Global Change Abstracts The Swiss Contribution - SCNAT

Global Change Abstracts – The Swiss Contribution | Terrestrial Ecosystems 103
in this fern species, and as a consequence, phenotypic
plasticity is assumed to be favored. This
contrasts with results found in similar studies
of herbaceous flowering plants where genetic
adaptation to gradients like altitude is common.
However, when data from the more distant Italian
and Spanish populations of A. filix- femina were
included, significant variation was detected.
American Journal of Botany, 2007, V94, N6, JUN,
pp 965-971.
08.1-171
Examining native and exotic species diversity
in European riparian forests
Schnitzler A, Hale B W, Alsum E M
Switzerland, France, USA
Plant Sciences , Ecology , Biodiversity , Forestry
This study performs a meta-analysis of existing
studies of European riparian forests to investigate
which exotic species have successfully established
in intact riparian forests and which characteristics
of these forests correspond with successful establishment.
We used analysis of covariance models
to investigate the relationship between community
species richness, percent exotic species, and
several environmental variables. We found a total
richness of 1380 species, of which 45 (3.3%) were
exotic. Species- rich communities generally had
the higher percentage of exotics, but were not
significantly related to latitude or environmental
variables. Exotics, in contrast, were at generally
higher levels at lower latitudes and were more
abundant in large river plains and communities
with intermediate levels of disturbance. These
results suggest that future climate change and
human actions that mimic intermediate levels of
disturbance may further enhance the spread of
exotic species.
Biological Conservation, 2007, V138, N1-2, AUG,
pp 146-156.
08.1-172
Speciation reversal and biodiversity dynamics
with hybridization in changing environments
Seehausen O, Takimoto G, Roy D, Jokela J
Switzerland, USA
Biodiversity , Ecology
A considerable fraction of the world’s biodiversity
is of recent evolutionary origin and has evolved
as a by-product of, and is maintained by, divergent
adaptation in heterogeneous environments.
Conservationists have paid attention to genetic
homogenization caused by human-induced translocations
(e.g. biological invasions and stocking),
and to the importance of environmental heterogeneity
for the ecological coexistence of species.
However, far less attention has been paid to the
consequences of loss of environmental heterogeneity
to the genetic coexistence of sympatric species.
Our review of empirical observations and our
theoretical considerations on the causes and consequences
of interspecific hybridization suggest
that a loss of environmental heterogeneity causes
a loss of biodiversity through increased genetic
admixture, effectively reversing speciation. Loss
of heterogeneity relaxes divergent selection and
removes ecological barriers to gene flow between
divergently adapted species, promoting interspecific
introgressive hybridization. Since heterogeneity
of natural environments is rapidly deteriorating
in most biomes, the evolutionary ecology
of speciation reversal ought to be fully integrated
into conservation biology.
Molecular Ecology, 2008, V17, N1, JAN, pp 30-44.
08.1-173
Altitudinal and horizontal shifts of the upper
boundaries of open and closed forests in the
Polar Urals in the 20th century
Shiyatov S G, Terentev M M, Fomin V V, Zimmermann
N E
Russia, Switzerland
Meteorology & Atmospheric Sciences , Forestry ,
Plant Sciences , Ecology
In the Polar Urals (the Rai-Iz massif and Mounts
Tchernaya and Malaya Tchernaya), altitudinal and
horizontal shifts of the upper boundary of open
and closed larch forests in the 20th century have
been studied. Spatiotemporal parameters of these
shifts have been assessed with the aid of the ARC/
INFO geographic information system (ESRI Inc.,
United States), using our original large-scale geobotanical
maps showing the distribution of different
types of forest-tundra communities in the
early 1910s and 2000s. The results show that tree
vegetation has been actively expanding to higher
elevations over the past 90 years. On average, the
upper boundaries of open and closed forests have
ascended 26 and 35 m and shifted horizontally
290 and 520 m, respectively. These shifts have been
conditioned by climate warming and increasing
humidity observed since the 1920s.
Russian Journal of Ecology, 2007, V38, N4, JUL, pp
223-227.
08.1-174
Temperate grasslands and global atmospheric
change: a review
Soussana J F, Lüscher A
France, Switzerland
Meteorology & Atmospheric Sciences , Plant Sciences
, Ecology , Agriculture, Soil Sciences