1) the Full Citation Reference for the Study

Scarlett Arana March 31, 2011 GEO 4300 ENVIRONMENTAL BIOGEOGRAPHY

Literature Summary #5

1) The full citation reference for the study Paquette, A. and Messier, C. (2011), The effect of biodiversity on tree productivity: from temperate to boreal forests. Global Ecology and Biogeography, 20: 170–180.

Alain Paquette is works for Center for Forest Research from the University of Québec at Montréal, and Messier is from Center for Forest Research in Montréal, QC Canada.

2) The research problem or question (1 or 2 sentences) Is tree productivity positively related to diversity? Does the effect of diversity increase in less productive forests? What metric of diversity better relates to tree productivity?

3) The general background knowledge leading up to this study (2 sentences) Growing interests in evaluating the role of biodiversity in order to promote ecosystem function, services, resilience, biodiversity ecosystem in order to complementarily of the effects and to select of particular function traits such as sampling effect. This lead to experimental work has led to the proposal of mechanisms such as niche complimentarily, however, few attempts have been made to confirm these in natural systems, especially in forests.

4) The methods used by the investigators (1 or 2 sentences) Investigators studied over 12,000 permanent forests in order to plot and study the regressions used to identify the best explanatory variables for tree productivity. Climatic, environmental, density and biodiversity variables were studied in a structural equation model in order to links paths between variables and making structural equation modeling in order to explore causal networks.

5) The results of the study (2 sentences and one figure or table) The result of the study demonstrated differences between the two forest biomes investigated. The effects of biodiversity on productivity may therefore be less important in temperate forests growing on rich deep soils under more favorable climates where competitive exclusion is the most probable outcome of species interactions concluding that complementarily effects are more important to ecosystem processes in harsh climates, whereas competitive exclusions tend to favorable few dominant, highly productive species in more productive conditions.

(see table below) 6) What are the weaknesses of the study The study indicated that data used for the study was limited to traits such as leaf economics, reproductive and morphological descriptors and not enough data on belowground traits could not be found. Research however does raise questions on natural forest ecosystems and adds understanding of the nature of plant relationships and where competitive exclusions are most likely to occur under more/less favorable habitats condition.

7) What we learned new from the study (2 sentences) The main objective of the paper is to inform the reader of effect of biodiversity on tree productivity focusing on temperate to boreal forests and to investigate the nature of the relationship between biodiversity and ecosystem functioning over a large forest extent in North-Eastern North America. I learn that there is a significant effect of biodiversity on tree productivity due to climatic and environmental conditions.