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Investigating the linkage between biodiversity and ecosystem lab.agr. · PDF file 2008-08-02 · Investigating the linkage between biodiversity and ecosystem functions in coastal areas

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  • Investigating the linkage between biodiversity and ecosystem functions

    in coastal areas

    Masahiro Nakaoka1,2), Akihito Aizawa1), Teruko Demise1), Takuya Era1), Shuko Kato1) and Kentaro Watanabe1)

    1) Chiba University 2) Current address: Akkeshi Marine Station, Field Science

    Center for Northern Biosphere, Hokkaido University

    E-mail: [email protected]

  • Adaptive management of biodiversity and functions of coastal ecosystems

    Q: Where to conserve?

    A1: A site with highest biodiversity (for conservationists)

    A2: A site with highest productivity (for fishermen)

    Are the answers the same?

  • Biodiversity enhances ecosystem functions

    BD-EF relationship Positive link between biodiversity and ecosystem functions revealed by manipulative experiments

    Tillman (2000) plant species richness

    co m

    m un

    ity b

    io m

    as s

    Questions and problems 1. Which measures of biodiversity should be used?

    2. Does the rule hold at larger spatial scales?

    Fewer research has been done in marine ecosystems.

  • Which measure of biodiversity ?

    1. Definition at different biological levels Genetic diversity at population level Species diversity at community level Landscape diversity at ecosystem level

    2. Spatial scale of biodiversity α diversity: diversity within a patch β diversity: difference between patches γ diversity: diversity of whole area

    P

    P

    P

  • BD-EF relationship changes among regions

    Hector et al (1999) species loss

    bi om

    as s

    Environmental factors interfere with BD-EF relationship at broad spatial scales.

  • Purpose of the present study Investigating possible relationships among environmental factors,

    biodiversity and ecosystem functions in coastal habitats

    Adaptive management of biodiversity, ecosystem functions and services

    Environmental gradients Resource availability Modulators (temp, pH) Disturbance regime

    Biodiversity Composition Richness and evenness Species interactions

    Ecosystem functions Productivity Resistance and Resilience Stability

  • Case studies at two different habitats

    Rocky intertidal community along the Pacific coast of Japan

    Seagrass beds in Tokyo Bay

  • Known as most productive habitats in the world (annual productivity exceeding tropical rain forest)

    Harbor diverse plant and animals species, forming “hot spot” of biodiversity in marine ecosystems

    What is seagrass bed?

    A unit of coastal landscape consisting of seagrasses, i.e., “flowering plants living in the sea” (Do not confuse with seaweeds!)

  • Study sites

    Tokyo Bay 17 stations in 5 areas established in a nested design (although not perfectly designed)

    Seagrass bed in Futtsu

  • Analysis of genetic diversity of eelgrass using microsatellite DNA

    Collection of eelgrass

    DNA estraction by CTAB method

    Calculation of genetic diversity

    115 117

    98 107

    98 121

    (bp)

    PCR amplification

    Determionation of genotypes

    Electrophoresis

  • Analysis of genetic diversity of eelgrass using microsatellite DNA

    0 .0

    0 .2

    0 .4

    0 .6

    0 .8

    1 .0

    KK1 KK2 FT1 FT2 FT3 TK1 TK2 YH YE TT1 TT2 TJ

    Fr eq

    o f h

    et er

    oz yg

    oc ity

    (H )

  • Remote sensing analysis on long-term changes in seagrass beds

  • Remote sensing analysis on long-term changes in seagrass beds

    0

    5 x 103

    1985 1990 1995 2000 2005 2010

    Se ag

    ra ss

    a re

    a (m

    2 )

    TK3 TK2 TT34 x 103

    3 x 103

    2 x 103

    1 x 103

  • Analyses on animal community

  • Analyses on animal community

    0

    20

    40

    60

    80

    KK FP1 FP2 FF1 FF2 TKT TKU TKS TTH TTN TTO

    Sp ec

    is ri

    ch ne

    ss

    0

    1

    2

    3

    4

    5

    KK FP1 FP2 FF1 FF2 TKT TKU TKS TTH TTN TTO

    D en

    si ty

    (m -2

    )

  • Relationships among environmental factors, biodiversity and ecosystem functions

    Positive correlation between nutrient concentration and

    density of benthic animals  (r=0.921, p=0.001)

    Positive correlation between seagrass bed area and genetic

    diversity of eelgrass  (r=0.892, p=0.042)

    2.5

    3.0

    3.5

    4.0

    0.0 0.2 0.4 0.6 0.8 1.0

    N concentration (mg/l)

    lo g (i n fa u na d e ns it y )

    4.5

    5.0

    5.5

    6.0

    6.5

    2 3 4 5 6 7

    log (seagrass bed area)

    A lle le r ic h n e ss o f e e lg ra ss

  • Relationships among environmental factors, biodiversity and ecosystem functions

    Seagrass species diversity

    Species diversity

    of epifauna Nutrient

    concentration

    Water transparency

     Water temperature

    Stability of seagrass bed

     Sediment composition

    Seagrass genetic diversity

    Species diversity of infauna

    Abundance of epifauna

    Abundance of infauna

    Seagrass bed areaPositive

    Negative

  • What is rocky intertidal community?

    Community on marine hard bottom which is exposed to severe stress when emerged at low tide

    Strong environmental gradient creates characteristic zonation pattern of organisms.

    Species interactions were strongly influenced by competition over space.

    Known as ideal system for experimental studies on population and community ecology (such as classic studies by Joseph Connell and Robert T. Paine)

  • Hierarchical census along the Pacific coast of JapanDoto

    Donan

    Sanriku

    Boso Nanki

    Osumi

    6 regions

    6 regions * 5 coasts * 5 plots =150 plots

    Chikura

    Emi

    Kominato

    Nishikawana

    Mera

    5 coasts 01

    02 0304

    05 5 plots 0 50m25

  • vertical rock wall

    Field census

    100cm

    Census plot Succession plot

    Simultaneous monitoring at all sites since 2002 Monitoring of environment (temperature, nutrient, chlorophyll a concentration, wave exposure, geology and geography of rocks) Measurement of BD and EF (see next page)

    mean tide level

    50cm

  • Biodiversity at different spatial scales

    Species richness of sessile organisms appeared at census plots between 2002 and 2005

    α1 : plot species richness α2 : coastal species richness γ : regional species richness

    αα11

    γγ

    αα22Mera Emi

    Chikura

    Nishikawana

    Kominato

  • Ecosystem functions

    1: Coverage - indicator of biomass and productivity

    (average between 2002 and 2005)

    2: Temporal variation in coverage - indicator of stability

    (C.V. of coverage between 2002 and 2005)

    3: Recovery speed from disturbance - indicator of resilience

    (coverage of the succession plot in 2004, i.e, one year after the removal of organisms)

  • Results of path analysis

    Nanki Osumi

    Coverage Coverage

    Water temperature

    α1 diversity

    Chl. a

    Rock irregularity Water

    temperature Chl. a

    .52

    .59

    .35 .40

    -.35

    -.56

    α1 diversity .67

    .34

    .36

    R2=0.70 R2=0.69

  • BD-EF relationship at different scales

    0+000+Osumi ++0-++Nanki 000000Boso +00000Sanriku 0++000Donan 00+000Doto

    --0000--0All γα2α1γα2α1γα2α1BD

    ResilienceStabilityCoverageEF

  • Discussion from the rocky shore study

    Effects of BD on EF were negative by analysis using data from all regions, but positive for each region.

    BiodiversityBiodiversity

    Ec os

    ys te

    m F

    un ct

    io n

    Ec os

    ys te

    m F

    un ct

    io n

    Plot diversity (α1) affects ecosystem functions more frequently than coastal diversity(α(α22))..

  • Conclusion

    Biodiversity measured at different spatial and biological levels is related to functions of coastal ecosystem.

    The observed BD-EF relationship varied among regions and among measures of biodiversity, suggesting importance of considering spatial scale of observation and the effects of environmental gradient.

    Combined approaches using long-term monitoring data and experimental approaches are promising to elucidate causal mechanisms for the observed relationships, which is necessary for planning adaptive management strategy for conservation of coastal ecosystem.

  • Acknowledgements

    Seagrass team: T. Yamakita, K. Yamada, N. Whanpetch, M. Hori, Y. Tanaka, N. Tanaka, M. Ishii, A. Kondoh,

    Rocky intertidal team : T. Noda, T. Yamamoto, M. Hori, T. Okuda, M. Tsujino, T. Hagino, N. Ito, T. Maruyama

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