Global Change Abstracts The Swiss Contribution - SCNAT

Global Change Abstracts – The Swiss Contribution | Terrestrial Ecosystems 73
community composition is likely to be successful
if site conditions (hydrology, nutrient status) remain
intact and if common habitat specialists are
still present in the vegetation and/or seed bank.
Botanica Helvetica, 2007, V117, N1, JUN, pp 1-13.
08.1-95
Dynamics in debris-flow activity on a forested
cone - A case study using different dendroecological
approaches
Bollschweiler M, Stoffel M, Schneuwly D M
Switzerland
Forestry , Plant Sciences , Geomorphology
Dendrogeomorpho logical analyses of trees affected
by debris flows have regularly been used to
date past events. However, this method has always
been limited to forested cones where trees registered
the impact of previous events. The minimum
age dating of trees growing in the debris
deposits can, in contrast, provide information on
the latest possible moment of past activity. In this
paper, we report on results obtained from a combination
of these two approaches on a forested
cone in the Valais Alps (Switzerland). A detailed
geomorphic map in a scale of 1: 1000 served as a
basis for the sampling strategy. Disturbed Larix
decidua Mill. and Picea abies (L.) Karst. trees growing
in the deposits allowed reconstruction of 49
events between AD 1782 and 2005 as well as the
determination of the spatial extent of events. In
the debris-flow channels where survivor trees are
missing, we selected the oldest post-event trees
and assessed their age by counting their growth
rings. Missing rings due to lack of center as well
as to sampling height were added so as to determine
real tree age. The combination of the dendrogeomorphological
event reconstruction with
the assessment of germination dates of successor
trees allowed realistic approximation of the
minimum time elapsed since the last debris-flow
activity in 23 of the 29 channels present on the
current-day cone surface. In general, channels in
the northern part of the cone and those close to
the currently active channel generally show signs
of (sub-) recent activity with one last overbank sedimentation
event in the 1980s, whereas signs of
debris-flow activity are absent from the channels
in the outermost part since the late 19th century.
As a consequence of the deeply incised channel
and the stabilization measures undertaken along
the banks, signs of debris flows are missing in the
tree-ring record for the past two decades.
Catena, 2008, V72, N1, JAN 1, pp 67-78.
08.1-96
Methanol exchange between grassland and
the atmosphere
Brunner A, Ammann C, Neftel A, Spirig C
Switzerland
Agriculture, Soil Sciences , Plant Sciences , Meteorology
& Atmospheric Sciences , Ecology
Concentrations and fluxes of methanol were measured
above two differently managed grassland
fields (intensive and extensive) in central Switzerland
during summer 2004. The measurements
were performed with a proton-transfer-reaction
mass-spectrometer and fluxes were determined by
the eddy covariance method. The observed methanol
emission showed a distinct diurnal cycle and
was strongly correlated with global radiation and
water vapour flux. Mean and maximum daily
emissions were found to depend on grassland species
composition and, for the intensive field, also
on the growing state. The extensive field with a
more complex species composition had higher
emissions than the graminoid-dominated intensive
field, both on an area and on a biomass basis.
A simple parameterisation depending on the water
vapour flux and the leaf area index allowed a
satisfying simulation of the temporal variation of
methanol emissions over the growing phase. Accumulated
carbon losses due to methanol emissions
accounted for 0.024 and 0.048% of net primary
productivity for the intensive and extensive field,
respectively. The integral methanol emissions over
the growing periods were more than one order of
magnitude higher than the emissions related to
cut and drying events.
Biogeosciences, 2007, V4, N3, pp 395-410.
08.1-97
A standardized procedure for surveillance and
monitoring European habitats and provision
of spatial data
Bunce R G H, Metzger M J, Jongman R H G, Brandt
J, de Blust G, Elena Rossello R, Groom G B, Halada
L, Hofer G, Howard D C, Kovar P, Mucher C A,
Padoa Schioppa E, Paelinx D, Palo A, Perez Soba M,
Ramos I L, Roche P, Skanes H, Wrbka T
Netherlands, Denmark, Belgium, Spain, Slovakia,
Switzerland, England, Czech Republic, Italy, Estonia,
Portugal
Ecology , Biodiversity
Both science and policy require a practical, transmissible,
and reproducible procedure for surveillance
and monitoring of European habitats, which
can produce statistics integrated at the landscape
level. Over the last 30 years, landscape ecology has
developed rapidly, and many studies now require
spatial data on habitats. Without rigorous rules,