摘要:

AbstractBirds and environments of tropical rainforests were studied in 18 selected areas from sea level to 1520 m within the humid tropical region of northeastern Australia. A total of 122 sites (20 m × 20 m each) were established within the 18 areas, and bird data (observation and mist‐netting) and environmental data (pro formasurvey and foliage measurements) were collected at each site. The bird data were analysed numerically in two ways: abundance of 146 species in 18 areas and presence and absence of 108 species at 122 sites. Both classification and ordination analyses produced a major discontinuity between the tableland sites and the lowland sites, each divisible further into various types of vine forest and non‐vine forest vegetation. The few rare species did not contribute to the general pattern. The environmental data were reduced to a set of those attributes that showed variation among the sites. They included topographic and edaphic features, physiognomic and structural features of vegetation, fruiting and defoliating habits of plants, foliage height diversity and evenness, and canopy cover. The primary pattern in the data set of 135 attributes by 122 sites was vine forest versus nonvine forest, and altitudinal divisions appeared as a secondary pattern, in both classification and ordination.Canonical correlation coefficients between bird vectors and environmental vectors were reasonably high for the first four canonical vectors, which correlated well with major Gower vectors of birds and environments. The back‐correlation to the raw data produced bird species and matching environmental attributes with sites sharing them for both positive and negative ends of each canonical vector. In general, the analysis extracted elements of both fauna and environment that characterized the vine forest as opposed to the non‐vine forest and the tableland sites as opposed to the lowland sites. Canonical correlation analysis is limited by the unverifiable nature of derived correlations. Such correlations may suggest certain associations to be tested by independent means (hypothesis‐generating function), but may also formalize self‐evident or fortuitous

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1982.tb01308.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractEvidence is presented which indicates that the removable wax layer on juvenile leaves of several species of Encalyptus provides protection from grazing by the Eucalyptus tortoise beetle,Paropsis charybdis, by preventing the adult beetles from gaining a foothold. Other possible roles of Eucalyptus leaf waxes, particuarly those related to frost resistance, are considered in the light of the present observations.

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1982.tb01309.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractMonthly sweep net and light trap samples were used to examine seasonal changes in the abundance of insects in subtropical, warm and cool temperate rain forest in New South Wales. Maximum insect abundance, especially of phytophages, coincided with leaf flushing in the canopy trees. Cool temperate insect numbers were highest during the month just following the beech leaf flush, a rapid and synchronous growth event. Conversely, numbers of subtropical insects fluctuated over a longer period, in a pattern similar to the continuous growth of leaves that occurred throughout spring and summer there. The warm temperate was intermediate in its vegetation growth phenology and insect patterns. Rainforest insect abundance varied both temporally and spatially.

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1982.tb01310.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractPlant biomass, net primary productivity and dry matter turnover were studied in a grassland situated in a tropical monsoonal climate at Kurukshetra, India (29°58′N, 76°51′E). Based on differences in vegetation in response to microrelief, three stands were distinguished on the study site. The stand I was dominated bySesbania bispinosa, stand II represented mixed grasses and stand III was dominated byDesmostachya bipinnata.Floristic composition of the three stands revealed the greatest number of species on stand II (75). The study of life form classes indicated a thero‐cryptophytic flora. The biomass of live shoots in all the three stands attained a maximum value in September (424–1921 g m‐2) and below ground plant biomass in November (749–1868 g m‐2). The annual above ground net primary production was greatest on stand I (2143 g m‐2) and lowest on stand II (617 g m‐2). The rate of production was highest during the rainy season (15.34 to 3.18 g m‐2day‐2). Below ground net production ranged from 1592 to 785 g m‐2y‐2and the rates were high in winter and summer seasons. Total annual net primary production was estimated to be 3141, 1403, 2493 and 2134 g m‐2on stands I, II, III and on the grassland as a whole, respectively. The turnover of total plant biomass plus below ground biomass indicated almost a complete replacement of phytomass within the year. The system transfer functions showed greater transfer of material from total net primary production to the shoot compartment during rainy season and to the root compartment dur

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1982.tb01311.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractOne hundred and seven sample plots were established on a study area at Jabiluka, Northern Territory, and detailed quantitative floristic and structural data were collected. Data collection was by sampling both on aerial photographs and in the field, and both sets of data were used to describe the primary floristic types and structural sub‐types. Cluster analysis (Orloci 1967, 1969), polar ordination (Mathews 1977) and Specht's (1970, 1977) approach to vegetation classification were used to analyse the data. Two independent clustering techniques, one based on art information measure and the other on a measure of within group dispersion, produced very similar dendrograms. The analyses consistently separated the plots into three major groups ‐ floodplain, dryland and sandstone landscapes; within these groups 15 floristic associations and eight structural formations were identified. The environmental parameters associated with the various groups were substrate type, and seasonal inundation from the Magela Creek system. The results of ordination did not highlight any environmental parameters not already made evident by cluster analy

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1982.tb01312.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA simple method for decomposing a population's stage grouping into the underlying age structure is described. The population's dynamics can then be predicted using standard age‐structured models, such as Leslie's matrix model. The method overcomes objections to previous attempts to use Leslie's procedure for modelling population growth in stage‐grouped organisms. A hypothetical example is used to illustrate the new techni

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1982.tb01313.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA portable gas chromatograph was employed in the Vestfold Hills, Antarctica, during the austral summer of 1979‐80 for determining nitrogenase activity of the blue‐green alga Nostoc commune Vaucher by the acetylene reduction assay. Acetylene reduction was measured in samples taken along a transect where the vegetation changed with respect to differing topography and water availability. Submerged colonies of Nostoc recorded the highest fixation rates (6.89 nmol C2H4. cm‐2h‐1). Damp mosscyanophyte associations growing on shallow slopes showed moderate rates of acetylene reduction (1.99 nmol C2H4. cm‐2h‐1) whilst the drier vegetation of the steeper terrain was the least active (0.19 nmol C2H4. cm‐2h‐1. The employment of a high sensitivity portable gas chromatograph provided an accurate and reliable method of measuring acet

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1982.tb01314.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA device for measuring the integrated temperature sensed by a thermocouple during a grass, forest or other landscape fire is described and its performance evaluated. It consists of a small tube containing an electronic circuit to which is attached a length of thermocouple wire. The tube is buried for the duration of the fire. Principal component of the circuit is an E‐cell (or microcoulometer) which when cleared allows calculation of the temperature/time integral. Performance was found to be reliable and accurate: because of its low cost it has widespread application for measuring the temperature in soil, plants or air during fire

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1982.tb01315.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractIn this paper the role of pattern analytic methods is examined. Recently Harrington et al. (1981) have argued that such methods provide no information which is not already available to the user and that they therefore must be considered useless. It is first suggested that Harrison et al. provided no proof that the information obtained from a pattern analysis was already known to them. It is further suggested that they have misunderstood the role of pattern analysis in the identification of processes for generation of variation in vegetation, restricting it solely to certain mathematical techniques of search. However the assignment of credit or debit to the various components of an analysis, where these include such things as choice of sample units, selection of descriptors, identification of appropriate accuracy and precision for measurement as well as the selection of similarity measures and structuring techniques, remains a very difficult task. Harrington et al. do not appear from their paper to have thoroughly explored all possibilities. In fact the results obtained by them reflect the complexity of the ecological situation. Thus the difficulty they had in interpretation reflects their desire for a simplistic solution. Whether changes in all features of the analysis can provide such a simple result is not known. However it can hardly be considered the fault of the analysis if no such simplicity exists.

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1982.tb01316.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThere are two distinct plant assemblages on the dunecrests of the Simpson Desert. The first is characterized byZygochloa paradoxaandChamaesyce wheeled.The second is marked by the presence ofCalotis erinaceaandHelichrysum ambiguum.There are no consistent differences in texture or fertility between the soils occupied by these four species on the sandridges though there are some differences in other habitats. Hence static soil differences cannot account for the distribution of the two assemblages. It is suggested that the Calotis patches represent populations spread from focal plants established after the 1960s drought, but this remains untested.

ISSN:0307-692X    

DOI:10.1111/j.1442-9993.1982.tb01317.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY