Upload
royal
View
41
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Varna, 14 June 2005. UNESCO Regime shifts workshop. Topological constraints on the dynamics of wasp-waist ecosystems Ferenc JORDÁN Institute of Ecology and Botany , Hungarian Academy of Sciences, V ácrátót , and Collegium Budapest, Institute for Advanced Study, Budapest, Hungary; - PowerPoint PPT Presentation
Citation preview
Topological constraints on the dynamicsof wasp-waist ecosystems
Ferenc JORDÁN
Institute of Ecology and Botany,Hungarian Academy of Sciences, Vácrátót,
andCollegium Budapest, Institute for Advanced Study,
Budapest, Hungary;
[email protected], http://falco.elte.hu/~jordanf
Varna, 14 June 2005 UNESCO Regime shifts workshop
Wasp-waistarchitecture(simplified)
B
H
B C
D E F
G
HI
J
Jordán, F., Liu, W.C. and Wyatt, T. Topological constraints on the dynamics of wasp-waist ecosystems. Journal of Marine Systems, in press.
A
Model food webs N = 10L = 12equal complexity
B C
D E F
G
HI
J
A
Wasp-waist species:
D > 3
Din = 0
Dout = 0
B C
D E F
G
HI
J
A
Wasp-waist species:
D > 3
Din = 0
Dout = 0
G
G5
G5 on G1, G3, G4, G7 and G8:direct plus indirect
G5 on G2, G9 and G10:only indirect
G5 on G5:self-regulatory effect
G5 on G6:effect on another wasp-waist
G4G3G1 G2
G6
G7 G8 G9 G10
SardineAnchovy
Shared predators
Apparent competition
SardineAnchovy
Shared prey
Exploitative competition
Marine mammals
SardineAnchovy
Trophic cascade
SardineAnchovy
Horse mackerel
Shared prey
Keystone predation
Marine mammals
SardineAnchovy
Horse mackerel
Shared predators
Shared prey
Peruvian upwelling
Rich interaction structure:network context,multispecies management
Jarre-Teichmann A. (1998). The potential role of mass balance models for themanagement of upwelling ecosystems. Ecological Applications 8, S93-S103.
Topological importance index: TI
TIi;j = kn (k;j / l
m k;l) (i;k / kn i;k)
Jordán F., Liu W-C, and Wyatt T. Topological constraints on the dynamics of wasp-waistecosystems. Journal of Marine Systems, in press.
D
CPCD = 1/DC
AA
D
BB
C C
PBA * PCB + PDA * PCD = PCA
PCD
PDA
PCB
PBA
PCB
PBA
PBA * PCB = PCA
additive multiplicative
1 2 3 4 5 6 7 8 9 10
1 0,08 0,04 0,04 0,08 0,22 0,28 0,08 0,08 0,04 0,04
2 0,08 0,05 0,03 0,08 0,13 0,37 0,08 0,08 0,05 0,05
3 0,09 0,03 0,06 0,09 0,31 0,19 0,09 0,09 0,03 0,03
4 0,08 0,04 0,04 0,08 0,22 0,28 0,08 0,08 0,04 0,04
5 0,09 0,03 0,06 0,09 0,24 0,26 0,09 0,09 0,03 0,03
6 0,08 0,05 0,03 0,08 0,18 0,32 0,08 0,08 0,05 0,05
7 0,08 0,04 0,04 0,08 0,22 0,28 0,08 0,08 0,04 0,04
8 0,08 0,04 0,04 0,08 0,22 0,28 0,08 0,08 0,04 0,04
9 0,08 0,05 0,03 0,08 0,13 0,37 0,08 0,08 0,05 0,05
10 0,08 0,05 0,03 0,08 0,13 0,37 0,08 0,08 0,05 0,05
0,83 0,42 0,41 0,83 2,03 2,97 0,83 0,83 0,42 0,42
The interaction matrix of web G for n = 8.G
Relative strength of effects spreading out from G5
Relative strength of effects reaching G5
G
0,00
1,00
2,00
3,00
4,00
5,00
6,00
1 2 3 4 5 6 7 8 9 10
species
impo
rtanc
e one
three
eight
The effect spectrum of web G for n = 1, 3 and 8.
Regime shifts:topological constraints on the sardine-anchovy interaction
web G: sardine - anchovy effects
0,000,050,100,150,200,250,300,350,40
interaction rank
stre
ngth
othersinterWW
G
Regime shifts:topological constraints on the sardine-anchovy interaction
web F: sardine - anchovy effects
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
interaction rank
stre
ngthF
Indirect vs mixed control regimes
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
1 13 25 37 49 61 73 85 97
interaction rank
stre
ngth indirect
mixed
Purely indirect is stronger in many cases than mixed (direct plus indirect)
Self-regulation
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
1 9 17 25 33 41 49 57 65 73 81 89 97
species rank
self-
regu
latio
n st
reng
th
othersWWs
Self-regulatory feedback loops are extremely strong for wasp-waist species
OverfishingIn fished down food webs the probability of mixed interction is reduced,while positive feedback increases leading to alternating states.
+
--
-
Both – and + loops Only + loops
-
InvasionRegime shift: jellyfish invades into a second wasp-waistposition and replaces anchovy – topology predicts high invadibility
Shiganova T. A. (1998). Invasion of the Black Sea by the ctenophore Mnemiopsis leidyiand recent changes in pelagic community structure. Fisheries Oceanography 7, 305-310.
33
1
3
5
4
6
2
9
8
7
1112
13
21
22
23 19
14
15
25
18
26
16
27
28
17
2930
31
32
34
Top-down, KTD
Striped bass, #33
Indirect one-step, TI1also in the KPP-1k=3 set
Bay anchovy, #22
,11 1
1
1
1tef
m
ebcd
n
cx KKK
ec
TIi;j = kn (k;j / l
m k;l) (i;k / kn i;k)
Chesapeake Bay –important fishes?
Conclusions:
• System topology (architecture) constraints dynamics
• Certain behaviours are more probable (canalised trajectory)
• Regime shifts caused biotically are more expected in wasp-waist ecosystems
• Overfishing increases this effect• Vulnerable if invader enters the wasp-
waist
Acknowledgements:
Tim WyattCSIC Instituto de Investigaciones Marinas, Vigo, Spain
Wei-chung LiuDepartment of Tropical Veterinary Medicine,University of Edinburgh, UK
Vera Vasas and Zsófi BenedekEötvös University, Budapest
The Branco Weiss Fellowship,Society in Science, ETH Zürich
The Organisers for the invitation