Download Biodiversity and ecosystem functioning in rockpools

Biodiversity and ecosystem
functioning in rockpools
WHY ROCKPOOLS?
•Accessible
•Mesocosm features when emersed
•Open to the marine environment when immersed
•Diverse array of primary producers and consumers
•A range of emergent ecosystem properties can be measured
Primary production
Balance between community respiration and production
Nutrient uptake
WHY NOT ROCKPOOLS?
•Variability in size, shape, complexity
•Availability :
•Natural?
•Artificial?
Biodiversity-ecosystem functioning
Rockpools as model
experimental systems:
1) Susceptibility of marine algal communities to alien invasion:
the role of functional diversity
2) Top down and bottom up control of rockpool algal
communiuties:the importance of species identity in ecosystem
functioning
3) Biodiversity and ecosystem functioning: tests using rockpools
as natural mesocosms
1) Susceptibility of marine algal communities to alien
invasion: the role of functional diversity
PICTURE
Sargassum muticum
NERC Small Grant
(NER/B/S/2003/00266)
2) Top down and bottom up control of rockpool algal
communiuties:the importance of species identity in
ecosystem functioning
• Top down- dominant grazer Patellid
limpets
• Bottom up - nutrient supply
Factorial experiment
Treatment
1
2
3
4
Grazer
+
+
-
Nutrient
+
+
-
Ephemeral algal cover
100
% cover
- Nutrients
+ Nutrients
Two way ANOVA
Grazers P < 0.05
Nutrients P < 0.001
50
0
+ Grazers
- Grazers
Net primary production
mg O2 l-1 min-1
0.25
0.20
- Nutrients
+ Nutrients
0.15
?
0.10
0.05
0
+ Grazers
- Grazers
Two way ANOVA
Grazers x Nutrients P < 0.001
Species identity dictates ‘ecosystem
functioning’
Variety of ephemeral species respond to experimental
perturbations
Highly productive
green algae
mg O2 l-1 min-1
0.25
0.20
- Nutrients
+ Nutrients
0.15
?
0.10
Red algae Ceramium spp.
0.05
0
+ Grazers
- Grazers
of low productivity
Ephemeral algal cover
100
% cover
- Nutrients
+ Nutrients
Two way ANOVA
Grazers P < 0.05
Nutrients P < 0.001
50
0
+ Grazers
- Grazers
Net primary production
mg O2 l-1 min-1
0.25
0.20
- Nutrients
+ Nutrients
0.15
Two way ANOVA
Grazers x Nutrients P < 0.001
0.10
0.05
0
+ Grazers
- Grazers
3) Biodiversity and ecosystem functioning: tests
using rockpools as natural mesocosms
Observational correlative
approach
Models relating
physical and
biological variables
to key ecosystem
properties
Manipulative experimental
approach
NERC Standard Grant (NE/B504649/1) (Jenkins, Thompson, Hawkins, Burrows)
Key questions:
•Develop statistical models linking physical and biological attributes to
ecosystem functions.
•To determine the relative importance of functional versus species
diversity in controlling ecosystem function and assess the specific role of
identity.
•To determine how consumer diversity affects primary producer diversity
and biomass and establish the consequences for ecosystem functioning.
•To determine changes in ecosystem function occurring as a
consequence of natural succession
•To use a modelling approach to link observations made in natural
systems and experiments, to provide a predictive understanding of
biodiversity loss in the marine environment.