(Cioca ˆrlan 2011). By means of management measures, adaptation is undertaken in
order to reduce potential impacts of climate change on DDBR habitats.
18.2 Methods
The spreading potential of invasive species was analysed by their present features
of adaptation, plant community qualitative indices (Braun-Blanquet scale) and
annual climatic values (temperature, precipitations). The time-frame 1961–2007
data was used from the eastern (Sf. Gheorghe – Black Sea shore) and western
(Tulcea) meteorological stations located in DDBR. The obtained data was compared to the reference (Sanda and Arcus ¸ 1999; Hanganu et al. 2002; Cioca ˆrlan
2011). Subsequently, the data was interpreted by means of mapping software
ArcMap 9.1 and presented on a digital map.
18.3 Results: DDBR Habitats and Invasive Plant Species
Presently, 180 plant communities have been reported within DDBR (Sanda and
Arcus ¸ 1999; Hanganu et al. 2002), integrated within 29 habitats according to the
European Habitats Directive (92/43/EEC). A list of 168 alien plant species, based
on references and field research done during 2009–2011, has recently been compiled (Anastasiu 2011). Twenty-one plant communities mainly consisting of alien
plants identified in the field are listed in Table 18.1.
Regarding the impact of alien plant species on Natura 2000 habitats and its spreading
potential, five habitats from DDBR revealed the following: the annual vegetation on
drift lines of habitat 1210 is strongly modified by the presence of Xanthium italicum;
habitat 1310 Salicornia and other annuals colonising mud and sand are invaded by
Symphyotrichium ciliatum and Xanthium italicum (up to 40 % coverage) at Sacalin
island and the Sulina area; habitat 1410 Mediterranean salt meadows, characterised by
the presence of Juncus maritimus and Juncus littoralis, is in a very good state in
Sf. Gheorghe area, but strongly overrun by Elaeagnus angustifolia in Sulina and invaded
by Ambrosia artemisiifolia at Sacalin island; 1530* Ponto-Pannonic salt-steppes and
salt-marshes is only rarely invaded by Amaranthus blitoides or Amaranthus blitum
subsp. emarginatus; habitat 2110, Embryonic shifting dunes, is strongly modified by
Xanthium italicum often with A-D 1 and 100 % frequency, Conyza canadensis, Cuscuta
campestris and Amorpha fruticosa (Anastasiu 2011).
The most important element in DDBR is the hydrological system (branches,
channels, and lakes). In other words, water circulation and distribution are at the
core of this wetland. While aquatic habitats are invaded by Azolla filiculoides and
Elodea nuttallii, which competes against aquatic communities (Anastasiu
et al. 2007), riparian and alluvial habitats are invaded especially by Amorpha
fruticosa, which often forms the monodominant communities Fraxinus
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order to reduce potential impacts of climate change on DDBR habitats.
18.2 Methods
The spreading potential of invasive species was analysed by their present features
of adaptation, plant community qualitative indices (Braun-Blanquet scale) and
annual climatic values (temperature, precipitations). The time-frame 1961–2007
data was used from the eastern (Sf. Gheorghe – Black Sea shore) and western
(Tulcea) meteorological stations located in DDBR. The obtained data was compared to the reference (Sanda and Arcus ¸ 1999; Hanganu et al. 2002; Cioca ˆrlan
2011). Subsequently, the data was interpreted by means of mapping software
ArcMap 9.1 and presented on a digital map.
18.3 Results: DDBR Habitats and Invasive Plant Species
Presently, 180 plant communities have been reported within DDBR (Sanda and
Arcus ¸ 1999; Hanganu et al. 2002), integrated within 29 habitats according to the
European Habitats Directive (92/43/EEC). A list of 168 alien plant species, based
on references and field research done during 2009–2011, has recently been compiled (Anastasiu 2011). Twenty-one plant communities mainly consisting of alien
plants identified in the field are listed in Table 18.1.
Regarding the impact of alien plant species on Natura 2000 habitats and its spreading
potential, five habitats from DDBR revealed the following: the annual vegetation on
drift lines of habitat 1210 is strongly modified by the presence of Xanthium italicum;
habitat 1310 Salicornia and other annuals colonising mud and sand are invaded by
Symphyotrichium ciliatum and Xanthium italicum (up to 40 % coverage) at Sacalin
island and the Sulina area; habitat 1410 Mediterranean salt meadows, characterised by
the presence of Juncus maritimus and Juncus littoralis, is in a very good state in
Sf. Gheorghe area, but strongly overrun by Elaeagnus angustifolia in Sulina and invaded
by Ambrosia artemisiifolia at Sacalin island; 1530* Ponto-Pannonic salt-steppes and
salt-marshes is only rarely invaded by Amaranthus blitoides or Amaranthus blitum
subsp. emarginatus; habitat 2110, Embryonic shifting dunes, is strongly modified by
Xanthium italicum often with A-D 1 and 100 % frequency, Conyza canadensis, Cuscuta
campestris and Amorpha fruticosa (Anastasiu 2011).
The most important element in DDBR is the hydrological system (branches,
channels, and lakes). In other words, water circulation and distribution are at the
core of this wetland. While aquatic habitats are invaded by Azolla filiculoides and
Elodea nuttallii, which competes against aquatic communities (Anastasiu
et al. 2007), riparian and alluvial habitats are invaded especially by Amorpha
fruticosa, which often forms the monodominant communities Fraxinus
268
M. Doroftei and P. Anastasiu