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The community structures and ecosystem functions of floodplains are primarily driven by variation in flood inundation. However, global changes, such as invasive species and nutrient enrichment, may alter the effects of flooding in these systems. We added nitrogen (N) to correspond with twice the annual atmospheric deposition rate of the south-west Wisconsin, USA region within mature floodplain forest plots and patches of an invasive grass (reed canarygrass, Phalaris arundinacea) along a floodplain elevation gradient in an Upper Mississippi River floodplain forest. We measured soil physicochemical properties and the activity of six extracellular enzymes during 3 months that varied in flooding conditions. Multivariate analyses (distance-based redundancy analysis) revealed that floodplain elevation, month of sampling, and vegetation type were all significant predictors of variation in soil physicochemical properties, while elevation and month were significant predictors of multivariate extracellular enzyme activity (EEA). The best model for predicting EEA consisted of nitrogen availability, soil porosity, and water filled pore space. Although the categorical fertilization and invasion treatments were not significant predictors of EEA, our results suggest that their effects depend on the degree to which they modify N availability and soil moisture. In this system, spatial and temporal patterns in flooding appear to be the main driver of these properties, but N enrichment and invasion may have the potential to further modify them.

Biosecurity protocols designed to prevent further spread of invasive alien species have become a key component of invader management strategies. However, spread-prevention of invasive peracarids is especially difficult due to ineffectiveness of detection and treatment options. For instance, bloody-red mysid shrimp, Hemimysis anomala, is a high impact ecosystem-destabilising invader, which continues to spread in both Europe and North America. Here, we examine the effectiveness of two commonly used aquatic disinfectants (Virasure®/Virkon® Aquatic), and steam treatments (≥ 100 °C) to kill H. anomala. Specimens were exposed to 1% disinfectant solutions for complete immersion or mist-spray treatments, both lasting 60 s. Steam exposures lasted for 10 or 30 s. All treatments caused 100% mortality of H. anomala. Accordingly, it appears that relatively brief exposures to disinfectant and steam treatments can curtail further H. anomala spread. Therefore, these treatments should be used to decontaminate all equipment, from wetsuits to boats. In particular, steam and disinfectant spray treatments may be useful for decontamination of large, complex equipment, such as vehicles, trailers, outboard motors, or live wells on fishing boats.

Mangrove forests cover a small fraction of the earth’s surface, but contribute disproportionately to ecosystem services, including carbon (C) storage. These forests are being rapidly degraded as demand for economic development grows. In recognition of the multiple benefits of mangrove forests, rehabilitation of degraded forests is being carried out in many regions. This study assesses the potential for restored mangrove forests in Vietnam to sequester and store C, by characterizing two different mangrove restoration areas in the Mekong Delta region. The Can Gio Mangrove Biospheres Reserve (CGMBR) in Ho Chi Minh City was highly degraded during the Vietnam War and was subsequently replanted between 1978 and 1998. The Kien Vang Protection Forest (KVPF) in Ca Mau Province was similarly degraded during the war, but unlike CGMBR, it has experienced natural regeneration over the last 35 years. We find that vegetation structure between two sites are not different significantly, though CGMBR has richer mangrove species diversity than KVPF. The mean of total ecosystem C stocks in planted mangroves of CGMBR (889 ± 111 MgC ha−1) is not significantly different compare to natural regeneration forests of KVPF (844 ± 58 MgC ha−1). Our findings suggest that after 35 years, both anthropogenically and naturally regenerated mangroves appear to store similar levels of C.

Mangroves are one of the most productive, diverse ecosystems on the planet and serve as a protective barrier for coastal areas. Shrimps have a productive correlation with mangroves habitat, thereby large-scale shrimp farming pose a serious threat to mangroves ecosystems. The present study was carried out to estimate the total area under shrimp farming in the intertidal regions of Kannur district. From the study, we have documented 140 shrimp ponds, which contributes to a total area of 524.4 ha. We found that active shrimp farming area in the district is 524.4 ha in 2020. The traditional shrimp farming method accounts for 60.6% of the total farmed area while non-traditional shrimp farming accounts for 36.9% of the total farmed area; both types are expanding fast in the district. Of the five major Rivers in the district, Kuppam River has the majority of the shrimp farms followed by Dharmadam River. Penaeus monodon, Litopenaeus vannamei and Penaeus indicus are the shrimp species cultivated in the district. Since shrimp farms are created by replacing the mangrove habitats in the intertidal region, mangroves of Kannur district are under threat and needs serious intervention for long term survival.

The study of five mangrove forests was undertaken during the summer of1998 on the north coast of Haiti. Photo-interpretation detected areachanges between 1978 and 1989; the areas were reduced by an averageof 43% each. Two of the sites, Salée River mangrove andHaut-du-Cap River mangrove, were characterized by means of a vegetationsurvey and water and soil analysis. Tree density averaged 58,750 stems/haand 114,250 stems/ha respectively, while tree height averaged 2 m.Interviews with villagers indicated that all the assessed mangroves areintensively harvested for charcoal and fuel wood. This extraction seems tobe the main human disturbance, resulting in changes in forest structure,although heavy fishing and conversion to residential sites constitutedisturbances in some mangroves. The situation is critical but probably notirreversible. However, the socio-economic and environmental conditionsprevailing in the country and the lack of basic information on Haitianmangroves are major obstacles to their preservation.

The extent of coastal wetlands in Georgian Bay is controlled primarily by the water level of Lake Huron, which directly affects the amount of critical habitat available for fish and wildlife communities. Lake-levels have historically fluctuated by nearly 2 m and that range could increase in the future. This prompted us to investigate how quantity and quality of wetland habitat in Georgian Bay may be affected by different lake-level scenarios. The extent of low-marsh habitat was modeled with a generalized linear model that used hydrogeomorphic features (i.e. depth, slope, and exposure) as predictors. We simulated lake levels between 175.5 m and 177.5 m at 0.5 m-increments, and found that the total area of low marsh peaked at 176.0 m (7113 ha) and declined sharply as lake levels increased or decreased. In contrast, low-marsh volume was highest at 176.5 m (3.84 × 107 m3) but remained relatively stable across all modeled lake levels. We derived an average elevation profile for low-marsh habitat across the study area that showed a shallow “step” between 175.5 and 176.0 m, flanked by steeper upslope and downslope sections. At historically low lake levels low-marsh habitat would have been dominated by shallow water (< 0.5 m), whereas at higher lake levels it would have been dominated by deeper (0.5–2.0 m) water. The geomorphology at low lake levels (i.e. 176.0 m) appears to favour large areas of shallow habitat at the expense of deeper habitats that could have supported more structurally complex, submersed aquatic vegetation.

Microbial respiration (Rm) and ecoenzyme activities (EEA) related to microbial carbon, nitrogen, and phosphorus acquisition were measured in 792 freshwater and estuarine wetlands (representing a cumulative area of 217,480 km2) across the continental United States as part of the US EPA’s 2011 National Wetland Condition Assessment. EEA stoichiometry was used to construct models for and assess nutrient limitation, carbon use efficiency (CUE), and organic matter decomposition (− k). The wetlands were classified into ten groups based on aggregated ecoregion and wetland type. The wetlands were also assigned to least, intermediate, and most disturbed classes, based on the extent of human influences. Ecoenzyme activity related to C, N and P acquisition, Rm, CUE, and − k differed among ecoregion–wetland types and, with the exception of C acquisition and − k, among disturbance classes. Rm and EEA were positively correlated with soil C, N and P content (r = 0.15–0.64) and stoichiometry (r = 0.15–0.48), and negatively correlated with an index of carbon quality (r = − 0.22 to − 0.39). EEA stoichiometry revealed that wetlands were more often P- than N-limited, and that P-limitation increases with increasing disturbance. Our enzyme-based approach for modeling C, N, and P acquisition, and organic matter decomposition, all rooted in stoichiometric theory, provides a mechanism for modeling resource limitations of microbial metabolism and biogeochemical cycling in wetlands. Given the ease of collecting and analyzing soil EEA and their response to wetland disturbance gradients, enzyme stoichiometry models are a cost-effective tool for monitoring ecosystem responses to resource availability and the environmental drivers of microbial metabolism, including those related to global climate changes.

Seventeen estuaries that are permanently open to the sea provide habitat for mangrove forests along the Eastern Cape coast, South Africa. These mangroves are of interest as they occur at one of the most southerly distributions in the world. Climate change will influence future distribution patterns while present anthropogenic impacts are causing mangrove loss. Mangrove area and species distribution in 2012 were compared with results from previous studies in 1982 and 1999. Anthropogenic impacts were noted and showed that harvesting of mangrove wood, livestock browsing and trampling and footpaths occurred in more than 70 % of the estuaries. Browsing on trees by cattle resulted in a clear browse-line and browsing on propagules mainly by goats reduced seedling establishment. Over the past 30 years, a total loss of 31.5 ha of mangroves was observed for all 17 estuaries. However in three estuaries mangroves had re-established where they had been previously lost. Extreme events such as floods and closure of the estuary mouth to the sea caused large changes in mangrove area in small estuaries. In contrast in the larger forests which occurred in the larger estuaries, anthropogenic pressures such as harvesting reduced the area of mangroves. Predicted climate changes coupled with anthropogenic impacts are likely to accelerate the loss of mangroves. More sustainable practices are urgently needed to protect biodiversity and the ecosystem services that these forests provide.

Stable isotopes 2H and 18O of fog drip water, lake water, soil profiles, and vegetation leaves in Junshan wetland of East Dongting Lake, China, were investigated to estimate the contribution of fog drip water to wetland vegetation. Because of its recycled terrestrial meteoric water source, fog drip water is characterized by isotopic compositions that plot above the local meteoric water line (LMWL). Lake water undergoes intense evaporation owing to its low water volume and long residence time. The isotopic compositions of soil water suggest that it is recharged by both recent rainfall and fog drip water. A binary mixing model shows that approximately 16% of unsaturated soil water originates from continuous recharge by fog drip water, reaching 31% in surface soil where the vegetation roots are mainly distributed. Inspired by the literatures on acidification of intercepted clouds and fog as the major factor in forest die-back in Europe, the findings in this study inform future investigations into the relationships between fog water deposition and wetland degradation especially in heavily industrialized foggy areas.