Global Change Abstracts The Swiss Contribution - SCNAT

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were counteracted by accelerated leaf senescence
in the highest O-3 treatment. The results suggest
that effects of elevated O-3 on the productivity
and floristic composition of subalpine grassland
may develop slowly, regardless of the sensitive response
to increasing N.
New Phytologist, 2007, V175, N3, pp 523-534.
08.1-87
Volcanic explosive eruptions of the Vesuvio
decrease tree-ring growth but not photosynthetic
rates in the surrounding forests
Battipaglia G, Cherubini P, Saurer M, Siegwolf R T
W, Strumia S, Cotrufo M F
Switzerland, Italy
Plant Sciences , Forestry , Meteorology & Atmospheric
Sciences
Volcanic eruptions impact the global and the
hemispheric climate, but it is still unknown how
and to what degree they force the climate system
and in particular the global carbon cycle. In this
paper, the relationships between individual eruptions
(reconstructed for the past using written records),
tree primary productivity (estimated using
ring widths), photosynthetic rate and stomatal
conductance (assessed by carbon and oxygen isotope
data) are investigated, to understand the impact
of volcanic eruptions on net primary production.
Data from a mixed stand of Fagus sylvatica
L. and Acer pseudoplatanus L. located in the area
of the Vesuvio volcanic complex (Southern Italy)
showed a significant decrease in ring width following
each eruption. Isotope analyses indicate a
change in climatic conditions after such events.
Specifically, the lower oxygen isotope ratio in the
tree-ring cellulose strongly suggests an increase in
relative humidity and a decrease in temperature,
with the latter resulting in a strong limitation
to tree-ring growth. The carbon isotope ratio was
only moderately but not significantly reduced in
the years of volcanic eruption, suggesting no major
changes in C fixation rates. This work is a case
study on the effects of volcanic eruptions resulting
in strong climatic changes on the local scale.
This is an opportunity to explore the process and
causal relationships between climatic changes
and the response of the vegetation. Thus, we propose
here a realistic model scenario, from which
we can extrapolate to global scales and improve
our interpretations of results of global studies.
Global Change Biology, 2007, V13, N6, JUN, pp
1122-1137.
Global Change Abstracts – The Swiss Contribution | Terrestrial Ecosystems
08.1-88
Intensified grazing affects endemic plant and
gastropod diversity in alpine grasslands of the
Southern Carpathian mountains (Romania)
Baur B, Cremene C, Groza C, Schileyko A A, Baur
A, Erhardt A
Switzerland, Romania, Russia
Plant Sciences , Biodiversity , Ecology , Zoology
Alpine grasslands in the Southern Carpathian
Mts, Romania, harbour an extraordinarily high
diversity of plants and invertebrates, including
Carpathic endemics. In the past decades, intensive
sheep grazing has caused a dramatic decrease
in biodiversity and even led to eroded soils at
many places in the Carpathians. Because of limited
food resources, sheep are increasingly forced
to graze on steep slopes, which were formerly not
grazed by livestock and are considered as local
biodiversity hotspots. We examined species richness,
abundance and number of endemic vascular
plants and terrestrial gastropods on steep slopes
that were either grazed by sheep or ungrazed by
livestock in two areas of the Southern Carpathians.
On calcareous soils in the Bucegi Mts, a total
of 177 vascular plant and 19 gastropod species
were recorded. Twelve plant species (6.8%) and
three gastropod species (15.8%) were endemic to
the Carpathians. Grazed sites had lower plant and
gastropod species richness than ungrazed sites.
Furthermore, grazed sites harboured fewer gastropod
species endemic to the Carpathians than
ungrazed sites. On acid soils in the Fagaras Mts, a
total of 96 vascular plant and nine gastropod species
were found. In this mountain area, however,
grazed and ungrazed sites did not differ in species
richness, abundance and number of endemic
plant and gastropod species. Our findings confirm
the high biodiversity of grasslands on steep slopes
in the Southern Carpathian Mts and caution
against increasing grazing pressure in these refuges
for relic plants and gastropods as well as for
other invertebrates.
Biologia, 2007, V62, N4, AUG, pp 438-445.
08.1-89
Effect of rock climbing on the calcicolous
lichen community of limestone cliffs in the
northern Swiss Jura Mountains
Baur B, Froeberg L, Müller S W
Switzerland, Sweden
Plant Sciences , Ecology
Exposed limestone cliffs in the Swiss Jura Mountains
harbour a diverse lichen community with
some rare species. Sport climbing has recently
increased in popularity on these cliffs. We examined
the effect of sport climbing on calcicolous