Vegetation of Australian Riverine Landscapes: biology, ecology and management

Vegetation communities in Australia's riverine landscapes are ecologically, economically and culturally significant. They are also among the most threatened ecosystems on the continent and have been dramatically altered as a result of human activities and climate change. Vegetation of Australian Riverine Landscapes brings together, for the first time, the results of the substantial amount of research that has been conducted over the last few decades into the biology, ecology and management of these important plant communities in Australia. The book is divided into four sections. The first section provides context with respect to the spatial and temporal dimensions of riverine landscapes in Australia. The second section examines key groups of riverine plants, while the third section provides an overview of riverine vegetation in five major regions of Australia, including patterns, significant threats and management. The final section explores critical issues associated with the conservation and management of riverine plants and vegetation, including water management, salinity, fire and restoration. Vegetation of Australian Riverine Landscapes highlights the incredible diversity and dynamic nature of riverine vegetation across Australia, and will be an excellent reference for researchers, academics and environmental consultants

Planning for climate change northern monsoon cluster: decision making and planning for natural resource management

Natural resource managers are tasked with a range of challenging and sometimes competing management objectives but often have limited resources with which to achieve them. Natural resource management (NRM) objectives typically include conserving biodiversity, maintaining healthy ecosystems, achieving water quality targets and restoring degraded habitats. A key challenge is to identify where, when and how to implement effective activities to achieve these objectives with the least cost and impact on stakeholders. This project provided and tested an appropriate decision support framework for cross-realm planning and supporting synthesis of NRM plans to assist natural resource management groups in northern Australia successfully tackle this challenge

Riverine trees and shrubs

[Extract] From coastal estuaries to the vast floodplains of the arid interior, woody plants can be found in a wide range of riverine habitats throughout Australia. Although often absent from areas that experience frequent and prolonged flooding, as well as many saline wetlands of inland Australia (Specht 1990), trees and shrubs form a considerable diversity of riverine vegetation communities across the continent including closed and open forests, woodlands and shrub lands, in addition to many areas dominated by herbaceous vegetation that also support scattered trees and shrubs. Despite this structural diversity, woody riparian vegetation in Australia is often locally dominated by one to a few species, many of which are also widespread across the continent (e.g. Eucalyptus camaldulensis, river red gum) (Capon and Dowe 2007). Among these are a handful of rheophytes (e.g. Casuarina cunninghamiana, river she-oak) adapted to growing in swiftly flowing waters as well as trees and shrubs characteristic of marginal flood-plain habitats that may be inundated less frequently than once a decade (e.g. E. largiflorens, black box), but nevertheless rely on inundation for their survival. Wherever woody plants occur in riverine landscapes, however, and in whatever form, they play an integral role in shaping the environments of which they are a part – physically, ecologically and culturally

Vegetation of Australia's desert river landscapes

[Extract] Australia is renowned for being the driest inhabited continent on Earth and ‘a land of droughts and flooding rains’ (Dorothea Mackellar). Over one-third of Australia’s land area can be considered ‘arid’ and a further third ‘semi-arid’ (Martin 2006). Importantly, these areas are characterised not just by extended periods of low rainfall but also extremely patchy and unpredictable rainfall that sometimes produces enormous floods, driving some of the most expansive and dynamic riverine landscapes in Australia and the world

Climate change and the future of Australian riverine vegetation

[Extract] Freshwater and riparian ecosystems are likely to be highly vulnerable to the effects of the current phase of rapid, anthropogenic climate change because of their high levels of exposure and sensitivity to changes in climatic stimuli. Furthermore, the adaptive capacity of these ecosystems has been limited due to human activities (Capon et al. 2013; Capon and Bunn 2015). Riverine vegetation is exposed to all the direct influences of rising CO 2and the climatic changes driven by this described for terrestrial vegetation, including elevated temperatures, altered precipitation and evapotranspiration pat-terns. Additionally, climate change has many indirect effects on riverine vegetation as a result of changes in soil moisture, hydrology and, in coastal situations, sea level rise and storm surges. Arguably, no other vegetation type is subject to the same levels of exposure and yet relatively little is known about how plants in Australian riverine habitats may respond

Nurse plant effects of a dominant shrub (Duma florulenta) on understorey vegetation in a large, semiarid wetland in relation to flood frequency and drying

Questions: Do nurse plant interactions significantly influence understorey vegetation diversity in a large, semi-arid, shrub-dominated wetland? How do the modes and net effects of nurse plant interactions vary spatially along a flood frequency gradient, and temporally in response to drying?\ud \ud Location: Narran Lakes Ramsar site, New South Wales, Australia.\ud \ud Methods: Microhabitat characteristics, understorey vegetation and germinable soil seed banks were investigated in shrub and open habitats across a flood frequency gradient in a large, semi-arid wetland dominated by open shrubland under productive conditions following floodwater recession and again following 6 mo of drought. Split-plot ANOVA and multivariate analyses were used to determine the effects of shrubs on microhabitat character, understorey vegetation cover, species diversity, richness and composition and germinable soil seed banks.\ud \ud Results: Microhabitat characteristics, including canopy cover, litter cover and soil character, all differed between shrub and open habitats, especially in the most frequently flooded sites. Under productive conditions following flooding, lignum shrubs suppressed understorey vegetation cover but increased species richness at the site scale across the flood frequency gradient and, in the most frequently flooded sites, supported higher species density at a microhabitat scale. Under dry conditions, lignum shrubs had a positive effect on understorey vegetation cover, species richness and species density across the flood frequency gradient, but particularly in frequently flooded sites. A significant difference in soil seed bank composition between shrub and open habitats was only observed in frequently flooded sites.\ud \ud Conclusions: Nurse plant interactions appear to play an important role in determining understorey vegetation diversity in the lignum shrubland of the Narran Lakes wetland system. The modes and net effects of these nurse plant interactions vary in space and time in relation to flood history and drying. Positive interactions, probably involving microhabitat amelioration, appear to be particularly important to plant diversity and abundance under dry conditions. Under more favourable wetter conditions, lignum shrubs also contribute to understorey vegetation diversity by facilitating the establishment of different species than those dominating open habitats. Our findings have implications for the management of perennial shrubs and hydrological regimes in such wetlands

Climate change and the future of Australian riverine vegetation

[Extract] Freshwater and riparian ecosystems are likely to be highly vulnerable to the effects of the current phase of rapid, anthropogenic climate change because of their high levels of exposure and sensitivity to changes in climatic stimuli. Furthermore, the adaptive capacity of these ecosystems has been limited due to human activities (Capon et al. 2013; Capon and Bunn 2015). Riverine vegetation is exposed to all the direct influences of rising CO 2and the climatic changes driven by this described for terrestrial vegetation, including elevated temperatures, altered precipitation and evapotranspiration pat-terns. Additionally, climate change has many indirect effects on riverine vegetation as a result of changes in soil moisture, hydrology and, in coastal situations, sea level rise and storm surges. Arguably, no other vegetation type is subject to the same levels of exposure and yet relatively little is known about how plants in Australian riverine habitats may respond

Sink or swim? potential for high faunal\ud turnover in Australian rivers under\ud climate change

Aim: Climate change threatens biodiversity in all ecosystems, and major shifts in species distributions are expected. Freshwater ecosystems are considered particularly vulnerable due to the ectothermic physiology of most freshwater species and their limited habitat extent and capacity to track climate trends. In this study, we examined what broad patterns in freshwater riverine species turnover might be expected under climate change across continental Australia and what are the implications of these patterns for aquatic species and the low aquatic biodiversity of some bioregions?\ud \ud Location: Continental Australia.\ud \ud Methods: We built statistical relationships between bioclimatic environments and the occurrence of species of four freshwater taxa (freshwater fish, crayfish, turtles and frogs) and examined trends in projected species turnover for a ‘business as usual’ climate scenario. We used Maxent to model species distributions and present the median projection across 18 global climate models. A recently derived national stream network was used to generate estimates of mean annual river flow and to produce realistic species distributions and migration options by restricting dispersal and migration opportunities usually available to riverine fauna.\ud \ud Results: High species turnover was driven overwhelmingly by potential local extinctions particularly for stream frogs and crayfish where their current biodiversity is largely confined to higher elevation headwater streams. We predicted high turnover for inland regions of Australia, which are arid and generally support fewer freshwater species.\ud \ud Main conclusions: Our analysis indicates that under the most severe emissions pathway, projected climate change is likely to cause substantial changes to the composition of faunal assemblages in Australian rivers well before the end of this century. While freshwater systems globally are subject to immediate and pressing threats from anthropogenic land and water use, management interventions addressing these pressures need to be considered within the context of climate change