Parasites and associated pathology of the swamp wallaby, Wallabia bicolor (Marsupialia)

Thirty-five swamp wallabies from Victoria, New South Wales and Queensland, Australia were examined for parasites. Thirty-nine species of nematodes, five species of cestodes and eight species of arthropods were found. Wallabies from Queensland and northern New South Wales had a less diverse helminth fauna (23 species) than did wallabies from southern New South Wales and Victoria (32 species). Rugopharynx spp. and Cloacina spp. occurred in large numbers in the stomach but provoked no pathological changes. Known pathogenic species (Globocephaloides trifidospicularis and Hypodontus macropi) were encountered in small numbers only and did not produce any lesions. Pathological changes associated with parasites were: gastric nodules associated with Labiostrongylus clelandi and Parazoniolaimus collaris, bronchopneumonia due to Marsupostrongylus spp., biliary fibrosis associated with Progamotaenia festiva and fibrous peritonitis, pleuritis, pericarditis and eosinophilic splenitis due to Breinlia mundayi. Echinococcus granulosus was the only parasite found which also occurs in domestic animals.     

Chromatid distribution at mitosis in cultured Wallabia bicolor cells

An analysis of labelled centromere regions of chromosomes in metaphase cells of the Swamp Wallaby (Wallabia bicolor) demonstrates conclusively that chromatids do not co-segregate in sets which contain DNA template strands of identical age. Also, there is no tendency for chromatids of homologous chromosome pairs to distribute non-randomly. The data are consistent with the assumption of random distribution of chromatids at mitosis.     

The importance of ecological research for ecosystem management: The case of browsing by swamp wallabies (Wallabia bicolor) in commercially harvested native forests

Summary Ecosystem management often proceeds within the context of sub‐optimal relationships between ecologists and ecosystem managers, and management outcomes could be improved with greater collaboration between members of these disciplines. This paper identifies an ecosystem management problem resulting from the interaction between timber harvesting and browsing wallabies, and this case study is used to exemplify how ecological data and expertise can contribute to the process of ecosystem management. It is argued that appropriate use of existing ecological data, establishment of strategic new research and the implementation of management actions as experimental hypothesis tests can facilitate achievement of management objectives, but greater collaboration between ecologists and managers is required before this can occur. Reasons for sub‐optimal relationships are outlined, and the potential for structural change within large State‐run ecosystem management agencies to improve interactions between managers and ecologists is discussed.     

Comparison of sister chromatid exchanges from three successive cell cycles in Wallabia bicolor chromosomes

An autoradiographic analysis of tritiated thymidine labeled chromosomes of Wallabia bicolor at the second and third metaphases after label incorporations has shown that sister chromatid exchanges (SCE's) from the first and second cell cycles are less than as frequent as SCE's from the third cell cycle after label. Exchange levels per cell cycle estimated at the seconf division are under-estimated due to coincident exchanges. In both methaphases exchanges were largely distributed at random along Wallabia chromosomes with frequencies proportional to chromosome length. The ratio of twin: single SCE's in spontaneoulsy occuring tetraploid cells indicated the first cycle exchanges were marginally more frequent than second cycle exchanges.These data are compatible with exchange probabilities being equal and independent over divisions, but a component of exchanges reducing as tritium content in chromosomes decreases cannot be excluded. This findings that SCE's are primarily independent of tritium cannot be attributed to a saturation of sites for exchange and it is therefore probable that sister exchanges are, in part at least, spontaneous events in Wallabia chromosomes.     

The ecology and macroecology of mammalian home range area

Although many studies employ allometric relationships to demonstrate possible dependence of various traits on body mass, the relationship between home range size and body mass has been perhaps the most difficult to understand. Early studies demonstrated that carnivorous species had larger home ranges than herbivorous species of similar mass. These studies also argued that scaling relations (e.g., slopes) of the former were steeper than those of the latter and explained this in terms of the distribution of food resources, which are more uniformly distributed for most herbivores than for carnivores. In contrast to these studies, we show that scaling relations of home ranges for carnivorous mammals do not differ significantly from those of herbivorous and omnivorous species and that all three exhibit slopes that are significantly steeper than predicted on the basis of energetic requirements. We also demonstrate that home range size is constrained to fit within a polygonal constraint space bounded by lines representing energetic and/or biophysical limitations, which suggests that the log-linear relationship between home range area and mass may not be the appropriate function to compare against the energetically predicted slopes of 0.75 or 1.0. It remains unclear, however, why the slope of the relationship between home range area and body mass, whether based on raw data or on constraint lines, always exceeds that predicted by the energetic needs hypothesis.     

Troop size,home range area and seasonal range use of the Japanese macaque in the Northern Japan Alps

Home range area and habitat use of the wild Japanese macaque (Macaca fuscata) were investigated between elevations of 600m and 3000m in the Northern Japan Alps, in areas where there is great variation in vegetation type. A total of 22 troops were located either visually or by radiotracking from December 1996 to February 2000. The average troop size was 48.4 individuals, the average ranging area (65% probability distribution calculated using the adaptive kernel method) was 3.7km² and the average elevation of each troop varied from 740m to 1458m. Two troop types were distinguished according to their habitat use: (i) rural type groups frequently utilized cultivated land (n=12); and (ii) natural type groups never utilized cultivated land (n=10). Natural groups inhabited higher elevation areas and showed a greater dependency on deciduous broad-leaved forests during all seasons. In contrast, rural groups utilized the larch plantation more in spring, and the red pine forest in summer. Rural groups were observed on cultivated lands more often from summer to winter than in spring. The size of the rural groups was twice as large as that of the natural groups. Troop size and home range area showed significant correlation within each group type. The per capita home range area of rural groups was smaller than that of natural groups. These results suggest that per capita home range area is negatively correlated with habitat quality.     

Seasonal home range shift of red deer in a forest-agriculture area in southern Hungary

A long-term radiotelemetry study on red deerCervus elaphus Linnaeus, 1758 was carried out in a lowland forest-agriculture area in Hungary between 1993–2000. Previous observations suggested seasonal changes in population distribution between forested and agricultural habitat. Red deer concentrated in the forest during winter, but they appeared in the agricultural field during the vegetational period. We investigated the ranging behaviour, testing two alternative hypotheses: home range expansion and home range shift. Weekly radiotelemetry localisations revealed that 9 of 28 hinds showed a clear home range shift from the forest to the agricultural area for a prolonged time during the vegetational period. The remaining portion of the animals used a home range within the forest throughout the entire year. Diet composition analysis using indicator plant species showed that neither daily passages between habitats, nor home range expansion exists. These ranging behaviours were stable hence, if an animal shifted one year it shifted again in consecutive years andvice versa. Our results could be useful for the successful management of red deer populations in such complex habitats and to decrease agricultural damage.     

A model for relating troop size and home range area in a primate species

For relating troop size (N) and home range area (R), a simple model,QR=αN, whereQ denotes habitat quality and α is a constant, was examined using published field data forMacaca fuscata, M. mulatta andColobus guereza. In particular, theN-R direct proportionality of the model was tested for its validity and usefulness in comparison with a few less simple models. The implications of the present model are discussed in relation to bioenergetics and population dynamics.     

On the nature of the opaque and translucent enamel regions of some macropodinae (Macropus giganteus,Wallabia bicolor and Peradorcas concinna)

Summary Teeth of three macropod species, M. giganteus, W. bicolor and P. concinna, have been studied using the techniques of light microscopy, scanning- and transmission-electron microscopy and hardness measurement. Light microscope observations showed that the teeth of these species had a translucent enamel region close to the dentine and an outer opaque enamel region at the tooth's surface. These regions were not related to the presence or absence of tubules which are a characteristic feature of marsupial enamel. Hardness tests showed that the opaque enamel was softer than the translucent enamel. Scanning electron microscope observations revealed that there was no correlation between any particular prism packing or orientation and the opaque and translucent enamel regions. Transmission electron microscope observations showed that the translucent enamel region consisted of well defined prisms and well packed, lath-like crystals, whereas the opaque enamel was disrupted by voids (which ranged in size from enlarged micropores to about 2 m in diameter in extreme cases) between crystals and some randomly oriented, loosely packed crystals. This disruption within the opaque enamel region was more common at prism boundaries but pockets of disrupted enamel were also found within prisms and interprismatic regions. The opacity of the enamel was caused by scattering of light from the voids. The ultrastructure of the opaque enamel region indicated that this region was hypomineralized; hardness tests and polarized light microscope observations were consistent with these results.     

One century away from home: how the red swamp crayfish took over the world

Reviews in Fish Biology and Fisheries - The red swamp crayfish (Procambarus clarkii) (hereafter RSC), native to the southern United States and north-eastern Mexico, is currently the most widely...     

Habitat use, home range and foraging preferences of the coati Nasua nasua in a pluvial tropical Atlantic forest area

Coatis (genus Nasua ) occupy a large range of forested habitats. The aim of this study was to describe the use of habitat by Nasua nasua in a continuous pluvial tropical Atlantic forest area, the Carlos Botelho State Park (CBSP) in south-eastern Brazil. Use of space by N. nasua in the CBSP was characterized by an average home range area for one group of 445 ha by the minimum convex polygon method and 544 ha by the fixed kernel method, which was used across 2 months; the use of trees for foraging and travelling was superior to that reported for N. nasua and Nasua narica until now, being higher in the drier season. The home range of three coati groups shifted during the 3 years of this study; the home range of one habituated group changed by 91%. The proportion of ground foraging increased with the higher availability of soil invertebrates during the rainy season, but cannot be explained solely on the basis of resource availability.     

Factors influencing home range and activity of wild boar (Sus scrofa) in a Mediterranean coastal area

This paper analyses the temporal variation in the size of home range and activity of adult wild boar ( Sus scrofa L.). Eighteen boar were radiotracked between 1991 and 1993 in the Maremma Natural Park (Central Italy). Variations of home-range size and activity were related to sex, winter food availability and population density. The hypotheses that home-range size was inversely related to food availability and population density, and that the amount of activity was directly related to population density and inversely related to food abundance, were tested. The size of the acorn crop was used as a measure of winter resource level. No differences were found in the size of ranges, core area, and activity between males and females. In 1991–92 home-range size was larger than in 1992–93; conversely, activity increased from 1991–92 to 1992–93. Winter food availability was high in 1991–92 and low in the following year. Population density increased greatly in spring 1992 but crashed in spring and summer 1993, when a high mortality of wild boar occurred due to starvation.
The decrease in home-range size during the food shortage was explained as a possible strategy adopted by wild boar to cope with starvation. The difference in home-range size and amount of activity found between the first and the second year of study were probably influenced by differences in population density, although the individual effects of food availability and population density were not clearly separable.     

Plant species coexistence at local scale in temperate swamp forest: test of habitat heterogeneity hypothesis

It has been suggested that a heterogeneous environment enhances species richness and allows for the coexistence of species. However, there is increasing evidence that environmental heterogeneity can have no effect or even a negative effect on plant species richness and plant coexistence at a local scale. We examined whether plant species richness increases with local heterogeneity in the water table depth, microtopography, pH and light availability in a swamp forest community at three local spatial scales (grain: 0.6, 1.2 and 11.4 m). We also used the variance partitioning approach to assess the relative contributions of niche-based and other spatial processes to species occurrence. We found that heterogeneity in microtopography and light availability positively correlated with species richness, in accordance with the habitat heterogeneity hypothesis. However, we recorded different heterogeneity-diversity relationships for particular functional species groups. An increase in the richness of bryophytes and woody plant species was generally related to habitat heterogeneity at all measured spatial scales, whereas a low impact on herbaceous species richness was recorded only at the 11.4 m scale. The distribution of herbaceous plants was primarily explained by other spatial processes, such as dispersal, in contrast to the occurrence of bryophytes, which was better explained by environmental factors. Our results suggest that both niche-based and other spatial processes are important determinants of the plant composition and species turnover at local spatial scales in swamp forests.     

The effect of season, sex and feeding style on home range area versus body mass scaling in temperate ruminants

Sex-specific estimates of the summer and winter home range area of 19 species of temperate ruminants were collated from the literature. It was predicted that there should be a shallower slope for the home range area against body mass relationship during winter than during summer, as large ruminants can meet more of their energy requirements from the fat reserves deposited during summer than small ruminants. Consequently, relatively large species do not need to range as widely during winter. There was a significant positive relationship between body mass and summer and winter home range area in both females and males. This relationship remained significant when analysed within feeding styles (browser, mixed feeder, grazer), except in mixed feeders in winter. As predicted, slope estimates were significantly lower during winter (b=0.59) than during summer (b=1.28), both before and after controlling for phylogeny. After controlling for phylogeny, browsers had a steeper slope (summer: b=1.48; winter: b=1.07) of the home range area against body mass relationship than did mixed feeders (summer: b=0.75; winter: b=-0.11) or grazers (summer: b=1.10; winter: b=0.34). There was no effect of sex after body mass was controlled for. The effect of season, sex and feeding style on the home range area versus body mass relationship in temperate ruminants is discussed.