• Energy Research

Potential interactions between climate change and exotic plant invasions may affect areas of high conservation value, such as land set aside for the protection of endangered species or ecological communities. We investigated this issue in eastern Australia using species distribution models for five exotic vines under climate regimes for 2020 and 2050. We examined how projected changes in the distribution of climatically suitable habitat may coincide with the remaining remnants of an endangered ecological community—littoral rainforests—in this region. The number of known infestations of each weed in tropical, subtropical and temperate areas was used to assess the likelihood of further expansion into areas projected to provide suitable habitat under future conditions. Littoral rainforest reserves were consistently predicted to provide bioclimatically suitable habitat for the five vines examined under both current and future climate scenarios. We explore the consequences and potential strategies for managing exotic plant invasions in these protected areas in the coming decades.

Predicting the influence of climate change on the potential distribution of naturalised alien plant species is an important and challenging task. While prioritisation of management actions for alien plants under current climatic conditions has been widely adopted, very few systems explicitly incorporate the potential of future changes in climate conditions to influence the distribution of alien plant species. Here, we develop an Australia-wide screening tool to assess the potential of naturalised alien plants to establish and spread under both current and future climatic conditions. The screening tool developed uses five spatially explicit criteria to establish the likelihood of alien plant population establishment and expansion under baseline climate conditions and future climates for the decades 2035 and 2065. Alien plants are then given a threat rating according to current and future threat to enable natural resource managers to focus on those species that pose the largest potential threat now and in the future. To demonstrate the screening tool, we present results for a representative sample of approximately 10% (n = 292) of Australia's known, naturalised alien plant species. Overall, most alien plant species showed decreases in area of habitat suitability under future conditions compared to current conditions and therefore the threat rating of most alien plant species declined between current and future conditions. Use of the screening tool is intended to assist natural resource managers in assessing the threat of alien plant establishment and spread under current and future conditions and thus prioritise detailed weed risk assessments for those species that pose the greatest threat. The screening tool is associated with a searchable database for all 292 alien plant species across a range of spatial scales, available through an interactive web-based portal at http://weedfutures.net/.

Globally, local governments are increasing investment in urban greening projects. However, there is little consideration of whether the species being planted will be resilient to climate change. We assessed the distribution of climatically suitable habitat, now and in the future, for 176 tree species native to Australia, commonly planted across Australia's Significant Urban Areas (SUAs) and currently grown by commercial nurseries. Species' occurrence records were obtained from inventories and herbaria, globally and across Australia, and combined with baseline climate data (WorldClim, 1960-1990) and six climate scenarios for 2030 and 2070 using climatic suitability models (CSMs). CSMs for each species were calibrated and projected onto baseline and future scenarios. We calculated changes in the size of climatically suitable habitat for each species across each SUA, and identified urban areas that are likely to have suitable climate for either fewer or more of our study species under future climate. By 2070, climatically suitable habitat in SUAs is predicted to decline for 73% of species assessed. For 18% of these species, climatically suitable area is predicted to be more than halved, relative to their baseline extent. Generally, for urban areas in cooler regions, climatically suitable habitat is predicted to increase. By contrast, for urban areas in warmer regions, a greater proportion of tree species may lose climatically suitable habitat. Our results highlight changing patterns of urban climatic space for commonly planted species, suggesting that local governments and the horticultural industry should take a proactive approach to identify new climate-ready species for urban plantings.

Abstract Approximately eight billion people are living on Earth today with more than half (55%, ∼4.2 billion) living in cities—a proportion predicted to increase to 70% (∼6.6. billion) by 2050. As the human population grows, urban residents will face increasingly extreme temperatures under future climate change, which will affect human well-being, health, and mortality. However, nature-based solutions offer promising strategies to mitigate these impacts. Here, we analyst future projections of the maximum temperature of the warmest month, as a proxy for extreme heat exposure across 5646 cities in 218 countries. We show that by mid-century, this climate metric is projected to increase by an average of +1.7 °C (± 0.5 °C), with the largest increases (∼4 °C) projected to occur in mid-to-high latitude cities of Europe, North America, and Australia. We highlight the urgent need to adopt nature-based solutions to mitigate projected increases in urban heat and contribute to net-zero CO2 emissions goals.

In a meta-analysis, we use an unprecedented dataset, representing 556 unique locations worldwide, distributed across 44 countries and six continents to show for the first time that lianas (woody vines) thrive relatively better than trees when forests are disturbed, temperature increase, precipitation decrease, and particularly in tropical lowlands. We demonstrate that liana dominance can persist for decades post-disturbance and hinder the recovery of disturbed forests, especially when climate favours lianas. With implications for the global carbon sink, our findings suggest that degraded tropical forests with environmental conditions favouring lianas should be the highest priority to consider for restoration management.

AbstractSpecies that cannot adapt or keep pace with a changing climate are likely to need human intervention to shift to more suitable climates. While hundreds of articles mention using translocation as a climate‐change adaptation tool, in practice, assisted migration as a conservation action remains rare, especially for animals. This is likely due to concern over introducing species to places where they may become invasive. However, there are other barriers to consider, such as time‐frame mismatch, sociopolitical, knowledge and uncertainty barriers to conservationists adopting assisted migration as a go‐to strategy. We recommend the following to advance assisted migration as a conservation tool: attempt assisted migrations at small scales, translocate species with little invasion risk, adopt robust monitoring protocols that trigger an active response, and promote political and public support.

1AbstractMean annual precipitation (MAP) plays an undisputed role in determining the spatial distribution of the vegetative ecosystems on Earth. Nevertheless, the relationship between MAP and plant functional traits remains unclear. Here, we test the relationship between eight key functional traits and MAP. Our analysis reveals a strong, coordinated response of several plant traits including leaf mass per area, leaf nitrogen, the leaf carbon isotope ratio and plant height from resource-conservative to resource-acquisitive values as MAP increased. These results establish an important role for MAP in driving trait selection across space and, therefore, a need for these effects to be included in future theoretical frameworks.

AbstractVegetation is composed of many individual species whose climatic tolerances can be integrated into spatial analyses of climate change risk. Here, we quantify climate change risk to vegetation at a continental scale by calculating the safety margins for warming and drying (i.e., tolerance to projected change in temperature and precipitation respectively) across plants sharing 100 km × 100 km grid cells (locations). These safety margins measure how much warmer, or drier, a location could become before its ‘typical’ species exceeds its observed climatic limit. We also analyse the potential adaptive capacity of vegetation to temperature and precipitation change (i.e., likelihood of in situ persistence) using median precipitation and temperature breadth across all species in each location. 47% of vegetation across Australia is potentially at risk from increases in mean annual temperature (MAT) by 2070, with tropical regions most vulnerable. Vegetation at high risk from climate change often also exhibited low adaptive capacity. By contrast, 2% of the continent is at risk from reductions in annual precipitation by 2070. Risk from precipitation change was isolated to the southwest of Western Australia where both the safety margin for drier conditions in the typical species is low, and substantial reductions in MAP are projected.