mountain systems call for a recent gene flow in North-South direction (Theissinger
et al. 2012).
Although some similarities exist between the alpine faunas and floras of the
Apennines and the Balkan high mountain systems (e.g. shared endemic plants such
as Aurinia rupestris, Leontopodium nivale, Saxifraga glabella), the exchange
between these two mountain areas might in most cases not be very recent, as in
most of the examples referred to above (cf. Schönswetter and Schneeweiss 2009;
Louy et al. 2013).
3.4 Arctic–Alpine Disjunction
In arctic–alpine species, i.e. species with occurrences in the high mountain ranges in
the South and in the Arctic, wide zonal ice age distributions in the periglacial steppe
region with postglacial retreats uphill and polewards have classically been assumed
(Holdhaus 1954). Following this assumption, the disjunction between northern and
southern populations dates only to the postglacial and should not have resulted in
corresponding differentiations, so that mostly similar populations should be found
in the North and the South. In support of this theory, highly similar genetic make-up
of northern and southern populations has frequently been recorded (e.g.
Schönswetter et al. 2003c, 2008; Albach et al. 2006; Muster and Berendonk 2006;
Skrede et al. 2006; Ehrich et al. 2007; Reisch 2008; Schmitt et al. 2010).
In many arctic–alpine species, only part of the southern mountain populations is
similar to the ones from the Arctic, while others are not. These patterns call for
additional perialpine glacial refugia in close proximity to the mountain ranges (as
exclusively in the alpine disjunct species) supplementing the extended zonal distributions. In most of these cases, the Alps and the Arctic share identical genetic
lineages, which were thus apparently derived from this periglacial steppe region.
Many species occurring in the Pyrenees and the Tatras also share these lineages
(e.g. Muster and Berendonk 2006; Schmitt et al. 2010). However, lineages in the
Alps do not always have a northern origin. For example, populations of Gentiana
nivalis derived from the extended zonal ice age distribution were detected in the
North, the Pyrenees and Carpathians, while three other lineages exist in the Alps,
calling for three perialpine glacial refugia in addition to the zonal range (Alvarez
et al. 2012). In the stonefly Arcynopteryx dichroa, the northern clade is limited in
the South to the Black Forest, thus supporting the existence of an extended zonal
range of the species, but its limited impact on the postglacial recolonisation of the
southern mountains indicates that these were mostly colonised from glacial refugia
in their foothills (Theissinger et al. 2012).
Acknowledgements I thank Andrew Liston (SDEI, Müncheberg) for linguistic improvements.
Constructive comments of two anonymous referees are acknowledged.
70
T. Schmitt
et al. 2012).
Although some similarities exist between the alpine faunas and floras of the
Apennines and the Balkan high mountain systems (e.g. shared endemic plants such
as Aurinia rupestris, Leontopodium nivale, Saxifraga glabella), the exchange
between these two mountain areas might in most cases not be very recent, as in
most of the examples referred to above (cf. Schönswetter and Schneeweiss 2009;
Louy et al. 2013).
3.4 Arctic–Alpine Disjunction
In arctic–alpine species, i.e. species with occurrences in the high mountain ranges in
the South and in the Arctic, wide zonal ice age distributions in the periglacial steppe
region with postglacial retreats uphill and polewards have classically been assumed
(Holdhaus 1954). Following this assumption, the disjunction between northern and
southern populations dates only to the postglacial and should not have resulted in
corresponding differentiations, so that mostly similar populations should be found
in the North and the South. In support of this theory, highly similar genetic make-up
of northern and southern populations has frequently been recorded (e.g.
Schönswetter et al. 2003c, 2008; Albach et al. 2006; Muster and Berendonk 2006;
Skrede et al. 2006; Ehrich et al. 2007; Reisch 2008; Schmitt et al. 2010).
In many arctic–alpine species, only part of the southern mountain populations is
similar to the ones from the Arctic, while others are not. These patterns call for
additional perialpine glacial refugia in close proximity to the mountain ranges (as
exclusively in the alpine disjunct species) supplementing the extended zonal distributions. In most of these cases, the Alps and the Arctic share identical genetic
lineages, which were thus apparently derived from this periglacial steppe region.
Many species occurring in the Pyrenees and the Tatras also share these lineages
(e.g. Muster and Berendonk 2006; Schmitt et al. 2010). However, lineages in the
Alps do not always have a northern origin. For example, populations of Gentiana
nivalis derived from the extended zonal ice age distribution were detected in the
North, the Pyrenees and Carpathians, while three other lineages exist in the Alps,
calling for three perialpine glacial refugia in addition to the zonal range (Alvarez
et al. 2012). In the stonefly Arcynopteryx dichroa, the northern clade is limited in
the South to the Black Forest, thus supporting the existence of an extended zonal
range of the species, but its limited impact on the postglacial recolonisation of the
southern mountains indicates that these were mostly colonised from glacial refugia
in their foothills (Theissinger et al. 2012).
Acknowledgements I thank Andrew Liston (SDEI, Müncheberg) for linguistic improvements.
Constructive comments of two anonymous referees are acknowledged.
70
T. Schmitt