Food web and landscape
approaches to aquatic conservation
M. Jake Vander Zanden
Department of Zoology & Center for Limnology
Drivers of aquatic ecosystem change
Invasive species
Harvest
Agricultural pollution
Climate change
Outline
Food web
Addressing questions at broader spatial
and temporal scale (landscape)
Conservation
Application of science to
environmental management
Stable isotope
food web
studies
-Prevention (invasive species, nutrient pollution)
-Restoration (Great Lakes)
-Preservation (Mongolia)
Applications to basic
research questions
-Importance of benthic production in lakes
-Land-lake linkages
Outline
Food web
Addressing questions at broader spatial
and temporal scale (landscape)
Conservation
Application of science to
environmental management
Stable isotope
food web
studies
-Prevention (invasive species, nutrient pollution)
-Restoration (Great Lakes)
-Preservation (Mongolia)
Applications to basic
research questions
-Importance of benthic production in lakes
-Land-lake linkages
Food webs
• Food web represents predator-prey (trophic)
relationships
• Value of a food web perspective in
understanding species dynamics, ecosystem
management, restoration, conservation
Food webs
Many different views
of food webs!!
Figure 1. A food web of the North Atlantic
From Yodzis (1996)
Figure 2. Another food web of the
North Atlantic From Yodzis (1996)
Approach to quantifying food webs:
stable isotopes
Valuable ecological information from biological tissues
d15N (15N/14N) - 3.4‰ ± 0.4 enrichment per trophic level
Indicator of consumer trophic position
ORGANISM
Top predator
Planktivore
Zooplankton
Phytoplankton
d15N
10.2 ‰
6.8 ‰
3.4 ‰
0‰
Approach to quantifying food webs:
stable isotopes
d13C (13C/12C) - little enrichment per trophic level
Benthic vs. pelagic energy sources
piscivore
planktivorous fish
benthivorous fish
zooplankton
zoobenthos
phytoplankton
benthic algae
-30 ‰
-25 ‰
-20 ‰
Use of carbon and nitrogen stable
isotopes
d15N
Trophic niche space
Primary consumers
Primary producers
Offshore/pelagic
d13C
Onshore/benthic
Food web consequences of biological
invasions
Predatory fishes spreading
rapidly into new lakes
Smallmouth bass
(Micropterus dolomieu)
Rock bass
(Ambloplites rupestris)
Minnow populations in Canadian
lakes - bass versus no bass
8
Minnow
species richness
n = 9 lakes
6
4
2
Minnow catch rate
(fish/trap/day)
0
5
n = 9 lakes
4
3
2
1
none
captured
0
From Vander Zanden et al. 1999 Nature
No bass
Bass
Quantify food web shift
following bass
introduction
Negative impacts on
native lake trout
populations
From Vander Zanden et al. 1999 Nature
Outline
Food web studies
Addressing questions at broader spatial
and temporal scale (landscape)
Application of science to
environmental management
Stable isotope
food web
studies
Prevention (invasive species, nutrient pollution)
Restoration (Great Lakes)
Preservation (Mongolia)
Applications to basic
research questions
Importance of benthic production in lakes
Land-lake linkages
Smart Prevention: conceptual model to identify
‘vulnerable’ lakes
Vander Zanden et al. 2004. Ecol. Appl. 14: 132-148
13
Smart prevention of invasive
species in Wisconsin
Suite of invaders:
rainbow smelt
rusty crayfish
zebra mussel
spiny water flea
round goby
Chinese mystery snail
Eurasian watermilfoil
14
Where will round
goby invade next?
42% (1,369 km)
identified as suitable
44% (8,878 km)
identified as suitable
Kornis and Vander Zanden in press CJFAS
Rainbow smelt model application to
Wisconsin
• > 5,000 Wisconsin lakes
• 26 support smelt
• 553 can support smelt (10%
of Wisconsin lakes)
• Wisconsin is ~5% saturated
with smelt
Mercado-Silva et al. 2006 Cons. Biol. 20: 1740-1749
Red = vulnerable lakes
Dam invaders: Are impoundments more
vulnerable to invasion?
son, P.T, J.D. Olden & M.J. Vander Zanden 2008. Front. Ecol. Environ.
Impoundments
are
Impoundments
areover-invaded
over-invaded
80
Percentage Invaded
N=648
70
Natural Lakes
Impoundments
N=464
60
N=80
50
40
N=331
30
N=73
20
10
0
Spiny Water
Flea
Zebra
Mussel
Rainbow
Smelt
Rusty
Crayfish
Eurasian
Milfoil
Invader
Johnson, P.T, J.D. Olden & M.J. Vander Zanden 2008. Front. Ecol. Environ.
Smart prevention of invasive species
Ongoing research on the spread and impacts of
seven invasive species
Tools for managers to assess lake suitability
A broader management approach for guiding the
allocation of prevention efforts on a complex
landscape with a suite of invaders
Integrating the ecology and economics of aquatic
invasives
Outline
Food web studies
Addressing questions at broader spatial
and temporal scale (landscape)
Application of science to
environmental management
Stable isotope
food web
studies
Prevention (invasive species, nutrient pollution)
Restoration (Great Lakes)
Preservation (Mongolia)
Applications to basic
research questions
Importance of benthic production in lakes
Land-lake linkages
Prevention of diffuse agricultural
pollution
• Agricultural runoff is leading
source of nitrogen, phosphorus,
sediment pollution to rivers and
streams
• Improved land use practices –
riparian buffers
before
Photo by Dick Schultz
after
Photo by Dick Schultz
Prevention of diffuse agricultural
pollution
Voluntary programs have poor
track record
WI revising non-point
regulations –> creation of
Wisconsin Buffer Initiative
(WBI)
Majority of pollution derived
from a small portion of the
landscape
Target hotspots
Diebel et al. 2009 Env. Man
Improvement index for
maximum sediment reduction
Diebel et al. 2010 CJFAS
Prioritization within WBI watersheds
GIS-based analysis to
identify local hotspots with
high potential for nutrient
inputs to streams
Outline
Food web studies
Addressing questions at broader spatial
and temporal scale (landscape)
Application of science to
environmental management
Stable isotope
food web
studies
Prevention (invasive species, nutrient pollution)
Restoration (Great Lakes)
Preservation (Mongolia)
Applications to basic
research questions
Importance of benthic production in lakes
Land-lake linkages
Laurentian Great Lakes – evaluating food web
change and restoration potential
• Extirpation of deepwater cisco
community
• What have been the long-term food
web change resulting from species
introductions?
• Implications for restoration and
reintroduction
Stable isotope analysis of museum-archived
specimens
Schmidt et al. 2008 Ecology
5.0
4.6
Trophic position
Take-home messages:
1909-1929
4.8
4.4
4.2
4.0
LT
3.8
3.6
3.4
KY
BL
BFSN
DW LJ
3.2
SJ
LH
LW
3.0
2.8
-28
-27
-26
-25
-24
-23
-22
-21
-20
-19
-18
d13C
5.0
1975-2002
4.8
4.6
Trophic position
Red = deepwater ciscoes
Blue = shallow-water ciscoes
Yellow = Lake trout
Light blue = non-natives
4.4
LT
4.2
4.0
SL
3.8
CO
CH
3.6
3.4
3.2
BL
LH
RS
3.0
LW
AW
2.8
-28
-27
-26
-25
-24
-23
d C
13
-22
-21
-20
-19
-18
5.0
Take-home messages:
1909-1929
4.8
4.6
Trophic position
Red = deepwater ciscoes
Blue = shallow-water ciscoes
Yellow = Lake trout
Light blue = non-natives
1) Lake trout shifted to pelagic, feed
more on non-native rainbow smelt
and alewives
4.4
4.2
4.0
LT
3.8
3.6
3.4
KY
BL
BFSN
DW LJ
3.2
SJ
LH
LW
3.0
2.8
-28
-27
-26
-25
-24
-23
-22
-21
-20
-19
-18
d13C
5.0
1975-2002
4.8
Trophic position
4.6
4.4
LT
4.2
4.0
SL
3.8
CO
CH
3.6
3.4
3.2
BL
LH
RS
3.0
LW
AW
2.8
-28
-27
-26
-25
-24
-23
d C
13
-22
-21
-20
-19
-18
5.0
Take-home messages:
1909-1929
4.8
4.6
Trophic position
Red = deepwater ciscoes
Blue = shallow-water ciscoes
Yellow = Lake trout
Light blue = non-natives
1) Lake trout shifted to pelagic, feed
more on non-native rainbow smelt
and alewives
4.4
4.2
4.0
LT
3.8
3.6
3.4
KY
BL
BFSN
DW LJ
3.2
SJ
LH
LW
3.0
2.8
-28
-27
-26
-25
-24
-23
-22
-21
-19
-18
d13C
5.0
1975-2002
4.8
4.6
Trophic position
2) Deepwater cisco niche space
shrinks due to extirpations
-20
4.4
LT
4.2
4.0
SL
3.8
CO
CH
3.6
3.4
3.2
BL
LH
RS
3.0
LW
AW
2.8
-28
-27
-26
-25
-24
-23
d C
13
-22
-21
-20
-19
-18
5.0
Take-home messages:
1909-1929
4.8
4.6
Trophic position
Red = deepwater ciscoes
Blue = shallow-water ciscoes
Yellow = Lake trout
Light blue = non-natives
1) Lake trout shifted to pelagic, feed
more on non-native rainbow smelt
and alewives
4.4
4.2
4.0
LT
3.8
3.6
3.4
KY
BL
BFSN
DW LJ
3.2
SJ
LH
LW
3.0
2.8
-28
-27
-26
-25
-24
-23
-22
-21
-18
1975-2002
4.8
4.6
Trophic position
3) Exotics distinct from natives, but
now occupy niche space similar to
historical natives
-19
d13C
5.0
2) Deepwater cisco niche space
shrinks due to extirpations
-20
4.4
LT
4.2
4.0
SL
3.8
CO
CH
3.6
3.4
3.2
BL
LH
RS
3.0
LW
AW
2.8
-28
-27
-26
-25
-24
-23
d C
13
-22
-21
-20
-19
-18
5.0
Take-home messages:
1909-1929
4.8
4.6
Trophic position
Red = deepwater ciscoes
Blue = shallow-water ciscoes
Yellow = Lake trout
Light blue = non-natives
1) Lake trout shifted to pelagic, feed
more on non-native rainbow smelt
and alewives
4.4
4.2
4.0
LT
3.8
3.6
3.4
KY
BL
BFSN
DW LJ
3.2
SJ
LH
LW
3.0
2.8
-28
-27
-26
-25
-24
-23
-22
-21
-18
1975-2002
4.8
4.6
Trophic position
3) Exotics distinct from natives, but
now occupy niche space similar to
historical natives….
-19
d13C
5.0
2) Deepwater cisco niche space
shrinks due to extirpations
-20
4.4
LT
4.2
4.0
SL
3.8
CO
CH
3.6
3.4
3.2
BL
LH
RS
3.0
LW
AW
2.8
-28
-27
-26
-25
-24
-23
d C
13
-22
-21
-20
-19
-18
Outline
Food web studies
Addressing questions at broader spatial
and temporal scale (landscape)
Application of science to
environmental management
Stable isotope
food web
studies
Prevention (invasive species, nutrient pollution)
Restoration (Great Lakes)
Preservation (Mongolia)
Applications to basic
research questions
Importance of benthic production in lakes
Land-lake linkages
Management of Hucho taimen in Mongolia
Catch-and-release flyfishing
Taimen as a conservation tool
Implement payment for ecosystem services-based
resource management
Population model for
simulating fishery
impacts
Jensen et al. 2009 CJFAS
Movement and
migration
Gilroy et al. EFF in review
Map of proposed fisheries management
zones for Mongolia
Vander Zanden et al. 2007. Ecol. Appl.
Outline
Food web studies
Addressing questions at broader spatial
and temporal scale (landscape)
Applications to
management and policy
Use of stable
isotopes
to study food web
-Prevention (invasive species, nutrient pollution)
-Restoration (Great Lakes)
-Preservation (Mongolia)
Applications to basic
research questions
-Importance of benthic production in lakes
-Land-lake linkages
46
Benthic food
chain
Pelagic food
chain
Pelagio-centrism
in limnology
200
a
Primary producers
150
100
Number of papers
50
0
50
b
Heterotrophic
bacteria
40
30
20
10
0
50
c
Invertebrates
40
Data from papers
published in 1990s
30
20
10
0
Vadeboncoeur et al. 2002. Bioscience 52: 44-54
Pelagic
Benthic
Both
Fishes heavily supported by benthic pathways
Fishes as integrators of benthic and pelagic
Number of populations
30
Fish reliance on benthic carbon
(79 populations)
25
20
15
10
5
0
0
20
40
60
80
Percent benthic reliance
Vander Zanden & Vadeboncoeur, 2002. Ecology 83: 2152-2161
100
Benthic production – contribution to whole
lake production
N = 29 lakes
N = 3 lakes
N = 15 lakes
% whole-lake production
100
Pelagic
80
60
40
20
Benthic
0
Primary
producers
Vadeboncoeur et al. 2002. BioScience 52: 44-54
Bacteria
Invertebrates
Importance of benthic production
Benthic production more efficiently channeled to higher
trophic levels
Benthic production supports the majority of fish, even in large
lakes
Benthic habitats support the majority of lake biodiversity
Fish benthivory drives top-down control in pelagic zone
Outline
Food web studies
Addressing questions at broader spatial
and temporal scale (landscape)
Applications to
management and policy
Use of stable
isotopes
to study food web
-Prevention (invasive species, nutrient pollution)
-Restoration (Great Lakes)
-Preservation (Mongolia)
Applications to basic
research questions
-Importance of benthic production in lakes
-Land-lake linkages