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Highlights • Hurricane Wilma (2005) did not impact mangrove forest structure or stem productivity. • There was a negative relationship between leaf NPP and foliar residence time. • This relationship is a good proxy of canopy recovery for global mangrove NPP studies. Abstract Mangrove wetlands along coastal regions in neotropical northern latitudes are exposed to frequent hurricanes and therefore depend on resistant and resilient attributes to persist after these extreme events. However, few long-term studies have documented mangrove forest dynamics following hurricane disturbance to determine how species-specific phenotypic plasticity, species range shifts, and environmental stress interact to determine recovery trajectories. We present here a comprehensive analysis of Hurricane Wilma's (hereafter, "Wilma") impact (category 3, October 2005) on mangrove forest demography and aboveground net productivity in the Everglades, Florida (USA). We determined spatiotemporal patterns over a 15-year period (5 pre- and 10 post-Wilma) in three impacted sites on a productivity gradient along the Shark River Estuary. Hurricane resistance was evident in the low cumulative tree mortality and long-term recovery from defoliation (∼10 years). Aboveground standing carbon stocks were not significantly reduced, as mortality ranged only from 3 to 10%. A negative linear relationship between Leaf Net Primary Productivity (NPP L) and foliar residence time along the estuary shows that an increase in foliar production results in shorter residence time, which is defined by the interannual variation in NPP L rates and recovery periods across sites. We propose this relationship as a proxy of canopy recovery in latitudinal comparative studies across mangrove ecotypes and coastal settings. This work advances ecological disturbance theory and ecological modeling of mangrove forests; specifically, we provide quantitative relationships among structural properties and dynamic processes to validate agent-based demographic and biogeochemical models to forecast the impact of natural and human disturbances on mangrove wetlands under climate change. [ABSTRACT FROM AUTHOR]

We evaluated mangrove forest resilience in the Florida Coastal Everglades (FCE) by analyzing long-term (2001–2014) spatial and temporal patterns of litterfall net primary productivity (NPP L ), including the impact and recovery from two natural disturbance events: Hurricane Wilma (October-2005) and a cold snap (January-2010). Specifically, we tested whether the disturbance driven recovery trajectory of mangrove forests (i.e. recovery duration and rate) depends on the disturbance impact magnitude and initial forest structure in three study sites. Hurricane Wilma caused canopy defoliation at all sites and was a function of the wind-field strength such that higher wind speeds at the SRS-6 site (30–40 m s −1 ) induced greatest defoliation (4.7 Mg C ha −1 yr −1 ). Disturbance magnitude (decrease in NPP L from 2005 to 2006) was higher in SRS-6 (7.8 Mg C ha −1 yr −1 ), followed by SRS-4 (5.7 Mg C ha −1 yr −1 ) and SRS-5 (5.5 Mg C ha −1 yr −1 ). We observed differential NPP L recovery times among sites and species, where sites SRS-5 and SRS-6 returned to pre-Wilma NPP L rates by 2010 while SRS-4 has not yet fully recovered. In contrast, the cold snap had significant disturbance impact, yet recovery occurred within one month across all sites. We conclude that differential resilience to Hurricane Wilma was a result of a synergy of local changes in hydrology, salinity and storm impact. The long-term ability of subtropical mangroves to recover to pre-disturbance production rates within a short period (<5 years) demonstrates their resilience capacity in cases where massive defoliation occurs as result of natural disturbances. [ABSTRACT FROM AUTHOR]

Old growth mangroves in existing protected areas store more carbon than restored forests or plantations. Carbon storage in such forests has economic value independent of additionality, offering opportunities for policy makers to ensure their maintenance, and inclusion in climate change mitigation strategies. Mangrove forests of the Everglades National Park (ENP), South Florida, though protected, face external stressors such as hydrological alterations because of flooding control structures and agriculture impacts and saltwater intrusion as a result of increasing sea level rise. Moreover, decreased funding of Everglades’ restoration activities following the recent economic crisis (beginning 2008) threatens the restoration of the Greater Everglades including mangrove dominated coastal regions. We evaluate several economic and ecological challenges confronting the economic valuation of total (vegetation plus soil) organic carbon (TOC) storage in the ENP mangroves. Estimated TOC storage for this forested wetland ranges from 70 to 537 Mg C/ha and is higher than values reported for tropical, boreal, and temperate forests. We calculate the average abatement cost of C specific for ENP mangroves to value the TOC from $2–$3.4 billion; estimated unit area values are $13,859/ha–$23,728/ha. The valuation of the stored/legacy carbon is based on the: 1) ecogeomorphic attributes, 2) regional socio-economic milieu, and 3) status of the ENP mangroves as a protected area. The assessment of C storage estimates and its economic value can change public perception about how this regulating ecosystem service of ENP mangrove wetlands (144,447 ha) supports human well-being and numerous economic activities. This perception, in turn, can contribute to future policy changes such that the ENP mangroves, the largest mangrove area in the continental USA, can be included as a potential alternative in climate change mitigation strategies. [ABSTRACT FROM AUTHOR]

Highlights: [•] We study patterns of biomass and total NPP of mangrove ecotypes in the Everglades. [•] Vegetation patterns of mangroves represent the outcome of environmental gradients. [•] Riverine mangroves allocate most of the total NPP to aboveground (69%). [•] Scrub mangroves show the highest biomass allocation and production to belowground. [•] Production to biomass ratios were lower in riverine relative to scrub mangroves. [ABSTRACT FROM AUTHOR]

Abstract: Mangrove forests are found within the intertropical zone and are one of the most biodiverse and productive wetlands on Earth. We focus on the Ciénaga Grande de Santa Marta (CGSM) in Colombia, the largest coastal lagoon–delta ecosystem in the Caribbean area with an extension of 1280 km2, where one of the largest mangrove rehabilitation projects in Latin America is currently underway. Extensive man-made hydrological modifications in the region caused hypersaline soil (>90 g kg−1) conditions since the 1960s triggering a large dieback of mangrove wetlands (~247 km2). In this paper, we describe a new systematic methodology to measure mangrove height and aboveground biomass by remote sensing. The method is based on SRTM (Shuttle Radar Topography Mission) elevation data, ICEsat/GLAS waveforms (Ice, Cloud, and Land Elevation Satellite/Geoscience Laser Altimeter System) and field data. Since the locations of the ICEsat and field datasets do not coincide, they are used independently to calibrate SRTM elevation and produce a map of mangrove canopy height. We compared height estimation methods based on waveform centroids and the canopy height profile (CHP). Linear relationships between ICEsat height estimates and SRTM elevation were derived. We found the centroid of the canopy waveform contribution (CWC) to be the best height estimator. The field data was used to estimate a SRTM canopy height bias (−1.3 m) and estimation error (rms=1.9 m). The relationship was applied to the SRTM elevation data to produce a mangrove canopy height map. Finally, we used field data and published allometric equations to derive an empirical relationship between canopy height and biomass. This relationship was used to scale the mangrove height map and estimate aboveground biomass distribution for the entire CGSM. The mean mangrove canopy height in CGSM is 7.7 m and most of the biomass is concentrated in forests around 9 m in height. Our biomass maps will enable estimation of regeneration rates of mangrove forests under hydrological rehabilitation at large spatial scales over the next decades. They will also be used to assess how highly disturbed mangrove forests respond to increasing sea level rise under current global climate change scenarios. [Copyright &y& Elsevier]

• A mass balance-based hydrological model was modified to simulate soil porewater salinity in riverine mangrove forests. • The seasonal and annual interaction between freshwater inflow and sea level rise controls soil porewater salinity values in Everglades mangrove forests. • Hydrological restoration decisions and a warming climate can trigger vegetation species composition/dominance shifts by changing the soil porewater salinity regime and its interaction with fertility gradients. • The model can serve as a tool to guide wetland restoration management decisions. Hydrology is a critical driver controlling mangrove wetlands structural and functional attributes at different spatial and temporal scales. Yet, human activities have negatively affected hydrology, causing mangrove diebacks and coverage loss worldwide. In fact, the assessment of mangrove water budgets, impacted by natural and human disturbances, is limited due to a lack of long-term data and information that hinders our understanding of how changes in hydroperiod and salinity control mangrove productivity and spatial distribution. In this study, we implemented a mass balance-based hydrological model (RHYMAN) that explicitly considers groundwater discharge in the Shark River estuary (SRE, southwestern Everglades) located in a karstic geomorphic setting and influenced by regional hydrological restoration. We used long-term hydroperiod and porewater salinity (PWS) datasets obtained from 2004 to 2016 for model calibration and validation and to determine spatiotemporal variability in water levels and PWS at three riverine mangrove sites (downstream, SRS-6; midstream, SRS-5; upstream, SRS-4) along SRE. Model results agree with a distinct PWS pattern along the estuarine salinity gradient where the highest PWS occurs at SRS-6 (mean: 25, range: 22–30 ppt), followed by SRS-5 (17, 14–25 ppt) and SRS-4 (5, 3–13 ppt). A commensurate increase in PWS over a thirteen-year period indicates a long-term reduction in freshwater inflow coupled with sea-level rise (SLR). Increasing freshwater scenario simulation results show a significant reduction (17–27%) in PWS along the estuary in contrast with a high SLR scenario when salinity increases up to 1.1 to 2.5 times that of control values. Model results show that freshwater inflow and SLR are key drivers controlling mangrove wetlands PWS in this karstic coastal region. Given its relatively simple structure, this mass balance-based hydrological model could be used in other environmental settings to evaluate potential habitat and regime shifts due to changes in hydrology and PWS under regional hydrological restoration management. [ABSTRACT FROM AUTHOR]