environmental characteristics of rock ptarmigan’s territory. Additionally, more
detailed vegetation sampling will be done in feeding and nesting habitats. With
the use of aerial photography, the vegetation changes – succession in the rock
ptarmigan’s habitat will be detected.
The human impacts will be evaluated indirectly, due to the presence of Corvidspecies, the number of accommodations in mountain huts, and by direct observations of human disturbances in the field.
12.4 Expected Results of Climate Change Impacts
on Rock Ptarmigan Population
Like in other Alpine countries (e.g. Beniston 1997; Keiler et al. 2010), changes of
some climate factors were already observed in Slovenian Alps. The increase of
mean annual, minimal and maximal temperatures in the period from 1961 to 2011 is
statistically significant in all analysed meteorological stations in TNP
(547–2,514 m a.s.l.). Furthermore, the negative trends in the number of days with
snow cover during snow season were also noted (C ˇ repins ˇek et al. 2012). Considering
those environmental changes, we expect alterations in population and distribution of
rock ptarmigan, as well as changes of its habitat. In particular, due to its strong
dependence on weather conditions during the breeding season, the breeding phenology and breeding success are expected to be largely effected.
Following the effects of climate changes which have already been detected in some
alpine grassland vegetation (Cannone et al. 2007; Ko ¨rner 1999; Keller et al. 2000), we
predict accelerating plant succession by which the proportion of woody species will
increase. Additionally, the tree-line will shift upwards to higher altitudes. This process
is expected to proceed faster in dry habitats on carbonate ground, which is widespread
in the Slovenian Alps. Similar results are presumed in species distribution modelling
where due to increasing temperatures during the breeding season, potential habitats
are expected to decrease by up to two-thirds of area by the year 2070 (Revermann
et al. 2012). Such vegetation changes could reduce suitable habitats for rock ptarmigan
resulting in the greater isolation of already fragmented populations (Storch 2007) and
consequently lower gene flow exchange between them.
Additionally, the increase overlap between rock ptarmigan and other grassland
bird and/or small mammal species, causing greater competition between them, is
expected. So far, only few published data on interactions between rock ptarmigan
and other grassland species exist. The evidence about alpine marmot predation on
rock ptarmigan nests were reported from the Alps (Jordana et al. 2006 cited in
Figueroa et al. 2009), whereas the results from Pyrenees suggest that such interaction is only a sporadic event (Figueroa et al. 2009).
Finally, the loss of appropriate habitats with increasing human disturbances,
lower breeding success, as well as greater interspecific competition could affect the
viability of rock ptarmigan population in a level that cause the decline or extinction
of local populations.
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T. Petras
detailed vegetation sampling will be done in feeding and nesting habitats. With
the use of aerial photography, the vegetation changes – succession in the rock
ptarmigan’s habitat will be detected.
The human impacts will be evaluated indirectly, due to the presence of Corvidspecies, the number of accommodations in mountain huts, and by direct observations of human disturbances in the field.
12.4 Expected Results of Climate Change Impacts
on Rock Ptarmigan Population
Like in other Alpine countries (e.g. Beniston 1997; Keiler et al. 2010), changes of
some climate factors were already observed in Slovenian Alps. The increase of
mean annual, minimal and maximal temperatures in the period from 1961 to 2011 is
statistically significant in all analysed meteorological stations in TNP
(547–2,514 m a.s.l.). Furthermore, the negative trends in the number of days with
snow cover during snow season were also noted (C ˇ repins ˇek et al. 2012). Considering
those environmental changes, we expect alterations in population and distribution of
rock ptarmigan, as well as changes of its habitat. In particular, due to its strong
dependence on weather conditions during the breeding season, the breeding phenology and breeding success are expected to be largely effected.
Following the effects of climate changes which have already been detected in some
alpine grassland vegetation (Cannone et al. 2007; Ko ¨rner 1999; Keller et al. 2000), we
predict accelerating plant succession by which the proportion of woody species will
increase. Additionally, the tree-line will shift upwards to higher altitudes. This process
is expected to proceed faster in dry habitats on carbonate ground, which is widespread
in the Slovenian Alps. Similar results are presumed in species distribution modelling
where due to increasing temperatures during the breeding season, potential habitats
are expected to decrease by up to two-thirds of area by the year 2070 (Revermann
et al. 2012). Such vegetation changes could reduce suitable habitats for rock ptarmigan
resulting in the greater isolation of already fragmented populations (Storch 2007) and
consequently lower gene flow exchange between them.
Additionally, the increase overlap between rock ptarmigan and other grassland
bird and/or small mammal species, causing greater competition between them, is
expected. So far, only few published data on interactions between rock ptarmigan
and other grassland species exist. The evidence about alpine marmot predation on
rock ptarmigan nests were reported from the Alps (Jordana et al. 2006 cited in
Figueroa et al. 2009), whereas the results from Pyrenees suggest that such interaction is only a sporadic event (Figueroa et al. 2009).
Finally, the loss of appropriate habitats with increasing human disturbances,
lower breeding success, as well as greater interspecific competition could affect the
viability of rock ptarmigan population in a level that cause the decline or extinction
of local populations.
190
T. Petras