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With climate zones moving poleward, it is interesting to know how rapidly species are gained and lost along temperature gradients. For the Australian native vascular flora, observed climate envelopes for species distributions have here been calculated from data for occurrence at geographical locations. For each degree temperature increase along a continental temperature gradient, numbers of species crossing their cold boundary and hence added to the flora, and crossing their warm boundary and hence lost to the flora, were counted. These counts of gains and losses were expressed as percentages of the flora recorded as present at that temperature. We report results for the flora at > 700 mm rainfall pa along the Australian east coast, where higher rainfall is continuously distributed throughout the latitudinal range. Per °C mean annual temperature increase, 20 ± 11% (mean ± SD) of species were gained, and 14 ± 4% were lost, across the range 9–23°C. Many further questions arise. For example, which other continental floras might show faster or slower rates of species gain and loss along temperature gradients? Similarly, might species with particular traits show faster rates of turnover: for example, species with local dispersal such as those with diaspore morphologies adapted for ants, compared to those adapted for bird dispersal? [ABSTRACT FROM AUTHOR]

When leaves exceed their thermal threshold during heatwaves, irreversible damage to the leaf can accumulate. However, few studies have explored short-term acclimation of leaves to heatwaves that could help plants to prevent heat damage with increasing heatwave intensity. Here, we studied the heat tolerance of PSII (PHT) in response to a heatwave in Acacia species from across a strong environmental gradient in Australia. We compared PHT metrics derived from temperature-dependent chlorophyll fluorescence response curves (T–F 0) before and during a 4-day 38°C heatwave in a controlled glasshouse experiment. We found that the 15 Acacia species displayed surprisingly large and consistent PHT acclimation responses with a mean tolerance increase of 12°C (range, 7.7–19.1°C). Despite species originating from diverse climatic regions, neither maximum temperature of the warmest month nor mean annual precipitation at origin were clear predictors of PHT. To our knowledge, these are some of the largest measured acclimation responses of PHT from a controlled heatwave experiment. This remarkable capacity could partially explain why this genus has become more diverse and common as the Australian continent became more arid and suggests that the presence of Acacia in Australian ecosystems will remain ubiquitous with climate change. The tolerance of plants to extreme temperatures is important for the future of ecosystems. Recent studies of rapid acclimation in plants typically find low acclimation capacity (+1–3°C) in response to heatwaves. By contrast, in 15 Acacia species, we find consistent, unprecedented acclimation capacity to heatwaves (+12°C) irrespective of climatic origin. [ABSTRACT FROM AUTHOR]

Aim: Our ability to understand how species may respond to changing climate conditions is hampered by a lack of high‐quality data on the adaptive capacity of species. Plant functional traits are linked to many aspects of species life history and adaptation to environment, with different combinations of trait values reflecting alternate strategies for adapting to varied conditions. If the realized climate limits of species can be partially explained by plant functional trait combinations, then a new approach of using trait combinations to predict the expected climate limits of species trait combinations may offer considerable benefits. Location: Australia. Time period: Current and future. Methods: Using trait data for leaf size, seed mass and plant height for 6,747 Australian native species from 27 plant families, we model the expected climate limits of trait combinations and use future climate scenarios to estimate climate change impacts based on plant functional trait strategies. Results: Functional trait combinations were a significant predictor of species climate niche metrics with potentially meaningful relationships with two rainfall variables (R2 =.36 &.45) and three temperature variables (R2 =.21,.28,.30). Using this method, the proportion of species exposed to conditions across their range that are beyond the expected climate limits of their trait strategies will increase under climate change. Main conclusions: Our new approach, called trait strategy vulnerability, includes three new metrics. For example, the climate change vulnerability (CCV) metric identified a small but important proportion of species (4.3%) that will on average be exposed to conditions beyond their expected limits for summer temperature in the future. These potentially vulnerable species could be high priority targets for deeper assessment of adaptive capacity at the genomic or physiological level. Our methods can be applied to any suite of co‐occurring plants globally. [ABSTRACT FROM AUTHOR]