Resilience and Adaptive Capacity of the Swan Coastal Plain Wetlands

An estimated 90% of the Swan Coastal Plain (SCP) wetlands, located in southwestern Australia, have been lost because of infilling or drainage. This loss continues despite the well-known causes, which include nutrient enrichment; the invasion of exotic flora and fauna; loss of fringing vegetation; and altered hydrological regimes caused by groundwater abstraction; urbanization; and a drying climate. Further loss is expected with climate change exacerbating the undesirable ecosystem changes of remaining wetlands. In this study, we consider these wetlands as examples of social-ecological systems (SES) which are characterized by a close interaction of the ecosystem with the social system. We take the theory of resilient SES as a starting point to identify the adaptive capacity and resilience of the wetlands. We argue that resilience provides a useful framework to analyze adaptation processes and to identify appropriate policy responses. We explore incremental adjustments and transformative action and demonstrate that policy responses arise across multiple scales and levels of jurisdiction and institution. By applying the theoretical framework of resilience to the SCP wetlands, we identified (un)desired ecosystem states of wetlands (hydrology and ecology) through different set of policy actions. Our results show that current wetland management is inadequate to maintain the ecosystem's functioning. We recommend cross-jurisdictional collaboration and the use of conceptual eco-hydrological models to depict gradual ecological change and types of regime shifts (thresholds, hysteresis, and irreversible changes). The different adaption options inform decision-makers to adequately adapt wetland management practices when uncertainty in ecosystem responses exist. Empirical data on how multiple jurisdictions operate and decide could help to further support decision-making. With this research we aim to narrow the science-policy interface which depends on corresponding cross-jurisdictional and institutional responses to coordinate wetland management policies and actions.

Eurasian Hobby Falco subbuteo: A review of recent records from Western Australia and Australian external territories

All Australian records of the Eurasian Hobby Falco subbuteo are summarised. Before 2016, the only Australian records of the Eurasian Hobby were on external territories to the north-west of the mainland. Each year between 2016 and 2021 a single Eurasian Hobby was observed as an austral summer visitor to the Swan Coastal Plain in south-western Western Australia. These sightings involved an adult in 2016, 2019 and 2020, and single immature birds in 2017–2018. The age of the Hobby seen in 2020–2021 was undetermined. As it appears that multiple individuals have been recorded across years, it is likely that the species is now more than just an accidental vagrant to Australia.

When urban stormwater meets high groundwater

New land releases in the Perth Region on Western Australia’s Swan Coastal Plain are increasingly constrained by seasonally high groundwater (within 4m of the land surface). The measurement, modelling, and management of the effects of urbanisation in these high groundwater environments remains a challenging problem. To address this problem, the Cooperative Research Centre for Water Sensitive Cities (CRWSC) funded the “Knowledge-based water sensitive city solutions for groundwater impacted developments” Integrated Research Project, IRP5. In 2019, this project convened an Expert Panel to assess best-practice, and make recommendations to land development, engineering consulting, regulatory and advisory stakeholders. The Expert Panel explored strategies for groundwater risk assessment and provided technical guidance for measuring, modelling and predicting changes in groundwater as urbanisation progresses. It also obtained extensive input from stakeholders on the need to reduce the costs and risks of urban development in sites with high groundwater. In this paper, we argue that, by integrating technical best-practice groundwater assessments with design innovations and reforms to governance, urban development on high groundwater sites on the Swan Coastal Plain can minimise the current reliance on large volumes of sand fill. Although challenging, shifting to a low-fill development paradigm would represent a triple-bottom-line “win” for developers, homeowners and the environment.

Styleworts under the microscope: a taxonomic account of Levenhookia (Stylidiaceae)

A taxonomic revision of the Australian endemic genus Levenhookia R.Br. (Stylidiaceae) recognises 12 species, of which L. aestiva Wege, sp. nov. from south-western Australia is newly described. Levenhookia preissii (Sond.) F.Muell. is lectotypified and recircumscribed as a Swan Coastal Plain endemic, resulting in its addition to the Threatened and Priority Flora List for Western Australia. Lectotypes are also selected for L. dubia Sond., L. leptantha Benth., L. sonderi (F.Muell.) F.Muell. and L. stipitata (Benth.) F.Muell. ex Benth. Verification of herbarium records has expanded the known distribution of L. murfetii Lowrie & Conran and L. pulcherrima Carlquist and has confirmed the widespread distribution of L. dubia across southern Australia including Tasmania, where it is currently listed as extinct-surveys based on information gleaned from historical collections may lead to its rediscovery in this State. Descriptions, distribution maps and photographs for all species are provided along with a key to species.

Implications of Banksia seed reward for conservation and management of Carnaby’s cockatoo on the Swan coastal plain, Western Australia

The food resource utilisation of six species of Banksia by the endangered Carnaby’s cockatoo (Calyptorhynchus latirostris) was investigated on the Swan coastal plain, Western Australia, over a 12-month period. The energy yield from the seeds harvested by the cockatoos was determined and the information was combined with data on the number of infructescences produced per hectare, the average seed yield per infructescence and the average rate of harvest of that species of seed by the cockatoos to calculate estimates of the number of infructescences required to support a single cockatoo per day under a range of scenarios. Over 65% of infructescences of each species of Banksia handled by the cockatoos were consumed for seed. Banksia sessilis had the largest number of infructescences and follicles manipulated by Carnaby’s cockatoos. The energy content of Banksia seed was 20–23 kJ g–1. Seed weight varied from 0.075 ± 0.016 (s.e.) g for B. attenuata to 0.007 ± 0.002 (s.e.) g for B. sessilis. The number of infructescences required to meet the birds’ daily energy intake ranged from 14 for B. grandis to 3821 for B. sessilis. The results have important implications for the continued capacity of the Swan coastal plain to support Carnaby’s cockatoos, for the future survival of obligate seeding Banksia spp. and for anthropogenic revegetation programs utilising Banksia spp.