How do cycle paths in peri-urban forests change the life and behavior of deer and pigs?

Watch out, boar, I’m going! Artwork frame.

Forests close to cities have an important recreational function. They are burdened with high attendance all year round, the movement of people even at night, and the competition of several recreational activities at once. Such use of the forests entails constraints for the management of the owners, can lead to damage to the vegetation and endanger the environment (waste, disturbance of animals, etc.). The impacts of tourism on animals differ significantly depending on the species, in particular according to their tolerance to disturbance, their ability to lead a hidden life, the possibility of transition to nocturnal activity, etc. The negative impacts of disturbance increase with the size of the animal species. . Conversely, some smaller species may benefit from changes caused by tourists and create adapted populations in cities. Animals can find plenty of food or refuge from predators and hunters in recreational forests. The peri-urban environment can thus become an important habitat where certain species reach high population densities and overpopulation. In central Europe, the large ungulates – deer, roe deer and wild boar – are among the species most sensitive to human disturbance.

One of the phenomena of tourism or cycling, which is currently experiencing an unprecedented boom in the Czech Republic, are cycle paths, which are natural or nature-friendly sports routes designed for mountain bikes, the width of which corresponds to the width of a bicycle. Bike paths allow you to combine active movement, adrenaline experience and stay in nature, that is, exactly what today’s society considers an ideal way to spend free time.

A problematic aspect of cycle paths is the preference of the route in a forest environment, avoiding overlaps with the existing road network, the search for places that are difficult to access, uneven terrain with obstacles and the desire of visitors to reach attractions. touristic, not overwhelmed by other tourists. In addition to officially functional areas, the forests of the Czech Republic are intertwined with miles of unofficial and illegally constructed trails.

Cycle paths already negatively affect the forest environment and its animal component indirectly (eg through disturbance) and directly (eg through the mortality of small animals). The direct effect on animals – their death on the bike path – affects mainly representatives of insects, reptiles, amphibians, but also small birds and mammals.

The indirect influence on the behavior of big game depends on the density of cycle paths in the forest, the frequency of cyclists, the density of game, the structure of forest stands, the presence of cycle bases, rest and other operating facilities near the Runway. Big game react differently to natural stimuli and to stimuli associated with the operation of a bike path or walking trails. It avoids the paths used by tourists and moves faster near them.

In the long term, the presence of intensively used cycle paths affects game distribution, activity and behaviours. A very clear consequence of the disturbance is a displacement of the activity of the individuals until the night. This change can increase the chances of survival of game species, but at the same time it affects the physiology of the species, their reproduction and their physical health through constant stress.

People’s recreational activities in peri-urban forests have an increasing impact on wildlife life. Researchers from Mendel University in Brno studied their interaction and published their findings in the article The Influence of Recreational Activities on the Distribution and Behavior of Roe Deer and Wild Boar in Suburban Forests, published in the journal Reports of Forest Research 4 /2021.

Interactions between tourist load and monitored game species were studied by scientists in a forest complex closely related to the city of Brno (with 400,000 inhabitants). The area of ​​interest extends on both banks of the Říčka stream, in the cadastral area of ​​the Brno-Líšeň district and the village of Mokrá-Horákov.

The zone has been defined to cover areas with different traffic intensities in the four sub-zones. The forest stands in the area of ​​interest were easily accessible to tourists via a network of paths and paths, which were used by hikers and partly by cyclists (hereafter paths) and also by a network of cycle paths intended only for cyclists (hereafter the trails).

Two sub-sectors (disturbed and trail-disturbed) were connected to the settlement and their average daily attendance during the summer season was min. 1000 hikers. The average trail density here was 83 and 179 m of trail per hectare of forest. The trail was in use in a busy area with a trail.

The second pair of areas (quiet and peaceful with a trail) was located about 2 km from Brno. These areas were much less used for short-term recreation (max. 400 pedestrians/day) and the network of paths was also less dense than in areas close to the city (13 and 51 m/ha respectively).

The results of the study did not provide clear evidence of the negative impact of human tourism activities on the abundance and behavior of deer and pigs in peri-urban forests. This suggests that wildlife may be affected by other factors that affect them more strongly than recreational use of the forest.

Deer numbers were paradoxically significantly higher in the disturbed area adjacent to the town than in the quieter, more remote area. Due to the truly extreme, year-round use of this area by tourists, scientists have assumed that deer will occur very little. However, its number was significantly higher than the average number in the common landscape in the vast majority of the territories of the Czech Republic and other European countries.

Cyclist on the trail from Prague to Letňany.  Illustrative photo.

Cyclist on the trail from Prague to Letňany. Illustrative photo.

Licence All rights reserved. Further distribution is only possible with the consent of the author

Source Prague City Hall

Disturbances affect wildlife life, but the presence of people in different environments and situations affects them differently. The impacts of human activities in the wild therefore depend significantly on the hiding possibilities of the game and also on how the game perceives the danger of people nearby.

If the global human load on the environment was high in the disturbed zone, on the other hand, two very favorable circumstances met. The first was a well-developed shrub soil. Roe deer have found rich food sources here and also plenty of shelter in hard-to-reach stands, where tourists don’t normally go. Although he was limited in his space activity, he was able to survive near busy trails.

Human presence thus appears to be a less important factor in the presence of game than the presence of dense undergrowth. The abundance of game may therefore be higher in disturbed areas with dense undergrowth than in calm areas without a shrub layer.

The second important factor is the reduction or even the exclusion of hunting activities in the disturbed area. In areas near the city, a large number of people moved during the day and there was no complete peace even at night. The environment is very confusing and the terrain is rugged and wildlife is virtually non-existent. Under these conditions, hunting is very difficult and also associated with a high risk of conflict with tourists, injury or death. Thus, the busy tourist area was very burdened with the presence of people, but at the same time hunting is practically impossible.

The local game population was obviously aware of the innocence of the tourists and was able to survive near busy trails. The effect of disturbance had no effect on the daily activity rate of deer.

Wild boar are also present in more disturbed environments than in less frequented environments. The area disturbed by the trail was the most attractive to the pig.

In the case of pigs, the researchers found exclusively nocturnal activity in both areas. The result shows that the degree of disturbance is so high from the pig’s point of view even in a quiet area that its behavior does not differ significantly from the behavior in the disturbed area.

An exclusively nocturnal lifestyle is not a natural behavior for a pig and is not physiologically optimal for this species. The boar has poor visual orientation at night. The unnatural nature of the nocturnal lifestyle shows the activity of pigs in an undisturbed environment, where much of their activity is concentrated in the light phase of the day. The strictly nocturnal activity of the pig is probably an adaptation to unfavorable conditions, close to human settlements represented by disturbing human activities.

The influence of recreational activities on the distribution and behavior of roe deer and wild boar in peri-urban forests is free to download.


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