The boundaries between community types, which are rich sources of spatial heterogeneity, are related to a wide variety of biotic and abiotic edge effects. The prevalence of boundaries in modern landscapes emphasizes the need to understand their ecological function. In order to understand boundary function, improved knowledge is needed regarding how environmental factors and vegetation vary under human influence and across multiple scales. Measuring and understanding multi-scale influences is a significant challenge in many fields. This doctoral dissertation research project focuses on evaluating the relative influence of aspect (local scale), management regime (landscape scale), and atmospheric deposition (regional scale) on the character of forest-field edges in southern Sweden. More intensive management, especially increased fertilizer application, and greater atmospheric deposition have increased soil acidity and nitrogen availability in northern Europe's forest and grassland communities, which generally are quite nutrient-poor. These trends have led to marked changes in species composition and declines in plant diversity. Such interactions have likely been intensified across forest-field edges because of their ecological function as 'sinks' (areas where matter has accumulated). This project study will evaluate the general hypothesis that the biotic edge is directly related to abiotic controls and conditions that vary with respect to location and management regime. Specific objectives of this study are to determine abiotic and biotic variation across forest-field edges, to assess relationships between abiotic and biotic variables, and to identify edge characteristics and functions that differ with respect to location at the local, landscape, and regional scale. The study will be conducted in the southwest and east-central regions of Sweden. Locations of sampling sites reflect the regional gradient from high to low deposition. In each region, replicate sites will be located under each of two management regimes: traditional (non-fertilized) and intensively managed (fertilized) meadows. For each management regime, replicate sites will be sampled across a southwest-facing and a northeast-facing edge. Field research will consist of sampling vegetation and environmental characteristics (such as air and soil temperature, relative humidity, soil pH, and soil moisture tension) along forest-field edge gradients. Soil samples will be collected at a sub-set of sites for laboratory analyses.
The results of this project will have both theoretical and management implications. Despite its often-cited importance, multi-scale complexity across edges is not well understood. The project will explore a method for measuring and quantitatively examining the relative influence of processes operating at different scales across landscape boundaries. Results therefore will provide scientists and resource managers with important insights regarding the relationship between regional- and local-scale processes in a culturally fragmented landscape. In addition, by examining change in microclimate, soil conditions, and vegetation across forest-field edges under varying rates of acidic deposition and fertilization, a better understanding can be gained of how boundaries function under human-induced environmental change. Such environmental changes may have a direct effect on forestry, agriculture, water quality, and biodiversity. Findings from this study therefore can be used in land-use planning and environmental policy formation. The project should provide empirical support for the nature of forest-field boundaries in northern Europe as well as provide information about anthropogenic effects at multiple scales. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.
