Policy

Historic and projected climate change in addition to constantly evolving agricultural practices make it difficult to disentangle the influence of climate and land use decisions on Canadian Prairie streamflow regimes and water availability. This paper aims to describe the development and application of a basin classification-based virtual model platform that can be used to enhance understanding of how climate and wetland drainage each control Prairie basin hydrology. Each 100 km2 basin in the Canadian Prairie ecozone was classified into one of seven types using a hierarchical clustering of principle components. The modelling platform has been applied to investigate the hydrological sensitivity of two Prairie basin classes (High Elevation Grasslands and Pothole Till) to changes in climate and wetland extent. The experiments revealed that snowpacks are highly sensitive to changes in climate, and this varies geographically and between the two classes. Spring maximum snow water equivalent can decrease 9% per degree °C of warming, but this can be offset with increases in mean annual precipitation. Wetland drainage enhances annual streamflow volume, more so during wet conditions. The platform is designed to expand and provide linkages to water chemistry, groundwater and biodiversity models to generate information on how multiple systems may respond to stress. These results are being developed in partnership with stakeholders, and communicated to decision-makers to inform agricultural beneficial management practices and wetland management. n

Presented during S4: Novel approaches to quantifying synergistic interactions between climate and land-use change on prairie-pothole wetlands II, 6/1/2021 10:55AM- 12:45PM ET

NEW INSIGHTS ON THE ROLE OF WETLANDS IN CONFERRING WATERSHED HYDROLOGIC RESISTANCE

Creed, Irena, University of Saskatchewan Paltsev, Aleksey Ameli, Ali Lane, Charles Golden, Heather Leibowitz, Scott Hydrologic resistance is a watershed’s ability to absorb or contend with disturbances while maintaining or quickly recovering hydrologic functional traits. Here, we explore the importance of vulnerable waters – such as wetlands – in conferring a watershed’s hydrologic resistance at national scales. We used a framework that quantifies and compares the hydrologic values of wetlands of different types (surface/subsurface), locations (far or near to stream), and connectivity (low versus high connectivity) to explore the relationships between wetlands and hydrologic resistance in relatively undisturbed catchments throughout the conterminous United States. We measured hydrologic resistance as the degree to which discharge (Q) is coupled with precipitation (P) (i.e., the slope of the P vs. Q correlation) – watersheds that store water and release it gradually to the stream have a high resistance (low P-Q correlation). In contrast, watersheds that do not hold water and release it quickly to the stream have low resistance (high P-Q correlation). We considered factors that influence the way a watershed collects, stores and releases water, and links P to Q. We included: (1) “distal factors” such as estimated water balance as indicated by the theoretic energy (potential evapotranspiration (PET)/P) and water (actual evapotranspiration (AET)/P) limits and synchrony between P and temperature (T) phases; and (2) “proximal factors” [e.g., the potential volumetric storage capacity of a wetland, the residence time of water stored within it, the location of a wetland to a nearby stream – and its hydrologic connectivity to the stream]. As expected, we found that for watersheds that are in phase, where at the extremes, peak P and peak temperature (T) are in July, low connectivity wetlands conferred higher hydrologic resistance. However, not expected, we found that for watersheds that are out of phase, where at the extremes, peak P is in January, and peak temperature is in July, low connectivity wetlands conferred lower hydrologic resistance. Wetlands vary in the manner in which they affect hydrologic resistance, based on their hydrologic connectivity and P and T synchrony. Our findings led us to develop new conceptual models of the role of wetlands in conferring watershed hydrologic resistance that are being further explored. n

Presented during CS5: Worldly Wetlands II, 6/3/2021 6:55PM - 8:45PM ET

TRANSBOUNDARY WETLANDS: EXPLORING FORMAL MECHANISMS FOR COOPERATION

Rosenblum, Zoe, Oregon State University and IHE-Delft Institute for Water Education Despite increased understanding of the benefits of wetlands, global wetland area continues to decrease. Wetlands are being lost at an alarming rate, and with them, biodiversity, floodwater storage, water purification, and countless other functions. There is little information available about mechanisms to manage transboundary wetlands.

While the Ramsar Convention is one international mechanism for wetland governance, there are very few cases in which all riparian parties have jointly designated a Transboundary Ramsar Site. Most research on transboundary wetlands explores specific conflicts or management issues or argues for or against the Ramsar Convention as a legal tool to manage wetlands. However, little research explores institutions for managing transboundary wetlands. Furthermore, while there is much evidence that freshwater resources are a source of cooperation, there is emphasis on rivers and wetlands are largely absent from the discourse. This research employs document analysis, coding, and spatial analysis to explore how transboundary wetlands are managed. The products of this research are: a database of the world’s transboundary wetlands; an in-depth analysis of the management of the Wadden Sea, Okavango Delta, and the Hamoun Wetlands; and a discussion of factors that may contribute to cooperation over transboundary wetlands. n

Presented during CS5: Worldly Wetlands II

YOUTH ENGAGED IN WETLANDS: A GLOBAL NETWORK TO CONSERVE WETLANDS, TOWARDS YOUTH REPRESENTATION IN THE RAMSAR CONVENTION

E. Sanchez, Maria, University of Saskatchewan Sharma, Bidhya Jones, Dylan Allély-Fermé, Elise Lobato-de Magalhães, Tatiana The continuing and alarming decline of wetlands worldwide constitutes an urgent call-to-action for all generations to join efforts in conserving and using wetlands wisely. Youth Engaged in Wetlands (YEW) is an international network whose mission is to provide a global platform for youth worldwide, to enable and empower them to promote wetland conservation. YEW aims to build greater sense of ownership of the Ramsar Convention on Wetlands’ mission among youth, through networking and capacity building. YEW’s vision is to be the leading youth network at the global level for wetlands and a valued stakeholder for the Ramsar Convention. The YEW team is composed of students and young professionals working on a range of wetland types worldwide. Following the Ramsar Convention’s 13th Conference of the Parties (COP) in Dubai (United Arab Emirates), YEW created a strategy for the period from 2019 until 2021 when the Convention will hold its 14th COP in Wuhan (China). The strategy is based on four objectives. Objective 1 involves the development, management, and coordination of this international network. Objective 2 includes establishing a knowledge-sharing platform to increase the understanding of the challenges and opportunities for youth engagement in the Ramsar Convention and wetland conservation. Objective 3 aims to build participation of youth in decisionmaking and establish a formal mechanism for intergenerational cooperation within the Ramsar Convention and beyond. Finally, objective 4 strives to build networks with youth and their organizations, and contribute to communicating youth stories and the importance of wetlands. The network is committed to interdisciplinary and intergenerational collaboration to support the mission to save wetlands worldwide. n

Presented during CS9: Policy, Tuesday, June 8, 2021 10:55AM - 12:45PM ET

ROLLBACK OF US FEDERAL WETLAND PROTECTIONS: IMPLICATIONS FOR WETLAND ACRES AND FUNCTIONS IN WISCONSIN

Miller, Nick, The Nature Conservancy Gries, Ashley Smith, Chris Kline, Joanne Wagner, John Jack, Loretha Bernnthal, Tom Waters of the US (WOTUS) rules define which wetlands and waterbodies receive federal protection under the Clean Water Act (CWA). These definitions have been debated in courts and subject to change since the CWA’s inception. The 2020 WOTUS Rule, called the Navigable Waters Protection Rule, is less restrictive than previous iterations, limiting CWA wetland jurisdiction to sites adjacent to—and typically annually inundated by—relatively permanent surface waters. These changes will eliminate federal regulatory protections for many wetlands and put at risk wetland services such as flood abatement, water quality protection, carbon storage, and shoreline protection. However, the extent of impact was not assessed during rule formation. Wisconsin’s Green Fire and The Nature Conservancy (TNC) conducted a case study to assess the likelihood of Wisconsin wetlands losing CWA protections using a GIS-based hydrogeomorphic approach. These data were developed earlier as part of Wetlands by Design, a statewide wetland ecosystem service assessment conducted by TNC and the Wisconsin Department of Natural Resources that considers wetland hydrologic inputs, outputs, water flow paths, and association with waterbodies using the LLWW Classification System. Results suggest 3.5 mil-

lion acres (55% statewide, ranging from 14% to 72% across Wisconsin’s HUC6 watersheds) or more of Wisconsin’s remaining wetlands would lose federal protection. These data also allow for estimation of the wetland area important for a range of ecosystem services that would no longer be protected under federal jurisdiction. Statewide, 2.5 million acres or more of wetlands that contribute to managing flood waters would no longer be federally protected, with northern Wisconsin watersheds most at risk. We recommend similar hydrogeomorphic modeling, nationwide, to assess wetland connectivity with adjacent and downstream waters and inform the development of a science based WOTUS Rule. Further, a broad array of wetland conservation activities can benefit from application of the LLWW Classification System and additional GIS-based assessment tools used in Wetlands by Design. n

Presented during S13: A Universal Declaration on Rights of Wetlands: Shifting our Paradigm Restores the Human-Wetland Relationship in Support of Wetland Restoration, Conservation and Wise Use, 6/10/2021 3:35PM - 5:25PM ET

CULTURAL, LOCAL COMMUNITY AND INDIGENOUS PEOPLES’ ISSUES FOR A DECLARATION OF THE RIGHTS OF WETLANDS

Simpson, Matthew, 35percent Pritchard, Dave Much of the recent growth in contemporary formal recognition of the rights of nature draws on improved understandings about the belief systems and traditional practices of Indigenous peoples and local communities (IPLCs). The cultural and linguistic heritage of IPLCs contributes to the world’s diversity. Their knowledge and practices have enhanced respect for the environment and natural resources, often offering models of sustainable approaches to water security, food security, health and well-being. Rights of wetlands can be an important component of enlightened and holistic approaches of this kind, which see the human species as part of the ecosystem rather than apart from it. Increasing evidence suggests that land demarcated as Indigenous Lands protects the natural environment through reduced rates of wetland degradation and deforestation, less habitat conversion and lower greenhouse gas emissions compared to surrounding areas. Traditional knowledge and management practices often play a significant role in protecting crucial habitats and the socio-ecological systems they support. The United Nations Declaration on Rights of Indigenous Peoples addresses the most significant issues affecting indigenous peoples - their civil, political, social, economic and cultural rights. A declaration of wetland rights needs to fit with this philosophy, and to support the wisdom and rights of IPLCs with respect to the landscape and their relationship with wetlands. This paper sets out some key ingredients of the required approach. n

Presented during S13: A Universal Declaration on Rights of Wetlands: Shifting our Paradigm Restores the Human-Wetland Relationship in Support of Wetland Restoration, Conservation and Wise Use

INNOVATING TO ADAPT TO CLIMATE DESTABILIZATION AND BIODIVERSITY COLLAPSE: A DECLARATION OF THE RIGHTS OF WETLANDS

Davies, Gillian, BSC Group, Inc./Tufts University Global Development and Environment Institute Finlayson, Max Despite establishment of the Ramsar Convention on Wetlands (1971), and many wetlands conservation and restoration efforts at national and sub-national levels, wetland loss and degradation continue apace, and are part of a larger trend in ecosystem and biodiversity loss and degradation. The current paradigm for conservation of wetlands is failing to meet stated goals. In the context of climate destabilization, the need to reverse these trends is urgent. Often led by local and Indigenous peoples, a global rights of Nature movement is shifting the ethical and legal paradigm for the human-Nature relationship. As wetland professionals, how can we respond to larger trends? A group of wetland and climate scientists, through the SWS Climate Change & Wetlands Initiative and Ramsar Section, proposes a Universal Declaration of the Rights of Wetlands with the goal of shifting our relationship with wetland ecosystems. Acknowledging inherent rights of wetlands and their legal personhood, as Indigenous people have done for millennia, and as many scientists and philosophers have done throughout history, returns to values and modes of thinking that modernity has typically pushed to the margins. In reconsidering our place in the community of beings making up the Earth community, we can restructure our relationships with wetlands. By embracing relational values with Nature, such as reciprocity, gratitude, responsibility, and acknowledgement of the personhood of Nature we shift decision-making away from exploitation, depletion, degradation and loss, and towards real conservation, restoration, re-wilding and remembering our integrated and relational presence as a part of Nature. n

Presented during S13: A Universal Declaration on Rights of Wetlands: Shifting our Paradigm Restores the Human-Wetland Relationship in Support of Wetland Restoration, Conservation and Wise Use

THE RIGHTS OF WETLANDS IN SUPPORT OF A SAFE CLIMATE AND EFFECTIVE WETLAND RESTORATION – THE CHARTER MODEL

Moomaw, Bill Wetlands are an integral component of the global ecosystem that connects through gas exchange with the atmosphere. Wetlands sequester carbon dioxide and respire both carbon dioxide and methane. They support large amounts of biological diversity including migratory birds that connect local wetlands to global biodiversity. Current attempts to declare that wetlands have a fundamental right to exist can learn from previous declarations on the rights of nature that have utilized the charter model. We will examine two examples, the World Charter for Nature (WCN) (1982) and the World Charter – 1999, and determine if either provides a suitable model for a declaration of the rights of nature. WCN contains strong statements on the value of nature, and defines five principles for conserving it. The Charter was engraved in bronze tablets that were placed outside the common meeting room of the General Assembly that endorsed it. The Earth Charter is a civil society initiative that has been endorsed by UNESCO and many societal groups including indigenous people and some representatives from government including mayors and other officials. It was proposed by Maurice Strong and Michael Gorbachev as the World Commission on Environment and Development was drafting Our Common Future in 1987, the report that defined sustainable development. In many ways it provides a template for more recent proposals for the Green New Deal in the United States and the Green Deal in Europe. Like those efforts, at creates a global order that links environmental conservation with socio-economic issues. This analysis seeks to determine whether either of these two charters provide a useful structure or precedent for a Declaration of the Rights of Wetlands. n

Presented during S13: A Universal Declaration on Rights of Wetlands: Shifting our Paradigm Restores the Human-Wetland Relationship in Support of Wetland Restoration, Conservation and Wise Use

WHY COULD A DECLARATION OF RIGHTS OF WETLANDS SUPPORT WETLAND WISE USE?

Davidson, Nick We face a recognised global biodiversity crisis. Wetlands are not exempt. In 1971, 50 years ago, the Ramsar Convention on Wetlands was established by governments because of then increasing concerns over wetland loss and degradation – and its impacts on wetland-dependent species. But since 1970 the area of wetlands has progressively continued to decline, through deliberate drainage and conversion, in all parts of the world. Deterioration in the state of our remaining wetlands is becoming progressively more widespread, including for designated Wetlands of International Importance (Ramsar Sites). Populations of freshwater species have declined since 1970 far more than species depending on other biomes. For wetlands, the world’s governments have not met their 2020 Aichi Targets for biodiversity. Nor are they on track to deliver the 2030 UN Sustainable Development Goals (SDGs) for wetlands. Yet governments are just continuing “business as usual”: in 2021 they are preparing to adopt yet another set of goals and targets, for 2030 – and the draft targets are very similar to previous targets. Nature conservation actions and protected area approaches for wetlands have failed to deliver, and will likely continue to fail: the drive for economic growth, rather than truly sustainable development, continues to over-ride achieving wetland wise use. So, we all need to change our mindsets and approaches and develop new paradigms to achieve such wise use. That’s what we are here to explore and discuss in this symposium. n

Presented during S2: Building Tribal Wetland Program Capacity and a National Framework for Advancement within the United States II, 6/1/2021 10:55AM- 12:45PM ET

STARTING AND SUSTAINING A TRIBAL WETLAND PROGRAM

Jones, Mike, Stockbridge-Munsee Community Many tribes have benefited from the development of a formal wetland program. A stand-alone program allows for a more targeted approach that incorporates wetlandspecific activities to effectively manage these valuable resources. Once a program has been developed, sustaining the program becomes a major and ongoing challenge in the face of funding, staffing, and time constraints. No two tribes or tribal wetland programs are the same, but programs can be run successfully and sustainably through careful planning, strategic thinking, communication, and creativity. This presentation will cover tips, strategies, challenges, and lessons learned to help guide any tribe that is considering starting a wetland program, or tribes focused on maintaining their program. It will include ideas and advice for funding, creating a Wetland Program Plan, developing partnerships, and utilizing resources available to tribes. n

Presented during S6: Wetland Wildlife in Natural, Managed, Reclaimed and Restored Wetlands II, 6/8/2021 10:55AM - 12:45PM ET

CONSERVATION EASEMENTS FOR “NATURAL RELATIVELY NATURAL HABITAT OF FISH, WILDLIFE, OR PLANTS, OR SIMILAR ECOSYSTEM” IN THE U.S. TAX CODE

Nyman, John, Louisiana State University Agricultural Center

Conservation easements allow landowners to transfer developmental rights to another organization that will not develop the land. Conservation easements are one answer to challenges to wildlife conservation posed by private land ownership. For example, the USDA Natural Resources Conservation Service (NRCS) enrolled over 2.7 million acres of wetlands on private lands. Most wildlife professionals probably believe that those easements, purchased with taxpayer’s money, contributed to wildlife conservation. A different program recently attracted negative attention. The U.S. Department of Treasury, Internal Revenue Service estimated that between 2010 and 2017, private investors used syndicated permanent conservation easements to claim $26.8 billion in charitable contribution deductions that lowered their federal income tax by approximately $10.6 billion. Unfortunately, a 2020 report by U.S. Senate, Committee on Finance identified numerous commercial valuations of land that appeared so inflated that they represented abusive tax shelters. A second problem may have developed with that program. Until 2018, there was little question what constituted “relatively natural habitat of fish, wildlife, or plants, or similar ecosystem” in the U.S. Tax code. In 2018 for example, the U.S. Tax Court ruled that a golf course “neither provides a habitat for rare, threatened, or endangered species nor is a natural area that contributes to the ecological viability of an adjacent National Forest.” I currently believe that most members of the Society of Wetland Scientists (SWS) and The Wildlife Society (TWS) would recognize the definition of “relatively natural habitat of fish, wildlife, or plants, or similar ecosystem” used in that decision. That decision was overturned in 2020 by the United States Court of Appeals for the Eleventh District. I currently believe that most members of SWS or TWS would not recognize definition of “relatively natural habitat of fish, wildlife, or plants, or similar ecosystem” used by the 2020 decision. I also believe that conservation easements will lack conservation value in the physical world if the 2020 definition used by the Court of Appeals persists. I urge wildlife professionals to be ready with amicus curiae brief summarizing the use of the terms “habitat” and “ecosystem” in conservation if the 2020 decision regarding “relatively natural habitat of fish, wildlife, or plants, or similar ecosystem” persists in the U.S. Tax Code. n

Presented during S8: Tropical wetlands and opportunities for climate change adaptation and mitigation – Scientific advancements and innovative tools II, 6/8/2021 10:55AM - 12:45PM ET

EFFECTIVENESS OF FINANCIAL INCENTIVES FOR MANGROVE PROTECTION AND DEVELOPMENT IN VIETNAM

Thu Thuy, Pham, CIFOR Dao Thi Linh, Chi Pham Duc, Chien Nguyen Viet, Hoa Trang Dao Le, Huyen Hoang Tuan, Long Vu Tan, Phuong Thuy Pham, Thu Nguyen Dinh, Tien Nguyen Van, Truong Mangroves play an important role in providing goods (forest products and fishery resources) and environmental services, both to the marine environment and people. However, in Vietnam, mangrove forests have been threatened by economic pressures and climate change. Since 1990s, the government of Vietnam has issued a large number of policies and donors have funded a large number of projects promote mangrove conservation activities. These policies and projects aim to create financial incentives to motivate forest owners to protect mangroves. However, there is a lack of analysis on their effectiveness to inform future policies. Using case studies from Thai Binh, Quang Ninh and Thanh Hoa provinces Vietnam, this papers aims to address these knowledge gaps and analyze both opportunities and constraints for mangrove protection and management in Vietnam. This study has adopted a mixed research methodology. In total, 240 people participated in focus group discussions, 604 households participated in the household surveys. We also conducted 24 key informant interviews with local authorities, non-governmental organizations (NGOs) and community representatives. Findings were presented and verified at a national consultation workshop with 42 participants as well as a provincial consultation workshop with 32 participants. Our findings show that many policies and projects offer social and economic incentives for mangrove protection. However, they are impeded by insecure tenure, land grabbing, elite capture and inequitable benefit-sharing. Several other factors constrain mangrove protection at the institutional level: overlapping and unclear mandates and responsibilities among government agencies at central, provincial and multilateral level, accessing to information on both policies and projects is difficult for local people. Moreover, the monitoring and evaluation (M&E) systems, incentives and disincentives designed by policies and projects, also have major drawbacks. These include low enforcement and compliance, unclear penalty mechanisms and a lack of requirement to replant mangrove forests after they are illegal cut. Policies and projects strongly emphasize and create incentives to replant mangrove forests, rather than to maintain and conserve existing mangrove forest areas. Incentives are also designed

to compensate local labor costs for replanting mangrove or patrolling activities, rather than addressing the direct drivers of deforestation and degradation. The study also reveals that local willingness to pay is driven and determined by effective law enforcement; transparent and accountable financial management; equitable benefit sharing; equitable distribution of rights and responsibilities; co-funding from government or projects; the level of annual income; and direct dependence of local livelihoods on mangroves. Protecting mangroves requires a policy shift in land-use planning to address the drivers of mangrove deforestation and degradation. Cross-sectoral coordination also needs to be further enhanced to improve effectiveness in law enforcement. Incentives designed by policies and projects should encourage local people to replant new mangrove forests, and also maintain and sustain newly planted mangroves and existing mangrove forests. Enhancing local participation in mangrove forest protection and development also requires accountable and transparent benefit-sharing and inclusive decision making. n

Presented during S8: Tropical wetlands and opportunities for climate change adaptation and mitigation – Scientific advancements and innovative tools II

P1: A GLOBAL TREATY FOR WETLANDS EXISTS SINCE 50 YEARS. WHAT’S IN IT FOR HUMANITY’S CURRENT CHALLENGES AND FOR SCIENTISTS?

Rojas Urrego, Martha, Convention on Wetlands 2021 marks the 50th anniversary of the adoption of the ‘Convention on Wetlands’ in the city of Ramsar, on 2 February 1971. The treaty covers all water-related ecosystems, from upstream glaciers and freshwater sources to coastal marine areas, including rivers and lakes, mangroves and peatlands, marshes and reefs. The 1960s marked a turning point, when early results of modern wetland research started to gain attention by policymakers and finally led to the adoption of the Convention. There was an initial focus on migratory waterbirds, useful biodiversity indicators and appreciated game. However, the Wetland Convention gradually developed and implemented its much broader wise use concept based on an ecosystem approach. The treaty is the legal framework for the conservation and wise use of wetlands by the 171 Contracting Parties to the Convention. To support this work, science-based tools are developed and awareness raised to show that wet ecosystems are among the most productive on earth, contributing to human livelihoods, acting as arteries and purifiers of freshwater, providing the most efficient carbon store and protecting us from floods, droughts and other disasters.

However, human draining and destruction of wet ecosystems is accelerating since the 19th century. We have not yet been able to slow it down: Current wetland loss is three times greater than that of forests. Despite this unfavourable evolution, the Convention provides today the most visible and respected global platform to raise awareness of wetland benefits. It develops management tools to safeguard wetlands and to include them in national development policies and plans, as a significant contribution to achieve the Sustainable Development Goals. The Convention appreciates the SWS’s contribution to the Convention processes through its consolidated understanding of wetland roles and functions, not only based on natural sciences, but also on economic valuation, social analysis and gender considerations. This is the place to share it with the 171 Contracting Parties, who have chosen the Convention on Wetlands as their global tool to promote wetland-based solutions, relying on sound scientific understanding and know-how. n

Presented during S8: Tropical wetlands and opportunities for climate change adaptation and mitigation – Scientific advancements and innovative tools II

P2: FROM RIVERS TO THE COASTS: ASSESSING WETLAND FUNCTIONS IN ALTERED LANDSCAPES IMPROVES ECOLOGICAL OUTCOMES

Berkowitz, Jacob, US Army Engineer Research and Development Center Johnson, David Berkowitz, Jacob Johnson, David Price, Jaybus Landscape-scale alterations impact the extent and function of wetlands in both riverine and coastal settings. For example, levees have disconnected the Mississippi River from up to 70% of its historic floodplain. The remaining constrained floodplain wetlands receive flood pulses that diverge from natural hydropatterns, and this effect will be exacerbated under anticipated climate change scenarios. The remaining floodplain wetlands provide a variety of ecological functions, although alteration has shifted the magnitude of functional outcomes. This represents a wetland functional tradeoff in which alterations can enhance some functions (typically those related to physical processes) while decreasing other functions (often associated with biologically mediated processes such as habitat maintenance). Hydrologically altered floodplain wetlands in backwater areas exemplify these ecological tradeoffs. Backwater wetlands experiencing prolonged inundation provide ideal conditions for denitrification, which improves water quality. Yet the same anaerobic conditions supporting

denitrification can induce aquatic habitat quality limitations due to hypoxia. Within a coastal restoration context, an analysis of >40-year-old dredged material beneficial use projects further highlights these functional tradeoffs. The restored wetlands are highly functional but remain distinct from unaltered reference areas. The analysis indicates that gains in physically derived functions (e.g., energy dissipation, water storage) yield benefits at faster timescales than biologically driven functions. However, increases in biological functions work to further enhance physical functions as restoration sites mature. For example, increases in vegetative structural complexity over time improves sediment retention efficiency. How we quantify and interpret these ecological functional tradeoffs across different landscapes is key to improving the valuation of wetlands, which in turn promotes conservation and restoration initiatives. Additionally, understanding how alteration changes wetland functions supports the deliberate optimization of ecological outcomes from river systems to the coast. n

Presented during S8: Tropical wetlands and opportunities for climate change adaptation and mitigation – Scientific advancements and innovative tools II

P3: PULSING DYNAMICS AND THE DEVELOPMENT OF COASTAL ECOSYSTEMS FACING SEA-LEVEL RISE

Gaiser, Evelyn, Florida International University Water flow pulses are a common denominator of flowingwater ecosystems and may play a particularly regulatory role in low-gradient coastal wetlands. Coastal wetlands receive pulses of freshwater from rainfall and frequently managed flows, while also being subject to marine water pulses from tides and tropical storms. Resultant water level fluctuations often lead to energy subsidies that stimulate production and consumption. These energy subsidies may be particularly important in coastal wetlands facing subsidence and collapse of peat soils driven by accelerating sea-level rise and saltwater intrusion. Where subsidy pulses accelerate sedimentation or soil development by plants and/or algal mats, they may allow coastal ecosystems to continue to develop carbon stores and associated functions and services. Pulses of connectivity allow mobile consumers to track and redistribute limiting resources in coastal wetlands. The Florida Coastal Everglades is exceptionally exposed and sensitive to pulses of fresh and marine water and associated resources. Two decades of long-term data provide examples of water pulses that: (1) increase production and inland movement of salt-adapted vegetation, (2) connect upstream and downstream food webs with long-term legacies in populations, and (3) increase the provisioning of critical ecosystem services that feed back to the freshwater pulse restoration process. We reflect on the theory of pulse dynamics and how coastal ecosystems may be maintained in states that develop critical organic carbon stores as sea-levels rise. For example, hurricanes in 2005 and 2017 that delivered 3-10 cm-thick phosphorusrich storm surge deposits to coastal mangrove forests. The inorganic deposit and resultant organic accretion by the recovering forest result in elevation gains, and important contributor to resilience to sea-level rise. At the same time, freshwater pulse restoration maintain plant and microbialmat driven accretion in upstream marshes. Results are interpreted in the context of other pulsed ecosystems confronted by multiple interacting drivers and legacies. n

Presented during S8: Tropical wetlands and opportunities for climate change adaptation and mitigation – Scientific advancements and innovative tools II

P4: THE LIMITS OF TIDAL WETLAND VERTICAL ADJUSTMENT TO SEA-LEVEL RISE: CAHOON, REED AND DAY REVISITED

Feedbacks between inundation, sedimentation and carbon sequestration allow a degree of vertical adjustment to sealevel rise in tidal mangroves and marshes that may extend over millennial timescales. From early in the Holocene, mangroves tracked sea-level rise at rates considerably higher than those encountered over the past century, and in doing so appear to have influenced global atmospheric greenhouse gas concentrations. However, paleo-stratigraphic studies in mangroves and tidal marshes have suggested that the upper limits of this vertical adjustment may be exceeded by rates of sea-level rise projected for the latter half of this century. The global Surface Elevation Table-Marker Horizon (SET-MH) network is providing important information on the processes at work in determining tidal wetland responses to sea-level rise. An analysis of more than a decade of tidal marsh SET-MH observations across four continents suggests that while accretion rates are generally keeping pace with sea-level rise, elevation gain is not. At higher rates of accretion marshes show lower incremental gain in elevation, the implication being that the weight of that new material enhances upper-level subsidence thereby compromising elevation gain. This process constrains the upper limits of tidal wetland vertical adjustment in most settings and reconciles short- and long-term observations of wetland response to high rates of sea-level rise. n