Early spring fieldwork - Effects of soil perturbation by cranes on grassland vegetation

Common cranes (Grus grus) are large body-sized migratory birds. They breed in Northern Europe and during their migration, the open landscape of Hortobágy (East-Hungary) are a very important stopover site. In autumn, crane migration is a spectacular event (see a former post about it here). Thanks to the conservation efforts, the number of cranes visiting the Hortobágy National Park is increasing, and in the autumn of 2019 their estimated number was approximately 160,000. 

Related to the research plan of the Lendület Seed Ecology Research Group, and being part of the PhD project of Sándor Borza, we are interested in the effect of the large flocks of these migratory birds on the vegetation dynamics of alkaline grasslands. During foraging, cranes create distinct and unique vegetation patches by severe soil disturbance with their bill - this soil disturbance can be sometimes so severe that it resembles ploughing. That is why the Hungarian term for this spectacular phenomenon is 'crane-ploughing'. Our aim is to study the vegetation composition of the crane perturbations in comparison to undisturbed soil surfaces throughout the large pristine alkaline grasslands of the Hortobágy. 

We completed the early spring fieldwork a few days ago and below we share a few nice pictures about it.

Large grassland areas 'ploughed' by the cranes in Angyalháza. Photo by Sándor Borza.

One of our sampling plots in a crane-ploughing. Photo by Sándor Borza.

Vegetation sampling in the crane-ploughed area. Photo by Sándor Borza.

A less severely ploughed area. Photo by Laura Godó.

Erophila verna is an early spring annual species which is sometimes the dominant species of the crane perturbations. Photo by Laura Godó.

Crane feather on the crane-ploughing :) Photo by Laura Godó.

The perturbed surfaces are characterised by annuals and forbs and a lot of mosses. Photo by Balázs Deák.

One of our sample sites near Nagyiván. Photo by Balázs Deák.

The fine-scale microtopography typical to alkaline landscapes is well visible in springtime. Photo by Balázs Deák.