Search for dissertations about: "David Wardle"

Found 3 swedish dissertations containing the words David Wardle.

  2. 1. Phosphorus availability and microbial respiration across biomes : from plantation forest to tundra

    Author : Camilla Esberg; Reiner Giesler; David A. Wardle; Bente J. Graae; Dan Binkley; Umeå universitet; []
    Keywords : LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; phosphorus availability; microbial bioassay; soil respiration; microbial growth rate; Hedley fractionation; soil sorption; weathered soils; boreal forest; subarctic and tundra;

    Abstract : Phosphorus is the main limiting nutrient for plant growth in large areas of the world and the availability of phosphorus to plants and microbes can be strongly affected by soil properties. Even though the phosphorus cycle has been studied extensively, much remains unknown about the key processes governing phosphorus availability in different environments. READ MORE

  4. 2. Biotic resistance in freshwater fish communities

    Author : Anna Henriksson; Göran Englund; David Wardle A.; Jun Yu; Sebastian Diehl; Donald Jackson; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; biotic resistance; freshwater fish; introductions; invasions; invasion success; invasibility; invasiveness; species richness; saturation; species identity; weighted species richness;

    Abstract : Invasions of non-native species cause problems in ecosystems worldwide, and despite the extensive effort that has been put into research about invasions, we still lack a good understanding for why some, but not other, communities resist these invasions. In this doctoral thesis I test hypotheses on biotic resistance using a large dataset of more than 1000 both failed and successful introductions of freshwater fish into Swedish lakes. READ MORE

  5. 3. Mosses as mediators of climate change : implications for tree seedling establishment in the tundra

    Author : Signe Lett; Ellen Dorrepaal; David Wardle; Marie-Charlotte Nilsson; Vigdis Vandvik; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; arctic; alpine; B. pubescens; bryophytes; competition; facilitation; mosses; P. sylvestris; precipitation changes; seedlings; traits; tree line; warming;

    Abstract : Alpine and arctic tree line expansion depends on the establishment of tree seedlings above the current tree line, which is expected to occur with climate warming. However, tree lines often fail to respond to higher temperatures. Other environmental factors are therefore likely important for tree seedling establishment. READ MORE