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15% of interfaces between
complementary crops
84% of interfaces between
complementary crops
Land uses:
Abundance of carabid beetles :
0-10
6
individuals
Maize
Wheat
Barley
10
6
-10
9
individuals
10
9
-10
12
individuals
Fig. 14.7 Spatial distribution of carabid populations in the crop mosaic after 30 years of
simulation (10 cycles of rotation) for the two scenarios of crop spatial organization (15 and 84 %
of interfaces between complementary crops: maize-wheat, wheat-barley and maize-barley)
(Vasseur
2012
)
(maize-wheat, maize-barley, barley-wheat), is promoted (Fig.
14.6
b). Adjacency
between complementary crops each year increases survival of carabid beetles until
the end of the reproductive period, ensuring a more important renewal of carabid
populations. It also allows, in the latter part of carabid activity period, a rapid
colonization of new, suitable patches (maize crops). Thus, the spatio-temporal
heterogeneity of the cropping systems mosaic is likely to increase landscape
spatio-temporal connectivity for this carabid species. Over the long term, this
process could result in a homogenization of populations' spatial distribution, and
enhance their resilience to frequent local extinctions (Fig.
14.7
).
14.4 Discussion
14.4.1 Semi Natural Elements
Our results confirm that semi-natural or more natural elements (Fahrig et al.
2011
)
have an impact on biodiversity for all considered taxa. This has been shown by
previous results on the effect of the amount of these elements, considered as a
measure of landscape complexity, on several taxonomic groups. Most of the
studies show a positive effect of semi natural elements, and conclude that complex
agricultural landscapes favor biodiversity as measured by the number of species
(Tscharntke et al.
2005a
,
b
). The use of several taxa permits to discuss this
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