A new classification approach: improving the regional ecosystem classification system in Queensland, Australia

Eda Addicott designed a quantitative approach for identifying the plant communities in Queensland. She found that plant communities identified using the new approach were more recognisable and more useful for land management planning. The Queensland Herbarium is using the new approach to identify plant communities as a state-wide standard

Three decades of monitoring the woody layer of tropical eucalypt woodlands of northern Queensland

Thirty years of vegetation monitoring data in the eastern savannas of Australia provides some insights into the temporal dynamics of woodlands at these sites, and supplements long-term savanna studies in the Northern Territory. Across four sites in four ecosystems, there was an increase in native shrub species abundance consequent with a decrease of canopy species abundance in the low tree and canopy layers. Even though some individuals from a variety of species persisted through at least six fires, with three developing to be low subcanopy trees, there were no individuals that survived to become canopy trees. The loss of canopy trees with no replacement and recent increase in the non-native shrub Stylosanthes scabra may indicate an ecosystem under stress leading to long-term changes in structure and species composition at these site

Aligning quantitative vegetation classification and landscape scale mapping: updating the classification approach of the Regional Ecosystem classification system used in Queensland.

Vegetation classification systems form a base for conservation management and the ecological exploration of the patterns and drivers of species’ distributions. A standardised system crossing administrative and geographical boundaries is widely recognised as most useful for broad-scale management. The Queensland Government, recognising this, uses the Regional Ecosystem (RE) classification system and accompanying mapping as a state-wide standardised vegetation classification system. This system informs legislation and policy at local, state and national levels, underpinning decisions that have wide-ranging implications for biodiversity and people’s livelihoods. It therefore needs to be robust from a scientific and legal perspective. The current approach in the RE system for identifying vegetation communities relies on expert-based class definition procedures. This is in contrast to best practice, which is based on quantitative procedures. This paper discusses the RE system in a global context and outlines the updated approach that incorporates quantitative class definition procedures, synthesises the research behind the updated approach and discusses its implications and implementation

Poplar box woodlands of Eastern Australia: an assessment of a threatened ecological community within the IVC framework

Aims: Ecosystems nationally at risk in Australia are listed under the Environmental Protection and Biodiversity Act (EPBC Act), and many cross State jurisdictional boundaries. The determination of these ecosystems across the State boundaries are based on expert knowledge. The International Vegetation Classification has the potential to be useful as a cross-jurisdictional hierarchy which also gives global perspective to ecosystems. Study Area: All bioregions that include Eucalyptus populnea as a dominant or major component of woodlands across the species known distribution. Methods: We use plot-based data (455 plots) from two states (Queensland and New South Wales) in eastern Australia and quantitative classification methods to assess the definition and description for the Poplar Box Woodland ecosystem type (hereafter "ecological community" or "community") that is listed as endangered under the EPBC Act. Analyses were conducted using kR-CLUSTER methods to generate alliances. Within these alliances, analyses were undertaken to define associations using agglomerative hierarchical clustering and similarity profile testing (SIMPROF). We then explore how assigning this community into the IVC hierarchy may provide a mechanism for linking Australian communities, defined at the association and alliance levels, to international communities at risk. Results: We define three alliances and 23 associations based on the results of floristic analysis. Using the standard rule-set of the IVC system, we found that the IVC hierarchy was a useful instrument in correlating ecological communities across jurisdictional boundaries where different classification systems are used. It is potentially important in giving a broader understanding of communities that may be at risk continentally and globally. Conclusions: We conclude that the IVC hierarchy can incorporate Australian communities at the association level into useful units at higher levels, and provides a useful classification tool for Australian ecosystems

Australian advances in vegetation classification and the need for a national, science-based approach

This editorial introduces the Australian Journal of Botany special issue ‘Vegetation science for decision-making’. Vegetation science and classification are crucial to understanding Australian landscapes. From the mulga shrublands of the arid interior to the monsoon rain forests of northern Australia, we have culturally and scientifically built upon the delineation of vegetation into recognisable and repeatable patterns. As remote sensing and database capacities increase, this improved capability to measure vegetation and share data also prompts collaboration and synthesis of complex, specialised datasets. Although the task faces significant challenges, the growing body of literature demonstrates a strong discipline. In Australia, purpose-driven products describe vegetation at broad scales (e.g. the National Vegetation Information System, the Terrestrial Ecosystem Research Network). At fine scales however (i.e. that of the vegetation community), no uniform framework or agreed protocols exist. Climate and landform dictate vegetation patterns at broad scales, but microtopography, microclimate and biotic processes act as filters at finer scales. This is the scale where climate-change impacts are most likely to be detected and effected; this is the scale at which a deeper understanding of evolutionary ecology will be achieved, and it is the scale at which species need to be protected. A common language and system for understanding Australian communities and impetus for collecting data at this scale is needed. In the face of ongoing climate and development pressures and an increasingly complex set of tools to manage these threats (e.g. offset policies, cumulative impact assessments), a nationally collaborative approach is needed. It is our hope that this special issue will help to achieve this

Australian vegetation classification and the International Vegetation Classification framework: an overview with case studies

Recent advances in conceptual frameworks in vegetation classifications, such as the EcoVeg approach that underpins the International Vegetation Classification (IVC) developed by NatureServe staff and colleagues, offer opportunities to enhance national classification initiatives. National level initiatives provide an important stepping-stone between international units and subnational units. Australia has a long history of developing various vegetation typologies at local to regional scales, but ecologists recognise the need for an Australia-wide, plot-based vegetation classification system that incorporates the principles of the EcoVeg approach, and thereby helps build an international classification system. Using two case studies, we provide a comparison of various structures and criteria for relevant Australian classifications in the context of the IVC, and exemplify how Australian classifications of forest, shrublands, grasslands, and deserts could potentially link into the IVC hierarchy to illustrate the capacity of the IVC to summarise the full range of Australian vegetation at a broad formation (biome) scale. We then discuss how the IVC might inform future work towards an Australian vegetation classification system and, vice versa, the implications of an Australian vegetation classification for IVC development

A plot-based analysis of the vegetation of the Northern Territory, Australia: a first assessment within the International Vegetation Classification framework

Aims: To develop an interim classification of the vegetation of the Northern Territory at the International Vegetation Classification (IVC) division (level 4) and macrogroup (level 5) levels. These types are produced to assist in the development of an integrated nationwide plot and floristically based classification of Australia allowing integration within a global perspective. Study Area: The Northern Territory of Australia covers an area of 1.42 million square kilometres, almost 20% of Australia’s land mass. It comprises three distinct climatic zones including tropical, subtropical and arid vegetation types. Methods: We used collated vegetation data held by two organisations: the Northern Territory Government, Department of Environment, Parks and Water Security and the Terrestrial Ecosystem Research Network (a total of 45,710 plots used). We applied semi-supervised quantitative classification methods to define vegetation types at the IVC division and macrogroup levels. Analyses used kR-CLUSTER methods on presence/absence data. Macrogroups were characterised by taxa with the highest frequency of occurrence across plots. Additional analyses were conducted (cluster) to elucidate interrelationships between macrogroups and to assist in the assessment of division level typology. Results: We propose 21 macrogroups and place these within higher thematic levels of the IVC. Conclusions: We found that the IVC hierarchy and associated standard procedures and protocols provide a useful classification tool for Australian ecosystems. The divisions and macrogroups provide a valid framework for subsequent analysis of Northern Territory vegetation types at the detailed levels of the IVC. A consistent typology for the Northern Territory (and hopefully in future, for all of Australia) has numerous benefits, in that they can be used for various applications using a well-structured, systematic and authoritative description and classification that is placed in a continental and global context, readily enabling the one system to be used in studies from the local to global level. Taxonomic reference: Northern Territory Herbarium (2022). Abbreviations: DVT = Definitive Vegetation Type; IVC = International Vegetation Classification; nMDS = non-metric multidimensional scaling; NT = Northern Territory; NTVSD = Northern Territory Vegetation Site Database; NVIS = National Vegetation Information System; WA = Western Australia

Supervised versus un‐supervised classification: a quantitative comparison of plant communities in savanna vegetation

Question: What are the differences between plant communities recognised using supervised versus un‐supervised methods? Location: Northeastern Australia. Methods: Two classifications of savanna plant communities were formed independently with two different approaches: supervised and un‐supervised (using agglomerative hierarchical clustering). Each approach used the same vegetation datasets and, importantly, classification criteria. The communities occur on two different landscapes, with differing environmental gradients, covering an area of 53,500 km2. We compared the internal characteristics of plant communities between approaches and landscapes using four evaluation criteria: identifiability, distinctiveness, similarity of internal heterogeneity and predictability of species foliage cover. Additionally, we compared the central floristic concepts and compositional boundaries of communities identified by each approach. Results: Supervised and un‐supervised approaches recognised similar floristic community concepts. Compositional boundaries between communities were similar on the landscape with steeper environmental gradients but significantly different on the landscape with gradual environmental gradients. However, communities distinguished using supervised methods were significantly less distinct and identifiable, worse at predicting species foliage cover and significantly more variable in species composition than those identified using un‐supervised methods. Conclusions: Using supervised rather than un‐supervised approaches to distinguish plant communities can result in less recognisable communities, possibly reducing their usefulness for land management planning. Importantly, we found a large disparity between the two approaches in delineating compositional boundaries between communities on landscapes with gradual environmental gradients. This is particularly relevant to communities in biomes such as the savanna which comprises 20% of the Earth's landmass. Ecologists can be more confident using a supervised approach on landscapes with steep environmental gradients but should target landscapes with gradual environmental gradients for un‐supervised classification

The intertidal plant communities in north-eastern Australia, their carbon stores and vulnerability to extreme climate events

During the strong El Nino event of 2015-2016 large-scale dieback of mangrove forests was observed in the Gulf of Carpentaria region of northern Australia. These and other intertidal communities are also extensive along the 7,400 km coastline of north-eastern Australia. Determination of their floristic composition, potential carbon (C) store and sequestration capacity, and vulnerability to climate extremes is required for their effective conservation management and was the aim of this study. Standardized, state-wide quantitative classification methods identified five mangrove forest and three saltmarsh communities covering 2,604 km(2)along this coastline. Estuarine and oceanic mangrove forests were mapped separately. Carbon storage and sequestration capacity of the intertidal communities and their vulnerability to strong El Nino events were estimated using published data and GIS analyses. An estimated potential 126.2 (+/- 27.3 SEM) Tg C and 8.3 (+/- 0.4 SD) Tg C were stored in the mangrove forests and saltmarshes, respectively. Comparatively, the rainforests of the region stored an estimated equivalent amount of C but covered three times the area, and the most widespread woodlands (Eucalyptus tetrodonta) of the region stored an estimated 1.5 times the C but covered 16 times the area. The C stored in the intertidal communities was estimated as equivalent to 493.47 Tg of CO(2,)valued at AU$6.8 billion on the Australian carbon market in December 2018. Annual C sequestration potential was 0.18-0.34 Tg C/year, valued between AU$8.9 and $17 million. Approximately 360 ha of mangrove forest was estimated as lost because of dieback during the 2015-16 El Nino event. Three types of mangrove forest were identified as potentially vulnerable to dieback from El Nino-driven climate events. This study highlights the national and global significance of these intertidal systems and our findings need to be incorporated in future conservation and development planning of northern Australia