Biodiversity influences on mangrove forest ecosystem ... · Biodiversity influences on mangrove forest ecosystem services delivery Clare Duncan1,2, Jurgenne H. Primavera3,4, Heather

Biodiversity influences on mangrove

forest ecosystem services delivery

Clare Duncan1,2, Jurgenne H. Primavera3,4,

Heather J. Koldewey3,5, Julian R. Thompson2, Nathalie Pettorelli1

1 Institute of Zoology, ZSL, Regent’s Park, London NW1 4RY UK

2 UCL Department of Geography, Gower Street, London WC1E 6BT UK

3 ZSL Conservation Programmes, Regent’s Park, London NW1 4RY UK

4 ZSL-Philippines, 43-E Burgos Street, Barangay Magdalo, La Paz, 5000 Iloilo City, Philippines

5 Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9EZ UK

Current state of play…

• Mangroves are in global decline

FAO (2005).

Richards & Friess (2016).

• Loss of climate change

mitigation & adaptation

(CCMA) ES

Martine Perret.

International Labour.

Current state of play…

• Diversity is also declining

Polidoro et al. (2010).

DISTRIBUTION OF THREATENED SPECIES

• Mid- to upper-intertidal; selective cutting

Current state of play…

• Rehabilitation efforts often

species-poor or monoculture

Jurgenne H. Primavera.

Current state of play…

What does this mean for mangrove ES?

Does floristic diversity drive climate change

mitigation and adaptation ecosystem

services (ES) of mangrove forests?

• Terrestrial forests: flora richness can increase ecosystem functioning

• Mechanism = functional

differences

(complementarity in

resource use or

facilitation)

• Species richness not

important?

Gamfeldt et al. (2013).

Biodiversity & ES

• Terrestrial forests: saturating or mixed relationships

• Mechanism = functional

identity of the most

dominant species

• Could these mechanisms

= ES trade-offs?

Gamfeldt et al. (2013).

Biodiversity & ES

Complementarity in Mangroves…?

1: Leitão (2016).

• Species-poor systems – complementarity/facilitation may be strong?1

Complementarity in Mangroves…?

1: Leitão (2016).

• Species-poor systems – complementarity/facilitation may be strong?1

Lang’at et al. (2011).

1: Leitão (2016).

Complementarity in Mangroves…?

• Species-poor systems – complementarity/facilitation may be strong?1

• Many forests monospecific & still function fine – dominant species?

Huxham et al. (2010).

1: Leitão (2016).

Complementarity in Mangroves…?

• Species-poor systems – complementarity/facilitation may be strong?1

• Many forests monospecific & still function fine – dominant species?

• Narrow niche space & water constraints = morphological convergence

1: Leitão (2016).

Complementarity in Mangroves…?

• Species-poor systems – complementarity/facilitation may be strong?1

• Many forests monospecific & still function fine – dominant species?

• Narrow niche space & water constraints = morphological convergence

• Species-poor mangroves: genetic diversity - plasticity?

1: Leitão (2016).; 2: Balun (2011).

Complementarity in Mangroves…?

• Species-poor systems – complementarity/facilitation may be strong?1

• Many forests monospecific & still function fine – dominant species?

• Narrow niche space & water constraints = morphological convergence

• Species-poor mangroves: genetic diversity - plasticity?

• Hyperdiverse mangroves: functional traits vary between and within

zones2

CCMA ES in Diverse Mangroves…

• Does species richness matter for C stocks & storm surge

attenuation?

• Does complementarity or dominant functional identity

drive these?

• Are there mechanism- or functional trait-based trade-offs

between delivery of different mangrove CCMA ES?

Methodology - Which Traits?

RESOURCE USE STRATEGY

Specific leaf

area (SLA)

Wood density

Aerial roots Growth form

Maximum height

Methodology - Which Traits?

Specific leaf

area (SLA)

Wood density

Aerial roots Growth form

Maximum height

STRUCTURAL

RESOURCE USE STRATEGY

Methodology – Study Sites

Methodology – Study Sites

19 species

75.5 ha

7 species

7.8 ha

9 species

7.7 ha

9 species

27.5 ha

6 species

3.2 ha

Methodology – Study Sites

27 species

72 ha

19 species

75.5 ha

7 species

7.8 ha

9 species

7.7 ha

9 species

27.5 ha

6 species

3.2 ha

1: Kauffman & Donato (2010); 2: Komiyama et al. (2005); 3: Fu & Wu (2011); 4: Mazda et al. (1997); 5: Kattge et al. (2011);

6: Zanne et al. (2009); 7: Primavera et al. (2004); 8: Laliberté & Legendre (2010); 9: Conti & Díaz (2013).

• Temporary field plots – N = 79

• C stock & veg structure1-3

• Storm surge attenuation = Le4 at 2.7 m

• Species-specific wood density, SLA,

max height, growth form, aerial roots5-7

• SR & functional trait indices8,9

• Control for site & zonation

• Model averaging – relative variable importance

Methodology – Field + Lab

Results

• DOMINANCE of taller species = increased carbon stock

VEGETATION CWi = 1.00

R2 M = 0.21

R2 C = 0.45

SEDIMENT CWi = 0.83

R2 M = 0.07

R2 C = 0.56

Results

Wi = 0.51

R2 M = 0.30

R2 C = 0.49

Wi = 0.49

R2 M = 0.25

R2 C = 0.41

• DIVERSITY of height & all traits = increased storm surge

attenuation potential

Results

Wi = 0.51

R2 M = 0.30

R2 C = 0.49

Wi = 0.49

R2 M = 0.25

R2 C = 0.41

• DIVERSITY of height & all traits = increased storm surge

attenuation potential

Results

• No correlation between

storm surge attenuation

potential & C stocks

• Real trade-off in

mechanisms driving

CCMA ES?

Summary

IMPLICATIONS:

• No evidence species richness is important for mangrove CCMA ES

Summary

IMPLICATIONS:

• No evidence species richness is important for mangrove CCMA ES

• Functional diversity in structural traits may be key for coastal protection

Summary

IMPLICATIONS:

• No evidence species richness is important for mangrove CCMA ES

• Functional diversity in structural traits may be key for coastal protection

• Monoculture may be sufficient for high C stocks?

Summary

IMPLICATIONS:

• No evidence species richness is important for mangrove CCMA ES

• Functional diversity in structural traits may be key for coastal protection

• Monoculture may be sufficient for high C stocks?

• Trade-off between C stocks & storm surge attenuation due to traits?

Summary

IMPLICATIONS:

• No evidence species richness is important for mangrove CCMA ES

• Functional diversity in structural traits may be key for coastal protection

• Monoculture may be sufficient for high C stocks?

• Trade-off between C stocks & storm surge attenuation due to traits?

• Greenbelt rehabilitation to maintain functional diversity (MIT focus?)

Summary

IMPLICATIONS:

• No evidence species richness is important for mangrove CCMA ES

• Functional diversity in structural traits may be key for coastal protection

• Monoculture may be sufficient for high C stocks?

• Trade-off between C stocks & storm surge attenuation due to traits?

• Greenbelt rehabilitation to maintain functional diversity (MIT focus?)

QUESTIONS:

• Are these the right traits?

Summary

IMPLICATIONS:

• No evidence species richness is important for mangrove CCMA ES

• Functional diversity in structural traits may be key for coastal protection

• Monoculture may be sufficient for high C stocks?

• Trade-off between C stocks & storm surge attenuation due to traits?

• Greenbelt rehabilitation to maintain functional diversity (MIT focus?)

QUESTIONS:

• Are these the right traits?

• Plasticity in low diversity mangroves?

Summary

IMPLICATIONS:

• No evidence species richness is important for mangrove CCMA ES

• Functional diversity in structural traits may be key for coastal protection

• Monoculture may be sufficient for high C stocks?

• Trade-off between C stocks & storm surge attenuation due to traits?

• Greenbelt rehabilitation to maintain functional diversity (MIT focus?)

QUESTIONS:

• Are these the right traits?

• Plasticity in low diversity mangroves?

• Wider trophic interactions?

Thanks!

Municipalities of Dumangas, Ajuy, Panay, Ivisan, Kalibo and Ibajay

Field assistants

Bureau of Soils & Water Management, Cebu

TRY Initiative Global Database on Plant Traits – DIVERSITAS/GBP & Max Planck

ZSL-Philippines

Funding: The Rufford Foundation & The Darwin Initiative