Jörn Theuerkauf

Spatiotemporal segregation of wolves from humans in the bialowieza forest (POLAND)

Knowledge about the impact of human activity on the behavior of wolves (Canis lupus) is important to predict habitats suitable for wolf recolonization and for planning management zones. We tested the hypothesis that wolves live spatiotemporally segregated from humans. From 1994 to 1999, we radiotracked 11 wolves in 4 packs and monitored human activity in the Bialowieza Forest, Poland. Wolves avoided permanent human-made structures (settlements, forest edge to arable land, roads, tourist trails) more in the day than at night. Wolf avoidance increased with increasing human use. Particularly large settlements and intensively used public roads reduced the area used by wolves. Wolves avoided human presence in the forest (traffic, forestry operations) by temporarily selecting areas where people were absent. One of the wolf packs selected a national park zone with restriced access (50 km 2 ) as the core area of its home range in both day and night. Conversely, wolf packs living in a commercial forest with small nature reserves (≤4 km 2 ) did not select reserves in the day or night. We concluded that spatiotemporal segregation is an adaptation of wolves to coexist with humans while keeping their activity pattern optimized toward food acquisition. The distribution of areas with restricted human access, forest, settlements, and intensively used public roads are important factors determining the suitability of an area for wolves.

Genetic diversity and relatedness within packs in an intensely hunted population of wolvesCanis lupus

A population of grey wolvesCanis lupus Linnaeus, 1758 inhabiting Białowieża Primeval Forest (BPF) on the Polish-Belarussian border has recovered after near extermination in the 1970s. Currently, it is intensively hunted in the Belarussian part of BPF and protected in the Polish part. We used a combination of molecular analysis, radiotracking, and field observation to study genetic diversity of the population after natural recolonisation and the consequences of heavy hunting for the genetic composition and social structure of wolf packs. Both microsatellite and mtDNA analyses revealed high genetic diversity. For 29 individuals and 20 microsatellite loci, the mean expected heterozygosity was 0.733. Four mtDNA haplotypes were found. Three of them had earlier been described from Europe. Their geographic distribution suggests that wolves recolonising BPF immigrated mainly from the north-east, and less effectively from the east and south-east. We traced the composition of 6 packs for a total of 26 pack-years. Packs were family units (a breeding pair with offspring) with occasional adoption of unrelated adult males, which occurred more frequently in packs living in the Belarussian part of the BPF, due to heavy hunting and poaching. Breeding pairs were half-sibs or unrelated wolves. Pair-bonds in the breeding pair lasted from 1 to 4 years and usually broke by the death of one or both mates. Successors of breeding females were their daughters, while a successor of a breeding male could be either his son or an alien wolf. As is evident from Białowieża’s wolves, high genetic diversity may result from immigration of outside individuals, which are easily recruited to a heavily exploited local population.

Factors determining the distribution of introduced mammals in nature reserves of the southern province, New Caledonia

We studied the distribution of introduced mammals in six nature reserves of New Caledonias southern province. Polynesian rats (Rattus exulans) were common in both rainforest and shrubland but their abundance decreased with increasing altitude. Ship rats (Rattus rattus) were abundant in rainforest but less numerous in shrubland and their abundance did not increase with altitude. We found no Norway rats (Rattus norvegicus) or house mice (Mus musculus domesticus) in reserves. Feral pigs (Sus scrofa) used mainly rainforest but also shrubland and preferred foraging in valleys with alluvial soils. Rusa deer (Cervus timorensis) selected shrubland over rainforest. Feral cats (Felis catus) were widely distributed in the reserves, whereas dogs (Canis familiaris) strayed into reserves but did not form feral populations.

Accuracy of radiotelemetry to estimate wolf activity and locations

We analyzed radiotracking data from wolves (Canis lupus) in the Bialowieza Forest, Poland, to determine (1) differences between methods of estimating mean wolf activity and daily activity patterns, (2) whether activity estimated by changes in signal strength is dependent on the distance between the radiotracked wolf and the tracker, (3) radiotracker influence on wolf activity estimates, and (4) accuracy of radio locations. Daily patterns of wolf activity estimated by changes in signal strength, movements, and activity sensors were similar. However, the mean time spent active estimated by changes in signal strength (55% of the time) was higher than those estimated by movements (34%) or sensors (32%). We obtained the most accurate estimates of activity by a combination of movement, signal strength, and sensor data (43%) or by combining movement and signal strength data (44%). Activity estimated by changes in signal strength did not vary with the distance between radiotracked animals and radio-trackers. The trackers had no detectable influence on activity and movements of wolves when the tracker-to-wolf distance was >200 m. There was a small but not significant influence if trackers were <200 m away during the day. The mean radiotracking error was 194 m (95% CI: 157-231 m). We recommend that data on movements always be included in estimates of mean time spent active because activity sensors lead to underestimates and changes in signal strength to overestimates. Distances traveled obtained by radiotracking should not be regarded as minimal distances traveled, since the likelihood that they are overestimated or underestimated depends on the relation between the accuracy of radio locations and the mean distance that an animal travels per radiotracking interval.

Cooperative breeding, mate guarding, and nest sharing in two parrot species of New Caledonia

We provide evidence for cooperative breeding in two endemic parrot species of New Caledonia, the New Caledonian Parakeet (Cyanoramphus saisseti) and the Horned Parakeet (Eunymphicus cornutus). We intensively monitored 11 breeding attempts in two nests of New Caledonian Parakeets over 5 years, and noticed that two males of different size fed the female and the chicks in each nest. During one breeding attempt, the larger male guarded the female and the smaller male tried to copulate with her inside the nest. Genetic analyses showed that males shared paternity. During 17 breeding attempts in 11 Horned Parakeet nests, we observed two pairs sharing a nest on one occasion but we never saw feeding helpers.

Do Orthoptera need human land use in Central Europe? The role of habitat patch size and linear corridors in the Białowieża Forest, Poland

We studied Orthoptera, Dermaptera, and Blattodea of the Bial.owieza Forest (Poland) in order to assess (1) the minimum patch size of open habitat necessary for each species, (2) the role of linear corridors as habitat, and (3) the impact of herbivores on diversity by comparing the fauna at periods of different ungulate densities. Many species occurred in the farthest clearings from the forest edge to arable land. Two third of species occurred in clearings smaller than 10,000 m2. Dry linear corridors of 10–40 m width and wet linear corridors of 100–200 m width had a species richness that corresponded to that of clearings of about 10,000 m2. Four species disappeared from the Bialowieza Forest when ungulate density decreased from 20 individuals/km2 (3000 kg/km2 biomass) at the beginning of the 20th century to 10 individuals/km2 (1000 kg/km2) at the end of the 20th century. We conclude that most Orthoptera, Dermaptera, and Blattodea species could survive in Central Europe if human land use was replaced by intensive grazing and browsing by wild herbivores.

Group Territoriality as a form of Cooperative Breeding in the Flightless Kagu (Rhynochetos jubatus) of New Caledonia

ABSTRACT. Birds that live in family groups and cooperatively defend the familys territory are currently recognized as cooperative breeders only if helpers assist with chick rearing. We observed breeding Kagus (Rhynochetos jubatus) and video-monitored nests to determine whether help with feeding or family size affected their reproductive success. During >5,500 h of nest monitoring, helpers never provided parents or chicks with food. The reproductive success of families increased with group size nonetheless. Family size affected breeding success more than habitat-related parameters. Nonbreeding Kagus reacted to playback calls as often as breeding birds did. Observations of territorial fights gave additional evidence that nonbreeding group members help defend the familys territory and can, therefore, improve reproductive success. Our results suggest that cooperative territory-defense was the most important factor that increased the breeding success of Kagus. We propose that group territoriality should be considered a form of cooperative breeding.

Detectability and Disappearance of Ungulate and Hare Faeces in a European Temperate Forest

We counted droppings of ungulates and hare on transects in order to assess (1) seasonal changes in detectability and disappearance of pellet groups, (2) whether the detectability varies according to the forest type, and (3) the degree of misidentification between pellets of roe deer (Capreolus capreolus) and red deer (Cervus elaphus). The summer decrease in detectability of pellet groups was the most important factor for all species but European bison (Bison bonasus). Detectability did not significantly depend on forest type. In summer, decay reduced significantly the dropping density of red deer, roe deer, wild boar (Sus scrofa) and European hare (Lepus europaeus) but not those of bison and moose (Alces alces). Misidentification of roe and red deer droppings did not influence much density estimates of red deer but resulted in an important overestimation of roe deer in areas were roe deer were much less common than red deer.

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.

The need for standardization in wildlife science: home range estimators as an example

Individual studies in wildlife science are indicative rather than conclusive. Although multiple studies can be meta-analyzed in such a way that scientific hypotheses can be tested, robust meta-analyses are often difficult or impossible if variables of interest are not measured in a uniform manner. We hypothesized that measurements, even of basic and unequivocal variables, are rarely standardized in wildlife sciences. We tested this assumption by reviewing randomly selected papers that describe the home range of mammals (n = 25) and birds (n = 25). In these papers, home ranges were calculated using 11 methods and 8 computer programs. The number of radiolocations used to calculate home ranges varied from 9 to >2,000. By estimating home ranges for two radiotelemetry data sets, we demonstrate that home ranges are not comparable if different methods are used and that estimates of home range are not standardized. We assume that measurements of other biological variables are even less consistent across studies. In order to advance wildlife sciences, we believe that standardization initiatives are required at an international level.