Noel D. Preece

Traditional and ecological fires and effects of bushfire laws in north Australian savannas

Landscape fires are common and frequent across the north Australian savannas, and are arguably an essential component of regional ecosystem dynamics. Seasonal biases in fire regimes and the high frequency of late dry season fires in a large proportion of the region have been presented as an impediment to appropriate land management. Legislation regulating the lighting of fires applies to the whole of the savannas. The legislation seeks to control the lighting of fires, provides for permit systems to operate in each jurisdiction, and is supported by policies and guidance manuals. The present paper argues that the legislation fails to address prescribed burning, the biophysical and social realities of contemporary regimes, and management needs. The policies and legislation are in need of some fundamental changes, including recognition of the concept of prescribed burning, mechanisms to promote regional fire management strategies and plans, and recognition of indigenous traditional practices.

Use by small mammals of a chronosequence of tropical rainforest revegetation

Abstract Context. The conversion of tropical rainforest to grazing pasture results in a drastic change in small-mammal community composition. Restoring the landscape through ecological revegetation is thus an increasingly important management technique to conserve rainforest mammals. Aims. This study aimed to determine the habitat ages at which species of small mammals recolonised revegetated habitats on the southern Atherton Tablelands, north-eastern Queensland, Australia. We focussed on changes in rainforest mammal abundance and diversity with increasing habitat age. Methods. Small-mammal trapping and mark–recapture techniques investigated mammal diversity, abundance and community composition within remnant rainforest, three age classes of ecological revegetation and abandoned grazing pasture. Key results. Small-mammal community composition differed between remnant rainforest and abandoned grazing pasture. The pasture and 3-year old revegetated sites were similar in composition, both lacking rainforest small mammals. Six- and 7-year old revegetation plantings provided suboptimal habitat for both rainforest and grassland mammals, whereas 16- and 22-year old revegetated habitats were dominated by rainforest species, with some individuals being frequently recaptured. Conclusions. As revegetated habitats aged, the small-mammal community composition transitioned from a grassland-like composition to a community dominated by rainforest species. Implications. Although rainforest small mammals were very occasionally captured within the 6- and 7-year old habitats, revegetated plantings were not dominated by rainforest species until the habitat was 16 years old. This highlights the importance of commencing revegetation as early as possible to minimise future population declines and maximise the conservation of rainforest mammals.

Ants as ecological indicators of rainforest restoration: Community convergence and the development of an Ant Forest Indicator Index in the Australian wet tropics

Abstract Ecosystem restoration can help reverse biodiversity loss, but whether faunal communities of forests undergoing restoration converge with those of primary forest over time remains contentious. There is a need to develop faunal indicators of restoration success that more comprehensively reflect changes in biodiversity and ecosystem function. Ants are an ecologically dominant faunal group and are widely advocated as ecological indicators. We examine ant species and functional group responses on a chronosequence of rainforest restoration in northern Australia, and develop a novel method for selecting and using indicator species. Four sampling techniques were used to survey ants at 48 sites, from grassland, through various ages (1–24 years) of restoration plantings, to mature forest. From principal components analysis of seven vegetation metrics, we derived a Forest Development Index (FDI) of vegetation change along the chronosequence. A novel Ant Forest Indicator Index (AFII), based on the occurrences of ten key indicator species associated with either grassland or mature forest, was used to assess ant community change with forest restoration. Grasslands and mature forests supported compositionally distinct ant communities at both species and functional levels. The AFII was strongly correlated with forest development (FDI). At forest restoration sites older than 5–10 years that had a relatively closed canopy, ant communities converged on those of mature rainforest, indicating a promising restoration trajectory for fauna as well as plants. Our findings reinforce the utility of ants as ecological indicators and emphasize the importance of restoration methods that achieve rapid closed‐canopy conditions. The novel AFII assessed restoration status from diverse and patchily distributed species, closely tracking ant community succession using comprehensive species‐level data. It has wide applicability for assessing forest restoration in a way that is relatively independent of sampling methodology and intensity, and without a need for new comparative data from reference sites.

The role of topography and plant functional traits in determining tropical reforestation success

1. Early establishment and sapling growth is a key phase in ensuring cost-effective reforestation success in relation to biodiversity outcomes. Therefore species selection must consider the interaction between plant functional traits and the often-challenging and heterogeneous biophysical environment of degraded landscapes. 2. In this study, we examine how microtopography (slope) results in spatial heterogeneity of soil nutrients, especially phosphorus (P) in a degraded tropical pasture landscape in Queensland, Australia. We then explore how this small-scale heterogeneity influences the growth of two native tree species, Cardwellia (C.) sublimis (Proteaceae) and Flindersia (F.) brayleyana (Rutaceae), which differ in key nutrient-acquisition strategies. 3. The proteaceous C. sublimis was found to be buffered from possible P limitation in degraded soils due to its effective P acquisition by cluster roots. In contrast to C. sublimis, which showed no difference in growth after 5 years across a range of soil conditions, F. brayleyana was found to be highly responsive to soil conditions with increased growth in low-slope, higher P availability areas. The ability of F. brayleyana to take advantage of high soil P levels, including the development of leaves with higher P concentrations, resulted in an apparent switch in competitive fitness between these two species across a landscape gradient. 4. Synthesis and applications. In a detailed study of a landscape reforestation experiment in North Queensland, Australia, we demonstrate that site edaphic factors can vary within tens of meters due to topographic relief, and that species respond differently to these conditions. We therefore show the need to consider both the spatial heterogeneity of edaphic factors and the below ground functional traits of potential reforestation species when planning reforestation programs.

Modelling Weed Distribution Across the Northern Australia Using Very Extensive Transects

A Generalised Additive Modelling (GAM) approach is used to predict weed occurrence across the Top End of the Northern Territory, Australia. The availability of new toolsets such as GRASP (Generalised Regression Analysis and Spatial Predictions) and the application of novel GIS variables, including remotely sensed Radiometric data, Infrastructure density (roads and fences) mapping and Climate layers, provide a useful framework for mapping regions at high risk of infestation. An independent set of weed locations provides support for the regional accuracy of the modelling. Infrastructure density is a significant factor in the prediction of weed occurrence in this study. Coastal areas with high levels of infrastructure appear most susceptible to weed infestation, although 8 Biogeographic Regions are considered currently at risk.