Restoration of Sand Habitats and Dunes on Land
This action comprised the removal of invasive species and the restoration of duneslopes on six locations. Continuous measures to reinforce the elimination of the plants took place in the summer of 2020, and continued in Ystad at Nybrostrand during the winter of 2020/2021.
In Helsingborg, Rosa rugosa was removed at all sites in Hittarp (7000 m2) and Domsten
(10 000 m2) in spring 2019 and spring 2020.
In March 2019, the first sites with Japanese rose (Rosa rugosa) were dug out and restored. The excavator dug a deep hole and placed the rose plants at the bottom of it, covering them with the sand from the deeper parts of the profile. This method turns the dune upside down, placing clean sand, free of roots and with a slightly higher pH, on the surface of the dune.
Early spring 2019 and 2020, an area of approximately 10 000 m2 with Japanese rose was dug up in Domsten and 7 000 m2 in Hittarp. The method applied was decidedly cost efficient and larger areas than expected and applied for could be restored.
The summer after excavating, smaller shoots from root fragments of Japanese rose were manually excavated with a shovel at a low cost and without impact on other newly established vegetation.
Planting stabilizing vegetation has only been needed on a few smaller parts of the sites. Flowering herbs and dune grass settled naturally on the dunes already the first summer. This natural process was not interfered with and there was very little wind erosion. Subsequently, the general decision was not to plant dune grass or lay out any coconut fibre. This conclusion was drawn together with the experts from Lund University involved in the project. Exceptions were made at two spots where the settlement was just next to the excavations. Dune grass was planted on one small site, and a willow fence was put up to prevent wind erosion.
The restored dunes bloom vigorously in the summer and many bumblebees and butterflies have been seen flying between the flowers. Lund University has carried out follow-up inventories of flora and fauna at the sites of restoration. The municipality has also measured heights of the coastal profile in 23 spots before and after actions.
In Bjärred, Lomma, the action was carried out in an area of about 1 700 m2. Reynoutria japonica, Petasites hybridus and Hippophaë rhamnoides were removed. The action turned out to cover a larger area than estimated, due to a larger spread of Petasites hybridus. Before and during the work, the contractor was given information and guidelines about the handling of the species to be removed. A second removal of Petasites hybridus took place in May 2020, in order to remove seedlings that survived the first removal.
Japanese knotweed is present in two parts of the site. The chosen method for removal is "continuous mowing". During the period of March-August 2020, the plants were cut down once a week. They grew approximately 90 cm a week. The largest area was marked out with barrier tape and information boards. It has been enlarged a number of times as the plant has spread sideways by rhizomes.
The removal of Petasites hybridus and Butterbur is successful. The top layer was fractioned and only the parts above ground were removed. The root system was compact but not deep. This approach is a part of the future regular maintenance of all public areas in the municipality. Stabilizing species planted at all sites is completed in Bjärred.
In Ystad, at the site Ystad Sandskog, the park unit's staff together with contractors carried out activities in combating invasive species and limiting expansive species during the winter and spring of 2020, completed in April 2020. Both areas had to be replanted with new plants, practically to tie the soil, and aesthetically, not wanting to leave half finished work.
2 670 m2 of Japanese knotweed was excavated and transported to a waste facility, thrown straight into the furnace for destruction, without a chance that the invasive species end up in the wrong place and thus risk spreading. The ground was levelled and prepared to be mowed. Along the beach walk in an area of 1 950 m2, Aspen trees were sawn down, and young trees and weeds were cleared away on the dune. Stumps and roots were dug up and transported away.
At the site Nybrostrand in Ystad, the intention is to combat Rosa Rugosa. No replanting is expected as there are plenty of beach rye and other beach plants in the immediate vicinity, which are shortly expected to take over the exposed sand and occupy the sand dunes.
The restoration of dune slopes is done at Domsten and Hittarp, placing already washed up macro algae and seagrass at the foot of the dune. These measures were coordinated with maintenance activities at some of the more frequently used beaches, where macro algae is removed on a regular basis. At all sites in Hittarp and Domsten where Japanese rose were excavated, the shape of the dunes was modified, making them less steep and thereby preventing erosion.
These measures were implemented together with the measures of removing hard structures and of shoreface and beach nourishment .
Some worried neighbours along the coast initially questioned the measures, which was bridged with communication and information. Property owners and outdoor life have a benevolent attitude, now that they see the water after the Japanese roses were removed.
In Ystad, where Japanese knotweed were excavated, forest plants wereplanted around the cabins along the road. It beautifies and creates protection, and prevents cars from parking by the side of the road out in the woodland.
Extra careful control is done next to the new plants so that Japanese knotweed does not get established there. The new plants are watered during the dry parts of summer. After the summer, all the planted plants have survived and look healthy. Watering is regular, as well as mowing of grass areas around the plants. Japanese knotweed, which previously constituted a monoculture over the entire surface, has not given up yet and continues to shoot new shoots.
The sand dunes where Aspen was removed, are djusted so that sand should not fall on the beach walk, and the slopes are reinforced with coconut fabric. Furthermore, the sand dunes are planted with beach grass and herbs that naturally belong there.
The progress of the action looks good, as we look forward to the plants on the dunes growing together even more and really binding the sand where it should be, and helping to cover the coconut mat, which is becoming less visible as time goes.
So far, no one has used this method for a coastal stretch adjacent to Öresund for Japanese knot weed growing in seaweed banks and spreading through erosion. The geophysical circumstances are very special as the sea level in the sound is changing quickly and quite unpredictably due to changing coastal streams. This will create another type of erosion than normally through powerful winds, waves, and tidal water. At the same time, the area is densely populated and land use often maximized. The project demonstrates that even with narrow stretches of coastal land, adjacent to important infrastructure and buildings, we might be able to improve the ecosystem services and biodiversity immensely on site with nature-based solutions.