BIOL3007 Lecture Notes - Lecture 12: Plant Community, Introduced Species, Meta-Analysis
29 Nov 2018
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Document Summary
Use each other as cues to find food. Plant community example: moose have negative effect of willow and aspen (they eat them) and an indirect positive effect on spruce (they don"t eat it). Two hypotheses: 1) moose decrease nutrient recycling: preferences of willow and aspen to benefit spruce, leads to spruce decaying slowly and minimising nutrient recycling. 2) moose increase nutrient recycling: convert leaves to scats which are broken down easily and increase nutrient recycling. Results show that absence of moose in high browsing areas leads to higher mineralization. Consistent with hypothesis 1, due to their preferences. But, in order to confirm this they must show a shift in communities otherwise mechanism hasn"t been established. Nutrient recycling example: looked at grazers and fenced and unfenced areas. The presence of grazers over two years increases nutrient gain (opposite to moose system). Scats seem to outweigh results seen with moose. Meta analysis shows 45 replicated field experiments and 35 unreplicated field experiments.
