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Exposure to rainfall inhibits the reflectiveness of glossy buttercup petals
Get PDFRanunculus flower petals possess a multilayered structure that enhances the reflectance of ultraviolet (UV) and visible light. This study investigated how water interferes with the structural colouration in Ranunculus graniticola flowers, using spectrophotometry to compare the reflectance of petals exposed to dry versus wet weather conditions. Petals recently exposed to rainfall showed lower reflectance in the visible spectra and almost no UV reflectance; upon returning to dry conditions UV reflectance increased at a linear rate. During rainfall, water invades the air layer between the upper epidermis and the starch layer of the mesophyll, which restricts the scattering effect of the starch cells. The glossy surface of the petals was unchanged by exposure to water, indicating that the gloss is not the cause of the remarkably high UV reflectance seen in Ranunculus flowers. The significance of these results were discussed in relation to two prominent theories about the adaptive purpose of Ranunculus structural colouration
Effect of drought on plant physiology, disease susceptibility and insect herbivory in rainforest saplings
Get PDFTwo rainforest canopy tree species were sampled as saplings in June of 2022 in a cross-sectional study to compare the effect of drought on physiological performance, insect herbivory and leaf disease damage. Throughfall infrastructure was utilised to simulate drought in field conditions. A strong effect of drought was found across all physiological measures, with drought being correlated with lower leaf chlorophyll content, stomatal conductance, and photosystem 2 efficiency. Plant health was assessed at the leaf-level using a 0-5 visual scale. No significant effect of drought on insect herbivory of disease damage was found, except for in Argyrodendron peralatum. Correlation of physiological performance and individual health assessments revealed several trends in susceptibility. Chlorophyll content was found to be more steeply correlated to insect damage severity in drought treatments than in control treatments, the effect of stomatal water conductance was investigated, and reduction in efficiency of photosystem 2 was correlated to higher severity of affliction. Mechanisms behind trends in susceptibility were investigated but the inference power of this study was limited by the cross-sectional nature. A longitudinal study tracking the progression of plant health metrics, physiological performance, and development was suggested for future research in conjunction with studies that analyse drought impact on invertebrate communities.  
Since 1945, in Asia, have Alliances Formed and Functioned as Expected by Alliance Theory?
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Preference and avoidance behaviour of Chrysomelid beetles using olfactory sensing of potential host-tree competitors
Get PDFChrysomelid beetles are a family of phytophagous insects which feed on nutritious young Eucalyptus leaves. Though they have been known to cause extensive damage to Eucalyptus crops, they are considered a charismatic native insect in Australia. Comparatively, the Steelblue sawfly (Perga affinis), more commonly known as “spitfires” are known to not only affect, but strip entire trees of their leaves, particularly in Eucalyptus crops. In Kosciuzsko National Park, NSW, we investigated the olfactory preferences of Chrysomelid beetles when presented with a variety of odours. We aimed to identify the attractance and avoidance behaviours of these beetles to their potential competitior, the Steelblue sawfly, using a Y-maze olfactometer. Results revealed a complex relationship between these herbivores and their host plant, whilst illuminating possible hijacking of P. affinis pheromones by Chrysomelid beetles in order to maximise their nutrition from foraging, both as adults and larvae. An increase in P. affinis population in the area could cause the Chrysomelid beetles to be outcompeted. By understanding the preference and avoidance behaviours of these beetles, we can better manage and maintain their populations into the futur
The effects of drought on the leaf-litter invertebrates of an Australian Wet Tropics ecosystem: the Daintree Rainforest: Effects of drought on tropical leaf-litter invertebrates
No full textClimate change is impacting ecosystems worldwide, and tropical rainforests, in particular, are extremely vulnerable. Tropical rainforests are predicted to experience drought events with increasing frequency, duration and severity. Understanding how drought will impact these ecosystems is critical to management strategies. In particular, understanding how drought will impact tropical leaf-litter invertebrates will provide insight into broader impacts across the entire ecosystem. We investigated the impacts of drought on leaf-litter invertebrate abundance and diversity in the Daintree Rainforest of Far North Queensland, Australia. Additionally, we investigated the ways in which litter depth, soil moisture and substrate type impact leaf-litter invertebrate abundance. We found that neither number of functional groups nor number of orders was different in drought-treated sites compared to control sites, but that invertebrate abundance was significantly lower in drought-treated sites. We found that neither soil moisture nor litter depth had any significant effect on leaf-litter invertebrate abundance or diversity. Substrate type did not affect the number of functional groups or orders present, but we found significantly higher leaf-litter invertebrate abundance in sites with rock substrate, compared to soil substrates
Exploring Processes of Radicalisation in Jihadist Terrorist Organisations : Investigating different factors that enable the cross-border radicalisation and recruitment of ‘home-grown’ terrorists.
Get PDFPhotosynthetic capacity and water use efficiency of Argyrodendron peralatum leaves across a vertical gradient
Get PDFA simple model of rainforest resource allocation is the Big Leaf Theory model. Rainforest ecosystems distribute resources to the canopy in order to maximise the benefits of increased irradiance exposure. Argyrodendron peralatum is an Australian tree species, endemic to Far North Queensland. Through analysis of photosynthetic capacity and stomatal capacity, which also allows analysis of water use efficiency, across understory, mid canopy, and top canopy levels, it was shown that A. peralatum follows the Big Leaf Theory model; performing these functions at higher rates at the top canopy level
Drivers of floristic composition in Bukit Timah Nature Reserve: an investigation of leaf functional traits
Get PDFForest fragmentation and associated edge effects can lead to considerable ecosystem degradation resulting in high mortality and loss of biodiversity. Bukit Timah Nature Reserve is a forest fragment that has been closely monitored for nearly 20 years. Though fragmentation is typically associated with negative consequences, Bukit Timah showed unexpected resilience to fragmentation effects. Interestingly, alterations in community structure were observed, though significant changes in stem density and basal area did not occur. The aim of this study was to explore the drivers of said compositional change, through examining four species of tropical rainforest trees. Two of these species are currently increasing in abundance (Shorea curtisii and Streblus elongatus) and two are decreasing in abundance (Gynotroches axillaris and Santiria apiculata). The study examined leaf mass per area, chlorophyll content, leaf thickness, and stomatal density. The results showed significant differences between species in trait values for all four functional traits, but no overarching trends to explain alteration in species composition were found. The results indicate that the four functional traits assessed are not critical in shaping community composition. Potential other drivers are explored, such as correlation with water transport systems. This is timely and important research in the face of dwindling primary forest in South-East Asia, and represents a global shift in priorities towards protecting ecological biodiversity
The cultural conditions of Cold War Australia: Conventions of and challenges to the ‘Australian Way of Life’ from 1947 to 1972
Get PDFThis essay explores the role of the Cold War in Australian cultural life from 1947 to 1972 and the extent to which the encroachment of polarising politics on the domestic sphere transformed ideals of the supposed ‘Australian Way of Life’. Through analysis of the social expressions of ‘Old’ and ‘New’ Australians during the Cold War period, I chart the trends and transitions in Australian cultural identity and the shift from traditional fixations on national isolation and ethnic homogeneity toward a more diverse population and global outlook. While historiographical analysis has traditionally categorised the Cold War era by decades of dissimilarity—with the 1950s considered a time of anxious conformity and the 1960s associated with progressive social change—considerable cultural debate concerning the character and stability of the ‘Australian Way of Life’ endured throughout the period. Questioning the widespread assumption of Australian cultural life as a derivative backwater, this essay argues that demographic, social, and intellectual transitions generated by the Cold War forced the growing populace, and both sides of the ideological spectrum, to confront their place in the world and imagine the nation anew into the second half of the twentieth century