Michael Renton

Summary: Seed traits underpin plant regeneration and are central to predicting species' responses to environmental change, yet their intraspecific variability remains poorly integrated into trait‐based frameworks. Progress has been limited by the conflation of processes operating across nested levels, from regions and populations to mother plants and individual seeds, and by weak integration of genetic drivers with environmental and phenotypic data. Drawing on published literature and analyses of seed traits in wild tree populations, we show that substantial seed‐trait variation can occur among mother plants and individual seeds within populations, meaning that population‐level macroenvironmental variables often capture only part of the observed variation. To address these limitations, we propose a roadmap to disentangle hierarchical drivers of intraspecific trait variability (ITV) in seeds. We outline a strategic plan to quantify seed‐trait variation across hierarchical levels, investigate its drivers where variation is concentrated, and assess its consequences for recruitment and demographic outcomes. We recommend coordinated, standardised sampling and experiments that retain mother‐plant and individual‐seed identity, integrate genetic, environmental and phenotypic data, and use scalable approaches to link seed traits to performance across recruitment stages. Recognising and integrating ITV across nested levels is essential for improving predictions of plant regeneration under environmental change.

Background: Spatially targeted spraying is an alternative to broadcast herbicide application that reduces herbicide use by restricting treatment to areas where weeds are detected. However, weed detection using remote or proximal sensing and classification algorithms is imperfect, which may allow weeds to escape treatment. This study examined the evolutionary consequences of spatially targeted spraying and evaluated whether applying herbicide to spray‐buffer zones surrounding detected weeds could compensate for reduced detection accuracy. We tested two hypotheses: first, that spray‐buffer zones can offset imperfect weed detection; and second, that lower detection accuracy and smaller spray‐buffer zones accelerate crop failure, by increasing weed survival, resistance evolution and population growth. Results: A new spatially explicit simulation model was used to represent weed populations with defined genetic architectures conferring different levels of herbicide resistance. The simulation results supported the first hypothesis, showing that spray‐buffer zones reduced the proportion of weeds escaping treatment under imperfect detection. However, the second hypothesis was not supported. More‐accurate spraying removed susceptible weeds more effectively but also imposed stronger selection for herbicide resistance. By contrast, less‐accurate detection resulted in larger weed populations, maintained a higher proportion of susceptible genotypes, and slowed the evolution of resistance. Conclusion: Spray‐buffer zones can partly compensate for imperfect weed detection in spatially targeted spraying systems. However, improving spray precision does not necessarily delay future crop failure from weed competition, because stronger short‐term control may accelerate resistance evolution. These findings highlight an important trade‐off between immediate herbicide efficacy and the long‐term durability of weed management strategies. They also underscore the importance of diversifying weed management strategies alongside the development of more‐accurate targeted herbicide application technologies. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Despite decades of research, fundamental gaps remain in our understanding of coral vital rates across taxa. This is particularly true for the early life stages, which are critical for reef recovery, representing significant bottlenecks to population growth. We assessed the survival of 3334 small corals (0.3–10 cm maximum diameter) across four eastern Indian Ocean reefs through contrasting levels of heat stress. Under background conditions at multiple reefs, survival of small corals ranged between 0.43 and 0.92 yr ⁻¹ and increased with colony size. Following a major heat stress event (13 Degree Heating Weeks (°C-weeks)), which caused moderate bleaching at Ashmore Reef, survival was comparable to background levels (0.67 yr ⁻¹ HDI: 0.57–0.77). In contrast, major heat stress at Mermaid Reef (11 °C-weeks) in the same period caused severe bleaching and substantially reduced survival to 0.21 (6 _mo ) ⁻¹ (HDI: 0.10–0.32). This was associated with a collapse of size-dependent survival for structurally complex, bleaching-susceptible taxa ( Acropora, Pocillopora ). Stress-tolerant taxa ( Goniastrea, Porites ) experienced smaller reductions in survival and retained size-specific survival patterns. Spanning multiple reefs under varying levels of heat stress, this study provides taxa- and size-specific insights for improving predictions of coral population trajectories and informing reef management and restoration strategies under future climate scenarios.

Summary: The mutualism between mycorrhizal fungi and plants has persisted for over 400 million years, despite the mutualism paradox predicting that mutualisms should be evolutionarily unstable due to the fitness advantages of cheating. It is widely accepted that mutual benefit alone is not sufficient for stable mutualism, and so a search for additional stabilising mechanisms has been the focus of past investigation. In this work, we test the assumption that cheating is an omnipresent threat to mutualism; hence, additional mechanisms for stability are needed. We developed a novel individual‐based model of a plant and mycorrhizal fungus, where mechanisms commonly thought necessary for mutualism stability, for example, partner choice, are absent. The organisms take up carbon and phosphorus at different uptake efficiencies, exchange resources, and grow depending on their limiting resource over 10 time steps. We simulated co‐evolution of resource trading strategies over 2000 generations, under 231 nutrient uptake efficiency combinations. Evolutionarily stable mutualism evolved in 66% of the nutrient uptake efficiency combinations tested. Parasitism and Darwinian extinction also occurred. Our results suggest that different nutrient uptake efficiencies, Leibig's law of the minimum, and one‐to‐one resource trade are sufficient to explain stable mutualism, parasitism and Darwinian extinction, via fitness feedback, without additional mechanisms.

Earth's most complex and biodiverse ecosystems are characterised by high habitat complexity. On coral reefs, habitat complexity is influenced by the diverse morphology and composition of hard corals, shaping reef structure and shelter provision for many species. Various metrics are used to quantify reef complexity, yet, it remains unclear how well these metrics capture ecological functions such as shelter provision. We used a published dataset of 13 distinct coral community types generated using a 3D functional–structural model to investigate the redundancy, complementarity and ecological relevance of 11 habitat complexity metrics (seven ecologically meaningful shelter metrics and four more general structural metrics). We were especially interested in the extent to which structural metrics predicted shelter metrics, potentially reducing the need for more complicated and direct shelter measurements. We used Pearson's correlations to compare metrics in (i) one pooled analysis from all community types, and (ii) 13 individual analyses for each community type. In the pooled analysis, structural metrics were strongly correlated, while the shelter metrics formed two distinct groups—‘pelagic’ and ‘benthic.’ Within these groups, the metrics were highly correlated indicating redundancy, but between groups, they showed weak correlations indicating complementarity. For individual community types, the redundancy or complementarity of these metrics varied with coral morphology. Structural metrics were useful predictors of shelter metrics for certain community types; for example, surface rugosity was a strong predictor of shelter volume for tabular and digitate coral communities but not for other communities. Fractal dimension was highly complementary to other metrics, but further investigation is needed to identify its ecological relevance. We highlight that there is no universal metric, and it is important to consider a range of suitable habitat complexity metrics and morphological community composition for ecosystems with morphologically distinct biogenic habitat formers.

We aimed to (i) develop a new computational functional–structural plant root model (FSPM) able to represent a wide range of realistic root system structures and growth strategies with varying levels of phenotypic plasticity while being flexible and efficient enough to facilitate our longer term objective of simulating plant populations or communities interacting and evolving over many generations in different conditions and (ii) use this model to study the evolution of root architecture and plasticity in environments with different levels of soil heterogeneity and rainfall frequency. A model was designed to meet the requirements above. We successfully tested the new model by using it together with an evolutionary algorithm to simulate the evolution of populations of plants with asexual reproduction growing independently. Our model was able to represent realistic root system structures and growth strategies while being flexible and efficient enough to simulate plant populations or communities interacting and evolving over many generations in different conditions. Over evolutionary generations, structural root growth strategies developed and overall fitness (measured as shoot biomass) improved. Different strategies evolved in different evolutionary runs and in different conditions. Evolution clearly selected for root branching plasticity in response to increased local soil water content, indicating that this plasticity confers fitness benefits due to increased water uptake. We conclude that dynamic evolutionary FSPMs have the potential to help us understand the eco-evolutionary costs and benefits of different functional–structural growth strategies. Spatial and temporal heterogeneity in water availability causes the evolution of contrasting root architectures, with different levels of plasticity.

Coral reefs are complex three-dimensional habitats where the sizes, shapes, diversity and composition of hard corals influence the overall reef structure, and thus the provision of shelter for reef-associated species such as fish. Various metrics have been used to quantify ‘habitat complexity’ on coral reefs, yet debate persists regarding the most informative metric and how effectively the available metrics capture ecologically meaningful functions such as shelter provision. We used Coralcraft, a three-dimensional mechanistic model, to investigate how the morphological diversity and composition of coral communities influences habitat complexity at local (metres) scales. We developed new metrics of shelter to capture the mechanisms by which structure is likely important to reef species, accounting for factors such as the size of predator and prey and different hunting strategies. We simulated the growth of 13 coral community types with varying compositions of 10 common coral morphologies, calculating coral cover and 10 habitat complexity metrics (six novel and four well-established) over a five-year period. We found that more diverse coral communities did not always have the greatest structural complexity and shelter, in part due to certain morphologies having disproportionate influence on the resulting habitat complexity. Communities with lower structural complexity did not necessarily provide less shelter. The relationship between coral cover and habitat complexity metrics varied widely between different communities and was often nonlinear. We conclude that accounting for the morphological composition of coral communities can vastly improve the ability to predict or infer habitat complexity—both structural complexity and shelter provision—from measures of coral cover.

BACKGROUND: Globally the spread of invasive pests is being facilitated by increased human mobility and climate change. Simulation modelling can help assess biosecurity strategies for early detection and rapid response (EDRR), but has struggled to account for important factors in the invasion process, such as spatial and temporal variability in habitat suitability and connectivity; population dynamics; and multiple dispersal pathways.We developed a novel dynamic spatial network simulation approach based on spatial network theory that enables integration of a wider range of spatio‐temporal factors than previous studies, calibrated it against extensive historical trapping data, and applied it to comprehensively analyse the EDRR strategy for Oriental fruit fly (Bactrocera dorsalis; OFF) in northern Australia.RESULTS: Simulations indicated that the chance of OFF reaching the mainland in the next 20 years could be up to 20% under the current EDRR strategy, depending on how optimistic or pessimistic model assumptions are, and highlighted possible improvements to the EDRR strategy for further consideration. Simulations under optimistic assumptions indicate that transport via wind is most important in OFF reaching the mainland, but under pessimistic assumptions transport via people carrying infected fruit becomes more important.CONCLUSION: Our new dynamic spatial network simulation approach can account for a wide range of spatio‐temporal ecological factors to provide practical real‐world recommendations. At a minimum, this approach only requires weather and population data, both of which are available globally from a variety of free and open sources, making it broadly applicable to assessing the EDRR strategies in place for different species in other locations. © 2024 Society of Chemical Industry.

Marri (Corymbia calophylla), an endemic and keystone tree species of southwest Western Australia (SWWA), provides significant environmental, conservation, economic and cultural values. This study aims to analyse the effect of stand density, manipulated through thinning, on growth and allometry of marri-dominated forest. Although individual tree diameter (DHBUB, diameter at breast height under bark), basal area, height and crown-width (CW) growth was stimulated by thinning, stand basal-area growth was highest in denser (less thinned) stands. Stand density had a significant effect on the allometry between DBHUB and each of height and height-diameter ratio (HDR). Height and CW increased with an increase in DBHUB although the relationship with CW was not statistically significant; HDR was inversely related to DBHUB. Thinning has the potential to increase yields of merchantable timber, firewood, and enhance ecological values including tree hollows for arboreal fauna and marri-fruit production (important for cockatoos) that depend on retention of sufficient large old trees. Reduction of stand density through thinning reduces inter-tree competition and may help in reducing the risk of marri canker disease.