CN111149630A

CN111149630A - Degraded wetland vegetation recovery method

Info

Publication number: CN111149630A
Application number: CN202010061092.XA
Authority: CN
Inventors: 洪剑明; 史国鹏
Original assignee: Capital Normal University
Current assignee: Capital Normal University
Priority date: 2020-01-19
Filing date: 2020-01-19
Publication date: 2020-05-15
Anticipated expiration: 2040-01-19
Also published as: CN111149630B

Abstract

The invention discloses a degraded wetland vegetation recovery method, and belongs to the technical field of environmental protection and ecological engineering. The method comprises the steps of carrying out background condition investigation on a degraded wetland area; selecting a healthy wetland with similar habitat conditions as the degraded wetland as a seed source; and (3) paving soil and replenishing water on the degraded wetland soil paving area by using surface soil containing a soil seed bank in the seed source land so as to recover the degraded wetland vegetation and the like. The method utilizes the soil seed bank of the healthy wetland to carry out ex-situ restoration on the degraded wetland, can obtain remarkable restoration effect within 1-2 years, is easy to operate, has good sustainability, low artificial maintenance and high success rate, and can be used for future ecological construction and wetland restoration engineering.

Description

Degraded wetland vegetation recovery method

Technical Field

The invention belongs to the technical field of environmental protection and ecological engineering, particularly relates to a degraded wetland vegetation recovery method, and particularly relates to a method for rapidly and efficiently recovering degraded wetland vegetation by transplanting a soil seed bank of a healthy wetland to a degraded wetland.

Background

The wetland, the land and the ocean are called three global ecological systems, the ecological service value and the service function of the wetland are the first fingers of the three ecological systems, and the wetland is known as the kidney of the earth. Due to the influence of human over-utilization and climate change, the wetland is in the integral degradation trend in China, the national ecological safety and the sustainable development of the economic society are seriously influenced, and the restoration of the damaged wetland becomes one of the key works of the national ecological construction.

The wetland restoration refers to restoration or reconstruction of a degraded or disappeared wetland through ecological technology or ecological engineering, and the structure and function before interference and related physical, chemical and biological characteristics are reproduced, so that the wetland restoration exerts corresponding ecological functions and provides service values.

At present, the theory for guiding the wetland restoration mainly comprises a secondary succession theory, a self-design theory and an invasion theory. The secondary succession theory considers that as long as the habitat conditions (the most important hydrological conditions for the wetland) of the damaged ecological system are restored to the state before damage, the vegetation (or even the whole biological community) of the system can automatically develop forwards sequentially according to a certain succession track until the habitat conditions are restored to the level before damage. The self-design theory considers that the marsh wetland can be automatically recovered under the micro interference. The invasion theory mainly refers to the influence of foreign species or non-wetland species on wetland vegetation, and the settlement, diffusion and the like of target species, non-target species and foreign species in the damaged wetland can be described by the theory.

One of the technical difficulties of wetland restoration is vegetation restoration, the conditions of lack of a soil seed bank (referring to seeds, fruits, asexual propagules and other reproducible plant structures with reproductive capacity on the soil surface or in a matrix) in an damaged ecological system and the important role of human interference in the whole restoration process are not considered by a secondary succession theory and a self-design theory, and the time for wetland vegetation restoration is usually 15-20 years. At present, the technology mainly used for recovering the vegetation in the wetland is a field planting/regression technology, and a vegetative mass transplanting method, a turf transplanting method and a seed sowing method are mainly adopted to obtain seed plants so as to complete the vegetation recovery. For plants which can be propagated asexually, the nutrient body transplantation is a method with higher success rate, but the method is only suitable for recovering small-area or local vegetation, has poor naturalness, higher maintenance cost, labor and time waste and single landscape; the turf transplanting method has high success rate and good landscape effect, is particularly suitable for the recovery of natural wetlands, but also has the defects of high cost and great damage to the environment; the seed sowing method has low cost and is easy for large-area operation, but the wetland recovery plant species which can be used for the seed sowing method at present are few, and the failure risk is large. The field needs a method for recovering the vegetation of the degraded wetland more quickly and efficiently so as to recover the corresponding ecological functions and ecological values of the degraded wetland.

Disclosure of Invention

Aiming at one or more problems in the prior art, the invention provides a degraded wetland vegetation recovery method, which comprises the following steps:

1) carrying out background condition investigation on the degraded wetland area, wherein the background condition comprises vegetation, a habitat, a soil seed bank and the like;

2) selecting a healthy wetland similar to the habitat conditions of the degraded wetland as a seed source according to the background condition investigation result of the degraded wetland obtained in the step 1); the storage amount of the wetland plant seed bank in the preferable soil of the healthy wetland is not less than 4000 grains/m²The area of the wetland is more than or equal to 2/3 of the total area, the vegetation resource is rich, and no foreign invasive species exists basically; and

3) and (3) paving the soil in the degraded wetland soil paving area by using the surface soil containing the soil seed bank in the seed source land in the step 2) and supplementing water.

The method further comprises a recovery confirmation process, and the current year confirmation measures are as follows: and (3) investigating surface plants (including wetland plants and non-wetland plants) of the degraded wetland in summer and autumn in the year after the degraded wetland is treated in the step 3), and determining that the vegetation recovery of the degraded wetland is successful when the wetland plants in the degraded wetland are of a main plant community type and are compared with the surface plants of the seed source region, and the species number of the wetland plants in the degraded wetland is not less than 1/2 of the species number of the wetland plants of the seed source region.

The method further comprises a recovery confirmation process, and the second-year and third-year confirmation measures are as follows: after determining that the degraded wetland vegetation is successfully recovered in the current year, investigating the soil seed bank of the recovered degraded wetland in spring of the second year and spring of the third year, investigating the vegetation in the region of the recovered degraded wetland in summer of the second year and summer of the third year, and when the number of the wetland plants in the soil seed bank is more than or equal to 1/2 of the number of the wetland plants in the seed bank of the seed source area, and the number of the seeds germinated on the wetland plants is more than or equal to 3500 grains/m²At the same time, the cover of the degraded wetland vegetation is restoredThe degree is obviously greater than 1/2 of the cover degree of the vegetation in the degraded wetland before restoration and the cover degree of the restored vegetation in the degraded wetland is greater than or equal to the cover degree of the vegetation in the seed source, the important value of the wetland plants is obviously greater than 1/2 of the number of the wetland plants in the seed source before restoration, and the success of the vegetation restoration in the degraded wetland area is confirmed.

The investigation of the background condition of the degraded wetland in the step 1) comprises the following steps: vegetation survey, topographic mapping, soil type and physicochemical property determination, hydrological factor determination, climate survey, and soil seed bank survey.

The vegetation survey is carried out by setting survey sampling points, sampling belts and sampling parties, wherein the selection of the sampling points, the sampling belts and the sampling parties is carried out according to a method specified in national wetland resource survey technical regulations; preferably, the content searched for by the plants comprises recording the plant species, the plant number of each plant, the average plant height of each plant, the total coverage and the plant division coverage of each plant in each sample square, wherein the plant division coverage of each plant is the percentage of the vertical projection area of the part of the certain plant on the ground surface in the sample square, and the total coverage is the percentage of the vertical projection area of the part of all the plants on the ground surface in the sample square in the total area of the sample square; and/or

Carrying out on-site survey according to engineering survey standards on the topographic mapping; and/or

The soil type and the physical and chemical properties are measured according to the technical Specification for soil analysis; and/or

The hydrological factor is measured according to national wetland resource survey technical regulation; and/or

The climate survey is to survey the climate condition change conditions of the degraded wetland area through the data of a meteorological station, and comprises average precipitation and annual change thereof, annual average temperature and annual change thereof; and/or

The investigation of the soil seed bank is carried out by adopting a seed germination test, which comprises the steps of collecting plant seeds in the investigated degraded wet area, identifying and statistically analyzing the germinated plants according to the plant species in the soil seed bank, and determining the dominant plant type in the degraded wet soil seed bank.

The specific operation method for determining the dominant plant type in the soil seed bank in the degraded wetland comprises the following steps: counting the types of wetland plants germinated in a soil seed bank of the degraded wetland, classifying the wetland plants according to submerged plants, floating plants, emergent plants and hygrophytes, and determining the type of plants as the dominant plant type when the number of the plants is the most in the four plant types and the number of seeds is also large by combining the corresponding sample prescription of the degraded wetland and the vegetation investigation result in the sample belt; or

Counting the types of wetland plants germinated in the soil seed bank of the degraded wetland, and classifying according to submerged plants, floating-leaf plants, emerging plants and hygrophytes, wherein the number of the germinated seeds in any one of the four plant types is more than 50% of the total number of the germinated wetland plant seeds, and the plant type is determined to be the dominant plant type.

Selecting the seed source area in the step 2) in the peripheral range of the degraded wetland area according to the principle of proximity, wherein the habitat conditions comprise soil types, physicochemical properties, terrain, hydrology and climate factors; preferably, the seed source is selected within 10 kilometers of the degraded wetland square circle;

further preferably, the reserve of the soil seed bank of the wet land plants in the seed source land is not less than 4000 grains/m²The area of the wetland is greater than or equal to 2/3 of the total area, the vegetation resource is rich, no foreign invasive species exists basically, and the dominant plant type in the soil seed bank of the seed source area is similar to the dominant plant type in the soil seed bank of the degraded wetland area.

The specific operation method of the step 3) comprises the following steps:

a. taking soil from a seed source: adopting a stripe method to extract soil before plant germination, wherein the actual soil extraction area is not more than 2% of the suitable soil extraction area;

b. soil paving: the soil paving of the degraded wetland is completed before the rainy season comes, initial water replenishing is carried out after the soil paving is completed, and the initial water replenishing is stopped after the water level reaches a water replenishing contour line; and

c. water supplement control: and (4) performing post-stage water supplement according to the plant types in the soil seed bank of the degraded wetland area and the degraded wetland vegetation type recovery target, and controlling the surface water level and the soil water content of the degraded wetland area.

The step a of taking soil by the strip method is to select strips vertical to the water-land boundary line in a seed source place, take the water-land boundary line to the boundary of the xerophyte community as strip length, take 50 cm-100cm as strip width and take strip spacing distance of 25 m-50 m; preferably, the strip soil-borrowing depth is 15cm, and the vegetation on the earth surface is removed before soil borrowing; and/or

The concrete method for paving the soil in the step b comprises the following steps: removing vegetation residues on the earth surface of the degraded wetland to be paved, taking out surface soil with the depth of 10-20cm from the surface layer, temporarily stacking the surface soil in the open space, and paving seed source surface soil with the depth of 10-20cm on the surface soil to be paved; and/or

The water replenishing contour line in the step b is a corresponding soil paving position extending 5cm in the horizontal direction from the boundary of the soil paving area to the soil paving area; and/or

The water supplementing control method in the step c comprises the following specific steps:

c 1: when submerged plants are taken as dominant plants in a soil seed bank of the degraded wetland area and the submerged plant community is recovered, the water level is controlled to be 30-100 cm deep, the water level at the low-lying position or the middle part of a river channel or a lake reservoir is correspondingly deep, and the edge is 30-35 cm;

c 2: when the soil seed bank of the degraded wetland area contains floating-leaf plants and the goal is to recover floating-leaf and submerged plant communities, the water level is controlled to be 20-80 cm deep, the water level at the low-lying position or the middle part of a river channel or a lake reservoir is correspondingly deep, and the edge is 20-25 cm;

c 3: when emergent aquatic plants are taken as dominant plants in a soil seed bank of the degraded wetland area and the goal is to recover emergent aquatic plant communities, the water level is controlled to be 0-50cm in water depth, the water level at the low position or the middle part of a river channel or a lake reservoir is correspondingly deep, and the edge is 10-15 cm;

c 4: when the soil seed bank in the degraded wetland area takes the hygrophyte as the dominant plant and the aim is to recover the hygrophyte community, the soil moisture content is controlled to be more than or equal to 40 percent.

The main plant community type is determined through the important value in the recovery confirmation process, and the specific method comprises the following steps:

A. according to the survey results (such as data of density, coverage, frequency and the like) of the degraded wetland surface plants in summer and autumn of the year, the important values of the surface plants of each region are obtained,

the importance value is (relative density + relative frequency + relative coverage)/3;

wherein: relative density (density of a certain plant species/total density of all plant species) × 100%;

relative coverage (coverage of a certain plant species/total coverage of all plant species) x 100%;

relative frequency (frequency of a certain plant species/total frequency of all plant species) × 100%;

B. selecting plant species with the importance values which account for the top (for example, the top 10) from large to small according to the numerical values as main plants, respectively adding the acquired importance values of the main plants according to two types of wetland plants and non-wetland plants, and determining the type with the larger numerical value as the type of the main plant community in the restored degraded wetland area.

The vegetation recovery method for the degraded wetland based on the technical scheme can quickly and effectively recover the vegetation of the degraded wetland through a vegetation transplantation ectopic recovery method, and has the following beneficial effects compared with the prior art:

1) the method adopts the surface soil of the seed source healthy wetland similar to the habitat conditions of the degraded wetland to transplant the seed source healthy wetland to the degraded wetland area for ectopic recovery, can obtain obvious vegetation recovery effect within 1-2 years, and has the advantages of easy operation, good sustainability, low manual maintenance and high success rate.

2) The method of the invention is mainly based on natural restoration, and the degraded wetland successfully recovered by the vegetation has various plant species and good landscape naturalness, and is beneficial to expanding the area of the wetland and protecting the biodiversity. The method provided by the invention has wide application prospect in future ecological construction and wetland restoration engineering.

Drawings

Fig. 1 is a schematic diagram showing a structure of a survey sample tape and a sample recipe setting.

Detailed Description

The method is mainly based on a secondary succession theory and a self-design theory, and takes a soil seed bank as an important condition to be considered on the basis of the two theories, so that the method capable of accelerating the recovery process of the degraded wetland vegetation is obtained, and the degraded wetland vegetation can obtain a remarkable recovery effect within 1-2 years by using the method.

The present invention will be described in detail by the following specific embodiments.

The method provided by the invention comprises the steps of comparing the vegetation of the healthy wetland in the area (usually, the area can comprise a degraded wetland area and a healthy wetland area) where the degraded wetland is to be recovered, and transplanting the soil seed bank resources which are still in other healthy wetlands in the area where the degraded wetland is located to recover the vegetation of the degraded wetland, and specifically comprises the following steps:

the method comprises the steps of firstly, carrying out background condition investigation on the degraded wetland area, wherein the background condition investigation comprises vegetation investigation, topographic mapping, measurement of factors such as soil types, physicochemical properties and hydrology, investigation of a soil seed bank, understanding of meteorological conditions (climate investigation) and mastering the background condition of the degraded wetland area. The method comprises the steps of surveying the soil seed bank of the degraded wetland area, uniformly sampling the soil of the degraded wetland area according to a sampling belt method and a sampling method, and determining the reserve capacity condition of the soil seed bank of the degraded wetland area through a seed germination test, plant type identification and quantity statistical analysis, wherein the reserve capacity condition comprises the number of wetland plant seeds germinated in unit area in different subareas, the proportion of the area of each subarea in the total area of the degraded wetland area, the dominant plant type, the types of germinated seeds in the soil seed bank, the number of various types and distribution areas.

1. The specific operation of carrying out background condition investigation on the degraded wetland area comprises the following steps:

1.1, vegetation survey: carrying out vegetation investigation by setting investigation sampling points, sampling belts and sampling parties; if the terrain of the degraded wetland area is complex or greatly changed, the investigation sample points cover different types of areas or changed areas; the sample zone should be selected to better reflect the type of surface vegetation and the basic characteristics of the plant community. The selection of the sample points, the sample belts and the sample parties is carried out by using a conventional method according to national wetland resource survey technical rules (2010 trial edition by the national forestry agency).

In the embodiment of the invention, the sampling points are 5-10 survey points selected along the horizontal line of the bank of a river bank or a lake bank, as shown in fig. 1, the survey sampling points extend from water to the bank along the vertical direction of the bank of the river or the lake bank, three survey sample belts are arranged at equal intervals, the interval d between two adjacent survey sample belts is 50-200 m, and the width of each survey sample belt is 10-30m, preferably 20 m; and (3-5) samples are taken from the onshore part of each investigation sample zone at equal intervals, and 2-3 samples are taken from the water according to the community characteristics.

The size of the selected sample prescription needs to be selected according to different coverage degrees of herbaceous plants and shrubs. When a small amount of shrubs appear in the herbaceous plant community and the coverage degree of the shrubs is less than 25%, selecting according to the herbaceous plant sample prescription; and when the shrub coverage in the vegetation communities on the ground is more than or equal to 25%, selecting according to shrub samples, and simultaneously selecting the communities with the dominant herbaceous plants in shrub areas as herbaceous plant samples. Wherein the coverage refers to the percentage of the partial vertical projection area of the plant on the ground surface to the total area of the sample plot when the plant on the ground surface is investigated.

The following conditions should be satisfied no matter what type of plant (herb and/or shrub) is used as the standard for selecting the formula:

if the herbaceous plants are selected, when the average height of the herbaceous plants is less than 2m, the sampling area of each sample is 1m multiplied by 1 m; when the average height of the herbaceous plant is more than or equal to 2m, taking the area of the sample size to be 2m multiplied by 2 m;

if the shrub is selected according to shrub plants, when the average height of the shrubs is more than or equal to 3m, taking 4m multiplied by 4m as the area of a sample; when the average height of shrubs is 1-3 m, taking the area of a sample of 2m multiplied by 2 m; when the average height of the shrub is less than 1m, the area of the sample is 1m multiplied by 1 m.

Planting the investigated content includes:

A) the plant species, number of plants per species, average plant height per plant, total coverage and individual coverage per plant within each sample are recorded for calculation of significance values. Wherein the ratio of the number of a certain plant in the sample prescription to the area of the sample prescription is used as the density, and the ratio of the sum of the number of all plants in the sample prescription to the area of the sample prescription is used as the total density; the frequency of the appearance of a certain plant in all plant samples is taken as the frequency, namely the number of the appearance of the certain plant samples/the total number of the appearance of the certain plant is multiplied by 100 percent, and the sum of the frequencies of all plants is taken as the total frequency; the percentage of the vertical projection area of the overground part of a certain plant in the area of the sample is taken as the coverage of the plant, and the percentage of the vertical projection area of the parts of all plants on the ground surface in the sample in the total area of the sample is taken as the total coverage; simultaneously recording the dry weight of each plant (including overground and underground parts) which survives in the sample prescription as biomass; the dry weight of all plants living in the same way was taken as the total biomass.

B) And when the plant species which are not recorded in the sample prescription exist around the sample prescription, the plant species are classified into the similar sample prescription to be used as a supplementary record, and the plant species on the earth surface are recorded.

1.2, topographic mapping: the degraded wetland area is surveyed in the field according to engineering survey regulations (GB50026-2007) for topographic mapping, wherein the topographic mapping comprises the shape, the altitude, the slope direction, the gradient, the drawing of regional contour lines and the like of the degraded wetland area.

1.3, investigating soil types and physicochemical properties: the soil type and physicochemical properties of the degraded wetland area are investigated according to the technical Specification for soil analysis, and the main indexes comprise soil water content, salt content, total nitrogen, total phosphorus, organic matters, pH, effective potassium and the like. The heavy metal content of the polluted soil needs to be increased. When the soil moisture content in the sample is measured, relevant instruments, such as a soil moisture meter, can be used for on-site measurement, and the soil sample can be sealed and returned to a laboratory for measurement.

1.4, hydrological investigation: hydrologic monitoring is carried out on the degraded wetland area according to the fifth chapter and the second chapter of the twenty-sixth chapter in the technical rules of national wetland resource survey (the 2010 test edition of the national forestry agency), and the influence of related water sources on the degraded wetland area is known, wherein the main indexes include water level, flood season, ice season, silt quantity, water supply quantity and the like.

1.5, climate survey: and the weather condition change condition of the degraded wetland area is known through weather station data, and the main indexes comprise average precipitation and annual change thereof, annual average temperature and annual change thereof and the like.

1.6, the concrete operation of investigating the soil seed bank in the degraded wetland area is as follows:

1.6.1, seed germination test: taking surface soil in each survey sample in the 1.1, taking 5 times of samples in each survey sample, and sampling by using a soil sampler with the inner diameter of 4cm, wherein the soil sampling depth is 0-6 cm. Taking out 5 plum blossom-shaped soil cores from each sample, filling the soil cores into a sealed bag, and taking the sealed bag back to a laboratory for seed germination test. The method specifically comprises the following steps:

A) uniformly mixing 5 soil cores in the same sample; the uniformly mixed soil sample is firstly screened and washed by a mesh screen with the aperture of 0.2 mm;

B) selecting two germination boxes with the same size, wherein the size of each germination box is 15cm multiplied by 30cm multiplied by 10cm, and paving matrix soil with the thickness of 2-4 cm in each germination box, wherein the matrix soil is marsh soil treated by an oven at 130 ℃ for 3 hours;

C) dividing the soil sample screened in the step A) into 2 parts, wherein 1 part of the soil sample is paved in a germination box, and the soil in the germination box is kept moist; another 1 part of soil sample is flatly paved in another germination box, watered and submerged in the soil sample, and the water depth is 3-5 cm;

D) placing 2 germination boxes in a greenhouse at 20-25 ℃ to receive natural illumination; in the seed germination period (which refers to the whole growing season suitable for germination of different seeds), water is supplemented in time and the requirements of different water levels of soil samples in the germination box are met.

And synchronously performing a seed germination test on each investigation sample according to the method.

1.6.2, plant species identification: based on the seed germination test, the plant species are identified 25 days after the seeds germinate, and the types and the number of the plant germinates in each germination box are counted. And identifying once in 10 days on average, removing the germinated seedlings as soon as possible after identification and counting, and transplanting the seedlings with larger plants but incapable of being identified into an incubator for continuous culture until the seedlings can be identified. Until no seeds germinate, the germination test generally lasts for 4-6 months, after plant species identification and statistical analysis, the reserve capacity conditions of the soil seed banks in each sample party and sample belt are determined, including the number of the wetland plant seeds germinated in unit area in each sample party and sample belt, the species, the number and the distribution area of the wetland plant seeds germinated in the soil seed banks in each sample party and sample belt are determined, and the dominant plant type in the soil seed banks in the degraded wetland area is determined in the following manner.

The dominant plant type was determined by: and counting the types and the number of the wetland plant seeds germinated in the soil seed bank of each sample prescription and sample belt, and classifying according to submerged plants, floating-leaf plants, emergent aquatic plants and hygrophytes. And (3) determining that the type of plant is the dominant plant type when the number of the plant of which type is the most in the 4 plant types and the number of the seeds is large by combining the corresponding sample prescription of the degraded wetland area and the vegetation investigation result in the sample zone, and controlling the water level according to the water level requirement of the type of plant as far as possible during water supplement.

1m was obtained by counting the number of germinated seeds in the germination box by the following formula²The number of wetland plant seeds germinated in the selected wetland is as follows:

y is X X2X 1m²/[π×(0.04m/2)²×5]；

Wherein, the X grains are the total number of the seeds germinated in one box with a larger number of the plants in the germination wetland in the two germination boxes;

π×(0.04m/2)²the area of the sampler with the inner diameter of 4cm is indicated;

5 is the number of the soil sampling cores; 2 is the number of germination boxes;

y is 1m²The number of wetland plant seeds germinated in the selected wetland. Since the germination conditions are divided into two treatments of water logging and wetting, the number of germinated seeds is only counted when the germination number of the wetland plant seeds is the maximum under the two treatments, namely the number of the seeds under the water level condition that one box is most suitable for the germination of the wetland plant seeds under the two treatment conditions is multiplied by 2 to represent the total number of the germinated seeds of the germination plants in the two germination boxes.

According to the formula, the germination quantity of the wetland plant seeds in unit area in each sample can be calculated, and further the germination quantity of the wetland plant seeds at different distances from the water area on a sample belt selected from a certain sample point in a degraded wetland area is determined. According to the area (vertical distance to the water area multiplied by horizontal distance) of the wetland vegetation area planned to be restored and the number of soil seed banks of the samples at different positions on the vertical distance, whether the wetland vegetation needs to be restored by adopting the transplantation method is determined (the number of the seed banks distributed in the samples at the same vertical distance from the normal water waterline is generally similar).

When the number of the germinated wetland plant seeds in the degraded wetland area is 2000 grains/m²When the area of the following subareas exceeds 1/2 of the total area of the degraded wetland area, the degraded wetland area can carry out the transplantation and recovery of the soil seed bank by using the degraded wetland vegetation recovery method provided by the invention, otherwise, the natural recovery is carried out according to the in-situ method (when one wetland seed quantity is more than 2000 grains/m between two continuous sample squares which are vertical to the water level line on the sample belt²And the other is less than 2000 particles/m²In the case of (a), the boundary between the two different recovery methods calculates the area from the middle of the vertical distance between the two squares).

Step two, according to the background (including vegetation, terrain, soil type and physicochemical property as well as hydrology, climate, soil seed bank and other factors) condition of the degraded wetland area obtained in the step one, selecting the area similar to the habitat of the degraded wetland area within the range of 10 kilometers of the degraded wetland area, and the storage capacity of the soil wetland plant seed bank is not less than 4000 grains/m²The area of the wetland is greater than or equal to 2/3 of the total area, the wetland plant resource is rich, and the area basically without external invasive seeds is taken as a seed source area, and the range of the soil taking area is determined in the seed source area. If no suitable seed source is found in the range, the search is continued according to the principle of the search nearby.

The specific operation method comprises the following steps:

selecting conditions similar to the habitat (including soil type, physicochemical properties, terrain, hydrology, climate factors (mainly considering average precipitation and annual change thereof), annual average temperature and annual change thereof) of the degraded wetland area within the range of 10 kilometers of the circumference of the degraded wetland area, and planting the wetland in the soilThe storage capacity of the seed bank is not less than 4000 grains/m²The wetland area of (2) is not less than 2/3 (the investigation method of the soil seed bank of the seed land is described in the same step one), the wetland plant vegetation resource is rich (namely, wetland plants are taken as main plant types (described below) in the healthy wetland of the seed land, and a plurality of (for example, more than 10) wetland plant types exist), the area basically without foreign invasive species is taken as the seed land, and the plant type prevailing in the soil seed bank of the seed land is similar to the plant type prevailing in the soil seed bank of the degraded wetland area. Otherwise, repeating the second step until a proper seed source is found.

The dominant plant type in the soil seed bank of the seed site is determined in the following manner: in the seed bank of the seed source soil, if the number of the germinated seeds of any one of the submerged plant, the floating plant, the emergent aquatic plant or the hygrophyte exceeds more than 50 percent of the total number of the germinated wetland plant seeds, determining that the plant type is the dominant plant type in the seed bank of the seed source soil; if submerged plants, floating plants, emerging plants and hygrophytes grow in a mixed manner, and the number of species of a certain plant type is the largest among 4 types and the number of seeds is also large, the plant type is determined to be the dominant plant type in the soil seed bank of the seed source. Here, a certain type of seed number should be considered first, and then the seed number.

And step three, taking out surface soil containing the soil seed bank from the seed source area, transporting the surface soil to the degraded wetland area, and paving soil at the reserved position of the degraded wetland area. The same management is carried out in the degraded wetland area according to the vegetation management measures of the seed source, and if water needs to be supplemented, the hydrological change is mainly consistent with the hydrological change of the seed source.

The specific operation method comprises the following steps:

1. taking soil from a seed source: the soil borrowing time is determined according to the germination time of local plants on the basis of the principle that the environment of a seed source is not damaged and the diversity of local vegetation is not damaged, the soil borrowing is carried out by adopting a strip method before the plants germinate, and the actual soil borrowing area is not more than 2% of the suitable soil borrowing area.

The strip method soil sampling is to select strips vertical to an amphibious boundary line in a seed source place, take the amphibious boundary line to a xerophyte community boundary as strip length, take 50-100 cm as strip width, take strip spacing distance to be 25-50 m, and dig depth to be 15 cm. Before surface soil excavation, surface vegetation needs to be cut off in an actual soil taking area, manual work and an excavator work in a matching mode, a temporary stacking point guarantees the integrity of the taken surface soil as much as possible, and the surface soil can be covered to prevent rain water and soil loss or be corroded by other things after being aired and smashed. Woven bags or vehicles can be used in the transportation process (if the woven bags or the vehicles are laid at that time, the woven bags or the vehicles can be directly transported to a laying place, and the woven bags or the vehicles are fully mixed for laying).

2. Soil paving: the reserved position of the degraded wetland area is used as a soil paving area, namely an area needing replacing the soil seed bank, and the reserve volume of wetland plant seeds in the soil seed bank is determined by investigation of the soil seed bank and is less than or equal to 2000 grains/m²The area of (2) is used as a soil paving area. Before the soil is paved, the soil paving area needs to be pretreated, namely, an excavator is used for digging soil with the surface layer of about 20cm, the dug soil is properly stacked for later land filling or paving the soil back to a seed source soil fetching position or near processing, and transportation funds are saved. And for the conditions that the soil is polluted, the gravel content in the soil is too much and the like, digging is needed according to actual conditions, the depth is not more than 50cm, treating the polluted soil by burning, landfill, solidification, biochemistry and the like, and transplanting a seed bank of the soil of the seed source area after the polluted soil and the gravel are partially dug out. For the situation that the terrain needs to be rectified and reformed, the terrains with different elevations can be reformed and formed according to the prior planning, such as bird habitat design, vegetation landscaping and other effects, so as to form corresponding different habitat types of shallow water areas, deep water areas and the like.

The soil paving work of the degraded wetland area needs to be finished before the rainy season comes, and when the soil is paved, the soil is paved in the area where the surface soil is taken away. After the soil is paved, the management measures of the degraded wetland area are kept to be the same as those of the seed source area, and if the interference of grazing, mowing, farming and the like exists, the management measures are needed to be performed again within 6 months to 1 year after the soil is paved. The method comprises the steps of paving soil in a degraded wetland area, then replenishing water to a soil paving area, and stopping replenishing water after the water level reaches a water replenishing contour line of the soil paving area, wherein for the soil paving areas with different water level requirements, soil at different water levels of a seed land is correspondingly selected to be paved, and the water replenishing contour line is arranged at a corresponding soil paving position extending 5cm from the boundary of the soil paving area after soil paving to the soil paving area in the horizontal direction (for example, when a lake basin is used as the soil paving area to pave soil, the lake basin gradually descends slowly from the lake edge to the lake, and the lake edge is mostly wet and emergent aquatic plants, so that water at the corresponding soil paving position extending 5cm from the surface boundary of the soil paving area to the lake in the horizontal direction can horizontally move towards the boundary of the soil paving area, the soil water content at the time can meet the growth of the wet and emergent plants, and a certain amount of water can be saved, because if the slope of the lake basin is larger, the height in the vertical direction corresponding to 5cm in the horizontal direction can be 3cm, requiring a greater amount of water for replenishing). The water level is quickly reduced in the initial stage of water supplement, so that the early stage water supplement period is short, and the water quantity is large, so that sufficient water quantity supply is ensured. And determining the optimum water replenishing level by combining the infiltration coefficient of the soil, the evaporation rate of the water, the growth condition of the vegetation and the vegetation recovery target under the conditions that the water content of the soil is basically saturated and the water level is reduced and slowed down in the later period.

3. Water supplement control: the plant types in the soil seed bank include submerged plants, floating plants, emerging plants and hygrophytes; according to the relation between the natural distribution of wetland plants and the water level gradient in a seed source area and a degraded wetland area, the method is suitable for growing submerged plants in an area with water depth of about 100cm and good transparency; in the area with the water depth of 30cm-100cm, floating leaves and submerged plants are suitable to grow; emergent aquatic plants are suitable to grow within the water depth of 50 cm; the moisture content of the soil is about 40%, and the soil is suitable for growing the hygrophytes. According to the actual situation, the control of the surface water level and the soil water content of the degraded wetland area is generally carried out according to the following indexes:

1) when the soil seed bank of the degraded wetland area takes the submerged plants as the dominant plants and the goal is to recover the submerged plant community, the water level is controlled to be 30-100 cm deep, the water level at the low-lying position or the middle part of the river channel or the lake reservoir is correspondingly deep, and the edge is

2) When the soil seed bank of the degraded wetland area contains floating-leaf plants and the target is to recover floating-leaf and submerged plant communities, the distance between the floating-leaf and submerged plant communities can be about 30-35 cm; the water level is controlled to be 20cm to 80cm in depth, the water level at the low-lying position or the middle part of a river channel or a lake reservoir is correspondingly deeper, and the edge can be about 20cm to 25 cm;

3) when emergent aquatic plants are taken as dominant plants in a soil seed bank of the degraded wetland area and the emergent aquatic plant community is recovered, the water level is controlled to be 0-50cm in water depth, the water level at the low-lying part or the middle part of a river channel or a lake reservoir is correspondingly deep, and the edge can be about 10-15 cm;

4) when the plants dominated by the hygrophytes are in the soil seed bank of the degraded wetland area and the goal is to restore the hygrophyte community, the soil moisture content is controlled to be around 40% or higher.

The water source for recovering and replenishing the degraded wetland vegetation is mainly surface water or reclaimed water which is treated and discharged after reaching standards. Wherein, surface water is preferably led from rivers, lakes and reservoirs, and reclaimed water is preferably discharged to reach the discharge standard (meeting the national standard of more than A level). At the initial stage of recovery, the water depth can be halved according to the water level standard, and the water level of the corresponding degraded wetland area can be gradually increased to reach the standard along with the germination of seeds and the growth of plants in the degraded wetland area. And the underground water is considered to be pumped for emergency water supplement only under special conditions.

Because the wetland is degraded due to drought or water shortage and other uses after water drainage, before water is supplemented in a degraded wetland area caused by water shortage and drought, the water level elevations of different subareas after water supplementation are determined, and whether micro-terrain reconstruction is needed or whether auxiliary facilities such as a culvert gate for controlling the water level are needed to be arranged at a proper position of the degraded wetland area to control the water level and the soil water content is determined according to the current situation of the water level elevations.

And (4) surveying the vegetation of the degraded wetland area every year after the third step is finished, and continuously surveying for three years to confirm whether the vegetation recovery of the degraded wetland is successful. The confirmation measures include:

firstly), investigating the land plants in the degraded wetland area in summer and autumn in the current year, acquiring important values of the land plants (the calculation method of the important values is described in detail below), and comparing the important values with the number of species in the seed source area; and (4) determining whether the wetland plants in the degraded wet area are dominant plant communities (detailed below) according to the important values, wherein the species number of the wetland plants is not less than 1/2 of the species source wetland plant species number, the degraded wetland plants are successfully recovered, and otherwise, returning to the step two.

Referring to the description in the step one, the method for surveying the vegetation in the restored degraded wetland area firstly records the density, coverage degree, frequency and the like of the vegetation on the ground surface of the restored degraded wetland area in a sample belt and sample square mode, and calculates the important values of different plants. Important values (i.v.) are proposed by american j.t.curtis and r.p.mcintosh (1951), meaning a comprehensive quantitative indicator of the status and role of a certain species of plants in a plant community; the calculation formula is as follows:

the density is the plant number per unit area, and d is expressed as N/S by a formula;

wherein: n is the number of individuals of a certain plant in the selected square, and S is the area of the selected square.

Then, plant species with the top importance value (for example, the top 10) are selected from the top according to the numerical values, the importance values of the obtained main plants are added according to the types of the main plant communities (wetland plants and non-wetland plants), the plant community type with the larger numerical value is determined as the main plant community type of the restored degraded wetland area, when the wetland plants in the restored degraded wetland area are of the main plant community type and the number of the species of the wetland plants is more than or equal to 1/2 of the number of the species of the wetland plants in the seed area compared with the number of the species of the wetland plants in the seed area, the success of vegetation restoration is confirmed. The specific operation is as follows:

A) respectively counting the types of submerged plants, floating plants, emergent plants, hygrophytes and mesoplants in different sections according to the water level change gradient, positioning the plants to corresponding sections, and counting the soil water content of the corresponding sections so as to provide reference basis for subsequent wetland management and wetland water supplement;

B) calculating the important values of all plants in the degraded wetland area and the seed source area, and selecting the plants with the important values in front as main plants according to the numerical values of the important values from large to small; calculating the soil water content of the main plant colony area to master the rule of different wetland plant types for the requirement of the soil water, and providing a reference basis for the regulation and control of the soil water content of different wetland plant communities in the subsequent wetland management; only the number of species and the coverage of different kinds of plants are recorded for submerged plants and floating-leaf plants in water;

C) determining whether the main plants are wetland plants or not by contrasting the local wetland plant directory or the Chinese wetland plant directory; summing the important values of all wetland plants, summing the important values of all non-wetland plants, and determining the dominant community types of the main plants which have higher important values after the summation and are used as the degraded wetland area and the seed source;

D) and when the wetland plants in the degraded wetland area are in the main plant community type and the number of the wetland plants is not less than 1/2 of the number of the wetland plants in the seed source area, indicating that the degraded wetland vegetation is successfully recovered.

Secondly) after the degraded wetland vegetation is successfully recovered through the first measure), in the spring of the second year and the spring of the third year, investigating a soil seed bank of the recovered degraded wetland area, wherein the number of wetland plants in the soil seed bank is not less than 1/2 of the number of wetland plants in a seed source area, and the number of the germinated seeds of the wetland plants is not less than 3500 grains/m². In summer of the second year and summer of the third year, the vegetation in the restored degraded wetland area is investigated, and the coverage of the restored degraded wetland vegetation is obviously greater than that before restoration and is not less than 1/2 of the coverage of the vegetation in the seed source area; the important value of wetland plants of the restored degraded wetland is obviously greater than that before restoration, and the number of wetland plants is not less than 1/2 of the number of plants of the seed source wetland, so that the success of vegetation restoration of the degraded wetland area is confirmed.

Wherein, the number of the germinated plant seeds of the wetland plants is counted by adopting the following formula:

x2 × 1/[ pi × (0.0)4m/2)²×5]；

Wherein, the X grains are the total number of the seeds germinated in one box with a large number of the plants in the germination wetland in the two germination boxes;

y is 1m²The number of wetland plant seeds germinated in the selected wetland.

The method for investigating the soil seed bank of the restored degraded wetland and the method for investigating the planting are described in the step one.

Example 1:

aiming at a certain degraded wetland for many years, the degraded wetland vegetation recovery method is adopted, and the land vegetation transplantation is carried out on the degraded wetland by utilizing the seed bank resources of the healthy wetland soil of the seed source area (the concrete process refers to the steps I to III), wherein the important values are calculated as follows:

(1) sampling the selected seed source healthy wetland, performing seed germination tests, identifying plant species and counting the number (the specific method is as described in the step one), so as to obtain 47 species (including 35 species of wetland plants and 12 species of non-wetland plants) of the seed source healthy wetland,

taking wetland plant bidens trifoliata as an example to calculate the important value:

importance value ═ relative density + relative frequency + relative coverage)/3

Wherein the relative density is: 407/2122 x 100% ═ 26.30%

The relative frequency is: 0.5/8.5 × 100% ═ 5.88%

The relative coverage is: 164/615 x 100% ═ 26.67%

The important value of the trilobed bidens is 19.62 percent

Calculating the important values of 35 wetland plants and 12 non-wetland plants one by one according to the calculating method of the important values, and selecting plant species with the important values accounting for the first 10 as main plants:

wherein the wetland plants are 6; bidens pilosa, 19.62%; 16.54 percent of scirpus planiculmis; 5.31 percent of cyperus rotundus; 2.01 percent of Chinese iris; 0.97 percent of wild rice stem; inula flower, 0.88%; 4 non-wetland plants, 10.36% of fimbristylis dichotoma; 8.57% of Toxicodendron chinense; bermudagrass, 2.51%; 1.16 percent of mugwort; adding the important values of the 6 wetland plants to obtain the important value of the wetland plants of the source healthy wetland, wherein the important value of the wetland plants is 45.33%; the important values of the 4 kinds of non-wetland plants are added to obtain that the important value of the non-wetland plants of the source healthy wetland is 22.60%, and the important value of the wetland plants is far greater than that of the non-wetland plants, so that the main plant type of the source healthy wetland can be determined to be wetland plants.

(2) And (3) sampling degraded wetland which is successfully recovered by a soil seed bank of the transplanted seed source healthy wetland, performing seed germination tests, plant species identification and quantity statistics (the specific method is as described in the step one), and obtaining the total number of the species of the wetland plants and the non-wetland plants (including 25 wetland plants and 13 non-wetland plants) of the recovered degraded wetland.

Taking a cattail which is a recycled degraded wetland reclaimed water plant as an example, calculating an important value:

the importance value of Typha angustifolia is (relative density + relative frequency + relative coverage)/3

Wherein the relative density is: 246/1734 x 100% ═ 14.19%

The relative frequency is: 0.5/7.2 × 100% ═ 6.90%

The relative coverage is: 180/486X 100% ═ 37.04%

The important value of the cattail is 19.36 percent

Calculating the importance values of the 25 wetland plants and the 13 non-wetland plants according to the calculation method of the importance values, and selecting plant species with the importance values accounting for the top 10 as main plants:

wherein the wetland plants are 6; typha, 19.36%; 12.34 percent of inula flower; 8.06 percent of cress; 4.83 percent of reed; 2.89% of polygonum hydropiper; 1.19 percent of scirpus planiculmis; 4 kinds of non-wetland plants, namely, elymus dahuricus, 15.33 percent; mugwort, 3.31%; 0.98 percent of sow thistle; 0.76 percent of artemisia capillaris; adding the important values of the 6 wetland plants to obtain the important value of the wetland plants with the recovered degraded wetland, wherein the important value of the wetland plants is 48.67 percent; the important values of the 4 kinds of non-wetland plants are added to obtain the important value of the non-wetland plants of the restored degraded wetland, which is 20.38%, and the important value of the wetland plants is larger than that of the non-wetland plants, so that the main plant type in the restored wetland can be determined to be the wetland plants.

From the above data acquisition and comparison of important values, it can be confirmed that the main plant type in the restored degraded wetland is wetland plants, and the species number of the wetland plants is 25, which is higher than 1/2, i.e. 18, of the species number of the wetland plants in the seed-source healthy wetland; the soil seed bank of the degraded wetland transplanting seed source land successfully recovers the vegetation on the earth surface.

(3) In the spring of the second year and the spring of the third year after the degraded wetland vegetation is successfully recovered, the soil seed bank of the recovered degraded wetland is investigated, in the summer of the second year and the summer of the third year, the vegetation in the region of the recovered degraded wetland is investigated, the number of the wetland plants in the soil seed bank is not less than 1/2 of the number of the wetland plants in the seed bank of the seed source, and the number of the seeds of the plant of the recovered degraded wetland which have germinated is not less than 3500 seeds/m²The vegetation coverage of the restored degraded wetland is obviously greater than that of the vegetation coverage of the seed source land which is not less than 1/2 before restoration; the important value of wetland plants of the restored degraded wetland is obviously greater than that before restoration, and the number of wetland plants is not less than 1/2 of the number of plants of the seed source wetland, so that the success of vegetation restoration of the degraded wetland area is confirmed.

Carrying out vegetation investigation and soil seed bank investigation on the seed source healthy wetland and the restored degraded wetland:

(1) through sampling the seed source healthy wetland, performing a seed germination test, identifying the plant species and counting the number (the specific method is described in the step one), the total plant number of the seed source healthy wetland is 45, wherein 34 wetland plants are obtained; the total seed quantity in the germination box is X and the wetland plant seed quantity is X wet.

The total plant seed number in the healthy wetland of the seed source is as follows: y X × 2 × 1m²/[π×(0.04m/2)²×5]

Y148/0.02512 5879 grains/m²

Number of wetland plant seeds in the healthy wetland of the seed source: wet Y ═ wet X2X 1m²/[π×(0.04m/2)²×5]

Y wet 113/0.02512 4498 grains/m²

(2) The total plant number of the restored degraded wetland is 36, wherein 24 plants are obtained by sampling, seed germination tests, plant species identification and quantity statistics (the specific method is described in the step one); the total seed number X 'in the germination box and the wetland plant seed number X' are wet.

The total plant seed number in the recovered degraded wetland is as follows: y '═ X' × 2 × 1m²/[π×(0.04m/2)²×5]

Y172/0.02512 6821 grains/m²

The number of wetland plant seeds in the recovered degraded wetland is as follows: y' wet X2X 1m²/[π×(0.04m/2)²×5]

Y' wet 102/0.02512 4060 grains/m²

Wet Y': y wet 4060/4498X 100% > (90.26% > 1/2)

By the above plant species comparison and seed number comparison: the number of the wetland plants in the soil seed bank of the recovered degraded wetland is greater than 1/2 of the number of the wetland plants in the healthy wetland of the seed source, and the number of the seeds of the recovered wetland plants is greater than or equal to 3500 m²And the species number of the wetland plants in the degraded wetland is restored to be 24 and is greater than 1/2 (namely 17) of the species number of the wetland plants in the seed source region, and the success of vegetation restoration of the degraded wetland area is confirmed.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The method for recovering the vegetation in the degraded wetland is characterized by comprising the following steps:

2. The method of claim 1, further comprising a recovery validation process, wherein the current year validation measures are: and (3) investigating surface plants (including wetland plants and non-wetland plants) of the degraded wetland in summer and autumn in the year after the degraded wetland is treated in the step 3), and determining that the vegetation recovery of the degraded wetland is successful when the wetland plants in the degraded wetland are of a main plant community type and are compared with the surface plants of the seed source region, and the species number of the wetland plants in the degraded wetland is not less than 1/2 of the species number of the wetland plants of the seed source region.

3. The method of claim 2, further comprising a recovery validation process, wherein the second year and third year validation measures are: after determining that the degraded wetland vegetation is successfully recovered in the current year, investigating the soil seed bank of the recovered degraded wetland in spring of the second year and spring of the third year, investigating the vegetation in the region of the recovered degraded wetland in summer of the second year and summer of the third year, and when the number of the wetland plants in the soil seed bank is more than or equal to 1/2 of the number of the wetland plants in the seed bank of the seed source area, and the number of the seeds germinated on the wetland plants is more than or equal to 3500 grains/m²Meanwhile, the coverage of the recovered degraded wetland vegetation is obviously greater than that of the original wetland vegetation before recovery and is not less than 1/2 of the coverage of the seed source wetland vegetation, the important value of wetland plants is obviously greater than that before recovery, the number of wetland plants is not less than 1/2 of the number of the seed source wetland plants, and the success of the vegetation recovery of the degraded wetland area is confirmed.

4. The method according to any one of claims 1 to 3, wherein the background condition investigation of the degraded wetland in the step 1) comprises: vegetation survey, topographic mapping, soil type and physicochemical property determination, hydrological factor determination, climate survey, and soil seed bank survey.

5. The method of claim 4, wherein the vegetation survey is conducted by setting survey spots, zones and squares, wherein the spots, zones and squares are selected according to the method specified in national wetland resource survey technical code; preferably, the content searched for by the plants comprises recording the plant species, the plant number of each plant, the average plant height of each plant, the total coverage and the plant division coverage of each plant in each sample square, wherein the plant division coverage of each plant is the percentage of the vertical projection area of the part of the certain plant on the ground surface in the sample square, and the total coverage is the percentage of the vertical projection area of the part of all the plants on the ground surface in the sample square in the total area of the sample square; and/or

6. The method of claim 5, wherein the specific operation of determining the dominant plant type in the soil seed bank in degraded wetland is: counting the types of wetland plants germinated in a soil seed bank of the degraded wetland, classifying the wetland plants according to submerged plants, floating plants, emergent plants and hygrophytes, and determining the type of plants as the dominant plant type when the number of the plants is the most in the four plant types and the number of seeds is also large by combining the corresponding sample prescription of the degraded wetland and the vegetation investigation result in the sample belt; or

7. The method according to any one of claims 1 to 6, wherein the seed source is selected in step 2) within the peripheral range of the degraded wetland area on a near basis, and the habitat conditions comprise soil type and physicochemical properties, terrain, hydrology and climate factors; preferably, the seed source is selected within 10 kilometers of the degraded wetland square circle;

8. The method according to any one of claims 1 to 7, wherein the specific operation method in step 3) is as follows:

9. The method according to claim 8, wherein the banding borrowing in the step a is that the banding perpendicular to the land-water boundary line is selected at the seed site, the land-water boundary line to the boundary of the xerophyte community is taken as the banding length, the 50 cm-100cm is taken as the banding width, and the banding interval is 25 m-50 m; preferably, the strip soil-borrowing depth is 15cm, and the vegetation on the earth surface is removed before soil borrowing; and/or

10. The method according to any one of claims 2 to 9, wherein the primary plant community type is determined by importance during restoration confirmation by: