Global Change Abstracts The Swiss Contribution - SCNAT

Global Change Abstracts – The Swiss Contribution | Terrestrial Ecosystems 83
fect on most techniques. No technique can rescue
species that are difficult to predict. The predictive
power of species-distribution models can partly
be predicted from a series of species characteristics
and traits based on growth rate, elevational
distribution range, and maximum elevation.
Slow-growing species or species with narrow and
specialized niches tend to be better modeled. The
Swiss presence-only tree data produce models
that are reliable enough to be useful in planning
and management applications.
Ecological Monographs, 2007, V77, N4, NOV, pp
615-630.
08.1-125
Temporal changes in grazing intensity and
herbage quality within a Swiss fen meadow
Güsewell S, Pohl M, Gander A, Strehler C
Switzerland
Agriculture, Soil Sciences, Plant Sciences , Ecology ,
Biodiversity
Grazing is a possible tool for conservation management
in wetlands, but a frequent problem is
spatial variation in grazing intensity, which may
promote the degradation of the vegetation. Temporal
changes in grazing patterns may reduce
this problem by leading to a more homogeneous
overall use of the area. In a lakeshore wetland
(2.8 ha) grazed by Scottish Highland cattle from
May till September, we studied how the grazing
of nine vegetation types changes seasonally and
between years, and how this is related to the
quantity and quality of the herbage. We observed
cattle activity weekly throughout two grazing
periods, determined the biomass and nutrient
concentrations of the vegetation, analysed dung
samples, and carried out clipping experiments to
assess shoot regeneration after grazing. The annual
grazing intensity varied seven-fold among
vegetation types, and this pattern was closely
similar in both years. In several vegetation types,
however, grazing intensity changed seasonally.
Cattle first grazed tall grass-dominated vegetation
(Phragmition, Phalaridion), which had the
most digestible and nutrient-rich herbage, but
the poor regeneration of dominant species forced
the cattle to then graze small-sedge dominated,
nutrient-poor fen vegetation (Caricion davallianae).
These temporal changes in grazing patterns
slightly reduced the spatial variation in grazing
intensity. To take advantage of this effect,
relatively long grazing seasons are preferable to
shorter ones. Four years of grazing reduced the
above- ground biomass production and nutrient
concentrations of several vegetation types.
Therefore, years without grazing may be needed
to prevent a degradation of palatable plant communities
with low grazing tolerance.
Botanica Helvetica, 2007, V117, N1, JUN, pp
57-73.
08.1-126
Biodiversity and ecosystem functioning: reconciling
the results of experimental and observational
studies
Hector A, Joshi J, Scherer Lorenzen M, Schmid B,
Spehn E M, Wacker L, Weilenmann M, Bazeley
White E, Beierkuhnlein C, Caldeira M C, Dimitrakopoulos
P G, Finn J A, Huss Danell K, Jumpponen A,
Leadley P W, Loreau M, Mulder C P H, Nesshoever
C, Palmborg C, Read D J, Siamantziouras A S D,
Terry A C, Troumbis A Y
Switzerland, Germany, England, Portugal, Greece,
Ireland, Sweden, France, Canada
Biodiversity , Ecology , Plant Sciences
Functional Ecology, 2007, V21, N5, OCT, pp
998-1002.
08.1-127
The generality of habitat suitability models: A
practical test with two insect groups
Hein S, Binzenhöfer B, Poethke H J, Biedermann R,
Settele J, Schroeder B
Switzerland, Germany
Biodiversity , Ecology , Modelling , Zoology
For the design and declaration of conservation areas
as well as for planning habitat management
it is important to quantitatively know the habitat
preferences of the focal species. To take into account
the requirements of as many species as possible,
it would be of great advantage if one would
either (i) find one or several species whose habitat
requirements cover those of a large number of
other species or if one could (ii) identify a common
set of habitat parameters that is important
for the occurrence of many species. Ideally such
common habitat parameters should be easy to
measure. Only then they may be of practical value
in applied conservation biology. In this study, we
compared the habitat preferences of different insect
species (grasshoppers, bush crickets, butterflies,
moths) in the same region by applying identical
methods. To identify common explanatory
variables that predict the occurrence probability
of these species, we first tested the transferability
of the specific ‘species models’ to other species
within the same insect group. We tested how well
the incidence of one species can be predicted by
the occurrence probability of another species. The
‘best’ models within each group were then tested
for transferability between the different groups.
Additionally, we tested the predictive power of the