Major progress in understanding biological invasions has recently been made by quantitativelycomparing successful and unsuccessful invasions. We used such an approach to test hypotheses about the role of climatic suitability, life history, and historical factors in the establishment and subsequent spread of 40 species of mammal that have been introduced to mainland Australia. Relative to failed species, the 23 species that became established had a greater area of climatically suitable habitat available in Australia, had previously become established elsewhere, had a larger overseas range, and were introduced more times. These relationships held after phylogeny was controlled for, but successful species were also significantly more likely to be nonmigratory. A forward-selection model included only two of the nine variables for which we had data for all species: climatic suitability and introduction effort. When the model was adjusted for phylogeny, those same two variables were included, along with previous establishment success. Of the established species, those with a larger geographic range size in Australia had a greater area of climatically suitable habitat, had traits associated with a faster population growth rate (small body size, shorter life span, lower weaning age, more offspring per year), were nonherbivorous, and had a larger overseas range size. When the model was adjusted for phylogeny, the importance of climatic suitability and the life-history traits remained significant, but overseas range size was no longer important and species with greater introduction effort had a larger geographic range size. Two variables explained variation in geographic range size in a forward-selection model: species with smaller body mass and greater longevity tended to have larger range sizes in Australia. These results mirror those from a recent analysis of exotic-bird introductions into Australia, suggesting that, at least among vertebrate taxa, similar factors predict establishment and spread. Our approach and results are being used to assess the risks of exotic vertebrates becoming established and spreading in Australia. Resumen:Recientemente se ha logrado un progreso importante en el entendimiento de invasiones biológicas al comparar invasiones exitosas y no exitosas cuantitativamente. Utilizamos ese método para probar hipótesis acerca de la adaptabilidad climática, historia de vida y factores históricos en el establecimiento y extensión posterior de 40 especies de mamíferos que han sido introducidas en Australia. En relación con especies no exitosas, las 23 especies que se establecieron tenían una mayorárea de hábitat adecuado climáticamente en Australia, se habían establecido en otras partes, tenían un mayor rango y fueron introducidas más veces. Después de controlar para filogenia, estas relaciones se mantuvieron, pero las especies exitosas también fueron significativamente no migratorias. Un modelo de selección anterior incluyó a sólo dos de las nueve variables 558 Establishment and Spread of Exotic MammalsFor...

Field experiments were carried out at seven sites in southern Australia from 2002 to 2006 to measure changes in plant frequency, root characteristics and summer activity for a range of grass and herb species or cultivars. Annual rainfall during the experimental period was on average 75 mm lower than the long-term average. Plant frequency differed significantly between species and between sites. Temperate grasses generally had higher frequencies than subtropical grasses, native grasses and herbs. Cocksfoot (Dactylis glomerata cvv. Currie, Porto), tall wheat grass (Thinopyrum ponticum cv. Dundas), winter-active tall fescue (Festuca arundinacea cvv. Fraydo, Resolute MaxP) and phalaris (Phalaris aquatica cvv. Atlas PG, Australian) were the most persistent of the temperate perennial species over the experimental period. The frequency of most cultivars declined from year 2 to year 4 after establishment, but the frequency of kikuyu (Pennisetum clandestinum cv.Whittet) and wallaby grass (Austrodanthonia richardsonii cv. Taranna) increased by over 5% from year 2 to year 3, and cocksfoot (cv. Currie) increased from year 3 to year 4. At two sites where measurements were made, there were significant differences in rooting depth between species. Whittet kikuyu was the deepest among all species with a rooting depth of up to 2 m, followed by phalaris, tall fescue, grazing brome (Bromus stamineus) and tall wheat grass. Root density was affected by plant genotype and soil structure. Root density of the species varied significantly in the subsoil (0.1–1.1 m) and deeper subsoil (1.1–2 m) but not in the topsoil (0–0.1 m). Green-leafiness over summer was generally higher for subtropical grasses, native grasses, herbs and some summer-active temperate grasses, than most temperate grasses with high summer dormancy.

Deep-rooted perennial pasture plants can play an important role in solving the environmental problems of rising watertables, dryland salinity and soil acidification in the wheatbelt of southern Australia. These problems are attributed to the extensive clearing of perennial native vegetation and its replacement with shallow-rooted winter-growing annual crops and pastures. Deep-rooted, herbaceous perennial legumes, particularly lucerne (Medicago sativa L.), are seen as making an increasing contribution in the cropping zones where high rates of symbiotic nitrogen fixation and increased water use are high priorities. This paper reviews the current use and the potential of a range of temperate perennial legumes for the wheatbelt of southern Australia. The genera examined include Medicago, Hedysarum, Trifolium, Onobrychis, Lotus, Galega, Astragalus, Lathyrus, Anthyllis, Psoralea, Dorycnium, Lespedeza and Securigera. There is considerable scope to expand the use of lucerne; however, there is also a need for alternative perennial species to increase biodiversity and to fill niches where lucerne is less suited. Based on current knowledge, the species with the most promise to complement lucerne include sainfoin (Onobrychis viciifolia Scop.) and sulla (Hedysarum coronarium L.) on alkaline soils, strawberry clover (Trifolium fragiferum L.) in wet or mildly saline niches and Lotus and Dorycnium spp. on waterlogged and/or acid soils.

Ninety-one perennial legumes and herbs (entries) from 47 species in 21 genera were evaluated at sites in New South Wales, South Australia and Western Australia over 3 years from 2002 to 2005 to identify plants with superior herbage production, persistence and the potential to reduce ground water recharge. Evaluation was undertaken in three nurseries (general, waterlogged soil and acid soil). Medicago sativa L. subsp. sativa (lucerne) cv. Sceptre was the best performing species across all sites. In the general and acid soil nurseries, Cichorium intybus L. (chicory) cv. Grasslands Puna was the only species comparable with Sceptre lucerne in terms of persistence and herbage production. Trifolium fragiferum L. cv. Palestine and Lotus corniculatus L. SA833 were the best performing species on heavy clay soils prone to waterlogging. Three Dorycnium hirsutum (L.) Ser. accessions persisted well on acid soils, but were slow to establish. Short-lived perennial forage legumes, such as Onobrychis viciifolia Scop. cv. Othello, and three Hedysarum coronarium L. entries, including cv. Grasslands Aokou, had high herbage production in the first 2 years and may be suitable for short-term pastures in phased pasture-crop farming systems. T. uniflorum L. and M. sativa subsp. caerulea SA38052 were highly persistent and could play a role as companion species in mixtures or ground cover species for undulating landscapes. Cullen australasicum (Schltdl.) G.W. Grimes SA4966 and Lotononis bainesii Baker cv. Miles had poor establishment, but were persistent. Chicory, T. fragiferum and L. corniculatus were identified as species, other than lucerne, with the most immediate potential for further selection to increase the diversity of perennial legumes and herbs adapted to southern Australian environments.