Letiště Letňany National Nature Monument

The Letňanské letiště – Letňany Airport NNM was declared in 2005 to protect the critically endangered animal species – the European souslik (Spermophilus citellus). The protected area covers an area of 468 953m² with a buffer zone of 163 377m². The protected area lies on the north-eastern outskirts of the city of Prague.
 
The European souslik is a rodent from the squirrel family (Sciuridae) which was originally bound to steppe biotopes. Sousliks arrived in this country at the time when agriculture began and used to be a common species in the lowlands, where they colonised grassy areas alongside tracks, field boundaries, meadows which were cut for hay, pasturelands, roadsides and growths of perennial fodder crops. In many areas sousliks were so abundant that they were regarded as vermin. Changes in the approach to agricultural use of the landscape and the introduction of new technology in the 1950s led to a rapid decline in souslik numbers, which is still continuing today.
 
The souslik needs short-stemmed grassland growths, either natural or artificially maintained, which allow these “ground squirrels” all-round views of the surroundings, so that the sousliks can see any approaching predators and also stay in visual contact with other members of the colony. According to mapping which was carried out in 2005, the European souslik still lives on its last 26 localities in the Czech Republic. Most of these colonies are bound to rather untraditional localities such as airfields, golf courses, recreational cottage areas and campsites where the “ground squirrels” can find permanently low grass growths which are regularly cut. However, the individual localities are isolated from each other and mostly have small numbers of sousliks, making them an highly vulnerable and endangered animal.
 
At present the most important locality for the European souslik in the Czech Republic is the airfield in Letňany, with a colony of 400-500 of these ground-dwelling rodents.
 
The European souslik’s lifestyle
Sousliks are active in the daytime and live together in colonies. Each animal lives in a burrow, which usually has several entrances and can be several metres long and up to one metre deep. The souslik renovates its burrow every year and increases the number of entrances. If danger is imminent these rodents hide in their burrows and they also spend the winter in hibernation underground.
 
Adult females go into hibernation as early as the middle of August, whereas adult males go into hibernation later. Young sousliks can be seen as late as the beginning of October if the weather is suitable. Unlike the hamsters, sousliks do not build up any food stocks underground and therefore they are entirely dependent on their body fat, which forms during the summer and can make up 1/3 of their body weight. Sousliks usually wake up from their hibernation during March.
 
The breeding season starts 2 or 3 weeks after the animals wake up. After a 24-day pregnancy females usually give birth to 5 blind and hairless young (the number of young can vary between 1 and 11). The young animals weigh around 50 grams but they can increase their weight by up to 5 times during the summer. Sousliks reach sexual maturity after their first hibernation.
 
These “ground-dwelling squirrels” eat the seeds, leaves, flowers and roots of grasses and herbs. They also like to hunt small insects such as locusts, grasshoppers, crickets and beetles. They will even eat voles and the eggs of ground-nesting birds.
 
Protection of the biotope for the European souslik also provides suitable conditions for other less well known but equally rare organisms. These include the small, oval-shaped black-brown coloured dung beetle Onthophagus vitulus, which can only develop in souslik droppings.
 
The declaration of the Letňanské letiště NNM does not prevent the current usage of the locality as an airfield. If the sousliks are to survive at this locality it will be necessary to continue with the present maintenance methods – regular and frequent cutting of the grass on the whole airfield – which suits the sousliks perfectly.
 
Visitors to the airfield are requested to respect the following rules to ensure the wellbeing of the European sousliks and their own safety:

  1. On the whole territory of the national nature monument and its buffer zone it is strictly forbidden to let dogs run free – as they dig up souslik burrows, which endangers the lives of the animals and also the safety of the aircraft.
  2. Movement of people who are not members of the airport personnel is only allowed outside of the areas which are marked with red and white markers of the borders of aircraft taxiing areas.
  3. Aircraft propellers and winch cables can cause fatal injuries – therefore it is forbidden to approach aircraft and winches without an accompanying member of the airport staff.
  4. For safety reasons it is not permitted to cross the take off and landing strips and the area under where aircraft descend to land.