This study used laboratory column microcosms with River Murray (Australia) wetland soils and water to examine how drying-rewetting (DRW) and river red gum (Eucalyptus camaldulensis) litter inputs interactively affect nitrogen (N), phosphorus (P), and carbon dynamics across soil, pore water, and overlying water. We quantified N and P species and dissolved organic carbon (DOC) under two water regimes (constant submergence versus DRW) with and without litter addition to resolve cross-compartment responses at the aquatic-terrestrial interface. DRW enhanced net inorganic-N mobilization, resulting in pronounced post-rewetting pulses in pore-water and overlying-water N (especially NH4+) compared to constant submergence, with concentrations gradually converging during prolonged inundation. Conversely, total P and inorganic P (Pi) were higher under constant submergence, consistent with sustained reducing conditions promoting P release in solution. Although litter inputs did not substantially alter total nutrient levels in overlying water, they shifted pore-water chemistry by increasing the proportion of inorganic P and strongly elevating DOC. Following rewetting, DOC increased sharply in litter-amended treatments, ~ 2.9-fold in overlying water and ~ 16.8-fold in pore water, compared with no-litter treatments. Litter addition also reduced nitrate availability in soil and pore water during resubmergence, consistent with stronger microbial N retention and/or NO3− consumption under rapidly re-established reducing microsites after rewetting. Overall, DRW and litter inputs interact to amplify short-lived C and N pulses while modifying P speciation, with implications for predicting nutrient availability and water-quality risk in wetlands experiencing increasingly variable hydrological regimes.

Wetlands are some of the most productive and important ecosystems in the world. Within the Great Salt Lake ecosystem of the Pacific Flyway, North America, wetlands provide essential food resources for migratory waterbirds and are essential for their population viability. We conducted waterbird exclosure studies in a sheet flow wetland in Farmington Bay of Great Salt Lake focusing on predation effects on the most dominant food item, the ecosystem engineers, chironomid larvae. We found that waterbirds focused on larvae in larger size classes and that chironomid larvae densities, biomass and energy values per unit area were some of the highest estimated in the Great Salt Lake ecosystem. Chironomid larvae appeared to have bottom-up control of waterbirds, while waterbirds’ size selective feeding activity and excrement contributed to what we call a ‘density-dependent, mutualistic positive feedback loop’ that can affect the entire ecosystem function. These findings can be incorporated into ecosystem function models and can be used by managers concerned with protection of these crucial wetlands.

Wetlands are among the most productive and biodiverse ecosystems in the world, yet they are also the most threatened. These vital habitats play a crucial role in mitigating climate change. Although most freshwater wetlands occur on private property, limited research exists on landholder perceptions of their ownership and management. We interviewed landholders who participated in a wetland restoration program. Our interviews explored motivations and barriers to participation and the impact of climate change, if any, on landholders. We conducted a thematic analysis of interview transcripts. Our analysis revealed three major themes. First, participants were motivated by the intrinsic value of nature, focusing on benefits to native flora and fauna rather than personal gain. They expressed strong emotional connections to nature and a sense of stewardship. Second, the removal of bureaucratic, financial and practical barriers by a knowledgeable local facilitator was important for participation. Third, participants acknowledged the tension between agricultural practices and the needs of nature, striving to balance these competing demands. Although climate change was recognised, the primary motivator was restoring natural ecosystems. Restoring freshwater wetlands can help policymakers achieve international and domestic biodiversity goals by aligning conservation programs with landholders’ values. Employing local facilitators with intimate knowledge of the community and ecosystem can enhance program engagement. Additionally, integrating agricultural and environmental needs, such as through agritourism, can further support biodiversity, and the economic and mental resilience of landholders.

Understanding how mangroves respond to natural and anthropogenic pressures at global distributional range limits informs protection and restoration strategies. Mangroves along the South African coastline are at one of the most southerly global distribution limits. These endangered ecosystems have been studied for more than 25 years to determine their vulnerability and responses to global climate change. This study assessed the drivers of change in mangrove area cover, species composition and population structure between 2011 and 2021 in 17 estuaries. There was a net increase in mangrove cover over this 10-year period of 3 ha and this was attributed to natural regeneration along tidal sand banks and into areas previously covered by salt marsh. Bruguiera gymnorrhiza was the only mangrove tree species found in all the estuaries, Avicennia marina occurred in 71% and Rhizophora mucronata in 47% of all estuaries. Major anthropogenic pressures that reduced mangrove cover and caused shifts in population structure were wood harvesting, livestock browsing and trampling. Anthropogenic pressures have persisted since 2011 resulting in structural mangrove degradation indicated by a decrease in seedling and sapling density and increase in canopy gaps. These results provide input to the National Biodiversity Assessment and are relevant to the implementation of the Global Biodiversity Framework informing site specific restoration strategies. The research also informs global studies on climate-driven range shifts; mangrove expansion is occurring, but this is slow and influenced by local pressures. The study recommended that adaptive management and monitoring frameworks are used to track mangrove changes.

Abstract The Ramsar Convention requires signatory countries to describe, ‘at the time of listing’, the ecological character of wetlands nominated as internationally important. It also requires nations to maintain the ecological character. While the definition of ecological character by the Convention, is ‘the combination of the ecosystem components, processes and benefits/services that characterize the wetland at any given point in time’ it has been misinterpreted that the wetland needs to be maintained in the condition observed at the time the site was listed . As the Convention was established, in 1971, with the purpose of arresting the loss and degradation of wetlands, it stands that many wetlands were degraded when the convention was signed, and even more so when sites were listed. Adherence to a time-of-listing baseline precludes options to restore wetlands to a previous state. It also runs contrary to the Guidelines for Ecological Restoration which advocate for an appropriate indigenous baseline as a target. There is provision in the Convention to revise the target character if evidence of a different baseline becomes available. This was applied in the case of Chilika Lagoon (India) where the lagoon was opened to the sea to recover a brackish past state. In the Gippsland Lakes (Australia) it is recognised that an artificial opening to the ocean has changed the character yet management pursues the state described at the time of listing. Historical and palaeoecological evidence can provide a means to identify a raft of indigenous states that may be more appropriate targets for management.