Nutrient Concentrations in Foliage of Species Within a New South Wales Sub-Tropical Rainforest

Sub-tropical rainforests in New South Wales are complex, oftenwith more than 30 tree species ha^–1. Estimation of nutrientcontents involves obtaining information on the range of nutrientconcentrations both in different species and in different foreststrata. The foliage from the tree and shrub components of an undisturbedforest were analyzed chemically together with the small treeand shrub component of an area logged two years previously.The site had high nutrient availability. All nutrients analyzed(nitrogen, phosphorus, calcium, magnesium, potassium, manganese,aluminium, sodium, zinc, iron, boron and chloride) varied betweenspecies. Some individuals accumulated high concentrations ofspecific nutrients, but an accumulator of one nutrient was notnecessarily an accumulator of any other. Assessment of nutrient concentrations on the basis of foreststrata showed major differences. Nutrients were accumulatedin higher concentrations on a disturbed site than on an undisturbedsite. This has been discussed in relation to nutrient conservationmechanisms after disturbance. Within the undisturbed stand,the large shrub stratum had the highest concentrations of nitrogen,phosphorus, potassium and boron. Mean concentrations of aluminium,sodium and chloride were highest in the small shrub stratum,mainly because several species accumulate these elements. Sub-tropical rainforest, nitrogen, phosphorus, calcium, magnesium, potassium, manganese, aluminium, sodium, zinc, iron, boron, chloride     

Molecular sexing of the communally breeding pukeko: an important ecological tool

A central biological parameter in the study of any animal population is the accurate assignment of sex. Indeed any ecological study of a population requires information on sex composition in relation to such biological factors as behaviour, movement, mortality and birth rate. However, our ability to assign the sex of adults of many avian species is poor and the sexing of young is universally difficult. We report here the successful application of a molecular technique for the assignment of sex in the communally breeding pukeko or purple swamphen ( Porphyrio porphyrio melanotus ). W- and Z-linked chromosome fragments in digested genomic DNA of pukeko were detected with the DNA probe pMg1. We consequently show that this species breeds in polyandrous, polygynous and polygynandrous groups. Finally we discuss why recent molecular methods represent important new tools in ecology.     

Phylogenetic profiles: a graphical method for detecting genetic recombinations in homologous sequences

Phylogenetic profiles constitute a novel way of graphically displaying the coherence of the sequence relationships over the entire length of a set of aligned homologous sequences. Using a sliding-window technique, this method determines the pairwise distances of all sequences in the windows and evaluates, for each sequence, the degree to which the patterns of distances in these regions agree. This method is suited for exploring data consistency as well as detecting recombinant sequences. A computer program implementing the algorithm has been developed, and examples with simulated and natural sequences are given to demonstrate the sensitivity and accuracy of the method for identifying recombinant sequences and their recombination junctions as well as detecting hot spots of recombinational activity.