Résumé
1. The composition of agro-ecological landscapes is thought to have
important implications for the production of major crops through its
effects on pollinator abundance and behaviour. 2. We explored the roles of
land cover and land cover heterogeneity on bee nest distribution for Apis
dorsata, a key species for coffee pollination, in a complex agroforest
landscape. We emphasized scaling and non-uniform effects by combining two
different approaches of spatial analysis, the point-pattern analysis and
surface-pattern analysis. 3. We found non-exclusive, positive effects of
agroforests, forest fragments and land cover heterogeneity on the presence
and number of nests. The distribution of nests responded to habitat
heterogeneity at small scale (<100m), forest fragments at medium
scale (<300 m) and to agroforest at larger scales (500 m to 2 km).
Our multi approach highlights that the landscape effects were neither
linear nor uniform within the study zone. Nests were consistently located
in areas of medium agroforest density or medium to high forest density,
but were absent where forest fragments are the most concentrated. 4. The
agroforest matrix was particularly important in shaping the size of nest
aggregates. Nests tended to be few when there is low tree cover at broad
scale, while nests were numerous when agroforest patches are abundant
within the bees’ foraging range. 5. Synthesis and applications. Our study
revealed that structurally complex landscapes appear to support bee
populations. The spatial arrangement of different land covers affected
honeybee nest distributions by providing nesting and foraging resources
across multiple scales. The results suggest that continued intensification
of small forest fragments and expansion of large monospecies plantations
will be deleterious to Apis dorsata populations. Fragmentation of the
agroforestry matrix at small scales (100s meters) does not, however,
appear detrimental for Apis dorsata as long as sufficient diversified
resources are available at the landscape scale (kms).22-Sep-2017