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Ecologie et Dynamique des Systèmes AnthropisésFRE 3498 CNRS-UPJVwww.u-picardie.fr/edysan
Ali Almoussawi, Jonathan Lenoir, Tarek Hattab, Emilie Gallet-Moron, Carol Garzon, Ahmad Kobaissi, Guillaume Decocq
Email: [email protected]
A Multiscalar Assessment of Plant Species Richness in Small Forest Patches
Embedded in Agricultural Landscapes
OBJECTIVES
a) Relation between alpha and gamma diversity at different spatial scales
(local-regional richness relationship)
b) Effect of habitat fragmentation on the alpha-gamma relationship:
proportional sampling (type I in Cornell & Lawton) vs. community
saturation (type II in Cornell and Lawton)
METHOD
SLOPEln(SL/(SR-SL))
ln(SR)
The local-regional species richness relationship: new perspectives on the null-hypothesis (Robert C. Szava-Kovats , Martin
Zobel and Meelis Pärtel).
EXPLANATION
P-value ≥ 0.05 linear SL- SR relation
(no significance)
P-value < 0.05 curved SL- SR relation
(significance)
Significant negative slope (slope<0)
curvature to the right
Significant positive slope (slope>0)
curvature to the left
X = ln(SR)
X = SR
Y=
SL
Y=
ln
(SL
/(S
R-S
L))
9 windows
3 open fieldsOB-OC-OT (highly
isolated)15 patches of
each
3 farm landsBB-BC-BT
(fragmented)15 patches of
each
3 unfragmented lands
FB-FC-FT (fake patches)
15 patches of each
ORGANIZATION
135 Total Patches
9 WINDOWS
10 STUDIED PAIRWISE COMPARISONS IN
EACH WINDOW
9*10= 90 COMPARISONS
For every patch
Total
1000m2
100m210m2
1m2
ORGANIZATION
Table of Significance
α γ BOCAGE
slope aB
FOREST
slope aF
OPENFIELD
slope aO
BOCAGE
aB curvature
FOREST
aF curvature
OPENFIELD
aO curvature
1 10 -0.3039 0.0193 0.4405 Linear Linear Linear
1 100 -0.03557 0.09473 -1.07757 Linear Linear Linear
1 1000 -0.1023 -0.0515 0.1791 Linear Linear Linear
1* Total -0.04242 0.11218 -1.350 Linear Linear Curvilinear to the right
10 100 0.329 -0.25 0.5343 Linear Linear Linear
10 1000 0.0719 -0.4038 -0.3507 Linear Linear Linear
10* Total 0.1514 -0.2019 -1.2736 Linear Linear Curvilinear to the right
100 1000 -0.243 -0.15438 -0.5474 Linear Linear Linear
100* Total -0.1019 0.0042 -1.5859 Linear Linear Curvilinear to the right
1000* Total -0.03486 -0.09957 -2.1488 Linear Linear Curvilinear to the right
CONCLUSIONS
- Fragmentation affects the relation between local (alpha) and regional (gamma) diversity of species.
- The representation of this relationship turns from being a linear to a curvilinear pattern due to the effect of fragmentation of patches (Open-field).
- This relationship appears in cases of large difference between local and regional area.