Agricultural management in our landscape comprehensively affects the animals living in it. Intensive cultivation of large areas results in the loss of large numbers of animals and a significant reduction in species diversity. Intensive agricultural farming began to have the greatest effect on the decline in species diversity in the 1970s and continues to this day. The decline also concerns the number of hares, which depend on a well-functioning agricultural landscape. Therefore, the main cause of the decline in the hare population is the altered landscape, where there is a lack of sufficient natural shelter for small game, as well as the intensive use of chemicals in agriculture. Our current unhappy situation is not indifferent to our game managers and they are trying to reverse it.
One of the ways to help the growth of the hare population in our landscape is the method of releasing hares bred in special pens into the wild. Unfortunately, the mere release of hares into the wild without knowledge of the relevant facts and without the application of additional measures often leads to failure. Therefore, a team of scientists from the Research Institute of Forestry and Game Management and the Faculty of Forestry and Wood Sciences, led by Ing. Jan Cukor, which precisely defined the limiting factors influencing the success in the release of the hare, tried to help to game managers in their effort.
The research itself took place in the České Meziříčí hunting ground and during it 22 hares from intensive breeding were marked. Each individual was given a collar with an antenna so that his movement and eventual death could be monitored. The evaluation of the data yielded a lot of interesting information.
The results showed that only 4 of the 22 released hares survived in the wild. Thanks to the collar with the antenna, it was possible to find the dead individuals and use an autopsy to find out the cause of their death. In 7 cases, the death of the hare was due to fox predation, in 5 cases unspecified health problems, in 3 cases a collision with vehicles, in 2 cases it was not possible to indicate the cause and in 1 case the transmitter was lost.
A remarkable finding was that 5 cases of fox predation occurred within the first 12 days and within 5 days all 5 cases of death caused by poor health of the organism occurred. This shows that if the hare got used to the environment, survived at least 12 days and learned to hide from predators, it greatly increased its chances of survival. The time of discharge also had a great influence on mortality. Hares released in July and August survived an average of 125 and 92 days, while individuals released in February, April and October survived an average of 26, 40 and 6 days, respectively. 5 tested hares were released without the possibility of acclimatization in the fence and all died within 10 days.
The data from the collars made it possible to define the home range of the hare released from intensive breeding, which was compared with the home district of the hare living in the wild. While the released individuals inhabited a home district of just over 23 hectares, the wild individuals used an area of over 43 hectares.
The results of the research provided essential information that can be used to release hares into the wild, and thus provide them with a much higher chance of survival. The basic measures appear to be the release of hares first into the acclimatization fence, the selection of a suitable period and intensive hunting of predators in the vicinity of the release. Let's hope that the game managers will use the conclusions of this work in practice and help the hare to start increasing its numbers. At the same time, however, there should be fundamental changes in agriculture, without which we can hardly ensure the successful return of small game to the landscape.
Cukor J, Havránek F, Linda R, Bukovjan K, Painter MS, et al. (2018) First findings of brown hare (Lepus europaeus) reintroduction in relation to seasonal impact. PLOS ONE 13 (10): e0205078.
Ing. Jan Cukor
He is a doctoral student at the Department of Silviculture. In addition to supporting biodiversity, the stability of forest ecosystems and other forestry activities, he also deals with the topic of the return of hares to our landscape.
Prepared by: Daniel Švrčula