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Aims Organisms on islands are thought to escape biotic pressure and lose defensive capabilities. However, broadscale, evidence-based tests of this idea are rare. In this study, we asked: (i) whether the proportion of spinescent plant species differed between islands and mainlands and (ii) whether the proportion of spinescent species increased with increasing island area and with decreasing island distance to mainland. Methods We compiled species lists for 18 island–mainland pairs around Australia. We classified 1129 plant species as spinescent or non-spinescent using published species descriptions. Important Findings There was no significant difference between the proportion of spinescent species found on islands and on mainlands. Proportions of spinescent species were not significantly related to island area or distance to mainland. Our results suggest that spinescence is just as important to island plants as it is to mainland plants, even for plants inhabiting small or distal islands. This is unexpected, given prevailing thought and previous work on island–mainland comparisons. Our study demonstrates the importance of testing well-accepted yet untested ideas.

Rapid evolution is likely to be an important mechanism allowing native species to adapt to changed environmental conditions. Many Northern Hemisphere species have undergone substantial recent changes in phenology and morphology. However, we have little information about how native species in the Southern Hemisphere are responding to climate change. We used herbarium specimens from 21 native alpine plant species in Kosciuszko National Park, Australia, to make over 1,500 measurements of plant size, leaf thickness, leaf mass per area, leaf shape, and leaf size across the last 126 years. Only two out of 21 species (9%) showed significant changes in any of the measured traits. The number of changes we observed was not significantly different to what we would expect by chance alone, based on the number of analyses performed. This lack of change is not attributable to methodology—an earlier study using the same methods found significant changes in 70% of species introduced to southeast Australia. Australia's native alpine plants do not appear to be adapting to changed conditions, and because of the low elevation of Australia's mountains, they do not have much scope for uphill migration. Thus, our findings suggest that Australia's native alpine plants are at even greater risk in the face of future climate change than was previously understood., This study is the first test of whether alpine plants in the Southern Hemisphere have changed their morphology in response to climate change. Using herbarium specimens from 21 native alpine plant species in Kosciuszko National Park, Australia, we found that only 9% of the species showed any significant changes in plant or leaf traits over the last 126 years, standing in stark contrast to the number of changes recorded in introduced plants (up to 70%) using the same methods. A lack of morphological change combined with limited migration options suggests that native alpine plants may face a bleak future.

There is a wealth of research on the way interactions with pollinators shape flower traits. However, we have much more to learn about influences of the abiotic environment on flower colour. We combine quantitative flower colour data for 339 species from a broad spatial range covering tropical, temperate, arid, montane and coastal environments from 9.25o S to 43.75o S with 11 environmental variables to test hypotheses about how macro-ecological patterns in flower colouration relate to biotic and abiotic conditions. Both biotic community and abiotic conditions are important in explaining variation of flower colour traits on a broad scale. The diversity of pollinating insects and the plant community have the highest predictive power for flower colouration, followed by mean annual precipitation and solar radiation. On average, flower colours are more chromatic where there are fewer pollinators, solar radiation is high, precipitation and net primary production is low, and growing seasons are short, providing support for the hypothesis that higher chromatic contrast of flower colours may be related to stressful conditions. To fully understand the ecology and evolution of flower colour, we should incorporate the broad selective context that plants experience into research, rather than focussing primarily on effects of plant-pollinator interactions.

This study examined the assisted natural restoration of native vegetation in an Australian floodplain wetland where flows were reinstated and the river was reconnected to the floodplain, following cessation of agricultural cultivation. Extant vegetation was surveyed three times during an inundation event at plots with different land‐use histories. Restoration rate was more influenced by past land use than long‐term inundation frequency and success decreased with antecedent land‐use intensity. Prolonged land‐use history (>3 years cultivation) restricted restoration success. Sites with longer cultivation histories tended to have fewer aquatic species, more terrestrial species and exotic species. For example, amphibious responders with floating leaves were found only in reference plots and less frequently in farmed treatment plots. In this scenario, increased persistence of exotics and dryland species suggested alternative trajectories. Fields with a short land‐use history (1–3 years of clearing and cultivation) resembled undisturbed floodplain communities, consistent with a ‘field of dreams’ hypothesis. Although river–floodplain reconnections can restore wetlands, legacy effects of past land use may limit the pace and outcomes of restoration.

Large urban trees have many benefits. However, falling branches pose a serious hazard to both people and infrastructure. In several tree species, aerial roots grow down from branches to the ground. These roots are capable of thickening to support the branches, lessening the risk of tree failure. Unfortunately, in urban environments most aerial roots die before reaching the ground. Here, we report a new method for encouraging aerial roots to reach the ground, developed by the second-year botany class at UNSW Sydney. Our class tested three experimental treatments on aerial roots of Ficus rubiginosa Desf. ex Vent. (Port Jackson Fig)—PVC pipes filled with sphagnum moss, PVC pipes filled with potting mix, and PVC pipes filled with sphagnum moss and topped with funnels to catch extra rainwater. All three treatments significantly improved aerial root growth, with 26 of the 30 (87%) treatment roots reaching the ground after one year compared to 0 of the 10 control roots. Our method was successful for roots up to 3 m above the ground, suggesting the potential growth rate of aerial roots is substantial when conditions are favourable. Our novel approach is an attractive and cost-effective alternative to slings and other artificial supports. This project is an example of using undergraduate practical classes to teach science while simultaneously addressing important real-world problems.

Trace and major element composition of selected plant species and parts may be used to map geochemical dispersion from mineral deposits and contaminated areas. This study examines the application of field-portable X-ray fluorescence spectrometry (fpXRF) in obtaining real-time biogeochemical data. In situ analysis of parts of black and silver wattle (Acacia mearnsii De Wild. and Acacia dealbata Link) was conducted to map the extent of contamination surrounding the former Woodlawn base metal mine. High levels of ore-related elements were detected in the bark of these species in a zone extending up to 1 km down-drainage from the tailing ponds. Major elements are more elevated in bark on the side of the trees facing the tailings ponds and correlations between trace and major elements indicate dust contamination. The penetration distance for X-rays is dependent on the energy of the secondary X-rays measured, with the maximum depth of penetration in bark and leaf material30 mm. There was a close correlation for most elements between the fpXRF and laboratory-based XRF analysis but with element-dependent attenuation by the organic matrix. Providing there is consistency in sampling and analytical methodology, in situ fpXRF analysis of vegetation is an effective method in both contamination surveys and biogeochemical mineral exploration for a range of trace and major elements.

Relocating a natural history collection is a daunting prospect. Underpinning successful relocation is getting the fundamentals right. From the moment the seed of an idea for a new facility is planted, a raft of detailed planning and preparation issues emerge. Meticulous planning and management is essential, from initial design through to the last specimen being housed in its new location. Herbaria are complex organisms each with a core collection of specimen sheets and associated infrastructure to house them; ancillary collections such as ‘spirit’ and ‘DNA’, a library, databasing, mounting, materials, imaging, loans and exchange, facilities for environmental control, biosecurity, space for staff, volunteers, research students, and class or public access and outreach. All these elements require careful consideration for relocation regardless of the size of the collection. Timelines for relocations from initial decisions to commencement of the move vary widely. Early involvement of core herbarium staff is critical to managing risks to the integrity of the collection during a move. Success of the operation can be gauged immediately after the move and again, much later, based on feedback on the operation of the facility and whether planned expansion will meet future needs. All these considerations are important and essentially the same, irrespective of distance of relocation or size of the collection. We will discuss the fundamental issues of herbarium relocation based on two recent case studies.The Western Australian Herbarium moved from its 1970s home to a modern, purpose-built, best practice facility incorporating innovative design features in 2011 with c. 800,000 specimens. The John T. Waterhouse Herbarium at UNSW Sydney (The University of New South Wales) moved c. 66,000 specimens in October 2017 from within a 1962 departmental building, to a modern, purpose-built facility, incorporating significant improvements, as part of a much larger relocation of its School. We will provide a guide to assist future relocations, both imminent (such as the N.C.W. Beadle Herbarium at the University of New England (>100,000 specmens), and the National Herbarium of New South Wales, >1,400,000 specimens) and for those yet to be considered. This will be a presentation on behalf of the Managers of Australasian Herbarium Collections (MAHC), a network of herbarium Collection Managers in Australia and New Zealand.

Aim The idea that species are generally more colourful at tropical latitudes has held great appeal among biologists since the days of exploration by early naturalists. However, advances in colour quantification and analysis only now allow an objective test of this idea. We provide the first quantitative analysis of the latitudinal gradient in colour on a broad scale using data from both animals and plants, encompassing both human-visible and ultraviolet colours. Location Australia. Methods We collected spectral reflectance data from 570 species or subspecies of birds, adult forms of 424 species or subspecies of butterflies and the flowers of 339 species of plants, from latitudes ranging from tropical forests and savannas at 9.25° S, to temperate forests and heathlands at 43.75° S. Colour patch saturation, maximum contrast between patches, colour diversity and hue disparity between patches were calculated for all species. Latitudinal gradients in colour were analysed using both regression analyses and comparisons of categorically temperate and tropical regions. We also provide phylogenetically independent contrast analyses. Results The analyses which compared the colour traits of communities and the phylogenetically independent contrasts both show that species in the tropics are not more colourful than those at higher latitudes. Rather, the cross-species analyses indicate that species further away from the equator possess a greater diversity of colours, and their colours are more contrasting and more saturated than those seen in tropical species. These results remain consistent regardless of whether the mean or the maximum of coloration indices are considered. Main conclusions We demonstrate that birds, butterflies and flowers display similar gradients of colourfulness across latitudes, indicating strong ecological and evolutionary cohesion. However, our data do not support the idea that tropical latitudes contain the most colourful species or house the more colourful biological communities.

Questions Understanding how trees affect their understorey plants and soils is crucial to understand savanna ecosystems. Most studies focus on the differences between canopy and open microsites, but how do different positions within large tree canopies influence soils and plants? Are these potential differences likely to change depending on environmental conditions (i.e. annual rainfall and grazing)? Location One hundred sites across a rainfall gradient (220–1400 mm) in NSW, Australia. Methods We measured the cover, richness and community composition of understorey plants and 12 soil attributes related to infiltration, erodibility and fertility across three positions within the canopy of large eucalypts (trunk, mid-canopy and edge) and in open areas. We also estimated the percentage similarity in plant communities across microsites, and the percentage species within the landscape occurring solely in one of the four microsites assayed. We tested the interactions between the effect of environmental conditions (rainfall and grazing) and canopy position on all these soil and vegetation attributes. Results Soil attributes explained ~50% of the effect of trees on understorey plants, and soil attributes improved with proximity to the trunk and increasing rainfall. The effect of canopy position × rainfall interactions depended on the response variable considered. These interactions did not affect soil attributes, the percentage of facilitation-obligate species or species richness, and weakly affected plant composition. However, we found a strong reduction in similarity among plant communities within edge and mid-canopy compared with open sites towards drier environments, and canopy position × rainfall interactions also significantly affected plant cover. We attribute these weak interactions between canopy position and environmental conditions to richness or the frequency of facilitation to the high turnover of facilitated species across microsites and across different environmental conditions. Conclusions Our study can be used to better understand community dynamics in ecosystems with scattered trees by showing the differential effects of trees on their understorey. Our results also contribute to the body of research on the relationships between plant–plant interactions and the environment by illustrating the importance of gradient length and the number of different microsites considered.

Question: Are plant traits more closely correlated with mean annual temperature, orwithmean annual precipitation? Location: Global. Methods: We quantified the strength of the relationships between temperature and precipitation and 21 plant traits from 447,961 species-site combinations worldwide. We used meta-analysis to provide an overall answer to our question. Results: Mean annual temperature was significantly more strongly correlated with plant traits than was mean annual precipitation. Conclusions: Our study provides support for some of the assumptions of classical vegetation theory, and points to many interesting directions for future research. The relatively low R

The outcome of plant-plant interactions depends on environmental (e.g. grazing, climatic conditions) and species-specific attributes (e.g. life strategy and dispersal mode of the species involved). However, the joint effects of such factors on pairwise plant-plant interactions, and how they modulate the role of these interactions at the community level, have not been addressed before. We assessed how these species-specific (life strategy and dispersal) and environmental (grazing and rainfall) factors affected the co-occurrence of 681 plant species pairs on open woodlands in south-eastern Australia. Species-specific attributes affected the co-occurrence of most species pairs, with higher co-occurrence levels dominating for drought-intolerant species. The dispersal mechanism only affected drought-tolerant beneficiaries, with more positive co-occurrences for vertebrate-dispersed species. Conversely, the percentage of facilitated species at the community scale declined under higher rainfall availabilities. A significant grazing × rainfall interaction on the percentage of facilitated species suggests that grazing-mediated protection was important under low to moderate, but not high, rainfall availabilities. This study improves our ability to predict changes in plant-plant interactions along environmental gradients, and their effect on community species richness, by highlighting that: 1) species-specific factors were more important than environmental conditions as drivers of a large amount (~30%) of the pairwise co-occurrences evaluated; 2) grazing and rainfall interaction drive the co-occurrence among different species in the studied communities, and 3) the effect of nurse plants on plant species richness will depend on the relative dominance of particular dispersal mechanisms or life strategies prone to be facilitated.

Summary 1. We provide a brief overview of progress in our understanding of introduced plant species. 2. Three main conclusions emerge from our review: (i) Many lines of research, including the search for traits that make species good invaders, or that make ecosystems susceptible to invasion, are yielding idiosyncratic results. To move forward, we advocate a more synthetic approach that incorporates a range of different types of information about the introduced species and the communities and habitats they are invading. (ii) Given the growing evidence for the adaptive capacity of both introduced species and recipient communities, we need to consider the implications of the long-term presence of introduced species in our ecosystems. (iii) Several foundational ideas in invasion biology have become widely accepted without appropriate testing, or despite equivocal evidence from empirical tests. One such idea is the suggestion that disturbance facilitates invasion. 3. We use data from 200 sites around the world to provide a broad test of the hypothesis that invasions are better predicted by a change in disturbance regime than by disturbance per se .N either disturbance nor change in disturbance regime explained more than 7% of the variation in the % of cover or species richness contributed by introduced species. However, change in disturbance regime was a significantly better predictor than was disturbance per se, explaining approximately twice as much variation as did disturbance.

Managers of Australasian Herbarium Collections (MAHC) is a sub-committee of the Council of Heads of Australasian Herbaria (CHAH) and provides advice and recommendations pertaining to the management of herbarium collections. It was formed in 2009 based initially on Australian herbaria, and later incorporated New Zealand herbaria. MAHC currently has 18 member institutions representing both government funded, and university based herbaria, and includes both the largest (National Herbarium of Victoria - MEL) and smallest collections (Macquarie University - MQU) in the region. The group meets in person annually, and holds regular conference phone calls throughout the year. MAHC has proved itself to be a very cohesive committee, despite time, sizing, staffing, and funding differences. It prides itself in being inclusive, cooperative, collegiate, collaborative and supportive. It has a strong mentor approach toward early career collections managers or those new to collections management. The group has a healthy forward planning outlook, developing, promoting and implementing collections management policy, recommendations, guidelines and standards. This cohesion has resulted in a toolkit of resources that are freely available and strives for a unified world class best practice herbarium curation. Some of these universally agreed tools include templates, biosecurity documents, disaster mitigation and preparation for Nagoya Protocol implementation for Australia and New Zealand. MAHC supports new international initiatives and manages the day to day running of programmes such as the Global Plants Initiative project imaging all vascular type specimens housed in Australasia. MAHC collaborates with CHAH and the data sub-committee, HISCOM (Herbarium Information Systems Committee), for continued improvements in sharing digital data and specimens via the Australasian Virtual Herbarium (AVH https://avh.chah.org.au/) and Atlas of Living Australia (ALA https://www.ala.org.au/) services. This talk will use examples to highlight the effectiveness and success of a unified group in: developing standard practice in curation, incorporating improved curation procedures, and its ability to be agile, responding to incidents at an international level.

Summary 1. Plant height is a central part of plant ecological strategy. It is strongly correlated with life span, seed mass and time to maturity, and is a major determinant of a species’ ability to compete for light. Plant height is also related to critical ecosystem variables such as animal diversity and carbon storage capacity. However, remarkably little is known about global patterns in plant height. Here, we use maximum height data for 7084 plant Species · Site combinations to provide the first global, cross-species quantification of the latitudinal gradient in plant height. 2. The mean maximum height of species growing within 15� of the equator (7.8 m) was 29 times greater than the height of species between 60� and 75� N (27 cm), and 31 times greater than the height of species between 45� and 60� S (25 cm). There was no evidence that the latitudinal gradient in plant height was different in the northern hemisphere than in the southern hemisphere (P = 0.29). A 2.4-fold drop in plant height at the edge of the tropics (P = 0.006) supports the idea that there might be a switch in plant strategy between temperate and tropical zones. 3. We investigated 22 environmental variables to determine which factors underlie the latitudinal gradient in plant height. We found that species with a wide range of height strategies were present in cold, dry, low productivity systems, but there was a noticeable lack of very short species in wetter, warmer, more productive sites. Variables that capture information about growing conditions during the harsh times of the year were relatively poor predictors of height. The best model for global patterns in plant height included only one term: precipitation in the wettest month (R 2 =0 .256). 4. Synthesis. We found a remarkably steep relationship between latitude and height, indicating a major difference in plant strategy between high and low latitude systems. We also provide new, surprising information about the correlations between plant height and environmental variables.

Sand dunes on the Newnes Plateau (1000 m a.s.l.), west of Sydney, were active during the Last Glacial Maximum. The scattered sand dunes are forested under the modern humid, temperate climate regime. Dune types range from parabolic to transverse lee dunes and sand sheets or patches. All point to the presence of conditions marginal for aeolian activity, made possible through wind acceleration on windward slopes, ready sand supply from the weathered sandstone of the plateau and sparse vegetation cover. Modern climate envelopes of sand dune activity in Australia predict that unrealistically drier conditions are necessary to allow wind transport at this site. Only additional impediments to plant growth, such as lower temperature and lower atmospheric carbon dioxide concentrations, appear to allow the necessary conditions for dune formation. These observations and conclusions extend our understanding of the extremes of the LGM climate in humid eastern Australia, confirming that the widespread treeless vegetation was also sparse, even in areas that today have annual rainfall above 1000 mm.

Early flowering plants are thought to have been woody species restricted to warm habitats. This lineage has since radiated into almost every climate, with manifold growth forms. As angiosperms spread and climate changed, they evolved mechanisms to cope with episodic freezing. To explore the evolution of traits underpinning the ability to persist in freezing conditions, we assembled a large species-level database of growth habit (woody or herbaceous; 49,064 species), as well as leaf phenology (evergreen or deciduous), diameter of hydraulic conduits (that is, xylem vessels and tracheids) and climate occupancies (exposure to freezing). To model the evolution of species' traits and climate occupancies, we combined these data with an unparalleled dated molecular phylogeny (32,223 species) for land plants. Here we show that woody clades successfully moved into freezing-prone environments by either possessing transport networks of small safe conduits and/or shutting down hydraulic function by dropping leaves during freezing. Herbaceous species largely avoided freezing periods by senescing cheaply constructed aboveground tissue. Growth habit has long been considered labile, but we find that growth habit was less labile than climate occupancy. Additionally, freezing environments were largely filled by lineages that had already become herbs or, when remaining woody, already had small conduits (that is, the trait evolved before the climate occupancy). By contrast, most deciduous woody lineages had an evolutionary shift to seasonally shedding their leaves only after exposure to freezing (that is, the climate occupancy evolved before the trait). For angiosperms to inhabit novel cold environments they had to gain new structural and functional trait solutions; our results suggest that many of these solutions were probably acquired before their foray into the cold. © 2014 Macmillan Publishers Limited. All rights reserved.

Nature 506, 89–92 (2014); doi:10.1038/nature12872 corrigendum Nature 514, 394 (2014); doi:10.1038/nature13842 Three readers pointed out that in this Letter we applied the threshold of 0.044 (the size at which freezing-induced embolisms are believed to become frequent at modest tensions) to the area of the conduit (in mm2) rather than the diameter (in mm).