Is what you see what you get? Visual vs. measured assessments of vegetation condition
- Authors: Cook, Carly , Wardell-Johnson, Grant , Keatley, Marie , Gowans, Stacey , Gibson, Matthew , Westbrooke, Martin , Marshall, Dustin
- Date: 2010
- Type: Text , Journal article
- Relation: Journal of Applied Ecology Vol. 47, no. 3 (2010), p. 650-661
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- Description: 1. An important step in the conservation of biodiversity is to identify what exists, its quantity and its quality (i.e. condition). This can be a daunting task at the landscape-scale, so vegetation communities are often used as surrogates for biodiversity. Satellite imagery has improved our ability to rapidly measure vegetation parameters but the need for calibration still requires rapid and cost-effective on-ground condition assessment. Some management agencies address this need by using visual condition assessments, with unknown consequences for the different purposes of condition data. It is therefore vital to examine the comparability of visual and systematic condition assessment methods to guide their use in conservation decision making. 2. We compared visual assessments of vegetation condition with more systematic and higher resolution on-ground assessments, using a method where both assessments were made for the same quadrats. We determined both the condition parameters observers respond to when making visual assessments of condition, and the consequences of any differences for the application of these data. 3. We found that visual assessment of vegetation condition broadly represented measured assessments of the same vegetation, but that observers simplify their assessments by responding to only some of the measured condition parameters. No consistent trends were found in the parameters observers responded to across the different vegetation types sampled. 4. Synthesis and applications. We conclude that visual estimates of vegetation condition are only of sufficient resolution to replace more expensive, high-resolution assessments at a landscape-scale, when condition results are combined over multiple areas and vegetation types. Visual assessment methods potentially can provide an efficient measure of overall condition for conservation management agencies where practitioners can make assessments of condition in the course of their daily management activities - an important step forward. At smaller scales, idiosyncratic effects render visual estimates highly variable when compared with systematic condition assessments. This variability, especially among vegetation types, suggests that more systematic assessments are necessary when management decisions require higher-resolution estimates of changes in individual condition parameters, such as when measuring the success of individual management actions. These findings provide a valuable guide for selecting the most appropriate approach for the different objectives of condition assessments for biodiversity conservation.
- Description: 2003008171
Phenological studies in Australia: Potential application in historical and future climate analysis
- Authors: Keatley, Marie , Fletcher, Tim , Hudson, Irene , Ades, Peter
- Date: 2002
- Type: Text , Journal article
- Relation: International Journal of Climatology Vol. 22, no. 14 (Nov 2002), p. 1769-1780
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- Description: Phenological observations of eucalypts (Myrtaceae) were undertaken in four Australian states (New South Wales, Queensland, Victoria, and Western Australia) from the late 1920s until the early 1980s, by the respective State Forest Commissions. Unfortunately, few records have survived. For Victoria, surviving records encompass 42 forest districts, covering from less than 2 years to 42 years, and approximately 50 species. This paper concentrates on the flowering of four competing species (Eucalyptus leucoxylon, E. microcarpa, E. polyanthemos, and E. tricarpa) over 23 years (1940-62) from Maryborough, Victoria, recorded on a monthly basis by one observer over the period. This study represents one of the first attempts to utilize Australian phenological data to detect responses to climate change. There were no significant trends (P = 0.05) over time in the mean flowering commencement date. Forward stepwise regression found a significant relationship between temperature and flowering commencement in two species (E. leucoxylon: R-2 = 0.42, P < 0.01; E. polyanthemos: R-2 = 0.47, P = 0.02). Rainfall also had a significant influence on flowering commencement in E. tricarpa (R-2 = 0.60, P < 0.01), E. leucoxylon (R-2 = 0.43, P = 0.02) and E. polyanthemos (R-2 = 0.24, P < 0.01). The combination of temperature and rainfall (with temperature exerting the greatest influence), however, was significant for all species and had the most explanatory power (ranging from R-2 = 0.74 to 0.85, P < 0.01). Overall, in response to predicted increases in temperature and summer rainfall, E. leucoxylon and E. tricarpa would commence flowering later. In E. polyanthemos and E. microcarpa, increased temperature and rainfall will result in an earlier onset of flowering. Copyright (C) 2002 Royal Meteorological Society.
- Description: 2003000171
Does size matter : Tree use by translocated koalas
- Authors: Santamaria, Flavia , Keatley, Marie , Schlagloth, Rolf
- Date: 2005
- Type: Text , Journal article
- Relation: Victorian Naturalist Vol. 122, no. 1 (2005), p. 4-13
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- Description: Overbrowsing of manna gum (Eucalyptus viminalis) and, in some instances, swamp gum (E. ovata) has occurred in areas where koalas (Phascolarctos cinereus) have been translocated. A study of 30 radio-tracked translocated koalas examined tree use at three release forests in the Ballarat Vic region. Some 20 tree species were used by koalas. The results showed that koalas will use a wide variety of tree species if available and show a preference for larger trees (A).
- Description: 2003001473
The golf ball method for rapid assessment of grassland structure
- Authors: Schultz, Nick , Keatley, Marie , Antos, Mark , Wong, Nathan , Moxham, Claire , Farmilo, Brad , Morgan, John
- Date: 2017
- Type: Text , Journal article
- Relation: Ecological Management and Restoration Vol. 18, no. 2 (2017), p. 134-140
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- Description: A key task for native grassland managers is to assess when biomass reduction is necessary to maintain plant and animal diversity. This requires managers to monitor grassland structure. Parks Victoria and La Trobe University developed a method for rapid assessment of grassland structure using golf balls. Baker-Gabb et al. (Ecological Management & Restoration, 17, 2016, p235) provide an example of where the method has been used to manage grassland structure to favour an endangered bird, the Plains-wanderer (Pedionomus torquatus). In this study, we provide further critical analysis of the method using three data sets collected across different parts of Victoria that relate golf ball scores to various habitat attributes. We demonstrate how the golf ball score provides a good surrogate for key aspects of grassland structure. We show that the method does not provide a reliable surrogate for above-ground biomass or vegetation cover, although we discuss how biomass and cover are not particularly good indicators of grassland structure. We argue that elements of grassland structure may be better correlated with desired conservation outcomes (e.g. plant species diversity or the presence of a particular species) than biomass or cover alone. We discuss examples of how the golf ball method has been used, and how it can be improved. The method will be particularly useful where a link can be demonstrated between golf ball scores and desired conservation outcomes, such as in the case of the Plains-wanderer. © 2017 Ecological Society of Australia and John Wiley & Sons Australia, Ltd