below-ground processes in the terrestrial biosphere.
Ecology Letters (2011) 14: 349–357
The earth’s future climate state is highly dependent upon changes in terrestrial C storage in response to rising concentrations of atmospheric CO2. Here we show ...that consistently enhanced rates of net primary production (NPP) are sustained by a C‐cascade through the root‐microbe‐soil system; increases in the flux of C belowground under elevated CO2 stimulated microbial activity, accelerated the rate of soil organic matter decomposition and stimulated tree uptake of N bound to this SOM. This process set into motion a positive feedback maintaining greater C gain under elevated CO2 as a result of increases in canopy N content and higher photosynthetic N‐use efficiency. The ecosystem‐level consequence of the enhanced requirement for N and the exchange of plant C for N belowground is the dominance of C storage in tree biomass but the preclusion of a large C sink in the soil.
Abstract We present the outcomes of two conservation initiatives, namely ‘The Australian Crayfish’ and ‘Saving the Spinys’ projects, which have substantially contributed to enhancing our ...understanding of E. spinichelatus concerning its distribution, habitat, biology, and conservation status. We extend the range of E. spinichelatus to encompass the headwater reaches of the Namoi River within the Murray-Darling Basin. The use of molecular taxonomy analyses identified divergent lineages that acted to remove the southeastern tributaries of the Hastings River and the most western tributary of the Manning River from the range of E. spinichelatus. The species has suffered significant population declines in recent years, with it appearing to be highly susceptible to anthropogenic changes, drought and/or high-severity bushfires. Results advocate for the classification of E. spinichelatus as an endangered species, recognizing its distinctive ecological niche and its status as a climate refugee, aiming to protect this rare species from anthropogenic and climate-related challenges. We also present a taxonomic key differentiating E. spinichelatus from other members of Parastacidae in the region.
Abstract Euastacus gamilaroi Morgan 1997, the Gamilaroi crayfish, was initially described based on specimens collected in 1954 from Hanging Rock, New South Wales, but since then scant subsequent ...records hinder conservation of this endangered species. Extensive sampling during 2006–2023 delineated the distribution, habitat preferences, biological traits, and conservation status of the species. Together with concurrent molecular taxonomic analyses were extend the species range from headwater regions of highland streams above 960 m altitude of Burrows Creek to include highland streams of Duncan and Dungowan creeks (Peel-Namoi River/western drainage) and Tomalla, Back, and Ben Halls creeks (Barnard-Manning River/eastern drainage). We provide information on the distribution, biology, and ecological associations of the species. Results advocate for the classification of E. gamilaroi as an endangered species, recognizing its distinctive ecological niche and its status as a climate refugee, aiming to protect this rare species from climate-related challenges. We also present a taxonomic key differentiating E. gamilaroi from other species of Parastacidae in the region.
Efforts to characterize carbon (C) cycling among atmosphere, forest canopy, and soil C pools are hindered by poorly quantified fine root dynamics. We characterized the influence of ...free-air-CO₂-enrichment (ambient +200 ppm) on fine roots for a period of 6 years (Autumn 1998 through Autumn 2004) in an 18-year-old loblolly pine (Pinus taeda) plantation near Durham, NC, USA using minirhizotrons. Root production and mortality were synchronous processes that peaked most years during spring and early summer. Seasonality of fine root production and mortality was not influenced by atmospheric CO₂ availability. Averaged over all 6 years of the study, CO₂ enrichment increased average fine root standing crop (+23%), annual root length production (+25%), and annual root length mortality (+36%). Larger increase in mortality compared with production with CO₂ enrichment is explained by shorter average fine root lifespans in elevated plots (500 days) compared with controls (574 days). The effects of CO₂-enrichment on fine root proliferation tended to shift from shallow (0-15 cm) to deeper soil depths (15-30) with increasing duration of the study. Diameters of fine roots were initially increased by CO₂-enrichment but this effect diminished over time. Averaged over 6 years, annual fine root NPP was estimated to be 163 g dw m⁻² yr⁻¹ in CO₂-enriched plots and 130 g dw m⁻² yr⁻¹ in control plots (P= 0.13) corresponding to an average annual additional input of fine root biomass to soil of 33 g m⁻² yr⁻¹ in CO₂-enriched plots. A lack of consistent CO₂x year effects suggest that the positive effects of CO₂ enrichment on fine root growth persisted 6 years following minirhizotron tube installation (8 years following initiation of the CO₂ fumigation). Although CO₂-enrichment contributed to extra flow of C into soil in this experiment, the magnitude of the effect was small suggesting only modest potential for fine root processes to directly contribute to soil C storage in south-eastern pine forests.
Ecological theory is built on trade-offs, where trait differences among species evolved as adaptations to different environments. Trade-offs are often assumed to be bidirectional, where opposite ends ...of a gradient in trait values confer advantages in different environments. However, unidirectional benefits could be widespread if extreme trait values confer advantages at one end of an environmental gradient, whereas a wide range of trait values are equally beneficial at the other end. Here, we show that root traits explain species occurrences along broad gradients of temperature and water availability, but model predictions only resembled trade-offs in two out of 24 models. Forest species with low specific root length and high root tissue density (RTD) were more likely to occur in warm climates but species with high specific root length and low RTD were more likely to occur in cold climates. Unidirectional benefits were more prevalent than trade-offs: for example, species with large-diameter roots and high RTD were more commonly associated with dry climates, but species with the opposite trait values were not associated with wet climates. Directional selection for traits consistently occurred in cold or dry climates, whereas a diversity of root trait values were equally viable in warm or wet climates. Explicit integration of unidirectional benefits into ecological theory is needed to advance our understanding of the consequences of trait variation on species responses to environmental change.
Aim
The incidence of major fires is increasing globally, creating extraordinary challenges for governments, managers and conservation scientists. In 2019–2020, Australia experienced precedent‐setting ...fires that burned over several months, affecting seven states and territories and causing massive biodiversity loss. Whilst the fires were still burning, the Australian Government convened a biodiversity Expert Panel to guide its bushfire response. A pressing need was to target emergency investment and management to reduce the chance of extinctions and maximise the chances of longer‐term recovery. We describe the approach taken to rapidly prioritise fire‐affected animal species. We use the experience to consider the organisational and data requirements for evidence‐based responses to future ecological disasters.
Location
Forested biomes of subtropical and temperate Australia, with lessons for other regions.
Methods
We developed assessment frameworks to screen fire‐affected species based on their pre‐fire conservation status, the proportion of their distribution overlapping with fires, and their behavioural/ecological traits relating to fire vulnerability. Using formal and informal networks of scientists, government and non‐government staff and managers, we collated expert input and data from multiple sources, undertook the analyses, and completed the assessments in 3 weeks for vertebrates and 8 weeks for invertebrates.
Results
The assessments prioritised 92 vertebrate and 213 invertebrate species for urgent management response; another 147 invertebrate species were placed on a watchlist requiring further information.
Conclusions
The priority species lists helped focus government and non‐government investment, management and research effort, and communication to the public. Using multiple expert networks allowed the assessments to be completed rapidly using the best information available. However, the assessments highlighted substantial gaps in data availability and access, deficiencies in statutory threatened species listings, and the need for capacity‐building across the conservation science and management sectors. We outline a flexible template for using evidence effectively in emergency responses for future ecological disasters.
Spontaneous combustion of coal seams in the Witbank and Sasolburg coalfields, South Africa, was studied in order to determine if toxic chemical elements and compounds are being mobilised into the ...environment. Samples of the minerals forming on the surface of coal seams, and gases escaping from vents, were analysed to verify the presence of these elements and compounds.
Gas temperature measurements at coal-fire vents range from 34 °C to 630 °C. The coal-fire gas minerals (CFGM) identified included sulphur compounds and salammoniac. X-ray diffraction (XRD) studies of CFGM by-products confirmed the presence of mascagnite ((NH
4)
2SO
4), illite ((Al,Si)
4O
10(OH)
2,H
2O) letovicite ((NH
4)
3H(SO
4)
2), phlogopite (KMg
3(AlSi
3)O
10(F,OH)
2), titanium dioxide (TiO
2), barite (BaSO
4), iron sulphate (FeSO
4), gypsum (CaSO
4·2H
2O) and silicate. An unknown and unclassified sulphur–nitrogen–chlorine CFGM was also identified. The minerals are interpreted to have formed by condensation or sublimation; several may be alteration products. Other heavy elements found in the CFGM's are mercury, arsenic, lead, zinc, and copper. Arsenic and mercury were the major elements of potential environmental significance found accumulating around coal-fire vents.
Relatively high concentrations of toluene, benzene and xylene were found in the gas collected at both Witbank and Sasolburg coalfields. Benzene, toluene and xylenes are known to possess carcinogenic proprieties. Thirty-two aliphatic compounds were detected, as well as halogenated compounds including bromomethane, iodomethane and trichloromethane in low concentrations, and dichloromethane and chloromethane in high concentrations. The highest concentrations of halogenated compounds were measured for gas samples from the Witbank coalfield. High concentrations of carbon monoxide, carbon dioxide, and methane were also detected.
The nature of the risks to human health and the environment of most of the compounds in gas and CFGM by-products of spontaneous combustion at the Witbank and Sasolburg coalfields are unknown and merit investigation. Fires caused by spontaneously combusted coal are pervasive in the coalfields and the health consequences of exposure to hazardous elements are a serious risk. It would be prudent to undertake an environmental impact assessment of these elements in order to determine the extent of their impact on mine workers and the environment in the Witbank and Sasolburg coalfields.
Individuals with Friedreich ataxia (FRDA) can find it difficult to access specialized clinical care. To facilitate best practice in delivering healthcare for FRDA, clinical management guidelines ...(CMGs) were developed in 2014. However, the lack of high-certainty evidence and the inadequacy of accepted metrics to measure health status continues to present challenges in FRDA and other rare diseases. To overcome these challenges, the Grading of Recommendations Assessment and Evaluation (GRADE) framework for rare diseases developed by the RARE-Bestpractices Working Group was adopted to update the clinical guidelines for FRDA. This approach incorporates additional strategies to the GRADE framework to support the strength of recommendations, such as review of literature in similar conditions, the systematic collection of expert opinion and patient perceptions, and use of natural history data.
A panel representing international clinical experts, stakeholders and consumer groups provided oversight to guideline development within the GRADE framework. Invited expert authors generated the Patient, Intervention, Comparison, Outcome (PICO) questions to guide the literature search (2014 to June 2020). Evidence profiles in tandem with feedback from individuals living with FRDA, natural history registry data and expert clinical observations contributed to the final recommendations. Authors also developed best practice statements for clinical care points that were considered self-evident or were not amenable to the GRADE process.
Seventy clinical experts contributed to fifteen topic-specific chapters with clinical recommendations and/or best practice statements. New topics since 2014 include emergency medicine, digital and assistive technologies and a stand-alone section on mental health. Evidence was evaluated according to GRADE criteria and 130 new recommendations and 95 best practice statements were generated.
Evidence-based CMGs are required to ensure the best clinical care for people with FRDA. Adopting the GRADE rare-disease framework enabled the development of higher quality CMGs for FRDA and allows individual topics to be updated as new evidence emerges. While the primary goal of these guidelines is better outcomes for people living with FRDA, the process of developing the guidelines may also help inform the development of clinical guidelines in other rare diseases.
Euastacus vesper sp. nov., is described from the upper Cudgegong River, Coricudgy State Forest, New South Wales, Australia. The new species occurs in the western drainage of the Great Dividing Range, ...and is most closely related to E. spinifer (Heller, 1865), which occurs on the eastern side of the range. Euastacus vesper differs from E. spinifer by its considerably smaller maximum size (OCL 67.9 mm versus 116.7 mm), greater degree of thoracic spination loosely arrayed in three instead of two rows and absence of the antennular basipodite and coxopodite spines. Observations on burrowing, ecological preferences and biology are presented.
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