Wetlands Ecology and Management最新文献

Coastal marshes face increasing pressures from climate-related environmental stressors, adversely affecting their biota like plants and microbes. Understanding how marsh communities are influenced by their environment is critical in determining their ability to respond to environmental stressors. Plants harbor microbes that colonize and inhabit their tissues without causing apparent harm (‘endosymbionts’). These endosymbionts provide benefits to host plants including mediation of salinity stress response, thus it is important to understand the factors influencing the diversity of endosymbiont communities. We examined the relative influences of biotic (host-related) and abiotic (local environment) factors on the endosymbiont communities associated with the dominant saltmarsh halophyte, Batis maritima. Using culture-based and genetic approaches, we characterized both fungal and bacterial endosymbionts from B. maritima roots in Oso Bay, Texas, along the Gulf of Mexico. Isolation frequency of endosymbionts significantly differed between fungi and bacteria, and the overall diversity was low. Belowground plant biomass and salinity correlated with decreased diversity in fungi, while shifts in fungal composition varied according to light availability. Overall, these findings highlight the relative influences of both biotic and abiotic factors in shaping the root endosymbionts and might differ between fungi and bacteria. Understanding these processes is fundamental to determining the resilience of both endosymbionts and host plants, with implications for ecosystem functions amidst environmental pressures. As anthropogenic-driven environmental changes continue to rise, insights gained from these results can inform future coastal restoration and management especially of at-risk coastal ecosystems.

Land-cover change dynamics were investigated in a Mediterranean coastal wetland to evaluate the long-term effectiveness of nature reserve management. A multitemporal analysis of land cover maps was conducted, utilizing visual interpretation of aerial orthophotos from the summer seasons of 1996, 2008, 2015, and 2021. Landscape changes were evaluated by transition matrices and chord diagrams. Maps were classified in accordance with CORINE land cover types at a fourth level of detail. The multitemporal analyses provided a comprehensive overview of landscape changes within the reserve over the past 25 years. The most notable changes were the increase of wetland areas and the reduction of agricultural and artificial areas. Moreover, seminatural vegetation constantly extended over time. These changes reflected the continuous management activities within the nature reserve, encompassing agreements for water supply, restoration projects, and measures to counteract illegality. These operational actions induced fine-grained ecological changes (outcomes at ecosystem level). This study highlighted the importance of remote sensing and landscape analysis, matched with fine-grained management data, as tool for long-term monitoring. Such an approach provides valuable support in evaluating the effectiveness of strategies promoted in nature reserves hosting wet coastal ecosystems of high conservation concern.

This study assessed Ghana’s national and international environmental commitments, laws and policies and the stakeholders’ capacity to protect and manage the wetlands of a metropolis, Kumasi. The methods adopted included field surveys, desk studies (literature review), and interviews with various stakeholders. The results show that despite the sprawling urbanisation, patches of wetlands exist with relatively high diversity. The study further reveals that Ghana is a signatory to many international environmental conventions and treaties irrespective of the required obligations and commitments. However, the translation of the obligations of these conventions and treaties into local laws and policies, their implementation and enforcement have been woefully inadequate. Institutions mandated to oversee these processes are under-resourced or undermined by a multitude of issues. Whilst the Kumasi Metropolitan Assembly and its planning and hydrological units have the personnel and technical competence to deal with wetland issues, the National Disaster Management Organisation, on the contrary, has the financial and logistical support without the needed technical competence to manage wetland and flood challenges. For a developing country like Ghana, an integrated and collaborative approach between stakeholders is advocated based on a model that focuses on social and technical management of floods and wetlands for implementation by these stakeholders.

Anthropogenic inputs of heavy metals and metalloids pose a risk to wetlands due to their long retention time in sediment, high toxicity at low concentrations, and biological accumulation. This study aimed to assess risk from seven heavy metals (cadmium:Cd, chromium:Cr, copper:Cu, mercury:Hg, nickel:Ni, lead:Pb, zinc:Zn) and one metalloid (arsenic:As) along a trophic pathway by quantifying contaminant loads in muskrat livers, roots of invasive hybrid cattail (Typha x glauca), and in sediment at Horicon National Wildlife Refuge, a wetland of international importance in southeastern Wisconsin, United States. Overall, comparison to literature and thresholds from the Environmental Protection Agency led us to conclude that heavy metals and metalloids pose a low risk to refuge biota with maximum concentrations as follows in sediment, T. x glauca roots, and muskrat livers in mg/kg dry weight: Zn—82, 54, 111, Pb—42, 43, 0.06, Cu—26, 59, 13, Ni—22, 5, 0.7, Cr—20, 3, 0.5, As—6, 11, 0.08, Cd—3, 1, 0.08, Hg—0.1, 0.02, 0.08, a finding which was further supported by low bioconcentration factors between sample types. A spatial analysis using GIS revealed hotspots for Cd, Cr, Cu, Ni, and Zn in sediment in one subplot. However, even in hotspots concentrations mostly fell below protective thresholds and were similar to or lower than concentrations found in a prior survey from 1990 (α < 0.05). Overall, while anthropogenic influences are undoubtedly present, we interpret the concentrations found here to be relatively low and present them as points of comparison regarding risk to plants and mammals for others conducting similar surveys on wetlands.

Spartina anglica, an invasive marsh grass, was designated as a harmful marine organism in 2016 due to its ability to stabilize mudflats and reduce macrobenthic diversity. To control such invasive species, physical, chemical, or biological methods can be applied while chemical methods are prohibited by law due to ecological disruption. However, the preferred methods of soil tillage, cutting, and native plant restoration for managing S. anglica have rarely been analyzed. To compare the methods, we performed 9 treatments with four replicates, comprising control, different frequencies of clipping (once and twice) and tilling (once and twice), and different densities (50 and 100 seedling) of restoration of the native plants Suaeda japonica and Phragmites australis. To evaluate the severity of disturbance, we measured coverage, stem density, average plant height, and above-ground biomass for 2 years. We found P. australis and S. japonica did not successfully establish or survive due to niche differences and the inherent biological features of Spartina. However, physical removal had a stronger effect than interspecific interaction. Two cutting treatments in the early and the late growing season reduced plant height and biomass of S. anglica by 6 and 34%, respectively, compared with the control treatment at the rapid vegetative growth stage in the following year. We also found that two tillage treatments reduced biomass, plant cover, and stem density by 32%, 38%, and 83%, respectively, in the following year. In the study site, managing invasive species such as S. anglica is best achieved by physically destroying the plant using soil tillage while attempting to restore native species had marginal control effects.

Recent outbreaks of the West Nile virus have been reported in southern Spain, a region with important wetland habitats for migratory birds. Here, we analyzed the role of species association and abiotic parameters on the abundance of seven mosquito species in the Doñana National Park, Spain. We applied the Joint Species Distribution Models (JSDM), using the Hierarchical Modeling of Species Communities approach to simultaneously model the effect of habitat type, normalized difference vegetation index, hydroperiod, distance to rivers, land surface temperature, and the abundance of seven mosquito species. We created three models with varied parameters and evaluated the effects of abiotic parameters and species-to-species associations, which served as proxies for species interactions. Our models estimated the species-specific responses of the mosquito community to abiotic parameters. A positive association was identified within the Culex community with potential biotic interactions. However, Ochlerotatus caspius, Ochlerotatus detritus, and Anopheles atroparvus had no statistically significant association with each other and with the Culex species after accounting for the effect of abiotic parameters. We also found that the potential species associations estimated at particular sites and abiotic parameters influenced the model projection for the average abundance of mosquito species. The JSDM will allow spatial projection of the abundance of each mosquito species, which is an important parameter for epidemiological models. The JSDM inference of species association is important because predation, competition, and facilitation affect the distribution and abundance of different species.

Organic matter is sometimes added to soil in wetland mitigation projects, putatively to improve restoration outcomes. At a freshwater mitigation wetland, built in a former agricultural field to compensate for development-related wetland losses elsewhere, we conducted a manipulative field experiment using organic matter amendments to identify the effects different types and loading rates had on the development of soil (organic matter, bulk density, and hydric soil indicators), vegetation (root and shoot biomass, floristic quality), and methane (CH₄) emissions. The amendments included cow manure, composted wood chips, and hay at various loading rates, and municipal wastewater Class A biosolids. We found that there were trade-offs in desired restoration outcomes. Experimental loading rates of hay (226 m³ ha⁻¹) and manure (339 and 678 m³ ha⁻¹) produced more CH₄ (78–92 g m⁻² year⁻¹) than unamended plots (28 g m⁻² year⁻¹). These same amendments had little effect on hydric soil indicators (e.g., redox potential and reduced iron). Manure almost doubled vegetation biomass (937 g m⁻² versus 534 g m⁻²) compared to the unamended control, largely due to the growth of Typha sp. (cattail), an undesired plant at this site that resulted in lower floristic quality. Compared to unamended soils, only wood chips appeared to increase soil organic matter after one growing season. All amendments tended to reduce soil bulk density and penetration resistance, but these were not correlated with root growth. Unexpectedly, hydrology varied considerably due to patchy soil characteristics, despite little variation in elevation – this strongly influenced on our results. We qualitatively observed that constantly inundated plots had lower CH₄ emissions than areas with wet-dry cycles and that cattail proliferated mostly in wetter areas. Contrary to the prescription of organic matter amendments as a method for accelerating soil and vegetation development in wetland restoration projects, our findings demonstrate that amendments may not be necessary to support vegetation and hydric soil development and might unnecessarily exacerbate atmospheric warming and contribute to invasive species spread.

The zooplankton community was analysed in two intermittent salt lakes in Serbia – Lake Velika and Lake Mala Rusanda. Samples were collected twice a month during the wet phase between March and May. A total of 15 zooplankton taxa were identified. Crustaceans were more diverse in Lake Mala Rusanda. The communities of both lakes were composed mainly of cosmopolitan, generalist, euryhaline species. Strictly haline species such as Brachionus asplanchnoidis and Arctodiaptomus spinosus were the dominant components of the zooplankton communities in both lakes. Arctodiaptomus spinosus was most abundant in March and April, accounting for up to 50% of all zooplankton specimens found in a sample. The proportion of juvenile stages of A. spinosus was highest in the March and early April samples. The ratio of males to females varied and was likely related to swarming behaviour as part of the species’ reproductive strategy.

Understanding the complexity of forest community dynamics is essential in forest management planning and stewardship, yet lowland northern white-cedar (Thuja occidentalis L.) are often managed as homogenous communities. Through this study, we defined lowland white-cedar forest community types in unharvested and harvested forest stands within the State of Michigan and examined community type associations with ecological variables. Data collected in unharvested stands revealed three white-cedar community subtypes: (1) cedar-deciduous, (2) cedar-conifer, and (3) cedar-shrub. These unharvested subtypes were dominated by white-cedar, yet characterized by different soils, hydrology, geochemical gradients, and associated tree species. In harvested stands, six community types were identified: (1) aspen-fir, (2) winterberry-willow, (3) balsam fir, (4) cedar-red maple, (5) cedar-black spruce, and (6) alder-tamarack. These harvested community types were located along ecological gradients, including soil type (organic or mineral) and soil water pH. Using community types in unharvested and harvested stands, and associated ecological gradients, potential pathways of compositional transition were theorized. Findings suggest that cedar community subtype affects the likelihood of cedar regeneration and dictates the alternative species replacing cedar after harvest. These findings and potential pathways are useful to forestry practitioners, as they highlight potential changes in tree species dominance following harvest across a range of lowland white-cedar community types, allowing refinement of silvicultural prescriptions to ensure desired outcomes.

Abstract

Wetlands provide extensive ecological services for life on Earth, but they are facing rapid global disappearance under the influence of human activities and climate change. Therefore, it is of great importance to ensure the wise use of wetlands. Local residents’ attitudes toward sustainable tourism in wetlands are essential to the sustainable management and wise use of this resource. This study examined the attitudes of local communities towards sustainable wetland tourism in three wetland areas in Northern Serbia. The survey was implemented to 1078 households randomly selected from seven communes (20 settlements) adjacent to chosen Ramsar sites. Using SPSS 25, the data was subsequently processed, assessed, and explained. In addition to descriptive statistics, a correlation was used to determine the factors that affect locals’ attitudes toward the development of sustainable wetland tourism. The study shows that local residents generally hold positive attitudes towards sustainable wetland tourism. Age, length of residency, gender, employment, education and income are observed to be significantly impacting attitudes toward sustainable wetland tourism. Although there is a high level of awareness of the risks to wetlands, there is doubt regarding their understanding of the state of wetlands’ protection and the particular issues they face. On the other hand, there is no doubt that locals are ready to protect wetlands for upcoming generations. For sustainable wetland tourism, management, and conservation, it is crucial to connect management organizations, tourism representatives, and people. In this matter, it is important to improve communication and connection between the mentioned stakeholders.