Trade-offs between development, culture and conservation - Willingness to pay for tropical river management among urban Australians

Australia\u27s system of tropical rivers constitutes one of the largest and least changed drainage networks in the world. However increasing demand for water in parts of Australia, along with ongoing drought, is driving pressure to develop these rivers. This paper reports the results of a choice experiment (CE) to assess the benefits of different management strategies for three tropical rivers in northern Australia: the Daly, Mitchell and Fitzroy Rivers. The CE was carried out using a survey mailed to Australian urban populations. The results showed that 90% of Australians were willing to pay a once-off payment for the management of tropical rivers. Respondents who had visited or lived near the rivers were willing to pay more for cultural, recreational and environmental services than those who had not. Respondents classed as \u27developers\u27, who made up only 4% of the 684 respondents, considered a substantial income from irrigated agriculture as important. Unlike \u27environmentalists\u27 and \u27neutrals\u27, \u27developers\u27 were unwilling to pay for high quality recreational fishing or for having floodplains in good environmental condition. All groups, however, were willing to pay for high cultural values

Chemical abundances in spiral and irregular galaxies. O and N abundances derived from global emission--line spectra

The validity of oxygen and nitrogen abundances derived from the global emission-line spectra of galaxies via the P-method has been investigated using a collection of published spectra of individual HII regions in irregular and spiral galaxies. The conclusions of Kobulnicky, Kennicutt & Pizagno (1999) that global emission-line spectra can reliably indicate the chemical properties of galaxies has been confirmed. It has been shown that the comparison of the global spectrum of a galaxy with a collection of spectra of individual HII regions can be used to distinguish high and low metallicity objects and to estimate accurate chemical abundances in a galaxy. The oxygen and nitrogen abundances in samples of UV-selected and normal nearby galaxies have been determined. It has been found that the UV-selected galaxies occupy the same area in the N/O -- O/H diagram as individual HII regions in nearby galaxies. Finally, we show that intermediate-redshift galaxies systematically deviate from the metallicity -- luminosity trend of local galaxies.Comment: 15 pages, 17 figures, accepted for publication in Astronomy and Astrophysic

Starbursts and Star Clusters in the Ultraviolet

Hubble Space Telescope ultraviolet (UV) images of nine starburst galaxies reveal them to be highly irregular, even after excluding compact sources (clusters and resolved stars). Most (7/9) are found to have a similar intrinsic effective surface brightnesses, suggesting that a negative feedback mechanism is setting an upper limit to the star formation rate per unit area. All starbursts in our sample contain UV bright star clusters indicating that cluster formation is an important mode of star formation in starbursts. On average about 20% of the UV luminosity comes from these clusters. The brightest clusters, or super star clusters (SSC), are preferentially found at the very heart of starbursts. The size of the nearest SSCs are consistent with those of Galactic globular clusters. The luminosity function of SSCs is well represented by a power law with a slope alpha ~ -2. There is a strong correlation between the far infrared excess and the UV spectral slope. The correlation is well modeled by a geometry where much of their dust is in a foreground screen near to the starburst, but not by a geometry of well mixed stars and dust.Comment: 47 pages, text only, LaTeX with aaspp.sty (version 3.0), compressed postscript figures available at ftp://eta.pha.jhu.edu/RecentPublications/meurer

Condition index monitoring supports conservation priorities for the protection of threatened grass-finch populations

Conservation agencies are often faced with the difficult task of prioritizing what recovery actions receive support. With thenumber of species under threat of decline growing globally, research that informs conservation priorities is greatly needed. Therelative vulnerability of cryptic or nomadic species is often uncertain, because populations are difficult to monitor and localpopulations often seem stable in the short term. This uncertainty can lead to inaction when populations are in need of protection.We tested the feasibility of using differences in condition indices as an indication of population vulnerability to decline forrelated threatened Australian finch sub-species. The Gouldian finch represents a relatively well-studied endangered species,which has a seasonal and site-specific pattern of condition index variation that differs from the closely related non-declininglong-tailed finch. We used Gouldian and long-tailed finch condition variation as a model to compare with lesser studied, threatenedstar and black-throated finches. We compared body condition (fat and muscle scores), haematocrit and stress levels (corticosterone) among populations, seasons and years to determine whether lesser studied finch populations matched the modelof an endangered species or a non-declining species. While vulnerable finch populations often had lower muscle and higher fatand corticosterone concentrations during moult (seasonal pattern similar to Gouldian finches), haematocrit values did not differamong populations in a predictable way. Star and black-throated finch populations, which were predicted to be vulnerableto decline, showed evidence of poor condition during moult, supporting their status as vulnerable. Our findings highlight howmeasures of condition can provide insight into the relative vulnerability of animal and plant populations to decline and willallow the prioritization of efforts towards the populations most likely to be in jeopardy of extinctio