the lowest mean multi-annual precipitation amounts; the highest precipitation
amounts fallen in short intervals (24 and 48 h) due to extreme weather events;
extended periods of dryness and drought phenomena, thus ranking the area among
the first three in the country in terms of frequency, duration and intensity; high wind
speeds and frequencies, this yields the highest wind power energy in the country;
high degree of vulnerability to strong winds (!16 m/s); increased frequency and
intensity of dangerous climatic events (e.g. heavy rains, fog, blizzards).
Changing climatic conditions influence three essential elements of invasion: the
source location, the pathway, and the destination (Dangles et al. 2008; Hellmann
et al. 2008). Species that tolerate a wide range of climatic conditions could become
the most successful invaders (Taush 2008). For example, precipitation variations
could cause water-demanding/resistant species to outcompete one another
(Fig. 18.2). The average annual precipitation of DDBR decreases from west (Tulcea
– 438.4 mm) to east (Sf. Gheorghe – 403.6 mm).
From the perspective of alien’s bio-geographical origin, rising temperatures would
allow some species of Mediterranean origin to spread northwards and enhance the
winter survival chances of some other organisms (Dragota ˘ et al. 2011). Phenological
stages are sensitive to temperature. It is more likely for annual plants to flower
earlier than it is for perennials, and more likely for insect-pollinated plants than for
wind-pollinated ones (Fitter and Fitter 2002).
Various flowering phases have been registered for the same species in the same
period of time but at different locations (Tulcea and Sf.Gheorghe) within DDBR
(Fig. 18.3). At the sea side flowering phases are now occurring earlier. The average
annual temperature in Tulcea is 11
C and in Sf. Gheorghe 12
C (Dragota ˘
et al. 2011). Monthly average of daily extreme temperatures have a significant
role in the distribution of different phenological phases, as they are calculated from
instantaneous values at different moments of the day, measured with maximumminimum thermometers representing the true contrast between day and night.
Table 18.2 (continued)
Invasive species
Plant community (Natura 2000
habitat type)
Qualitative Index
Xanthium
italicum
1: Argusietum sibiricae (1210);
1: AD +; 2: AD +; 3: AD +; 4: AD +; 5:
AD + À3, F 10–100 %; 6: AD +; 7:
AD +; 8: AD + À3, F 100 %;
2: Atripliceto hastatae-Cakiletum
euxinae (1210);
3: Convolvuletum persici (1210);
4: Acorelletum pannonici (1310);
5: Elymetum gigantei (2110);
6: Suaedo-Kochietum hirsutae
(1310);
7: Calamagrostio epigeiHippophae ¨tum rhamnoides
(2160);
8: Suaedeto maritimae (1310)
Xanthium
spinosum
Trifolio fragifero-Cynodontetum
(1530*)
AD +, F < 10 %
18 Potential Impacts of Climate Change on Habitats and Their Effects. . .
271
amounts fallen in short intervals (24 and 48 h) due to extreme weather events;
extended periods of dryness and drought phenomena, thus ranking the area among
the first three in the country in terms of frequency, duration and intensity; high wind
speeds and frequencies, this yields the highest wind power energy in the country;
high degree of vulnerability to strong winds (!16 m/s); increased frequency and
intensity of dangerous climatic events (e.g. heavy rains, fog, blizzards).
Changing climatic conditions influence three essential elements of invasion: the
source location, the pathway, and the destination (Dangles et al. 2008; Hellmann
et al. 2008). Species that tolerate a wide range of climatic conditions could become
the most successful invaders (Taush 2008). For example, precipitation variations
could cause water-demanding/resistant species to outcompete one another
(Fig. 18.2). The average annual precipitation of DDBR decreases from west (Tulcea
– 438.4 mm) to east (Sf. Gheorghe – 403.6 mm).
From the perspective of alien’s bio-geographical origin, rising temperatures would
allow some species of Mediterranean origin to spread northwards and enhance the
winter survival chances of some other organisms (Dragota ˘ et al. 2011). Phenological
stages are sensitive to temperature. It is more likely for annual plants to flower
earlier than it is for perennials, and more likely for insect-pollinated plants than for
wind-pollinated ones (Fitter and Fitter 2002).
Various flowering phases have been registered for the same species in the same
period of time but at different locations (Tulcea and Sf.Gheorghe) within DDBR
(Fig. 18.3). At the sea side flowering phases are now occurring earlier. The average
annual temperature in Tulcea is 11
C and in Sf. Gheorghe 12
C (Dragota ˘
et al. 2011). Monthly average of daily extreme temperatures have a significant
role in the distribution of different phenological phases, as they are calculated from
instantaneous values at different moments of the day, measured with maximumminimum thermometers representing the true contrast between day and night.
Table 18.2 (continued)
Invasive species
Plant community (Natura 2000
habitat type)
Qualitative Index
Xanthium
italicum
1: Argusietum sibiricae (1210);
1: AD +; 2: AD +; 3: AD +; 4: AD +; 5:
AD + À3, F 10–100 %; 6: AD +; 7:
AD +; 8: AD + À3, F 100 %;
2: Atripliceto hastatae-Cakiletum
euxinae (1210);
3: Convolvuletum persici (1210);
4: Acorelletum pannonici (1310);
5: Elymetum gigantei (2110);
6: Suaedo-Kochietum hirsutae
(1310);
7: Calamagrostio epigeiHippophae ¨tum rhamnoides
(2160);
8: Suaedeto maritimae (1310)
Xanthium
spinosum
Trifolio fragifero-Cynodontetum
(1530*)
AD +, F < 10 %
18 Potential Impacts of Climate Change on Habitats and Their Effects. . .
271