P. Lavelle1,2, E. Velasquez3, F. Dubs1, V. Gond4, L. Celini1, J. Mathieu1, C. Rouland1, M. Harry1
METHODS
OBJECTIVES : Conversion of forest to
1. Macrofauna communities
agroecosystems in Amazonia deeply affects
the provision of soil ecosystem services, - 1 hand sorted monolith (25x25x30cm) at each point (TSBF method)
through mechanisms that still need to be - Identification of morphospecies based on specific taxonomical traits for each group.
explored in detail. 2. Macro aggregation and other soil morphological features
The aim of this study were: - Hand sorting of macroaggregates >0.5 cm according to their biogenic or physical
1. To show that deforestation affects soil origin and other items (roots, leaves, twigs etc..) (Velasquez et al., 2006)
macroaggregation through changes in 3. Landscape composition and structure
communities of soil ecosystem engineers - Constitution of raster maps based on satellite SPOT imagery; extraction of 35
(macrofauna); landscape metrics with FRAGSTAT ©
2. To identify the scale at which these
4.
4 Statistical methods : PCA and Co inertia analyses Permutation tests on groups (ADE4,
analyses. (ADE4
effects are produced: plot ( ff
ff d d l (effect of land use
fl d
Thioulouze et al., 1996).
practices) or landscape (effect of
composition and organization of the
Primary
landscape. Intensive Amerindian shifting
and exploited
Market gardening agriculture
FOREST
STUDY SITES: 2
5
14 4
4
15 2
3
6
4 19
In the coastal plain of French Guiana 2
2
•Three landscape windows 1 Km2
19 13
9 57
representing three levels of intensification
of landuse 55 57
52
Oligochaeta
I Termites
•16 points in each window located every
Ants
Landscape effect Coleo a
200m on a regular grid (except for the Coleo l
intensive market gardening)
I FOREST
2
P< 0.026
FALLOW CROPS
Dictyoptera
Diplura
Diptera l
Chilopoda
Diplopoda
Macroinvertebrate
13 2
4 13 3 2 Araneidae
3 34
6 4 29 Ot.Arachnida
communities (%)
3 2 I Isopoda
11 4 Enchytraeidae
2
change with landscape
Gasteropda
5
or landuse units.
7
28
63 15 35
Land Use effect
d ff
P< 0.04
RESULTS:
Macrofauna: - Dominance of termites, earthworms and ants (ecosystem engineers)
- Significant effects at landscape and plot (land use) scale (I)
_ Species richness affected by landuse, slthough in different ways
according to taxa: Coleoptera ans Ants favoured; termites not (II).
Morphology: - Significant separation according to landscape (p<0.05) and land use
p gy g p g p p
(p<0.01)
Significant covariations : among macrofauna and landuse (II), macrofauna and soil
morphology (III)
Macroinvertebrate species richness Macroinvertebrate communities
covaries with landscape composition covary with soil morphology
Inhabited areas
Localization of sampling windows and points
II DERM
10
LHY
35 32
III
F2(25.70%)
DIP l
a
34 31 Fragmented , heterogenous r
PSE
TERMITES Dominance crop systems
7
28
LCO 33
29 ARACOLEO
a F1(35.29%)
ANTS ENCH ISO
27
21
n
Intact
30
Ecosystem
36
OPI SCOR PUP c
SR b
Primary forest ARA
F1: 47% g
engineers
LDER 5 22 DIC
16 HEM 26 23 24 m
COLEO l GAS
DIPLO
Biogenic
13
DPL ISO 18 E
25 19
CH LDI 6
20 1
k ANT
ORT
14 12
4
8 DP 2 3
11 17 h CHIL D
TER aggregates
15
P<0.05 EWM i
9 ARAC
GAS
OTH Fragmented P<0.035
Primary Forest COLEOPTERA F
DIPLU
P<0.035
F2: 18%
CONCLUSIONS:
Changes in Amazonian landscapes significantly affect macro invertebrates communities
ACKNOWLEDGEMENTS: This work was although in different ways according to taxonomic groups. These changes are in turn
supported by the Ecosystemes Tropicaux related to changes in soil aggregation and morphology.
program of french Ministery of Environment; Significant effects are observed at the plot and landscape level, suggesting that
M. Harry was the coordinator management of soil biodiversity and associated ecosystem services needs to be done
at both scales.
(1) IRD/Universités de Paris VI et XII, UMR 137 BIOSOL, Bondy, France; (2) CIAT, Cali, Colombia; (3) Universidad Nacional de Colombia, Palmira, Valle, Colombia;
(4) CIRAD, UPR 36, Montpellier, France