Wetlands最新文献

There are over 700 aquatic ecological assessment approaches across the globe that meet specific institutional goals. However, in many cases, multiple assessment tools are designed to meet the same management need, resulting in a confusing array of overlapping options. Here, we look at six riverine wetland assessments currently in use in Montana, USA, and ask which tool (1) best captures the condition across a disturbance gradient and (2) has the most utility to meet the regulatory or management needs. We used descriptive statistics to compare wetland assessments (n = 18) across a disturbance gradient determined by a landscape development intensity. Factor analysis showed that many of the tools had internal metrics that did not correspond well with overall results, hindering the tool’s ability to act as designed. We surveyed regional wetland managers (n = 56) to determine the extent of their use of each of the six tools and how well they trusted the information the assessment tool provided. We found that the Montana Wetland Assessment Methodology best measured the range of disturbance and had the highest utility to meet Clean Water Act (CWA§ 404) needs. Montana Department of Environmental Quality was best for the CWA§ 303(d) & 305(b) needs. The US Natural Resources Conservation Service’s Riparian Assessment Tool was the third most used by managers but was the tool that had the least ability to distinguish across a disturbance, followed by the US Bureau of Land Management’s Proper Functioning Condition.

Protected areas (PA) are being stifled by human land uses, jeopardizing their integrity and ecosystem services. Therefore, we searched for human land use within 19 PAs of the Pantanal ecoregion. We assessed changes in land cover from protected areas’ creation year up to 2021. In addition, we established a 10 km buffer from each PA limit to compare trends in the landscape inside and outside PAs. Our results indicated the presence of pasture fields in eight PAs analyzed. We also detected a decrease in open water areas and a slight variation in native vegetation over the years. There was an increase in grassland and savanna areas, while forest, wetland, and pasture fields did not change over the years. Of all 19 buffer zones, 15 had human land uses. In addition to an increase in the human land use area, buffer zones showed an increase in grassland cover and a decrease in the open water cover. Terrestrial environments within most Pantanal PAs still stand to human interventions. Still, the human land use in reserves where it is not allowed indicates management issues and low law enforcement. Unfortunately, aquatic environments’ protection is more challenging, depending on actions at lowlands and surrounding plateaus that harbor the headwaters. There is a clear need to integrate warming and drying impacts in the protected areas management plans. Since we have no control over large-scale climate, we must focus more on mitigating regional climate from a land use perspective.

Peatland margins are a distinct ecotone especially vulnerable to deep smouldering in the Boreal Plains because they can experience greater water table drawdown during dry periods compared to peatland middles. Margin recovery trajectories have potentially important implications for wildfire behaviour as both the rate of vegetation recovery and community composition control fuel load and flammability. We compared peatland margin and middle vegetation trajectories using a chronosequence of time-since-fire in boreal Alberta, Canada. Margins had unique post-fire indicator species, with a higher broadleaf cover and limited Sphagnum moss colonization. Middles and margins became less distinct with greater time-since-fire, where both were dominated by feathermoss as canopy closure increased. High burn severity in margins can expose the seedbank in the underlying mineral soil to favourable conditions, causing rapid accumulation of broadleaf aboveground biomass and limiting Sphagnum establishment. The rapid accumulation of aboveground biomass increases potential fuel load, while exclusion of Sphagnum increases future smouldering potential given the dense peat in the margin ecotone. However, the dominance of deciduous vegetation for several decades post fire would serve to limit wildfire compared to a conifer-dominated system, particularly post leaf-out. Thus, peatland margins could represent a positive feedback to peat carbon loss for early season fires and a negative feedback for post leaf-out fires due to the interplay between fuel load, fire seasonality, and species flammability. Characterization of margins as distinct ecotones with a separate vegetation structure and species composition from peatland middles provides critical insight about wildfire vulnerability and carbon storage in the Boreal Plains.

Coastal wetland communities provide valuable ecosystem services such as erosion prevention, soil accretion, and essential habitat for coastal wildlife, but are some of the most vulnerable to the threats of climate change. This work investigates the combined effects of two climate stressors, elevated temperature (ambient, + 1.7 °C, + 3.4 °C, and 5.1 °C) and elevated CO₂ (eCO₂), on leaf physiological traits of dominant salt marsh plant species. The research took place at the Salt Marsh Accretion Response to Temperature eXperiment (SMARTX) at the Smithsonian Environmental Research Center, which includes two plant communities: a C₃ sedge community and a C₄ grass community. Here we present data collected over five years on rates of stomatal conductance (g_s), quantum efficiency of PSII photochemistry (F_v/F_m), and rates of electron transport (ETR_max). We found that both warming and eCO₂ caused declines in all traits, but the warming effects were greater for the C₃ sedge. This species showed a strong negative stomatal response to warming in 2017 and 2018 (28% and 17% reduction, respectively in + 5.1 °C). However, in later years the negative response to warming was dampened to < 7%, indicating that S. americanus was able to partially acclimate to the warming over time. In 2022, we found that sedges growing in the combined + 5.1 °C eCO₂ plots exhibited more significant declines in g_s, F_v/F_m, and ETR_max than in either treatment individually. These results are important for predicting future trends in growth of wetland species, which serve as a large carbon sink that may help mitigate the effects of climate change.

Depth patterns of δ¹³C and δ¹⁵N values in peatlands are used to reconstruct their environmental history, e.g. their hydrology, temperature changes and degradation. However, the suitability of δ¹³C and δ¹⁵N as proxies for environmental reconstructions needs to be verified by studies in a diverse range of environments. We present a study on the influence of aeolian deposits on δ¹³C and δ¹⁵N values in peatlands in Iceland. Large areas in Iceland comprise highly active aeolian environments due to tephra from volcanic eruptions, and material from eroding drylands. The study is a first step toward assessing if depth profiles of δ¹³C and δ¹⁵N values can provide insight into the environmental history of peatlands in aeolian environments. We compare δ¹³C and δ¹⁵N values with several conventional proxies of decomposition (dry bulk density, C/N ratio and two ratios derived from ¹³C NMR spectra). We also interpret variations in δ¹³C and δ¹⁵N values in relation to the pedogenic minerals allophane and ferrihydrite and total mineral content. The complexity of depth trends of δ¹³C and δ¹⁵N values increases with proximity to source areas of windborne material. Particularly, there are turning points adjacent to major tephra layers. These patterns appear to be related to the influence of the volcanic deposits on factors like hydrology and fertility of the peatlands, microbial activity and vegetation composition. Depth trends of δ¹³C and δ¹⁵N values in peatlands of aeolian environments need to be interpreted in relation to other proxies reflecting the organic matter chemistry, and mineral soil constituents.

Tropical peatlands are highly vulnerable to anthropogenic alterations. In Costa Rica, riverine peatlands are understudied, and most are not included in protected areas. This study aims to generating information useful to assess the anthropogenic pressure in a riverine peatland in Los Robles Sector (LRS) of Medio Queso Wetland (MQW) complex. Evaluations of impacts of fires on vegetation and surface peat chemistry, and the post-2021 fire, makeup of dominant vegetation changes with the Cyperaceae species Scleria melaleuca replacing Eleocharis interstincta as the dominant species are presented. The topsoil (0–20 cm) total C content was quantified as lower than 300 g kg⁻¹ with no significant statistical differences in total C and N content between soil shortly after the fires or two years later. The species E. interstincta is observed to promote higher C stability during the dry season, and has a more recalcitrant composition of the root system compared to the post 2021-fire dominant S. melaleuca. To reduce the impact on C accumulation, measures to prevent grazing-originated fires, especially when the water table is low, are urgent. Hence, this work aims at proving information that can be a baseline for impacts assessment and to inform conservation measures and policies.

Constructed wetland is typically occupied on the urban area, which emulates the function of natural wetland. It is necessary to supply nutrients that vegetation can absorb for its growth thus sustaining the nature system where represents as vegetation. Phosphorus is one of the essential nutrients for the growth of vegetation, whereas in natural wetlands the amount of phosphorus available for the growth of vegetation is insufficient. In this study, Phosphate Solubilization Microbe (PSM) was used for changing the phosphate’s chemical structure in wetland by its metabolism. Therefore, if PSM is added in wetlands, it is expected that the phosphorus removal mechanism by vegetation can be microbially boosted by the PSM. The PSM activity was measured from the soil sampled in advance, and then the experiment was conducted by culturing PSM in string media, excluding vegetation in the wetland module, and varying the concentration of phosphorus and the numbers of media. It was found that the concentration of the available phosphorus was proportional to the number of media by showing the more than half of conversation ratio orthophosphate into the available phosphorus. This study was conducted for verifying hypothesis that PSM might be help to activate a wetland environment without vegetation and PSM can be very useful to environmentally activating a wetland at the beginning of its formation and establishment in nature or after the winter season when the environment of wetland is relatively dormant.

Littoral wetland plant species such as Typha domingensis and Schoenoplectus californicus both locally called tul provide diverse ecosystem services (ES) in Lake Atitlan. These ES include removal of pollutants, oxygenation, and raw material for handicrafts. Human communities, most of whom are Indigenous Maya, actively steward littoral wetlands informed by their traditional ecological knowledge (TEK). Our goal was to assess the wetland condition in four Maya Tz'utujil communities (Santiago Atitlan, San Pedro, San Juan and San Pablo La Laguna, Guatemala), each with different management practices. We used a four-level wetland condition assessment: (1) littoral vegetation extent measured with remote Sentinel-2 and Google Earth photographs; (2) field plant surveys to measure vegetation structure and plant diversity; (3) wetland stressor assessment (stressors analyzed were land use, non-native macrophyte species [Hydrilla verticillata] and lake-level fluctuations); and (4) interviews with Maya Tz’utujil tuleros, fishers and artisans. Santiago stood out as having the highest cover and number of patches for all three species, reflecting its distinctive characteristics (e.g., lakeshore landforms and extent of wetlands) and the role of Indigenous wetland management. Of the four Maya communities, Santiago and San Juan had healthier wetlands despite being most affected by fluctuations in lake water level, reflecting the value of traditional management practices. Indigenous wetland management, informed by TEK, includes actions that sustain wetlands from stressors and global changes, including tul planting, harvesting, and extraction of non-native invasive macrophytes. Ecological value embedded in Indigenous resource management suggests the need to include these practices in governmental environmental management and policy.

Wetlands in southern Ontario are at risk of degradation and alteration due to human activities. This is a concern because wetlands provide essential habitat for species from a range of taxa, such as birds and anurans (frogs and toads). One wetland-dwelling species whose decline may be linked to loss of wetland wildlife habitat is the muskrat (Ondatra zibethicus). The decline of muskrats may also be linked to declines of other species because muskrats engage in activities that could support taxa such as birds and anurans by increasing habitat heterogeneity. We investigated whether bird and anuran species richness is related to muskrat density or if it is better predicted by land cover variables that describe the wetland and surrounding area at 30 coastal wetlands on Lake Ontario. We estimated bird and anuran species richness using data from the Great Lakes Marsh Monitoring Program and the Great Lakes Coastal Wetland Monitoring Program, and muskrat density based on muskrat house counts. Our results suggest that muskrat activity did not predict richness of anurans or birds overall; however, it did predict richness for the subset of birds that nest in emergent aquatic vegetation. Our results indicate that muskrat abundance in emergent marshes may increase habitat quality for birds that nest in emergent vegetation but may not have a measurable effect on anuran diversity in these same wetlands.

Abstract

With increasing threats from climate change and direct human impacts to coastal systems, vulnerability assessment approaches have been developed to enable prioritisation of management actions. This study reviewed vulnerability assessment literature about saltmarsh, beach and mixed shoreline systems published in English. Literature searches and NVivo software were used to analyse literature available, indicative of patterns and gaps in research. Results showed thirteen different methods used in selected literature to assess vulnerability, and the most commonly used was the indices approach. In saltmarsh systems, most articles employed unique methods rather than repeating established ones, and spatial change methods were rare. The majority of research did not include definitions of vulnerability or an indication of which conceptualisation of vulnerability was being used. Most literature assessed vulnerability to climate change and sea level rise, rather than natural hazards or other human impacts. The mangrove vulnerability assessment literature was far more voluminous relative to applications to beach, saltmarsh or mixed such systems. This review identifies how future research can better assess gaps in knowledge, and progress more unified understanding of coastal vulnerability.