Abstract. Drawing on the experience and lessons of wetland researchers and managers in Australia and New Zealand, we examined the implications of climate change for wetland policy and management, and identified potential adaptation responses and the information needed to support these. First, we considered wetland vulnerability to climate change, focusing on wetland exposure and sensitivity. We then outlined the existing policy context for dealing with climate change, with an emphasis on the Ramsar Convention on Wetlands. We then considered how the objectives and targets for wetland management can be set in the face of climate change, how management can be adapted to climate change given the uncertainties involved, and how we can monitor and evaluate wetland condition in the face of climate change. We concluded with a set of principles to guide adaptation of wetland conservation and management policy to climate change.

Aims: Aerially applied glyphosate is an economic tool to deal with large areas of invasive plants. However, there are few studies investigating non-target effects or rates of reinvasion, particularly over multi-year time frames. The aims were to evaluate the effectiveness of aerial application of glyphosate for control of dense stands of the invasive grey willow Salix cinerea, and determine the vegetation trajectory over the subsequent 2 yr.Location: Whangamarino Wetland, Waikato, New Zealand.Methods: A before-after control-impact (BACI) experiment was conducted in a Ramsar-listed wetland in New Zealand. Effects on S. cinerea cover, canopy light interception and non-target damage were monitored over a 7.1 ha experimental area prior to, and for 2 yr following, aerial application of glyphosate. Vegetation classification, ordination and species richness analyses were undertaken to describe community-level effects.Results: Aerial application of glyphosate to an established willow canopy was effective in reducing cover to <5% on average for up to 2 yr post-spray when assessed using 100 m 2 vegetation survey plots. Smaller 1 m 2 plots were more sensitive for detecting willow reinvasion, which was noted from 1 yr post-spray. Collateral damage to non-target sub-canopy species was generally minimal, except for the native tree fern Dicksonia squarrosa, which showed marked reductions in cover and no recovery over the study period. Species richness was higher in sprayed plots post-spray and a shift towards a native Carex-dominated sedgeland community was detected.Conclusions: Aerial application of glyphosate to a dense canopy of mature willow was effective in reducing the cover and dominance of this invasive wetland tree species. Minimal collateral damage occurred, facilitating recovery and expansion of a native sedgeland community. The risk of secondary invasion did not eventuate, although exotic species richness spiked in the year following spraying. Sedgelands are susceptible to willow reinvasion via seed, so longerterm trajectories will diverge depending on management intensity. Using currently available tools, the management options are either repeated cycles of herbicide application to redirect the trajectory from reinvasion to short-statured sedgelands, or intensive initial management to establish an alternative, more resilient trajectory to native wetland forest.

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Previous studies of the N:P ratio in wetland plants have been carried out in northern hemisphere wetlands where atmospheric nitrogen deposition is higher. There is little research on foliar N:P ratio as a potential indicator of nutrient limitation in vegetation communities in southern hemisphere wetlands. This study aimed to redress this knowledge gap and answer the following questions: how well does the plant tissue nitrogen to phosphorus (N:P) ratio predict wetland plant community nutrient limitation, as indicated by vegetation standing stocks and below‐ground biomass, in southern hemisphere fens? Secondly, what are the impacts of realistic upper levels of farm nutrient run‐off on natural montane fen vegetation? Low (35 kg ha−1 year−1) and high (70 kg ha−1 year−1) levels of nitrate‐N or ammonium‐N with and without P (20 kg ha−1 year−1) were added to 81 vegetation plots over a period of 2.75 years. Species composition, plant nutrient status, and above‐ground live vegetation standing stocks were assessed after 3 years, and below‐ground biomass after 2 years. Plant tissue analysis suggested the community was N limited or N and P co‐limited; we found greater standing stocks of vegetation in plots treated with 70 kg ha−1 year−1 ammonium‐N, indicating N limitation. No difference between other treatments was found in above‐ground standing stocks or below‐ground biomass. Plant species cover increased in both high N treatments, consistent with N limitation. These changes in plant species cover were accompanied by significant decreases in species richness in both high N treatments. Native species dominated the vegetation and this was unaffected by nutrient addition (90% cover). This is one of the first studies to test and find support for the N:P ratio in southern hemisphere wetlands. Observed declines in species richness after N fertilisation in an N‐limited fen suggests increased N may pose risks to austral wetlands. Responses by plant communities (changes in composition, biomass) to lower levels of nutrient addition may require longer periods of fertilisation to be apparent in slow growing ecosystems.