Ecological restoration system suitable for coastal abandoned fishpond

Abstract

The utility model provides an ecological restoration system suitable for a coastal abandoned fishpond, which designs four key areas: an ecological barrier buffer area close to the inland, and the influence of human activities can be effectively reduced through a vegetation barrier; secondly, a salt marsh wetland habitat area close to the ocean is provided with a salt marsh beach land and a primary tidal creek connected with the ocean; the tidal conservation area is located between the ecological barrier buffer area and the salt marsh wetland habitat area, and a shoal wetland surrounded by a water body is arranged; a composite habitat lifting area is bordered with the shoal wetland and provided with a salt marsh wetland and a bird inhabiting island higher than the wetland, and plants suitable for birds to inhabit and find food are planted on the shoal wetland, the salt marsh wetland and the bird inhabiting island. The wetland and the bird inhabiting island are surrounded by water and are communicated with the ocean through the first-stage tidal creek, so that natural circulation and ecological connectivity of the water are guaranteed. The ecological restoration system is suitable for restoring the abandoned fishpond in the coastal area, and the biological diversity of the coastal wetland can be remarkably enhanced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the ecological restoration engineering field, concretely relates to an ecological restoration system suitable for coastal abandoned fishpond. BACKGROUND

[0002] After the coastal wetland is artificially transformed into a fishpond, its original wetland characteristics will be severely damaged. With the abandonment of these fishponds, the wetland is facing the risk of degradation, and this recession not only constitutes a threat to the sustainability of biological diversity, but also causes damage to the ecological environment and economic development of our surrounding areas. According to the analysis, it is found that the abandoned fishpond and its adjacent coastal wetland generally have problems such as habitat isolation, invasion of alien species, and interruption of hydrological cycle. Traditional abandoned fishpond restoration measures are often limited to simple transformation of the terrain, and this single approach is far from enough to rebuild a sustainable and stable ecological system. In view of this, there is an urgent need for a comprehensive ecological restoration system to effectively restore the ecological function of the coastal wetland and make it regain vitality. SUMMARY

[0003] In view of the problems of wetland characteristics and biological diversity degradation faced by the current coastal abandoned fishpond, as well as the problem that the traditional terrain transformation method cannot achieve stable and sustainable ecological development demand, the utility model provides an ecological restoration system suitable for coastal abandoned fishpond. The ecological restoration system plans four regions, including: an ecological barrier buffer zone adjacent to the inland, which effectively isolates human activities from disturbance by using vegetation; a salt marsh wetland habitat zone adjacent to the sea, which is arranged with a salt marsh wetland beach and a tidal ditch directly reaching the ocean; a tidal habitat conservation zone located between the ecological barrier buffer zone and the salt marsh wetland habitat zone, which is arranged with a shallow wetland surrounded by water, and a complex habitat improvement zone adjacent to it is arranged with a salt marsh wetland and a bird habitat island higher than the wetland. These regions are planted with vegetation suitable for bird habitat and foraging. The wetland and bird habitat island in the entire region are surrounded by water and connected to the ocean through a first-order tidal ditch, ensuring the natural flow and ecological connectivity of the water body. The ecological restoration system is suitable for the ecological restoration of coastal abandoned fishponds, can improve the biodiversity of coastal wetlands, and thus builds a stable and prosperous ecological system.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] An ecological restoration system suitable for abandoned fish ponds near the sea, comprising: an ecological barrier buffer zone arranged near the inland side for planting vegetation to shield human activities; a salt marsh habitat zone arranged near the sea side, comprising a salt marsh beach, and a plurality of primary tidal ditches penetrating through the salt marsh beach and communicating with the sea; a tidal habitat conservation zone arranged between the ecological barrier buffer zone and the salt marsh habitat zone, provided with a shallow beach wetland surrounded by water; a composite habitat enhancement zone arranged between the ecological barrier buffer zone and the salt marsh habitat zone, provided with a salt marsh wetland surrounded by water and a bird habitat island; the salt marsh wetland, the shallow beach wetland and the bird habitat island are all planted with vegetation for birds to inhabit and forage; the water surrounding the shallow beach wetland, the salt marsh wetland and the bird habitat island is communicated with the sea through the primary tidal ditch.

[0006] In some embodiments, the composite habitat enhancement zone is further provided with a plurality of transverse tidal ditches and longitudinal tidal ditches, the transverse tidal ditches and the longitudinal tidal ditches separate the salt marsh wetland into a plurality of units, and the transverse tidal ditches and the longitudinal tidal ditches are communicated with the water surrounding the salt marsh wetland.

[0007] In some embodiments, in the composite habitat enhancement zone, the water surface elevation of the water surrounding the salt marsh wetland and the bird habitat island is greater than or equal to 4.3m, and the bottom elevation is greater than or equal to 3.5m; the salt marsh wetland is at least partially above the water surface, with a height difference greater than or equal to 0.2m; the bird habitat island is at least partially above the water surface, with a height difference greater than or equal to 1m.

[0008] In some embodiments, the composite habitat enhancement zone is further provided with an ecological beach arranged around the bird habitat island, and salt-tolerant plants are planted on at least part of the bird habitat island and the ecological beach.

[0009] In some embodiments, the tidal habitat conservation zone is further provided with a plurality of transverse tidal ditches and longitudinal tidal ditches, the transverse tidal ditches and the longitudinal tidal ditches separate the shallow beach wetland into a plurality of units, and the transverse tidal ditches and the longitudinal tidal ditches are communicated with the water.

[0010] In some embodiments, the tidal habitat conservation zone is further provided with a plurality of water ponds and hydrological communication ditches, the water ponds are communicated with the primary tidal ditches and the water surrounding the shallow beach wetland through the hydrological communication ditches; adjacent water ponds are communicated through the hydrological communication ditches.

[0011] In some embodiments, the salt marsh habitat zone further comprises: a plurality of secondary tidal ditches, the secondary tidal ditches separate the salt marsh beach into a plurality of units, and the secondary tidal ditches are communicated with the primary tidal ditches; the width of the secondary tidal ditches is less than the width of the primary tidal ditches.

[0012] In some embodiments, the salt marsh habitat zone further comprises a number of hydrologically connected pipes for connecting the primary tidal creek and the ocean.

[0013] In some embodiments, the salt marsh habitat zone is further provided with a carbon flux tower for measuring the carbon dioxide exchange between the atmosphere and the ecological restoration system.

[0014] In some embodiments, the vegetation is one or more of reed, water candle, sea three prong rush, rush, salsify, sea thrift, rough leaf carex, cogon grass, rhinoceros hair, pseudo- rush, and sweet clover; and / or, the ecological restoration system further comprises benthic organisms and aquatic organisms disposed within the water body surrounding the shallow wetland, the salt marsh wetland, and the bird habitat island.

[0015] Compared with the prior art, the ecological restoration system has the following beneficial effects:

[0016] 1. The ecological restoration system provided by the utility model reduces human influence by setting an ecological barrier buffer zone on the inland side, sets a salt marsh habitat zone near the ocean side, arranges a primary tidal creek connected with the ocean; the tidal conservation zone is provided with a shallow wetland, the adjacent composite habitat promotion zone is provided with a salt marsh wetland and a bird habitat island, the wetlands and the island are all planted with vegetation suitable for bird habitat, the wetlands and the island are all surrounded by water bodies and connected with the ocean through the primary tidal creek, ensuring the ecological connectivity between the wetlands and the ocean. Moreover, the utility model creates diversified habitats including the salt marsh wetland, the shallow wetland and the bird habitat island, provides habitats and breeding places for different species, thereby increasing the biodiversity.

[0017] 2. The utility model arranges the longitudinal and horizontal crisscross tidal creeks and tidal ditches in the composite habitat promotion zone and the tidal conservation zone respectively, divides the shallow wetland and the salt marsh wetland into a plurality of ecological units, the waterway network ensures the smooth exchange between the water bodies, promotes the uniform distribution and circulation of nutrients. In addition, the unitized layout also forms a rich and varied micro-ecological environment, provides suitable habitats for various benthic and aquatic organisms, significantly improves the species diversity. At the same time, the tidal creeks also provide convenient migration paths for organisms between the units of the wetland, strengthen the overall connectivity of the ecological system, and promote the flow of species. BRIEF DESCRIPTION OF DRAWINGS

[0018] The utility model will be further described below in combination with the drawings and examples.

[0019] Figure 1 The regional distribution diagram of the ecological restoration system provided by the utility model example 1 is shown in the figure.

[0020] Figure 2 This is a schematic diagram of the structure of the ecological restoration system provided in Embodiment 1 of this utility model.

[0021] The meanings of the symbols in the attached diagram are as follows:

[0022] 1—Primary tidal channel; 2—Salt marsh wetland surface; 3—Secondary tidal channel; 4—Hydrological connecting pipe; 5—Shallow wetland; 6—Hydrological connecting ditch; 7—Pond; 8—Salt marsh wetland; 9—Bird habitat island; 10—Ecological beach. Detailed Implementation

[0023] The present invention will be further explained in detail below with reference to the accompanying drawings and specific embodiments. However, the following description of the embodiments is only intended to enable those skilled in the art to better understand the principles and essence of the present invention, and does not imply any limitation on the present invention.

[0024] Combination Figure 1 and Figure 2 As shown, this embodiment provides an ecological restoration system suitable for abandoned coastal fishponds. The system divides the abandoned coastal fishponds requiring ecological restoration into four zones: an ecological barrier buffer zone, a salt marsh wetland habitat zone, a tidal habitat conservation zone, and a composite habitat enhancement zone. Specifically:

[0025] The ecological barrier buffer zone is set up on the inland side. By carefully selecting and cultivating diverse vegetation, an ecological isolation barrier is constructed to effectively shield and reduce the disturbance of human activities to the ecosystem, and to ensure the stability of the entire ecological restoration system and the continuity of natural ecological processes.

[0026] The salt marsh wetland habitat area is located on the side close to the ocean, including the salt marsh wetland beach 2 and several primary tidal channels 1 that run through the salt marsh wetland beach 2 and connect with the ocean.

[0027] The tidal habitat conservation area is located between the ecological barrier buffer zone and the salt marsh wetland habitat area, and includes 5 shallow wetlands surrounded by water.

[0028] The composite habitat enhancement zone is located between the ecological barrier buffer zone and the salt marsh wetland habitat zone. It includes a salt marsh wetland 8 surrounded by water and a bird habitat island 9. The elevation of the bird habitat island 9 is greater than that of the salt marsh wetland 8.

[0029] The salt marsh wetland 8, the shoal wetland 5 and the bird habitat island 9 are planted with vegetation for birds to inhabit and forage, and the water surrounding the shoal wetland 5, the salt marsh wetland 8 and the bird habitat island 9 is connected with the sea through the primary tidal ditch 1. The primary tidal ditch 1 as a water flow channel helps the ebb and flow of tidal water, maintains the water circulation of the salt marsh wetland 8, the shoal wetland 5 and the bird habitat island 9, reduces water accumulation, prevents oxygen deficiency caused by water accumulation inside, and can also transport nutrient salts and organic matter in seawater to provide nutrients for the entire ecosystem, promote plant growth, and promote the reproduction of benthic organisms and aquatic organisms.

[0030] In some embodiments, some benthic organisms and aquatic organisms are introduced into the complex habitat enhancement area, which can live in the water surrounding the salt marsh wetland 8 and the bird habitat island 9, adding species diversity, and these organisms are also a food source for birds, promoting the prosperity and balance of the entire region.

[0031] Further, the complex habitat enhancement area is provided with a plurality of transverse tidal ditches and longitudinal tidal ditches, which separate the salt marsh wetland 8 into a plurality of units and are connected with the water surrounding the salt marsh wetland 8. The tidal ditch network formed by the transverse tidal ditches and the longitudinal tidal ditches separates the salt marsh wetland 8 into a plurality of small units, increases the connectivity between the inside and outside of the salt marsh wetland 8, and helps the migration and gene flow of organisms in the habitat enhancement area, maintaining the survival and reproduction of species. The transverse tidal ditches and the longitudinal tidal ditches also help to regulate water flow, so that water can be more evenly distributed between the various wetland units, reducing the possibility of water accumulation or drought in some areas.

[0032] The depth of the transverse tidal ditches and the longitudinal tidal ditches satisfies the water connection function, and is preferably 0.1 m.

[0033] Further, the water surrounding the bird habitat island 9 in the complex habitat enhancement area is set as a deep water area, with a water surface elevation greater than or equal to 4.3 m and a bottom elevation greater than or equal to 3.5 m.

[0034] The elevation of the salt marsh wetland 8 is 4.5, and the salt marsh wetland 8 is at least partially higher than the water surface, with a height difference greater than or equal to 0.2 m, i.e. the height difference between the part of the salt marsh wetland 8 above the water surface and the water surface is greater than or equal to 0.2 m.

[0035] The bird habitat island 9 is at least partially higher than the water surface, with a height difference greater than or equal to 1 m, and the part of the bird habitat island 9 above the water surface is an ecological island for birds to inhabit, and the part below the water surface forms a habitat space for aquatic organisms and benthic organisms.

[0036] Further, the composite habitat promotion area is also provided with ecological beaches 10 arranged around the bird habitat island 9, the ecological beaches 10 can be used as a buffer zone between the bird habitat island 9 and the water body, so as to reduce the direct impact of sea water fluctuation caused by tides on the bird habitat island 9, and provide a safe habitat for the birds.

[0037] The highest elevation of the gentle slope part of the ecological beach 10 is 4.5 m, salt-tolerant marsh plants such as reeds and water candles are planted on a part of the bird habitat island 9 and the ecological beach 10, and another part is bare. Due to the rise and fall of tides, the silt in the sea water will be carried to the beach surface which is not covered by vegetation, and as the tide recedes, the silt will be deposited, gradually forming a mud beach. In this process, a large amount of organic matter, inorganic nutrients, algae, microorganisms and other substances carried by seawater will also be deposited on the mud beach, providing a rich food source for benthic organisms.

[0038] After comprehensively considering the characteristics of different birds, the vegetation types in the composite habitat area are reasonably arranged to realize the harmonious coexistence of ecological diversity and biological diversity. For example, around the bird habitat island 9, ecological beaches 10 such as pebble shoals are constructed, and in the area above the high water level, tree forests are planted for birds to inhabit, and in the waterfront area, dense reed and other herbaceous plants are planted for wading birds to hide and forage. Wading birds are alert and easy to be frightened, so human disturbance is strictly prohibited in their habitat.

[0039] For swimming birds, salt-tolerant plants are planted on the bird habitat island 9 to facilitate the habitat and nest building of swimming birds. At the same time, small fish and shrimps are raised in the water around the island to provide sufficient food resources for swimming birds. Considering that swimming birds such as blue-headed diving ducks are extremely sensitive to human activities, enough open water is reserved to ensure that they can swim and forage freely without human disturbance.

[0040] For singing birds, reeds, sea arrowhead and other marsh herbaceous plants are planted to provide a wide nesting and resting area for them.

[0041] The composite habitat promotion area proposed in the utility model ingeniously arranges the bird habitat island 9 in the center of the water body, aiming to minimize the potential impact of human activities on the bird habitat, so as to provide an undisturbed habitat for the birds.

[0042] In some embodiments, the tidal habitat conservation area described above further comprises a plurality of transverse tidal ditches and longitudinal tidal ditches, which divide the shallow wetland 5 into a plurality of units and are in communication with the water body. The transverse and longitudinal tidal ditches have the same effect as the transverse and longitudinal tidal ditches in the complex habitat enhancement area, i.e., they divide the shallow wetland 5, improve the internal and external connectivity, facilitate the migration and exchange of organisms in the area, and maintain the reproduction of species. At the same time, the tidal ditches can regulate the water flow, balance the moisture of the wetland, and prevent flooding and drought.

[0043] Further, the tidal habitat conservation area further comprises a plurality of ponds 7 and hydrological communication ditches 6, the ponds 7 are in communication with the primary tidal ditch 1 and the water body surrounding the shallow wetland 5 through the hydrological communication ditches 6, and the adjacent ponds 7 are in communication through the hydrological communication ditches 6. The ponds 7 provide habitats for a variety of aquatic organisms, mainly including fish, amphibians, aquatic insects, etc., which are essential for maintaining the balance of the wetland ecosystem.

[0044] In addition, the ponds 7 also play an important role in water storage during tidal changes. They work together with the tidal ditches to effectively regulate the water level in the wetland, thereby reducing the negative impact of tidal fluctuations on the wetland ecology.

[0045] In some embodiments, the salt marsh wetland habitat area further comprises a plurality of secondary tidal ditches 3, which divide the salt marsh wetland surface 2 into a plurality of units and are in communication with the primary tidal ditch 1. The presence of the secondary tidal ditches 3 increases the connectivity of the water flow, helps to improve the water flow circulation in the wetland, promotes water renewal, and maintains water quality.

[0046] In addition, the secondary tidal ditches 3 can optimize the distribution of water resources in the salt marsh wetland 8, help to improve the productivity of the wetland, promote plant growth and biomass accumulation. Moreover, during tidal changes, the secondary tidal ditches 3 can help to regulate the water level of each unit, reduce the large water level fluctuations caused by a single tidal ditch, and provide a more stable living environment for benthic organisms and salt-tolerant plants.

[0047] Preferably, the width of the secondary tidal ditches 3 is smaller than the width of the primary tidal ditches 1.

[0048] Further, the salt marsh habitat area also includes: a plurality of hydrological connection pipes 4 for connecting the first tidal ditch 1 and the ocean. The first tidal ditch 1 and the second tidal ditch 3 inside the salt marsh beach are not directly connected to the outside seawater, which benefits from the barrier effect of the beach outside the wave dissipation dam. Under normal circumstances, seawater is effectively blocked and cannot enter the beach, and only when the tide rises, seawater can break through the line of defense and flow in. The hydrological connection pipe 4 is equivalent to creating a special channel on the wave dissipation dam, allowing seawater from the outside to flow into the first tidal ditch 1 through the pipe, and the water in the tidal ditch can flow with the rise and fall of the ocean tide, maintaining the natural hydrological cycle.

[0049] Further, a carbon flux tower is also provided in the salt marsh habitat area for measuring the carbon dioxide exchange between the atmosphere and the ecological restoration system. Ecological restoration is a long-term process, and the carbon flux tower can provide long-term continuous data to help monitor the long-term changes and stability of the wetland ecosystem.

[0050] In summary, the utility model adopts an ecological restoration strategy of "regional linkage and habitat connection". Through hydrological connection and micro-topography reconstruction technology, the coastal abandoned fish pond to be restored is divided into three functional areas: ecological barrier buffer zone, tidal habitat conservation area and composite habitat improvement area. Regional linkage emphasizes the interaction and coordination between different ecological regions, while habitat connection is achieved through the construction of the first tidal ditch 1, the second tidal ditch 3, the hydrological connection ditch 6 and the hydrological connection pipe 4, realizing the water system connection between shallow sea, beach, salt marsh and land, and promoting the harmonious linkage of land and marine ecosystems.

[0051] In some embodiments, the vegetation planted in the ecological barrier buffer zone, the salt marsh habitat area, the tidal habitat conservation area and the composite habitat improvement area is one or more of reed, sea three-prong rush, rush, scirpus, sea heather, rough leaf sedge, cogon grass, rhynchospora alba, pseudo-onychium, and melilot.

[0052] According to the growth habit of common beach plants and their adaptability to tidal flat salinity and elevation, 10 local or naturalized beach plants are roughly divided into three categories:

[0053] ① Adapted to low-tide beach and intertidal zone: reed, sea three-prong rush, rush.

[0054] ② Adapted to medium and high-tide beach: reed, scirpus, sea heather, rough leaf sedge, cogon grass.

[0055] ③ Adapted to higher beach and highland inside the coastal embankment: reed, scirpus, sea heather, rough leaf sedge, cogon grass, rhynchospora alba, pseudo-onychium, and melilot.

[0056] According to the topographic features and tidal flat salinity in different areas, suitable plants are selected for planting to ensure ecological adaptability and growth effect.

[0057] Example 2

[0058] On the basis of example 1, the utility model provides an example preferred implementation example:

[0059] There is a fish pond in a piece of salt marsh wetland 8 in the west side of Zhonggang in Fengxian District of Shanghai, which has been in a state of abandonment for a long time, and the utility model plans to carry out ecological restoration. After investigation, the background structure of the region is relatively stable, and there is no obvious change in the region. There is human activity in the local area, which occupies part of the tidal flat resources, and part of the area changes from salt marsh resources to pond 7, but the overall situation has no obvious change. If human disturbance is eliminated, the ecological function of the region can be further improved or improved after optimizing the present habitat structure.

[0060] The degree of fluctuation in the project area is not large, and it decreases slightly from south to north. The elevation of most areas is about 4.0m, and the overall elevation is 3.8-4.5m. The terrain inside the fish pond is flat, and the elevation is 3.5-3.6m. There is no obvious difference in the elevation of the beach in each fish pond. The surrounding of the pond 7 in this area is surrounded by a soil ridge, and the elevation of the soil ridge is about 4.8-5.5m.

[0061] According to the field investigation, it is found that there are four ecological problems in the region: (1) There are invasive species growing in the project area, such as Spartina alterniflora and Solidago canadensis; (2) The region is close to the levee, and the wetland is easily disturbed by human activities, and lacks ecological barriers; (3) Each pond 7 is divided into independent units by the dike, and the ecological conservation function needs to be improved; (4) The connectivity between the wetland and the outside sea area is poor, and the marine biological activity is hindered. According to relevant research, if the aquaculture pond 7 is left unattended for a long time and is not ecologically transformed, the natural succession of the abandoned pond 7 may affect biodiversity, such as a sharp decline in the number of water birds and a decrease in species diversity. Therefore, artificial management measures need to be taken to some extent to prevent drought and increase environmental heterogeneity.

[0062] Combined with the current situation of the region, the abandoned fish pond restoration area is divided into the following four areas:

[0063] (1) Ecological barrier buffer zone

[0064] This area mainly builds an ecological barrier for wetland organisms to reduce human activity disturbance. First, clean up the beach in this area, remove Solidago canadensis and illegal vegetable gardens, and remove crop products and household garbage left by human activities. The reed in the area is retained, and then the Hibiscus hamabo and other plants are planted in the area to form a vegetation belt with certain shading effect.

[0065] (2) Salt marsh wetland habitat area

[0066] The region is close to the sea, and first, the original tidal ditch through the salt marsh wetland beach 2 is repaired, and the sundries blocking the tidal ditch are removed, and the silt is dug out to expand its capacity. After several main tidal ditches are newly built, these ditches are the primary tidal ditches 1 mentioned in Example 1. At the same time, the original secondary tidal ditches on the beach, i.e., the secondary tidal ditches 3, are restored. According to the specific conditions of the salt marsh wetland beach 2, several secondary tidal ditches 3 are additionally newly built to further optimize the hydrological structure of the beach.

[0067] (3) Tidal habitat conservation area

[0068] The region is located between the ecological barrier buffer zone and the salt marsh habitat zone, and in this example, the tidal habitat conservation area is set on the west side of the abandoned fish pond, which is mainly optimized through hydrological connection and micro-topographic modification. In this example, the shallow wetland 5 in the region is divided into two parts. The shallow beach on the west side is connected to the outside seawater through the primary tidal ditch 1, and forms a habitat for wading birds together with the existing reed community in the region. The shallow beach on the east side is divided into several units through horizontal and vertical tidal ditches, and part of the beach is planted with reeds and alkali grass, and part of the beach forms bare beach. Aquatic animals and benthic animals are released into the water around the shallow beach to create a multi-habitat type bird feeding site in this region.

[0069] (4) Compound habitat improvement area

[0070] The region is located between the ecological barrier buffer zone and the salt marsh habitat zone, and in this example, the tidal habitat conservation area is set on the east side of the abandoned fish pond, and there is a salt marsh 8 surrounded by water and a bird habitat island 9 in the region. The salt marsh 8 is 0.2 m higher than the water surface, and the bird habitat island 9 is 1 m higher than the water surface. Plants are planted on the salt marsh 8 and the bird habitat island 9 to optimize the habitat, such as sea three-prong rush, reed, and salt marsh plant. A certain amount of benthic organisms and aquatic organisms are released into the water to attract birds into the ecological zone to prey, and the water below can be used as a habitat for aquatic organisms.

[0071] After the above-mentioned regions are delineated, the specific implementation content in each region is as follows:

[0072] (1) Beach arrangement:

[0073] The beach arrangement work is mainly aimed at the regions where Canada goldenrod and other plants are widely distributed within the project scope, and they are removed through mowing and plowing, and at the same time, human activity left-over garbage is removed to provide site conditions for planting.

[0074] In the ecological barrier buffer zone, first clean up the beach area, remove the Canada goldenrod and clean up the beach, and remove the human activity left over garbage. Retain the reed and shrubs in the area, plant the reed and sea mallow in the 5-6m elevation range, plant the salt-tolerant native trees such as sargentcottonwood, broussonetia papyrifera, etc. above 6m elevation, and form a certain sheltering vegetation belt.

[0075] (2) Vegetation restoration:

[0076] Retain and restore the original vegetation in the area, mainly including sea mallow, salt marsh vegetation and aquatic vegetation.

[0077] (3) Soil ridge removal and reconstruction

[0078] In order to overcome the obstruction of the original fish pond soil ridge to the natural flow of water, and eliminate the habitat segmentation problem caused by the soil ridge, the project implements the removal and reconstruction of the soil ridge in the project area.

[0079] The removal area is mainly located at: ① the connection between the original south soil ridge of the pond and the tidal ditch, hydrological communication ditch 6, after breaking, the pond loses the high water storage function and can communicate with the outside world; ② the north-south soil ridge in the middle of the pond, after removal, the water system of three areas is connected, and the habitat integration is realized. The remaining soil ridge is reconstructed, the surface is laid with stone, the structure of the beach is stabilized, and a convenient passage for maintenance personnel to patrol and maintain is formed.

[0080] Specific removal target: the soil ridge around the abandoned fish pond is removed to 800mm below the design top elevation, a layer of gravel cushion with a thickness of 200mm is laid, and stepping stones are arranged on it at intervals. The specification of the stepping stones is 1000mm x 900mm x 400mm, the top surface of the throwing stone is appropriately widened, a certain space is reserved for vegetation growth, and the triangular joint width is not greater than 15cm.

[0081] (3) Hydrological communication.

[0082] As shown in Figure 2 , the hydrological communication includes expanding the original tidal ditch, newly building a number of tidal ditches, newly building a hydrological communication ditch and a hydrological communication pipe 4. According to the calculation, the original tidal ditch cannot meet the required water exchange between the project area and the outside sea in each tidal period, so the main tidal ditch of the original tidal ditch system is expanded, a first tidal ditch 1 system and a hydrological communication pipe 4 are newly built in the salt marsh habitat area, several second tidal ditches 3 are arranged, a water pond 7 is newly built in the tidal habitat conservation area, and a hydrological communication ditch 6 is arranged to connect the water pond 7 with the surrounding water body, so as to realize the hydrological communication between the water body in the whole project area and the water body outside the sea.

[0083] The hydrological communication ditch 6 has a cross-sectional size of a bottom width of 4 m and a slope of no more than 1:2. The communication ditch is protected by dry masonry with a thickness of 350 mm, and a bagged gravel cushion layer with a thickness of 150 mm is laid under the masonry.

[0084] (4) Microtopography reconstruction

[0085] The microtopography reconstruction is mainly based on the present topography in the region and the habitat characteristics of the salt marsh ecosystem, and the earthwork balance is maintained during the microtopography reconstruction, and no additional earthwork is purchased.

[0086] According to the above-mentioned zoning, the east side of the project area is positioned as a composite habitat improvement area, the microtopography is created in combination with the topographic and geomorphic conditions of the region, the water surface elevation in the composite habitat improvement area is controlled to be 4.3 m, the water body bottom elevation is 3.5 m, the higher area is selected to dig a ditch and build an island, and the bird habitat island 9 with a natural undulating terrain and a relative elevation difference of 1.5-1.8 m is created. The bird island is a gentle slope, and the highest point is controlled to be 0.8-1.2 m away from the water surface. The water depth around the bird habitat island 9 is 0.2-0.3 m, which can provide feeding and activity places for wading birds.

[0087] A deep water ditch with a depth of about 2 m and a width of 15-20 m is created at a distance of 6-10 m from the bird habitat island 9, and a certain deep water area is designed to provide a refuge for fish in the dry season and provide feeding and activity places for wading birds.

[0088] And the salt marsh wetland 8 is built in the west side of the composite habitat improvement area, with an elevation of 4.5 m and a height of 0.2 m above the water surface. Reed and sea three-prong rush are planted on it. After microtopography reconstruction, it can create a habitat with certain heterogeneity for birds, and also provide different flooding time growth environment for salt marsh plants.

[0089] Combined with the hydrological connection of step (3), new transverse and longitudinal tidal ditches are built, and transverse and vertical tidal ditches are arranged in the salt marsh wetland 8. The depth of the tidal ditch is 0.1 m to meet the water connection function requirement and create conditions for feeding for birds and other waders.

[0090] It should be noted that when the earth ridge in the water body is reconstructed, the earth ridge is fixed by riprap to prevent the earth ridge from falling.

[0091] The ecological beach 10 is set around the bird habitat island 9 on the east side of the west side of the composite habitat improvement area. The beach has a gentle slope and the highest elevation is 4.5 m. Sea three-prong rush, reed and salt bush are planted on it. A sparse salt marsh is created on the beach surface to attract birds.

[0092] When constructing elevated beaches in the water bodies of composite habitat enhancement zones, some bottom sediment is modified for topography shaping. Given that organic matter, heavy metal pollutants, and pesticide residues in the bottom sediment of abandoned fishponds may negatively impact aquaculture activities, sediment modification treatment is essential before topography shaping. This aims to stabilize the sediment structure while supporting the growth of benthic organisms and plants. The leachate from the selected modification materials strictly complies with the national Class II surface water standard, ensuring environmental safety and ecological balance.

[0093] like Figure 2 As shown, two shallow wetlands 5, one in the east and one in the west, were created in the tidal habitat conservation area. The water level of the water body surrounding the shallow wetland 5 was controlled at 4.0m, and the elevation of the shallow wetland 5 itself was controlled at 4.3m. In conjunction with hydrological connectivity, transverse and longitudinal tidal channels were constructed. The surface of the eastern shallow wetland 5 was divided into several small units by several transverse and vertical tidal channels. The areas near the tidal channels around the small units were planted with *Scirpus triqueter*, while the interiors were planted with *Carex scabra* and *Suaeda salsa*, respectively, to increase habitat heterogeneity and attract birds and intertidal organisms.

[0094] Two interconnected ponds 7 are also arranged in the tidal habitat conservation area and connected by a hydrological connecting ditch 6. These two ponds 7 are not only connected to each other, but also connected to the primary tidal channel 1 and the water body surrounding the shallow wetland 5 through the hydrological connecting ditch 6, thereby ensuring the dynamic exchange and ecological flow of water.

[0095] In the ecological design of the composite habitat enhancement zone and the tidal habitat conservation zone, the water system is cleverly connected to the outside ocean through the first-level tidal channel 1, ensuring that the water in the area can effectively exchange with the outside seawater, maintaining the natural cycle of water quality and ecological balance. Moreover, with the help of the natural dynamics of the tides, the biodiversity in the area is enhanced, greatly improving the vitality and sustainability of the entire ecosystem.

[0096] Through the aforementioned ecological restoration measures, abandoned coastal fishponds were successfully transformed into an ideal wetland ecosystem. This promoted the stable recovery of the high tide salt marsh plant community, dominated by reeds, connected previously isolated water bodies, and achieved comprehensive connectivity of the regional water system, effectively preventing the decline in biodiversity caused by fishpond abandonment. Simultaneously, tidal channels were widened, providing necessary activity space for marine life and ensuring that tidal channels would not disappear due to insufficient hydrodynamics. In the optimization of tidal channels, the role of transverse tidal channels in enhancing carbon sequestration capacity was specifically considered; transverse and tidal channels were strategically placed in key areas to enhance the carbon sequestration function of the salt marsh.

[0097] From the perspective of ecology, wetland ecological restoration is a secondary succession process of natural ecosystem after the disturbance is eliminated. For the coastal salt marsh wetland in the north of Hangzhou Bay, long-term base erosion and exogenous pollution have led to the degradation and disappearance of coastal wetland. In the face of these external disturbances, artificial intervention measures must be taken to ensure the realization of the goal of ecological restoration in a relatively short period of time and to meet the needs of vegetation coverage. On this basis, space should be left for the natural succession process, relying on the self-design and self-organization ability of the ecosystem, and gradually building a coastal abandoned fish pond into a wetland ecosystem with rich biodiversity, perfect structure and function of the ecosystem, efficient energy use, and smooth material circulation. Through comprehensive ecological restoration strategies, not only can the ecological function of the wetland be restored, but also the natural restoration potential of the wetland can be enhanced, thereby providing a solid ecological support for the environmental protection and economic prosperity of the surrounding area.

[0098] The ideal embodiment of the utility model is an inspiration, and through the above description, relevant staff can certainly make various changes and modifications without deviating from the technical idea of the utility model.

[0099] The technical scope of the utility model is not limited to the content of the specification, and must be determined according to the scope of the claims. The technical scope of the utility model is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. An ecological restoration system suitable for use in a coastal abandoned fishpond, characterized in that, It comprises: an ecological barrier buffer zone, which is arranged near the inland side and is used for planting vegetation to shield human activities; a salt marsh habitat zone, which is arranged near the ocean side and comprises a salt marsh beach and a plurality of first-order tidal creeks that penetrate the salt marsh beach and are connected to the ocean; a tidal habitat conservation zone, which is arranged between the ecological barrier buffer zone and the salt marsh habitat zone and is provided with a shallow beach wetland surrounded by water; a compound habitat enhancement zone, which is arranged between the ecological barrier buffer zone and the salt marsh habitat zone and is provided with a salt marsh wetland and a bird habitat island surrounded by water; vegetation for birds to inhabit and forage is planted on the salt marsh, the shallow beach wetland, and the bird habitat island; the water surrounding the shallow beach wetland, the salt marsh, and the bird habitat island is connected to the ocean through the first-order tidal creeks.

2. The ecological restoration system according to claim 1, wherein the compound habitat enhancement zone is further provided with a plurality of transverse tidal creeks and longitudinal tidal creeks, the transverse tidal creeks and the longitudinal tidal creeks separate the salt marsh into a plurality of units, and the transverse tidal creeks and the longitudinal tidal creeks are connected to the water surrounding the salt marsh.

3. The ecological restoration system according to claim 1, wherein in the compound habitat enhancement zone, the water surrounding the salt marsh and the bird habitat island has a water surface elevation greater than or equal to 4.3 m and a bottom elevation greater than or equal to 3.5 m; the salt marsh is at least partially above the water surface, with a height difference greater than or equal to 0.2 m; the bird habitat island is at least partially above the water surface, with a height difference greater than or equal to 1 m.

4. The ecological restoration system according to any one of claims 1-3, wherein the compound habitat enhancement zone is further provided with an ecological beach arranged around the bird habitat island, salt-tolerant plants are planted on at least part of the bird habitat island and the ecological beach.

5. The ecological restoration system according to claim 1, wherein the tidal habitat conservation zone is further provided with a plurality of transverse tidal creeks and longitudinal tidal creeks, the transverse tidal creeks and the longitudinal tidal creeks separate the shallow beach wetland into a plurality of units, and the transverse tidal creeks and the longitudinal tidal creeks are connected to the water.

6. The ecological restoration system according to claim 1 or 5, wherein the tidal habitat conservation zone is further provided with a plurality of water ponds and hydrological connection ditches, the water ponds are connected to the first-order tidal creeks and the water surrounding the shallow beach wetland through the hydrological connection ditches, and adjacent water ponds are connected through the hydrological connection ditches.

7. The ecological restoration system according to claim 1, wherein the salt marsh habitat zone further comprises a plurality of second-order tidal creeks, the second-order tidal creeks separate the salt marsh beach into a plurality of units, and the second-order tidal creeks are connected to the first-order tidal creeks; the width of the second-order tidal creeks is smaller than the width of the first-order tidal creeks.

8. The ecological restoration system according to claim 1 or 7, wherein the salt marsh habitat zone further comprises a plurality of hydrological connection pipes, the hydrological connection pipes are used to connect the first-order tidal creeks and the ocean.

9. The ecological restoration system according to claim 1, wherein the salt marsh habitat zone is further provided with a carbon flux tower for measuring the carbon dioxide exchange amount between the atmosphere and the ecological restoration system.

10. The ecological restoration system according to claim 1, wherein the vegetation is one or more of reed, water candle, sea three prong rush, rush, salsify, sea thrift, rough leaf carex, Chinese lalang, rhinoceros hair, pseudo-woodrush, and sweet clover. and / or, the ecological restoration system further comprises benthic organisms and aquatic organisms disposed in the water body surrounding the shallow marsh, the salt marsh, and the bird habitat island. ​ ​

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