摘要:

AbstractThe diversity, abundance and display characteristics of plants producing fleshy fruits were recorded in wet sclerophyll forest near Melbourne, Victoria. Fruit characteristics and nutrient content were recorded for 14 species of fruits occurring in the forest and these characteristics compared with similar studies in north temperate and tropical regions. Plants producing fleshy fruits were confined to understorey layers and comprised 13.5% of the native vascular flora. Most species displayed fruits conspicuously by ripening brightly coloured fruits synchronously in large displays. Annual fruit production at three sites ranged from 6.98 to 37.01 kg/ha. Fruit mass, seed number and size were variable but the proportion of pulp per fruit remained remarkably consistent between species. Most fruit pulp contained high quantities of soluble carbohydrates and little lipid or protein. Fruits from wet sclerophyll forest did not differ from fruits from other geographic areas in eight characteristics measured. Although taxonomically distinct, the species in wet sclerophyll forest were not significantly different from other temperate fruits, suggesting that fruit characteristics are under the influence of factors other than phylogeny.

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1991.tb01476.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe habitat preference and impact of banteng (Bos javanicus) and pigs (Sus scrofa) in Gurig National Park, on Cobourg Peninsula, Northern Territory, was investigated by systematically sampling twelve habitats. Animal signs (banteng and pig scats) and impacts (area of rooted, trampled or pugged ground and number of rubbed tree trunks) were recorded in 696 quadrats, each 5 × 20 m. Significant differences among habitats in sign and impact were detected. Pig rooting was concentrated on wetland communities, particularly sedgelands. Banteng sign focused on monsoon forest and coastal plains, where they caused less obvious damage than pigs. There was little evidence of either ungulate in the eucalypt communities, which are the most widespread of all habitats on the peninsula.In monsoon forests, banteng densities were approximately 70 per km‐2, Banteng, unlike pigs and buffalo, have remained near their point of introduction over the last 140 years, possibly because of the unique habitat mosaic consisting of grasslands abutting monsoon fore

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1991.tb01477.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractPitfall trapping was used in commercial Mountain Ash (Eucalyptus regnans) regrowth forest to study the effects on epigeal arthropods of high‐intensity wildfire plus salvage logging, and of harvesting by clearfelling plus slash burning, followed by fire‐induced natural or artificially established regeneration respectively. The study, the first of its kind in the Victorian Central Highlands, 60 km east of Melbourne, was based on 146 922 specimens of 30 ordinal or lower level taxa collected over a 3‐year period. The abrupt replacement of the ecologically complex regrowth forest by ecologically much simpler even‐aged regeneration caused appreciable instability among the litter‐frequenting arthropods. An immediate decline in diversity occurred due to short‐term boosts in activity of some common ‘major’ taxa (notably a species of seed‐harvesting ant) and the suppression of other taxa. A broad mix of functionally diverse taxa reappeared within two years of regeneration, and all but three rarely trapped ‘minor’ taxa present in undisturbed 43–46 year old regrowth (‘control’) forest had returned within 5 years. Epigeal arthropods therefore appeared to be affected only over a short period relative to the nominal 80–150 year rotation of theE. regnansecosystem. Research is needed at the species level to achieve a more precise assessment of arthropod responses to

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1991.tb01478.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe effects of logging on three species of common skinks were estimated from censuses in four age classes of forest: unlogged, just logged, 1‐year logged and 10–15 year regrowth. The effects of topography (ridge and gully) were examined in each age class. Afire in November 1980 occurred fust after the initial census was completed. Another census was taken in December 1980 to assess its immediate effects. Further censuses were carried out each December from 1981 to 1984. An intense drought overlapped from 1980 to 1983 with the census period. Lampropholis guichenoti occurred in about equal numbers in unlogged and recently logged forest, but its numbers were reduced in the 10–15 year regrowth forest. This was attributed to changes in the amount and pattern of sunlight reaching the ground. A similar pattern of response was found for Lampropholis delicata. The numbers of Eulamprus heatwolei, a gully species requiring partial shade, were lowest in the exposed, recently‐logged forest, but had increased in the 10–15 year regrowth class to about equal their numbers in unlogged forest. Fire reduced the numbers ofL. guichenoti on ridges but had no immediate impact on numbers of tire other species, while drought markedly depressed numbers of all species. Lampropholis guichenoti recovered more quickly from the drought than did L. delicata, but the numbers of E. heatwolei were still declining 19 months after the drought broke. The drought also revealed a habitat (ridge/gully) difference between the two Lampropholis species. The management of these species in commercial forests requires that some areas, particularly gullies, be reserved and the logging sequence modified to prevent the creation of widespread stands of uniform

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1991.tb01479.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractNitrogen mineralization and nitrification were measured usingin situincubations for 12 periods of 1 month in a structurally complex rainforest with basaltic soil, and an adjacent structurally simple rainforest with less fertile soil formed on metamorphic rock. The study was undertaken near Lake Eacham on the Atherton Tableland in northeast Queensland.Cumulative nitrogen mineralization for 1 year did not differ between forests. It amounted to 265 ± 13 μg N g‐1oven dry soil at the upper position (0–7.5 cm) and 122 ± 11 μg N g‐1oven dry soil at the lower position (7.5–15 cm; mean ± s.e. for pooled data). Rates were highest during the wet season but were not strongly correlated with moisture content or temperature.Relative nitrification (cumulative nitrate‐nitrogen production expressed as a percentage of cumulative nitrogen mineralization) at the upper position was significantly higher in the complex than the simple forest (100% c.f. 88%). At the lower position it amounted to 100% for cumulative data in both forests. Nitrate was the dominant form of inorganic nitrogen in the complex forest but in the simple forest nitrate and ammonium were of similar importance.The association between forest physiognomic structure and nutrient status at Lake Eacham represents a more general pattern in rainforests of northeast Queensland and further study is needed to ascertain whether results from this study apply

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1991.tb01480.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractGermination in 35 species from 15 legume genera of southeastern Australia was promoted by a heat treatment which broke the seed coatcaused dormancy. Once the critical temperature was reached, most seeds had their dormancy broken, independent of the duration of heating. Species fell into three classes according to whether their dormancy was broken by a temperature of 40, 60 or 80°C.Highest germination in all species was achieved by heating in the temperature range 80–100°C, although long durations (120 min) at 100°C caused seed death in several species. At 120°C, seeds of most species were killed at all but one minute's duration. A proportion of seeds from 7 species (Acacia myrtifolia, Pultenaea daphnoides, P. incurvata, P. linophylla, P. polifolia, Dillwynia floribundaandSphaerolobium vimineurn) was not killed at 120°C and had their dormancy broken. This proportion varied markedly and resultant germination levels were significantly less than those at 80 and 100°C, except inS. vimineum.Between‐site variations in the 4 species tested (A. myrtifolia, A. suaveolens, A. terminalisandA. ulicifolia) were small. These variations concerned: (i) the minimum temperature required to break seed dormancy in 2 species: 60°C in one population ofA. myrtifoliaandA. suaveolens, and 80°C in the other; and (ii) the intensity of the germination response.Duration of heating was less important than temperature as a determinant of germination. Ordination techniques revealed that results from one duration across temperatures were comparable with data from multiple durations. This has significant applications in studying rare species, where seed may be in short supply.Predicted germination levels after a moderate intensity fire should far exceed those after a low intensity fire. Little germination was predicted for many species after a low intensity fire and for one species,A. elongata, no germination was predicted. The potential role of indicator species in relation to the maintenance of species in a community i

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1991.tb01481.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe study investigated the relationship between home range and food abundance in a population of the southern brown bandicoot.Isoodon obesulus, in Western Australia. Home range areas were estimated seven times between 1986 and 1988 by live‐trapping, spool‐and‐line devices and fluorescent pigment tracking. The abundance of invertebrate food was measured simultaneously by placing pitfall traps within the home ranges of individual animals, and by sampling invertebrates in topsoil and litter. Home range areas tended to be negatively correlated with food abundance, especially in the autumn and winter of 1986 and 1987.The influence of food on home range was investigated further in September 1988 by providing eight individualI. obesuluswith a supplementary food mixture. Contrary to expectation, the added food caused an increase in home range area, home range overlap and displacement, as well as an influx of new individuals to food stations. In contrast, home range parameters in control (non‐fed) individuals changed little during the experiment.The shuffling of home ranges due to feeding suggests that the home range system ofI. obesulusis relatively flexible, with individuals monitoring and exploiting resources in an opportunistic manner. In contrast to previous studies, we found no evidence thatI. obesuluswas territorial. We speculate that individuals may be territorial at low population density if resources are defendable and intruder pressure is low, but occupy overlapping ranges if population density

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1991.tb01482.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractStand morphometry and age structure were analysed for populations of burgan,Kunzea ericoides, which were colonizing pastoral land in the Tidbinbilla Valley, Australian Capital Territory. Three types of stands, (i) closed burgan‐dominated; (ii) open burgan‐dominated; and (iii) mixed burgan and eucalypts, were compared at each of two locations. Burgan ages were determined from growth ring counts cross‐correlated with seasonal rainfall and annual increments inPinus radiata. Burgan stands have developed from windblown seed coming from nearby forest margins and drainage‐lines. The species colonized rural lands in the Tidbinbilla Valley rapidly from the early 1960s, when changes in land use practices occurred which enabled sparse colonists to contribute to rapid population expansion. Colonization was initially slow, but recruitment increased dramatically in the early 1960s in closed and open stands when densities were between 0.01 and 0.03 plants m‐2. These stands did not follow classic secondary succession, as the differences between stands sampled were largely the result of differences in burgan density and floristic composition of the sites at the time of change in land use practices. These differences in turn influenced the phenotypic response of individual plants and the ensuing stand structures. A closed shrub canopy of burgan, together with the species self‐replacement strategies, is likely to prevent other species from entering the closed burgan sites and becoming dominant. Where the objective is to limit the spread of burgan, isolated plants, which act as foci for spread, would be the primary target

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1991.tb01483.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractPoisson regression analyses were used to relate the number of hollow‐bearing trees on 523 sites in the montane ash forests of the Central Highlands of Victoria to a range of environmental variables. Region, logging history, the dominant species of eucalypt, slope angle, topographic position and the age of the stand influenced significantly the number of hollow‐bearing trees. A simple predictive model containing these factors has possible application in geographic information systems and may assist in the assessment of wildlife habitat.The number of multi‐aged stands and living trees with fire scars indicates that some individuals of ‘fire‐sensitive’ montane ash eucalypts appear to survive inten

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1991.tb01484.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractSeveral researchers have attempted to calculate whether depression of nectar resources by Australian honeyeaters is likely to limit their densities. Such calculations can be misleading, however, and do not directly test whether birds depress nectar availability. I monitored changes in nectar availability during the 8–9 months that honeyeaters bred in heathland near Sydney, and caged inflorescences to test whether nectar availability was being depressed by birds.There were pronounced seasonal changes in nectar availability in each of 2 years, and caging substantially increased the amounts of nectar in inflorescences during months when nectar production was low. The effects of caging must have resulted from exclusion of honeyeaters, as: (i) open‐ended cage controls showed that the effects of caging resulted from exclusion of foragers, not from artifacts of caging; (ii) day‐only and night‐only caging showed that nectar was depleted only during the day: and (iii) observations showed that cages did not exclude any diurnal foragers other than honeyeaters. Resident honeyeaters spent more time foraging during months when nectar was scarce, implying that the rates at which they could obtain nectar were affected by changes in nectar availability. It is therefore possible that the depletion of nectar by honeyeaters could have limited their densities. However. I argue that such limitation could only be inferred safely if nectar‐supplementation experiments showed survival and/or reproduction to be limited by nectar ava

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1991.tb01485.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY