Peculiarity of usage of openings by lynxes

This post adverts the recent shift in the habitat-related lynx distribution for usage of openings and the lynx reaction to get back to forest in connection with the considerable changes in the wolf number in Naliboki Forest.

In the book “Unknown Eurasian lynx Lynx lynx: New findings on the species ecology and behaviour” by Vadim Sidorovich, Jan Gouwy and Irina Rotenko (2019) we have stated that the pattern of habitat usage by lynxes is characterized by the absolute preference for forested biotopes. It is mainly formed by the on-going interference with wolves, because a lynx that is in an opening, without the possibility to climb trees to escape an attack, may be killed by wolves. Indeed, in an opening a lynx, which is overtaken by wolves (a wolf is a better runner for a fairly long distance), has a little chance to survive. Lynxes know this and avoid large openings in forested terrains, where wolves are common.

The first time this hypothesis appeared during stay in Hiiumaa island in Estonia in the late 1990s, when the lynx was common and the wolf was rare there. At that time, in Hiiumaa, two-thirds of the lynx tracks found were situated in openings among the forest. Those openings originated from the former marshlands, and the open structure included roads and drainage canals with willow bushes and a few birtch trees nearby. Lynxes mostly walked at the opening edges there, at the border of the forest.  But there were many lynx tracks crossing the openings as well. At that time in Hiiumaa we registered numerous lynx hunt-watching and resting sites in the middle of an opening somewhere at a drainage canal near a willow bush or more frequently on hay piles. All categories of lynxes, not only adult males, but also mothers with kittens and subadults visited these openings in Hiiumaa rather often.

Before the winter 2018-2019 in Naliboki Forest, which has a very similar structure in its terrains,  we registered such lynx behaviour very rarely compared to Hiiumaa’s terrain, only a few times per year. In those rare cases, only adult males took the liberty to walk in an opening, but never far away from the forested edges (not further than 50 meters). Only once during more than 30 years in Naliboki Forest, we registered a crossing of a fairly wide opening (about 400 meters) by an adult male lynx.

Another example confirming our hypothesis, was found in the Krasny Bor terrain of Paazierre Forest. In the 1980s, lynxes and wolves were both common there, and lynxes were only very rare visitors of the open habitats. Quite opposite, in the period from the late 1990s to 2016, the heavy eradication of wolves was on-going year-round, so wolves became rare in Krasny Bor. Following this, in effect, lynxes began visiting vast sparsely forested terrains at the west side of Krasny Bor rather often; in that area the lynx tracks became commoner than in the densely forested localities of the terrain.

During the last several years in Naliboki Forest in the dramatic effect of  direct and indirect  impacts of lynxes on the wolf reproduction (killing of pups and heavily pregnant female wolves, wolf breeders emigration for denning) the number of wolves in the terrain in the period from May to February declined markedly. From the beginning of November 2018 till the late January 2019 resulting of the above lynx impact and higher pressure on wolves by hunters there were 15 to 20 wolves only in the area about 2700 km2 in Naliboki Forest and its rural-forest surroundings (see the wolf distribution map for the early January 2019). This period in many localities wolf presence was not registered at all.  As to the number of lynxes it was higher than 100, and lynxes were easily registered in all the localities.

Having this interesting situation, we (Vadim Sidorovich, Jan Gouwy, Sanne Van Den Berge, Maximilian Hetzer, Siege Van Ballaert and Reinhardt Strubbe) tried to investigate the possible changes in the lynx distribution by camera-trapping (about 70 of them were applied) and by snowtracking. Indeed, besides of camera-trap registrations of lynxes within openings, we have found a number of stay of lynxes in the large open habitats that are common in Naliboki Forest.  Lynx track registrations and snowtracking revealed 17 fairly long presence of lynxes within large openings for the tracking distance of 1.4 up to about 10 km. In the three registered cases that was mothers with 2 and 3 kittens.  Lynx walking mostly in openings for 3-5 km was quite typical in that situation in Naliboki Forest. They seemingly tried to hunt and mark a lot by urine in the openings.  Mostly those are former large swamps that were drained in the Soviet time and them abandoned by human. Nowadays, such mostly open habitats consist of abandoned peatery, a lot of meadows with willow bushes, drainage canals with some silver birches and black alders as well as some agriculture. Open grassy marshes and inundated areas are typical for the abandoned peateries.

By the mid-February 2019 in Naliboki Forest a lot of stranger wolves have arrived to take part in the mating. The number of wolves in this terrain got 40 to 60 and their presence appeared to be frequent in all the localities. In this returned situation, when wolves got common again,  lynxes have switched their stay for forest habitats again, and this switch in habitat usage has happened surprisingly fast.

Thus, the above-described pattern in the lynx behaviour suggests one more time a great importance of lynx-wolf interference for the lynx distribution and habitat usage. Also, that demonstrates a high adaptability of the lynx, because the species able to trace effectively the situation in progress and change its behaviour  beneficially.

 

 

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