Before, in 1950s-1970s the mountain hare was common species in Naliboki Forest. According to the local hunter’s words in those winters the species tracks covered snow cover densely and more or less evenly in each fragment of this forested terrain. In the late 1990s and beginning of 2000s it looked like the mountain hare local population density in Naliboki Forest was evidently in a decline; there were censused only 0.2-0.8 inds per one square km. In 2005-2010 the evident growth of the local population of mountain hare was registered, and more or less high number of the species continued till 2014 (2.9-6.1 inds per one square km). Then during the each next winter we faced with fewer and fewer number of mountain hares in Naliboki Forest.Continue reading “Declines in mountain hares in Naliboki Forest, central west of Belarus: hypotheses and arguments”
Below we consider the combined impact of lynxes and wolves on the populations of red foxes and raccoon dogs, because their predation effects on the populations of these victim species are hard to separate. First, we list the gained data on the killing rate of red foxes and raccoon dogs by lynxes and wolves from two main different methods i.e. telemetry and snowtracking.Continue reading “Extermination of red foxes and raccoon dogs by lynxes and wolves in forested terrains, and the peculiarities of local populations of these medium-sized carnivores”
Historically, the badger was fairly common species in Naliboki Forest that is in the north-western part of Belarus. Besides the respective information that was obtained from the locals (e.g. Baliaslaw Sadowski, Lianard Jurevich, Edzik Khmara), who lived and was familiar with the forest in the 1930s-1960s, also presence of numerous former badger setts suggests about the commonness of badgers. Approximatelly, the density of main setts, where badger families lived before, was not lower than 15 per 100 km2 in the most ecologically rich southern part of Naliboki Forest and about 4 per 100 km2 in the central and central-northern parts of the terrain, where habitat carrying capacity for badgers is markedly lower. It means that the former density in more or less undisturbed badger population in Naliboki Forest ranged approximately between 20 and 120 individuals per 100 km2 in relation to the habitat carrying capacity of the terrain.Continue reading “Recovering of the badger local population in Naliboki Forest, NW Belarus in connection with winter warming and predation of lynxes and wolves”
While observing and censusing raptors in Naliboki Forest, it was an outstandingly high species diversity of diurnal raptors and owls. Here is a possible explanation of this phenomenon.Continue reading “Outstandingly high species diversity of raptors (diurnal raptors and owls) in Naliboki Forest”
Till the 1960s Naliboki Forest, which is situated in the north-western Belarus, was a greatly swamped terrain, where on the area about two thousands km2 swamps of various types and sizes were interspersed with dry land forests the terrain-wide. Open grassy marshes constituted about 19% of the terrain. Approximately a third part of the forest habitats that covered about 76% of the area were swamped too (Sidorovich, 2016). Such a swamped forest was either in kinds of black alder and downy birch mixture (with prevalence of one of the species) or that was raised bogs with suppressed or normal pines. Continue reading “Dramatic situation in the beaver population in Naliboki Forest in relation to hotter and drier summers nowadays”
Every time rereading the excellent wolf monograph by Mech and Boitani (2003), in particular, the item about wolf communication by Harrington and Asa, I was surprised to find out how rich voice-communication of wolves in North America and somewhere else can be. In my study areas in Belarus (look like in the whole country) I can characterize wolves as non-howling let’s say silent. More and more I become convinced that wolves in Belarus avoid to produce any loud noise.
Population decline of carnivore species may happen suddenly, develop rather fast and proceed short-term. For instance, such demise character was known for the European mink in Belarus and Russia (Macdonald et al., 2002; Sidorovich, 2011). Population decline of other carnivore species may pass gradually and less evident, and a considerable decrease in population density may take many more years.
The situation that is characterized by gradual and long-term decline is fairly hard to notice, while manipulating short-term data only. It takes much time to establish a right hypothesis on the decline and to prove the hypothesis. Usually, in such a case, when a population decline appeared to be evident, it is already too late to get a complete dataset to analyze the declining process and to reveal the factors that impacted the population. The polecat Mustela putorius population decline in Belarus was characterized by the mentioned features of gradual and long-term decline (see Sidorovich, 2011). Our results of the study on the polecat demise suggest the following negative factors that are responsible for the population decline.
A year ago, while publishing the book about badgers and raccoon dogs in Belarus (“Badger and Raccoon dog in Belarus: Population studies with implication for the decline in badgers“, Minsk, 2017), it looked like we knew all possible ways of interference between raccoon dogs and badgers. We registered blocking badgers sleeping in the sett’s hibernating chamber by raccoon dogs with suffocating of the badgers afterwards; killing of badger cubs by raccoon dogs; non-effective attacks of badger on raccoon dog at its sett as well as a lot of marking of badger setts by both species in order to prevent usage of the sett by the burrow-competitor species. Any attack of an active badger by raccoon dogs was not registered, and that was considered as something non-real.
In one of our study area on the question, which is the Lovat terrain in Paazierre Forestin northern Belarus, both riparian vole species (the water vole Arvicola terrestris and root vole Microtus oeconomus) have become scarce since the American mink Neovison vison has established a dense population. Continue reading “Impact of American minks on water vole and root vole populations and populations of the aboriginal predators – eaters of these beneficial prey, in particular, the stoat and great grey owl”
Having pronounced construction instinct and activity, beavers change a lot their aquatic habitats in order to provide foraging pathways protected by water environment and create effective shelters saving them from enemies (mainly wolves and humans) and cold weather during overwintering, giving birth and raising a litter as well as everyday resting.
With respect to semiaquatic mustelids i.e. otter and mink, a question arises do these changes in aquatic habitats bring benefit for them or not? Beavers build a lot of shelters in kinds of burrows and lodges, and such a benefit of better sheltering environment for otter and mink is evident. While investigating the question, we were mainly interested in beaver activity-related increase of water-dwelling prey of otter and mink in aquatic ecosystems and, first of all, in small streams such as small rivers, brooks and drainage canals. Just at small watercourses such an effect of damming by beavers on semiaquatic mustelids may be the most pronounced. By building dams, beavers create ponds; such ponds are gradually eutrophicated and densely overgrown with macrophytes. So, it was essential to get know, such beaver ponds bring benefit in aquatic prey supply for semiaquatic mustelids or not, and if it is, on which stage of the pond eutrophication such benefit is the highest.