The Structure and Dynamics of Agricultural Landscapes as Drivers of Biodiversity - Landscape Ecology for Sustainable Environment and Culture - page 292

landscapes where uncultivated elements are sparse. This has been underlined in
previous studies, which showed that landscape connectivity for forest species
increases when crops are grown high and dense (Fitzgibbon 1997 ; Ouin et al. 2000 ).
The relative contribution of semi-natural and cultivated elements for biodiversity is
however, likely to vary in time due to crop turnover and associated changing
suitability of the cropping systems mosaic (Holzschuh et al. 2011 ).

14.4.3 The Role of Farming Systems

We have shown that farming systems interact with biodiversity in several ways
and at different scales from fields to farm to groups of farms. This is summarized in
Table 14.4 . At the field scale, only species spending part of their life in crops are
concerned. Their populations are driven by the food and microclimatic resources
within the field. Processes in the mosaic of a few adjacent fields drive the same
type of species, the mosaics control movements from field to field, therefore the
possibilities to find food and shelter.
At a wider scale (about 100-1,000 ha), the controlling structure is the crop
mosaic and associated semi-natural elements. The different landscape patterns
offer different habitats and resources and, therefore, select the species that can
thrive. Both species living in semi-natural elements and cropland species are
concerned. When a landscape pattern changes by addition or removal of elements
or by a new spatial distribution, the species that are not adapted vanish while new
ones can come.

Table 14.4 Drivers of biodiversity at different spatial and time scales

Spatial unit Time unit Farming/crop processes Ecological processes

Field Week/month Crop growth/crop

management

Dynamics of populations
of short live field
species (1 month/
1-2 years)

Mosaic of some
adjacent fields

Month/year Heterogeneity of crop

management

Field species movement
from field to field

Crop mosaic
of &100-1,000 ha

1-10 years Crop sequences in the

different fields
Removal/
implementation of
semi-natural
elements

Differentiation of species
assemblages of both
fields and semi-natural
elements
Differentiation of species
assemblages and
population dynamics at
species level

Region 20-50 years Differentiation of

farming systems

Differentiation of species
assemblages according
to farming systems