The presentation of the CESAB group DIVGRASS at the 2016 french ecology conference in the FRB-CESAB session "Using a treasury of knowledge to tackle complex ecological questions." Presenter: Pierre Denelle

1. Macroecology of species pools:
insights from network theory
Application to French meadows
Pierre Denelle
Centre d’Ecologie Fonctionnelle et
Evolutive
DIVGRASS consortium

3. = species pool

4. Synthesis center (CESAB)
Eric Garnier, Jens Kattge, Bernard Amiaud, Nicolas Viovy, Sophie Gachet, Sylvain Diquélou, Jean Olivier, Guilhem Debarros, Pierre
Cellier, Jessy Loranger, Cyrille Violle, Philippe Choler (PI), Benjamin Borgy, François Munoz, Alexis Mikolajczak
Missing: Claudy Jolivet, Sandra Lavorel & Servane Lemauviel
DIVGRASS Project
Plant Functional Diversity of Grasslands (2011-2013)

5. Data combination
CLIMATE & DERIVED
Precipitation, min/mean/max
Temperature, ETP…
SOIL CHARACTERISTICS
Clay/Sand/Silt, pH, Depth,
Water content, CaCO3,…
LAND COVER
> 90 000 Relevés
> 4 000 species
COMMUNITY DATA
PLANT TRAITS
Specific Leaf
Area (SLA), Leaf
Dry Matter Content
(LDMC), Seed
Mass,…
> 3000 species
7 traits
+ lat/lon

6. DivGrass plots
> 90,000 relevés
From (Violle et al., 2015)
> 4000 species

7. How to identify
the large-scale drivers of
biodiversity
in species pools?

8. Site-species matrices seen differently: connecting nodes together
with links.
Classification of species and sites at the same time.
Understanding large-scale co-occurrence patterns
through the lens of network theory
Co-occurrence patterns analysed at a regional scale.

9. Network-based species pool results:

10. Spatial extent

11. Environmental identity
Two main PCA axes:
Hydric and temperature gradient
Acidophile vs calcareous

12. Environmental identity

13. Environmental identity

14. Functional identity
Leaf nitrogen content (mg[N]/g)
Leaf phosphorus content (mg[P]/g)

15. Conclusion
Bipartite network of ecological communities, with species and sites
as nodes, occurrences as links.
Topological heterogeneity in link distribution represents non-random
co-occurrence patterns.
Large-scale modules describe regional species pools with specific
functional and biogeographic properties.
= species pool

16. Perspectives
To go further:
- Hierarchical modularity analysis
- Ecological specialization
= species pool

17. Thanks for your attention
Thanks to the Divgrass consortium
pierre.denelle@cefe.cnrs.fr
francois.munoz@cirad.fr
cyrille.violle@cefe.cnrs.fr