Aim This paper reviews the biogeography of the Australian monsoon tropical
biome to highlight general patterns in the distribution of a range of organisms
and their environmental correlates and evolutionary history, as well as to identify
knowledge gaps.
Location Northern Australia, Australian Monsoon Tropics (AMT). The AMT
is defined by areas that receive more than 85% of rainfall between November
and April.
Methods Literature is summarized, including the origin of the monsoon
climate, present-day environment, biota and habitat types, and phylogenetic and
geographical relationships of selected organisms.
Results Some species are widespread throughout the AMT while others are
narrow-range endemics. Such contrasting distributions correspond to presentday
climates, hydrologies (particularly floodplains), geological features (such as
sandstone plateaux), fire regimes, and vegetation types (ranging from rain forest
to savanna). Biogeographical and phylogenetic studies of terrestrial plants
(e.g. eucalypts) and animals (vertebrates and invertebrates) suggest that distinct
bioregions within the AMT reflect the aggregated effects of landscape and
environmental history, although more research is required to determine and
refine the boundaries of biogeographical zones within the AMT. Phylogenetic
analyses of aquatic organisms (fishes and prawns) suggest histories of associations
with drainage systems, dispersal barriers, links to New Guinea, and the existence
of Lake Carpentaria, now submerged by the Gulf of Carpentaria. Complex
adaptations to the landscape and climate in the AMT are illustrated by a number
of species.
Main conclusions The Australian monsoon is a component of a single global
climate system, characterized by a dominant equator-spanning Hadley cell.
Evidence of hot, seasonally moist climates dates back to the Late Eocene, implying
that certain endemic elements of the AMT biota have a long history. Vicariant
differentiation is inferred to have separated the Kimberley and Arnhem Land
bioregions from Cape York Peninsula/northern Queensland. Such older patterns
are overlaid by younger events, including dispersal from Southeast Asia, and
range expansions and contractions. Future palaeoecological and phylogenetic
investigations will illuminate the evolution of the AMT biome. Understanding the
biogeography of the AMT is essential to provide a framework for ecological
studies and the sustainable development of the region.

Biogeography of the Australian monsoon tropics

Savannas are the most fire-prone of the earth’s major biomes. The availability of various broad-scale satellite-derived fire mapping and regional datasets provides a framework with which to examine the seasonality, extent and implications of large fires with particular reference to biodiversity values in the tropical savannas of northern Australia. We document the significance of savanna fires in the fire-prone ‘Top End’ region of the Northern Territory, Australia, using 9 years (1997–2005) of National Oceanic and Atmospheric Administration (NOAA)-Advanced Very High Resolution Radiometer (AVHRR)-, Landsat Thematic Mapper (TM)- and Enhanced Thematic Mapper (ETM+)-derived fire mapping. Fire (patch) sizes from both AVHRR- and Landsat-scale mapping increased through the calendar year associated with progressive curing of grass and litter fuels. Fire frequency data at both satellite sensor scales indicate that regional fire regimes in higher rainfall regions are dominated by large (>1000 km2) fires occurring typically at short (~2–3 years) fire return intervals. In discussion, we consider the ecological implications of these patch size distributions on regional fire-sensitive biota. Collectively, assembled data illustrate that many northern Australian savanna flora, fauna and habitats embedded within the savanna matrix are vulnerable to extensive and frequent fires, especially longer-lived obligate seeder plant taxa and relatively immobile vertebrate fauna with small home ranges.

Big fires and their ecological impacts in Australian savannas: size and frequency matters

Long-term fire experiments in savannnas are rare, given the difficulties and demands of operation. Controlled fire experiments date from colonial times in West Africa, although the largest and best-known is located in the Kruger National Park, South Africa. The achievements of these experiments are assessed from examples in Africa, South America and Australia. A less well-known experiment in Zimbabwe was sited at the Marondera Grassland Research Station and ran from 1953 to 1991. Some of the preliminary results on the impact of fire on vegetation are analysed and compared with further vegetation surveys in 2007. Studies on tree growth in this miombo savanna woodland indicate that the plots burned at three- and four-year intervals recovered to greater mean heights than the unburned control plots. There was no significant variation between treatments, suggesting that the few trees that did survive in the frequently burned plots were large specimens. Brachystegia and Julbernadia dominated the plots throughout and after the experiment. Basal area and stocking density were highest in the four-yearly burned plots but there was a high variability throughout the experiment, suggesting that many trees may have attained heights and bark thicknesses sufficient to protect from fire damage. Fire also affected the composition of the herbaceous plant community, but not the number of species. By the end of the experiment some grass and sedge species had flourished while others revealed greater susceptibility to fire, and fire-tolerant species predominated in the most frequently burned areas. The experimental design appeared to cope well with the variability between plots and indicated the soundness of the initial design and its implementation.

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Savanna burning and the assessment of long-term fire experiments with particular reference to Zimbabwe

Fragmentation is a severe threat to tropical rainforests.
However the habitat loss and less extensive fragmentation
caused by roads can also be a threat, not only through allowing access to remote areas, but also through a suite of insidious associated impacts. These include abiotic and biotic edge effects adjacent to road clearings, the disturbance impacts caused by vehicle operation, invasions by weeds, feral and alien fauna and disease, and faunal mortality from vehicle collisions. In combination, these can create a significant barrier to movements of rainforest biota. Impacts can be ameliorated through clever road design and sustainable vehicle operation.

Fragmentation impacts caused by roads through rainforests

Changes in net area of tropical forest are the sum of several processes: deforestation, regeneration of previously deforested areas, and the changing spatial location of the forest–savanna boundary. The authors conducted a long-term (1986–2006) quantification of vegetation change in a 5400 km2 forest–savanna boundary area in central Cameroon. A cross-calibrated normalized difference vegetation index (NDVI) change detection method was used to compare three high-resolution images from 1986, 2000, and 2006. The canopy dimensions and locations of over 1000 trees in the study area were measured, and a very strong relationship between canopy area index (CAI) and NDVI was found. Across 5400 km2 12.6% of the area showed significant positive change in canopy cover from 1986 to 2000 (0.9% yr−1) and 7.8% from 2000 to 2006 (1.29% yr−1), whereas <0.4% of the image showed a significant decrease in either period. The largest changes were in the lower canopy cover classes: the area with <0.2 m2 m−2 CAI decreased...

/pdf/measuring-woody-encroachment-along-a-forest-savanna-boundary-4t3l9ielcj.pdf

Measuring Woody Encroachment along a Forest–Savanna Boundary in Central Africa

Fire is a significant determinant of vegetation structure in Australia’s savannas and has been implicated in the decline of many species. Identifying the patterns of fire in the landscape is fundamental to understanding vegetation dynamics but variation over time and space makes generalization difficult and specific management
recommendations elusive. In order to improve the knowledge base for fire management in tropical savannas, we
investigated interregional variation in fire patterns in two Queensland bioregions, the Mount Isa Inlier (MII) and
Cape York Peninsula (CYP), over a 5-year period (1999–2003). Remotely sensed satellite data were used to identify burnt areas on a monthly basis for the western half of the CYP bioregion and about two-thirds of the smaller MII. Fire scars were mapped from JPEG-compressed, low-resolution Landsat images using geographical
information system technology and data were investigated to determine annual burning patterns. Patterns were interpreted with regard to meteorological information and recent fire history. The area burnt per annum on western
CYP was generally an order of magnitude greater than the area burnt on the MII. In the biggest fire year, nearly
74% (5 295 098 ha) of the CYP landscape burnt, compared with 35% (1 770 771 ha) of the MII landscape. The minimum percentage of the CYP study area burnt in 1 year between 1999 and 2003 was 43.1%, compared with 1.6% for the MII. The reliability and amount of seasonal rainfall was a strong determinant of differences in time of fire occurrence and area burnt between regions. Widespread wildfires were significantly related to above average
rainfall in the preceding 12 months in the Mt. Isa area but not in CYP. Rainfall also affected fire frequency.
Predictable wet season rainfall on CYP allowed for a biennial fire return interval, while on the semiarid MII, the average fire return interval was 5 years or longer. We conclude that the fire patterns in the semiarid MII are similar to those reported for arid Australia, while fire patterns in western CYP are comparable with other mesic savanna areas.

Comparison of fire patterns and fire frequency in two tropical savanna bioregions

Lumholtz's Tree-kangaroo Dendrofagus lumholtzi is endemic to the rainforests of north Queensland, Australia. Most records of D. lumholtzi are from upland forests on the Atherton Tablelands, an area -extensively cleared for agriculture. In 1997, residents of the Tablelands formed the Tree Kangaroo and Mammal Group Inc. (TKMG) with the aim of promoting the conservation of the species. The first project of TKMG was an intensive community-based survey of the
distribution of D. fumholtzi. Residents of all postal districts encompassing areas of upland rainforest within the range of D. lumholtzi were sent a written questionnaire seeking details of tree-kangaroo sightings. The Malanda postal district was surveyed in 1998 while all other postal districts were surveyed in 1999. In total, 10 122 questionnaires were distributed in the survey. Nearly BOO responses were received to the survey, providing 2 36B Sighting records of D. lumholtzi. Of these, 367 records were of dead tree-kangaroos, mostly road-kills." The survey has provided a much more comprehensive account of the distribution of the species than was previously available. Most records of D. lumholtz; obtained in the survey were from upland forests between Atherton and Ravenshoe, particularly remnant forests in the central and western Tablelands. Although the survey methodology is biased towards areas frequented by humans, these patterns are consistent with independent surveys. The conservation of D. lumholtzi on the Tablelands would benefit from the protection of remnant forests, the restoration of habitat and a reduction in the incidence of road-kills and dog attacks on tree-kangaroos.

Community survey of the distribution of Lumholtz's Tree-kangaroo on the Atherton Tablelands, north-east Queensland

Unplanned, unmanaged wildfires are a significant threat to people, infrastructure and ecosystems around the world. Managed, planned burning is widely used for reducing the incidence, extent or intensity of wildfires. Fire weather and the season of burning are recognised as crucial factors influencing fire behaviour but the demonstrated influence of ignition technique on fire behaviour is not as prominently discussed in relation to planned fires. We found wildfires, irrespective of season, burnt the ground layer more completely (i.e. were less patchy) and produced greater crown scorch severity than did planned fires in a spinifex (Triodia spp.)-dominated open woodland. Fires ignited with a 50-m line burning with the wind produced significantly higher intensities than did line ignition against the wind, and spot ignitions with or against the wind. These data suggest that the higher severity of wildfires in spinifex-dominated habitats is strongly influenced by long fire fronts, in addition to fire season and weather conditions. This study supports the value of planned burning for reducing fire severity and highlights the value of spot ignitions in ecological burning to create a patchily burnt landscape, with limited canopy severity.

The influence of ignition technique on fire behaviour in spinifex open woodland in semiarid northern Australia

Research into fire ecology has culminated in ‘the patchiness paradigm’ This is the view that numerous small fires, with variety in fire timing, frequency and intensity, will lead to habitat diversity across the landscape, thereby benefiting species conservation The paradigm recognises that fire is instrumental in shaping the Australian environment, and that no single fire regime will suit all species As a result, land holders wanting to adopt ecologically sustainable fire management practices are advised to develop and maintain fine-grained landscape patchiness using fire However, there is no guidance on optimal fire size, level of internal fire patchiness or desirable fire frequency Having ill-defined objectives is incompatible with ‘adaptive management’, the approach espoused for managing in the face of inadequate information and uncertainty Adaptive management, or learning by doing, requires clear management objectives and careful monitoring When, how often, and how much should manager’s burn, and how should they evaluate success? Although adaptive management accommodates uncertainty, the scale and internal patchiness of proposed fire operations need to be articulated in order to commence the cycle with a ‘best guess’ management target Addressing this issue and bridging the gap between ecological understanding and applied land management is the critical next step in fire ecology This thesis focuses on this concern

The case study area was the Mount Isa Inlier, a semi-arid bioregion in northwest Queensland, Australia The study concentrated on the fire ecology of spinifex/snappy gum woodlands, the dominant vegetation type in the bioregion Remote sensing technology was used to examine landscape fire patterns and to identify key drivers of these patterns Field surveys were undertaken to determine regenerative responses of the vegetation and to investigate spatial variability between and within fires To investigate the potential effects on fauna, a fauna fire response database was compiled using expert opinion Species were then classified according to their fire sensitivity based on species’ refugium requirements during a fire and vegetation maturation stage requirements after a fire The predicted response of fauna was tested in the field using birds as a sub-group The results were interpreted in terms of setting objectives for adaptive management, with recommendations on a target fire size and associated monitoring The Mount Isa Inlier was found to have greater affinity with arid Australian landscapes than mesic savannas Fire scars mapped over a six-year period (1998-2003) showed that the total area burnt per year was related to the strength of the preceding wet season Post-fire changes in the vegetation were highly predictable There was a flush of annual and ephemeral species after the first rain The abundance of these species decreased over time, while the cover of perennial species increased There was insufficient fuel for fire to spread for at least three years from the previous fire By then, most ephemeral species have set seed, and perennial species have started to produce seeds Resilience to fire was enhanced by the inherent variability within burnt areas Vegetation at early recovery stages co-existed with patches of vegetation at later recovery stages Mature plants in unburnt patches provide reproductive material that ensures individual species remain in the system Collectively, these data provided an understanding of firemediated vegetation dynamics in spinifex/snappy gum communities When the fire-sensitivity of fauna species was tested, birds relying on long unburnt spinifex during and after fire were more vulnerable than generalist species

Additional field studies were undertaken to investigate the internal fire-patchiness requirements of fire-sensitive species The ideal characteristics for unburnt patches within fire scars could not be defined Nonetheless the approach provided sufficient insight for a target fire size to be proposed Restricting fire size to around 100 ha was considered acceptable to conserve birds in the bioregion It is recommended that a suite of fire-sensitive species be used for ecological monitoring, based on the objective process used in this study Fine-scale satellite imagery (IKONOS, 1-m2 – 4-m2 pixel resolution) was investigated as a tool for quantifying fire patchiness If fuel load or fire severity could be mapped, this would provide the initial step Mapping fuel loads at this scale would also give accurate and spatially explicit fire histories for different areas This would benefit researchers interested in characterising fire regimes as it would allow for successive monitoring Field data on fuel load and fire severity were compared to reflectance values recorded by the IKONOS satellite A fuel load map was produced, but the inherent uncertainty in remote sensing processes meant that results were generalised to areas with high, medium or low fuel load Although this can assist managers to identify areas of high fire hazard, its day-to-day use for monitoring fire patchiness is questionable Mapping fire severity was not successful and remains the key fire regime variable not yet captured by remote sensing The fine-scale mapping components of this study supported the notion that restricting fire size should be emphasised as a management goal in northwest Queensland Internal fire-patchiness was inherent and difficult to specifically plan for Fire size can be readily monitored using existing remote sensing techniques

The major contribution of this work is that it provides a way to mesh the patchiness paradigm with practical land management By tailoring fire size to the needs of the most fire sensitive species, the remainder are likely to be catered for, by default Fire-sensitive species can be identified by classifying species according to their requirements during, and immediately after, fire The method tested here proved to be useful and can be applied in different environments and at different scales This is one of the few studies that endeavours to quantify the level of patchiness to which managers might aspire It demonstrates a strategic approach that integrates well with adaptive management Thus, the findings provide a way to progress from setting management goals based on ecological principles, such as ‘a fine scale mosaic’, to setting more specific targets based on ecological understanding and a coherent process Further, the thesis provides important information on the fire ecology of spinifex/snappy gum woodlands in the Mount Isa Inlier Fire-related research is scant for this area, so this information provides a starting point for ecological fire management in the region

The fire patchiness paradigm: a case study in northwest Queensland

This report provides a preliminary assessment of Unmanned Aerial Vehicle (UAV) technology for precision agriculture. It focuses on the macadamia industry, but an assessment is given of industry progress in other farming areas. Regardless of crop type, the principles of image capture and interpretation are the same, so insights gained elsewhere are highly relevant. Examples of geo-referenced imagery are provided, along with a photo-mosaic, to demonstrate the image processing steps before the aerial photography can be imported into a geographic information system (GIS) and used with other data layers to interpret management requirements or outcomes. A qualitative assessment of the strengths, weaknesses, opportunities and threats associated with the technology is given, as well as recommendations for its further development to meet horticultural needs

Leasie Felderhof

Papers

Comparison of fire patterns and fire frequency in two tropical savanna bioregions

Community survey of the distribution of Lumholtz's Tree-kangaroo on the Atherton Tablelands, north-east Queensland

The influence of ignition technique on fire behaviour in spinifex open woodland in semiarid northern Australia

The fire patchiness paradigm: a case study in northwest Queensland

Linking UAV (unmanned aerial vehicle) technology with precision agriculture