Reproductive behaviour of wild-living wolves in Białowieża Primeval Forest (Poland)

Characteristics of the reproductive behaviour of wolves (Canis lupus) were studied by radio-tracking and snow-tracking of four packs in Białowieża Primeval Forest (BPF), Poland, in 1995–1999. Signs of mating occurred between 12 January and 22 March. Parturition occurred between 19 April and 12 May, and the denning period lasted for 49–64 days. During that time, wolves used 1–3 den sites, spending on average 27 days at each site. The dens were never reused in consecutive years, but year after year the breeding sites were located in the same parts of the pack’s territory. Ten days before parturition pregnant females reduced their normal mobility by half (from 23 to 13.5 km day⁻¹, on average). During the ten days post-partum, they spent 85% of their time with pups and travelled 3.9 km day⁻¹, only. On days 11–30 after parturition, females spent 74% of their time tending pups and increased their daily movement distance to a mean of 13.3 km. The females resumed full mobility 50–70 days after parturition, which coincides with termination of the weaning process. Anecdotal observations indicated that pups were tended by other pack members while the mother was absent. Compared with the years 1947–1950, in 1995–1999 the breeding season of wolves in BPF occurred two weeks earlier. A possible reason was the 1 to 1.5-degree increase in the mean annual temperature during the last 50 years.     

The process of a wolf pack splitting in Białowieża Primeval Forest,Poland

In 1998, the pack of 7 wolvesCanis lupus Linnaeus, 1758, radio-tracked in Białowieża Primeval Forest, East Poland, split into 2 packs (2 and 5 wolves), when an 8-year-old alpha female ceased breeding. The two sister-packs subdivided their original territory, but their ranges overlapped extensively (49%) for one year after the split, except for May-June, when both new packs reared pups. We propose that food related factors could have been the ultimate cause of splitting of a large pack. In European temperate forests, pack size of 5–6 wolves is optimal for the consumption of the red deerCervus elaphus.     

Species composition and activity of bats flying over rivers in the Białowieża Primeval Forest

Bats were netted at two sites over the forest rivers Narewka and Hwoźna in Białowieża Primeval Forest (E Poland), during the summer of 1994 and 1995. A total of 452 bats of 11 species were captured. The number of bats netted each night was positively correlated with the minimum air temperature. The rate at which the three commonest species —Nyctalus noctula, Myotis daubentonii andNyctalus leisleri — were caught varied significantly through the night, with a major peak after sunset. ForN. noctula air temperature was apparently positively related to the size of the morning peak.     

Soil and vegetation nutrient response to bison carcasses in Białowieża Primeval Forest,Poland

Ungulate carcasses can have important effects on the surrounding soil and vegetation. The impact of six carcasses of European bison (Bison bonasus) was investigated for the first time in a natural temperate forest (Białowieża, Poland) by measuring soil and plant nutrient concentrations along a gradient extending from the centre of each carcass. Calcium concentration and pH were found to be higher at the centre of the carcass, decreasing towards the periphery. This effect lasted up to 7 years after the death of the animal. The concentration of most nutrients in the soil and plants varied irregularly, suggesting an effect of the carcass at its centre but the absence of a clear pattern of variation along the gradient. Concentrations of NO₃⁻ in the soil differed only at the 1-year old carcass, suggesting a fast turnover of nitrate in temperate forests. Our results show that the effects of large herbivore carcasses on soil and plant nutrient concentrations are not easily detectable in a temperate forest as in more homogeneous habitats, such as tundra and prairie. This may be due to the high activity of scavengers and nutrient recycling in the study area, but it may also be a consequence of a more complex and patchy interaction between nutrient availability and other limiting factors in temperate forests.     

Spatial interactions between grey wolves and Eurasian lynx in Białowieża Primeval Forest, Poland

Various species of large predators are reported to influence each other through interference or exploitation competition that may affect demography and survival of the subordinate species. We analyzed spatial relationships between grey wolf (Canis lupus) and Eurasian lynx (Lynx lynx) in Białowieża Primeval Forest (BPF, eastern Poland) to determine how they partitioned the space. The wolves (n = 8) and lynx (n = 14) were radio-tracked in 1991–1999. Three wolves and seven lynx were radio-tracked simultaneously in 1994–1996. Territories of wolf packs and home ranges of lynx overlapped considerably (76% of wolf territories and 50% of lynx home ranges, on average). In three cases, their core areas were also overlapping. Wolf-lynx dyads with overlapping home ranges were simultaneously located at distances from 0 to 28 km from each other. We found neither avoidance nor attraction between wolves and lynx occupying the same areas. We concluded that in BPF, the two large predators coexist due to specialization on different preferred prey and heterogeneous habitat.     

The mosaic diversity of field layer vegetation in the natural and exploited forests of Białowieża

The main focus of the study was to find out whether and how the forestry management in the Biaowiea Forest has influenced the mosaic diversity of field layer vegetation and habitat heterogeneity in the temperate hard wood forest (Tilio-Carpinetum). Five belt-transects represent natural and semi-natural old-growths in Biaowiea National Park (BNP), the commercial forest (CF), and secondary stands in the CF. Along the transects, distinct patches of field layer vegetation were identified and delimited, and their species composition was assessed. Along central lines of the transects the environmental data was collected from sample points established at regular intervals: soil pH and the distances to the 4 closest trees, their species, and dbh (diameter at the breast height=135 cm). The group of patches (on average 50 per transect) was subjected to the dichotomous classification in order to identify a number of characteristic types of microphytocoenoses – synusiae. Beta-diversity of the vegetation was expressed with the Simpson diversity index calculated on the basis of areas occupied by synusiae. The most structurally diversified were the transects representing natural old-growths in the BNP. A calculation of similarity coefficients between the transects on the basis of their mosaic composition displayed sharper differences between old-growth and secondary communities in summer than those found in spring. Forestry management has seriously modified the tree species composition in two studied stands, through planting oak or initiating succession. This resulted, both in plantation and pioneer stand, in loss of the main components of natural old-growths: hornbeam (Carpinus betulus), Norway spruce (Picea abies), lime (Tilia cordata) and maple (Acer platanoides). Significantly a wider range of soil pH values in natural old-growths coincided with a higher diversity of herbaceous mosaics comparing to secondary stands. The elimination of spruce (the species being most commonly blown down, projecting an acid canopy shadow) in two studied areas, elimination of dead wood, and destruction of humus layers through ploughing, could contribute to a reduction of specific microenvironments. A lower mosaic diversity of secondary stands coinciding with the unification of environmental conditions along the transects may indicate that forestry management can lead to the disappearance of a highly structural character in natural forest communities.Nomenclature: Flora europaea; Sokoowski (1993).     

Sarcoptic mange vulnerability in carnivores of the Białowieża Primeval Forest,Poland: underlying determinant factors

Sarcoptic mange caused by Sarcoptes scabiei, is a highly contagious worldwide mite infection responsible for epizootic skin disease in populations of wild and domestic mammals. It causes skin disorders that may lead to severe generalized skin disease (mange). We investigated the spread and dynamics of sarcoptic mange in one of the best preserved carnivore communities in the Bia?owie?a Primeval Forest over the last 20 years. Sarcoptic mange was found in 6 of 10 investigated species. The highest percentage of infected individuals was recorded in red foxes (19 %), European badgers (9 %), grey wolves (7 %), raccoon dogs (6 %), and stone martens (5 %). Other species were not infected (least weasel, American mink, European polecat, pine marten) or infected sporadically (Eurasian lynx––1 case). Rate of infection was correlated with the sum of ecological and behavioral features, which may increase the spread of infection. Outbreaks of sarcoptic mange occurred simultaneously in several species of carnivores, which indicates the occurrence of between species transmission. We found that the source of investigated individuals (trapped, culled and found dead) may influence the results of the analysis. Our study shows that in carnivore communities such as in Bia?owie?a Forest, numerous species may serve as a reservoir of the pathogen and favor its persistence in the environment. This study indicates that sociality and use of den sites are important factors affecting sarcoptic mange spread and prevalence in wild populations of carnivores.     

Accuracy of radio-tracking to estimate activity and distances walked by European bison in the Bialowieża Forest, Poland

To determine the accuracy of radio-tracking estimates of activity and distances walked by European bisonBison bonasus (Linnaeus, 1758), we observed bison while simultaneously conducting radio-tracking in the Bialowie?a Forest (Poland). Single radio-tracking estimates often did not represent the actual activity of the bison, but the mean time spent active calculated from radio-tracking and direct observations did not differ significantly. Radio-tracking provided overestimates of the distances walked by bison when the animals walked between 0 and 25 m and underestimated the distances walked by bison if they walked further than 25 m in a radio-tracking interval. Activity was best estimated when radio-trackers were between 200 and 300 m from the bison. The mean activity calculated with a sampling interval of 15 min needed about 8 days of radio-tracking and the mean of distances walked about 35 tracking days to stabilise. We concluded that collars without activity sensors can measure the mean activity of bison but cannot represent the length of their activity bouts or the type of their activity and that our radio-tracking estimates of distances walked by bison needed to be corrected before further analyses.     

Wolf predation and snow cover as mortality factors in the ungulate community of the Bialowieża National Park,Poland

Summary Wolf-ungulate interactions were studied in the pristine deciduous and mixed forests of the Bialowiea National Park in 1985–1989. The study period included two severe and two mild winters. The community of ungulates inhabiting Bialowiea National Park consisted of red deer Cervus elaphus, 55% of all ungulates; wild boar Sus scrofa, 42%; and roe deer Capreolus capreolus, moose Alces alces, and European bison Bison bonasus, about 1% each. The average size of red deer groups increased from 2.7 (SD 2.35) in spring and summer to 6.9 (SD 6.84) in autumn and winter. In winter the group size of red deer was positively correlated with the depth of snow cover and negatively correlated with the mean daily temperature. Average group size of wild boar did not change significantly between seasons; it was 6.8 (SD 5.16) in spring and summer and 5.7 (SD 4.67) in autumn and winter. Analysis of 144 wolf scats showed that wolves preyed selectively on red deer. In October–April, Cervidae (mostly red deer) constituted 91% of biomass consumed by wolves, while wild boar made up only 8%. In May–September deer formed 77% of prey biomass, and the share of wild boar increased to 22%. In all seasons of the year wolves selected juveniles from deer and boar populations: 61% of red deer and 94% of wild boar of determined age recovered from wolves' scats were young <1 year old. Analysis of 117 carcasses of ungulates found in Bialowiea National Park showed that predation was the predominant mortality factor for red deer (40 killed, 10 dead from causes other than predation) and roe deer (4 killed, none dead). Wild boar suffered most from severe winter conditions (8 killed, 56 dead). The percentage of ungulates that had died from undernutrition and starvation in the total mortality was proportional to the severity of winter.     

Seasonal and sexual variation in diel activity rhythms of pine martenMartes martes in the Białowieża National Park (Poland)

From 1991–1996, the activity rhythms of 14 radio-collared pine martensMartes martes (Linnaeus, 1758) (6 males and 8 females) were studied in the pristine deciduous and mixed forests of the Białowieża National Park. Tracking data (5823 h) indicated that the activity rhythms of pine martens varied between sexes and seasons. In spring, male activity peaked at 20.00–00.00 h, whereas in summer and autumn-winter, activity was bimodal, peaking at 18.00–22.00 h and 02.00–04.00 h. Female activity in spring was more evenly distributed than that of males, but in summer their activity peaked at 20.00–00.00 h, while in autumn-winter females had a bimodal rhythm with peaks at 18.00–20.00 h and 02.00–06.00 h. In breeding females, activity rhythms changed in the course of pregnancy and nursing. On average, martens started their activity 73±209 (SD) min before sunset and finished 87±245 min after sunrise. Females became active earlier than males but both sexes terminated activity at the same time. For both males and females the daily activity rhythm was not related to the diurnal course of temperature.     

The regressive Cirsium rivulare population in an unmown meadow in Białowieża National Park: Influenced by other clonal plants and necromass

This study deals with population dynamics of Cirsium rivulare (brook thistle) present in a meadow that undergoes succession as a result of former disuse. The effect of the following in the succession, currently dominant clonal species and necromass on the performance of the brook thistle population (presence, size of clusters and reproduction) was investigated. The regression stage, the Cirsium rivulare population had attained after mowing, was discontinued. Different kinds of influence from the contiguous species on the brook thistle population could be identified. In the case of Filipendula ulmaria and Carex cespitosa, Cirsium rivulare clusters were found to be present on the edge of the dominant patches. In case of Carex acutiformis patches brook thistle ramets did not form clusters but were present among the sedge ramets. No Cirsium rivulare ramets were found in Phragmites australis and willow (Salix cinerea, S. pentandra and S. aurita) patches. The highest number of generative brook thistle ramets were observed in a Carex acutiformis patch, whereas the highest number of inflorescences on the shoots of the analysed species were identified in the patch dominated by Filipendula ulmaria.Experimental vegetation gaps were created in patches dominated by various species to determine the effect of necromass on the presence of Cirsium rivulare seedlings. A considerable rise in the number of Cirsium rivulare seedlings was noted in Carex acutiformis and Filipendula ulmaria patches following necromass removal in comparison with plots containing necromass. On the other hand, removing the necromass and foliage did not contribute to an increase in the numbers of brook thistle seedlings in the patch dominated by Cirsium rivulare itself.     

Chrysomelid communities (Chrysomelidae, Coleoptera) of xerothermic grasslands (Inuletum ensifoliae) in the Wyżyna Miechowska Uplands (Central Poland)

The species composition, abundance and dominance structure of chrysomelids were characterized in xerothermic grasslands in southern Poland (Wyżyna Miechowska Uplands). During a two-year study, a total of 54 species was recorded; the mean value of the abundance index was 9.3, Longitarsus obliteratus and Derocrepis rufipes being eudominants. The species composition and quantitative structure of the community were similar (S = 80.0%, Re = 70.5%) but diversity, evenness and dominance indices of the community changed slightly although the abundance dynamics of the beetles varied significantly in the study years.