There is growing recognition that agricultural biosecurity requires broadening of responsibility beyond governments. In Australia, this has led to the implementation of a shared responsibility approach that disperses biosecurity activity across public and private actors. Drawing on a qualitative study of 89 participants, we investigate scale challenges that emerged from participant reports of working within a shared responsibility framework and introduce the concept of scale work to reflect the strategies actors developed to navigate these challenges. In doing so, we address two questions: What scale challenges are constructed by participants engaging in biosecurity work within a shared responsibility framework? What forms of scale work do biosecurity actors engage in to negotiate these challenges? Participants identified jurisdictional and role scale challenges as arising from conflicting regulatory frameworks and ambiguities surrounding roles and responsibilities, both of which have the potential to undermine shared biosecurity efforts. Rather than viewing these tensions as evidence of policy failure, we argue that they are a natural consequence of multi-actor governance arrangements that actors negotiate through scale work such as workarounds and coalition building. These examples reflect two forms of scale work: adaptive scale work to align conflicting regulatory frameworks, and integrative scale work to align actors across scales to facilitate collaborative approaches to biosecurity. In examining scale work, we argue that the shared responsibility approach to biosecurity in Australia is sustained through trust-based relational practices and rendered workable through actors' continual efforts to negotiate the scale challenges that arise within such governance arrangements.
Microplastic contamination and associated polymer toxicity in mollusks are emerging concerns for ecosystem health and seafood safety in coastal environments. This study compares microplastic abundance, polymer composition, and exposure risks in wild and cultured populations of Crassostrea madrasensis, Perna viridis, and Telescopium telescopium from coastal Bangladesh. Microplastics were detected in all species, with mean abundances ranging from 0.68 ± 0.22 to 1.12 ± 0.10 items g−1. Fibres dominated, accounting for 77 to 94% of particles, with most measuring less than 500 μm. Transparent and violet particles were most common, indicating sources from textiles, ropes, and aquaculture materials. Polymer composition was determined using Fourier-transform infrared (FTIR) with PE, PET, PS, EVA, Nylon, and PVA identified among the detected polymers. Polymer hazard index values were similar across groups (PHI 15.7–18.7, level II), whereas MPERI was higher in cultured than wild Crassostrea madrasensis (18.6 vs 16.1) but lower in cultured than wild Perna viridis (7.1 vs 17.7). Estimated human intake through mollusk consumption ranged from 0.28 to 0.47 items kg−1 day−1, corresponding to 6.2 × 103 to 1.0 × 104 items per person per year. The dominance of fine fibres and the presence of higher hazard polymers indicate potential chronic ecological stress and food safety concerns. These findings emphasize the need for improved aquaculture practices and targeted monitoring in coastal Bangladesh.
Context Rice-based double-cropping systems are increasingly challenged by seasonal waterlogging and climate change, yet the long-term implications of winter crop selection for whole-system performance remain poorly understood. Objective To quantify the relative importance of winter crop selection and future climate change in determining the productivity, resource-use efficiency and resilience of rice-based cropping systems. Methods An improved APSIM framework was developed and evaluated using multi-year field observations from four rice-based crop rotations. The validated model was applied under historical climate and three 2050s climate scenarios, and system performance was assessed using agronomic, economic and environmental indicators. Results and conclusions Interannual climate variability had the greatest influence on system yield in the 2050s, explaining 65.6% of total variance, while crop type explained 37.3% of cumulative waterlogging-stress variance. Rice–wheat was consistently the most vulnerable rotation, with waterlogging-induced yield penalties increasing from 5.9% under the historical climate to 9.8% under SSP585. Rice–faba bean showed the most balanced multidimensional performance, combining strong waterlogging resilience, high simulated profitability, high fertiliser-based nitrogen use efficiency and low greenhouse gas intensity. Waterlogging also increased nitrogen losses and N2O emissions while reducing nitrogen use efficiency, particularly in the rice–wheat and rice–canola rotations. Significance This study shows that crop selection and climate variability influence different dimensions of rice-based system performance. Although annual productivity was strongly affected by interannual climate variability, winter crop selection substantially influenced seasonal waterlogging stress and the comparative performance of alternative rotations. The findings support crop diversification as an adaptation strategy for regions facing increasing waterlogging risk.
The rapid integration of inverter-based resources (IBRs) is changing the dynamic behaviour of modern power systems. As synchronous generators are replaced by photovoltaic (PV) inverters, system inertia decreases and frequency stability becomes more difficult to maintain.This paper compares proportional-integral (PI) control and sliding mode control (SMC) for PV inverter regulation in an IEEE 9-bus test system. Synchronous generators are progressively replaced by PV inverters to represent low and high IBR penetration levels. In both cases, active power sharing is provided through frequency-based droop control.Four MATLAB/Simulink scenarios are studied under 10% and 15% load disturbances. The results show that PI control provides smoother and better-damped responses under low IBR penetration. However, its performance deteriorates when penetration level and disturbance magnitude increase. In contrast, SMC improves the frequency nadir and shortens the recovery time under high-penetration and large-disturbance conditions.These findings show that PI and SMC have complementary operating characteristics. PI is more suitable for moderate operating conditions, while SMC provides stronger robustness in low-inertia scenarios. The results provide practical guidance for controller selection in renewable-dominated power systems.
With increasing global ecosystem degradation, new ways of governing the relationship between people and nature are needed. As Western societies increasingly turn to the emerging practice of Natural Capital Accounting (NCA), this is a critical time to consider its institutional role. In this paper we consider the effectiveness of NCA in bringing accountability for nature. This study theorises the link between accountability and NCA practice and explores this link empirically through quantitative and qualitative analyses of four methods of practice - the Capitals Coalition, Integrated Reporting, the System of Environmental Economic Accounting – Ecosystem Accounting, and Accounting for Nature®. The study found that NCA methods employ a range of technical mechanisms for delivering accountability, including data processes, external audit, and participation of, and transparency with, stakeholders; however, there were substantial limitations for their effectiveness. Our results highlight five challenges for NCA in delivering accountability for nature, underpinned by the broader governance environment in which this institution operates. We discuss governance options for bringing accountability for nature both with, and without, NCA. The findings of this study will help academics and policy makers to design institutional arrangements which are fit-for-purpose for bringing accountability for nature.
