The impact of the 1986-87 El Nido-Southern Oscillation (ENSO) event on seabirds in the Galapagos Islands was generally less severe than that of the previous ENSO in 1982-83. Sea surface temperatures (SST) rose to levels comparable to those of 4 ENSOs pnor to the 1982-83 event. SST became anomalous approximately in January and had returned to typical levels by July. Blue-footed booby Sula nebouxii reproductive attempts failed throughout the archipelago, and breeding colonies were deserted, shortly after SST became unusually warm in January. Masked boobies S. dactylatra, redfooted boobies S. sula and several other species were apparently unaffected by the anomalous conditions, or temporarily suspended breeding for several months. A gradient in both SST and in the ENSO's impact on some seabirds was evident, with populations nesting in the cooler south of the archipelago affected less than those in the warmer north. At one colony studied both before and during the ENSO, blue-footed booby failure was associated with apparent reductions in both availablllty and body size of their primary prey item.

Traditional tabular sorting practices emphasize the differential importance of species within stand groups. Such a method orders (ordinates) the species while classi- fying stands, and by symmetry an inverse analysis will ordinate stands while classifying species. In this paper some methods of defining group structure which permit choice at any division between normal and inverse approaches are examined. One of these, the two-parameter method, also permits monotonic variation within groups, and in this case the choice of normal or inverse analysis is equivalent to a choice of classi- fication or ordination alternatives. Such an analysis is termed inosculate. In comparison with a quantitative information analysis, the two-parameter method provides a more detailed and informative representation, although the division procedure is monothetic. The establishment of dominance, constancy, and fidelity criteria is examined, and the environmental interpretation of species and stand groups attempted. While the analysis is computationally time-consuming for quantitative data, it is certainly very rewarding. Some alternative approaches permitting inosculate analysis are also briefly examined.

The application of multiple pattern analysis (multiscale ordination) to a phase-differentiated sample of perennial saltbush (Atriplex vesicaria) rangeland, along with assessments of the vegetative and reproductive states of individual plants, served to indicate the importance of sheep in determining some scales of distributional pattern in the shrub population. By comparison with conventional pattern analysis, it is shown that multiple pattern analysis can be used to provide an economic description of 'total' pattern in temporally related phases of a monospecific plant population. It is demonstrated that the pattern-determining interaction between sheep and saltbush individuals is dependent on plant size, sex and location with respect of other shrub individuals, in particular due to the trampling of seedling and pioneer phases and the selective grazing of sexually mature shrubs by sheep.

The majority of pattern analyses of total density data collected from geographically separated populations of Atriplex vesicaria, both in the western Riverine Plain of New South Wales and in areas of north-western New South Wales, provided evidence of bi- or trimodal contagion. More detailed analyses of pattern in age-related phases of these populations exhibited most intense patterning in 'seedling' phases, with a progressive reduction of pattern intensity in subsequent ('pioneer', 'building' and 'mature') phases of the entire population. It has been found that the pattern of young individuals may be correlated with patterned variation in microtopography, as well as with water and nutrient availability, and that the indirect effects of grazing animals may be responsible for the intermediate scales of the mosaic pattern in populations of sexually mature individuals. The performance of A. vesicaria plants was assessed experimentally in relation to a range of natural soils, with associated watering and defoliation treatments, and in controlled nutrient solution culture. The results suggest that performance (as estimated by dry weight yield) is affected significantly by soil type, water stress and defoliation. In an experimental context the prime effect of soil variation on yield appeared to be mediated by variation in soil cation balance, a patterned balance that may have been historically induced in the field situation.

Multivariate analyses of vegetation data are normally restricted to a single scale of sampling, but since the pattern of species populations may vary over a range of scales, restriction to a single scale can result in a loss of potentially useful information. It is possible to examine spatial variation for a single species or pairs of species by block size variance (or covariance) analysis, but this is a somewhat cumbersome procedure when more than a few species are involved. A method which combines block size variance analysis with a multivariate (principal components) analysis is described and applied to a woodland community in south central Queensland. Contiguous site data, recorded as density scores for all tree and shrub species along a transect 512 m by 20 m, were grouped into successively larger blocks. Variance covariance matrices at each block size were calculated and added to form a combined covariance matrix. This was subjected to a principal components analysis to obtain species and sites coordinates. Each characteristic root was subsequently partitioned into contributions from the various block sizes, and the partitioned roots plotted against block size as in conventional pattern analysis. The first two components represented macro-variation in the vegetation of the transect (at scales of 120-250 m) and separated three macrocommunities which were associated with soil types. Two subsequent components expressed compositional differences at smaller scales (30-60 m) within these macrocommunities.