Sue V. Briggs

Relating wetland inundation to river flow using Landsat TM data

Satellite imagery has been used in many studies that seek to relate river flow to floodplain inundation. However, on rivers with moderately to highly variable daily flows it is difficult to establish a reliable relationship between river stage and area of floodplain inundation. This is because the rapid downstream movement of the flood peak results in the area of maximum inundation at any time being spatially restricted. This study presents a method that accounts for rapid variation in daily discharge using before-flood and after-flood sequences of Landsat Thematic Mapper (TM) imagery in reference to a predefined wetland vector coverage. This procedure establishes a relationship between wetland inundation and river discharge. It also reduces errors of commission arising from: the retention of water on the floodplain from previous floods; the filling of wetlands from rainfall and other non-channel sources; and pixel mis-classification.

Nature grows in straight lines—or does she? What are the consequences of the mismatch between human-imposed linear boundaries and ecosystem boundaries? An Australian example

Abstract Sustainability in agricultural landscapes means that the use and management of ecological potential does not reduce its capacity to meet society’s future environmental, social and economic needs. Using this description of sustainability, Australian agricultural systems are far from sustainable at present. Removal of vast areas of native vegetation and the introduction of inappropriate agricultural systems have resulted in extensive loss of native biota, loss of productive agricultural land and decline in rural society. These degrading trends will continue to worsen unless Australian society intervenes on a broad scale. For example, to stop water tables from rising with attendant salination of soil, it has been estimated that over 30 billion perennial trees and shrubs will need to be planted. How does a society generate the will and ability to tackle environmental problems at this scale when its community and institutional boundaries do not reflect ecological reality? This paper discusses these issues and concludes with a 10-point plan to guide development of an approach to sustainable landscapes.

Condition of fenced and unfenced remnant vegetation in inland catchments in south-eastern Australia

Considerable areas of remnant native vegetation have been fenced in the last decade to manage grazing by domestic stock. This study investigated vegetation condition in comparative fenced and unfenced remnant vegetation in the mid–upper Murrumbidgee and Lachlan catchments in south-eastern Australia. Native species richness, native groundcover and overstorey regeneration were higher at fenced than at unfenced sites. Area of bare ground was lower at fenced sites. Exotic groundcover did not differ between fenced and unfenced sites. Native species richness was higher at sites fenced for longer and with no stock grazing; neither native nor exotic groundcover at fenced sites was related to time since fencing or stock grazing pressure. Some tree species regenerated at both fenced and unfenced sites (Blakely’s red gum, Eucalyptus blakelyi; tumbledown gum, E. dealbata, long-leaved box, E. goniocalyx; red stringbark, E. macrorhyncha), some regenerated at few fenced and few unfenced sites (white box, E. albens; yellow box, E. melliodora) and some regenerated at fenced sites but not at unfenced sites (grey box, E. microcarpa; mugga ironbark, E. sideroxylon; white cypress pine, Callitris glaucophylla). Although less robust than pre- and postfencing monitoring, the comparisons reported here provide a logistically feasible and relatively inexpensive assessment of effects of the sizeable public investment in fencing on vegetation condition.

Impacts of salinity on biodiversity—clear understanding or muddy confusion?

Dryland salinity has been known for several decades in eastern Australia. Its causes have been known for at least five decades. Why did it take so long for the problem to be officially recognised? Why is it taking so long for impacts of dryland salinity on terrestrial biodiversity to be investigated in eastern Australia? To answer these questions we delve back into human history and then move forwards to modern times. Historically, salt has connotations of punishment, money, status and love. Today, salt ignites powerful emotions in humans in modern institutions. Controlling the salinity agenda enhances status and provides resources. Impacts of salinity on biodiversity are often ignored when powerful groups with little interest in biodiversity compete for dominance of the salinity agenda. After discussing these factors, the paper presents information about impacts of dryland salinity on terrestrial biodiversity in eastern Australia. The limited research conducted shows that dryland salinity threatens vegetation communities that are already depleted from extensive clearing. Native ground species of plants in salinised woodlands are replaced by exotics and weeds. Trees die. The paper concludes with recommendations for future actions to enhance understanding and management of impacts of dryland salinity on terrestrial biodiversity in eastern Australia.

Educational and Conservation Value of Whale Watching

Many people support whale watching on the basis that it enhances people’s appreciation and awareness of the whales they are viewing and can lead to the protection of the species and of the environment generally. Because whale watching can directly impact on whales’ behavior it is important that whale watching is beneficial for people’s understanding of whales and for the conservation of whales. This article examines the educational and conservation value of the whale-watching experiences currently offered in New South Wales, Australia. The current education provided lacks structure, there are no clear conservation objectives, and there is limited addition to knowledge and conservation behaviors of whale watchers in the long term. Through improvement of the education provided during whale-watching experiences, it is argued that the whale-watching industry can become a more sustainable form of wildlife tourism and provide conservation benefits for whales and other forms of biodiversity.

Biodiversity benefits of alley farming with old man saltbush in central western New South Wales

Agricultural production systems that also provide opportunities to conserve biodiversity will be a crucial component of integrated and sustainable land use in mixed farming landscapes and should be considered and evaluated. Alley farming is an innovative farming system that aims to increase farm profitability while also enhancing environmental outcomes. Alley farming incorporates belts of woody perennial plants such as trees or shrubs, interspersed with alleys of conventionally rotated cropping and livestock grazing land. In the present study, we assessed the impacts on terrestrial biodiversity of alley farming with the native perennial chenopod shrub old man saltbush (Atriplex nummularia Lindl.) in central western New South Wales. Terrestrial biodiversity conservation status was assessed by site surveys conducted in spring 2005, 2006 and 2007 at 15 old man salt bush alley farming sites (OMSB), 15 conventionally managed sites and three native woodland remnants in and around the Condobolin Agricultural Research and Advisory Station in the central western plains of New South Wales. Biodiversity surveys included an assessment of ‘site condition’ – a metric of biodiversity conservation status at the site scale based on measurement of 10 habitat and vegetation condition attributes, compared against benchmark values for the appropriate native ecosystems with relatively little recent anthropogenic modification. Bird surveys were also conducted to assess the diversity and abundance of birds in OMSB, conventional and remnant woodland sites in four functional response groups. Site condition was significantly higher at remnant woodland sites than at conventional farming and OMSB alley farming sites. Remnant woodland sites had greater native overstorey cover and native ground cover of forbs, more trees with hollows, presence of at least some overstorey regeneration and the presence of fallen logs. Site condition was also significantly higher at OMSB sites than at conventional sites and increased significantly across 3 years. By the third year after establishment, OMSB sites had higher native plant species richness and native mid-storey cover than did conventionally farmed sites. These attributes increased markedly over time at the OMSB sites whereas they did not increase at conventional or remnant woodland sites. Native grasses and forbs established under and around the saltbush plants, indicating that OMSB alley plantings can provide habitat for a wide range of native plant species, enhancing biodiversity values of these areas through improved structure and composition. Improved habitat condition at the OMSB sites after 3 years did not lead to a significantly higher diversity or to a higher overall abundance of birds at the OMSB than at conventional sites. Furthermore, diversity and abundance of birds at both OMSB and conventional sites remained significantly below those of remnant woodland sites. Some decliner bird species were observed using OMSB sites, but not conventional sites. Old man saltbush alley farming can provide direct on-site benefits for native biodiversity by improving the structure, function and composition of vegetation at the site or paddock scale. If proposed as a replacement to conventional crop–pasture rotation, OMSB alley farming can enhance biodiversity conservation values, and where production benefits are likely, could play an important role in the integration of production and conservation as a synergistic ‘win–win’ system in mixed farming enterprises.

Structures of bird communities in woodland remnants in central New South Wales, Australia

The overall aim of this study was to investigate structures of bird communities in remnants of fragmented box/cypress pine woodlands in central New South Wales, Australia, to guide habitat rehabilitation. The aims of the study were to: (1) determine how bird densities and species richness varied with remnant category; (2) determine how ranked densities of bird species varied by feeding group with remnant category; and (3) provide information on structures of bird communities in box/cypress pine woodlands to guide restoration. Structures of bird communities varied with remnant category. Large remnants had the most species whereas medium-sized and small remnants in low condition had the fewest. Bird densities increased with decreasing remnant area although densities did not differ significantly between remnant categories. Ranked bird densities varied between remnant categories, with relatively even distributions in large remnants in high condition, and uneven distributions in small remnants in low condition. Densities of small insectivores were much lower in small, low-condition remnants than in large, high-condition remnants. Densities of generalists such as noisy miner and galah showed the reverse pattern. The structures of bird communities in large remnants in good condition provide a reference state for assessing recovery of bird communities.

Do tour boats affect fur seals at Montague Island, New South Wales?

) and tour boats at Montague Island were investigated between November 1997 and November 1998. The fur seals were in four haul-out sites, which are referred to here as colonies. The study was instigated by the manage-ment requirement of the National Parks and Wildlife Service of New South Wales to determine effects of disturbance from tour boats on the fur seal colonies. At each of 84 inspections, distance between the boat and the colony was measured and seal behavior (or response) was recorded 11 times at 15-second intervals as the boat moved toward the seals. This period of 2.5 minutes was approximately the time tour boats stayed at a colony. Behavior of the fur seals ashore was recorded in four catego-ries of increasing disturbance from “Resting” to “Many moving.” From analyses using multinomial models, the probability of observing a given response by the fur seals and the pattern of the responses as a function of distance from the colony were both infl uenced by the colony under observation. In general, fur seals’ responses were signifi cantly correlated with distance between the study boat and the colony, and with the size of the colony (i.e., number of fur seals visible ashore). In all cases, the probability of the colony remaining in the “Resting” category decreased as the distance between the colony and the study boat decreased. Similarly the probability of the colony showing the maximum response (“Many moving”) increased as the distance decreased. The probability of New Zealand fur seals “Resting” was higher than for Australian fur seals. Tour boats approaching the colonies had a relatively small effect on the fur seals; few or none of them ran to the sea. Based on results from this study, we recommended that the minimum approach distance of tour boats to the fur seal colonies at Montague Island should be 40 m; other recommendations involved how tour boats approach the fur seal colonies. The former has been gazetted as a government regulation and the other recommendations have been incorporated into the license conditions for the tour boats operators.Key words: Fur seals; Tour boats; Wildlife tourism; Wildlife interactions

Science-policy interface: Scientific input limited

SERIOUS CONFUSION SURROUNDS THE ACCIDENT AT FUKUSHIMA DAIICHI NUCLEAR POWER Plant with regard to the amount of permissible radiation exposure, particularly in children (“Fukushima revives the low-dose debate,” D. Normile, News Focus, 20 May, p. 908; “Citizens fi nd radiation far from Fukushima,” D. Normile, News & Analysis, 17 June, p. 1368). The primary reason for this confusion is the lack of scientifi c evidence (1). On 29 April, Osako Toshiso, Cabinet Advisor and a professor at University of Tokyo who specializes in radiation safety, offered a tearful resignation. He claimed that the 20-mSv limit on annual radiation exposure for elementary school playground use set by the government was too high, and recommended that it should be lowered to 1 mSv/year. The government says that these standards are based on those of the International Commission on Radiological Protection (2). These may be suitable for adults, but there is insuffi cient evidence to argue that the same standards apply to children. It is now necessary to initiate a large-scale cohort study of childhood thyroid cancer in the Fukushima region. This study would register all children in the affected region; periodically and accurately measure their internal and external radiation exposure; and follow the children for more than 10 years. This would mark the most important scientifi c study that Fukushima can now offer to the people of the world. This study would augment the lessons learned from Chernobyl. Although some middle-term (~10 years) and middle-scale studies have been published on Chernobyl (3–6), most recovery projects lacked economic support (7), and the subtle health effects of low-level radiation exposure have yet to be determined. A long-term and large-scale follow-up study of the Fukushima accident can provide fi rm and reliable evidence for low-dose effects of radiation exposure on thyroid cancer in children. Given the current confusion and disorder, it would be diffi cult for Japanese researchers and the Japanese government to execute such a study singlehandedly (8). However, they should not have to organize the effort alone. The risk of childhood exposure to radiation is a real one for people living in any region of the world. It is time to organize an international joint research team supported by countries worldwide to uncover lessons to be learned from Fukushima for the sake of future humanity.

Assessing ground cover at patch and hillslope scale in semi-arid woody vegetation and pasture using fused Quickbird data

Abstract The amount and distribution of vegetation and ground cover are important factors that influence resource transfer (e.g. runoff, sediment) in patterned semi-arid landscapes. Identifying and describing these features in detail is an essential part of measuring and understanding ecohydrological processes at hillslope scales that can then be applied at broader scales. The aim of this study was to develop a comprehensive methodology to map ground cover using high resolution Quickbird imagery in woody and non-woody (pasture) vegetation. The specific goals were to: (1) investigate the use of several techniques of image fusion, namely principal components analysis (PCA), Brovey transform, modified intensity–hue–saturation (MIHS) and wavelet transform to increase the spatial detail of multispectral Quickbird data; (2) evaluate the performance of the red and near-infra-red bands (NIR), the difference vegetation index (DVI), and the normalised difference vegetation index (NDVI) in estimating ground cover, and (3) map and assess spatial and temporal changes in ground cover at hillslope scale using the most appropriate method or combination of methods. Estimates of ground cover from the imagery were compared with a subset of observed ground cover estimates to determine map accuracy. The MIHS algorithm produced images that best preserved spectral and spatial integrity, while the red band fused with the panchromatic band produced the most accurate ground cover maps. The patch size of the ground cover beneath canopies was similar to canopy size, and percent ground cover (mainly litter) increased with canopy size. Ground cover was mapped with relative accuracies of 84% in the woody vegetation and 86% in the pasture. From 2008 to 2009, ground cover increased from 55% to 65% in the woody vegetation and from 40% to 45% in the pasture. These ground cover maps can be used to explore the spatial ecohydrological interactions between areas of different ground cover at hillslope scale with application to management at broader scales.