A method for transforming a community of an alien mangrove plant, bruguiera gymnohizia, in a difficult site

Abstract

The application discloses a kind of difficult stand beach intertidal alien mangrove plant Laganum community transformation method, belong to mangrove planting technical field;Steps include: S1, mangrove present situation investigation;S2, beach protection repair measure;S3, Laganum pruning or felling;S4, plant mangrove forest;S5, management and protection;S6, effect evaluation;The method can be grown to Laganum community renewal reconstruction in seawater scouring area, avoid reconstruction failure risk, compared with other conventional methods reconstruction repair early canopy forestation;After taking beach protection measure, the beach of repair area is stable, avoid being lost by tidal scouring and leading to sediment;Use old fishing net to protect, avoid that marine litter enters repair area;Use small block to level, keep original Laganum root system, there are few biologicals in woodland in early reconstruction period, such as crab, reduce the interference and damage to new planting seedling, guarantee mangrove seedling survival rate;Using seedling planting that is cultivated under the condition of high salinity environment, seedling resistance is strong, recovery growth speed is fast, survival rate is high.

Description

Technical Field

[0001] This invention relates to the field of mangrove plant Lagannia fraseri cultivation technology, and in particular to a method for transforming Lagannia fraseri communities in difficult-to-establish mangrove tidal flats. Background Technology

[0002] Mangroves grow in the intertidal zone of tropical and subtropical coasts, playing a vital role in wind and wave protection, shoreline conservation, and siltation, serving as an important barrier for maintaining coastal ecological security. *Lagerstroemia indica*, a mangrove species native to Mexico, was introduced to my country in 1999. Due to its strong salt tolerance, it has been widely planted in southeastern coastal areas of my country. However, because of its tall stature, rapid growth, high seed yield, high seed germination rate, and rapid spread, it has significantly impacted native mangrove species native to southeastern coastal my country, showing a clear invasive trend. A joint document on mangrove protection and restoration issued in 2020 explicitly states that artificial pure stands and mangroves invasive by pests should be restored through methods such as modification and removal. Many provinces have explicitly banned the planting of *Lagerstroemia indica* and other exotic mangrove species. The *Hainan Province Mangrove Protection Regulations* explicitly state the need to gradually clear and modify the exotic mangrove species *Lagerstroemia indica* using native tree species to restore native mangrove communities.

[0003] In coastal intertidal mangrove distribution areas, seawater erosion is significant. Directly felling pure stands of *Rhizophora stylosa* and then planting native mangrove plants inevitably leads to the erosion and loss of tidal flat sediments, loss of suitable afforestation land, and inability of mangrove plants to grow normally, resulting in restoration failure. Therefore, it is necessary to mitigate seawater erosion of suitable afforestation land by constructing protective measures; at the same time, appropriately increasing the size of seedlings planted in thinning areas will allow the planting area to achieve canopy closure as soon as possible. Selecting native tree species with prop roots, such as *Rhizophora stylosa* and *Rhizophora mangrovea*, for planting will weaken seawater erosion of the shoreline through the high-density prop root action, providing favorable conditions for the planting of other native mangrove plants and natural regeneration. Summary of the Invention

[0004] The present invention aims to provide a method for transforming the alien mangrove plant Lagannia latitudinata community in difficult-to-establish mudflats, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for transforming a difficult-to-establish mangrove community in tidal flats, comprising the following steps:

[0007] S1. Current status survey of mangrove plants: Use drones to survey the appearance, distribution and area of ​​the Laguanmu community; use artificial ground surveys to investigate the spacing between rows and plants and the size of plants in the Laguanmu community; and formulate measures for the renewal and transformation of the Laguanmu community based on the survey indicators.

[0008] S2. Beach protection and restoration measures: Construct a beach protection dike 1m away from the edge of the Laguanmu forest.

[0009] S3. Pruning or felling of trees.

[0010] S31. The work area is divided into two work areas. A 5-meter-wide forest belt is designated as a thinning area in the forest edge area where sediment is easily lost. Other work areas are designated as direct clear-cutting areas.

[0011] S32. Pruning: Prune the thinning area of ​​the mangroves in alternating rows, remove all lateral branches, increase light in the forest, and provide conditions for the growth of other mangrove plants in the forest. The number of plants pruned is 50% of the mangroves in the thinning area.

[0012] S33, felling

[0013] S331. All the clear-cutting trees in the clear-cutting area shall be cut down. The height of the cut tree stumps shall be less than 10cm. The stumps shall be wrapped tightly with opaque black plastic film to prevent new shoots from sprouting from the stumps.

[0014] S332. Remove the unpruned lateral branches of the pruning trees in the thinning area in alternating rows, with the number of trees removed being 50% of the pruning area's pruning trees; the height of the removed pruning tree stumps should be less than 10cm, and after removal, the stumps should be tightly wrapped with opaque black plastic film to prevent the stumps from sprouting new branches.

[0015] S333. One year later, all the remaining pruning trees in the thinning area were felled, and the felled tree stumps were wrapped tightly with opaque black plastic film to prevent the stumps from sprouting new branches.

[0016] S4. Planting mangroves

[0017] S41. In the Laguan clear-cutting area, based on the tidal flat elevation, select one-year-old native mangrove seedlings and plant them at a size of 1m×1m.

[0018] S42. In the thinning area of ​​the Laguan tree, select 2-3 year old red sea olive or red mangrove seedlings and plant them at a size of 0.5m×0.5m.

[0019] S5. Management and maintenance: After the mangrove seedlings are planted, use 10cm×10cm mesh nets to enclose the mangrove seedlings along the revetment in the restoration area to reduce marine debris from being carried into the forest and damaging the mangrove seedlings. The nets will be removed after one year.

[0020] S6. Effect evaluation, mainly based on the shoreline preservation rate, the sprouting rate of *Lysimachia clethroides*, and the growth of planted seedlings;

[0021] The main investigation and assessment of the shoreline preservation rate is whether the sediment in the tidal flats of the restoration area has been eroded, resulting in a decrease in the elevation of the tidal flats and degradation of suitable afforestation land.

[0022] The main investigation into the suckering rate of the stumps is whether new suckers have sprouted. Suckers from the stumps affect the transformation effect, and a large number of suckers will lead to transformation failure.

[0023] The survey and evaluation of the growth of planted seedlings mainly includes the survival rate of seedlings and the natural regeneration situation. A survival rate of over 90% for seedlings in thinning areas and over 70% for seedlings in clear-cutting areas can ensure the effectiveness of the transformation.

[0024] Preferably, the method for constructing the revetment in step S2 includes:

[0025] Use old fishing nets to pack discarded oyster shells, each weighing 15-20 kg, and transport them to the Laguanmu Renovation Area. Stack them in a trapezoidal shape in the direction of tides to form a wave-dissipating and beach protection dike. The dike is 100 cm wide at the bottom, 40 cm wide at the top, and 30 cm high.

[0026] Preferably, in step S41, the seedlings selected must be cultivated in an environment with a water salinity > 20‰, the soil ball diameter of the seedlings must be 10-12cm, and the seedling height must be 50-60cm.

[0027] Preferably, in step S42, the seedlings selected should be cultivated in an environment with a water salinity > 20‰, with a soil ball diameter of 20-25cm, a seedling height > 80cm, and 3-5 prop roots on the main stem.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. After the application of the embankment protection, the restored tidal flats are stable and will not be eroded by tides, resulting in the loss of sediment (soil).

[0030] Second, using old fishing nets for enclosure can prevent or minimize marine debris from entering the restoration area, thus reducing damage and loss to seedlings caused by marine debris.

[0031] 3. Use small blocks of 0.3m×0.3m×0.3m for land preparation. The original root system of the mangroves is preserved in the mudflats where pits are not dug. There are few marine animals such as crabs in the forest land in the early stage of the transformation, thereby reducing the disturbance and damage to the newly planted seedlings and resulting in a high survival rate of the newly planted mangrove seedlings.

[0032] Fourth, use seedlings cultivated under conditions of high salinity (salinity > 20‰) for planting. These seedlings have strong resistance, fast recovery and growth, and high survival rate.

[0033] In summary, this invention can effectively regenerate and transform *Lagerstroemia indica* communities growing in seawater erosion areas, avoiding the risk of transformation failure and achieving canopy closure and forest formation 1-2 years earlier than other conventional methods. Three years after transformation, the number of marine benthic animal species in the forest is more than three times that of the original *Lagerstroemia indica*. Attached Figure Description

[0034] Figure 1 A flowchart illustrating a method for transforming a difficult-to-establish alien mangrove community in tidal flats;

[0035] Figure 2 This is a cross-sectional view of the embankment.

[0036] Figure 3 This is a schematic diagram of the layout of the restoration area;

[0037] Figure 4 Schematic diagram of the implementation of the protective dike between Wild Pineapple Island and Xinghui Village;

[0038] Figure 5 A schematic diagram of land preparation on Wild Pineapple Island;

[0039] Figure 6 This is a schematic diagram of the land preparation in Xinghui Village. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments:

[0041] like Figure 1 As shown, the specific steps of a method for transforming an introduced mangrove community in a difficult-to-establish mudflat include:

[0042] 1. The current status survey of mangrove plants includes: using drones to survey the appearance, distribution and area of ​​the Laguan tree community; using artificial ground surveys to investigate the spacing between rows and plants and the size of plants in the Laguan tree community; and formulating measures for the renewal and transformation of the Laguan tree community based on the survey indicators.

[0043] 2. Beach protection and restoration measures

[0044] like Figure 2 As shown, repair the beach dike 1m away from the edge of the Laguanmu forest. The method for constructing the beach dike is as follows: use old fishing nets to pack discarded oyster shells, each bag weighing 15-20kg, and transport them to the Laguanmu renovation area. Stack them in a trapezoidal shape in the direction of tide ebb and flow to form a wave-dissipating beach dike. The bottom of the beach dike is 100cm wide, the top is 20cm wide, and the height is 30cm.

[0045] 3. Prune and remove branches from trees, such as... Figure 3 As shown

[0046] 3.1 Thinning operations

[0047] The 5-meter-wide forest belt at the edge of the Laguanmu restoration area is designated as a thinning area.

[0048] 3.1.1 Pruning

[0049] Prune the thinning area of ​​the *Pterocarya stenoptera* in alternating rows, removing all lateral branches to increase light penetration in the forest. The number of trees with pruned lateral branches should be 50% of the total number of *Pterocarya stenoptera* trees in the thinning area.

[0050] 3.1.2 Remove the unpruned lateral branches of the thinning area, and remove 50% of the thinning area's total number of trees. The height of the removed tree stumps (stubble) should be less than 10cm. After removal, wrap the stumps tightly with opaque black plastic film to prevent new shoots from sprouting from the stumps.

[0051] 3.1.2 One year later, all remaining pruning trees in the thinning area should be felled, and the felled tree stumps should be tightly wrapped with opaque black plastic film to prevent new shoots from sprouting from the stumps.

[0052] 3.2 Clearcutting Operation

[0053] 3.2.1 Except for the thinning area, all areas where saplings grow in the restoration area are clear-cutting operation areas.

[0054] All the clear-cutting trees in the clear-cutting area were felled. The stumps of the felled trees were less than 10cm high. The stumps were wrapped tightly with opaque black plastic film to prevent new shoots from sprouting from the stumps.

[0055] 4. Plant mangroves

[0056] 4.1 Dig a pit near the location of the logging stake, with the pit dimensions being 0.3m × 0.3m × 0.3m. Remove the sediment and tree roots from the pit and break them up at the edge of the pit for later use.

[0057] 4.2 In the clear-cutting area, based on the tidal flat elevation, select one-year-old native mangrove seedlings and plant them at a size of 1m × 1m. The required seedlings need to be cultivated in an environment with a water salinity > 20‰, with a root ball diameter of 10-12cm and a seedling height of 50-60cm.

[0058] 4.2 In the thinning area, select 2-year-old red olive or true red olive seedlings and plant them at a size of 0.5m × 0.5m. The required seedlings need to be cultivated in an environment with a water salinity > 20‰, with a root ball diameter of 20-25cm, a seedling height > 80cm, and 3-5 prop roots on the main stem.

[0059] 5. Maintenance

[0060] After the mangrove seedlings are planted, they are enclosed in the restoration area along the revetment with nets with a mesh size of 10cm×10cm to reduce marine debris from drifting into the forest and damaging the mangrove seedlings. The nets are removed after one year.

[0061] 6. Effectiveness Evaluation

[0062] The effectiveness assessment mainly focuses on the shoreline preservation rate, *Rhizophora stylosa* sprouting rate, and the growth of planted seedlings. The shoreline preservation rate primarily investigates whether erosion of the tidal flat sediments in the restoration area has led to a decrease in tidal flat elevation and degradation of suitable afforestation land. *Rhizophora stylosa* sprouting rate primarily investigates whether stumps have sprouted new shoots; sprouting shoots from stumps can affect the restoration effect, and excessive sprouting can lead to restoration failure. The assessment of planted seedling growth mainly includes seedling survival rate and natural regeneration. The survival rate of *Rhizophora stylosa* seedlings in the thinned area is over 90%, and the survival rate in the clear-cut area is over 70%, with propagules of other native tree species regenerating and growing on the forest land.

[0063] The specific implementation process is as follows:

[0064] This paper takes the Wild Pineapple Island in Dongzhai Port Nature Reserve, Hainan Province, and the Laguanmu Renewal and Transformation Site in Xinghui Village as examples to introduce specific case studies of the Laguanmu Renewal and Transformation Project.

[0065] 1. Use drones to investigate the appearance and distribution of the *Lagerstroemia indica* community, and combine this with computer calculations to determine the area of ​​the *Lagerstroemia indica* community. Use manual ground surveys to investigate the spacing between rows and plants and the size of the plants in the *Lagerstroemia indica* community, and formulate measures for the renewal and transformation of the *Lagerstroemia indica* community based on the survey indicators.

[0066] The Laguanmu redevelopment project area on Wild Pineapple Island comprises Laguanmu trees planted in 2014, covering a total area of ​​13 hectares. 2 The original planting ridge width was 20-30m, and the original planting specifications for the timber were 2m×2m. Figure 5 Thinning area (left), clear-cutting area (right); The Laguanmu regeneration and renovation project area in Xinghui Village consists of Laguanmu trees planted in 2010, with a total area of ​​9 hectares. 2 The original planting ridge width was 20-25m, and the planting spacing of the *Ligustrum lucidum* was 1m × 2m. Figure 6 (Left, thinning area; right, clear-cutting area)

[0067] 2. Pack the discarded oyster shells into old fishing nets, each bag weighing approximately 20 kg. After transporting them to the restoration work area, place them 1 meter away from the outer edge of the Laguanmu forest. Figure 2 Specifications, such as Figure 4 Stack them as shown in (Wild Pineapple Island a; Star Village b).

[0068] 3. Restoration work in thinned areas

[0069] 3.1. In the thinning area 5m wide at the outer edge of the forest stand, the pine trees should be cut down in alternating rows, and all felled pine trees should be removed from the restoration work area. The stumps should be less than 10cm above the ground and tightly wrapped and secured with black nutrient film.

[0070] 3.2. Prune all lateral branches of the trees that have not been felled in the thinning zone 5m wide on the outer edge of the forest stand, and remove the pruned branches from the restoration work area.

[0071] 3.3. Dig holes 0.5m×0.5m apart in the direction parallel to the original planting rows, and prepare the land. The hole size is 30cm×30cm×30cm.

[0072] 3.3 Plant 2-year-old red sea olive seedlings with a height of 100cm in the prepared planting hole.

[0073] 3.4 One year later, all remaining timber in the thinning and restoration area shall be felled, and all felled timber shall be removed from the restoration area. Piles less than 10cm above the ground shall be tightly wrapped and secured with black nutrient film.

[0074] 4. Clear-cutting operations

[0075] 4.1 All the clear-cutting trees in the restoration area should be removed, with the stumps less than 10cm high. The stumps should be wrapped tightly with opaque black plastic film to prevent new shoots from sprouting from them.

[0076] 4.2 Dig holes 1m×1m in the direction parallel to the original planting rows and prepare the land. The hole size is 30cm×30cm×30cm.

[0077] 4.3 Plant 1-year-old autumn eggplant seedlings with a height of 60cm in the prepared planting hole.

[0078] 5. Fence

[0079] 5.1 Insert bamboo poles with a diameter of 8cm and a length of 2.5m along the edge of the embankment, inserting them into the mudflat to a depth of 50cm. The bamboo poles should be spaced 2m apart.

[0080] 5.2 Tie the old fishing net to the bamboo pole, with the net 1.8m high and the bottom end close to the ground.

[0081] 6. Maintenance

[0082] Monthly inspections of the renovation and repair work are conducted. Any damaged black plastic film used to wrap the stumps is promptly rewrapped. Any sprouts found on the stumps are immediately stripped of their bark. Damaged saplings are promptly replanted.

[0083] Due to proper measures and effective management, the two remediation areas showed excellent results, with no loss of sediment in the tidal flats, no sprouting of stumps, and a survival rate of over 90% for planted seedlings.

[0084] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for transforming a difficult-to-establish mangrove community in tidal flats, characterized in that, Includes the following steps: S1. Current status survey of mangrove plants: Use drones to survey the appearance, distribution and area of ​​the Laguanmu community; use artificial ground surveys to investigate the spacing between rows and plants and the size of plants in the Laguanmu community; and formulate measures for the renewal and transformation of the Laguanmu community based on the survey indicators. S2. Beach protection and restoration measures: Construct a beach protection dike 1m away from the edge of the Laguanmu forest. S3. Pruning or felling of trees. S31. The work area is divided into two work areas. A 5-meter-wide forest belt is designated as a thinning area in the forest edge area where sediment is easily lost. Other work areas are designated as direct clear-cutting areas. S32. Pruning: Prune the thinning area of ​​the mangroves in alternating rows, remove all lateral branches, increase light in the forest, and provide conditions for the growth of other mangrove plants in the forest. The number of plants pruned is 50% of the mangroves in the thinning area. S33, felling S331. All the clear-cutting trees in the clear-cutting area shall be cut down. The height of the cut tree stumps shall be less than 10cm. The stumps shall be wrapped tightly with opaque black plastic film to prevent new shoots from sprouting from the stumps. S332. Remove the unpruned lateral branches of the pruning trees in the thinning area in alternating rows, with the number of trees removed being 50% of the pruning area's pruning trees; the height of the removed pruning tree stumps should be less than 10cm, and after removal, the stumps should be tightly wrapped with opaque black plastic film to prevent the stumps from sprouting new branches. S333. One year later, all the remaining pruning trees in the thinning area were felled, and the felled tree stumps were wrapped tightly with opaque black plastic film to prevent the stumps from sprouting new branches. S4. Planting mangroves S41. In the Laguan clear-cutting area, based on the tidal flat elevation, select one-year-old native mangrove seedlings and plant them at a size of 1m×1m. S42. In the thinning area of ​​the Laguan tree, select 2-3 year old red sea olive or red mangrove seedlings and plant them at a size of 0.5m×0.5m. S5. Management and maintenance: After the mangrove seedlings are planted, use 10cm×10cm mesh nets to enclose the restoration area along the revetment to prevent marine debris from drifting into the forest. Remove the nets after one year. S6. Effect evaluation, mainly based on the shoreline preservation rate, the sprouting rate of *Lysimachia clethroides*, and the growth of planted seedlings; The main investigation and assessment of the shoreline preservation rate is whether the sediment in the tidal flats of the restoration area has been eroded, resulting in a decrease in the elevation of the tidal flats and degradation of suitable afforestation land. The main investigation into the sprouting rate of the felled trees is whether new shoots sprout from the felled stumps, as the sprouting of shoots from the stumps affects the transformation effect; The survey and evaluation of the growth of planted seedlings mainly includes the survival rate of seedlings and the natural regeneration situation. A survival rate of over 90% for seedlings in thinning areas and over 70% for seedlings in clear-cutting areas can ensure the effectiveness of the transformation.

2. The method for transforming a difficult-to-site tidal flat expatriate mangrove community as described in claim 1, characterized in that, The method for constructing the protective dike in step S2 includes: Use old fishing nets to pack discarded oyster shells, each weighing 15-20 kg, and transport them to the Laguanmu Renovation Area. Stack them in a trapezoidal shape in the direction of tides to form a wave-dissipating and beach protection dike. The dike is 100 cm wide at the bottom, 40 cm wide at the top, and 30 cm high.

3. The method for transforming a difficult-to-site tidal flat expatriate mangrove community as described in claim 1, characterized in that, In step S41, the seedling selection requirements are as follows: the required seedlings need to be cultivated in an environment with a water salinity > 20‰, the diameter of the seedling root ball is 10-12cm, and the height of the seedling is 50-60cm.

4. The method for transforming a difficult-to-site tidal flat expatriate mangrove community as described in claim 1, characterized in that, The seedling selection requirements in step S42 are as follows: the required seedlings need to be cultivated in an environment with a water salinity > 20‰, the soil ball diameter is 20-25cm, the seedling height is > 80cm, and the main stem of the seedling has 3-5 prop roots.

Images