Year-round evaluation of the conservation potential of seed-rich field margins under agri-environmental schemes for farmland birds, European hares, and common hamsters

Field margins on arable land, such as seed-rich strips (SRS), are an
important and widely implemented conservation measure under
agri-environment schemes. They are intended to contribute to the provision
of scarce food resources and shelter for various farmland species.
Although SRS are primarily designed to provide critical resources for
wildlife during the winter, they may also contribute to biodiversity
conservation throughout the year and across the full annual cycle of
farmland species. However, empirical evaluation of their conservation
potential over the annual cycle and across multiple taxa is missing.
Therefore, in this study, we conducted a year-round assessment of the
conservation potential of SRS for several avian (farmland birds and
seed-eating species in particular) and mammalian (European hares and
common hamsters) farmland species in arable-dominated agricultural
landscapes. Moreover, we investigated the role of the habitat
context (i.e., SRS placed along farmland hedges or inside crop fields) of
SRS on species abundance and diversity. Our results showed that during the
entire year, SRS significantly increased farmland bird abundance and
species diversity (including seed-eating species), as well as European
hare and common hamster abundance, compared to the controls (i.e.,
conventionally managed arable land). The SRS utilization varied
seasonally, with bird abundance in them being significantly higher from
late summer through winter, while European hare abundance increased
significantly only in the autumn and winter months. Notably, the most
substantial differences in farmland bird diversity between the SRS and
control areas were observed from August to November, whereas the greatest
disparities in bird abundance occurred during the winter months,
particularly from December to February. The habitat context of the plots
(both SRS and controls) generally did not affect the abundance or species
diversity of farmland birds. However, the abundance and species diversity
of seed-eating birds were higher in plots located along hedges. The
opposite pattern was found for the European hare. We conclude that
implementing SRS could significantly help in the conservation of avian and
mammalian species in arable farmlands. This is true not only in the autumn
and winter, when the dense and structurally complex vegetation in SRS
offers abundant nutrient-rich seeds and cover, but also in the summer,
when SRS provides invertebrates for a variety of farmland species.