Climate change is altering species’ range limits and transforming ecosystems. For example, warming temperatures are leading to the range expansion of tropical, cold-sensitive species at the expense of their cold-tolerant counterparts. In some temperate and subtropical coastal wetlands, warming winters are enabling mangrove forest encroachment into salt marsh, which is a major regime shift that has significant ecological and societal ramifications. Here, we synthesized existing data and expert knowledge to assess the distribution of mangroves near rapidly changing range limits in the southeastern USA. We used expert elicitation to identify data limitations and highlight knowledge gaps for advancing understanding of past, current, and future range dynamics. Mangroves near poleward range limits are often shorter, wider, and more shrublike compared to their tropical counterparts that grow as tall forests in freeze-free, resource-rich environments. The northern range limits of mangroves in the southeastern USA are particularly dynamic and climate sensitive due to abundance of suitable coastal wetland habitat and the exposure of mangroves to winter temperature extremes that are much colder than comparable range limits on other continents. Thus, there is need for methodological refinements and improved spatiotemporal data regarding changes in mangrove structure and abundance near northern range limits in the southeastern USA. Advancing understanding of rapidly changing range limits is critical for foundation plant species such as mangroves, as it provides a basis for anticipating and preparing for the cascading effects of climate-induced species redistribution on ecosystems and the human communities that depend on their ecosystem services.

Aim: The climate change‐induced transition from grass‐dominated marshes to woody‐plant‐dominated mangrove forests has the potential to impact the ecosystem goods and services provided by coastal wetlands. To better anticipate and prepare for these impacts, there is a need to advance understanding of future changes in mangrove distribution and coastal wetland vegetation structural properties due to warming winters.Location: Southeastern United States.Time Period: Recent (1981–2010) and future (2071–2100).Major Taxa Studied: Coastal wetland vegetation.Methods: We estimated changes in mangrove distribution and coastal wetland vegetation structure using known climate‐ecological relationships, recent climate data for the period 1981–2010, and future projected climate data for the period 2071–2100. We quantified potential changes in mangrove presence, mangrove relative abundance, coastal wetland vegetation height, and coastal wetland vegetation aboveground biomass under two Shared Socio‐Economic Pathway scenarios (SSPs; SSP2‐4.5 and SSP5‐8.5), which correspond to intermediate and high greenhouse gas emissions scenarios, respectively.Results: Our analyses indicate that mangrove presence and relative abundance will dramatically increase in the northern Gulf of Mexico and the southeast Atlantic coast of the United States, particularly under the high emissions scenario. Because of the higher stature of mangroves relative to salt marsh vegetation, this expansion will cause a transformative change in coastal wetland vegetation height and aboveground biomass in many areas. However, along the arid southern Texas coast, low precipitation and high salinities are expected to constrain mangrove expansion and growth.Main Conclusions: Our results show where and to what extent climate change, in the form of winter temperature warming, is projected to enable the transition from shorter, grass‐dominated salt marshes to taller, woody plant‐dominated mangrove forests in the southeastern United States, with consequent impacts on ecosystem goods and services.

Ecological restoration programs increasingly aim to provide socio-economic and environmental benefits. However, monitoring of socio-economic outcomes of these programs lags behind monitoring of ecological outcomes. Socio-economic methods are less established, managers have less experience, and metrics used vary, stymieing evaluation and adaptive management. Here we demonstrate that logic models and stakeholder engagement can be used to identify core socio-economic metrics across various types of restoration, focusing on coastal restoration in the Gulf of Mexico. Across four major restoration types (oyster restoration, habitat restoration, recreation enhancement, and water quality improvement), core metrics were identified as changes in jobs, restoration expenditures, recreational activity, cognitive function, and subjective well-being. These metrics can provide a starting point for increased and more consistent monitoring of socio-economic outcomes. The collaborative, science-based, and replicable process we developed to identify core metrics can be applied to other ecosystems and management actions to expand monitoring and evaluation of socio-economic impacts.

With coastlines becoming increasingly urbanised worldwide, the economic risk posed by storm surges to coastal communities has never been greater. Given the financial and ecological costs of manmade coastal defences, the past few years have seen growing interest in the effectiveness of natural coastal “defences” in reducing the risk of flooding to coastal properties, but estimating their actual economic value in reducing storm surge risk remains a challenging subject.In this study, we estimate the value of mangroves in reducing annual losses to property from storm surges along a large stretch of coastline in Florida (USA), by employing a catastrophe modelling approach widely used in the insurance industry. We use a hydrodynamic coastal flood model coupled to a property loss model and a large property exposure dataset to estimate annual economic losses from hurricane-driven storm surges in Collier County, a hurricane-prone part of Florida. We then estimate the impact that removing mangroves in the region would have on average annual losses (AAL) caused by coastal flooding. We find that mangroves reduce AAL to properties behind them by over 25%, and that these benefits are distributed very heterogeneously along the coastline. Mangrove presence can also act to enhance the storm surge risk in areas where development has occurred seaward of mangroves.In addition to looking at annual losses, we also focus on the storm surge caused by a specific severe event in Florida, based on Hurricane Irma (2017), and we estimate that existing mangroves reduced economic property damage by hundreds of millions of USD, and reduced coastal flooding for hundreds of thousands of people.Together these studies aim to financially quantify some of the risk reduction services provided by natural defences in terms of reducing the cost of coastal flooding, and show that these services can be included in a catastrophe modelling framework commonly used in the insurance industry.

We examined the influence of mangrove encroachment into salt marsh areas along the northern Gulf of Mexico (USA) on waterfront property owners' perceptions of coastal health and preferences for shoreline management. Using mail‐in and online surveys, we targeted over 3000 waterfront property owners across four jurisdictions experiencing or anticipating mangrove encroachment. Our findings revealed a nuanced perception of coastal health, with many respondents recognizing the potentially environmental impacts of mangrove encroachment but favouring low‐cost management strategies, such as maintaining current shoreline or passive monitoring. This reluctance to engage in active management highlights a perception‐behaviour gap, likely influenced by the gradual nature of mangrove transitions, which diminishes urgency for active intervention. Socio‐demographic factors such as age, gender, income, residency and reliance on coastal resources significantly shaped preferences for shoreline management and regional responses. These preferences varied across jurisdictions, reflecting the importance of incorporating localized community values into management decisions. Our findings highlight the need for a balanced approach to shoreline management that integrates ecological insights with the socio‐cultural priorities of local communities. By aligning adaptation strategies with regional perceptions and values, it is possible to protect individual properties while enhancing the long‐term resilience of coastal ecosystems under climate change pressures. Read the free Plain Language Summary for this article on the Journal blog.