Function Of Coastal Wetlands Research Articles

Consumer impacts on ecosystem functions in coastal wetlands: The data gap

AbstractOver the last 30 yr, our understanding of the factors that control the structure and function of coastal wetlands has shifted from a narrative that focused on bottom‐up control to one that explicitly includes top‐down factors. However, the emphasis of this transition has been on how consumers influence wetland vegetation; comparatively, few studies evaluate how consumers influence broader ecosystem properties and functions such as nutrient cycling and decomposition while fewer still investigate how trophic interactions affect these relationships. Here, we review the literature on consumer impacts on coastal wetland ecosystems and highlight areas where additional studies are sorely needed. It is our hope that identifying the current gaps in our knowledge will provide additional impetus for the study of community and ecosystem ecology within these globally important ecosystems.

Impacts of coseismic uplift caused by the 2010 8.8 Mw earthquake on the macrobenthic community of the Tubul-Raqui Saltmarsh (Chile)

Coseismic uplift, as caused by high-magnitude earthquakes, can modify shoreline morphologies and the functioning of coastal wetlands. This phenomenon occurred with the 8.8-Richter scale earthquake that affected central-south Chile in 2010. The recorded coseismic uplift was 1.6 m.a.s.l. significantly changed the Tubul-Raqui Saltmarsh. The most important impact of this event was decreased marine intrusion, which, in turn, led to desiccation within the saltmarsh and, consequently, the death of aquatic organisms. This study recorded the effects that physical/chemical changes in water quality and the sedimentary environment had on the macrobenthic community (>500 μm) 2, 6, and 10 months after the uplift event, with data compared against historical records. Non-metric multidimensional scaling evaluated changes in the biological community, while principal components analysis was used to assess environmental changes. Both matrices were adjusted through correlation. Significant pre-versus post-earthquake modifications were found at sites closest to the estuary inlet. The most significantly affected macroinvertebrate was Paracorophium hartmannorum. The most tolerant taxa to environmental perturbations (i.e., Diptera, Annelid, and Polychaeta) surpassed pre-earthquake abundance records after just ten months, whereas the most sensitive taxa were not found after the earthquake. Most (81.8%) variables of water quality (i.e., total suspended/inorganic/organic solids and chlorophyll-a), as well as the sedimentary environment (i.e., sediment redox potential, fine fraction, and area of emerged bed), were significantly correlated with the macrobenthic community. The results of this study show the resilience capacity of important components of a saltmarsh after a major natural disturbance.

Historical Evolution of Mariculture in China During Past 40 Years and Its Impacts on Eco-environment

The rapid development of mariculture in China in recent decades has satisfied people’s demand of seafood, and has made a great contribution to economic development. However, mariculture has also caused some negative impacts on the eco-environment. By statistically analyzing national data (as well as data for four main provinces) regarding the mariculture area and cultivation species in China since reform and opening up, the historical evolution of mariculture during the past 40 years was analyzed, the driving factors related to policy, market and technology innovation were discussed, and the potential impacts of mariculture on the coastal eco-environment were also illustrated. The statistical results indicated that the maricultural area increased radically during the past 40 years, from 1979 (116.47 × 103 ha) to 2012 (2205.65 × 103 ha), with an increase of nearly 20-fold. Shandong Province represented the fastest-growing region, with an increase of 31-fold. Moreover, the cultivated species had gradually become diversified. Initially, shellfish and algae were major species, and then it developed to various species including fish, and currently shellfish and crustaceans were the major species. The development of mariculture was driven by government policies, market economy and technology innovation. Rapid development of mariculture also caused significantly adverse impacts on the eco-environment of the coastal regions. For example, the sea reclamation for mariculture decreased the area and function of coastal wetlands and the contaminants originating from mariculture destroyed the coastal aquatic environment. Fortunately, the implementation of ‘13th Five-Year Fisheries Planning’ is expected to help both improve the seafood quality and reduce the contamination in coastal aquatic environment. This current study will provide reference for management and structure adjustment of mariculture in the future.

Analysis of Coastal Wetland Changes Using the “DPSIR” Model: A Case Study in Xiamen, China

Over the past several decades, human activities have had significant impacts on coastal wetlands worldwide. Here, using a model of “Drivers-Pressures-State-Impacts-Responses (DPSIR)” and data collected from coastal wetlands in Xiamen, China, we have analyzed temporal changes in regional coastal wetland ecosystem structure and function from 1950 through 2005. The study period was divided into four parts for comparative analysis: pre-1980s, 1980s, 1990s, and 2000 to present. Our results show that anthropogenic drivers of coastal wetland degradation in this region have increased substantially since 1950, and that this is correlated with a decline in coastal wetland function over the same period.

Impact of urbanization on coastal wetland structure and function

Abstract Urbanization is a major cause of loss of coastal wetlands. Urbanization also exerts significant influences on the structure and function of coastal wetlands, mainly through modifying the hydrological and sedimentation regimes, and the dynamics of nutrients and chemical pollutants. Natural coastal wetlands are characterized by a hydrological regime comprising concentrated flow to estuarine and coastal areas during flood events, and diffused discharge into groundwater and waterways during the non‐flood periods. Urbanization, through increasing the amount of impervious areas in the catchment, results in a replacement of this regime by concentrating rain run‐off. Quality of run‐off is also modified in urban areas, as loadings of sediment, nutrients and pollutants are increased in urban areas. While the effects of such modifications on the biota and the physical environment have been relatively well studied, there is to date little information on their impact at the ecosystem level. Methodological issues, such as a lack of sufficient replication at the whole‐habitat level, the lack of suitable indices of urbanization and tools for assessing hydrological connectivity, have to be overcome to allow the effects of urbanization to be assessed at the ecosystem level. A functional model is presented to demonstrate the impact of urbanization on coastal wetland structure and function.

Characterizing Seiche and Tide-driven Daily Water Level Fluctuations Affecting Coastal Ecosystems of the Great Lakes

Seiches in the Great Lakes probably play a role similar to that of tides in estuaries in organizing the structure and function of coastal wetlands and embayments, but information needed to test this idea is lacking. Past Great Lakes work has focused on enumerating frequencies of oscillation but without addressing their combined influence. Information on seiche magnitude is sparse and focused on extremes rather than typical levels, and tools that integrate magnitude and frequency components to derive net day-scale effects are lacking. This study uses water level time series to characterize daily fluctuation regimes for 51 stations around the Great Lakes. Distributions of fluctuation magnitude typically had long upper tails, with some level of activity always present. Logarithmic mean daily water level range varied from ∼4 cm in Lake Ontario to > 20 cm in Lake Erie, with largest values at the ends of lakes and in large bays. Oscillation frequency patterns were spatially variable and had both seiche and tide components. One-half the daily sum of water level increments is a computationally tractable metric of fluctuation intensity that integrates magnitude and frequency. This metric is directly interpretable as the column of water moved by all seiche and tide modes combined, which when multiplied by an area of interest yields the volume of water involved. Logarithmic mean values for this metric ranged from ∼10 cm in Lake Ontario to > 50 cm in Lake Erie. Data and tools provided will support future efforts to establish seiche and tide influences on Great Lakes wetlands and embayments.