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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. . Wiley and International Association for Vegetation Science are collaborating with JSTOR to digitize, preserve and extend access to Journal of Vegetation Science. Abstract. The importance of the shape of a species response curve to an environmental gradient is reviewed. The implications for vegetation theory, ordination methods, species as indicators of environmental conditions, predicting species distribution from surveys and simulation models of climatic impact on vegetation are examined. A P-function V = k (xa)a. (bx)7 is used to model species response curves using generalized linear modelling (GLM). Two hypotheses are tested;(1) that response curves differ significantly from a unimodal symmetric (Gaussian) shape and (2) that the direction of skew is a function of species position along the gradient. Nine eucalypt species are modelled using GLM with a f/function fitted for mean annual temperature. Six other environmental variables and factors are considered in fitting the statistical models; mean annual rainfall, mean monthly solar radiation, topographic position, lithological type, nutrient index and rainfall seasonality.All nine species are significantly skewed in response to temperature. The direction of skew is positive when a species optimum temperature falls below 11.5 ?C and negative for species with optimum above. These results indicate that current vegetation analyses which require the modelling of species response curves, or assumptions about the shape of the response, require reassessment.

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Abstract:In many parts of the world, urban planning has a renewed focus on addressing the multiple challenges associated with population growth and climate change. Focused on local needs and priorities, these planning processes are raising tensions between more compact and dense urban form to reduce energy use and associated emissions and the provision of urban green infrastructure for ecosystem services and climate adaptation. In this study, we investigated the spatial distribution of green infrastructure at the neighbourhood scale in Sydney, Australia and examined how a mix of landscape types (pavement, bare soil/dry grass, green grass, and tree cover) affect temperature variation in three important locations for urban residents-around the home, in the roads and footpaths where people walk, and in parkland areas. Considering that residential and parkland areas contribute to the majority of green space in Sydney, it is important to understand how changes in landscape mix within these three neighbourhood areas will affect local temperature for urban residents. For residential houses, it was found that the percentage of tree canopy cover around the house had a significant negative relationship (p = 0.002) with surface temperatures of rooftops where greater tree cover led to lower rooftop temperatures. In streetscapes, both the percentage of tree cover (p < 0.0001) and the percentage of green grass (p < 0.0001) within the road segment had a significant negative relationship with the surface temperature of the road pavement. In the parks, the percentage of pavement (p < 0.0001) and the percentage of bare soil/dry grass (p < 0.0001) showed a significantly positive trend with land surface temperatures where greater land cover in the form of pavement and bare soil/dry grass led to higher temperatures. Collectively, these findings highlight the importance of promoting or reducing certain landscape covers depending on the land use type in order to maximise the cooling potential of green infrastructure.