Wetlands最新文献

Four representative halophytes, Tamarix chinensis (Tc), Phragmites australis (Pa), Suaeda salsa (Ss), and Spartina alterniflora (Sa), in the Yellow River Estuary wetland were selected to clarify the root disturbance on soil nutrient elements, salt ions, and their stoichiometric ratios. The results showed that the average total organic carbon (TOC) content of Tc, Pa, Ss, and Sa in the rhizosphere (RS) group was 5.19, 2.15, 2.05, and 2.14 times higher than those in the non-rhizosphere (CK) group, respectively. The total nitrogen (TN) content of Tc in the RS group was about 3.44 times that of the CK group. The average soil salinity reduced by 41.35%, due to the root disturbance of Tc. Soil ions, including K⁺, Ca²⁺, Mg²⁺, Na⁺, Cl^-, and SO₄^2- reduced by 33.86-62.86%. The root disturbance of Pa reduced soil salinity and soil ions by 35.47% and 16.93%-46.85%, respectively. However, the root disturbance effects in Sa and Ss were not obvious. The disturbance of roots played a crustal role in affecting the spatial heterogeneity of soil properties in the coastal wetlands above the intertidal zone (Tc and Pa), but its effect was greatly weakened below the intertidal zone (Sa and Ss). These findings are important for understanding how halophytes can impact soil nutrient levels and salt concentrations in coastal wetlands, which is crucial for effective management and restoration.

Wildfires and deforestation are severe threats to global ecosystems. In Brazil, Cerrado (a tropical savanna) and Pantanal (a tropical wetland) biomes have undergone several changes over the years due to anthropic actions. Both deforestation in Cerrado biome and wildfires in Pantanal have increased lately. Some studies argue that both processes could be related, but there is a scarcity of quantitative analysis evaluating that. In this context, making use of machine learning techniques and temporal data obtained by Remote Sensing in the period 2000–2020, this study aimed to identify the interactions between Cerrado land use and land cover change in native vegetation and wildfires incidence in Pantanal. Our results corroborate that and show that wildfires in Pantanal were directly linked to large-scale and commodities agriculture conversion in Cerrado, as well as native vegetation loss and hydrological changes in Pantanal.

Urban rivers face sustained anthropogenic pressures limiting biodiversity. Yet, urban waterways such as the Detroit River are important habitat in supporting regional diversity. The Detroit River is a Great Lakes Area of Concern where conservation and restoration efforts prioritize improved biological and habitat integrity in the connecting channel. This study explores benthic macroinvertebrate in submerged aquatic vegetation across five mainstem channel wetlands and two tributary sites of the Canadian wetlands to describe spatial patterns and diversity. We first examine inter-wetland differences between five mainstem wetlands by hierarchical cluster analysis, NMDS and PERMANOVA, identifying two mainstem groups: one comprising of two middle reach wetlands (Detroit River Marshes and Grass Island), the second showed similarities among wetlands across all reaches (Turkey Creek, River Canard and Peche Island). The latter groupings shared similar habitat characteristics, deeper and finer grain-sizes, and functional feeding group characteristics - low abundances of shredders. Second objective, we perform an intra-wetland comparison for Turkey Creek and River Canard to analyze for differences along tributaries. At neither River Canard nor Turkey Creek we observed significant tributary influence on mainstem communities but had found the Turkey Creek tributary communities significantly differed from the channel communities. Diversity metrics and Hilsenhoff Biotic Index illustrate strained benthic communities across the river. We had also found water quality to be consistently moderately degraded. Our findings differ from prior analyses within emergent vegetation that indicate variable water quality conditions between mainstem and tributary and non-impaired macroinvertebrate communities.

Wetlands serve as unique habitats that can support high biodiversity. Large-scale loss of wetland habitats can threaten important linkages between lake and wetland habitats that could affect diversity and growth of aquatic organisms. In this study, we compare prey diversity and abundance as well as Walleye (Sander vitreus) diets and condition in a large glacial lake (Lake Kampeska, South Dakota) with a connected wetland to better understand seasonal changes in the benefits provided by each habitat. We examined seasonal differences (spring, summer, and fall) through two years (summer 2021 through fall 2022) between the habitats using prey fish catch per unit effort, richness, Shannon diversity, and Bray–Curtis dissimilarity as well as Walleye relative weight, percent of empty stomachs, diet weight, stomach fullness, diet energy, and diet taxa importance. The prey fish community was more diverse and abundant in the wetland, and Walleye consumed more prey (by weight) in the wetland during all seasons except spring. Wetland reconnection can be a tool for managers to improve water quality while providing seasonal habitat needs for fish. Additionally, the diversity of prey resources provided by wetlands, many of which are unique, support resilience in the face of ecological change. Protection of wetlands may be critical for maintaining healthy and resilient fisheries into the future.

The success of the D-Day landings during World War II was significantly influenced by the detailed reconnaissance and scientific analysis of coastal substrate, particularly peatlands, by Allied wetland scientists. This paper examines the critical role of wetland science in ensuring the feasibility of the Normandy invasion. Initial geological intelligence raised concerns about the stability of the beaches due to extensive peat deposits underlying the Normandy coast. To address uncertainties, the Combined Operations Pilotage Parties (COPP) conducted covert beach surveys, collecting substrate samples crucial for operational planning. These missions, undertaken under challenging conditions, identified suitable landing areas by analysing sediment composition and bearing capacities. The success of D-Day was, in part, attributed to the insights provided by wetland scientists, who highlighted the significance of substrate properties in operational success. Their contributions underscored the interdisciplinary nature of wartime planning, integrating scientific expertise with military strategy. This study illuminates the often-overlooked role of wetland science in pivotal historical events, emphasising its influence on strategic decision-making and operational outcomes during one of the 20th century’s defining battles.

The conversion of organic matter by extracellular enzymes can reveal important insights into carbon and nutrient cycling. The activity and stoichiometry of hydrolytic extracellular enzymes were investigated to assess the effects of vegetation cover and sediment characteristics on microbial-enzyme-mediated decomposition in coastal ecosystems. Extracellular enzyme activity (EEA) was quantified across transects extending from mangrove to tidal flat habitats in two New Zealand coastal ecosystems that differ in mud content (sandy: Hobson Bay, muddy: Snells Beach). We determined the activity of five key hydrolyzing enzymes: β-glucosidase (hydrolyzes cellulose to glucose); β-N-acetylglucosaminidase (catalyzes the terminal reaction in chitin degradation); alkaline phosphatase (releases soluble inorganic phosphate groups from organophosphates); β-D-cellobiohydrolase (hydrolyzes cellulose to generate cellobiose); and β-xylosidase (catalyzes hemicellulose). All enzymes involved in C acquisition and in N and P cycling had higher activity at the muddy site. No habitat differences in EEA were observed at the sandy site, whereas EEA was lower in the non-vegetated habitats for some enzymes at the muddy site. Models of microbial metabolic limitations highlighted that most habitats at both muddy and sandy sites were predominately C and P limited. The EEA in these coastal wetlands was generally lower than has been reported for other terrestrial, freshwater, and estuarine ecosystems, with values often one to two orders of magnitude lower than other wetland studies. These results can be used to advance our understanding of the biogeochemical processes underpinning the response of coastal ecosystems to land-derived nutrient and sediment inputs.

In Japan, abandonment of rice fields has rapidly increased, resulting in biodiversity loss. Fallow field biotopes are attractive measures for compensating wetland species habitats in paddy environments. However, effective management practices of fallow field biotopes for biodiversity conservation are largely unknown, especially for lentic aquatic insects (Odonata, Hemiptera, and Coleoptera). We conducted field experiments in abandoned rice terraces in western Hyogo Prefecture, central Japan. We plowed and flooded nine abandoned paddy fields and divided them into three types: paddy fields, biotopes, and mixed fields. We also surveyed irrigation ponds. To assess the function of the four habitat types, we examined how species richness, abundance, and community composition of aquatic insects differed among habitat types. Aquatic insect assemblages in biotopes differed from paddy fields and ponds and resembled that in a mixed field. The effects of environmental factors on the abundance and species richness of aquatic insects differ according to their order or life stages. The abundance of aquatic insects increased with surface area. The abundance of Odonata nymphs increased with water depth, whereas that of Hemiptera nymphs and Coleoptera larvae decreased. The abundance of Odonata nymphs and Hemiptera adults increased with increasing vegetation cover, whereas the species richness of aquatic insects decreased. Thus, it is important to prevent high vegetation cover by plowing and create a water depth gradient for creating habitats for multiple taxa. We suggest that creating or maintaining mosaic habitats, including paddy fields, biotopes, and ponds could enhance aquatic insect diversity in abandoned rice terraces.

Wetlands, integral constituents of natural ecosystems, play a pivotal role in bolstering biodiversity and providing habitats. Diminished lake expanses, degradation of wetlands, and pollution in arid and semi-arid regions present threats to the structural and functional aspects of wetland ecosystems. This study employed plant functional traits to assess changes in the functional composition of plant communities in lakeshore wetland ecosystems in the arid and semi-arid regions of the Mongolian Plateau in northern China, as well as to explore the effects of climatic and soil heterogeneity gradients on wetland ecosystem function. Our findings reveal that all trait metrics can be categorized into three primary trait groups: plant nutrient traits, plant structural traits, and plant energy acquisition traits. Environmental heterogeneity drove variations in plant functional traits across different spatial scales. Soil and climatic factors combine to explain variation in wetland plant community characteristics and functional diversity, with soil moisture content as a key factor influencing functional diversity. In some lake lakeshore region habitats that were seasonally waterlogged for an extended period, seasonal precipitation might impact plant structural traits. The functioning of the ecosystem is predominantly shaped by community structural traits, functional diversity, and soil factors. This study extensively examines the interplay among the functional traits, functional structure, and ecosystem function within lakeshore plant communities. This exploration holds paramount significance in establishing a scientific foundation for the restoration and reconstruction of wetland ecosystem vegetation in the lakeshore regions.

The enormous soil carbon pool stored by mangroves depends upon microbial respiratory activities and enzymes associated with carbon breakdown in soils. Our hypothesis is that increased microbial activity leads to elevated carbon breakdown. To prove this, we measured microbial respiratory and enzyme activity for nitrogen, phosphorus, and carbon cycle in soil from three coastal ecosystems: mangroves, restinga, and Atlantic forest. The multivariate ordination analysis showed that each treatment had distinct soil microbial activity according to the soil layer and seasons. Our results suggest that the Atlantic forest ecosystem had the highest respiration activity (i.e., CO₂-C release), dehydrogenase, phosphatase, protease, and urease activities, while mangroves and sandy coastal plains (called restinga) had lower respiration and enzyme activity. Therefore, soil microbial respiratory activity variation was influenced by soil microbial activity in the most superficial layer in coastal soil ecosystems. The agreement between dehydrogenase activity and CO₂-C respiration measurements suggests that microbial activity is an efficient indicator of carbon breakdown. Our findings also indicate that the vegetation type in the different ecosystems contribute to stimulate the soil microbiota increasing both its microbial activity and carbon storage. These issues should be considered for the conservation policies to promote effective protection of vital coastal ecosystems in Brazil. Understanding the coastal ecosystem-induced nutrient shifts in microbial communities is important because they can lead to lagged and multiplicative effects on carbon storage. Taken together, our results illustrate the identification of keystone (organic carbon and microbial activity) as an indicator to offer evidence-providing tools to achieve more ecologically efficient managing practices.

Graphical Abstract

Herbaceous isolated wetlands in the North American Southeastern Coastal Plain are important breeding sites for many imperiled amphibians. However, most are degraded from alterations to historic fire disturbance and hydrologic regimes. Without fire, encroaching woody vegetation can transition wetlands to more terrestrial conditions and negatively impact amphibian breeding habitat, yet few studies have experimentally tested the efficacy, cost, or temporal requirement of current methods to restore herbaceous wetland vegetation. Here, we tested the interaction of manipulating wetland canopy and leaf litter/duff to promote herbaceous vegetation within one year (i.e., one breeding season) in degraded herbaceous wetlands in South Carolina. We assessed plant response via herbaceous cover, composition, and species similarity to the wetland seed bank and then related treatment performance to treatment cost. Removing trees combined with burning, disturbing, or removing duff significantly increased herbaceous cover and proportions of wetland plants and graminoids. Removing trees alone did not improve herbaceous cover compared to closed-canopy controls, and manipulating duff alone had limited positive effects on plant cover and composition. The most expensive yet effective treatment was Tree Removal-Duff Removal, while Tree Removal-Duff Disturbance was the most cost-effective. At a minimum, we recommend removing trees and burning to kickstart herbaceous recovery. Promisingly, comparisons of our data with previous seed bank studies from these same wetlands indicate there was limited seed bank attrition during 30 years of woody encroachment. Results from this study should aid practitioners in choosing wetland restoration techniques to better conserve at-risk species in the Southeastern Coastal Plain.