Wetlands最新文献

Long-term data sets documenting temporal changes in vegetation communities are uncommon, yet imperative for understanding trends and triggering potential conservation management interventions. For example, decreasing species diversity and increasing non-native species abundance may be indicative of decreasing community stability. We explored long-term plant community change over a 40-year period through the contribution of data collected in 2019 to two historical datasets collected in 1979 and 1999 to evaluate decadal changes in plant community biodiversity in a tidal freshwater marsh in the Fraser River Estuary in British Columbia, Canada. We found that plant assemblages were characterized by similar indicator species, but most other indicator species changed, and that overall α-diversity decreased while β-diversity increased. Further, we found evidence for plant assemblage homogenization through the increased abundance of invasive species such as yellow flag iris (Iris pseudacorus), and reed canary grass (Phalaris arundinacea). These observations may inform concepts of habitat stability in the absence of direct anthropogenic disturbance, and corroborate globally observed trends of native species loss and non-native species encroachment. Our results indicate that within the Fraser River Estuary, active threat management may be necessary in areas of conservation concern in order to prevent further native species biodiversity loss.

Coastal wetlands are crucial ecosystems at the interface between land and sea. In the context of economic development and urbanization, these wetlands face challenges such as reduction in area and fragmentation. Ecological networks can connect fragmented habitats, creating corridors for material, information, and energy transmission. This is vital for maintaining biological and landscape diversity and ensuring the healthy development of ecosystems. However, there is currently no research on the ecological networks in the Hebei-Tianjin coastal wetlands. In this study, the morphological spatial pattern analysis method is employed to identify wetlands sources, while the minimum cumulative resistance model is used to extract potential ecological corridors. By combining these with existing river corridors, the ecological network of coastal wetlands in Hebei and Tianjin is constructed, and regional network characteristics are analyzed. Critical areas of ecological protection and restoration are determined, including important ecological corridors, ecological pinch points, and ecological breakpoints. The results showed that: (1) The ecological network of Hebei-Tianjin coastal wetlands consisted of 38 ecological sources, 171 potential ecological corridors, and 399 river corridors, with a total area of 851.31 km². (2) Key ecological protection and restoration areas were proposed, including 35 crucial potential wetlands ecological corridors, 343 ecological pinch points, and 99 ecological breakpoints. Targeted restoration of these critical areas could significantly improve the connectivity of wetlands ecological networks. (3) At present, priority should be given to protecting critical ecological corridors and existing river corridors with high similarity to potential ecological corridors. The findings of this study can provide a scientific basis for the network construction and protection of Hebei-Tianjin coastal wetlands.

The present systematic literature review (SLR) synthesized the literature on mangrove litterfall production and decomposition from studies published between 1985 and 2023 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Key questions about biophysical, chemical, and anthropogenic/societal factors influencing nutrient cycling via litterfall production and decomposition in mangrove forests were addressed. The SLR included 332 peer-reviewed original and review articles from the ScienceDirect, PubMed, and Google Scholar databases. The United States of America had the highest relative count (RC, 31.32%), followed by Japan (8.79%) and Indonesia (8.24%), and the lowest RCs were found in Bangladesh, Kenya, Philippines, and Thailand. We showed the increasing trend on these topics and discussed the milestones to enhance our understanding of litterfall production and decomposition processes and inform future research endeavors in the context of climate change. A positive trajectory for understanding litterfall production and decomposition for effective decision-making and management strategies towards mangrove conservation and sustainable use is also discussed. Ten-year research prospects were also identified, including studies on impacts of pollution, habitat degradation, climate change, and other destructive human activities. The trend in studies about mangrove litterfall production and decomposition suggests the growing recognition of mangroves’ ecological and societal importance. Future advancements can be made to better understand the biophysical, chemical, and anthropogenic factors influencing litterfall production and decomposition through the identified future research directions. Finally, the findings of the present review are relevant to supporting effective conservation and management strategies for mangroves in a changing climate.

Emerging contaminants (EC) are the modern age chemicals that are new to the environment. It includes pharmaceuticals & personal care products (PPCPs), pesticides, hormones, artificial sweeteners, industrial chemicals, microplastics, newly discovered microbes and many other manmade chemicals. These chemicals are harmful and having negative impacts on human being and other life forms. Existing treatment systems are ineffective in treating the EC and the treated effluent act as source of pollution to the water bodies. Considering the requirement of new technologies that can remove EC, the Constructed wetlands (CWs) are getting popular and can be a valid option for the treatment of EC. In this context application of macrophytes in CW have increased the removal performance of constructed wetland system. Growing macrophytes in CW have augmented the removal of EC from these systems. In different studies macrophytes supported the removal process of EC in CW and a removal efficiency up to 97% was achieved. This review summarizes the direct and indirect roles of macrophytes in CW in the treatment of EC. Also, it evaluates the success of CW technology, in treating EC, its limitation, and future perspective. The direct role of macrophytes include precipitation on root surface, absorption, and degradation of EC by these plants. Growth of macrophytes in CWs facilitates the uptake EC by the absorption and detoxify them in their cell with the help of enzymatic and hormonal activity which supports the removal of EC in wetland system. Indirect impacts, which appear to be more significant than direct effects, include increased removal of EC through better rhizospheric microbial activity and exudate secretions, which enhances the removal by four times. Thus, this review emphasizes combined application of CW and aquatic macrophytes which augmented the performance of CW for the treatment of EC.

Graphical Abstract

Acreman et al. (Wetlands 42:63, 2022) reviewed evidence for ecological damage to the Doñana wetlands (UNESCO World Heritage Site [WHS] and Ramsar site), Spain, associated with intensification of groundwater use, particularly for agriculture. Acreman et al. presented a multistep methodology for evidence-based risk assessment that involves identification of conservation issues, and a systematic review of scientific evidence for ecological damage and its causes. However, they involved few local scientists, used a questionable methodology in stakeholder selection and involvement, used a flawed conceptual framework, and an incomplete literature review. We propose improvements to their methodology. They overlooked or misinterpreted key evidence, and underestimated the impacts that abstraction for irrigation for red fruits (mainly strawberries), rice and other crops has had on Doñana and its biodiversity. They reported groundwater level depletion of up to 10 m in the deep aquifer, but wrongly concluded that there is no evidence for impacts on the natural marsh ecosystem, the dune ponds or the ecotone. Groundwater drawdowns are actually up to 20 m, and have inverted the formerly ascending vertical hydraulic gradient in discharge areas. Phreatic levels have been lowered from 0.5 to 2 m in some areas. Groundwater abstraction has caused multiple ecological impacts to temporary ponds and marshes in the WHS, as well as to terrestrial vegetation, and should be urgently reduced. Furthermore, Acreman et al. focused on groundwater quantity while overlooking the importance of severe impacts on quality of both surface and groundwater, intimately connected to the use of agrochemicals for irrigated crops.

The Nagoya Daruma pond frog Pelophylax porosus brevipodus (formerly Rana porosa brevipoda) requires a wet environment year-round, but such habitats have generally been lost due to improved rice paddy drainage such that the frog populations have been decreasing. There have been attempts to create permanent pools in rice paddy areas to help the populations recover, but the basic life history patterns and population dynamics in both environments have not been well studied. We captured frogs in rice paddies and adjacent biotopes. Using capture–mark–recapture data with 816 marked individuals, we compared frog demographics and population structure using a Jolly–Seber POPAN model. Constructed biotopes had conditions favoring long-term persistence. For example, biotopes had larger frogs of both sexes than rice paddies. The ratio of juveniles to adults was lower in biotopes than rice paddies. By contrast, rice paddies were an important habitat for breeding and producing new frogs. The two habitats complemented each other to support the local frog population. Because P. p. brevipodus is now exclusively distributed in rice paddy areas, the creation of permanent pools is a feasible way to improve habitat quality, especially in modernized rice paddy areas with few permanent lentic habitats.

Abstract

Wetland management practices often alter habitat characteristics to improve the function of the wetland (e.g., removing emergent vegetation for aesthetics or dredging for fish stocking), potentially at the cost of reducing habitat quality for wetland-dependent species such as freshwater turtles. We identified wetland and surrounding landscape characteristics related to painted turtle (Chrysemys picta) and snapping turtle (Chelydra serpentina) relative abundance and snapping turtle movement among wetlands. We surveyed turtles at 29 wetland sites (0.04–1.71 ha) in a mixed-use watershed in north-central West Virginia, USA, where hardwood forests and wetlands have been heavily fragmented by agriculture and roads. We also applied radio transmitters to 33 adult snapping turtles (17 females and 16 males) across 17 wetlands. Snapping turtle relative abundance was best estimated with mean substrate depth, mean wetland depth, and minimum distance from roads. Painted turtle relative abundance was best estimated with the null model. We documented movement among wetlands for 22 snapping turtles (67%), including 10 females and 12 males. The probability of inter-wetland movement decreased with increased minimum distance from wetlands. Our results suggest that the focal turtle species readily used shallow, mucky wetlands with deep substrate and that increasing the density of wetlands could increase snapping turtle population connectivity. Managers could consider restoring a diversity of wetland types that result in reduced travel distance between wetlands and that collectively have characteristics conducive to multiple species.

Abstract

Fish can act as dispersal vectors for many plant species, and this mutualistic relationship is critical for structuring and regeneration in Amazonian floodable forests. However, anthropogenic threats, such as the deforestation of floodable forests and the overfishing of some species, can disrupt this mutualistic interaction. We investigated the relationship between the size of fish that consume fruits and seeds and the size of seeds retrieved from the fish in the floodable forests. We hypothesize that, in floodable forests, fish with larger body size disperse the larger seeds. A total of 1,054 seeds from 16 plant species were found in the digestive tracts of nine species of frugivorous fish. The length and weight of the fish were positively related with the size of the seeds found in the digestive tracts. The reduction in fish abundance and size may affect dispersal and regeneration, especially of species with larger seeds. Considering the diverse threats to interactions between fish and Amazonian forested wetlands, our study highlights the importance of adequate management of fishery resources and floodable forests for the maintenance of ecosystem services of these environments in the region.

Abstract

The hydroperiod (i.e., the length of time ponded water is present) of prairie potholes is sensitive to climate change. Because snowmelt runoff is the largest contributor to ponded water amounts, a seasonal change in precipitation timing, even when annual amounts are unchanged, can affect wetland hydroperiod. We observed a change in precipitation timing in the Alberta Prairie Pothole Region from 2014 to 2015, though cumulative precipitation amounts were near equivalent. We sought to understand whether this change in precipitation timing could result in (1) a decline in wetland hydroperiod and (2) a change in the community composition of birds, aquatic macroinvertebrates, and plants. Our findings suggest a change in precipitation timing occurred in 2015 (i.e., delayed-precipitation year), which could be tied to a decline in wetland hydroperiod. Wetlands in the delayed-precipitation year were dominated by upland birds and drought-adapted aquatic macroinvertebrates. There was no change in the community composition of plants, and we hypothesize that this may be explained by their ability to use energy stored from the previous year to survive this one-year change in their growing season. We suspect that consecutive declines in hydroperiod year-to-year could shift vegetation communities to being dominated by wet meadow or terrestrial plants; this will ultimately lead to a further reduction of waterbird habitat in the northern PPR – the last refuge for this guild in the PPR.

Common carp (Cyprinus carpio) is an invasive fish species in North America and around the world. Through their feeding and spawning they contribute to the deterioration of wetland habitats. Exclusion structures are a frequently used management option for limiting their negative impacts. While habitat responses to common carp exclusion have been reported, little is known about impacts of exclusion structure operation on native fish assemblages. Here we describe a common carp exclusion project on a large freshwater coastal wetland, Delta Marsh, in south-central Manitoba, Canada. Most fish species, including common carp, overwinter in Lake Manitoba and migrate each spring to feed and spawn in the marsh. Exclusion structures with removeable screens were installed on connecting channels between the lake and marsh and were deemed the best management option to exclude common carp from the marsh. In this paper we contrast relative abundance and mean size of large-bodied fish species between pre- (three years) and post- (six years) exclusion periods, as well as inside and outside the common carp exclusion zone. In addition, we monitored fish migration into the marsh to evaluate initial management recommendations. Using a combination of delayed exclusion screen placement and 70 mm screen openings, we were able to reduce the number of large common carp present in the marsh with minimal impacts on the native fish assemblage. We also provide suggested changes to the timing of screen placement to increase common carp exclusion.