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Changes in vegetation cover and dune mobility of Woolamai dune fields on the southeast coast of Australia were quantified based on a time series of aerial imagery (1939 to 2020). Results showed that the dune fields have shifted from nearly all bare sand (with <5% vegetation cover) to a new quasi‐equilibrium state, being almost fully stabilized by vegetation (>80%) from 1939 to 2020. Three temporal stages of vegetation change were identified, namely: (I) early expansion over 1939–1975; (II) rapid growth from 1976 to 2010; and (III) recent 'quasi‐equilibrium' state in 2010–2020. In stage I, complex impacts of climate and human activities co‐existed with uncertainty of the dominant factor. In this early stage, vegetation growth was constrained to the low and sheltered areas, indicating the influence of topography. Rapid vegetation growth took place in 1976–2010 (stage II), during which a re‐vegetation programme combined with favourable climate conditions promoted vegetation growth. In the last decade (stage III), vegetation might have reached a new quasi‐equilibrium when the vegetation almost reached a maximum. The slight loss of vegetation could be attributed to weed control and an unfavourable climate for growth (drier and windier) in Woolamai dune fields. This study showed that variations in vegetation cover and dune mobility through time are not simply linked to a single factor but depend on the occurrence of multiple factors (e.g. topography, climate and human activities) that promote stability, or alternatively, mobility of the dune system. This research contributes to expanding our understanding of the complexity of the bio‐geomorphologic dynamics in dune fields. It also provides detailed observational evidence for the historical trajectory of vegetation expansion from the bare dune fields to a fully stabilized state, which can be used to verify and refine models for other similar dune sites. [ABSTRACT FROM AUTHOR]

Abstract: Invasive vegetation species can lead to major changes in the geomorphology of coastal systems. Within temperate estuaries in the southern hemisphere, especially Australia and New Zealand, the cordgrass Spartina spp. has become established. These species are highly invasive, and their prolific growth leads to the development of supratidal environments in formerly intertidal and subtidal environments. Here, we quantified the impact of Spartina invasion on the geomorphology and sequestration capacity of carbon in the sediments of Anderson Inlet, Victoria, Australia. Spartina was first introduced to the area in the 1930s to aid in land reclamation and control coastal erosion associated with coastal development. We found that Spartina now dominates the intertidal areas of the Inlet and promotes accretion (18 mm/year) causing the formation of over 108 ha of supratidal islands over the past 100 years. These newly formed islands are calculated to potentially contain over 5.5 million tonnes of CO2 equivalent carbon. Future management of the inlet and other Spartina‐dominated environments within Australian presents a dilemma for resource managers; on the one hand, Spartina is highly invasive and can outcompete native tidal marshes, thereby warranting its eradication, but on the other hand it is likely more resilient to rising sea levels and has the potential for carbon sequestration. Whether or not the potential advantages outweigh the significant habitat change that is anticipated, any management strategies will likely require additional research into costs and benefits of all ecosystem services provided by Spartina including in relation to nutrient cycling, shoreline stabilisation, and biodiversity as well as in response to the longevity of carbon found within the sediments. [ABSTRACT FROM AUTHOR]

The removal of invasive species is common in restoration projects, yet the long-term effects of pest management programs are seldom assessed. We present results of a long-term program to remove the invasive species Lupinus arboreus (lupin) from sand dunes in New Zealand. We evaluate the response of plant communities to lupin removal, by comparing total plant cover, the cover of non-native and native plant species, and species richness between sand dune sites where lupin removal has occurred, not occurred, and where lupin has never been present. Neither lupin presence nor removal had a significant impact on the foredune environment. Following removal, total and other non-native plant cover remained higher, and the cover of several native sand dune species remained lower compared with uninvaded sites in the deflation and backdune environments. These changes can be attributed to persistent effects associated with the invasion of lupin, but have also developed in response to lupin removal. The results of this study have implications for restoration projects in sand dunes. Pest management alone is unlikely to be sufficient to restore plant communities. Given the difficulties in restoring plant communities once an invasive species has established, managers should prioritize actions to prevent the spread of invasive species into uninvaded areas of sand dunes. Finally, the response to lupin invasion and removal differed between dune habitats. This highlights the importance of tailoring a pest management program to restoration goals by, for example, prioritizing areas in which the impacts of the invading species are greatest. [ABSTRACT FROM AUTHOR]