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Contemporary fire regimes are recognized as a key threatening process for relatively immobile vertebrates and narrowly dispersing obligate seeder plant taxa in fire‐prone Australian savannas. Here, we assess the efficacy of proposed ecological performance threshold metrics for evaluating the current state of fire management for biodiversity conservation outcomes in Australia's premier, and best publicly funded savanna reserve, Kakadu National Park. The assessment draws on available data describing Landsat‐scale fire mapping over the period 1997–2015, habitat mapping, and mostly modeled responses of vegetation and faunal attributes. Despite conceptual and technical issues associated with various proposed performance thresholds and mapping products, the assessment demonstrates significant challenges with the current state of the reserve's fire management program. For example, by the end of 2015 it was observed that just 6% of woodland habitat in lowland and 23% in upland situations had remained unburnt for longer than three years and 98% of mapped fires in lowland and 87% in upland habitats were >1 km2 in extent. Of 14 assessed performance threshold metrics, two were within acceptable thresholds at the end of 2015, and none had improved materially over the decadal assessment period. Given substantial resources evidently required to deliver effective, seasonally intensive, fine‐grained adaptive fire management for biodiversity conservation outcomes in fire‐prone Australian savannas, we suggest that alternative resourcing opportunities through market‐based savanna burning greenhouse gas emissions abatement projects need to be explored.

Context. Australia has a lamentable history of mammal extinctions. Until recently, the mammal fauna of northern Australia was presumed to have been spared such loss, and to be relatively intact and stable. However, several recent studies have suggested that this mammal fauna may be undergoing some decline, so a targeted monitoring program was established in northern Australia’s largest and best-resourced conservation reserve. Aims. The present study aims to detect change in the native small-mammal fauna of Kakadu National Park, in the monsoonal tropics of northern Australia, over the period of 1996–2009, through an extensive monitoring program, and to consider factors that may have contributed to any observed change. Methods. The small-mammal fauna was sampled in a consistent manner across a set of plots established to represent the environmental variation and fire regimes of Kakadu. Fifteen plots were sampled three times, 121 plots sampled twice and 39 plots once. Resampling was typically at 5-yearly intervals. Analysis used regression (of abundance against date), and Wilcoxon matched-pairs tests to assess change. For resampled plots, change in abundance of mammals was related to fire frequency in the between-sampling period. Key results. A total of 25 small mammal species was recorded. Plot-level species richness and total abundance decreased significantly, by 54% and 71%, respectively, over the course of the study. The abundance of 10 species declined significantly, whereas no species increased in abundance significantly. The number of ‘empty’ plots increased from 13% in 1996 to 55% in 2009. For 136 plots sampled in 2001–04 and again in 2007–09, species richness declined by 65% and the total number of individuals declined by 75%. Across plots, the extent of decline increased with increasing frequency of fire. The most marked declines were for northern quoll, Dasyurus hallucatus, fawn antechinus, Antechinus bellus, northern brown bandicoot, Isoodon macrourus, common brushtail possum, Trichosurus vulpecula, and pale field-rat, Rattus tunneyi. Conclusions. The native mammal fauna of Kakadu National Park is in rapid and severe decline. The cause(s) of this decline are not entirely clear, and may vary among species. The most plausible causes are too frequent fire, predation by feral cats and invasion by cane toads (affecting particularly one native mammal species). Implications. The present study has demonstrated a major decline in a key conservation reserve, suggesting that the mammal fauna of northern Australia may now be undergoing a decline comparable to the losses previously occurring elsewhere in Australia. These results suggest that there is a major and urgent conservation imperative to more precisely identify, and more effectively manage, the threats to this mammal fauna.

African para grass (Urochloa mutica) is an invasive weed that has become prevalent across many important freshwater wetlands of the world. In northern Australia, including the World Heritage landscape of Kakadu National Park (KNP), its dense cover can displace ecologically, genetically and culturally significant species, such as the Australian native rice (Oryza spp.). In regions under management for biodiversity conservation para grass is often beyond eradication. However, its targeted control is also necessary to manage and preserve site-specific wetland values. This requires an understanding of para grass spread-patterns and its potential impacts on valuable native vegetation. We apply a multi-scale approach to examine the spatial dynamics and impact of para grass cover across a 181 km2 floodplain of KNP. First, we measure the overall displacement of different native vegetation communities across the floodplain from 1986 to 2006. Using high spatial resolution satellite imagery in conjunction with historical aerial-photo mapping, we then measure finer-scale, inter-annual, changes between successive dry seasons from 1990 to 2010 (for a 48 km2 focus area); Para grass presence-absence maps from satellite imagery (2002 to 2010) were produced with an object-based machine-learning approach (stochastic gradient boosting). Changes, over time, in mapped para grass areas were then related to maps of depth-habitat and inter-annual fire histories. Para grass invasion and establishment patterns varied greatly in time and space. Wild rice communities were the most frequently invaded, but the establishment and persistence of para grass fluctuated greatly between years, even within previously invaded communities. However, these different patterns were also shown to vary with different depth-habitat and recent fire history. These dynamics have not been previously documented and this understanding presents opportunities for intensive para grass management in areas of high conservation value, such as those occupied by wild rice.

Dean, J.C., 2001. New species of Hydropsychidae (Insecta: Trichoptera) from northern Australia. Memoirs of Museum Victoria 58(2):231–246. Five new species of hydropsychid caddisflies of northern Australia are described from males, females and larvae: Cheumatopsyche kakaduensis sp. nov., C. suteri sp. nov., C. wellsae sp. nov., C. dostinei sp. nov. and Asmicridea capricornica sp. nov. Cheumatopsyche kakaduensis sp. nov. has thus far only been recorded from Kakadu National Park, while the remaining four species are widely distributed across northern Australia. Distribution maps are presented with keys for identification of males, females and larvae.

ISSN 1948-6596 news and update update From acorns mighty micropockets grow Dispersal processes may be critical in determining rates of species range shifts under future climate change. Travis Marsico, Jessica Hellman and Jeanne Romero-Severson, writing in the Journal of Biogeography, shed new light on the future by examining the past shifts in Oregon oak since the Last Glacial Maximum (LGM) (Marsico et al. 2009). They find that it doesn't take a village, it just takes a single tree. This helps support an emerging new view of how plant range shifts are realized when climate shifts rapidly. Until recently, prevailing concepts of bio- logical response to rapid warming in North Amer- ica and Europe were of large, monolithic range shifts in which species totally vacated habitat of waning suitability, moving to new, completely dis- junct range. This view began to change in 1995 when Matt McGlone and Vera Markgraf pre- sented a starkly contrasting model of vegetation shift in the Southern Hemisphere. In New Zealand, McGlone found recolonization of the South Island to be much more rapid than could be accounted for by long-distance dispersal (McGlone 1995). In southern South America, Markgraf documented vegetation change keeping pace with extremely rapid climate 'flickers' (Markgraf and Kenny 1995). Both authors suggested that micropockets of vegetation could explain the very rapid observed changes in dominant vegetation. Such micropock- ets of vegetation were very plausible in these southern settings where no large continental ice sheets existed. Evidence has since grown that micropockets may be important in Northern Hemisphere set- tings as well (recent literature is briefly reviewed by Marsico et al.). Tree remains very close to the boundary of the ice sheet have been found in pa- leorecords of both Europe and North America. Pollen signatures that were previously assumed to be from long-distance blow-in are now being rein- terpreted as possible evidence of vegetation mi- cropockets. If the growing consensus around micro- pockets is correct, the implications for vegetation response to future, human-induced climate change is profound. Patches of vegetation of a few tens of meters on a side might provide source material at rapidly expanding range margins. Long-distance dispersal might establish micro- pockets of vegetation that would serve as step- ping-stones for additional long-distance dispersal. Marsico et al. show that in Oaks in the Pa- cific Northwest, dispersal was primarily from indi- viduals on the leading edge of the range. Chloro- plast DNA markers were remarkably homogenous in their samples. At 16 of 22 sites all individuals sampled shared a single chloroplast haplotype. Having identical chloroplast haplotype indicates a common maternal ancestor, so these populations were established from single colonizations or mul- tiple colonizations by seeds from the same tree (which seems much less likely). The implication is that single trees are criti- cal for establishing populations in newly suitable range. Micropockets of vegetation would have ample sources of seeds for range shifts, if all it takes is a single tree. Marsico et al. found much more diversity in nuclear DNA, indicating that once single colonizations occur, populations grow and are diversified by wide pollen flow from many individuals. Colonists from micropockets and di- versity from broader populations may be a key mechanism in rapid range shifts as rapid human- induced climate change gathers force. Markgraf, V. & Kenny, R. (1995) Character of rapid vegetation and climate change during the late- glacial in southernmost South America. In Hunt- ley, B., Cramer, W., Morgan, A.V., Prentice, H.C. and Allen, J.R.M. (eds.) Past and Future Rapid Environmental Changes: The Spatial and Evolu- tionary Responses of Terrestrial Biota, pp. 81- 102. Springer-Verlag, Berlin. Marsico, T.D., Hellmann, J.J. & Romero-Severson, J. (2009) Patterns of seed dispersal and pollen flow in Quercus garryana (Fagaceae) following post-glacial climatic changes. Journal of Bio- geography, 36, 929-941. McGlone, M.S. (1995) The responses of New Zealand forest diversity to Quaternary climates. In Hunt- ley, B., Cramer, W., Morgan, A.V., Prentice, H.C. frontiers of biogeography 1.1, 2009 — © 2009 the authors; journal compilation © 2009 The International Biogeography Society

The discovery of a 'hairy' yellow weevil in Kakadu National Park in 1995, akin to a widely distributed pest species of agricultural crops in South-East Asia (but not Australia), the so-called 'Gold-dust Weevil' (Ilypomeces 'squamosa?), prompted us to investigate the taxonomy and distribution of this weevil in order to determine the identity and origin of the Kakadu specimen. The 'Gold-dust Weevil', whose correct scientific name is H. pttlinger (Herbst, 1795), is a sexually dimorphic and variable species and has been described under various names in the literature, but its taxonomy and nomenclature have never been investigated. The results of our research to date indicate that it comprises a complex of closely similar species and that the Australian specimen is not conspccific with those occurring further west and north in South-East Asia. We also found that a female conspccific with the Kakadu specimen was likely collected by Captain Phillip Parker King during his surveys of the northern Australian coast in about 1820 and described in 1826 by W. S. Macleay as Cenchroma obscura. King's weevil has been forgotten for over 200 years, but the discovery of the Kakadu specimen suggests that this species, correctly named Hjpomeces obsfurus, may be present in northern Australia, albeit scarce and seemingly of no current agricultural concern.

For all mangroves in Kakadu National Park in Australia's Northern Territory, /spl sim/1 m spatial resolution orthomosaics and Digital Elevation Models (DEMs) were generated. For the West Alligator River, tree density was also estimated from the photography and Compact Airborne Spectrographic Imager (CASI) data were acquired to differentiate and map the main zonations. These datasets combined represent a key baseline against which to observe and quantify future changes in the extent, height, density, species/community composition and also above ground biomass of mangroves resulting from, for example, sea level rise.

Changes in the abundance and biomass of aquatic and terrestrial aerial insects with distance (mid‐stream, 0, 10–15 and 160 m) from lowland streams were examined across the dry season landscape in Kakadu National Park, northern Australia. Malaise traps and sticky intercept traps were used to sample the insects at four streams, spaced over an area of 1650 km2. Malaise and intercept catches were dominated by Diptera (flies and midges), both numerically and by biomass. Chironomid midges were the most abundant taxon, making up 43.4 and 51.0% of the malaise and intercept trap catches, respectively. However, most chironomids were small (less than 3 mm body length), contributing 34.9% to intercept trap biomass, but only 5.2% in malaise traps. Ceratopogonid midges and caddisflies (Trichoptera) accounted for most of the remaining adult aquatic insects. Major terrestrial components were Diptera and Hymenoptera in malaise traps and Coleoptera and Diptera in intercept traps. The total abundance and biomass of insects were much greater over streams and along the water's edge than in riparian (10–15 m) and savanna (160 m) habitats primarily because of the presence of large numbers of adult aquatic insects. The abundance and biomass of terrestrial insects in malaise traps showed no relationship with distance, but intercept trap catches suggested slightly greater abundances over the water and at the water's edge. The great abundance of aquatic insects relative to terrestrial insects close to streams suggests that they have the potential to be an important component of the diets of riparian insectivores, and predation may be an important pathway by which aquatic nutrients and energy are moved into terrestrial food webs.

A previous study (Braithwaite & Muller 1997) reported substantial declines in mammal abundance over the period 1986–1993 for a large study area (300 km2) within Kakadu National Park in the tropical savannas of northern Australia. This decline was reported as being a ‘natural’ response to fluctuating groundwater levels, driven by runs of poor wet seasons. We resampled mammals in this area in 1999, following a series of unusually good wet seasons, and examined the prediction that mammal numbers should have recovered. Increases in abundance were evident for four species: the smallest dasyurid (red-cheeked dunnart Sminthopsis virginiae) and the three smallest rodents (delicate mouse Pseudomys delicatulus, western chestnut mouse Pseudomys nanus and grassland melomys Melomys burtoni). In contrast, the abundance of all mammals combined and that for seven individual mammal species (northern quoll Dasyurus hallucatus, fawn antechinus Antechinus bellus, common brushtail possum Trichosurus vulpecula, northern brown bandicoot Isoodon macrourus, dusky rat Rattus colletti, black-footed tree-rat Mesembriomys gouldii and pale field rat Rattus tunneyi) continued to decline. The decline in abundance of these mammal species is consistent with limited observations elsewhere in northern Australia. Although far from conclusive, these observations suggest that the biota of the vast relatively undisturbed tropical savannas can no longer be assumed to be intact nor safe. Further research is needed to test this possible pattern of decline and, if confirmed, to identify and ameliorate the processes contributing to it.

1. Globally, tropical floodplains are highly productive ecosystems. This is largely because of predictable seasonal rains providing replenishing floodwaters that stimulate nutrient turnover which, in turn, substantially boosts both primary and secondary productivity. This is associated with concomitant shifts in the types of primary producers and associated food webs. 2. The Magela Creek floodplain on Kakadu National Park in northern Australia is one of the most studied tropical freshwater ecosystems in Australia and provides an opportunity to collate and examine information on organic carbon sources and pathways through food webs to gain a fundamental understanding of how these systems may function. 3. We reviewed biophysical information published since the early 1980s to construct an assessment of the carbon resources for the channel and floodplain. 4. We conclude that macrophytes, largely in the form of grasses and aquatic plants, produce the greatest above-ground biomass on the Magela Creek floodplain. Although macrophytes provide suitable substrata for the attachment of epiphytes, they do not appear to be an important carbon source for aquatic consumers themselves. Nevertheless, macrophytes do provide critical seasonal food and habitat structure for other producers and consumers on the floodplain, such as the abundant magpie geese. 5. We developed a generalised conceptual food web and carbon budget contrasting the ‘wet’ and ‘dry’ seasons for the Magela Creek system, as a representative of tropical seasonal floodplain systems. 6. Our conceptual model of tropical floodplains indicates that knowledge of the seasonal and spatial links and exchanges between the floodplain and the river is critical in understanding ecosystem function.

Context Green turtles (Chelonia mydas) are listed as vulnerable in Australia and are culturally significant to Indigenous Traditional Owners. However, their foraging habitats remain poorly understood, particularly in northern Australia. Aims To map green turtle foraging habitats in the Northern Territory, through collaboration with Traditional Owners and ranger groups to support Sea Country management. Methods Visual classifications of towed video transect data were used in a Support Vector Machine Learning Model to predict habitat across 379 km2 of remotely sensed satellite imagery, encompassing two green turtle foraging grounds within jointly managed parks, namely, Trepang Bay (Garig Gunak Barlu Marine Park) and Field Island (Kakadu National Park). Key results Foraging turtle habitat; algae and seagrass made up 30% of the Trepang Bay and 18.05% of the Field Island foraging areas. The classification accuracy of the model showed a high level of agreement at both sites (0.63 and 0.75 respectively). Conclusion These habitats provide good foraging grounds for green turtles and support different age classes for various behaviours, including resting and predator avoidance. Implications The simple and repeatable field methods used in this study allow for ongoing monitoring by ranger groups. The findings will support conservation planning and management in the Northern Territory.

Constructive and destructive interference have long been a significant problem for the classification of radar imagery. Several authors have noted the ability of segmentation to work around the problem by incorporation of spatially adaptive filters and fuzzy logic. We present the methodology and results of such a study using multitemporal datasets in the place of multispectral data. For the study 27 standard and ScanSAR images were collected over the region from 1996 to 2001. The majority of the images were S4 ascending, with ScanSAR narrow collected simultaneously. The ScanSAR images allowed us to assess the methodology over a wider swath, yielding results on a regional rather than local scale. Northern Australia exhibits an extremely seasonal climate. The monsoonal nature of this climate means a huge variation in the amount of available water to plant life both on and surrounding the flood plains of the major river systems. Within this area is Kakadu National Park, a heritage listed and Ramsar identified wetland of international significance. Kakadu has a long history of scientific study, and is an ideal site on which to conduct studies such as this. The seasonal nature of this area presents a unique opportunity, that of a worst case scenario for classification schemes, whereby each location on the flood plain undergoes significant change over the seasonal cycle, similar in many respects to the change between bands of a multi-spectral dataset. A modified Gaussian Markov random field model segmentation routine was used to cluster areas exhibiting similar radar response (both numerical and textural) at each successive date in the time series. For each date cluster statistics were then generated. This allowed the construction of temporal curves due to the fact that as the target material dries the material's dielectric constant decreases. As dielectric constant is significantly dependent on water content, these temporal curves act as a proxy measure for water availability, and hence aid in the discrimination of wetland from non-wetland areas and any change in size and location of these areas throughout the season. The output of the segmentation routine is a series of three bands. The first and second bands are the statistics (mean and standard deviation) of the original image and the third a vector file of the edge locations. By outputting statistical information instead of arbitrary segment number standard classification routines may be used successfully on radar imagery. Classification of the results of the segmentation may be either supervised or unsupervised, however analysis indicated that the Isodata algorithm adequately addressed classification needs. As a combined system the segmentation and classification system used in this paper has shown some excellent results when applied to multi-date radar imagery of Kakadu National Park in Northern Australia. Results for a segmentation of multitemporal radar dataset are presented alongside the results of the subsequent classification. By creating a system that requires minimal user input a wide variety of applications may be addressed. Indeed, the registration of the imagery becomes the most user intensive portion of the process. Automated routines such as this allow for analysis of large areas on a regular basis, an exceptional result for monitoring change and establishing baselines for later comparison.

ABSTRACTThe abundance and distribution of reptiles and amphibians inhabiting tropical monsoonal wetlands in Kakadu National Park, northern Australia, were monitored between late 1979 and 1982. Seasonal trends in species richness, and the influence of various environmental attributes (including those caused by feral ungulates) on species distribution patterns were also examined.These wetlands support a high proportion of the amphibian species known from the Park, but are of less importance to reptiles. Within the wetlands, the structurally more complex forested ‘margins’ support many more species than the treeless floodplains. Amphibian species distributions seem to be influenced primarily by elevation, through its effects on soil moisture and flooding levels, while reptile distribution patterns reflect a more complex set of environmental factors, with structural attributes (e.g. vegetation height structure and cover, refuge abundance, leaf litter cover and depth, extent of flooding) being of prime importance.Feral buffalo and pigs, through their grazing, trampling and wallowing, may considerably influence such structural attributes and change the duration and extent of water lie, and thus indirectly affect species distribution patterns. Current buffalo culling programmes provide an opportunity to monitor vegetation and faunal changes, and quantify feral animal impactpost facto.

Global warming and anthropogenic activities have imposed noticeable impacts on rainfall pattern changes at both spatial and temporal scales in recent decades. Systematic diagnosis of rainfall pattern changes is urgently needed at spatiotemporal scales for a deeper understanding of how climate change produces variations in rainfall patterns. The objective of this study was to identify rainfall pattern changes systematically under climate change at a subcontinental scale along a rainfall gradient ranging from 1800 to 200 mm yr−1 by analyzing centennial rainfall data covering 230 sites from 1910 to 2017 in the Northern Territory of Australia. Rainfall pattern changes were characterized by considering aspects of trends and periodicity of annual rainfall, abrupt changes, rainfall distribution, and extreme rainfall events. Our results illustrated that rainfall patterns in northern Australia have changed significantly compared with the early period of the twentieth century. Specifically, 1) a significant increasing trend in annual precipitation associated with greater variation in recent decades was observed over the entire study area, 2) temporal variations represented a mean rainfall periodicity of 27 years over wet to dry regions, 3) an abrupt change of annual rainfall amount occurred consistently in both humid and arid regions during the 1966–75 period, and 4) partitioned long-term time series of rainfall demonstrated a wetter rainfall distribution trend across coastal to inland areas that was associated with more frequent extreme rainfall events in recent decades. The findings of this study could facilitate further studies on the mechanisms of climate change that influence rainfall pattern changes. Significance Statement Characterizing long-term rainfall pattern changes under different rainfall conditions is important to understand the impacts of climate change. We conducted diagnosis of centennial rainfall pattern changes across wet to dry regions in northern Australia and found that rainfall patterns have noticeably changed in recent decades. The entire region has a consistent increasing trend of annual rainfall with higher variation. Meanwhile, the main shifting period of rainfall pattern was during 1966–75. Although annual rainfall seems to become wetter with an increasing trend, more frequent extreme rainfall events should also be noticed for assessing the impacts of climate changes. The findings support further study to understand long-term rainfall pattern changes under climate change.

Root Biomass and Distribution Patterns in a Semi-Arid Mesquite Savanna: Responses to Long-Term Rainfall Manipulation