Spatio-temporal distribution of nekton community structure and … · 2020-04-30 · Species number...
Transcript of Spatio-temporal distribution of nekton community structure and … · 2020-04-30 · Species number...
Spatio-temporal distribution of nekton community structure and diversity change in Hangzhou Bay, CHINA
Reporter: Dongrong Zhang
Date: 05. 08. 2020
CONTENTS
Subject background
Research object
Research results
Summary
01
02
03
04
Content
Subject background
01 PART
(1)Estuarine bay (complexity salinity, high turbidity and well-mixed ) is closely related to human life and
productive activities as a unique ecosystem (Barbier et al., 2011);
(2)Population dynamics and influence mechanism of nekton in the estuarine bay was seriously disturbed by
human activities;
(3)Estuarine bay waters serve as spawning, feeding and nursery grounds for fish larvae, juvenile and adult
nekton (Nyitrai et al., 2012).
Subject background
Hangzhou Bay
Typical area
Research object
02 PART
Research object
Estuarine nekton
Bait
Fo
od
org
an
ism
Rich sources of nutrients
Diverse habitats
High abundance and biomass of nekton
Complex spatial patterns of nekton
Research results
03 PART
Research results-1 Nekton assemblages and composition
Eco-group
Species number Mean Biomass Mean Abundance
Spring Summer Autumn Winter Spring Summer Autumn Winter Spring Summer Autumn Winter
Fish 20 15 21 16 108.52±67.68 41.04±27.00 90.99±104.07 136.61±215.36 8.10±11.51 10.61±6.22 13.83±8.35 4.03±3.29
Shrimp 8 11 7 5 8.38±6.68 39.93±26.77 35.48±24.06 2.64±2.27 17.30±14.19 55.12±36.01 80.58±67.27 5.03±3.29
Crab 3 5 5 4 14.55±9.38 2.33±2.77 9.54±10.56 3.93±3.75 2.21±1.85 0.42±0.36 1.55±1.43 0.18±0.11
Total 31 31 33 25 131.46±73.71 83.30±47.44 136.01±108.76 143.18±215.77 27.60±17.88 66.15±39.12 95.96±67.09 9.24±4.86
(1)57 taxa distributed among 23 families (2)Mean nekton biomass:Winter(fish)> Summer(shrimp) (3)Mean nekton abundance: Warm seasons(summer, autumn) >cold seasons (winter,spring) (4) Nekton of HZB were mainly composed of small near-shore species
Research results-2 Spatial distribution of nekton community
Spatial distribution of nekton biomass (kg/km2) in HZB
Spatial distribution of nekton abundance (×103ind./km2) in HZB
Research results-3 Dominant species of nekton
Dominant species (IRI>1000) :
Fish: Miichthys miiuy,
Collichthys lucidus ;
Shrimp: Exopalaemon
annandalei, Palaemon gravieri;
Crab : Portunus trituberculatus.
Research results-4 Nekton species diversity
Spring Summer Autumn Winter
0
1
2
3
4
a
a
a
Bio
mas
s div
ersi
ty i
nd
ex (
H')
One-way ANOVA test (a)
a
Spring Summer Autumn Winter
0.0
0.3
0.6
0.9
a
a
a
One-way ANOVA test
Bio
mas
s ev
enn
ess
ind
ex (
J')
(b)
a
Spring Summer Autumn Winter
0
1
2
3
aa
a
a
Non-parametric Kruskal-Wallis H test
Bio
mas
s ri
chn
ess
ind
ex (
d)
(c)
Spring Summer Autumn Winter
1
2
3 acbc
b
Abu
nd
ance
div
ersi
ty i
ndex
(H
')
(d)
a
Non-parametric Kruskal-Wallis H test
Spring Summer Autumn Winter
0.0
0.3
0.6
0.9 c
b
ab
Abu
nd
ance
ev
enn
ess
index
(J'
)
(e)Non-parametric Kruskal-Wallis H test
ac
Spring Summer Autumn Winter
0.0
0.4
0.8
1.2a
a
a
Abu
nd
ance
ric
hn
ess
index
(d
)
(f)One-way ANOVA test
a
0
50
100
150
200
250
-80
-60
-40
-20
0
20
40
60
Spring Summer Autumn Winter
Alt
ernat
e in
dex
(A
I)
Mig
rate
ind
ex (
MI)
Migrate index
Alternate index
Diversity index (H'), evenness index (J') and richness index (d): (i) Warm seasons>cold seasons (biomass); (ii) Opposite result (abundance in H' and J')
AI : 94 to 218 MI :-73 to 35 Large variation and unstable
Research results-5 Seasonal differences of nekton community structure
A01
A10
A02
A04
A07
A03
A08
A05
A06
A09
Sam
plin
g sites
50 60 70 80 90 100 Bray-Curtis similarity coefficient(%)
(a) Hierarchical cluster analysis of nekton biomass in spring
B08
B10
B09
B07
B04
B06
B05
B01
B02
B03
Sam
plin
g sites
40 60 80 100
Bray-Curtis similarity coefficient(%)
(b) Hierarchical cluster analysis of nekton biomass in summer
C10
C05
C07
C04
C06
C09
C08
C03
C01
C02
Sam
plin
g sites
50 60 70 80 90 100 Bray-Curtis similarity coefficient(%)
(c) Hierarchical cluster analysis of nekton biomass in autumn
D03
D01
D02
D10
D06
D08
D07
D09
D04
D05
Sam
plin
g sites
40 60 80 100 Bray-Curtis similarity coefficient(%)
(d) Hierarchical cluster analysis of nekton biomass in winter
(a) Spring : 3 groups(60%);
(b) Summer : 4 groups(65%);
(c) Autumn: 3 groups(65%);
(d) Winter: 3 groups(55%).
ANOSIM analysis results :
difference between seasons
reached the significance level
(Global R=0.616, P=0.0001)
Research results-6 Relationship between nekton and environmental variables
Redundancy analysis (RDA): (a) negative correlated with salinity; (b) DO and surface salinity positive
correlated; negative correlated with DIP;
(c) Depth showed a significant positive correlation;
(d) Chla and surface temperature were highly positive correlated.
Summary
04 PART
Summary
The community of nekton in Hangzhou Bay showed significant spatio-temporal variation
With the index of H', J', d, AI, and MI , the community was not stable comfortably
The community of nekton could be divided into 3~4 groups in the 55%~65% similarity levels in four seasons
Physico-chemical factors were highly correlated with the nekton biomass
Thank you for
your attention!