Browsing by Author "Ladd, B"
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- ItemEffect of two types of tree guards (with and without weed control) on tree seedling establishment(Ecological Society of Australia, 2010-04-01) Ladd, B; Larsen, JR; Bonser, SPThere are many potential problems that can limit the success of revegetation efforts (Close & Davidson 2002; Close et al. 2007), many products available for revegetation, and little independent research on the efficacy of those products. For example tree guards are commonly used to establish native woody plants in ecological restoration projects yet the effectiveness of tree guards in promoting seedling establishment is uncertain (Lai & Wong 2005; Close et al. 2007). Tree guards may protect seedlings from vertebrate herbivores, and/or protect seedlings from desiccating hot wind and/or frost (Corr 2003; Gould 2005). In Aldinga, South Australia the summers are hot and dry and it is possible that tree guards could aggravate this heat stress (Close et al. 2007). However, due to the Mediterranean climate, winters are cold and tree guards may be beneficial because they limit seedling exposure to cold stress during the early establishment phase. Here we present the results of a trial in which we evaluated the microclimate amelioration effect of two types of tree guard, with and without weed control, on seedling establishment in Pink Gum (Eucalyptus fasciculosa) in South Australia. © 2010, Ecological Society of Australia
- ItemTowards a physical description of habitat: quantifying environmental adversity (abiotic stress) in temperate forest and woodland ecosystems(Wiley-Blackwell, 2009-09) Ladd, B; Bonser, SP; Peri, PL; Larsen, JR; Laffan, SW; Pepper, DA; Cendón, DI1. Our aim was to develop a quantitative proxy for environmental adversity (abiotic stress) in temperate Eucalyptus and Nothofagus forest and woodland ecosystems. 2. Samples and measurements were collected at 42 sites across a rainfall gradient in southern Australia, an elevation gradient in south-eastern Australia, and a longitudinal transect (temperature gradient) in Patagonia, Argentina. 3. We compared the ability of (a) abiotic variables (14 soil and 21 climatic variables) and (b) the stable carbon isotope (δ13C) values of soil organic matter (SOM), to predict variation in leaf area index (LAI; a forest productivity variable). 4. The δ13C of SOM (soil aggregates) explained more variation (57%) in LAI than multivariate statistical models that integrated information on many abiotic variables. W* (a climatic water balance model) was also a powerful predictor variable, explaining 37% of the variability in LAI. 5. Synthesis. The stable carbon isotopic signature of soil aggregates is a powerful explanatory variable that may help us to quantify environmental adversity (abiotic stress) in temperate forest and woodland ecosystems. © 2009, Wiley-Blackwell. The definitive version is available at www3.interscience.wiley.com