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  • 1
    Electronic Resource
    Electronic Resource
    Characteristics of Australia's rangelands and key design issues for monitoring biodiversity (2004)
    Oxford, UK : Blackwell Science, Ltd
    Austral ecology 29 (2004), S. 0 
    Details
    ISSN: 1442-9993
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract  We explored the key issues that are most likely to influence any set of guiding principles for developing biodiversity monitoring programmes in Australia's rangelands. We defined the Australian rangelands and came up with an overview of their climate extremes, land-use pressures and biodiversity loss, and then focussed on issues underpinning the design phase of any monitoring programme. Using Noss's 1990 framework of compositional, structural and functional attributes of biodiversity and its new revisions by others, we showed how the elusive, abstract concept of biodiversity can be used to identify many measurable attributes that can form a minimum and necessary set of indicators for any biodiversity monitoring task. We then described the steps in the monitoring process, with a particular focus on the reasons for monitoring biodiversity as they strongly influence the selection of indicators. We concluded by compiling a table of key issues as background information for developing guiding principles (Table 4). The list is by no means an exhaustive list for the design phase but it does indicate that considerable attention needs to be given to this phase when developing monitoring programmes. We have intentionally not addressed the equally important issues associated with the planning and delivery phases of developing a monitoring programme, as Wallace et al. and Watson and Novelly cover these in their papers in the present issue of Austral Ecology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1442-9993.2004.01360.x
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  • 2
    Electronic Resource
    Electronic Resource
    Response of vertebrates to fenceline contrasts in grazing intensity in semi-arid woodlands of eastern Australia (2003)
    Oxford, UK : Blackwell Science Pty
    Austral ecology 28 (2003), S. 0 
    Details
    ISSN: 1442-9993
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract  Changes in the abundance, species richness and assemblage composition of vertebrates due to grazing by domestic stock were investigated in the semi-arid woodlands of eastern Australia. Analyses were based on the differences found at 10 fenceline contrast sites. Two species of amphibians, 22 species of reptiles and two species of small mammal were captured in pit traps during the surveys. Kangaroos (red and eastern grey), sheep, goats and 66 species of birds were recorded along line transects. Analyses revealed that abundance of diurnal reptiles and species richness of diurnal reptiles and birds were significantly lower on heavily grazed sites than they were on lightly grazed sites. At a local scale, the gecko, Gehyra variegata, was more abundant where grazing was heavier, while Diplodactylus conspicillatus, Diplodactylus steindachneri and Rhynchoedura ornata responded to variables indirectly related to grazing intensity (kangaroo density, sheep and goat dung mass and sheep density, respectively). Birds more commonly sighted on lightly grazed areas than heavily grazed areas were the apostlebird, brown treecreeper, crested bellbird, grey butcherbird, hooded robin, jacky winter, little woodswallow, Australian magpie-lark, mulga parrot, splendid wren, white-browed treecreeper and yellow-rumped thornbill. Birds more commonly sighted on heavily grazed areas than on lightly grazed areas were the Australian raven and chestnut-crowned babbler. Most variation in species composition between sites was due to spatial separation and no regional-level indicator species of grazing were evident. A combination of direct grazing-related changes (e.g. loss of ground cover) and indirect effects of the pastoral industry (e.g. introduction of artificial sources of water) lead to changes in fauna at different scales of analysis across regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1442-9993.2003.01259.x
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  • 3
    Electronic Resource
    Electronic Resource
    Monitoring ecological indicators of rangeland functional integrity and their relation to biodiversity at local to regional scales (2004)
    Oxford, UK : Blackwell Science, Ltd
    Austral ecology 29 (2004), S. 0 
    Details
    ISSN: 1442-9993
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract  Functional integrity is the intactness of soil and native vegetation patterns and the processes that maintain these patterns. In Australia's rangelands, the integrity of these patterns and processes have been modified by clearing, grazing and fire. Intuitively, biodiversity should be strongly related to functional integrity; that is, landscapes with high functional integrity should maintain biodiversity, and altered, less functional landscapes may lose some biodiversity, defined here as the variety and abundance of the plants, animals and microorganisms of concern. Simple indicators of biodiversity and functional integrity are needed that can be monitored at a range of scales, from fine to coarse. In the present paper, we use examples, primarily from published work on Australia's rangeland, to document that at finer patch and hillslope scales several indicators of landscape functional integrity have been identified. These indicators, based on the quantity and quality of vegetation patches and interpatch zones, are related to biodiversity. For example, a decrease in the cover and width (quantity) and condition (quality) of vegetation patches, and an increase in bare soil (quantity of interpatch) near cattle watering points in a paddock are significantly related to declines in plant and grasshopper diversity. These vegetation patch-cover and bare-soil indicators have been monitored traditionally by field-based methods, but new high-resolution, remote-sensing imagery can be used in specific rangeland areas for this fine-scale monitoring. At intermediate paddock and small watershed scales, indicators that can be derived from medium-resolution remote-sensing are also needed for efficient monitoring of rangeland condition (i.e. functional integrity) and biodiversity. For example, 30–100-m-pixel Landsat imagery has been used to assess the condition of rangelands along grazing gradients extending from watering-points. The variety and abundance of key taxa have been related to these gradients (the Biograze project). At still larger region and catchment scales, indicators of rangeland functional integrity can also be monitored by coarse-resolution remote-sensing and related to biodiversity. For example, the extent and greenness (condition) of different regional landscapes have been monitored with 1-km-pixel satellite imagery. This regional information becomes more valuable when it indicates differences as a result of land management. Finally, we discuss potential future developments that could improve proposed indicators of landscape functional integrity and biodiversity, thereby improving our ability to monitor rangelands effectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1442-9993.2004.01349.x
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  • 4
    Electronic Resource
    Electronic Resource
    Trapping intensities for sampling ants in Australian rangelands (2004)
    Oxford, UK : Blackwell Science, Ltd
    Austral ecology 29 (2004), S. 0 
    Details
    ISSN: 1442-9993
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract  I investigated the relationship between species richness and composition of ant faunas, and sampling intensity in two regions with different long-term histories of grazing intensity in mulga (Acacia aneura) woodlands in northern New South Wales. There were two aims: (i) to examine the relationship between sampling intensity and species richness and composition; and (ii) to explore the differences in ant assemblages from two regions of markedly different grazing intensity when sampled at different intensities (i.e. when a higher proportion of the local ant fauna were collected). Ants were sampled in pit traps (120-mm diameter) at densities of two, four, six and nine pits per 100 m2. Each sampling-intensity treatment was replicated three times within each region. Pit traps filled with preservative were opened for 3 days. Species richness was higher with each successive increase in sampling intensity but was not different between regions for a given trapping intensity. There was no obvious asymptote of the curve relating trapping intensity to cumulative species richness suggesting that even greater trap densities than those used in the present study would be needed to collect most of the species of ants using a patch of ground over a few days. Spatial replication of a low-intensity sampling design did not capture as many species as one higher-intensity sampling array with the same total number of pit traps. This result can be explained by aggressive numerically dominant species of ants monopolizing access to a greater proportion of the traps in low-density arrays. Ordination reveals that regions and sampling-intensity treatments could be discriminated and that differences between regions with different grazing histories were less apparent with high-intensity sampling arrays than they were with low-intensity sampling arrays. This suggests that differences between locations in space (or potentially samples in time) could be exaggerated by incomplete sampling of the patch-scale fauna. Comparison of the present study with other studies suggests that most studies to date have used sampling intensities that would not give a thorough assessment of the patch-scale ground-dwelling fauna if sampled only by pit traps. The implications of the results for programmes of ant monitoring in rangelands are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1442-9993.2004.01351.x
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  • 5
    Electronic Resource
    Electronic Resource
    Temporal variation in diets and trophic partitioning by coexisting lizards (Ctenotus: Scincidae) in central Australia (1991)
    Springer
    Oecologia 85 (1991), S. 553-561 
    Details
    ISSN: 1432-1939
    Keywords: Diets ; Lizards ; Arid-zone ; Sympatry ; Ctenotus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The diets of five syntopic species of Ctenotus were examined over a two-year period on a 60 ha spinifex grassland site in central Australia. The aims of the study were to test predictions that termites were an important part of the food web for syntopic Ctenotus in spinifex grasslands, and to examine seasonal changes in prey use and dietary overlap between the species. Environmental conditions during the first season of the study were dry resulting in generally low invertebrate abundance. In contrast the second season was relatively moist and overall invertebrate abundance was higher than in the first season. Diets of five species of Ctenotus contained a range of terrestrial prey although one species (C. pantherinus) was relatively termite-specialized at all times. Dietary overlap at the ordinal level between the species was generally higher during dry periods when prey abundance was low, and higher for species-pairs that were similar in body size. During the driest period of the study most species of Ctenotus ate a high proportion of termite prey which accounted for the high dietary overlap. However, each species of Ctenotus consumed different genera or foraging guilds of termites. The results suggest that most of these lizards were opportunistic in their selection of prey but that during dry periods when prey are scarce, termites may play a significant role in supporting a high α-diversity of Ctenotus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323768
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  • 6
    Electronic Resource
    Electronic Resource
    Pollination ecology of Yucca elata (1993)
    Springer
    Oecologia 93 (1993), S. 512-517 
    Details
    ISSN: 1432-1939
    Keywords: Yucca elata ; Tegeticula yuccasella ; Mutualism ; Pollination ; Fruit set
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pollination biology of a population of 250 Yucca elata (Liliaceae) plants was studied in southern New Mexico. Yucca elata and the prodoxid yucca moth Tegeticula yuccasella have a mutualistic association that is essential for the successful sexual reproduction of both species. However, a wide range of other invertebrate species visit flowers during the day and at night. Our aim was to quantify the role of yucca moths and other invertebrate visitors in pollination and fruit set, using manipulative field experiments. Inflorescences were bagged during the day or night (N=12 inflorescences) to restrict flower visitors to either nocturnal or diurnal groups. Yucca moths were active exclusively nocturnally during the flowering period and thus did not visit inflorescences that were unbagged during the day. None of the 4022 flowers exposed only to diurnal visitors set fruit, whereas 4.6% of the 4974 flowers exposed only to nocturnal visitors (including yucca moths) produced mature fruit. The proportion of flowers producing fruit in the latter treatment was not significantly different from unbagged control inflorescences. In a series of experimental manipulations we also determined that: (1) flowers opened at dusk and were open for two days on average, but were only receptive to pollen on the first night of opening; (2) pollen must be pushed down the stigmatic tube to affect pollination; and (3) most plants require out-cross pollination to produce fruit. The combination of these results strongly suggests that yucca moths are the only species affecting pollination in Y. elata, and that if another species was to affect pollination, it would be a rare event.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00328959
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