Lindenmayer D.B.,Australian National University |
Gibbons P.,Australian National University |
Bourke M.,The Thomas Foundation |
Burgman M.,University of Melbourne |
And 24 more authors.
Austral Ecology | Year: 2012
Effective biodiversity monitoring is critical to evaluate, learn from, and ultimately improve conservation practice. Well conceived, designed and implemented monitoring of biodiversity should: (i) deliver information on trends in key aspects of biodiversity (e.g. population changes); (ii) provide early warning of problems that might otherwise be difficult or expensive to reverse; (iii) generate quantifiable evidence of conservation successes (e.g. species recovery following management) and conservation failures; (iv) highlight ways to make management more effective; and (v) provide information on return on conservation investment. The importance of effective biodiversity monitoring is widely recognized (e.g. Australian Biodiversity Strategy). Yet, while everyone thinks biodiversity monitoring is a good idea, this has not translated into a culture of sound biodiversity monitoring, or widespread use of monitoring data. We identify four barriers to more effective biodiversity monitoring in Australia. These are: (i) many conservation programmes have poorly articulated or vague objectives against which it is difficult to measure progress contributing to design and implementation problems; (ii) the case for long-term and sustained biodiversity monitoring is often poorly developed and/or articulated; (iii) there is often a lack of appropriate institutional support, co-ordination, and targeted funding for biodiversity monitoring; and (iv) there is often a lack of appropriate standards to guide monitoring activities and make data available from these programmes. To deal with these issues, we suggest that policy makers, resource managers and scientists better and more explicitly articulate the objectives of biodiversity monitoring and better demonstrate the case for greater investments in biodiversitymonitoring. There is an urgent need for improved institutional support for biodiversity monitoring in Australia, for improved monitoring standards, and for improved archiving of, and access to, monitoring data. We suggest that more strategic financial, institutional and intellectual investments in monitoring will lead to more efficient use of the resources available for biodiversity conservation and ultimately better conservation outcomes. © 2011 The Authors. Journal compilation © 2011 Ecological Society of Australia.
Pixel-based image classification to map vegetation communities using SPOT5 and Landsat5 Thematic Mapper data in a tropical savanna, northern Australia [Classification dimages à base de pixels pour les communautés végétales carte à laide de données SPOT5 et Landsat5 Thematic Mapper de la savane tropicale, le nord de lAustralie]
Lewis D.,University of Queensland |
Phinn S.,The Arts and Sport |
Pfitzner K.,Environment Water Population and Communities
Canadian Journal of Remote Sensing | Year: 2012
Pixel-based image classification has been used to capture various components of vegetation for a number of applications and at a range of spatial scales across the world. The few studies that have attempted to capture the floristic composition of vegetation communities in tropical savanna environments, at fine spatial scales (1:25 000 or less) using these methods, have found minimal success. To address this gap, we evaluated a supervised image classification process using the Maximum Likelihood Classifier and 50% of a floristic and structural (strata, cover, height, and growth form) field dataset applied to SPOT5 and Landsat5 Thematic Mapper multispectral data. Two approaches were conducted to evaluate the influence of ancillary data on classification results: (i) "image-only" (image and field data) and (ii) "integrated" (various combinations of ancillary data with the image and field data). Multivariate analysis and intuitive classification were employed to identify 22 vegetation communities within the 530 km2 study area situated on Bullo River Station, Northern Territory, Australia. Class (vegetation community) separability averaged 1.94 and 1.42 for Landsat5 Thematic Mapper and SPOT5, respectively. A standard accuracy assessment was based on the remaining 50% of the field data. Overall accuracy ranged from 30%-53% for 1:25 000 and 1:100 000 spatial scale products. The inclusion of ancillary data was superior to the image and field data alone. The results of this study emphasize the need for finer spatial scale maps for property management planning (5 1:25 000) and coarser scales for regional applications (≥ 1:100 000). © 2012 CASI.
Ferdinands K.,The Arts and Sport |
Virtue J.,Khan Research Laboratories |
Johnson S.B.,Industry and Investment New South Wales |
Setterfield S.A.,Charles Darwin University
Current Opinion in Environmental Sustainability | Year: 2011
The growth of the bioeconomy, and in particular the debate regarding the use of biofuels, highlights how innovation in agriculture driven by new policy initiatives, with the best of intentions (e.g. reducing carbon emissions and reliance on fossil fuels), may have unintended consequences. These unintended consequences include a variety of socioeconomic and environmental impacts that arise because of a decoupling of agricultural/industrial growth or innovation from consideration of environmental and social impacts. This issue is not new and has long existed in relation to the use of alien plants for production or ornamental purposes-hence our use of the term 'bio-insecurities'. We discuss the role and refinements needed in existing weed risk management systems and existing policies to achieve a more sustainable and defensible approach to the use of alien plants in the bioeconomy. © 2011.
Edwards A.,The Arts and Sport |
Edwards A.,Charles Darwin University |
Maier S.,Charles Darwin University |
Hutley L.,Charles Darwin University |
And 2 more authors.
34th International Symposium on Remote Sensing of Environment - The GEOSS Era: Towards Operational Environmental Monitoring | Year: 2011
The algorithm to calculate Greenhouse Gas (GHG) emissions from savanna fires relies upon a number of variables from the classification of satellite based optical imagery. The algorithm variables require continued refinement. Fire severity mapping will increase the accuracy of the spatial distribution of fuel consumed. Fire severity is the post-fire effect of fire on the vegetation. The fire severity mapping algorithm developed in this study correlated helicopter-based spectra collected over a site using a hand held spectrometer and ground data describing the fire severity within the spectrometer field of view. The differenced Normalized Burn Ratio (ΔNBR) quite clearly distinguished between severe and not-severe fires (r2 = 0.94). However, further discrimination into three or more classes required the development of other indices incorporating the region of the spectrum represented by MODIS band 6 (1628-1652 nm). This poses problems operationally as band 6 on Aqua is dysfunctional thus halving the available data.
Andersen A.N.,CSIRO |
Woinarski J.C.Z.,the Arts and Sport |
Woinarski J.C.Z.,Charles Darwin University |
Parr C.L.,University of Oxford
Austral Ecology | Year: 2012
Tropical savannas are the world's most fire-prone biome, and savanna biotas are generally well adapted to frequent fire. However, in northern Australia there are concerns that recent increases in the frequency and extent of high-intensity fires are causing substantial declines in regional biodiversity values. In this paper we use two well-studied and contrasting faunal groups, ants and small mammals, as case studies for reviewing faunal responses to fire in Australian savannas. The Australian savanna ant fauna is dominated by arid-adapted taxa that are highly resilient to frequent fire and are not considered to be threatened by prevailing fire regimes. Indeed, frequent fire promotes ant diversity because it maintains an open habit that makes the dominant arid-adapted taxa feel at home. Long-term fire exclusion reduces ant diversity due to a marked decline in arid-adapted taxa, and favours highly generalized, more shade-tolerant taxa. In contrast, many small mammal species of high conservation value are highly sensitive to frequent fire, and there are widespread concerns that their populations are threatened by current fire management. Many of the species have shown dramatic population declines over recent decades, and, although the causes are poorly understood, there is little doubt that fire is an important contributing factor. It is likely that fire is acting synergistically with other underlying causes of decline, particularly predation by feral cats. The overall resilience of most savanna animal species in relation to frequent fire suggests that they are secure under all but the most extreme fire regimes. However, it is clear that more fire-sensitive groups such as small mammals need special fire management attention. This needs to involve less frequent and finer-scale burning, along with the protection of some large, infrequently burnt source areas. © 2012 Ecological Society of Australia.
Palmer C.M.,Northern Territory |
Braby M.F.,the Arts and Sport |
Braby M.F.,Australian National University
Australian Journal of Entomology | Year: 2012
Croitana aestiva Edwards is one of Australia's most poorly known butterflies. Previously it was known from a total of eight specimens collected in 1966 and 1972 in the MacDonnell Ranges west of Alice Springs in central Australia. The species was not positively recorded for the next 35years; however, in February 2007 a population was rediscovered during targeted surveys. Subsequent biological studies were conducted from 2007 to 2010. A reappraisal of adult morphology show that four character states are unique to C.aestiva. Eggs are creamy-white and subcircular, with 21-29 longitudinal ribs. First-instar larvae are creamy-white, with a dark head capsule and prothoracic plate. Fourth- and fifth-instar larvae have a dark green medial band, a pale lateral band on each side of the body, and a distinct, highly setose, brown anal plate. The pupae are mainly orange-brown, darkening anteriorly, with a highly sculptured pupal cap. The larval food plant is the grass Neurachne tenuifolia (Poaceae), which is also endemic to central Australia. Shelters for all larvae and the pupa are among the leaf sheaths and stems near the base of the tussock. Adults are opportunistic feeders on a wide variety of nectar-producing plants, and are active throughout the day. Males use patrolling and perching behaviour to locate receptive females at a range of encounter sites, including the larval food plant and hilltops. Oviposition occurs during late morning, and eggs are laid on the upper surface of blades of the food plant. Comparison of the immature stages of C.aestiva with its congeners indicates many similarities in general morphology, but there are pronounced behavioural differences such as upward-orientated shelters. © 2011 The Authors. Journal compilation © 2011 Australian Entomological Society.
Braby M.F.,the Arts and Sport |
Braby M.F.,Australian National University
Biological Journal of the Linnean Society | Year: 2012
Taxonomic investigations of the Delias mysis (Fabricius, 1775) complex from northern Australia indicate two additional species in the Australian fauna: Delias aestiva Butler, 1897 stat. rev. and Delias lara (Boisduval, 1836). The latter species, which is illustrated from Australia for the first time, was until recently known under the name Delias mysis onca Fruhstorfer, 1910. Evidence from adult morphology (male genitalia), colour pattern of the adult and immature stages, behaviour, and ecology indicates substantial phenotypic divergence between D.aestiva and D.mysis. Within Australian limits, all three taxa are allopatric: D aestiva is endemic to the Top End, Northen Territory, D.mysis mysis is restricted to northern and north-eastern Queensland, whereas Deliaslara lara is known only from three specimens from the Torres Strait islands, Queensland. Delias aestiva is perhaps the most remarkable member of the complex and indeed the genus, breeding in tropical mangrove habitats in coastal estuarine areas where the larvae specialize on mature foliage of the tree Excoecaria ovalis Endl. (Euphorbiaceae). This host preference is novel given the general tendency of Delias to feed on hemiparasitic plants in the order Santalales (Loranthaceae, Santalaceae and Viscaceae). Under laboratory conditions, however, larvae successfully completed development on the mistletoe genera Amyema, Dendrophthoe and Decaisnina (all Loranthaceae) with no significant reduction in larval survival. These findings, together with phylogenetic hypotheses of the Aporiina and Delias, indicate a recent evolutionary host shift from Loranthaceae to Euphorbiaceae. The foliage of Excoecaria produces toxic latex, which is composed of a variety of secondary plant compounds, including diterpenoids, triterpenoids, alkaloids and phorbol esters. The mechanism of detoxification has not been established, although the larvae of D.aestiva are gregarious, regurgitate fluid as part of their chemical defence, and the adults are highly aposematic. Adults are seasonal, being chiefly on the wing during the cooler dry season; during the wet season, the larval food plant is seasonally deciduous and it is suspected that the butterfly undergoes pupal diapause. The cryptically coloured green pupa and tendency to pupate singly in concealed situations of D.aestiva are highly unusual traits among Delias and are hypothesized to be adaptive responses associated with pupal diapause during the wet season. The unique habitat association, novel food plant specialization, and restricted distribution of D.aestiva emphasizess the biogeographical peculiarities of northern Australia, especially patterns of historical (vicariant) differentiation between the Top End and Cape York Peninsula within the Australian Monsoon Tropics. © 2012 The Linnean Society of London.