Subcontinental heat wave triggers terrestrial and marine, multi-taxa responses

Heat waves have profoundly impacted biota globally over the past decade, especially where their ecological impacts are rapid, diverse, and broad-scale. Although usually considered in isolation for either terrestrial or marine ecosystems, heat waves can straddle ecosystems of both types at subcontinental scales, potentially impacting larger areas and taxonomic breadth than previously envisioned. Using climatic and multi-species demographic data collected in Western Australia, we show that a massive heat wave event straddling terrestrial and maritime ecosystems triggered abrupt, synchronous, and multi-trophic ecological disruptions, including mortality, demographic shifts and altered species distributions. Tree die-off and coral bleaching occurred concurrently in response to the heat wave, and were accompanied by terrestrial plant mortality, seagrass and kelp loss, population crash of an endangered terrestrial bird species, plummeting breeding success in marine penguins, and outbreaks of terrestrial wood-boring insects. These multiple taxa and trophic-level impacts spanned \u3e300,000 km2—comparable to the size of California—encompassing one terrestrial Global Biodiversity Hotspot and two marine World Heritage Areas. The subcontinental multi-taxa context documented here reveals that terrestrial and marine biotic responses to heat waves do not occur in isolation, implying that the extent of ecological vulnerability to projected increases in heat waves is underestimated

A threatened ecological community: Research advances and priorities for Banksia woodlands

The rapid expansion of urban areas worldwide is leading to native habitat loss and ecosystem fragmentation and degradation. Although the study of urbanisation\u27s impact on biodiversity is gaining increasing interest globally, there is still a disconnect between research recommendations and urbanisation strategies. Expansion of the Perth metropolitan area on the Swan Coastal Plain in south-western Australia, one of the world\u27s thirty-six biodiversity hotspots, continues to affect the Banksia Woodlands (BWs) ecosystem, a federally listed Threatened Ecological Community (TEC). Here, we utilise the framework of a 1989 review of the state of knowledge of BWs ecology and conservation to examine scientific advances made in understanding the composition, processes and functions of BWs and BWs\u27 species over the last 30 years. We highlight key advances in our understanding of the ecological function and role of mechanisms in BWs that are critical to the management of this ecosystem. The most encouraging change since 1989 is the integration of research between historically disparate ecological disciplines. We outline remaining ecological knowledge gaps and identify key research priorities to improve conservation efforts for this TEC. We promote a holistic consideration of BWs with our review providing a comprehensive document that researchers, planners and managers may reference. To effectively conserve ecosystems threatened by urban expansion, a range of stakeholders must be involved in the development and implementation of best practices to conserve and maintain both biodiversity and human wellbeing

Linking hydraulic conductivity and photosynthesis to water-source partitioning in trees versus seedlings

The relationships between hydraulic and photosynthetic properties in plants have been widely studied, but much less is known about how these properties are linked to water-source partitioning, the spatial and temporal separation of water sources in ecosystems. Plant water-source partitioning is often influenced by the proximity of groundwater from the natural surface. We studied the water acquisition strategy and hydraulic and photosynthetic properties of Tuart (Eucalyptus gomphocephala D.C.), a large coastal tree species that occupies seasonally dry habitats underlain by superficial aquifers. Our goal was to quantify water-source partitioning as the proportion of xylem water derived from the vadose and saturated zones with respect to stage of development and proximity of groundwater. We then sought to associate the proportional contribution of a given water source with xylem hydraulic and photosynthetic properties, thus conferring a linkage. Seedlings were more inclined to use surface soil water when rainfall recharge of the upper profile occurred, suggesting that they maintained or rapidly developed a proportionally high amount of functional roots in the upper, seasonally dry, soil profile. This strategy was associated with a lower xylem-area-specific hydraulic conductivity (KS), leaf-area-specific hydraulic conductivity (KL) and maximum photon yield of photosystem II (FV/FM). In contrast, trees acquired water from a variety of sources in different seasons and had a higher KS, KL and FV/FM. Despite the higher KS and KL in trees, the midday hydrodynamic water potential gradient from soil to leaves, ΔΨ, was similar. We conclude that there was a linkage between hydraulic and photosynthetic properties with the partitioning of water sources and that this adaptation to long-term hydrological regimes accommodated the different hydraulic characteristics and hydrological environments of trees versus seedlings

Subcontinental heat wave triggers terrestrial and marine, multi-taxa responses

Heat waves have profoundly impacted biota globally over the past decade, especially where their ecological impacts are rapid, diverse, and broad-scale. Although usually considered in isolation for either terrestrial or marine ecosystems, heat waves can straddle ecosystems of both types at subcontinental scales, potentially impacting larger areas and taxonomic breadth than previously envisioned. Using climatic and multi-species demographic data collected in Western Australia, we show that a massive heat wave event straddling terrestrial and maritime ecosystems triggered abrupt, synchronous, and multi-trophic ecological disruptions, including mortality, demographic shifts and altered species distributions. Tree die-off and coral bleaching occurred concurrently in response to the heat wave, and were accompanied by terrestrial plant mortality, seagrass and kelp loss, population crash of an endangered terrestrial bird species, plummeting breeding success in marine penguins, and outbreaks of terrestrial wood-boring insects. These multiple taxa and trophic-level impacts spanned >300,000 km(2)-comparable to the size of California-encompassing one terrestrial Global Biodiversity Hotspot and two marine World Heritage Areas. The subcontinental multi-taxa context documented here reveals that terrestrial and marine biotic responses to heat waves do not occur in isolation, implying that the extent of ecological vulnerability to projected increases in heat waves is underestimated.Western Australian State Centre of Excellence for Climate Change, Woodland and Forest Health; Sir Walter Murdoch Distinguished Collaborator Award from Murdoch University; U.S. National Science Foundation [EF-1340649, EF-1550756]; Consortium for Arizona-Mexico Arid Environments; Arizona Agriculture Experiment Station; Australian Research Council Discovery Early Career Researcher Grant [DE170100102]Open access journal.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]