Freshwater Pearl Mussel and its habitats (LIFE04/NAT/SE/00023)

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Freshwater Pearl Mussel and its habitats (LIFE04/NAT/SE/00023)


Factsheet: Sweden- Restoration of the Freshwater Pearl Mussel and its habitats (LIFE04/NAT/SE/000231)

General
Country SE
River Name 21 different water courses
Site Name Sweden- Restoration of the Freshwater Pearl Mussel and its habitats (LIFE04/NAT/SE/000231)
River Characterisation
    River typology
    Location (Lat Lon) 59.1421349497426, 12.1728515625
    Altitude lowland: < 200 m
    Catchment area small: 10 - 100 km2
    Geology
    National code/
    River type name
    Hydromorphological quality elements

    Biological quality elements
    Ecosystem Services
    EU Directives
    Pressures
    Measures
    Other
    Project size -1
    Approximate costs > 1 000 000 Euros
    Synergy
    Status Realised
    Period of realization 2004-2009
    Evaluation Hydromorphological and ecological changes
    Implemented by WWF Sweden


    Key features of the case study

    Drivers

    Main concerns: Ecological concerns
    Legal requirements: Natura 2000
    Opportunities: Broader management plan (Swedish national conservation plan)

    95 % of the Fresh Pearl water mussel population in Central Europe has fallen. The specie is classified by IUCN as endangered and is included in the EU habitat directive. Sweden is home to a large part of the remaining population (a core area) and therefore have an international responsibility for the species’ long-term survival’.

    Pressures

    Hydrological regime modification
    Artificial barries upstream from the site
    Artificial barries downstream from the site
    Alteration of instream habitats
    Sedimentation and sediment input
    Nutrients pollution
    Micropollutants
    Acidification

    Humans activities

    Mainly forestry
    Agriculture

    Global objectives

    Species enhancement and habitats improvement were the main objectives of the project by developing and testing methods to achieve a favourable conservation status for the freshwater pearl mussel (Margaritifera margaritifera) in Sweden. However, freshwater mussel was not the only target specie of the project. A freshwater mussel population decrease highlights a deterioration of the environnment, the improvement of freshwater mussels habitats will thus benefit other aquatic species such as host fish.

    Specific goals (process oriented)

    In order to achieve the conservation of Margaritifera margaritifera, the project aimed to :
    1. eliminate the migration obstacles to host fish along ten watercourses
    2. improve the river bed in eight watercourses
    3. manage the banks along two small rivers
    4. Re-introduce young mussels (test in one stream)

    Site description

    Measures selection

    Description

    Several measures were implemented aiming to restore the Margaritifera margaritifera population using different means:

    1. Water flow quantity improvement
    Repairing a dam that regulates the water flow into the stream Lillsjöbäcken to avoid water shortage in summer

    2. Sediment flow quantity improvement
    Blocking of 17 ditches with wood and ground materials to reduce negative impact from siltation

    3. Longitudinal connectivity improvement
    Removing obstacles
    Fixing incorrectly placed road culverts
    Building bypasses around migration obstacles

    4. In-channel structure and substrate improvement
    Deposit of gravel and small stones in fast-flowing river sections (restoration of around 1300 m2 of stream grounds across eight sites through )

    5. Riparian zone improvement
    Removal of spruce and other vegetation which impact on streams, in favour of deciduous trees along two shoreline sites (a total of 4.5 hectares buffer zone have been thinned and cleared along the streams Sollumsån and Bratteforsån)

    6. Specie enhancement
    Reintroduction of freshwater pearl mussels (1 000 mussels collected from a nearby watercourse in the same basin.)

    Constraints

    Every measures were not implemented as foreseen due to different constraints. Some actions were actually compromised due to historic cultural values, and one action was postponed due to disagreement with landowner. Furthermore, the planned deposit of gravel was less than anticipated due to research which revealed lower need.

    Success criteria

    The mussel recruitment is expected within the coming 10–20 years. None measurable criteria were actually set in the frame of the LIFE project due its too short time frame. However, measurable criteria with regards to the Margaritifera margaritifera recruitment have been set in the frame of the swedish national conservation plan (XX).

    Ecological response

    Other biota

    Due to the complex life cycle of the freshwater mussel, it will take 5-10 years (at least) before it is possible to assess the real conservation impact of the implemented actions. However, the first monitoring highlights an increase of freshwater pearl mussel larvae on the fish geals.

    Hydromorphological response

    Monitoring before and after implementation of the project

    Before

    Biotic, chemistry and hydromorphologic studies were carried before restoration in order to select suitable sites by evaluating the viability and the size of the population:

    1. BOTIC: Monitoring freshwater pearl mussel and host fish. Electricfishing were carried to evaluate the host fish population (and to assess mussel larvae parasites on fish geals) and mussels inventories were done by using an Aquascope or peep box (monitoring according to the standard method recommended by the Swedish Environmental Protection Agency)

    2. HYDROMORPHOLOGIC: Monitoring riverbed substrates by documenting the rate of sedimentation of riverbeds, the distribution of substrate size from silt to boulder, the turbidity of the water and the level of sedimentation (June-September)

    3. WATER QUALITY (especially pH)

    After

    Those assessments were also carried after restoration. The post-monitoring, carried on by the County Administrative Board, still runs for the Margaritifera margaritifera population and also electric fishing. Besides, the University of Karlstad is currently monitoring the sedimentation of the river beds. Sedimentation samples were taken before and after the restoration to see whether the siltation/sedimentation has decreased. This monitoring aims to evaluate the success and efficiency of the restoration and of land use change (bad forestry management is a common source to sedimentation).

    Reference site

    Socio-economic aspects

    Contact person within the organization

    Name : Sofi Alexanderson
    Role : Project manager/coordinator
    OrganisationName : WWF Sweden
    OrganisationType : NGO-Foundation
    Phone-Number : 0046 6247449
    Email : sofi.alexanderson@wwf.se

    Extra background information

    Restoration of freshwater pearl mussel Streams (Degerman et al., 2009): http://www.wwf.se/source.php/1257735/Restoration%20of%20FPM%20streams.pdf)

    National conservation plan : http://www.naturvardsverket.se/Documents/publikationer/620-5429-5.pdf (swedish)

    References

    Website : www.wwf.se/fpm

    Reports :

    LIFE Web Summary: http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=home.createPage&s_ref=LIFE04%20NAT/SE/000231&area=1&yr=2004&n_proj_id=2616&cfid=29961&cftoken=85a2d807f56210a4-00DBC7AC-BB24-6BD8-882160155D9C1C19&mode=print&menu=false

    LIFE Layman’s report : http://www.wwf.se/source.php/1268431/Freshwater_pearl_mussel.pdf

    LIFE Progress Report http://www.wwf.se/source.php/1164065/Progress%20report%202007%20LIFE04NATSE000231.pdf

    Related Measures

    Related Pressures