The three southern conifer families, Araucariaceae, Cupressaceae and Podocarpaceae, have a long history and continue to be an important part of the vegetation today. The Araucariaceae have the most extensive fossil record, occurring in both hemispheres, and with Araucaria in particular having an ancient origin. In the Southern Hemisphere Araucaria and Agathis have substantial macrofossil records, especially in Australasia, and Wollemia probably also has an important macrofossil record. At least one extinct genus of Araucariaceae is present as a macrofossil during the Cenozoic. Cupressaceae macrofossils are difficult to identify in older sediments, but the southern genera begin their record in the Cretaceous (Athrotaxis) and become more diverse and extensive during the Cenozoic. Several extinct genera of Cupressaceae also occur in Cretaceous and Cenozoic sediments in Australasia. The Podocarpaceae probably begin their macrofossil record in the Triassic, although the early history is still uncertain. Occasional Podocarpaceae macrofossils have been recorded in the Northern Hemisphere, but they are essentially a southern family. The Cenozoic macrofossil record of the Podocarpaceae is extensive, especially in south-eastern Australia, where the majority of the extant genera have been recorded. Some extinct genera have also been reported from across high southern latitudes, confirming an extremely diverse and widespread suite of Podocarpaceae during the Cenozoic in the region. In the Southern Hemisphere today conifers achieve greatest abundance in wet forests. Those which compete successfully with broad-leaved angiosperms in warmer forests produce broad, flat photosynthetic shoots. In the Araucariaceae this is achieved by the planation of multiveined leaves into large compound shoots. In the other two families leaves are now limited to a single vein (except Nageia), and to overcome this limitation many genera have resorted to re-orientation of leaves and two-dimensional flattening of shoots. The Podocarpaceae show greatest development of this strategy with 11 of 19 genera producing shoots analogous to compound leaves. The concentration of conifers in wet forest left them vulnerable to the climate change which occurred in the Cenozoic, and decreases in diversity have occurred since the Paleogene in all regions where fossil records are available. Information about the history of the dry forest conifers is extremely limited because of a lack of fossilisation in such environments. The southern conifers, past and present, demonstrate an ability to compete effectively with angiosperms in many habitats and should not be viewed as remnants which are ineffectual against angiosperm competitors.

Vulnerability of stem xylem to cavitation was measured in 10 species of conifers using high pressure air to induce xylem embolism. Mean values of air pressure required to induce a 50% loss in hydraulic conductivity (ϕ50) varied enormously between species, ranging from a maximum of 14.2±0.6 MPa (corresponding to a xylem water potential of −14.2 MPa) in the semi‐arid species Actinostrobus acuminatus to a minimum of 2.3±0.2 MPa in the rainforest species Dacrycarpus dacrydioides. Mean ϕ50 was significantly correlated with the mean rainfall of the driest quarter within the distribution of each species. The value of ϕ50 was also compared with leaf drought tolerance data for these species in order to determine whether xylem dysfunction during drought dictated drought response at the leaf level. Previous data describing the maximum depletion of internal CO2 concentration (ci) in the leaves of these species during artificial drought was strongly correlated with ϕ50 suggesting a primary role of xylem in effecting leaf drought response. The possibility of a trade‐off between xylem conductivity and xylem vulnerability was tested in a sub‐sample of four species, but no evidence of an inverse relationship between ϕ50 and either stem‐area specific (Ka) or leaf‐area specific conductivity (K1) was found.

Australia is an ancient continent with an interesting geological history that includes a recent major shift in its position, both globally and compared with neighbouring land masses. This has led to a great deal of confusion over many years about the origins of the Australian biomes. The plant fossil record is now clarifying this, and it is clear that the ancient Gondwanan rainforests that covered Australia while it was still part of that supercontinent contained many of the elements of the modern vegetation. However, major climatic sifting, along with responses to other factors, including soil nutrient levels, disturbance regimes, atmospheric CO 2 levels, fire frequency and intensity, glaciations and the arrival of humans, have had profound impacts on the Australian vegetation, which today reflects the sum of all these factors and more. The origins of Australian vegetation and its present-day management cannot be properly understood without an appreciation of this vast history, and the fossil record has a vital role to play in maintaining the health of this continent's vegetation into the future.

Currently, slightly less than half the world's population lives in dense urban areas, principally cities. In Australia, nearly 85% of people live in towns with 1000 or more residents. Although individual species of urban flora and fauna have often been well studied, little is known of the long‐term temporal patterns associated with changes in both the abiotic and biotic environments as urban systems expand. Using historical and current information, the changes in species richness (defined as the native and introduced vertebrates and vascular plants) in Adelaide, South Australia, are described from its founding in 1836 until 2002. Adelaide is an isolated city of over a million inhabitants, bordered by a range of hills and the South Australian coastline. With a Mediterranean climate, a culture that places high importance on private residential gardens, and the presence of extensive public parklands, the metropolitan area has a significant diversity of both native and introduced flora and fauna. Using only the presence or absence of a species, the changes to plant and vertebrate species richness were quantified by analyzing the observed patterns of change at a functional group level. Powerful correlative evidence is provided to explain the development and establishment of patterns in urban ecology. There has been a dramatic change in species composition, with an increase in total species numbers of ∼30%. At least 132 native species of plants and animals have become locally extinct, and a minimum of 648 introduced species have arrived (mostly plants). The plants increased in species richness by 46%. Fifty percent of the native mammal species were lost, and overall, the birds declined by one species, representing 21 extinctions and 20 successful introductions. Amphibians and reptiles showed no net change. The herbaceous perennial and annual plant species richness showed a substantial increase. This temporal approach to urban ecology demonstrates new ways to identify individual species or groups at risk of extinction and provides some long‐term management goals for large urban areas.