Aim Stratification of major differences in the biophysical features of landscapes at the continental scale is necessary to collectively assess local observations of landscape response to management actions for consistency and difference. Such a stratification is an important step in the development of generalizations concerning how landscapes respond to different management regimes. As part of the development of a comparative framework for this purpose, we propose a climate classification adapted from an existing broad scale global agro-climatic classification, which is closely aligned with natural vegetation formations and common land uses across Australia. LocationThe project considered landscapes across the continent of Australia. MethodsThe global agro-climatic classification was adapted by using elevationdependent thin plate smoothing splines to clarify the spatial extents of the 18 global classes found in Australia. The clarified class boundaries were interpolated from known classes at 822 points across Australia. These classes were then aligned with the existing bioregional classification, Interim Biogeographic Regionalization for Australia IBRA 5.1. ResultsThe aligned climate classes reflect major patterns in plant growth temperature and moisture indices and seasonality. These in turn reflect broad differences in cropping and other land use characteristics. Fifty-two of the 85 bioregions were classified entirely into one of the 18 agro-climatic classes. The remaining bioregions were classified according to sub-bioregional boundaries. A small number of these sub-bioregions were split to better reflect agro-climatic boundaries. Main conclusionsThe agro-climatic classification provided an explicit global context for the analysis. The topographic dependence of the revised climate class boundaries clarified the spatial extents of poorly sampled highland classes and facilitated the alignment of these classes with the bioregional classification. This also made the classification amenable to explicit application. The bioregional and subregional boundaries reflect discontinuities in biophysical features. These permit the integrated classification to reflect major potential differences in landscape function and response to management. The refined agro-climatic classification and its integration with the IBRA bioregions are both available for general use and assessment.
I vllL@l!y UL L U~I~G~V~L~U I IZommission of the Northern Territory, Alice Springs, NT 0871. AbstractWe developed two sets of regression models for flowering and fruiting of arid zone trees and shrubs, based on (i) rainfall in the current and preceding seasons and (ii) soil moisture lagged over varying time periods combined with mean maximum temperature and daylength in the month prior to phenological observations. Using up to 4 years of flowering and fruiting records, we found that both approaches identified responses matching those reported in two other long-term data sets or in the literature, for some species but not for all. The second approach appeared to provide better correlations than the first but we were unable to predict flowering and fruiting effectively.Flowering and fruiting of central Australian trees and shrubs were least in late summer, creating potential limitations on animal populations dependent on them for food. With better predictive capabilities, there is some scope for managing the trees and shrubs for particular purposes. However, very long-term phenological records are needed to improve predictions.
The need to predict potential invasion impact of plant species is important for setting weed-management priorities and determining quarantine restrictions for newly imported plant material. We analysed the naturalised plant component of a herbaceous plant community in sub-tropical eucalypt woodlands subjected to various disturbances associated with agricultural activities. The native and naturalised plant species did not differ in the proportions of different life forms, although life-history differed, with the naturalised group having more annual and biennial, and relatively fewer perennial species. We classified the naturalised assemblage into high- and low-impact species and compared the plant-trait and habitat characteristics of the two groups. Low-impact species covered a range of levels of habitat specialisation whereas high-impact species tended to have moderate to low levels of specialisation and to be less tolerant of grazing. Seven traits were found to be significantly associated with impact. Stepwise regression indicated a high level of redundancy in the data, owing to attributes being correlated. For all species, four attributes were significant in determining impact: very wide lateral spread, C4 photosynthesis, tall height and large leaves. For forbs, only two attributes (large seeds, adhesion/ingestion mode of seed dispersal) were significant in the overall model. We identified the following eight functional types amongst the naturalised species: (i) high-impact C4 lawn grasses, (ii) high-impact C4 bulky tussock grasses, (iii) moderate-impact annual grasses, (iv) moderate-impact tall annual forbs, (v) moderate-impact spreading forbs, (vi) moderate-impact woody forbs, (vii) low-impact legumes and (viii) low-impact small ruderals. In the subtropical woodland environment perennial C4 grasses appear to present the greatest invasive threat to herbaceous native communities, whereas forbs of wide lateral spread, with large animal-dispersed seeds are also problematic. The results support a case for limiting further importation of horticultural and forage material into Australia.
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