Alternative equilibria and Alternative equilibria and resilience in Arctic aquatic resilience in Arctic aquatic

systemssystems

Arctic Frontiers ATP 2011 Arctic Frontiers ATP 2011 TromsøTromsø

Primicerio R, Amundsen P-A, Aschan M, Knudsen R, Planque B, Varpe Ø

BarEcoReBarEcoRe ATPATP

Alternative equilibria in the Arctic

Outline• Bistability and resilience• Mechanisms of bistability• Managing metastable

systems

Bistability and resilience

• Alternative equilibria in Arctic aquatic systems

• Management challenges of tipping points

Alternative equilibria in the Arctic

Bistability and resilience• Alternative equilibria in

Arctic aquatic systems• Management challenges of

tipping points Lake Takvatn

2009 TREE2009 TREE

Alternative equilibria in the Arctic

Bistability and resilience• Lake Takvatn

Culling experiment - removed 31 tons (660000 individuals) of Arctic charr in the period 1984 to 1989

Alternative equilibria in the Arctic

2007 Science2007 Science

Bistability and resilience

• Lake Takvatn

Alternative equilibria in the Arctic

Bistability and resilience

• Lake Takvatn

Alternative equilibria in the Arctic

Tipping Tipping pointpoint

Bistability and resilience

• Lake Takvatn

Alternative equilibria in the Arctic

Tipping Tipping pointpoint

Mechanisms of bistability

• Lake Takvatn

Alternative equilibria in the Arctic

Mechanisms of bistability

• Lake Takvatn

0 500 1500 2500

0.0

1.0

2.0

3.0

Time

Abu

ndan

ce

Alternative equilibria in the Arctic

Mechanisms of bistability

• Lake Takvatn

0 500 1500 2500

0.0

1.0

2.0

3.0

Time

Abu

ndan

ce

Alternative equilibria in the Arctic

Tipping Tipping pointpoint

Mechanisms of bistability

• Lake Takvatn

0 500 1500 2500

0.0

1.0

2.0

3.0

Time

Abu

ndan

ce

Alternative equilibria in the Arctic

Tipping Tipping pointpoint

Mechanisms of bistability

• Lake Takvatn

0 500 1500 2500

0.0

1.0

2.0

3.0

Time

Abu

ndan

ce

Juveniles

Ad

ults

Alternative equilibria in the Arctic

Mechanisms of bistability

• Lake Takvatn

0 500 1500 2500

0.0

1.0

2.0

3.0

Time

Abu

ndan

ce

Alternative equilibria in the Arctic

Mechanisms of bistability

• Lake Takvatn

Alternative equilibria in the Arctic

Mechanisms of bistability

• Lake Takvatn

Alternative equilibria in the Arctic

Mechanisms of bistability

• Lake Takvatn

Alternative equilibria in the Arctic

Mechanisms of bistability

• Lake Takvatn

Alternative equilibria in the Arctic

Mechanisms of bistability

• Lake Takvatn

Alternative equilibria in the Arctic

Mechanisms of bistability

• Lake Takvatn

Alternative equilibria in the Arctic

Mechanisms of bistability

• Emergent Allee effect

Alternative equilibria in the Arctic

Mechanisms of bistability

• Lake Takvatn

Alternative equilibria in the Arctic

Bistability and resilience• Regime shifts – variable vs

parameter change• Resilience – ecological vs

engineering

Fishing induced evolution in salmonidsMaturation schedules• Arctic charr in Lake Takvatn

Fish removal

Suspended harvest

1984 1986 1988 1990 1992 1994 1996

20

25

30

35

Cohort

Length

(cm

)