Abstract: Common juniper
Juniperus communis L. formations occurring on oligotrophic sandy substrates in central European lowlands are of high ecological value, but although once widespread, they have disappeared over most of Europe. In suboceanic areas of Central Europe, the
Vaccinio−Juniperetum communis Passarge & G. Hofmann 1968 association is recognized. In addition, the
Helichryso−Juniperetum association was published by Barkman as its subcontinental vicariant, occurring in central and north−eastern parts of Poland. However, according to the International Code of Phytosociological Nomenclature – ICPN, the vicariant was not valid due to insufficient phytosociological documentation. In Poland, common juniper shrub patches are usually recognized as a plant community with
Juniperus communis. The phytosociological classification of plant communities in Europe identifies the
Vaccinio−Juniperion communis Passarge in Passarge et G. Hofmann 1968 alliance, containing European lowland juniper scrub communities. Lowland juniper patches are protected as Natura 2000 habitat type 5130. However, the subcontinental vicariant does not have a valid phytosociological indicator. This article’s aims are to document new patches of subcontinental juniper scrub, validate the
Helichryso−Juniperetum association identified by Barkman, describe the internal variation of the syntaxon, and provide an overview of the distribution of juniper scrub and its dynamics in central and north−eastern Poland. To accomplish these objectives, study sites were established in the Nowa Warszawa Forest (NWF), located on the edge of Warsaw, and in the Niepust range in Kampinos National Park (KNP). Fieldwork was conducted in 2021. Juniper scrub was documented with 17 relevés. The old association name was not considered applicable due to the low frequency of
Helichrysum arenarium and its absence in the designated type. Thus,
Solidagini virgaureae−Juniperetum communis was instead typified. The diagnostic value of species differential at the association level was reviewed by comparing species frequencies with the synoptic table of
Vaccinio−Juniperetum from Mecklenburg−Vonpommerns. Two new subassociations and a third provisional subassociation were distinguished and typified. The
S−J cladonietosum mitis is characterised by a large share of grassland species, higher than in the
S−J typicum. The provisional
S−J molinietosum caeruleae is characterised by the presence of
Molinia caerulea. The large number of species differential at the association level within the subassociations indicates that they all belong to
Solidagini virgaureae−
Juniperetum communis. In our opinion, they should be included in the 5130 Natura 2000 habitat type. Juniper scrub formations are rapidly declining in central and north−eastern Poland. Their active conservation has already started in the Ciosny nature reserve and KNP.
Key words: Helichryso−Juniperetum,
Juniperus communis, lichens, Natura 2000, 5130 habitat, Warsaw, Kampinos Forest