17.5 Climate Change Threats and Worrying Aspects
One of the consequences of climate change that alpine plants and habitats will have
to face is the potential occurrence of milder winters with less snow. The length and
depth of snow cover, correlated with low temperature is considered as a key
climatic element in alpine areas (Ozenda and Borel 1991) and the plants from the
alpine level, such as the hekistothermophytes and the psychrothermophytes from
Bucegi mountains, are sensitive to these factors.
At the same time, a reduction in the duration of snow coverage and amount of
snowfall will affect the regeneration of plants from the high elevation of Bucegi
mountains, which depend on vernalisation. According to Ozenda and Borel (1991),
the species living in snow beds will be the most vulnerable to warming.
Plant species can respond to changes of the climatic conditions in different ways:
genetic adaptation, species extinction, biological invasion (Huntley 1991). Up to
now we have minimal empirical evidence of how the alpine plants from Bucegi
mountains will react to environmental changes.
However, it is worrying that the dominant species of Festuca supina grasslands
and also the majority of the other present species including rare and endemic plants
are mostly hemicryptophyte and chamaephyte, and microthermic dependent.
Another worrying aspect is related to the upward migration process of plants
which can produce changes in the vegetation from the existing habitats and can
affect the cryophilous plants. An upward migration of some species from lower
altitudes seeking climatic conditions suitable for their life functions was also
observed for the habitat type 6150 from Bucegi Natural Park. This type of response
to the effects of climate change has also been reported in the Alps (Theurillat
et al. 1998; Pauli et al. 2003).
The alpine habitats from Bucegi National Park are subject to various influences
of human activity. As far as grasslands are concerned, grazing has a particularly
significant impact and should be taken into account because both the dominant
plants in the studied habitat type, and the associated species are oligotrophic and
sensitive to eutrophication. According the evaluation from the Management Plan of
the Bucegi Natural Park, chapter IV (Administrat ¸ia Parcului Natural Bucegi 2011),
pastures and meadows in Bucegi Natural Park have different amounts of livestock
that often exceed the optimum number of units for grazing land, set at 0.30 LUs/ha.
Intense grazing by various livestock (sheep, horses, goats, cows) is a source of
intense eutrophication and of soil quality degradation, associated with
ruderalisation (Donit ¸a ˘ et al. 2005), a process that can affects the integrity of Festuca
supina grasslands. The emergence of early and warm springs, allows the prolonging
of the grazing period and for the grazing to start at an earlier time, affecting the
regeneration and breeding capacity of spring plants and increasing soil nutrients.
In these circumstances, the question is: “How will alpine habitats from Bucegi
mountains respond to climate change?” Certainly each habitat react rather individually, but the current structure of the plant communities and the ecological spectrum of the component species may offer some indication. In an environment
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A. Sa ˆrbu et al.
One of the consequences of climate change that alpine plants and habitats will have
to face is the potential occurrence of milder winters with less snow. The length and
depth of snow cover, correlated with low temperature is considered as a key
climatic element in alpine areas (Ozenda and Borel 1991) and the plants from the
alpine level, such as the hekistothermophytes and the psychrothermophytes from
Bucegi mountains, are sensitive to these factors.
At the same time, a reduction in the duration of snow coverage and amount of
snowfall will affect the regeneration of plants from the high elevation of Bucegi
mountains, which depend on vernalisation. According to Ozenda and Borel (1991),
the species living in snow beds will be the most vulnerable to warming.
Plant species can respond to changes of the climatic conditions in different ways:
genetic adaptation, species extinction, biological invasion (Huntley 1991). Up to
now we have minimal empirical evidence of how the alpine plants from Bucegi
mountains will react to environmental changes.
However, it is worrying that the dominant species of Festuca supina grasslands
and also the majority of the other present species including rare and endemic plants
are mostly hemicryptophyte and chamaephyte, and microthermic dependent.
Another worrying aspect is related to the upward migration process of plants
which can produce changes in the vegetation from the existing habitats and can
affect the cryophilous plants. An upward migration of some species from lower
altitudes seeking climatic conditions suitable for their life functions was also
observed for the habitat type 6150 from Bucegi Natural Park. This type of response
to the effects of climate change has also been reported in the Alps (Theurillat
et al. 1998; Pauli et al. 2003).
The alpine habitats from Bucegi National Park are subject to various influences
of human activity. As far as grasslands are concerned, grazing has a particularly
significant impact and should be taken into account because both the dominant
plants in the studied habitat type, and the associated species are oligotrophic and
sensitive to eutrophication. According the evaluation from the Management Plan of
the Bucegi Natural Park, chapter IV (Administrat ¸ia Parcului Natural Bucegi 2011),
pastures and meadows in Bucegi Natural Park have different amounts of livestock
that often exceed the optimum number of units for grazing land, set at 0.30 LUs/ha.
Intense grazing by various livestock (sheep, horses, goats, cows) is a source of
intense eutrophication and of soil quality degradation, associated with
ruderalisation (Donit ¸a ˘ et al. 2005), a process that can affects the integrity of Festuca
supina grasslands. The emergence of early and warm springs, allows the prolonging
of the grazing period and for the grazing to start at an earlier time, affecting the
regeneration and breeding capacity of spring plants and increasing soil nutrients.
In these circumstances, the question is: “How will alpine habitats from Bucegi
mountains respond to climate change?” Certainly each habitat react rather individually, but the current structure of the plant communities and the ecological spectrum of the component species may offer some indication. In an environment
264
A. Sa ˆrbu et al.