Bison Groups Research Articles

March or get infected: Influence of winter ranging shaped by supplementary feeding on the spread of non-native nematode Ashworthius sidemi in European bison populations

Parasitic infections in wildlife are influenced by numerous factors, including those related to wildlife management. This includes sup plementary feeding widespread in numerous ungulates, including European bison. In this paper we analysed the influence of sup plementary feeding and winter ranging of European bison herds on the dynamics, prevalence and infection severity of the blood-sucking nematode Ashworthius sidemi in two areas in NE Poland: the Knyszyn Forest (KF) and the Białowieża Primeval Forest (BPF) with diversified management strategies. We found significant differences in A. sidemi abundance and intensity between European bison groups; sup plementary fed European bison from the BPF had higher parasitic load (3020 parasites, on average), than non-fed individuals from the KF (1400) and from the BPF (770). The prevalence was relatively high in all groups (93–96 %). In the KF the highest infection rate was observed 9 years after the first appearance of A. sidemi, with a maximum value of 8,620 nematodes; while in the BPF, after just 6 years with maximal load up to 44,310 A. sidemi. The most plausible mechanism behind the observed pattern is probably the winter ranging behaviour of differently managed herds. We found that increasing winter home range size of European bison was associated with a significant reduction in the A. sidemi abundance. Our study shows that different management strategies may have an impact on animal spatial behaviour and associated spread and dynamics of pathogens in mammalian populations, and stresses the importance of adaptive management in reducing threats to wildlife.

The Reintroduction Analysis of European Bison (Bison bonasus L., 1758) in the North of Romania and the Identification of the Most Favourable Locations

We analysed the possibility of reintroducing the European bison (Bison bonasus L.) in the north of Romania—in Suceava, Neamț, and Maramureș counties—as well as increasing the wild European bison population in Neamț county to improve the genetic quality of the existing population. Currently, there is a population of over 50 individuals in the wild in Vânători Neamț Natural Park, Romania. At the same time, an attempt was made to identify the connecting corridors between the free European bison in Neamț county and other populations through new nuclei of European bison released in Suceava and Maramureș counties. In this regard, the hunting grounds with the highest ecological potential for the analysed species were identified using GIS spatial analysis techniques. The aim was also to trace possible ecological corridors linking different reintroduction locations, taking into account the ecological claims of the species. The analysis also followed the size of the European bison groups to be released, the sex ratio of each group, and the periodicity of their releasing. In order to reach viable populations, scenarios and simulations were carried out depending on the age, number, and sex of the relocated specimens. In this regard, the dynamics and the minimum viable population that could survive without risk of extinction were highlighted. The analysis showed that the analysed area has a high potential for the reintroduction of European bison in the wild. The release and creation of new European bison nuclei in the wild creates the premises for natural contacts with the existing free populations in the wild, genetic improvement, and increasing fauna diversity with ecological, social, and economic implications.

Benzimidazole resistant Haemonchus contortus in a wildlife park.

Anthelmintic resistance (AR) of ruminant gastrointestinal nematodes (GINs) constitutes a major problem worldwide. Among GINs, the abomasal blood-feeding parasite Haemonchus contortus is particularly pathogenic and may show resistance against all major anthelmintic substance classes. In the present study, the death of a 1,5 year-old European bison (Bison bonasus) from a German wildlife park due to haemonchosis despite frequent anthelmintic treatment of the herd with fenbendazole as well as doramectin prompted an investigation regarding AR. Pooled faecal samples were collected from four different bison groups as well as from mouflons (Ovis orientalis), elk (Alces alces), reindeer (Rangifer tarandus), sika deer (Cervus nippon), Persian fallow deer (Dama mesopotamica) and red deer (Cervus elaphus) housed by the wildlife park. After coproscopical examination, faecal larval cultures were established. Haemonchus contortus-positive larval cultures were further examined for genetic polymorphisms associated with benzimidazole resistance at codons 167 and 200 of the β-tubulin isotype 1 gene by real-time pyrosequencing. Infections with H. contortus were detected in all four bison groups, as well as in mouflons. In five samples, representing two bison groups and the mouflons, the frequency of the resistance-associated single-nucleotide polymorphism (SNP) at codon 200 was 100%. In contrast, resistance-associated SNPs were not detected at codon 167. In addition, faecal egg counts from two bison before and 14 days after parenteral doramectin treatment indicated possible macrocyclic lactone resistance. Detection of anthelmintic resistant nematodes in these animals was especially concerning in the light of planned reintroduction into the wild. As helminth control in zoological gardens and wildlife parks relies mostly on anthelmintic treatment due to restricted possibilities regarding management practices such as rotational grazing, care should be taken to avoid underdosing or unnecessary frequent treatments facilitating the development of AR.

The social network structure of a semi-free roaming European bison herd (Bison bonasus)

The use of social network analysis to better understand animal behaviour has led to an increase in the number of studies on this topic, particularly for species management and conservation as well as the welfare of captive animals. The current knowledge of social organization in the European bison (Bison bonasus) is still largely based on descriptions of group compositions, most of which were obtained during opportunistic field observations. However, the numerous conservation programs for this species can only implement effective management decisions after the analysis of its social structures. For instance, the removal of a key individual can disturb the social stability of a group and thus indirectly affect the fitness of group members. This is the first study that uses social network analysis to examine the social structure of a semi-free ranging bison herd (N = 14). Closest neighbour associations are used to calculate the eigenvector centrality and individual social strength of each animal. These two indices are combined after a principal component analysis (PCA) to form the Sociability variable, which was then tested for correlations with age, dominance rank, number of matrilines and reproductive status (lactating vs non-lactating). Results reveal strong group cohesion, with a close association of individuals belonging to the same matriline within the herd. The cumulative distribution of the eigenvector centralities follows a linear function, meaning that no individual has a highly central position compared to its congeners. Finally, a high Sociability value was not correlated to age, dominance rank or number of matrilines, but was dependent on the reproductive status of females. These results indicate the necessity to consider the social welfare of animals, for instance by taking matrilineal relationships into account when making bison groups management decisions.

Genetic analyses of wild bison in Alberta, Canada: implications for recovery and disease management

In Alberta, wild bison, Bison bison ([Linnaeus 1758][1]) occurring outside protected areas are assumed to have originated from the free-ranging bison populations within Wood Buffalo National Park (WBNP). As bison in WBNP are infected with 2 diseases, it was assumed that neighboring bison outside WBNP were also diseased. However, the neighboring Harper Creek and Ronald Lake bison populations have not tested positive for either disease, suggesting limited contact with WBNP herds. To resolve this, we analyzed microsatellite genotypes from all free-ranging bison groups in Alberta and one from the Northwest Territories (NWT), Canada. In the WBNP area where bison have persisted, we recover a genetically panmictic population comprising all possible subpopulations within the park, plus the adjacent Wentzel Lake herd, all of which are diseased. In contrast, but consistent with their disease-free status, we find the Ronald Lake and Harper Creek bison herds to be genetically differentiated from this larger WBNP herd, despite their close proximity. This highlights the importance of the Ronald Lake and potentially the Harper Creek herds for bison recovery. We also document the genetic impacts of translocation on the species, as the Mackenzie, NWT, and Elk Island National Park (EINP), Alberta, bison populations founded in the 1960s from WBNP animals are now genetically differentiated, but the more recently founded Hay Zama bison population is not differentiated from its source population, the EINP wood bison. Interestingly, factorial correspondence analysis, F ST , and its high private allelic richness suggest that the Harper Creek population is significantly differentiated from all other bison populations studied. Though they are most closely related to WBNP populations, more study of this population is warranted. [1]: #ref-23

Genetic Population Substructure in Bison at Yellowstone National Park

The Yellowstone National Park bison herd is 1 of only 2 populations known to have continually persisted on their current landscape since pre-Columbian times. Over the last century, the census size of this herd has fluctuated from around 100 individuals to over 3000 animals. Previous studies involving radiotelemetry, tooth wear, and parturition timing provide evidence of at least 2 distinct groups of bison within Yellowstone National Park. To better understand the biology of Yellowstone bison, we investigated the potential for limited gene flow across this population using multilocus Bayesian clustering analysis. Two genetically distinct and clearly defined subpopulations were identified based on both genotypic diversity and allelic distributions. Genetic cluster assignments were highly correlated with sampling locations for a subgroup of live capture individuals. Furthermore, a comparison of the cluster assignments to the 2 principle winter cull sites revealed critical differences in migration patterns across years. The 2 Yellowstone subpopulations display levels of differentiation that are only slightly less than that between populations which have been geographically and reproductively isolated for over 40 years. The identification of cryptic population subdivision and genetic differentiation of this magnitude highlights the importance of this biological phenomenon in the management of wildlife species.

Genetic characterization of Northeast Asian cattle based on sequence polymorphisms in the complete mitochondrial genome

In this study, we analyzed complete mtDNA sequences variation and genetic relationship among taurine, indicine and Bison groups. In total, 107 sequences from different breeds, 45 European (45 Italian), 16 Middle East Asian (seven Iranian and nine Iraqi), 41 Northeast Asian (34 Korean and seven Japanese), two Nellore (Bos indicus) and two American Bison bison (Ame. bison) were obtained from Gen-Bank database. One Korean Hanwoo (Bos taurus) sequence was generated using the SOLiDTM System. In total, 1370 polymorphic sites, representing 8.39% of the complete 107 mtDNA sequences (16,338 bp) were detected and of these, 1186 parsimony informative polymorphic sites were identified. Neighbor-joining tree indicated that Korean, Japanese, Iranian, Iraqi, and Italian cattle were closely related to one another, but are separated from B. Bison. The B. taurus mtDNA polymorphism was greater in the D-loop than in the other regions. The ATP8, ND3, ND5, and ND6 regions were also quite parsimony informative, similar to Cyt b. In addition, this study revealed a distinct genetic difference between Korean cattle and B. indicus.

Influence of management practices on large herbivore diet—Case of European bison in Białowieża Primeval Forest (Poland)

Large herbivores are keystone species in many forest areas, as they shape the structure, species diversity and functioning of those ecosystems. The European bison Bison bonasus has been successfully restored after extinction in the wild at the beginning of 20th century. As free-ranging populations of the species were re-established mainly in forest habitats, knowledge of the impact by the largest European terrestrial mammal on tree stands is essential. This helps to make management and conservation decisions for viable population maintenance of the species in the wild. Using a novel DNA-based method of herbivore diet analysis, the trnL approach (DNA-barcoding), we investigated the influence of different foraging conditions (access to supplementary fodder) on bison diet in winter and its potential impact on woody species. Faecal samples were collected from different bison treatment groups: (1) intensively fed; (2) less intensively fed; (3) non-fed utilising forest habitats; and (4) non-fed utilising agricultural areas surrounding the Forest. These were analysed to estimate the proportion of different plant groups consumed by bison. Bison groups differed significantly in their diet. The amount of woody materials (trees and shrubs) consumed by bison increased with decreasing access to supplementary fodder, ranging from 16% in intensively fed bison to 65% in non-fed bison utilising forest habitats. Inversely, the amount of herbs, grasses and sedges decreased from 82% in intensively fed bison to 32% in non fed bison utilising forest habitats. The species of trees mainly browsed by bison, Carpinus/ Corylus, Betula sp. and Salix sp., were of lower economic importance for forest management. The impact of bison on tree species needs further investigation, however, we can predict that browsing by bison, mainly on Carpinus/ Corylus, makes an insignificant impact on forestry due to the high and increasing representation of this species in the forest understory. Supplementary feeding has several negative effects on bison ecology and health, therefore reduced and distributed supplementary feeding should be applied as the management practice in the Białowieża Forest.

Group‐size‐mediated habitat selection and group fusion–fission dynamics of bison under predation risk

For gregarious animals the cost-benefit trade-offs that drive habitat selection may vary dynamically with group size, which plays an important role in foraging and predator avoidance strategies. We examined how habitat selection by bison (Bison bison) varied as a function of group size and interpreted these patterns by testing whether habitat selection was more strongly driven by the competing demands of forage intake vs. predator avoidance behavior. We developed an analytical framework that integrated group size into resource selection functions (RSFs). These group-size-dependent RSFs were based on a matched case-control design and were estimated using conditional logistic regression (mixed and population-averaged models). Fitting RSF models to bison revealed that bison groups responded to multiple aspects of landscape heterogeneity and that selection varied seasonally and as a function of group size. For example, roads were selected in summer, but not in winter. Bison groups avoided areas of high snow water equivalent in winter. They selected areas composed of a large proportion of meadow area within a 700-m radius, and within those areas, bison selected meadows. Importantly, the strength of selection for meadows varied as a function of group size, with stronger selection being observed in larger groups. Hence the bison-habitat relationship depended in part on the dynamics of group formation and division. Group formation was most likely in meadows. In contrast, risk of group fission increased when bison moved into the forest and was higher during the time of day when movements are generally longer and more variable among individuals. We also found that stronger selection for meadows by large rather than small bison groups was caused by longer residence time in individual meadows by larger groups and that departure from meadows appears unlikely to result from a depression in food intake rate. These group-size-dependent patterns were consistent with the hypothesis that avoidance of predation risk is the strongest driver of habitat selection.

Group-size-dependent association between food profitability, predation risk and distribution of free-ranging bison

Predation risk and competition can impose foraging costs, whereas social information acquired from conspecifics may lead to foraging gains. By altering cost–benefit trade-offs of foraging, variations in group size and predation risk can influence plant selection by herbivores. This influence may vary seasonally, depending on how foraging constraints vary throughout the year. Empirical evidence of these combined effects remains limited, especially in natural settings. We evaluated the spatial association between wheat sedge, Carex atherodes, and bison, Bison bison, foraging under predation risk during summer and winter. To maximize their energy intake rate, bison should feed on Carex atherodes. We found that the strength of selection for foraging sites with C. atherodes decreased with increasing risk of wolf, Canis lupus, encounter in winter, but not in summer. Bison faced greater risk in winter than in summer. Selection for C. atherodes was further influenced by group size. Larger bison groups displayed stronger selection for C. atherodes in winter but weaker selection in summer. Seasonal variations in group-size effects can be explained by changes in the relative costs and benefits of social foraging. Bison groups are much larger in summer than winter, implying potentially stronger competition among bison foraging on C. atherodes in summer. Carex atherodes is more inconspicuous in winter than in summer, thereby increasing the value of social information during winter months. We suggest that predation risk and spatial heterogeneity of highly profitable food influence the foraging decisions of bison differently in summer and winter because of seasonal differences in cost–benefit trade-offs.

Sociality, Mate Choice, and Timing of Mating in American Bison (Bison bison): Effects of Large Males

AbstractWe studied group size, composition, and mating activities in American bison (Bison bison) during rut on the Delta Junction Bison Range in interior Alaska, USA, in 1996 and 1997. Our purpose was to determine the effects of large males (≥5 yr old) on mating and associated activities. Groups with large males were larger than those containing smaller males. Most groups of bison were mixed‐sex (90%), but large males occurred in only one‐half of all groups. Moreover, females in groups with large males were more likely to copulate than those in groups with smaller males, indicating a female preference for large males. Nevertheless, our results are consistent with large males seeking out adult females for mating rather than vice versa. Mating peaked in mid‐August during both the study years and was highly synchronous. Scent marking was coincident with mating, an outcome consistent with a hypothesis of such behavior triggering ovulation. Scent marking by large male bison occurred in both male–male and male–female contexts, but was associated most often with sexual activities. No differences in group size occurred with changes in weather or among vegetation types occupied by bison. Group size of bison, however, was larger with increasing distance from the forest edge, which likely was a response to predation risk in this predator‐rich environment.

Bison Grazing Patterns on Seasonally Burned Tallgrass Prairie

Patterns of bison (Bison bison L.) grazing were examined in a 2-year study on a tallgrass prairie site in Oklahoma subjected to a seasonally and spatially variable burning regime. Mixed groups of bison, composed of cows, yearlings, calves, and young ( 5 years of age selected unburned areas for grazing 29% of the time and burned areas only 4% of the time. Temporal patterns in bison grazing were evident; selective use of burns persisted for only a short period during the first post-fire growing season, after which burns were grazed in proportion to availability and then selectively avoided as bison shifted grazing efforts to newer burns. Regression analysis verified that bison grazing was negatively related to burn age. Regression also showed that grazing patterns were positively related to burn patch size. Although burn types varied significantly in biomass and overall vegetative composition, bison exhibited only limited preference for any burn type, choosing those with higher relative cover of annual Bromus spp. and sedges. It appears that bison select recently burned areas with relatively low graminoid biomass for grazing, presumably choosing these areas based on forage quality rather than quantity.

Group structure in wood bison: nutritional and reproductive determinants

Sexual segregation in ungulates has been documented for many species including bison. However, male and female bison do not differ in their pattern of habitat selection. In the present study we observed that a fraction of bison groups did not have young (<2 years) despite the presence of males and females. The male to female ratio in these groups was 2.4. We call them adult groups, in contrast to mixed groups, where young were present and the male to female ratio was 0.4. The proportion of cows with young (mothers) in a group was negatively correlated with the male to female ratio, suggesting that mothers associated more often with other cows than with bulls. Before the rut, cows without young (non-mothers) spent less time feeding than either mothers or bulls. However, mothers and non-mothers did not differ in the number of steps per minute they took while grazing, and both types of cows stepped faster than bulls. We suggest that cows feed more selectively than bulls and that the differing foraging strategies result in temporal but not spatial segregation of the sexes. Possibly as a result of similar nutritional demands, mothers tended to aggregate, forming nursery groups. We suggest that the formation of nursery groups can also serve to protect calves through a dilution effect of predation. Whether mothers actually prefer to associate with other mothers remains to be investigated.

Search or relax: the case of bachelor wood bison

Males of gregarious species of mammals often do not associate with female groups during the breeding season. Such males could leave groups either to search for new breeding opportunities, or to restore body condition before rejoining new female groups. To investigate these two competing hypotheses, we studied the chronology of male wood bison (Bison bison athabascae) associating with females, and their aggressive and sexual behaviour over two breeding seasons. With increasing age, males were more often solitary, were more involved in aggressive interactions, investigated the genitals of females more frequently, and tended females more often. Group size did not affect whether or not males joined or left groups. The presence of oestrous females in a group did not affect the number of bulls in that group, and did not affect the joining or leaving of males. Older, dominant males did not exclude younger ones from female groups. Males observed outside female groups spent relatively more time feeding and resting than bulls in groups. Changes in group composition experienced by a male often involved the joining or splitting of female groups, as opposed to actual transfer of males between groups. Our results suggest that males leave female groups in order to recover, not for the purpose of searching for new female groups. We argue that due to the fluidity of wood bison groups, it is possible for a male to encounter new females even when remaining in a female group.

Serum Biochemical and Hematologic Values of Normal and Mycobacterium Bovis-Infected American Bison

Hematologic and serum biochemical tests were used to monitor the health of 3 groups of bison in an experimental study of tuberculosis. Bison were randomly assigned to Mycobacterium bovis-infected, M. bovis-sensitized, and uninfected control groups. Hematologic measurements included total and differential leukocyte counts, hemoglobin (Hb), packed cell volume (PCV), fibrinogen, and plasma proteins. Biochemical tests included serum urea nitrogen, creatinine, aspartate amino transferase, sorbitol dehydrogenase, serum calcium, and serum phosphorus. There were no significant differences (P = 0.05) in any test values between groups of bison. The bison data were combined and compared to similar data of cattle. The mean values for PCV and Hb were higher than values (PCV 24-46%, Hb 8-15 g/dl) for cattle. Mycobacterium bovis-infected bison had a slight increase in the number of blood monocytes and lymphocytes when compared to the uninfected bison but were within the normal ranges for bison and cattle. Other hematologic parameters were within normal ranges reported for cattle. Creatinine levels in all bison were above the normal range (1.0-1.5 mg/dl) for cattle. Phosphorus levels for M. bovis-infected and M. bovis-sensitized bison exceeded the normal range (5.6-8.0 mg/dl) reported for cattle. The level for uninfected bison was near the upper limit of normal for cattle. Mean values for other serum biochemical tests were within the normal ranges reported for cattle.

Bisoniana XCIV. Strategia użytkowania środowiska przez żubry w Puszczy Białowieskiej

The strategy habitat utilization in the Białowieża Primeval Forest was analysed for mixed groups of bison, which included marked individuals, in the period without snow cover over 1977-1982. In addition to the groups of bulls, which are not analysed in this paper, the basic structural unit is a mixed group.

Fossil Bison and Artifacts From an Early Altithermal Period Arroyo Trap in Wyoming

The Hawken site is a steep-sided arroyo into which small groups of bison were driven and slaughtered. The bison, which date about 4500 B.C. during the Altithermal period, are an extinct variant (B. bison occidentalis) and are morphologically intermediate between B. bison antiquus and B. bison bison. The projectile points are in the Altithermal period Side-Notched tradition and the butchering tools are similar to those found in many bison kill sites from the Paleoindian to the end of the Late Prehistoric period. Continuity of bison procurement methods from Paleoindian through Altithermal and into post-Altithermal times is suggested.