Eurasian crane (Grus grus) as ecosystem engineer in grasslands ‒
conservation values, ecosystem services and disservices related to a
large iconic bird species
Abstract
Large bird species, such as cranes are involved in human-wildlife
conflicts as they often forage in croplands. The Eurasian crane (Grus
grus) is a large iconic bird species, protected across Europe, which,
thanks to conservation programs and its ability to utilize croplands for
foraging, shows a strongly increasing population trend. This exaggerates
the already existing conflicts between crop farmers and cranes spilling
over to natural habitats, where foraging by large flocks can lead to
land degradation. To date, no studies have evaluated the effects of
biopedturbation by cranes in grasslands, despite these habitats provide
important feeding grounds for this large bird across its whole range.
Here we evaluated the effect of biopedturbation by foraging Eurasian
cranes on the vegetation of dry grasslands in Hungary. We used
indicators of vegetation naturalness, forage quality and floral resource
provision to evaluate the ecosystem state from multiple aspects. We
sampled 100 quadrats in disturbed patches and 100 in intact grasslands
in two seasons and two years (800 observations). We found that cranes
created distinct habitat patches with different species composition
compared to undisturbed areas. These early-successional patches that
increased the plant diversity and floral resources but decreased the
area of intact grasslands. Although crane-disturbed patches could
provide forage for livestock early in the season, the forage quality of
the vegetation became poor later in the year. Given the strong increase
of the global crane population, monitoring the landscape-level extent of
the disturbed areas, and developing a complex prevention and mitigation
strategy would be important.