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The health of Corymbia calophylla (marri), a keystone tree species in the native forests of southwest Western Australia, has been in decline for the past few decades. Phytophthora root disease and waterlogging have often been cited as contributing to this decline. Traditional methods (i.e., field surveys and sampling) of mapping Phytophthora root infection in the field are time-consuming and expensive; thus, the potential of reflectance spectroscopy to characterize marri response to Phytophthora and waterlogging stress was investigated. Twelve-month old marri plants were infected with either P. cinnamomi or P. multivora in two glasshouse trials and waterlogged for 24 h each fortnight. Spectral measurements with a portable high-resolution spectroradiometer were taken weekly. Plant biophysical measurements were taken at harvest time. Normalized difference spectral index (NDSI) was calculated for every combination of reflectance values between 400 and 2500 nm for all time points, correlated with the treatment effects and displayed as heat maps. Narrowband vegetation indices (VIs), utilizing different wavelengths of the electromagnetic spectrum, were also calculated from the spectral data. The Phytophthora treatments did not cause significant differences with the biophysical measurements in both trials. In the second trial, the waterlogging treatment significantly lowered plant top dry weight (P = 0.016) and diameter (P = 0.044). Reflectance values plotted against wavelength displayed differences between treatments as well as a seasonal trend. The NDSI heat maps indicated that the Phytophthora and waterlogging treatment effects were strongest correlated with bandwidths in the visible and near-infrared portions of the electromagnetic spectrum (538–558 nm and 701–709 nm). Six of the VIs (normalized difference nitrogen index 2, anthocyanin reflectance index 1, photochemical reflectance index, Carter index 1, Vogelman index 3 and water band index) were able to track the biochemical changes in the leaves over the 10 weeks, confirming the seasonal trend. The interaction effect between P. cinnamomi, waterlogging and elapsed time in the first trial was significant for water band index (P = 0.010). This study demonstrates that reflectance spectroscopy holds promise for characterizing marri response but more work needs to be done to identify the optimum wavelengths for identifying Phytophthora and waterlogging stress with marri.

The viability of forest trees, in response to climate change-associated drought, will depend on their capacity to survive through genetic adaptation and phenotypic plasticity in drought tolerance traits. Genotypes with enhanced plasticity for drought tolerance (adaptive plasticity) will have a greater ability to persist and delay the onset of hydraulic failure. By examining populations from different climate-origins grown under contrasting soil water availability, we tested for genotype (G), environment (E) and genotype-by-environment (G × E) effects on traits that determine the time it takes for saplings to desiccate from stomatal closure to 88% loss of stem hydraulic conductance (time to hydraulic failure, THF). Specifically, we hypothesized that: (i) THF is dependent on a G × E interaction, with longer THF for warm, dry climate populations in response to chronic water deficit treatment compared with cool, wet populations, and (ii) hydraulic and allometric traits explain the observed patterns in THF. Corymbia calophylla saplings from two populations originating from contrasting climates (warm-dry or cool-wet) were grown under well-watered and chronic soil water deficit treatments in large containers. Hydraulic and allometric traits were measured and then saplings were dried-down to critical levels of drought stress to estimate THF. Significant plasticity was detected in the warm-dry population in response to water-deficit, with enhanced drought tolerance compared with the cool-wet population. Projected leaf area and total plant water storage showed treatment variation, and minimum conductance showed significant population differences driving longer THF in trees from warm-dry origins grown in water-limited conditions. Our findings contribute information on intraspecific variation in key drought traits, including hydraulic and allometric determinants of THF. It highlights the need to quantify adaptive capacity in populations of forest trees in climate change-type drought to improve predictions of forest die-back.

Diseases caused by pathogens, alone or in combination with other stress factors, are a major threat to the future health of urban forests. Root diseases caused by Phytophthora species are frequently evident in urban environments due to conducive environments for these pathogens, and to conditions predisposing trees to attack. Urban environments are also an important pathway for the introduction of Phytophthora species into novel ecosystems. We have detected many different Phytophthora species from dying and declining trees in the urban and peri-urban environment, and for many of these species, little is known about their host range. Therefore, the aim of this study was to examine the host range of 19 Phytophthora species, including many recently described species, against fifteen tree species commonly used in urban plantings in Perth, Western Australia. Excised branches of each tree species were under-bark inoculated with each Phytophthora species, incubated and lesions were measured after 8 days. Six Phytophthora species were pathogenic to all fifteen-tree species, with ~75% of the species each causing disease in ≥85% of plant hosts. All Phytophthora species formed lesions in Eucalyptus marginata and Corymbia calophylla. Phytophthora cinnamomi, P. pseudocryptogea, and P. citrophthora were the most pathogenic species causing the largest lesions in most of these trees species. It is likely many of these Phytophthora species have a negative impact on the health of urban forests where they are present.

Global shifts in climate and precipitation patterns are altering the diversity and structure of forests. The ability for species to adapt is especially difficult for long lived foundation species with unknown genetic and trait diversity. We harnessed genomic, physiological, and climate data to determine adaptation constraints. We used denovo assembly and 6.5 million genomic variants with drought related traits from 432 individuals sourced from across the complete range of the foundation tree speciesCorymbia calophylla. We found genomic variants determining traits predominantly in gene regulatory regions. The ability for populations to adapt was limited by within population genetic diversity associated with traits, and epistatic interactions within traits and pleiotropic interactions among traits. Nevertheless, we could accurately predict adaptive traits using genomic and climate data to guide reforestation. Our study indicated that some populations may contain variation sufficient for the species to adapt to the effects of drought, while other populations will need increased variability from those sources.

Worldwide, extreme climatic events such as drought and heatwaves are associated with forest mortality. However, the precise drivers of tree mortality at individual and stand levels vary considerably, with substantial gaps in knowledge across studies in biomes and continents. In 2010–2011, a drought‐associated heatwave occurred in south‐western Australia and drove sudden and rapid forest canopy collapse. Working in the Northern Jarrah (Eucalyptus marginata) Forest, we quantified the response of key overstory (E. marginata, Corymbia calophylla) and midstory (Banksia grandis, Allocasuarina fraseriana) tree species to the extreme climate event. Using transects spanning a gradient of drought impacts (minimal (50–100 m), transitional (100–150 m) and severe (30–60 m)), tree species mortality in relation to stand characteristics (stand basal area and stem density) and edaphic factors (soil depth) was determined. We show differential mortality between the two overstory species and the two midstory species corresponding to the drought‐associated heatwave. The dominant overstory species, E. marginata, had significantly higher mortality (~19%) than C. calophylla (~7%) in the severe zone. The midstory species, B. grandis, demonstrated substantially higher mortality (~59%) than A. fraseriana (~4%) in the transitional zone. Banksia grandis exhibited a substantial shift in structure in response to the drought‐associated heatwave in relation to tree size, basal area and soil depth. This study illustrates the role of climate extremes in driving ecosystem change and highlights the critical need to identify and quantify the resulting impact to help predict future forest die‐off events and to underpin forest management and conservation.

In forest ecosystems, habitat fragmentation negatively impacts stand structure and biodiversity; the resulting fragmented patches of forest have distinct, disturbed edge habitats that experience different environmental conditions than the interiors of the fragments. In southwest Western Australia, there is a large-scale decline of the keystone tree species Corymbia calophylla following fragmentation and land use change. These changes have altered stand structure and increased their susceptibility to an endemic fungal pathogen, Quambalaria coyrecup, which causes chronic canker disease especially along disturbed forest habitats. However, the impacts of fragmentation on belowground processes in this system are not well-understood. We examined the effects of fragmentation on abiotic soil properties and ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungal communities, and whether these belowground changes were drivers of disease incidence. We collected soil from 17 sites across the distribution range of C. calophylla. Soils were collected across a gradient from disturbed, diseased areas to undisturbed, disease-free areas. We analysed soil nutrients and grew C. calophylla plants as a bioassay host. Plants were harvested and roots collected after 6 months of growth. DNA was extracted from the roots, amplified using fungal specific primers and sequenced using Illumina MiSeq. Concentrations of key soil nutrients such as nitrogen, phosphorus and potassium were much higher along the disturbed, diseased edges in comparison to undisturbed areas. Disturbance altered the community composition of ECM and AM fungi; however, only ECM fungal communities had lower rarefied richness and diversity along the disturbed, diseased areas compared to undisturbed areas. Accounting for effects of disturbance, ECM fungal diversity and leaf litter depth were highly correlated with increased disease incidence in C. calophylla. In the face of global change, increased virulence of an endemic pathogen has emerged in this Mediterranean-type forest.

Recent studies have shown that in the spectral space there is often a better spectral separation between leaves and flowers and even between flowers of different species than between leaves of different species. In this study we assess the ability of satellite remotely sensed data to detect the flowering of Red Gum trees (Corymbia calophylla) in Western Australia, the state’s largest annual honey crop. Spectroradiometer measurements of flowers, leaves and groundcover from Red Gum forests were subjected to ANOVA analysis, which showed that flowers are spectrally different to their environment for 92 % of the wavelengths between 350 nm and 1800 nm. A more detailed assessment, using the JM Distance calculation, showed that the spectra can be reliably separated using 10 % of the wavelengths, with peak separation between 518 nm and 557 nm. To assess the ability of satellite-borne sensors to detect the presence of flowers, the spectroradiometer data were convolved with satellite instruments’ response curves to create synthetic remotely sensed datasets on which JM Distance analysis was performed. MODIS blue bands achieved a median JM Distance of greater than 1.9 and therefore should be able to detect the presence of flowers from the environment. Further assessment showed that the shortest wavelength bands for MODIS, VIIRS and Sentinel 3 all occur where the flower spectra have lower reflectance than their natural background. A sensitivity analysis of percentage flower cover for a pixel showed that the highest sensitivity was obtained by dividing the band closest to 520 nm by the shortest wavelength band for data from these three sources. The MODIS band 10/band 8 metric was tested for its ability to detect flowers in real-world data using 15 years of qualitative honey harvest data from one apiary site as a proxy for flower density. This test was successful as, while there was some overlap between good, moderate and poor years, the poor years could be separated from the other years with nearly 80 % accuracy.

With Apis mellifera (the European Honey Bee) having an average forage radius of less than one kilometre from their hive, selecting the best location for beehives is critical for commercial beekeepers to optimise their honey production. In this study, we have used standard three-band digital cameras to develop and assess a simple parallelpiped algorithm to detect the flowers of the Corymbia calophylla tree in Western Australia, the largest source of honey in the state. The algorithm has been tested in a number of situations and, within the bounds of the study, works to a better than 90% classification accuracy for Digital Single Lens Reflex camera images of trees within 15 m distance, and often better than 95%. To determine how this approach could be used by Unmanned Aerial Vehicle platforms to detect flowering Corymbia calophylla flowering, image resolution was progressively degraded until flowers could not be detected. It was found that the cluster size of flowers (i.e. whether flowers occur individually or in groups) played an important role in determining the accuracy of flower detection, but overall a minimum resolution of 10 pixels per flower is required for reliable detection of flower pixels. While there is some improvement above this resolution, the effect is minimal. The key to accurate measurement of percentage flower cover is the accuracy of the classification of the background. If the background classification error is known for an image or scene, the percentage flower cover can be calculated with as little as 2% flower cover. Based on this study, UAV platforms with standard RGB cameras appear to be suitable for detection of Corymbia calophylla flowers if surveys are designed within the bounds described. Thus, UAV surveys may prove to be useful for beekeepers to optimise the location of their beehives amongst a choice of different locations.

Bioturbation is an important ecosystem process, and the loss of native digging mammals due to introduced predators and habitat loss may have detrimental consequences for ecosystem health. The mycophagous woylie (Bettongia penicillata ogilbyi) was once widespread across the Australian continent and currently exists in a greatly reduced range, while the omnivorous quenda (Isoodon fusciventer), which once occurred across the southern part of Western Australia (WA), remains common in south west WA over a reduced range. Populations of these two digging marsupials are currently maintained within sanctuaries where they can reach high densities. To assess the influence these digging marsupials have on fungal assemblages, we investigated fungal root associations among seedlings of a key mycorrhizal forest canopy species, Corymbia calophylla, R. Br. K. D. Hill and L. A. S. Johnson. Seedlings were grown in soil collected from inside (heavily-dug soil) and outside (minimally-dug soil) two predator-proof sanctuaries. Our results showed that above-ground seedling biomass was significantly greater for seedlings grown in soil collected from inside the sanctuaries. There were no differences in the diversity or species richness of rhizosphere fungal communities isolated from these seedlings; however, the community composition was significantly different. This was most obvious for the predator-proof enclosure that had been in place for 20 years (Karakamia Sanctuary) compared with the more recently-installed Perup Sanctuary (fenced in 2010; 4 years before this study). At Karakamia, there were greater numbers of putatively hypogeous ectomycorrhizal fungi inside the enclosure and four times the number of operational taxonomic units of arbuscular mycorrhizal fungi outside the enclosure. The differences in fungal communities suggest that digging mammals play a pivotal role in ecosystem functioning by influencing the rhizosphere of this key forest canopy species, which has implications for maintaining the health and persistence of forests.

The pathogenicity of some Phytophthora species recently described from Western Australia, together with P. cinnamomi as a control, was tested against seven Western Australian native plant species in the glasshouse. Host species were Banksia grandis, B. littoralis, B. occidentalis, Casuarina obesa, Corymbia calophylla, Eucalyptus marginata and Lambertia inermis. Twenty-two Phytophthora species were grown on a vermiculite, millet seed and V8 substrate and used as soil inoculum when the plant hosts were approximately 3 months old. Pathogenicity was assessed after 6 weeks and plants were scored for death, root damage, and percentage reduction of shoot growth compared with control plants. The pathogenicity of P. cinnamomi was confirmed. Phytophthora niederhauserii was shown to be similar to P. cinnamomi in pathogenicity and of concern ecologically. Other species that killed one or more hosts were P. boodjera, P. constricta, P. elongata, P. moyootj and P. rosacearum, while P. condilina, P. gibbosa, P. gregata, P. litoralis and P. 'personii' caused significant reduction to shoot and/or root growth, but did not kill plants. Host species susceptible to the highest number of Phytophthora species were B. grandis, B. littoralis, B. occidentalis and E. marginata. No Phytophthora species tested killed C. calophylla.

The application of fertiliser, to both replace nutrients lost during mining and facilitate rapid vegetation re-establishment, is viewed as a key step in the restoration of post-mining landscapes. However, few studies have examined the long-term effects of a single initial fertiliser application on tree growth in restored sites. We report on a large-scale, fully replicated study that investigated the effect of an initial N and P fertiliser application (0, 80 and 120 kg ha−1 elemental N and P) on sites restored after bauxite mining. Growth of the two main jarrah forest tree species (jarrah - Eucalyptus marginata and marri - Corymbia calophylla) was monitored 9 and 20 years after the completion of restoration. After 20 years, soil NO3− and NH4+ were unaffected by N-application, although soil Colwell-P concentrations remained elevated following P-application. N-application had no effect on marri growth at either time interval, but increased jarrah diameter at breast height over bark (DBHOB), height and stand basal area at 9 years and DBHOB at 20 years. Applied-P increased height and DBHOB of jarrah after 9 years, but these effects did not continue. In contrast, applied-P benefitted marri growth (DBHOB and stand basal area) at both 9 and 20 years. Tree growth rates in the fertilised treatments declined more between the two-time intervals (0 – 9 years and 9 – 20 years) than the unfertilised plots, particularly for jarrah, suggesting that resource limits were reached more rapidly in the fertilised treatments. Further, for both N and P there was no additional benefit from application rates above 80 kg ha−1. These results demonstrate that while fertiliser addition may benefit initial growth in restored jarrah forest, the effects reduce with restoration age and may have limited practical benefit after 20 years.

During routine surveys of Corymbia calophylla, a widespread tree currently experiencing decline over a large area of its native range of south west Western Australia, a slow growing Phytophthora species was often recovered from roots and rhizosphere soil. This species grew more slowly, produced a wide array of morphological features and was visibly different to all other Phytophthora species present in Western Australia. Phylogenetic analyses of the ITS, cox1, HSP90, β-tubulin and NADH gene regions confirmed this to be a new species closely related to P. quercina and the provisional species P. ‘ohioensis’. The new species is described here as Phytophthora versiformis sp. nov. It produces persistent, papillate sporangia of variable shape, oogonia with thick-walled oospores, and paragynous antheridia. To date this species has only been recovered from C. calophylla. Pathogenicity trials indicate that while P. versiformis can infect the roots of C. calophylla it does not lead to seedling death.

Short-term acclimation and long-term adaptation represent two ways in which forest trees can respond to changes in temperature. Yet, the relative contribution of thermal acclimation and adaptation to tree physiological responses to temperature remains poorly understood. Here, we grew two cool-origin and two warm-origin populations of a widespread broad-leaved evergreen tree species (Corymbia calophylla (Lindl.) K.D.Hill & L.A.S.Johnson) from a Mediterranean climate in southwestern Australia under two growth temperatures representative of the cool- and warm-edge of the species distribution. The populations selected from each thermal environment represented both high and low precipitation sites. We measured the short-term temperature response of leaf photosynthesis (A) and dark respiration (R), and attributed observed variation to acclimation, adaptation or the combination of both. We observed limited variation in the temperature optimum (Topt) of A between temperature treatments or among populations, suggesting little plasticity or genetic differentiation in the Topt of A. Yet, other aspects of the temperature response of A and R were dependent upon population and growth temperature. Under cooler growth temperatures, the population from the coolest, wettest environment had the lowest A (at 25 °C) among all four populations, but exhibited the highest A (at 25 °C) under warmer growth temperatures. Populations varied in R (at 20 °C) and the temperature sensitivity of R (i.e., Q10 or activation energy) under cool, but not warm growth temperatures. However, populations showed similar yet lower R (at 20 °C) and no differences in the temperature sensitivity of R under warmer growth temperatures. We conclude that C. calophylla populations from contrasting climates vary in physiological acclimation to temperature, which might influence how this ecologically important tree species and the forests of southwestern Australia respond to climate change.

The ability of plants to maintain an intact water transport system in leaves under drought conditions is intimately linked to survival and can been be seen as adaptive in shaping species climatic limits. Large differences in leaf hydraulic vulnerability to drought are known among species from contrasting climates, yet whether this trait varies among populations within a single species and, furthermore, whether it is altered by changes in growth conditions, remain unclear. We examined intraspecific variation in both leaf water transport capacity (Kleaf) and leaf hydraulic vulnerability to drought (P50leaf) among eight populations of Corymbia calophylla (R. Br.) K.D. Hill & L.A.S. Johnson (Myrtaceae) from both cool and warm climatic regions grown reciprocally under two temperature treatments representing the cool and warm edge of the species distribution. Kleaf did not vary between cool and warm-climate populations, nor was it affected by variable growth temperature. In contrast, population origin and growth temperature independently altered P50leaf. Using data pooled across growth temperatures, cool-climate populations showed significantly higher leaf hydraulic vulnerability (P50leaf = -3.55 ± 0.18 MPa) than warm-climate populations (P50leaf = -3.78 ± 0.08 MPa). Across populations, P50leaf decreased as population home-climate temperature increased, but was unrelated to rainfall and aridity. For populations from both cool and warm climatic regions, P50leaf was lower under the warmer growth conditions. These results provide evidence of trait plasticity in leaf hydraulic vulnerability to drought in response to variable growth temperature. Furthermore, they suggest that climate, and in particular temperature, may be a strong selective force in shaping intraspecific variation in leaf hydraulic vulnerability to drought.

This paper explores the high-performance thin-layer chromatographic (HPTLC) fingerprinting of non-sugar constituents for the authentication of honeys using highly antibacterial Jarrah (Eucalyptus marginata) and Marri (Corymbia calophylla) honeys sourced from Western Australia, different Leptospermum-derived Manuka honeys, and a typical table honey from an undisclosed floral source as test samples. As is demonstrated in this study, using HPTLC fingerprinting, it is possible to define differences in botanical origin as the honey fingerprints exhibit a unique profile of bands (i.e., Rf values, color) and peak profiles (i.e., Rf and peak intensity values, peak intensity ratios) that differ distinctly from each other. The identification of patterns of common bands among honeys derived from the same floral source as authentication tool is possible. Further, slight differences among honeys from the same botanical origin might be due to age, processing, or regional factors. The HPTLC analysis of two differently a...

The antibacterial activity of honeys derived from the endemic flora of the southwest corner of Western Australia, including the trees Jarrah (Eucalyptus marginata) and Marri (Corymbia calophylla), remains largely unexplored. Investigation of these honeys showed minimum inhibitory concentrations (MICs) of 6.7–28.0% (w/v) against Gram positive and negative bacteria. Honey solutions showed enhanced antibacterial activity after hydrogen peroxide was allowed to accumulate prior to testing, with a mean MIC after accumulation of 14.3% compared to 17.4% before accumulation. Antibacterial activity was reduced after treatment with catalase enzyme, with a mean MIC of 29.4% with catalase compared to 15.2% without catalase. Tests investigating the role of the Gram negative outer membrane in honey susceptibility revealed increases in activity after destabilisation of the outer membrane. Honeys reduced both the formation of biofilm and the production of bacterial pigments, which are both regulated by quorum sensing. However, these reductions were closely correlated with global growth inhibition. Honey applied to existing biofilms resulted in decreased metabolic activity and minor decreases in viability. These results enhance our understanding of the mechanisms of antibacterial action of Jarrah and Marri honeys, and provide further support for the use of honey in the treatment of infected wounds.

Climate change is testing the resilience of forests worldwide pushing physiological tolerance to climatic extremes. Plant functional traits have been shown to be adapted to climate and have evolved patterns of trait correlations (similar patterns of distribution) and coordinations (mechanistic trade‐off). We predicted that traits would differentiate between populations associated with climatic gradients, suggestive of adaptive variation, and correlated traits would adapt to future climate scenarios in similar ways.We measured genetically determined trait variation and described patterns of correlation for seven traits: photochemical reflectance index (PRI), normalized difference vegetation index (NDVI), leaf size (LS), specific leaf area (SLA), δ13C (integrated water‐use efficiency, WUE), nitrogen concentration (NCONC), and wood density (WD). All measures were conducted in an experimental plantation on 960 trees sourced from 12 populations of a key forest canopy species in southwestern Australia.Significant differences were found between populations for all traits. Narrow‐sense heritability was significant for five traits (0.15–0.21), indicating that natural selection can drive differentiation; however, SLA (0.08) and PRI (0.11) were not significantly heritable. Generalized additive models predicted trait values across the landscape for current and future climatic conditions (>90% variance). The percent change differed markedly among traits between current and future predictions (differing as little as 1.5% (δ13C) or as much as 30% (PRI)). Some trait correlations were predicted to break down in the future (SLA:NCONC, δ13C:PRI, and NCONC:WD).Synthesis: Our results suggest that traits have contrasting genotypic patterns and will be subjected to different climate selection pressures, which may lower the working optimum for functional traits. Further, traits are independently associated with different climate factors, indicating that some trait correlations may be disrupted in the future. Genetic constraints and trait correlations may limit the ability for functional traits to adapt to climate change., We tested whether functional traits of an important tree species in southwestern Australia were genetically determined and able to undergo selection. Our results suggest that some traits are heritable (Water Use Efficiency) while others are not (SLA), indicating that in the future, under different climates, selection will differentially effect traits. Therefore, it is likely that current trait combinations will change with climate.

Trends of environmental change are influencing the behavior of many species across the world, while highly mobile species are disproportionately impacted by climate change and human modification. Here, we investigate the mechanisms behind climate change effects on the reproductive traits of highly mobile, West Australian bird taxa, the forest red‐tailed black cockatoo Calyptorhynchus banksii naso (FRTBC). Using a dataset of annual breeding frequency spanning 19 yr, in combination with hydrological, climatological, and remotely sensed data, we modeled the effects of environmental variation on the annual breeding frequency of FRTBCs. We found several significant relationships between annual breeding frequency of FRTBCs and environmental variation. While the model, which included a proxy for the availability of the cockatoo's primary food source and the previous season's rain, explained 49% of annual breeding frequency, there were also direct and indirect effects of heatwaves and forest productivity. Forest red‐tailed black cockatoo breeding appears to be linked to the spatiotemporal availability of its primary food sources, the fruit from the tree species, marri Corymbia calophylla and jarrah Eucalyptus marginata. However, Western Australia is experiencing significant climate change, with increases in temperature and declines in rainfall altering the phenologies of these species, while declining rainfall is affecting the vegetation structure of the region. As drought events and temperatures are anticipated to increase over the region, it is expected that the food resources during the breeding season for cockatoos will become increasingly limited in time and space, thus threatening the persistence of this iconic species. This scenario is likely to be representative of many other situations where wide‐ranging species rely on patchy food resources in a changing environment. As global biodiversity is increasingly threatened, this study presents timely evidence illustrating how climate change is affecting the persistence of a threatened, mobile species, and what the implications are for mobile species around the world.

Knowledge of flowering phenology is essential for understanding the condition of forest ecosystems and responses to various anthropogenic and environmental drivers. However, monitoring the spatial and temporal variability in forest flowering at landscape scales is challenging (e.g. current monitoring is often highly localized and in-situ or for single dates). This study presents a method that combines drone and satellite images (PlanetScope) that can produce landscape-scale maps of flowering dynamics. This method is demonstrated in forest landscapes dominated by the eucalypt Corymbia calophylla (red gum or marri) in Western Australia. Drone-derived images of flowering eucalypt canopies, available for restricted temporal and spatial extents, are used to label satellite image pixels with the proportion of a pixel footprint that is flowering. The pixels labelled with flowering proportion, the response variable, are combined with various metrics that characterize time series of spectral indices sensitive to the presence of green vegetation and cream-colored flowers, the predictor variables. A machine learning model then predicts daily pixel-level flowering proportions. The model is trained with data from two sites and is tested with data from three sites and various dates throughout the Corymbia calophylla season. The model is able to accurately predict pixel-level flowering proportion throughout the flowering season (RMSE

Questions: Climate change-type drought (the combination of drought and heatwave) has become a widely documented driver of forest dieback yet, to date, limited measurement of post-event forest dynamics has been reported. Can climate change-type drought trigger structural and/or compositional changes in a forest type which is usually highly resilient to other disturbances? Location: Mixed Eucalyptus forest in southwestern Australia. Methods: Forest areas that were severely and minimally affected by drought were measured repeatedly at 3, 6, 16, 26 and 49 mo post-event for changes in forest structure and composition of the two dominant tree species (Eucalyptus marginata/ Corymbia calophylla). Means and dispersal from pre-drought conditions were analysed for each structural variable among drought severity classes and between measurement periods. Resprouting, the predominant resilience mechanism in Eucalyptus, was assessed at 6 and 16 mo, while regeneration type and density were determined at 16 mo post-drought. Results: Structural changes were observed after 49 mo on plots severely but not minimally affected by drought, including a 30% increase in stem density (P < 0.0001) and reduction in tree diameter (23%; P < 0.01), basal area (33%; P < 0.0001), canopy height (40%; P < 0.0001) and live biomass (36%; P = 0.01). On severely affected plots, all structural variables plateaued at levels different from pre-drought conditions. Large, old trees on severely affected plots were replaced by high densities of small stems (1-10 cm DBH). Resprouting among drought affected trees (P < 0.001) and tree regeneration (P = 0.02) were higher on severely affected plots. No significant shifts in the proportional abundance of the two dominant species, E. marginata and C. calophylla, were observed for structural attributes or regeneration after 49 mo. Conclusion: Climate change-type drought can cause structural shifts in a resprouting mediterranean-type forest, providing evidence for a shift to an alternate state, particularly with repeated disturbance. While the study area showed low structural resistance and resilience, tree species composition was resilient to change, as E. marginata is likely to remain dominant in the future due to its resprouting capacity. Findings support the view that climate change-type drought will drive replacement of large trees with short, multi-stemmed individuals, transforming ecosystem structure

The attack patterns, infestation success and larval development of woodborers within living trees are complex and are largely shaped by host tree characteristics. Following a severe drought in a native eucalypt forest where outbreak densities of a native Australian beetle, the eucalyptus longhorned borer (Phoracantha semipunctata), occurred, a tree dissection study was conducted in Australia. This involved felling 40 trees each of jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) that were cut into 1-m sections and neonate larval galleries, larvae in pupal cells and adult borer emergence were measured and added to give total numbers per tree to determine the within-tree distribution and survival of P. semipunctata. There was a significant impact on larval survival in both species, in contrast, pupal survival remained high. Within-tree distribution of P. semipunctata was directional with borer emergence and incidence of larval galleries both negatively associated with tree section height above the ground and positively associated with section diameter and bark thickness, reaching a maximum towards the base of trees. High incidence and survival in lower thicker tree sections indicate a more conducive environment for larval development, in contrast to poor larval survival in smaller thinner sections at the top of trees. The dependence of larval survival on tree characteristics controlling the within-tree distribution of borer emergence is emphasized, and needs to be considered when estimating the spread of borer populations during outbreaks.

There is increasing concern about tree mortality around the world due to climatic extremes and associated shifts in pest and pathogen dynamics. Yet, empirical studies addressing the interactive effect of biotic and abiotic stress on plants are very rare. Therefore, in this study, we examined the interaction between drought stress and a canker pathogen, Quambalaria coyrecup, on the eucalypt – Corymbia calophylla (marri), which is experiencing increasing drought stress. We hypothesized that drought stress would increase marri’s susceptibility to canker disease, and cankers would have the largest negative effect on plants that are already drought stressed before pathogen inoculation. To test the hypotheses, in a glasshouse, marri saplings were exposed to drought either before or after pathogen inoculation, or were well-watered or droughted throughout the experiment either with or without inoculation. Canker development was greater in well-watered saplings than in droughted saplings, with the fastest development occurring in well-watered saplings that had experienced drought stress before inoculation. Irrespective of water treatments, marri saplings employed phenol-based localized biochemical defence against the pathogen. Drought reduced photosynthesis and growth, however, a negative effect of canker disease on saplings’ physiological performance was only observed in well-watered saplings. In well-watered saplings, canker-induced loss of sapwood function contributed to reduced whole-plant hydraulic conductance, photosynthesis and growth. The results provide evidence that timing of drought stress influences host physiology, and host condition influences canker disease susceptibility through differences in induced biochemical defence mechanisms. The observations highlight the importance of explicitly incorporating abiotic and biotic stress, as well as their interactions, in future studies of tree mortality in drought-prone regions worldwide.

We investigated the response of overstorey and mid-storey trees in tall open forest of Eucalyptus diversicolor F. Muell., Eucalyptus jacksonii Maiden, and Corymbia calophylla (Lindl.) K.D. Hill & L.A.S. Johnson over an eight-year period following complete crown scorch by high intensity fire in March 2001. More than 90% of E. diversicolor and E. jacksonii and 85% of C. calophylla remained alive four years after fire, having replaced their crowns by re-sprouting from epicormic buds on the stems and larger branches. Mid-storey trees were more severely affected by fire with almost one third of Allocasuarina decussata (Benth.) L.A.S. Johnson stems and all above-ground stems of Agonis flexuosa (Willd.) Sweet killed back to ground level. Abundant seedling regeneration of E. diversicolor and E. jacksonii developed in the year following the fire but seedling density and stocking declined progressively over subsequent years. Survival of E. diversicolor seedlings was higher than for E. jacksonii seedlings, consistent with findings of earlier research. For both species, initial seedling densities were significantly greater within 25 m of potential seed trees, but seedling density was otherwise unrelated to the basal area of surrounding forest. Eight years after the fire, 38% of sample quadrats (4 m2) were stocked with one or more eucalypt saplings, with saplings of E. diversicolor and E. jacksonii having a mean height of 5 m. Saplings established following the 2001 fire could add a further age class to the stand provided that this cohort persists during subsequent fires. The results of our study provide further evidence to support the view that tall open eucalypt forests in south-west Western Australia rarely experience complete stand replacement even following intense fires, and that multi-aged stands are common.

A new homothallic Phytophthora species, isolated in Western Australia (WA), is described as Phytophthora boodjera sp. nov. It produces persistent, papillate sporangia, oogonia with thick-walled oospores, and paragynous antheridia. Although morphologically similar to P. arenaria, phylogenetic analyses of the ITS, cox1, HSP90, β-tubulin and enolase gene regions revealed P. boodjera as a new species. In addition, P. boodjera has a higher optimal temperature for growth and a faster growth rate. Phytophthora boodjera has only recently been found in Western Australia and has mostly been isolated from dead and dying Eucalyptus seedlings in nurseries and from urban tree plantings, and occasionally from disturbed natural ecosystems. It is found in association with declining and dying Agonis flexuosa, Banksia media, B. grandis, Corymbia calophylla, Eucalyptus spp,. and Xanthorrhoea preissii. The status of P. alticola was also reviewed. The loss of all isolates associated with the original description except one; discrepancies in both sequence data and morphology of the remaining isolate with that presented the original description, and inconclusive holotype material places the status of this species in doubt.

Globally, drought and heat-induced forest disturbance is garnering increasing concern. Species from Mediterranean forests have resistance and resilience mechanisms to cope with drought and differences in these ecological strategies will profoundly influence vegetation composition in response to drought. Our aim was to contrast the early response of two co-occurring forest species, Eucalyptus marginata and Corymbia calophylla, in the Northern Jarrah Forest of southwestern Australia, following a sudden and severe drought event. Forest plots were monitored for health and response, three and 16 months following the drought. Eucalyptus marginata was more susceptible to partial and complete crown dieback compared to C. calophylla, three months after the drought. However, resprouting among trees exhibiting complete crown dieback was similar between species. Overall, E. marginata trees were more likely to die from the impacts of drought, assessed at 16 months. These short-term differential responses to drought may lead to compositional shifts with increases in frequency of drought events in the future.

© 2015 Elsevier B.V. We investigated the ability to accurately and non-destructively determine the germination of three native Australian tree species, Acacia cowleana Tate (Fabaceae), Banksia prionotes L.F. (Proteaceae), and Corymbia calophylla (Lindl.) K.D. Hill & L.A.S. Johnson (Myrtaceae) based on hyperspectral imaging data. While similar studies have been conducted on agricultural and horticultural seeds, we are unaware of any published studies involving reflectance-based assessments of the germination of tree seeds. Hyperspectral imaging data (110 narrow spectral bands from 423.6 nm to 878.9 nm) were acquired of individual seeds after 0, 1, 2, 5, 10, 20, 30, and 50 days of standardized rapid ageing. At each time point, seeds were subjected to hyperspectral imaging to obtain reflectance profiles from individual seeds. A standard germination test was performed, and we predicted that loss of germination was associated with a significant change in seed coat reflectance profiles. Forward linear discriminant analysis (LDA) was used to select the 10 spectral bands with the highest contribution to classifications of the three species. In all species, germination decreased from over 90% to below 20% in about 10-30 days of experimental ageing. P50 values (equal to 50% germination) for each species were 19.3 (A. cowleana), 7.0 (B. prionotes) and 22.9 (C. calophylla) days. Based on independent validation of classifications of hyperspectral imaging data, we found that germination of Acacia and Corymbia seeds could be classified with over 85% accuracy, while it was about 80% for Banksia seeds. The selected spectral bands in each LDA-based classification were located near known pigment peaks involved in photosynthesis and/or near spectral bands used in published indices to predict chlorophyll or nitrogen content in leaves. The results suggested that seed germination may be successfully classified (predicted) based on reflectance in narrow spectral bands associated with the primary metabolism function and performance of plants.

Research was conducted at Curtin University (Western Australia) to assess the seedling tolerance of three species Eucalyptus, gomphocephala DC (Myrtaceae) (common name ‘Tuart’), Eucalyptus marginata Sm. (common name ‘Jarrah’) and Corymbia calophylla (Lindl.) K.D. Hill & J. A. S. Johnson (common name ‘Marri’) to soil-induced stressor, namely water loggings (flooding). Flooding treatment was achieved by filling the tubs with water, approximately 1 cm above the soil surface and control treatment had the same method except with drainage holes. Study assessment was attained by statistical change in seedling growth, leaf allocation and leaf physiology after 70 days of seed germination. Tolerance was assessed by measuring changes in seedling growth, leaf allocation and leaf physiology after 70-80 days. C. calophylla was the most tolerant to prolonged waterlogging (80% survival, no difference in transpiration rates); E. marginata was the least tolerant (10% survival, 95% decrease in transpiration rate). E. marginata was the least tolerant to the three soil stresses. E. marginata prefers habitats that are not excessively wet on well-drained soils. C. calophylla was the most tolerant, occurring and tolerating wet, well-drained soils and thus demonstrated better tolerance to prolong waterlogging. Knowing the seedling growth and Short Communication Farifr and Aboglila; BJAST, 6(6): 644-651, 2015; Article no.BJAST.2015.119 645 physiological responses of three prominent studied eucalypts to soil-induced stresses provides us with invaluable knowledge for rehabilitating and restoring urban bush land.

Aims Anthropogenic activities disturb forests and their associated mycorrhizal fungi. The combination of climate change and habitat fragmentation are linked to increased incidence of a canker disease in a Mediterranean-type forest tree in Western Australia. As changes in communities of mycorrhizal fungi could predispose these Mediterranean-type forest trees to decline, we investigated how two aspects of mycorrhizal fungal community structure, soil propagules and resident communities on mature trees, respond to habitat fragmentation. Methods Roots were collected from a forest tree (Corymbia calophylla) across a disturbance gradient. Soil collected from the same disturbance gradient was used in a glasshouse bioassay with C. calophylla as the bioassay host (i.e., soil propagule community). After four months, we harvested the seedlings and collected roots. DNA was extracted from the field roots (resident community) and glasshouse roots (propagule community), amplified with fungal specific primers, labelled with specific barcodes and subjected to 454 pyrosequencing. Results Mycorrhizal fungal community composition overlapped substantially between the soil propagule and resident communities. However, the resident community had greater mycorrhizal fungal richness than the soil propagule community. Habitat fragmentation had a similar effect on each community structure: communities along highly fragmented areas had different community compositions than communities in a healthy forest. Conclusion With the increased mortality of C. calophylla forest trees in recent years along edge habitats, understanding the effects habitat fragmentation has on communities of mycorrhizal fungi will further elucidate host-mutualist interactions in these forest ecosystems. The changes in community composition of mycorrhizal fungal species in both propagule and resident pools can have cascading effects on future tree establishment and health by predisposing forest trees to other abiotic or biotic factors.

Extreme temperatures are causing forest dieback in a Mediterranean-type forest. Topography and cold-air pooling explain the geographic distribution of frost dieback in susceptible tree species. Alterations to the frequency and intensity of extreme temperatures, predicted with climate change, pose a threat to the health of many forests. Some Mediterranean climate regions are experiencing higher temperature variability, including more extreme low and high temperature events. Following one such low-temperature event in autumn 2012, we conducted landscape- and site-level studies to examine the impact of frost on trees and the interaction between topography, temperature, and dieback in a forest ecosystem in the Mediterranean climate region of southwest Australia. Canopy damage was widespread across the survey area and occurred in distinct patches, with sizes ranging between 4.1 and 2,518.0 ha. In affected forest, Eucalyptus marginata and Corymbia calophylla experienced nearly complete crown dieback, while E. patens and E. wandoo were undamaged. Canopy damage was found more frequently in valleys and lower to mid-slope positions, and site-level studies confirmed that crown dieback generally increased with decreasing elevation. Low temperatures were strongly correlated with elevation along damaged forest transects and cold-air pooling explained the pattern of forest damage. By regressing temperatures from damaged sites against those collected from the nearest meteorological station, projected minimum air temperatures ranged from −0.1 to −2.7 °C at valley bottom when the dieback occurred. Insufficient tissue hardening is suspected to have predisposed trees to this autumn frost. The interaction between shifting temperature regimes with climate change and frost damage is discussed. With continued increases in temperature variability, we can expect to see more temperature-driven disturbance events and associated reductions in forest health.

Worldwide, forests and woodlands have shown progressive declines in health as a result of global environmental changes in combination with local anthropogenic drivers. This study examined the incidence and progression of a canker disease of marri ( Corymbia calophylla) caused by the endemic fungal pathogen Quambalaria coyrecup at three paired forest and anthropogenically disturbed sites in the southwest of Western Australia over 13 years. At the time of plot establishment in 2001, cankers were present on trees at all six sites with 22.7% of the assessed trees cankered. By 2014, cankers had led to the death of 6.7% of the trees, and an additional 10.0% of the trees developed cankers during this time. A further 2.3% of trees died due to causes other than canker, resulting in a final figure of 65.0% of trees remaining alive and free of cankers for the duration of the survey period. Canker incidence was significantly greater on trees present at anthropogenically disturbed sites ( along roadsides and in paddocks) than forest trees ( 35.3% increasing to 50.7%, 10.0% increasing to 14.7%, respectively). Trunk diameter at breast height, tree height and crown ratings were not correlated with canker presence. This long-term study provides evidence of the increasing severity of this canker pathogen and the impact it is having on the survival of marri.