POST-DOCTORAL POSITION OPEN in ECOLOGICAL MODELLING
Relationships between alpha, beta and gamma plant diversity of forest patches in contrasted agricultural landscapes: confronting empirical field measures to theoretical model predictions Open at the Jules Verne University of Picardy (UPJV) - Plant biodiversity Lab. Amiens city (North France, ca. 150 km north to Paris) - Prof. Guillaume DECOCQ Deadline for application: September 15th, 2008 Duration: 1 year, starting in October 2008. Requirements: - Experience in theoretical ecology: (1) local species assemblages (alpha diversity): from niche-based to neutral models of species coexistence (2) metapopulation models (3) metacommunity models: species-area curves, distribution-abundance curves. - Good knowledge of statistical modelling tools Background: By postulating ecological equivalence among species, random distribution and abundance fluctuation over time, Hubbells neutral theory has refuted niche-based explanations of species coexistence. Neutrality leads to two important predictions. First, species richness will increase proportionally to the regional species pool within an assemblage over time. Second, a divergence of species composition among local communities will occur over time due to dispersal limitations. However, dispersal between local communities can act as a homogenizing force, tending to reduce beta diversity and increase alpha diversity, and thus to saturate local communities, that is α diversity tends toward gamma diversity at equilibrium. Because of its conceptual simplicity the neutral model is currently subject of hot debate but may be a useful null model for baseline comparison to actual patterns of distribution, abundance, species composition and alpha, beta and gamma diversities. However, competitive asymmetries among species and spatial heterogeneity have to be taken into account, as well as the importance of scale on the relationships between alpha and beta diversity. Despite a significant amount of papers that propose an empirical evaluation of neutral models, few studies have provided a rigorous analysis of discrepancies between predicted and observed patterns. To date, field tests remain scarce, particularly in the context of spatially complex ecosystems evolving on long timeframes like forests. Mission: Confronting the results from empirical studies (already available) to predictions from various theoretical models; more specifically: - testing how well the results from empirical studies (field survey of plant communities in forest patches that are embedded in contrasted agricultural landscapes, comparatively to plant communities in non fragmented forests) fit niche-based and neutral models of species assemblages; - modelling spatio-temporal dynamics of populations of several target plant species at the landscape scale (metapopulations); - modelling relationships between α (intra-patch), β (inter-patches) and γ (landscape) diversity of plant communities, using metacommunity models based on species-area curves and distribution- abundance curves. CV to be sent to: Prof. Guillaume DECOCQ ([EMAIL PROTECTED]) University of Picardy Jules Verne - Plant Biodiversity Lab 1 rue des Louvels F-80037 Amiens Cedex, France. Tel/Fax: +33 (0)322 827 761.
