Global Change Abstracts The Swiss Contribution - SCNAT

94
08.1-151
Integrating environmental and economic
performance to assess modern silvoarable
agroforestry in Europe
Palma J, Graves A R, Burgess P J, van der Werf W,
Herzog F
Switzerland, England, Netherlands
Agriculture, Soil Sciences , Ecology , Biodiversity ,
Economics
The environmental and economic performance
of silvoarable agroforestry in Europe is highly
variable. Multi-criteria analysis, using the PRO-
METHEE outranking approach, was used to evaluate
the integrated performance of silvoarable
agroforestry on hypothetical farms in nineteen
landscape test sites in Spain, France, and The
Netherlands. The silvoarable scenarios allocated a
proportion of the hypothetical farms (10 or 50%)
to silvoarable agroforestry at two different tree
densities (50 or 113 trees ha(-1)) on two different
qualities of land (best or worst quality land). The
status quo (conventional arable farming) was also
assessed for comparison. The criteria used in the
evaluation (soil erosion, nitrogen leaching, carbon
sequestration, landscape biodiversity, and
infinite net present value) were assessed at each
landscape test site; infinite net present value was
assessed under six levels of government support.
In France, the analysis showed, assuming equal
weighting between environmental and economic
performance, that silvoarable agroforestry was
preferable to conventional arable farming. The
best results were observed when agroforestry was
implemented on 50% of the highest quality land
on the farm; the effect of tree density (50113 trees
ha(-1)) was small. By contrast, in Spain and The
Netherlands, the consistently greater profitability
of conventional arable agriculture relative to
the agroforestry alternatives made overall performance
of agroforestry systems dependent on the
proportion of the farm planted, and the tree density
and land quality used.
Ecological Economics, 2007, V63, N4, SEP 15, pp
759-767.
08.1-152
The odd man out? Might climate explain the
lower tree alpha-diversity of African rain forests
relative to Amazonian rain forests?
Parmentier I, Malhi Y, Senterre B, Whittaker R J,
Alonso A, Balinga M P B, Bakayoko A, Bongers
F, Chatelain C, Comiskey J A, Cortay R, Kamdem
M N D, Doucet J L, Gautier L, Hawthorne W D,
Issembe Y A, Kouame F N, Kouka L A, Leal M E,
Lejoly J, Lewis S L, Nusbaumer L, Parren M P E, Peh
K S H, Phillips O L, Sheil D, Sonke B, Sosef M S M,
Global Change Abstracts – The Swiss Contribution | Terrestrial Ecosystems
Sunderland T C H, Stropp J, Ter Steege H, Swaine
M D, Tchouto M G P, van Gemerden Barend S, van
Valkenburg J L C H, Wöll H
Belgium, England, USA, Cameroon, Cote Ivoire,
Switzerland, Gabon, Ghana, Indonesia, Netherlands,
Scotland
Meteorology & Atmospheric Sciences , Forestry ,
Plant Sciences , Ecology , Biodiversity
1. Comparative analyses of diversity variation
among and between regions allow testing of alternative
explanatory models and ideas. Here, we
explore the relationships between the tree alphadiversity
of small rain forest plots in Africa and
in Amazonia and climatic variables, to test the
explanatory power of climate and the consistency
of relationships between the two continents. 2.
Our analysis included 1003 African plots and 512
Amazonian plots. All are located in old-growth primary
non-flooded forest under 900 m altitude. Tree
alpha-diversity is estimated using Fisher’s alpha calculated
for trees with diameter at breast height >=
10 cm. Mean diversity values are lower in Africa by a
factor of two. 3. Climate-diversity analyses are based
on data aggregated for grid cells of 2.5 x 2.5 km. The
highest Fisher’s alpha values are found in Amazonian
forests with no climatic analogue in our African
data set. When the analysis is restricted to pixels of
directly comparable climate, the mean diversity of
African forests is still much lower than that in Amazonia.
Only in regions of low mean annual rainfall
and temperature is mean diversity in African forests
comparable with, or superior to, the diversity in
Amazonia. 4. The climatic variables best correlated
with the tree alpha- diversity are largely different
in the African and Amazonian data, or correlate
with African and Amazonian diversity in opposite
directions. 5. These differences in the relationship
between local/landscape- scale alpha-diversity and
climate variables between the two continents point
to the possible significance of an array of factors
including: macro-scale climate differences between
the two regions, overall size of the respective species
pools, past climate variation, other forms of
long-term and short-term environmental variation,
and edaphics. We speculate that the lower alpha-diversity
of African lowland rain forests reported here
may be in part a function of the smaller regional
species pool of tree species adapted to warm, wet
conditions. 6. Our results point to the importance
of controlling for variation in plot size and for gross
differences in regional climates when undertaking
comparative analyses between regions of how local
diversity of forest varies in relation to other putative
controlling factors.
Journal of Ecology, 2007, V95, N5, SEP, pp
1058-1071.