National Ecosystem Assessment System for Australia (NEASA): Phase 1

A national set of conceptual models for Australia's landscapes

Australia needs a way to map, monitor and predict trajectories of its natural and modified ecosystems at regional and national scales, in a consistent and repeatable way. Through its National Ecosystem Assessment System for Australia (Phase 1), TERN is developing new infrastructure and tools towards this goal. It will synthesise empirical data and expert knowledge of ecosystem change, building conceptual models to facilitate integration of real-world data into ecosystem assessments, predictions and scenarios. Such a capability will inform local to regional land use planning decisions, systems of national ecosystem accounts, state of the environment reporting, indicators for global reporting to the Convention on Biological Diversity, nature positive initiatives, and climate adaptation decisions, among other uses.

Previous work established the Australian Ecosystem Models Framework, a framework for systematically capturing ecological knowledge about the dynamics of Australian ecosystems in pre- and post-industrialisation contexts (Richards et al. 2020). The framework recognises 14 umbrella ecosystem types that reflect the Major Vegetation Groups of Australia's National Vegetation Information System. Within each of these umbrella groups, two types of conceptual models can be accommodated: (1) archetype ecosystem models and (2) state-and-transition models.

Model type 01

Archetype ecosystem models

The framework aims to capture best available knowledge of pre-industrialisation ecosystem dynamics in the form of "archetype" conceptual ecosystem models. These involve simple box-and-arrow diagrams, where boxes represent the different forms or "expressions" expected for an ecosystem type (defined by biotic and abiotic attributes), and arrows represent drivers of change between expressions. Drivers in archetype models include only those likely to have been present prior to European colonisation and industrialisation (i.e. endogenous disturbances), including drivers based on Indigenous land management regimes. For example, intense wildfire may shift an obligate-seeder woodland from a mature stand to a juvenile expression comprising dense seedling recruitment (Fig. 1).

Archetype models are published as they are completed. For example, Prober et al. (2023a,b) and Roxburgh et al. (2023) describe models for eucalypt woodlands, mallee and eucalypt forests, respectively.

Figure 1 — Archetype ecosystem model diagram

Fig. 1 — Example archetype model showing state transitions in an obligate-seeder eucalypt woodland.

Model type 02

Ecosystem state and transition models

State and transition models in the Australian Ecosystem Models Framework aim to capture the key post-industrialisation dynamics of Australian ecosystem types (Fig. 2). "States" represent modified forms of the reference ecosystems that have resulted from post-industrialisation (i.e. exogenous) disturbances. Consistency across ecosystem types will be facilitated by development of generalised sets of modified ecosystem states and drivers.

These will be used as building blocks for state and transition conceptual model templates relevant to each archetype. Templates can be used to add further detail or parameterised for modelling ecosystem futures at local, regional or national scales. Changes in expressions reflecting endogenous drivers can be captured within each state.

Figure 2 — State and transition model diagram

Fig. 2 — Generalised state and transition model template showing post-industrialisation dynamics.

Booklets

Aggregate Ecosystem Groups

The framework organises Australia's ecosystems into 14 Aggregate Ecosystem Groups (AEGs). Each AEG booklet describes a set of archetype ecosystem models. Select a group to view the archetype models it contains and, where available, download the booklet.

Callitris forests and woodlands 2 archetype models Available

Archetype models in this booklet