Developing an effective conservation and sustainable use economy: two Arnhem Land case studies<br />

SummaryThis is the final report for the research project &lsquo;Developing an effective conservation and sustainable use economy in Arnhem Land: Options for payment for environmental services&rsquo;. The research was undertaken at the Centre for Aboriginal Economic Policy Research (CAEPR) at the Australian National University (ANU). The Tropical Rivers and Coastal Knowledge (TRaCK) research hub funded the research. This report provides a preliminary assessment of the management needs and costs for two Indigenous Protected Areas (IPAs) in Arnhem Land, as well as a preliminary cost-benefit analysis (CBA) of the social benefits and costs associated with the management of the protected areas. The project commenced in July 2009 and was completed in March 2011.This report is aimed at helping decision-makers in communities, businesses, nongovernment organisations and government agencies consider payment for environmental services alongside continued public funding to support economic development in remote Indigenous communities. Crucially, this report highlights the need for better information and alternative economic perspectives in relation to the capacity of payment for environmental services to support the regional economy of Arnhem Land. This information is critical to addressing both opportunities for and barriers to the development of an effective conservation and sustainable use economy in this region and beyond.The research was carried out in collaboration with two Indigenous Ranger groups in Arnhem Land, the Djelk Rangers (Bawinanga Aboriginal Corporation) in Maningrida and the Dhimurru Rangers (Dhimurru Aboriginal Corporation) in Nhulunbuy. The two groups manage the Djelk IPA and the Dhimurru IPA respectively. The Djelk IPA was declared in 2009. It extends over 6,732 km2 stretching from the Central Arnhem Plateau to the Arafura Sea in the Arnhem Coast sub-bioregion ARC-2. The Djelk IPA has outstanding environmental and cultural values for the diversity of its landscapes and languages, and the wealth of community assemblages and species. The Dhimurru IPA was established in 2000. It covers around 920 km2 of land and 90 km2 of adjacent marine areas in the Gove Peninsula. The IPA contains areas of important cultural and environmental values, hosting a significant representation of Australia\u27s Arnhem Coast sub-bioregion ARC-3. Both IPA&rsquo;s are generally considered to be in near pristine condition.The two IPAs face quite different environmental management problems. The Djelk Rangers&rsquo; priorities focus on land and sea management including fire, weed and feral animal control and coastal surveillance. Among the most important issues for the Dhimurru IPA is managing the growing demand for the recreational uses of its environmental and cultural resources. Recreational activities could damage sensitive ecological systems, spread weeds and invasive ants through vehicles movement, disturb native flora and fauna, and damage cultural and sacred sites. The bauxite mine and processing plant adjacent to the Dhimurru IPA also have a serious impact on the integrity of the natural environment and cultural landscape.Both the Djelk and the Dhimurru rangers finance their management activities mainly through public funding. Djelk&rsquo;s revenues are split between government grants (78%) and fee-for-service earnings (22%). The Djelk Rangers use these finances to employ over 35 Indigenous rangers as well as to cover the operational costs of a range of activities including weed and feral animal control, fire management, and coastal patrols. Four activities&mdash;weed control, fire management, customs patrols, and marine debris patrols&mdash; generate 85 per cent of Djelk&rsquo;s total expenditure. The major source of Dhimurru&rsquo;s revenues is public funding (69%), and it is supplemented by Dhimurru&rsquo;s own generated income (20.5%), private contributions (9.2%) and fee-for-service income (1.6%). Dhimurru\u27s activities have interconnected goals: people management, environmental monitoring, conservation and restoration, and heritage and cultural protection. People management includes issuing general and special access permits to non-Indigenous visitors, checking permit compliance, camp site maintenance, fencing, and rubbish pickup. It accounts for over 74 per cent of Dhimurru&rsquo;s total expenditure. Weed control and crocodile management account for another 17 per cent of the Dhimurru&rsquo;s expenses.Public funding and fee-for-service revenues are the cost to society of this provision of environmental services through Indigenous ranger organisations. Both funding streams originate largely from institutional responsibilities of government. A variety ofCommonwealth programs such as Working on Country (WoC) and Indigenous Protected Areas (IPAs) are based on this principle. Here the government outsources some of its responsibility to protect the environment by contracting local Indigenous rangers to provide environmental services. In return, Indigenous rangers are required to provide some measure of accountability for their work through management plans, progress reports and financial reports. However, the compensation for this service is calculated on the basis of the government&rsquo;s accounting rule for granting funding and on what the ranger organisations estimate it will cost for them to deliver the service. They are not based on estimates of the benefits that the rangers&rsquo; activities generate for the Australian public.Lack of data, methodological limitations, and a short timeframe, severely restricted the quantitative assessment of the demand for environmental services. Therefore it is not possible to&nbsp; contrast the benefits of Indigenous provision of environmental services in the two IPAs with either&nbsp; the social costs or the organisations&rsquo; private expenditure. As a result, the data presented here is&nbsp; not sufficient to demonstrate in economic terms that the benefits of environmental service&nbsp; provision within the IPAs justify their social cost. Similarly, it was not possible to assess the&nbsp; feasibility of financing Indigenous provision of environmental services in the IPAs on the basis of he benefits it generates at the local and national levels. Further research is necessary to collect more data on such issues over longer time periods. A robust analysis of the costs and benefits of Indigenous provision of environmental services needs to account for temporal and spatial variability, and take into account the fluctuations in environmental, economic and social&nbsp; conditions. Priority should also be given to the collection of basic ecological data. This is necessary to assess the effectiveness of management practices in reaching environmental outcomes

Sardinia Radio Telescope wide-band spectral-polarimetric observations of the galaxy cluster 3C 129

We present new observations of the galaxy cluster 3C 129 obtained with the Sardinia Radio Telescope in the frequency range 6000-7200 MHz, with the aim to image the large-angular-scale emission at high-frequency of the radio sources located in this cluster of galaxies. The data were acquired using the recently-commissioned ROACH2-based backend to produce full-Stokes image cubes of an area of 1 deg x 1 deg centered on the radio source 3C 129. We modeled and deconvolved the telescope beam pattern from the data. We also measured the instrumental polarization beam patterns to correct the polarization images for off-axis instrumental polarization. Total intensity images at an angular resolution of 2.9 arcmin were obtained for the tailed radio galaxy 3C 129 and for 13 more sources in the field, including 3C 129.1 at the galaxy cluster center. These data were used, in combination with literature data at lower frequencies, to derive the variation of the synchrotron spectrum of 3C 129 along the tail of the radio source. If the magnetic field is at the equipartition value, we showed that the lifetimes of radiating electrons result in a radiative age for 3C 129 of t_syn = 267 +/- 26 Myrs. Assuming a linear projected length of 488 kpc for the tail, we deduced that 3C 129 is moving supersonically with a Mach number of M=v_gal/c_s=1.47. Linearly polarized emission was clearly detected for both 3C 129 and 3C 129.1. The linear polarization measured for 3C 129 reaches levels as high as 70% in the faintest region of the source where the magnetic field is aligned with the direction of the tail.Comment: 19 pages, 17 figures, accepted for publication in MNRA

Imaging of SNR IC443 and W44 with the Sardinia Radio Telescope at 1.5 GHz and 7 GHz

Observations of supernova remnants (SNRs) are a powerful tool for investigating the later stages of stellar evolution, the properties of the ambient interstellar medium, and the physics of particle acceleration and shocks. For a fraction of SNRs, multi-wavelength coverage from radio to ultra high-energies has been provided, constraining their contributions to the production of Galactic cosmic rays. Although radio emission is the most common identifier of SNRs and a prime probe for refining models, high-resolution images at frequencies above 5 GHz are surprisingly lacking, even for bright and well-known SNRs such as IC443 and W44. In the frameworks of the Astronomical Validation and Early Science Program with the 64-m single-dish Sardinia Radio Telescope, we provided, for the first time, single-dish deep imaging at 7 GHz of the IC443 and W44 complexes coupled with spatially-resolved spectra in the 1.5-7 GHz frequency range. Our images were obtained through on-the-fly mapping techniques, providing antenna beam oversampling and resulting in accurate continuum flux density measurements. The integrated flux densities associated with IC443 are S_1.5GHz = 134 +/- 4 Jy and S_7GHz = 67 +/- 3 Jy. For W44, we measured total flux densities of S_1.5GHz = 214 +/- 6 Jy and S_7GHz = 94 +/- 4 Jy. Spectral index maps provide evidence of a wide physical parameter scatter among different SNR regions: a flat spectrum is observed from the brightest SNR regions at the shock, while steeper spectral indices (up to 0.7) are observed in fainter cooling regions, disentangling in this way different populations and spectra of radio/gamma-ray-emitting electrons in these SNRs.Comment: 13 pages, 9 figures, accepted for publication to MNRAS on 18 May 201

Duty cycle of the radio galaxy B2 0258+35

Radio loud Active Galactic Nuclei are episodic in nature, cycling through periods of activity and quiescence. In this work we investigate the duty cycle of the radio galaxy B2~0258+35, which was previously suggested to be a restarted radio galaxy based on its morphology. The radio source consists of a pair of kpc-scale jets embedded in two large-scale lobes (~240 kpc) with relaxed shape and very low surface brightness, which resemble remnants of a past AGN activity. We have combined new LOFAR data at 145 MHz and new SRT data at 6600 MHz with available WSRT data at 1400 MHz to investigate the spectral properties of the outer lobes and derive their age. Interestingly, the spectrum of both the outer Northern and Southern lobes is not ultra-steep as expected for an old ageing plasma with spectral index values equal to $\rm \alpha_{1400}^{145}=0.48\pm0.11$ and $\rm \alpha_{6600}^{1400}=0.69\pm0.20$ in the outer Northern lobe, and $\rm \alpha_{1400}^{145}=0.73\pm0.07$ in the outer Southern lobe. Moreover, despite the wide frequency coverage available for the outer Northern lobe (145-6600~MHz), we do not identify a significant spectral curvature (SPC$\simeq$0.2$\pm0.2$). While mechanisms such as in-situ particle reacceleration, mixing or compression can temporarily play a role in preventing the spectrum from steepening, in no case seem the outer lobes to be compatible with being very old remnants of past activity as previously suggested (with age $\gtrsim$ 80 Myr). We conclude that either the large-scale lobes are still fuelled by the nuclear engine or the jets have switched off no more than a few tens of Myr ago. Our study shows the importance of combining morphological and spectral properties to reliably classify the evolutionary stage of low surface brightness, diffuse emission that low frequency observations are revealing around a growing number of radio sources.Comment: 13 pages, 4 figures, 6 tables, A&A accepte

Methods for detection and analysis of weak radio sources with single-dish radio telescopes

The detection of mJy/sub-mJy point sources is a significant challenge for single-dish radio telescopes. Detection or upper limits on the faint afterglow from GRBs or other sources at cosmological distances are important means of constraining the source modeling. Using the Sardinia Radio Telescope (SRT), we compare the sensitivity and robustness of three methods applied to the detection of faint radio sources from raster maps around a known source position: the smart quick-look method, the source extraction method (typical of high-energy astronomy), and the fit with a 2-D Gaussian. We developed a Python code specific for the analysis of point-like radio sources applied to the SRT C-band (6.9 GHz) observations of both undetected sources (GRB afterglows of 181201A and 190114C) and the detected Galactic X-ray binary GRS 1915+105. Our comparative analysis of the different detection methods made extensive use of simulations as a useful complement to actual radio observations. The best method for the SRT data analysis is the fit with a 2-D Gaussian, as it pushes down the sensitivity limits of single-dish observations -- with respect to more traditional techniques -- to ~ 1.8 mJy, improving by ~ 40 % compared with the initial value. This analysis shows that -- especially for faint sources -- good maps of the scanned region pre- or post-outburst are essential.Comment: 22 pages, 11 figures, 3 tables, pre-print of an article published in Experimental Astronomy; v2: updated abstract and reference

New high-frequency radio observations of the Cygnus Loop supernova remnant with the Italian radio telescopes

Supernova remnants (SNRs) represent a powerful laboratory to study the Cosmic-Ray acceleration processes at the shocks, and their relation to the properties of the circumstellar medium. With the aim of studying the high-frequency radio emission and investigating the energy distribution of accelerated electrons and the magnetic field conditions, we performed single-dish observations of the large and complex Cygnus Loop SNR from 7.0 to 24.8 GHz with the Medicina and the Sardinia Radio Telescope, focusing on the northern filament (NGC 6992) and the southern shell. Both regions show a spectrum well fitted by a power-law function ($S\propto\nu^{-\alpha}$), with spectral index $\alpha=0.45\pm0.05$ for NGC 6992 and $\alpha=0.49\pm0.01$ for the southern shell and without any indication of a spectral break. The spectra are significantly flatter than the whole Cygnus Loop spectrum ($\alpha=0.54\pm0.01$), suggesting a departure from the plain shock acceleration mechanisms, which for NGC 6992 could be related to the ongoing transition towards a radiative shock. We model the integrated spectrum of the whole SNR considering the evolution of the maximum energy and magnetic field amplification. Through the radio spectral parameters, we infer a magnetic field at the shock of 10 $\mu$G. This value is compatible with a pure adiabatic compression of the interstellar magnetic field, suggesting that the amplification process is currently inefficient.Comment: 19 pages, 13 figure