Showing papers in "Wetlands in 2019"

Typha (Cattail) Invasion in North American Wetlands: Biology, Regional Problems, Impacts, Ecosystem Services, and Management

Abstract: Typha is an iconic wetland plant found worldwide. Hybridization and anthropogenic disturbances have resulted in large increases in Typha abundance in wetland ecosystems throughout North America at a cost to native floral and faunal biodiversity. As demonstrated by three regional case studies, Typha is capable of rapidly colonizing habitats and forming monodominant vegetation stands due to traits such as robust size, rapid growth rate, and rhizomatic expansion. Increased nutrient inputs into wetlands and altered hydrologic regimes are among the principal anthropogenic drivers of Typha invasion. Typha is associated with a wide range of negative ecological impacts to wetland and agricultural systems, but also is linked with a variety of ecosystem services such as bioremediation and provisioning of biomass, as well as an assortment of traditional cultural uses. Numerous physical, chemical, and hydrologic control methods are used to manage invasive Typha, but results are inconsistent and multiple methods and repeated treatments often are required. While this review focuses on invasive Typha in North America, the literature cited comes from research on Typha and other invasive species from around the world. As such, many of the underlying concepts in this review are relevant to invasive species in other wetland ecosystems worldwide.

Climate Change Impacts on the Coastal Wetlands of Australia

Abstract: The Australian continent spans coastal wetland settings ranging from extensive mangrove forest and sabkha plains occupying in the tropical north, to the southern half of the continent, where high wave energy constrains wetlands within numerous barrier-fronted estuaries, drowned river valleys and coastal embayments. Only on the island of Tasmania are mangroves absent; elsewhere mangroves, Casuarina, Melaleuca and saltmarsh interact in ways illustrative of the effects of ongoing climate, tidal and sea-level change. Observations over several decades have suggested that recent anthropogenic climate change may already be impacting Australian coastal wetlands in important ways. A period of accelerating sea-level rise has been associated with saline intrusion, mangrove encroachment and Melaleuca dieback in the tropical north, punctuated by widespread mangrove mortality in drought periods. The consistent trend of mangrove encroachment and replacement of saltmarsh in the south, is associated with an “accretion deficit” in saltmarsh during contemporary sea-level rise. We review the ecological and cultural implications of these changes, including impacts on habitat provision for migratory birds, fisheries values, carbon sequestration and Indigenous cultural values. Current legislative and policy protections may not be sufficient to meet the increasingly dynamic impacts of climate change in altering wetland boundaries, composition and function.

The Second Warning to Humanity – Providing a Context for Wetland Management and Policy

Abstract: The Second Warning to Humanity provides a clarion call for wetland researchers and practitioners given the loss and degradation of wetlands, the declining availability of fresh water, and the likely consequences of climate change. A coordinated response and approach to policies has the potential to prevent further degradation and support resilient wetlands that can provide a range of ecosystem services, including buffering wetlands from climate impacts, and avoiding major climate amplification from temperature-induced release of additional carbon dioxide and methane while addressing the causes and consequences of global climate change. The Warning to Humanity also provides an opportunity for organisations such as the Society of Wetland Scientists to raise the profile of wetlands and to initiate a discussion on how to respond and change direction from the destructive development trajectory that led to wetland loss and degradation. It also provides a signal for a reappraisal of the effectiveness of the implementation of the Ramsar Convention on Wetlands as an international mechanism for ensuring the sustainability of wetlands.

Conservation of Wetlands and Other Coastal Ecosystems: a Commentary on their Value to Protect Biodiversity, Reduce Disaster Impacts, and Promote Human Health and Well-Being

Abstract: There is substantial, growing literature that details positive human health effects, psychological and physiological, of exposure to “nature,” including “green” and “blue space,” with evidence suggesting that diversity of species or environments may have specific positive human health benefits. These health benefits are important ecosystem services provided by healthy ecosystems. In this paper, we discuss several critical ecosystem services provided by wetlands including disaster risk reduction, with an emphasis on benefits to human health and well-being. Impacts to human health via damage to ecosystem services from disasters have rarely been considered in disaster planning or mitigation, nor have the health benefits been part of the framework for planning urban greenspaces and land-use. Coastal wetlands can be part of “natural and nature-based” solutions, minimizing the impacts of disasters by buffering coastal communities from storms and erosion and absorbing flood waters. In addition, mental and physical health benefits of experiencing healthy wetlands could offset some stress and disease encounters related to disasters. Thus, coastal wetlands should be part of a strategy for reducing the risk posed by disasters and facilitating recovery. We conclude with recommendations for research priorities and specific inclusion of wetlands in coastal community planning for disaster response and recovery.

A Classification System for Colombian Wetlands: An Essential Step Forward in Open Environmental Policy-Making

Abstract: Knowledge about the distribution and diversity of wetlands has become an essential tool for environmental management and policy-making. Yet, while recent estimates indicate that 27% of the area of Colombia is covered by wetlands and despite a number of regional studies, information about the diversity of wetlands nationally is scarce. In response, we present a national wetland classification system that is based on an ecological approach, from the perspective of wetland scientists, and which builds upon the assumptions underlying the flood pulse concept and hydrogeomorphic approach. Thus, the approach and structure of the Brazilian wetland classification system are used, with geomorphological adjustments made according to Colombia’s topography. The classification is hierarchical, multi-scale, functional, and organized according to four levels (system, macroregion, subsystem, and class), with the wetland diversity of Colombia represented nationally by 89 macrohabitats across marine-coastal, inland, and anthropogenic systems. The primary purpose of this classification is to provide integrated and organized information on the distribution and diversity of Colombian wetlands that will serve as a baseline for transparent environmental policy-making.

Assessing Changes of Habitat Quality for Shorebirds in Stopover Sites: a Case Study in Yellow River Delta, China

Abstract: The population of shorebirds in the East Asian–Australasian Flyway (EAAF) has severely declined over the past several decades. One reason for this condition is low survival in stopover sites in the Yellow Sea Ecoregion (YSE) due to habitat degradation. Here, we focused on shorebird habitat quality in the Yellow River Delta (YRD), which is a representative shorebird stopover site in the YSE on the EAAF. We used the InVEST model to assess the past and future shorebird habitat quality changes by considering the effects of anthropogenic threats. The entire duration of the study was 1999–2016, and the modeling was done on 2000 and 2015 data. Our results indicate that the abundance of 11 shorebird species had significant downward trends (70–97% reduction) during 1999–2015. Tidal flats in the nature reserve had higher habitat quality than that in the northwestern (NW) and eastern (E) parts of the YRD because major mariculture occurred in NW and E. The mean habitat qualities in NW and E decreased by 27 and 31% during 2000–2015, respectively. The optimal habitat in the YRD declined from 1433 km2 in 2000 to 1154 km2 in 2015. The habitat quality decreased significantly in E and Dongying Port parts during 2015–2020.

Moving from generalisations to specificity about mangrove-saltmarsh dynamics

Abstract: Spatial and temporal variability in factors influencing mangrove establishment and survival affects the distribution of mangrove, particularly near their latitudinal limit, where mangrove expansion into saltmarsh is conspicuous. In this paper the spatial variability in mangrove distribution and variability in factors influencing mangrove establishment and survival during the Quaternary period are reviewed, focussing on research at latitudinal limits in Australia and mainland USA. Despite similarities in the response of mangrove to some drivers, the expression of these drivers is both spatially and temporally variable, demonstrating the need for analyses of mangrove-saltmarsh dynamics to move beyond generalisations and incorporate regional and local-scale specificity. We propose i) that precursory recognition that ‘correlation does not mean causation’ is inadequate and assumptions, caveats, and limitations should be clearly articulated in correlative studies; ii) experimental design in manipulative experiments must also articulate the spatial and temporal scale to which the analysis is relevant; and iii) analyses that draw from a range of methods will provide greater confidence. Integrated research programs that transect spatial and temporal scales and incorporate a range of techniques are essential to improve projections. Mangrove-saltmarsh distribution research should move beyond simple models that assume equilibrium between realised and fundamental niches.

Vegetation Response to Hydrological Changes in Poyang Lake, China

Abstract: Poyang Lake is the largest freshwater lake and area of alluvial wetlands in China. The vast, seasonally-inundated alluvial plain is internationally recognized for its rare and endangered species which was one of the first to be included in The Ramsar Convention’s List of Wetlands of International Importance. Average lake stage (water level) has declined during both the summer wet season and dryer part of the year since the early 2000s, resulting in significant hydrological and ecological consequences. The purpose of this study is to describe changing spatial patterns for major vegetation types and relate vegetation response to changing hydrological conditions. The results suggest that vegetation patterns have shifted substantially in recent years. Most significant is spread of reed and sedge dominated plant communities to sites 1 m to 2 m lower in elevation. Reed communities that continue to dominate the highest elevations within the lake basin expanded across shallow regions of the lake previously too wet for regeneration. In contrast, sedges cannot tolerate dry conditions, and therefore, declined on higher sites. The dominance of aquatic plant communities doubled in area at low elevation sites in the absence of the severe floods that normally inhibit regeneration. We attributed the variation of vegetation patterns to the great water regime changes. However, lower lake stage has not resulted in a highly-degraded wetland ecosystem. Plant communities will continue to adjust to future long-term changes in lake hydrological conditions. The findings provide an important baseline in monitoring vegetation communities’ shifts in Poyang Lake wetland from which future research can be compared but also for other international tropical wetlands also impacted by similar threats.

Spatiotemporal Change of Vegetation Coverage and its Relationship with Climate Change in Freshwater Marshes of Northeast China

Abstract: Based on the normalized difference vegetation index and climate data, this study investigated the spatiotemporal change of fractional vegetation cover (FVC) and its relationship with climate change in freshwater marshes of Northeast China from 2000 to 2016 Although freshwater marshes in Northeast China have undergone loss during the past nearly 20 years, the FVC of unchanged marshes has increased by 034% per year over the study area, with the largest increases in Songnen Plain Correlation analysis results showed that warm growing season temperatures could enhance the FVC of marshes in the Greater and Lesser Khingan Mountains, but reduce the FVC in arid and semi-arid grassland regions of Songnen Plain and Eastern Inner Mongolia By contrast, the increased growing season precipitation could significantly enhance the FVC of marshes in semi-arid grassland regions of Northeast China, but reduce the FVC of marshes in the Lesser Khingan Mountains and Sanjiang Plain Under the background of future climate change, we can predict lower FVC of marshes in Songnen Plain and Eastern Inner Mongolia, but higher FVC of marshes in the Changbai Mountains in the future This research is expected to provide valuable implications for the protection and restoration of wetland vegetation in Northeast China

Urban Wetland Planning and Management in Ghana: a Disappointing Implementation

Abstract: The Greater Accra Metropolitan Area (GAMA), in Ghana, has witnessed the destruction of approximately 60% of its wetlands. Wetlands provide many valuable ecological, social, economic, and recreational functions. Appreciation of the importance of wetlands has increased in recent years, consequently, wetland protection has been recognized globally through international agreements, as well as through national, regional, and local policies and regulations. Empirical studies on wetland destruction in urbanized Ghana are limited. Adopting a qualitative approach, this research examines the causes and extent of wetland destruction in the GAMA. The study reveals that measures designed and implemented to protect wetlands in the GAMA have proved ineffective due to non-implementation and monitoring of wetland protection strategies, policies and projects. These shortcomings reflect a lack of resources and participation of stakeholders in the planning, development and implementation of wetland protection policies. The study concludes with a recommendation for more direct participation of stakeholders in developing and implementing plans and strategies to manage wetlands in Ghana.

Fine-Scale Mapping of Coastal Plant Communities in the Northeastern USA

Abstract: Salt marshes of the northeastern United States are dynamic landscapes where the tidal flooding regime creates patterns of plant zonation based on differences in elevation, salinity, and local hydrology. These patterns of zonation can change quickly due to both natural and anthropogenic stressors, making tidal marshes vulnerable to degradation and loss. We compared several remote sensing techniques to develop a tool that accurately maps high- and low-marsh zonation to use in management and conservation planning for this ecosystem in the northeast USA. We found that random forests (RF) outperformed other classifier tools when applied to the most recent National Agricultural Imagery Program (NAIP) imagery, NAIP derivatives, and elevation data between coastal Maine and Virginia, USA. We then used RF methods to classify plant zonation within a 500-m buffer around coastal marsh delineated in the National Wetland Inventory. We found mean classification accuracies of 94% for high marsh, 76% for low marsh zones, and 90% overall map accuracy. The detailed output is a 3-m resolution continuous map of tidal marsh vegetation communities and cover classes that can be used in habitat modeling of marsh-obligate species or to monitor changes in marsh plant communities over time.

Distribution and Long-Term Population Trends of Wintering Waterbirds in Poyang Lake, China

Abstract: Although total wintering waterbirds have increased in Poyang Lake, some groups or species might have declined. Identifying declining groups and species will help to optimize conservation strategies. In addition, knowledge of waterbird distribution is required to identify priority areas for protection. In this study, we aimed to explore long-term population trends of waterbird groups and species and to investigate waterbird distribution in Poyang Lake by integrating survey data from 1996/1997 to 2014/2015. Poyang Lake Nature Reserve, Duchang and Nanji Wetland Nature Reserve had high waterbird richness and abundance and high proportion of IUCN endangered species, thus they are important areas for waterbird protection. An important limitation to waterbird protection in the three areas is lack of management rights of most sub-lakes. Most waterbird groups in Poyang Lake have grown, but ducks have declined. Hunting and the decline of aquatic vegetation might be driving the duck declines. In addition, White-naped Crane (Grus vipio), Spot-billed Duck (Anas poecilorhyncha) and Northern Lapwing (Vanellus vanellus) have declined. While we believe the data presented here indicate general trends in groups and species, the analyses suffered from variation in methods used in different surveys. We advocate long-term waterbird monitoring using standardized methods to better understand waterbirds’ population dynamics.

Sea-Level Rise and Climate Change Impacts on an Urbanized Pacific Coast Estuary

Abstract: The San Francisco Bay-Delta estuary, the largest estuary on the west coast of North America, has lost over 90% of its tidal wetlands through conversion to agriculture, grazing or urban development. Accelerated sea-level rise poses an additional threat to the remaining wetlands, and keeping pace requires that they increase in relative elevation through trapping of suspended sediment or increasing organic productivity in the root zone. Suspended sediment concentrations (SSC) have been declining in rivers and deep channels, and although little is known about sediment dynamics in shallow areas, sediment supply to tidal wetlands may not be sufficient to maintain their elevations in the future. Wetlands will be constrained by existing development and mountainous terrain. Increases in tidal wetland salinity have been occurring in saline, brackish and the western edges of freshwater tidal wetlands. To mitigate for sea-level rise, considerable acreages currently are being restored, with and without active management practices. Restoration techniques are being piloted to increase shoreline protection, resiliency, and high tide refuge in adaptation to current and projected sea level rise. We recommend additional research into plant physiological responses to combinations of climate change impacts, as well as suggest potential practical policy positions.

Blue Carbon: an Additional Driver for Restoring and Preserving Ecological Services of Coastal Wetlands in Tampa Bay (Florida, USA)

Abstract: Coastal habitats, including mangroves, salt marsh, and seagrass meadows, provide numerous ecosystem services, including improved water quality, shoreline stabilization, and essential fish habitat. Over the past few decades, the quantification of greenhouse gas fluxes in wetlands has improved, leading to the recognition of these habitats as long-term carbon sinks. Quantifying this “blue carbon” as an ecosystem service provides added value for wetland protection and restoration and serves as a useful management tool when implementing plans for sustained ecosystem health and productivity. Tampa Bay (Florida, USA), a highly urbanized estuary, provides an interesting case study to assess the role of blue carbon in supporting management and informing restoration decisions. This review provides results from the Tampa Bay Blue Carbon Assessment, which quantified existing carbon stocks and identified the future carbon sequestration trajectories of coastal habitats with respect to climate change and sea-level rise. Examples are provided of how these data can be used to prioritize restoration efforts, support and enhance management decisions, and potentially attract new partners to support wetland restoration projects that offer additional climate change mitigation and adaptation benefits. This added valuation can help drive investment towards additional wetland restoration activities to help meet management targets in estuaries worldwide.

Mapping Mountain Peatlands and Wet Meadows Using Multi-Date, Multi-Sensor Remote Sensing in the Cordillera Blanca, Peru

Abstract: Wetlands (called bofedales in the Andes of Peru) are abundant and important components of many mountain ecosystems across the globe. They provide many benefits including water storage, high quality habitat, pasture, nutrient sinks and transformations, and carbon storage. The remote and rugged setting of mountain wetlands creates challenges for mapping, typically leading to misclassification and underestimates of wetland extent. We used multi-date, multi-sensor radar and optical imagery (Landsat TM/PALSAR/RADARSAT-1/SRTM DEM-TPI) combined with ground truthing for mapping wetlands in Huascaran National Park, Peru. We mapped bofedales into major wetland types: 1) cushion plant peatlands, 2) cushion plant wet meadows, and 3) graminoid wet meadows with an overall accuracy of 92%. A fourth wetland type was found (graminoid peatlands) but was too rare to map accurately, thus it was combined with cushion peatland to form a single peatland class. Total wetland area mapped in the National Park is 38,444 ha, which is 11% of the park area. Peatlands were the most abundant wetland type occupying 6.3% of the park, followed by graminoid wet meadows (3.5%) and cushion wet meadows (1.3%). These maps will serve as the foundation for improved management, including restoration, and estimates of landscape carbon stocks.

Drivers and Changes of the Poyang Lake Wetland Ecosystem

Abstract: This paper serves as both a review of the latest science on the Poyang Lake wetland ecosystem and as an introduction to this Special Issue guest-edited by Jun Xu. Poyang Lake is the largest freshwater lake in China and one of the largest freshwater lake/wetland complexes in Asia. Poyang Lake’s associated floodplain wetlands play a critical role for regional and global biodiversity conservation, particularly wintering migratory birds. Since the Three Gorges Dam became operative in 2003, the magnitude and frequency of extreme seasonal water-level fluctuations in Poyang Lake have increased significantly. We review the existing literature and contributions to this Special Issue on the Poyang Lake wetland ecosystem and their biota in relation to impacts from the Three Gorges Dam. Resulting impacts on, and adaptations of, Poyang Lake biota to the hydrological changes caused by operation of the dam are poorly understood. Adaptive management of this lake and its associated wetlands needs to be further assessed through comprehensive, long-term monitoring covering a wide range of parameters related to the system’s hydrological characteristics, water quality, geomorphology, aquatic biota, wetland vegetation, and associated wetland fauna.

Microtopography Alters Hydrology, Phenol Oxidase Activity and Nutrient Availability in Organic Soils of a Coastal Freshwater Forested Wetland

Abstract: Hummock-hollow microtopography is a unique feature of wetland ecosystems, but our understanding of its effects on soil carbon and nutrient cycling is limited. We investigated effects of microtopography on hydrology, phenol oxidase activity (POX) and nutrient availability in a freshwater forested wetland of coastal North Carolina. Water table depth (WTD) was measured from September 2012 to August 2013. Ion exchange probes were used to measure nutrient concentrations prior to soil sample collection in August 2013. WTD fluctuated seasonally with maximum and minimum WTD resulting in 92% (September 2012) to 8% (June 2013) of the site in flooded and non-flooded conditions, respectively. Hummocks had greater POX activity (12 ± 2.8 μmol g−1 h−1) compared to hollows (4 ± 0.7 μmol g−1 h−1) and greater concentrations of potassium and sulfur, but lower concentrations of calcium, iron, zinc, boron, and lead. POX was negatively correlated with soil water content. Higher enzyme activity in hummocks likely drives greater rates of carbon and nutrient cycling compared to hollows, consistent with observations that hummocks are hotspots for CO2 fluxes. Microtopography altered site-level hydrologic conditions, phenol oxidase activity and nutrient availability with important implications for understanding carbon and nutrient cycling in forested wetlands and response to changes in hydrology.

Speciation and Spatial Distribution of Heavy Metals (cu and Zn) in Wetland Soils of Poyang Lake (China) in Wet Seasons

Abstract: The distribution of heavy metals (Cu and Zn) and their geochemical speciation (exchangeable fraction, carbonate fraction, Fe/Mn oxide fraction, organic fraction and residual fraction) in wetland soils of Poyang Lake were examined by modified Tessier sequential extraction methods. The results showed that the Cu and Zn concentrations in the wetland soils were 6.83–342.54 mg·kg−1 and 34.39–195.36 mg·kg−1, respectively. The highest heavy metal concentrations were found in the wetland soils located in the lower reaches of mines and metal smelters. The metal speciation analysis showed that Cu and Zn were mainly linked to the residual fraction in all samples which account for 65.64% and 68.14%, respectively. The content of the exchangeable fraction (Cu 1.00%, Zn 3.60%) and carbonate fraction (Cu 2.09%, Zn 1.53%) was generally lower. Assessments of pollution levels revealed that Cu and Zn were much higher than their background value and heavy metal pollution in the wetland soils located in the lower reaches of mines and metal smelters was often more severe. The sites Duchang and Hukou were least polluted by Cu and Zn.

Relationship Between Vegetation Community Distribution Patterns and Environmental Factors in Typical Wetlands of Poyang Lake, China

Abstract: Poyang lake is the largest freshwater lake in China, possessing global ecological functions. Impact of soil characteristics on vegetation distribution is potentially important but is poorly understood in this typical vast water-passing lake wetland. To explore the relationships between soil properties and vegetation distribution, soil moisture, soil nutrients, species construction, diversity and biomass were measured monthly in two dominant vegetation communities, namely, the Artemisia selengensis community and the Carex cinerascens community. Canonical correspondence analysis (CCA) and spearmen correlation were performed to evaluate the relationships between vegetation characteristics and edaphic variables. Results showed great heterogeneity in the ecological characteristics of plants. There are positive relationships between soil nutrients and ecological characteristics of plants, especially the biomass and the maximum height of the dominant species. Cynodon dactylon and Artemisia selengensis were mainly distributed in the upland with lower nutrient concentration and moisture content, whereas Cardamine lyrate, Triarrhena Lutarioriparia and Carex cinerascens were mainly found near the lake shore where the moisture and nutrients accumulated, demonstrating a legible zonal distribution along the edaphic gradient. The findings have provided an extension to the existing literatures, improving the understanding of the potentially crucial edaphic effects on vegetation in Poyang lake wetlands.

Linking Wetland Ecosystem Services to Vector-borne Disease: Dengue Fever in the San Juan Bay Estuary, Puerto Rico

Abstract: Mosquito-borne diseases are an increasingly important health concern, which pose great challenges for safe and sustainable control and eradication. This reality calls for management approaches that consider multiple aspects of the transmission cycle from a landscape and vector ecology perspective, to socio-economic elements that may increase exposure. This study seeks to better understand these pathways using dengue fever in the San Juan Bay Estuary (SJBE), Puerto Rico. Dengue is transmitted by Aedes aegypti, a species that thrives in cities. Here we ask which elements within the urban landscape could be managed to help prevent dengue outbreaks. We studied the potential of coastal wetlands in the SJBE to buffer vector proliferation, hypothesizing that wetland ecosystem services lead to lower dengue occurrence. We test this hypothesis using census-block level dengue data from 2010-13, including the largest epidemic in Puerto Rican history. Our analytical model includes socio-economic factors and environmental controls that may also affect dengue dynamics. Results from beta-binomial regressions and model averaging indicated that dengue occurrence was lower in neighborhoods with higher wetland cover even after controlling for population density and other socio-economic aspects. Our models suggest that heat hazard mitigation is partly responsible for the association between wetlands and dengue.

Modeled Sediment Availability, Deposition, and Decadal Land Change in Coastal Louisiana Marshes under Future Relative Sea Level Rise Scenarios

Abstract: The ability, or lack thereof, for wetlands in coastal Louisiana to maintain elevation capital has been well documented in the literature to be a function of local and regional factors as well as environmental conditions. The Integrated Compartment Model (ICM) framework developed for the state of Louisiana’s Coastal Master Plan models hydrologic, vegetation, and wetland elevation dynamics and captures regional and local dynamics of wetland elevation, inundation and sedimentation processes. It provides insights into the relative sensitivities of wetland evolution to environmental drivers under uncertain future environmental conditions. A systematic, and computationally efficient modeling exercise was conducted to test coastal marsh survival across a wide range of possible future relative sea level rise rate scenarios. Model results indicate a diverse response with respect to sediment deposition and marsh survival driven by regional subsidence rates and proximity to suspended sediment sources. Sediment poor regions of coastal Louisiana are particularly sensitive to relative sea level rise under all but the most optimistic of future sea level rise rates simulated. Coastal marshes with high sediment availability fare much better under most scenarios tested, despite high rates of relative sea level rise.

Landscape-Level Consequences of Rising Sea-Level on Coastal Wetlands: Saltwater Intrusion Drives Displacement and Mortality in the Twenty-First Century

Abstract: Coastal wetlands are shrinking rapidly due to land-use activities. Accelerated sea-level rise (SLR) associated to the warming climate is also affecting coastal wetlands, particularly in islands with limited coastal plains. We analyzed coastal wetland changes in Puerto Rico by applying the Sea Level Affecting Marshes Model under two scenarios by 2100. We also analyzed mortality and recruitment in a freshwater swamp dominated by the tree Pterocarpus officinalis Jacq. in the context of landscape saltwater-intrusion and drought. Our results indicate mangroves and estuarine water would replace the areas currently covered by other saltwater and freshwater wetlands, and saltmarsh would encounter the most relative loss among wetland types. A moderate SLR of 1 m by 2100 allows expansion of mangroves but would decrease saltmarsh and freshwater wetlands. A 2-m SLR would decrease the distributions of all vegetated wetlands, mostly replaced by estuarine water. In the P. officinalis forest, saltwater-intrusion and drought increased tree mortality during 2003–2015 compared to 1994–2003. Saltwater intrusion had a more significant negative effect on tree recruitment than on mortality in this Pterocarpus forest. Coastal wetlands are facing challenges to their persistence at current locations due to accelerated SLR, limited coastal lands, and a modified hydrological regime.

Fine Root Traits Are Correlated with Flooding Duration while Aboveground Traits Are Related to Grazing in an Ephemeral Wetland

Abstract: Functional traits affect species ranges, but it is unclear how above and below-ground traits determine species responses to flooding and herbivory in wetland communities. We analyzed community-weighted means (CWM) of nine functional traits along a hydrological gradient inside and outside of grazing exclosures in an ephemeral wetland in New Zealand. Root traits exhibited the strongest relationships with the flooding gradient. Root aerenchyma increased linearly as flooding increased but plateaued in the ungrazed treatment. Root dry matter content and root tissue density decreased non-linearly as flooding increased. Grazing reduced the strength of the trait-flooding relationships for all traits except root tissue density, specific root length, and aboveground dry matter content. Specific leaf area decreased non-linearly and height increased linearly with flooding in the ungrazed treatment. Our results indicate that fine root traits can provide more information about the functional adaptation of plants to variation in flooding duration than aboveground traits, but traits such as height and specific leaf area responded to the exclusion of herbivores. Altered hydrological dynamics driven by changes in precipitation regimes will induce shifts in species ranges. Fine root traits, especially aerenchyma, can be used to predict how wetland species will respond to changes in soil hydrology.

Rapid Increases in Bat Activity and Diversity after Wetland Construction in an Urban Ecosystem

Abstract: Wetland construction can mitigate the biodiversity and water quality losses associated with reduced natural wetland coverage. While beneficial effects of wetland construction for bats have been observed in natural and rural settings, the effects of wetland construction on bats in an urban ecosystem are less understood. We used passive acoustic monitoring to measure bat activity levels and diversity at two constructed wetlands and two control sites on the University of North Carolina Greensboro campus, in Greensboro, North Carolina, USA. We monitored all 4 sites before and after wetland construction. Pre-wetland construction, there were few differences in bat activity and community structure at our sites. After wetland construction, we observed greater activity, attributable to all species we recorded, at wetland sites compared to control sites. Species diversity and species richness were also higher at wetland sites compared to control sites. When comparing the same sites before and after wetland construction, both bat activity and species richness increased after construction, but the effects were seen in Winter and not Spring. Our results demonstrate that bats use constructed wetlands in urban ecosystems similarly to other habitat settings. Increases in bat activity, diversity, and species richness occurred within one year of wetland construction.

Habitat Traits Associated with Mosquito Risk and Aquatic Diversity in Urban Wetlands

Abstract: Urban wetlands are increasingly being used to manage stormwater, provide valuable resources for biodiversity, and to improve public amenity and wellbeing. However, community concern regarding an increase in the abundance of mosquitoes that pose risks to public health can severely undermine support for these habitats. Our limited understanding of relationships between wetlands, aquatic biodiversity, and mosquitoes in urban areas exacerbates this fear and inhibits our ability to assess potential risks and manage existing conflicts. We sampled adult mosquitoes and aquatic macroinvertebrates at 23 wetlands across the greater Sydney region, Australia. We analysed relationships between macroinvertebrates and mosquito abundance, and examined links with habitat, wetland design and surrounding land use. The mosquito assemblage as a whole showed no links with macroinvertebrate diversity or wetland design, but there were relationships between these variables and individual mosquito species. The diversity of aquatic macroinvertebrates was correlated with surrounding land use and wetland design rather than available aquatic habitat. When assessing mosquito risk, mosquitoes should not be considered collectively as that does not reveal links with urban wetland habitats or measures of aquatic diversity. Instead, strategic species-specific responses should be implemented to create urban wetlands that maximise multiple values without posing threats to public health.

Procedure for Organic Matter Removal from Peat Samples for XRD Mineral Analysis

Abstract: Ombrotrophic peatlands are recognized archives of past atmospheric mineral dust deposition. Net dust deposition rates, grain size, mineral hosts and source areas are typically inferred from down-co ...

Influence of Inundation and Suspended-Sediment Concentrations on Spatiotemporal Sedimentation Patterns in a Tidal Freshwater Marsh

Abstract: Long-term marsh sustainability is threatened by environmental changes, especially accelerated rates of sea-level rise (SLR) and changing fluvial sediment supplies. Although direct observations of long-term marsh responses to these changes are challenging, this study examines shorter-term responses via bimonthly sedimentation measurements over 5 years in Dyke Marsh Preserve (DMP), a tidal freshwater marsh in the Potomac River (Chesapeake Bay tributary, USA). Observed patterns are evaluated with physical drivers (winds, river discharge, water-level changes, suspended-sediment concentrations (SSC)) that influence spatiotemporal variability within the marsh. Linear regression models reveal that water-level changes exert more influence on this variability than SSC in a system with plentiful sediment supply. Sedimentation rates increase linearly with inundation time, but a quadratic regression model explains more of the variability, especially for the inorganic fraction of sediment. This result indicates that fluvial sediment supply is key for marsh accretion and suggests an optimal response of sedimentation to increased inundation that non-linearly affects marsh vulnerability to future SLR. Ultimately, the SSC in adjacent waters is not available to nourish the marsh unless it is transported and retained on the platform. Self-sustaining feedbacks among inundation, sedimentation, elevation, and plants likely aid in maintaining equilibrium elevations over time and thus also marsh sustainability.

Does Proximity to Wetlands Matter? A Landscape-Level Analysis of the Influence of Local Wetlands on the Public’s Concern for Ecosystem Services and Conservation Involvement

Abstract: Understanding public perceptions can enhance the success of landscape-level conservation by helping recognize how to gather public support. However, perceptions of wetlands’ importance may differ based on proximity to a wetland. This study used a mail-out survey across the entire U.S. (n = 1030) to investigate the public’s knowledge of local wetlands, visitation to wetlands, concern over losing ecosystem services provided by wetlands, and involvement in wetlands conservation. Regression models were run to explore the impact of proximity to the nearest wetland on wetlands visitation, concern, and conservation involvement. Additionally, sociodemographics and outdoor recreation participation were tested as predictors. While proximity to wetlands did impact knowledge of wetlands in the local area and wetlands visitation, it was not directly a significant predictor of concern for wetlands ecosystem services or conservation involvement. However, wetlands visitation did increase concern for ecosystem services and conservation involvement. Furthermore, participation in birdwatching, wildlife viewing, and fishing were correlated with higher concern for ecosystems services provided by wetlands and involvement in wetlands/waterfowl conservation. Results suggest that fostering awareness of wetlands, encouraging visitation, and promoting non-consumptive outdoor recreation opportunities may increase support for wetlands regardless of individuals’ proximity to wetlands.

Management Strategies for the Conservation, Restoration and Utilization of Mangroves in Southeastern Mexico

Abstract: Mangrove forests in Tabasco, Mexico, require the conservation, utilization and rehabilitation of degraded areas. To determine their use potential, a regionalization was performed on the basis of edaphic conditions, geographic distribution, land use, natural protected areas and forest utilization. Additionally, the zoning of soils was performed by means of photointerpretation of geoforms in 1:20000 orthophoto maps for the location and analysis of 16 soil profiles and the analysis of hydrocarbon contamination in 20 sites. Furthermore, a dasometric inventory of 30 transects was performed. The mangrove area was determined with a supervised classification of 2009 SPOT 5 satellite images. Mangroves occupied 41,498.5 ha of Solonchak and Histosol soils. Mangroves contained up to 1184 trees ha−1 and had a maximum average height of 19 m. Regionalization determined that 55.0% of mangroves require protection, 5.8% correspond to an area polluted by heavy hydrocarbons and require restoration, and 39.2% require utilization by inhabitants.

Control of Non-migrating Bar Morphodynamics on Survival of Populus nigra Seedlings during Floods

Abstract: Populus nigra seedling survival to flood stresses during their first stage of development was analyzed in the Loire River, France. We related bar dynamics (assessed from bathymetrical, topographical, flow velocity, scour chains, and sediment grain size surveys) to seedling survival. The study highlights (i) the influence of flood succession and flood stages on seedling survival after establishment, (ii) the spatial distribution of fluvial processes at the bar scale and their relative contribution to seedling mortality, (iii) threshold values for each process. At the bar scale, 28% of mortality is explained by uprooting associated with erosion of sediments. To a lesser extent, uprooting by drag force applied on the stems and burying by sediments also contribute to seedling mortality. The majority of seedling mortality is ultimately due to a combination of erosion and burial (50.6%) during flood events. The relative contribution of each process depends on the combination and phasing of erosion and deposition processes, sediment supply (quantity and grain size), and flow velocity governed by hydrological variations. Based on the results of this study we hypothesize that the survival of seedlings during floods may be a function of local processes involved in bar dynamics.