Database release:
SDF
NATURA 2000 - STANDARD DATA FORM

For Special Protection Areas (SPA),
Proposed Sites for Community Importance (pSCI),
Sites of Community Importance (SCI) and
for Special Areas of Conservation (SAC)

TABLE OF CONTENTS

1. SITE IDENTIFICATION

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1.1 Type

B

1.2 Site code

SE0110385

1.3 Site name

Arholma-Idö

1.4 First Compilation date

2013-10

1.5 Update date

-

1.6 Respondent:

Name/Organisation:Länsstyrelsen i Stockholms län
Address:               
Email:stockholm@lansstyrelsen.se
Date site proposed as SCI:2013-10
Date site confirmed as SCI:2014-12
Date site designated as SAC: No data
National legal reference of SAC designation: No data

2. SITE LOCATION

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2.1 Site-centre location [decimal degrees]:

Longitude:19.130000
Latitude:59.804100

2.2 Area [ha]

248.5000

2.3 Marine area [%]

2.9300

2.4 Sitelength [km]:

0.00

2.6 Biogeographical Region(s)

Boreal (0.00 %) Marine Baltic Sea (2.93 %)

3. ECOLOGICAL INFORMATION

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3.1 Habitat types present on the site and assessment for them

Annex I Habitat types Site assessment
Code PF NP Cover [ha] Cave [number] Data quality A|B|C|D A|B|C
      RepresentativityRelative SurfaceConservationGlobal
1630  info      1.3  0.00 
6210  info  X     2.6  0.00 
6270  info      0.5  0.00 
6410  info      0.7  0.00 
6530  info      5.5  0.00 
9010  info      38  0.00 
9070  info      22  0.00 
  • PF: for the habitat types that can have a non-priority as well as a priority form (6210, 7130, 9430) enter "X" in the column PF to indicate the priority form.
  • NP: in case that a habitat type no longer exists in the site enter: x (optional)
  • Cover: decimal values can be entered
  • Caves: for habitat types 8310, 8330 (caves) enter the number of caves if estimated surface is not available.
  • Data quality: G = 'Good' (e.g. based on surveys); M = 'Moderate' (e.g. based on partial data with some extrapolation); P = 'Poor' (e.g. rough estimation)

3.2 Species referred to in Article 4 of Directive 2009/147/EC and listed in Annex II of Directive 92/43/EEC and site evaluation for them

Species Population in the site Site assessment
G Code Scientific Name S NP T Size Unit Cat. D.qual. A|B|C|D A|B|C
      MinMax  Pop.Con.Iso.Glo.
P1419Botrychium simplex    50  50  shoots     
  • Group: A = Amphibians, B = Birds, F = Fish, I = Invertebrates, M = Mammals, P = Plants, R = Reptiles
  • S: in case that the data on species are sensitive and therefore have to be blocked for any public access enter: yes
  • NP: in case that a species is no longer present in the site enter: x (optional)
  • Type: p = permanent, r = reproducing, c = concentration, w = wintering (for plant and non-migratory species use permanent)
  • Unit: i = individuals, p = pairs or other units according to the Standard list of population units and codes in accordance with Article 12 and 17 reporting (see reference portal)
  • Abundance categories (Cat.): C = common, R = rare, V = very rare, P = present - to fill if data are deficient (DD) or in addition to population size information
  • Data quality: G = 'Good' (e.g. based on surveys); M = 'Moderate' (e.g. based on partial data with some extrapolation); P = 'Poor' (e.g. rough estimation); VP = 'Very poor' (use this category only, if not even a rough estimation of the population size can be made, in this case the fields for population size can remain empty, but the field "Abundance categories" has to be filled in)

3.3 Other important species of flora and fauna (optional)

Species

Population in the site

Motivation

Group CODE Scientific Name S NP Size Unit Cat. Species Annex Other categories
     MinMax C|R|V|PIVVABCD
  • Group: A = Amphibians, B = Birds, F = Fish, Fu = Fungi, I = Invertebrates, L = Lichens, M = Mammals, P = Plants, R = Reptiles
  • CODE: for Birds, Annex IV and V species the code as provided in the reference portal should be used in addition to the scientific name
  • S: in case that the data on species are sensitive and therefore have to be blocked for any public access enter: yes
  • NP: in case that a species is no longer present in the site enter: x (optional)
  • Unit: i = individuals, p = pairs or other units according to the standard list of population units and codes in accordance with Article 12 and 17 reporting, (see reference portal)
  • Cat.: Abundance categories: C = common, R = rare, V = very rare, P = present
  • Motivation categories: IV, V: Annex Species (Habitats Directive), A: National Red List data; B: Endemics; C: International Conventions; D: other reasons

4. SITE DESCRIPTION

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4.1 General site character

Habitat class % Cover
N052.00
N071.00
N107.00
N146.00
N151.00
N166.00
N1739.00
N1937.00
N231.00

Total Habitat Cover

100

Other Site Characteristics

Like most islands in the Stockholm archipelago Arholma and Idö are dominated by coniferous forest, largely on bare bedrock. Both islands have been inhabited for several hundreds of years, with fishery and stock-breeding as the most important bases of livelihood. Around the old settlements there is an agricultural landscape characterized by a small scale mosaic of arable fields, pastures, sea-shore meadows and former wooded meadows. To a large extent the latter nowadays have developed into hardwood-dominated deciduous forest. The most densely inhabited parts are situated outside the Natura site, on Arholma. The only remaining farm in operation, Simesgården, is however situated within the Natura site, on Arholma. Almost all pastures and arable fields on the two islands are farmed by Simesgården.

4.2 Quality and importance

Lime-rich soils contribute to a herb-rich vegetation including good populations of several orchids. Former land-use as wooded meadows with numerous pollards has formed semi-open hardwood forests, although they during the last decades mostly have become densely overgrown with bushes and a young tree-layer. Ash is the most common of the old trees in the hardwood-forests, but maple is also widespread while oak is nearly absent due to extensive use in ship-building in the nineteenth century. Some stands have a dense bush-layer of hazel. Along flat parts of the shore there are narrow coastal meadows, mostly overgrown with tall grasses and reeds, partly also by alder. Due to the lime-rich soil they are still species-rich and can easily be restored by intensified grazing. In attempt to restore the wooded meadows smaller areas near Simesgården and the settlement on Idö have been thinned and pollarding have been introduced on young ash-trees as well as reintroduced on old, formerly pollarded ash-trees. Close to the shore on the southernmost head of Idö grows the annex II fern Botrychium simplex. Good years up to 130 shoots have been counted on a few dozens of square-meters of dry grass-land. During the last decades forestry has had low intensity, resulting in dominantly mature forest with a significant degree of old-growth forest. Other parts, where the tree-layer were established before the era of modern forestry practices, have retained structures that was formed by gracing as well as the diversified, but low intensive, use of wood by self-subsistent household. The present distribution of grassland Natura habitats is rather limited. The main importance of the site is the good potential to restore herb-rich grasslands and hardwood-stands with structure of wooded meadow. The risk of worsening the effects of ash dieback, Hymenoscyphus pseudoalbidus, makes it very uncertain whether pollarding any longer is wise conservation management practice. Full restoration back to original habitat, wooded meadow, therefore should await better knowledge on ash dieback and pollarding.

4.3 Threats, pressures and activities with impacts on the site

The most important impacts and activities with high effect on the site

Negative Impacts
RankThreats and pressures [code]Pollution (optional) [code]inside/outside [i|o|b]
HA04.03b
HG05.07i
MK04.03b
Positive Impacts
RankActivities, management [code]Pollution (optional) [code]inside/outside [i|o|b]
LA04.02.05b

Rank: H = high, M = medium, L = low
Pollution: N = Nitrogen input, P = Phosphor/Phosphate input, A = Acid input/acidification,
T = toxic inorganic chemicals, O = toxic organic chemicals, X = Mixed pollutions
i = inside, o = outside, b = both

5. SITE PROTECTION STATUS

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5.1 Designation types at national and regional level:

Code Cover [%]
SE02100.00

5.2 Relation of the described site with other sites:

Designated at national or regional level:

Type code Site name Type Cover [%]
SE02Lidö naturreservat/0.00

Designated at international level:

Type Site name Type Cover [%]
Other Lidö naturreservat/0.00

6. SITE MANAGEMENT

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6.1 Body(ies) responsible for the site management:

Organisation:Länsstyrelsen i Stockholms län
Address:
Email:stockholm@lansstyrelsen.se
Organisation:Skärgårdsstiftelsen
Address:
Email:kansliet@skargardsstiftelsen.se

6.2 Management Plan(s):

An actual management plan does exist:

X
Yes Name: Arholma-Idö
Link: http://skyddadnatur.naturvardsverket.se/

No, but in preparation
No

6.3 Conservation measures (optional)

Relevant areas have periodically time been grazed with low intensity for several decades. Tree- and bush-layer have nevertheless been considerable overgrown. The intensity of grazing is limited by available live-stock although forestry have been permitted.

 

7. MAP OF THE SITE

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INSPIRE ID:SE.SWEPA.SE0110385
Map delivered as PDF in electronic format (optional)
Yes
No

SITE DISPLAY