Conservation values, ecosystem services and disservices
We observed increased diversity but decreased naturalness score in the crane-disturbed patches. This was due to the high cover of early-successional natural pioneer and disturbance-tolerant species and lower cover of generalists and competitors, especially Festuca pseudovina , the dominant grass species of alkaline grasslands. Patches of early-successional vegetation formed by grazing animals are integral parts of the studied ecosystem, so in the current extent, these early-successional patches do not pose a considerable conservation problem (Deák et al. 2015, Valkó et al. 2017).
We evaluated the effects of crane biopedturbation on the forage quality of grasslands using two proxies. Forage quality expressed by the Balázs-score was lower in the disturbed patches compared to intact grasslands, as crane ploughings are characterised by pioneer species that sprout and dry out early in the season, so they do not provide suitable forage in the summer and autumn (Balázs 1949). This implies that in large extent, crane biopedturbation can be problematic for grazing management. However, the negative consequences of decreased overall forage quality in the disturbed patches can be counterbalanced by the increased availability of forage plants in early spring. SLA is another proxy of forage quality, as livestock tends to select species with fresh, hydrated leaves characterised by large SLA (Balogh et al. 2021). We found that the disturbed patches were characterised by plants with larger SLA. This can be important for grazing management especially in the springtime, where the early-sprouting pioneer vegetation formed on the disturbed patches can provide important complementary forage for the livestock compared to the intact grasslands. The fresh sprouts of short-lived graminoids (such as Bromus hordeaceus , Hordeum hystrix and Poa bulbosa ) growing on crane-disturbed areas can provide good forage for livestock in early spring (Molnár 2017).
We found that crane-disturbed areas provided floral resources for a longer time and in larger quantity compared to intact grassland. This can support the maintenance of insect diversity, especially pollinator assemblages and palynivores (Bátori et al. 2020). This service has an especially high conservation importance in grass-dominated habitats such as the studied ecosystem with relatively few nectar-producing plants. Similar phenomenon was reported on the burrows of Siberian marmots (Marmota sibirica ), where the larger number of flowers and their higher visibility attracted more pollinators compared to undisturbed grasslands (Yoshihara et al. 2010).