2026 Cumberland Plain Research Symposium

Allow time to come up the lifts, register your name, and take your seat before the Welcome.

Welcome to Country

Uncle Chris Tobin, Darug Elder, Artist & Educator, Western Sydney University

Opening Remarks

Associate Professor Paul Rymer, Lead Investigator Cumberland Plain Research Program, Hawkesbury Institute for the Environment, Western Sydney University

NSW Department of Planning, Housing and Infrastructure

INVITED: Cultural Burn - Teresa James Reserve

Joshua Staines, First Nations Program Manager, Penrith City Council | Master's Candidate, Hawkesbury Institute for the Environment, Western Sydney University

INVITED: Patterns in Management Actions and Associated Costs for the NSW Biodiversity Offset Sites

Dr Steph Hernandez, Senior Project Officer (Decision Science) & Research Scientist, Strategic Science (Nature) | Science and Insights Division, Department of Climate Change, Energy, the Environment and Water

The Biodiversity Offset Scheme in New South Wales (NSW), Australia, provides a framework for mitigating the impact of development on biodiversity through the establishment and management of dedicated offset sites. The choice of management actions at offset sites is a consequence of ecological, economic and social factors and results from the negotiation between landholders, accredited ecological consultants and government officers. We evaluated the relative importance of ecological characteristics and financial incentives in shaping management actions across 57 offset sites covering 28,300 ha. We hypothesised that the combination of management actions chosen for an area, as articulated in a site’s management plan, would vary depending on the initial ecological condition, vegetation type, evidence of missing habitat features, and likely threatening processes. However, our findings indicate a tendency to implement a standardised set of actions irrespective of the ecological context. We discuss these general patterns and their exceptions. For example, at most sites, weed management, notably spot-spraying herbaceous species, dominated the total management costs, loosely related to site-specific conditions. Similarly, where environmental plantings were undertaken, the majority were tree and shrub plantings, with few sites targeting ground cover species, and fewer still accounting for any site preparation or follow-up actions needed to maximise the likelihood for success. We discuss the implications of our findings for the potential biodiversity benefits that may arise at offset sites.

Spatio-temporal patterns of enrolment in private land conservation agreements across nested scales

Emmanuel Ugwu, PhD Candidate, Hawkesbury Institute for the Environment, Western Sydney University

The land use decisions of private landholders play a critical role in shaping the geographies of ecosystem persistence, nature exposure, and public health, particularly in contexts like New South Wales (NSW) where a considerable portion of land is private owned or managed. Government-administered private land conservation agreements provide a legally binding structure for supporting landholders’ commitment to accountably protect biodiversity on their properties. However, distrust of government institutions and considerations of opportunity costs often inhibit uptake of the conservation agreements. We analysed active enrolments in private land conservation agreements from 1960 to 2025 in NSW to understand (1) the spatial and temporal patterns of landholders’ uptake of private land conservation agreements in NSW, Western Sydney and the Cumberland Plain Conservation Plan (CPCP) Strategic Conservation Area and (2) opportunities for improving landholder participation and ecological outcomes. Findings show that conservation agreements with the lowest barriers to entry and exit, Wildlife Refuge Agreements, attracted the highest number of enrolments and the largest enrolled parcels statewide and in Western Sydney. Wildlife Refuge Agreements were also associated with the most populous clusters of connected parcels, having the greatest number of >=4 adjacent parcels. About 96.5% of enrolled parcels in NSW are protected permanently, while 3.5% are term agreements. The median duration of the term agreements was 20 years while the minimum duration was 15 years. We suggest that improving flexibility attributes of conservation agreements and strategic landholder outreach might help to expand enrolment decisions in priority areas, improving prospects of long-term stewardship, landscape connectivity, and access to nature.

Posters:

• Dylan Bristol, Western Sydney University

• Sophia Bruna, Western Sydney University

• Eric Coracero, Western Sydney University

• Zahra Emlaei, Western Sydney University

• Simba Gombedza, Western Sydney University

• Awapa Jirabanjongjit, Western Sydney University

• Dr Isabel Kilian Salas, Western Sydney University

• Briony Lewis, University of New England

• Paola Pisetta Raupp, Western Sydney University

• Krish Singh, Western Sydney University

• Vidula Varadarajan, Western Sydney University

• Venkatesh Vimulapati, Western Sydney University

INVITED: Insights into conservation of native vegetation in fragmented landscapes from long term studies

Professor David Keith, Laureate Professor of Botany, Centre for Ecosystem Science, University of NSW

The remaining extent of Cumberland Plain Woodland declined from 9% to 6% of its pre-European extent over the past 25 years, marking accelerated diminution and degradation that began 235 years ago. Options for conservation of its remaining biodiversity are rapidly evaporating under enormous pressures on multiple fronts, yet there have never been more resources and incentives available to implement conservation measures to halt and reverse the declines. What should be done to support well-informed and effective action? While rates and localities of decline in extent can be tracked with precision by remote sensing, the patterns and causes of degradation are less understood. What are the overall trends in ecosystem integrity under dual influences of conservation management and ongoing degradation pressures? Are the smallest and most isolated remaining fragments already committed to ecosystem collapse or can they still make effective contributions to the viability of the remaining biota? What other factors are influencing the viability of remnant biota? How feasible is it to reverse declines in extent by reconstructing Cumberland Plain Woodland in areas where it has previously been eliminated? How can key methodological challenges in assessing and monitoring the trajectories of remaining vegetation be overcome? In this presentation, I aim to provide some answers to these questions from long-term studies on vegetation of Cumberland Plain Woodland. The results reveal some counter-intuitive insights and complex dependencies that suggest more nuanced approaches to planning, regulation, management and monitoring are essential to arrest and reverse declines in regional biodiversity.

Cumberland Plain Restoration Program

Vera O’Donovan, Project Officer-Threatened Species, NSW National Parks and Wildlife Service

The Cumberland Plain Restoration Program (CPRP) has recently completed its eighth year, supported by funding from the Environmental Trust. The program implemented an integrated suite of restoration activities aimed at improving the ecological condition and resilience of Cumberland Plain ecosystems, including fire management through cultural and ecological burns, vegetation management through native plant thinning and targeted weed control, and habitat restoration through the installation of artificial hollows and coarse woody debris. This presentation will examine vegetation responses recorded in long-term monitoring plots following fire and associated management treatments. Comparisons will be made among three treatment regimes: (a) Bursaria spinosa trittering and eucalypt sapling thinning followed by fire and targeted weed control; (b) fire followed by weed control; and (c) untreated control sites. Findings provide insights into the effectiveness of combined restoration approaches for enhancing vegetation structure and composition. Habitat restoration outcomes will also be presented. Three types of artificial hollows were installed to support key fauna, including hollows designed for the Eastern Free-tailed Bat, Little Lorikeet, and glider species, with the latter intended to increase prey availability for the Masked Owl. In addition, pre- and post-installation surveys of the Cumberland Plain Land Snail were undertaken to assess the benefits of coarse woody debris as habitat. These surveys provide valuable and unique insights into practical strategies for increasing habitat suitability and supporting the conservation of this threatened species.

Mat Misdale, Senior Project Officer - Conservation Planning and Implementation, NSW Department of Planning, Housing and Infrastructure

Characterisation of 8 CPW Restorations 10-years Post Seeding

Dr Paul Gibson-Roy, Restoration Ecologist, NSW Department of Climate Change, Energy, the Environment and Water

In 2016 Greening Australia (with support from various government and other partners) undertook a series of restorations of CPW across Western Sydney. The programs intent was to apply a range of techniques developed in the 2000s in Victoria which had proved successful in restoring native ground-layer species to highly modified, weed or exotic dominated sites. These techniques included the application of cultivated seed production to supply seed resources, direct seeding of multi-species seed mixes using specialised seeding machinery, and soil manipulation to treat soil weed seed/bud banks and elevated nutrients. All the restoration sites in Western Sydney were dominated by exotic weeds prior to restoration and situated on various land tenures - including public and private. In late 2015 and early 2026 detailed assessments were made at 8 sites to ascertain if these techniques and the subsequent (varied) management of sites had resulted in a shift from the initial state of weed dominance to one of native dominated vegetation. This presentation reports on these findings.

Spatially Explicit Revegetation to Enhance Biodiversity Outcomes in Cumberland Plain Woodland

Dr Rajendra Shilpakar, Senior Land Services Officer, Greater Sydney Local Land Services

Spatial heterogeneity is increasingly recognised as a key driver of ecological resilience and biodiversity outcomes in revegetation programs. This study demonstrates how Greater Sydney Local Land Services is restoring structural and floristic complexity in a Cumberland Plain Woodland (CPW) revegetation project at Orchard Hills using a spatially explicit design approach.

The project area comprises 40 zones requiring revegetation following historic clearing. Each zone was classified into one of three Plant Community Types (PCTs): Cumberland Red Gum Riverflat Forest (PCT 4025), Cumberland Shale Plains Woodland (PCT 3320), and Cumberland Shale Hills Woodland (PCT 3319). Surrounding remnant vegetation was assessed to inform zone-specific species mixes, ensuring alignment with local ecological conditions.

Species-specific spacing requirements were then determined to support the development of appropriate woodland structure, including spreading canopies that facilitate hollow formation and coarse woody debris recruitment. Minimum spacing parameters were derived from measurements of ‘reference’ trees (trees with preferred habitat attributes) identified through forest dynamic monitoring (FDM) research at the site.

To replicate natural spatial heterogeneity, planting locations were generated using the random point function in ArcGIS Pro, constrained by minimum spacing requirements. These spatially explicit planting points were published as an ArcGIS Online feature service and consumed into the Field Maps application. A mobile differential GPS (DGPS) system integrated with Field Maps enabled contractors to precisely locate and mark each planting position in the field at sub-meter accuracy.

Drone video footage and rapid field assessments confirms strong alignment between implemented plantings and the designed spatial patterns. A long-term monitoring framework has also been established to evaluate biodiversity responses to this approach.

This project demonstrates that spatially explicit, heterogeneous revegetation is a practical and scalable method for improving biodiversity outcomes in ecological restoration, particularly in highly modified landscapes such as the Cumberland Plain.

A first look at how climate sensitivity is distributed across plant diversity in the Cumberland Plains

Dr Hannah Carle, Postdoctoral Researcher, Hawkesbury Institute for the Environment, Western Sydney University

Purpose: Climate change is intensifying chronic and acute climate stress on plants, and restoration and management actions need to manage this risk. A major challenge is to anticipate how these climate risks are distributed: which groups of plants most need us to step in and help? While climate manipulation experiments can characterise individual species sensitivities, applying these findings to diverse landscapes is often crippled by reliance on a small suite of species that do not capture biodiversity.

Methodology: We selected a diverse array of 32 species from the Cumberland Plain IBRA subregion, Australia, spanning growth forms, diverse leaf characteristics, and divergent climate-origins, habitats, and frequency in the landscape. We then used a climate manipulation experiment (warming-by-water-by-heatwave) to evaluate how climate sensitivity is distributed across floral diversity. Plants were grown with chronic water limitation (well-watered versus water-limited) and chronic warming (+5°C, two months), then exposed to an acute 5-day heatwave (35±4°C) to test for plant responses to single and combined stressors. Plants were monitored weekly for canopy desiccation and harvested for biomass and leaf structural traits.

Key findings: Chronic water limitation generally increased canopy desiccation and reduced biomass growth, while the effect of chronic warming was more mixed. The impacts of warming plus water limitation were often additive or multiplicative. Climate sensitivity was distributed unevenly across floral diversity, with herbaceous species more sensitive than woody species, and further differences between tuberous versus seeder forbs, and C3 and C4 graminoids. Within and across groups, climate responses were highly species specific but were broadly predicted by differences in warm- and dry-edge limits of species climate origin, as well as allocation traits (leaf mass area and root mass fraction).

Synthesis: Our approach provides a framework for incorporating species diversity in climate manipulation experiments to better support predictions of ecosystem responses to the growing pressures associated with climate change.

Reserve rating tool guides restoration and biodiversity connectivity targets across NSWs largest Council

Dr Alison Hewitt, Senior Biodiversity Officer (ecologist), Blacktown Council

Blacktown Council have developed a novel reserve rating tool to guide resource investment, prioritisation and ecological improvement interventions across 1000 on ground reserves under Council ownership. The tool scores to 100 comprising 10 metrics including landscape position, remnant size, connectivity, vegetation assemblage, fauna, threats and community values. The talk will be highly visual with GIS mapping layers presented and applications discussed.

Was the Cumberland Plains dominated by grassy woodland? And was fire involved in structural dynamics?

Associate Professor Scott Mooney, UNSW Nexus Fellow, Deputy Head of School, School of BEES, UNSW & Helen McCarthy, Honours Student, The University of Sydney

From lab to field: Can species germination niches predict seedling recruitment across climate regions and microhabitat conditions in the Cumberland Plain?

Chaminda Alahakoon, PhD Candidate, Hawkesbury Institute for the Environment, Western Sydney University

Global change threatens biodiversity worldwide. Seed germination and seedling establishment are critical for population growth; however, we lack a fundamental understanding of how species from diverse functional types (FTs) and habitats respond to temperature and water availability. In this study, we characterised temperature and water-availability niches for seed germination in 28 species representing different functional types (trees, shrubs, grasses, and forbs) and vegetation types (grassy woodlands, dry forests, and wet forests) within the Cumberland Plain (CP). We extended our analyses to identify broader temporal and spatial shifts in germination potential and tested how temperature and water availability contribute to seedling emergence and survival at the microhabitat level under field conditions. Germination niches of CP species were highly diverse. Germination windows narrowed through time under a high-emission climate scenario to 2100. Significantly stronger declines in germination potential over time were observed in shrubs and trees compared with ground cover, and in warmer, drier parts of the landscape. Our field experiment confirmed the importance of species’ germination niches for seedling emergence. Seedling recruitment was determined by current soil temperature and moisture in the field. However, species showed differential responses to microhabitat conditions (i.e. leaf litter and canopy cover) across climate regions. Our findings indicate that fundamental germination niches measured in the laboratory can predict species recruitment in the field. These findings highlight the importance of microhabitat and immediate climatic conditions in determining seedling emergence and survival. Insights from our study allow us to identify optimal sowing times, assess germination risks, and determine species-specific microhabitat requirements for seedling recruitment across the landscape and into the future.

Interactive Effects of Climate Change and Habitat Fragmentation on Plant Performance and Flammability

Zahra Emlaei, PhD Candidate, Hawkesbury Institute for the Environment, Western Sydney University

Climate change and habitat fragmentation can alter the likelihood and behaviour of fire. Fragmentation creates isolated patches of vegetation, each consisting of an interior and an edge. The edges of these fragments are influenced by a variety of environmental conditions due to their exposure to surrounding sparsely vegetated areas, which in turn affects plant ecology, plant physiology, and local microclimates.

In this study, we investigated the effects of climate change and habitat edge effects on plant flammability using both controlled glasshouse experiments and field-based assessments. In the glasshouse experiment, eight native Australian tree species were grown under two temperature regimes (25°C and 30°C) and two water treatments (well-watered and water-limited) for three months. Half of the plants were subsequently exposed to a five-day heatwave (35°C), followed by a 10-day recovery period under their respective growing conditions. We measured plant flammability and a range of leaf functional traits associated with plant stress and fire behaviour. To assess fragmentation and edge effects, we extended the study to 12 remnant patches of Cumberland Plain Woodland across the IBRA Cumberland subregion in Western Sydney, Australia. Within each remnant patch, three plot types were established: (1) interior forest plots, representing reference conditions; (2) green edge plots adjacent to grassland or agricultural land, reflecting fragmentation driven by agricultural expansion; and (3) urban edge plots bordering residential areas, reflecting fragmentation associated with urban development. The same leaf trait measurements were conducted across all field sites.

Our results showed that drought, warming, and heatwave exposure increased plant flammability in the glasshouse experiment. Similarly, field assessments demonstrated higher flammability at fragment edges compared with interior forest conditions. These findings suggest that climate warming and habitat fragmentation interact to exacerbate fire risk by altering plant physiological traits and increasing fuel flammability.

Understanding biodiversity change in Cumberland Plain remnants: what LiDAR, birds, and plants are telling us

Caitlin Dagg, PhD Candidate, Hawkesbury Institute for the Environment, Western Sydney University

The Cumberland Plain supports some of the most threatened grassy woodland communities in temperate Australia, yet our ability to monitor and manage their ecological condition landscape scales remains limited. This presentation synthesis findings from four chapter of my PhD examining how vegetation structure and urbanisation shape biodiversity across the Cumberland Plain Conservation Plan area.

Using airborne LiDAR data, ~1000 floristic survey plots, and 25 years of community-science bird observations, I investigated structure-biodiversity relationships and urban impacts on both plant and bird communities across ~2,600 km² of the peri-urban landscape. My analyses integrated remote sensing, community ecology, and functional trait frameworks to move beyond species counts towards a more complete understanding of ecological change.

Key findings span four themes. First, LiDAR-derived vegetation structure strongly predicts native plant diversity, but only when plant community are partitioned by growth form. Pooling species across strata obscures strong ecological signals, particularly for understorey species. Secondly, peri-urban bird communities are structured by multiple independent dimensions of urbanisation: vegetation complexity drives habitat specialist persistence, while road density exerts direct, vegetation-independent effects on assemblage composition. Thirdly, over 25 years, bird communities have undergone progressive functional homogenisation, shifting towards generalist, behaviourally flexible species, even where species richness appeared relatively stable. Finally, legacy urban exposure is a stronger driver of plant community change than contemporary urban cover, and vegetation structural complexity buffers remnant communities against urban-driven homogenisation, with structurally complex sites retaining native diversity and functional integrity even under moderate urban pressure.

Together, these findings have direct implications for how we assess remnant condition, design offset frameworks, and prioritise management. Structural complexity, not just species counts or cover extent, emerges as a key currency for conservation in this landscape.

Restoring woodland understories under changing rainfall: the roles of seeding diversity and soil layer

Paola Pisetta Raupp, PhD Candidate, Hawkesbury Institute for the Environment, Western Sydney University

Rainfall strongly shapes plant community structure and soil functioning, making it a key factor influencing the restoration of diverse understory vegetation in grassy woodlands. Yet, it remains unclear how seeding diversity shapes plant and soil responses to altered rainfall, and whether responses depend on soil layer. This is particularly relevant where topsoil removal is used to manage soil-borne legacies, altering the soil conditions in which plant communities establish. We explored how seeding diversity and soil layer mediate plant community and soil chemical, biological, and functional responses to altered rainfall in early restoration. We used a mesocosm experiment with upper (0-10cm) and lower (15-25cm) soils collected from a semi-degraded Cumberland Plain Woodland with mixed native and exotic understory species and no shrub or tree canopy. Native understory species were seeded as low (1 species), medium (4 species from 2 functional groups), and high (12 species from 4 functional groups) diversity treatments. After community establishment (112 days post-seeding), we simulated we simulated dry (-40%), average, and wet (+40%) rainfall scenarios using local historical rainfall. After 490 days, higher seeding diversity enhanced seeded species establishment and plant cover but did not buffer plant communities against rainfall variability. Belowground, higher seeding diversity increased microbial biomass nutrients and decomposition processes. Dry scenarios decreased plant cover, biomass, and richness, and increased plant composition dissimilarity across pots compared with average and wet scenarios. Wet scenarios were associated with higher dead plant biomass, soil C:N ratios, and microbial biomass nutrients, and lower nutrient availability than dry scenarios, suggesting stronger turnover and biological uptake. Soil depth modulated effects of seeding diversity and rainfall, with generally stronger plant and soil changes in upper soils. This study shows how seeding diversity may interact with rainfall and soil state to shape plant community development and soil functioning, informing restoration under climate variability.

Associate Professor Paul Rymer, Lead Investigator Cumberland Plain Research Program, Hawkesbury Institute for the Environment, Western Sydney University