Mekong Mollusc Biodiversity, Fisheries and their Relations to Climatic and Physical-Chemical...
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Transcript of Mekong Mollusc Biodiversity, Fisheries and their Relations to Climatic and Physical-Chemical...
Mollusc Biodiversity, Fisheries and Their Relations to Climatic and Physical-Chemical
Conditions
*Corresponding: [email protected]
24th July 2017
Ratha Sor1,2*, Young-Seuk Park3, Pengbun Ngor2 and Sovan Lek2
1*Department of Biology, Royal University of Phnom Penh, Cambodia2 Laboratoire Evolution & Diversité Biologique, University of Toulouse – UPS III, France
3Department of Life and Nanopharmaceutical Sciences and Department of Biology, Kyung Hee
University, Seoul 130-701, Republic of Korea.
Molluscs in Ecosystems
2
• A key component of freshwater ecosystems
• Contributing to bioturbation and filtration in freshwater systems
(Bogan, 2008; Covich et al., 1999; Palmer et al., 1997).
(Chea et al., 2017)
Mollusc biodiversity in the Mekong
3Gupta (2009)
• The Lower Mekong Basin (LMB) is a hotspot zone supporting a high diversity of molluscs (Bogan, 2008; Strong et al., 2008).
• ~121 species of gastropods• ~39 species of bivalves • At least 111 gastropods and 5
bivalves are endemic
~4,350 km from the source
• In the Tonle Sap Lake and River systems, molluscs are the second fisheryproduction after fishes (Rainboth, 1996)
What lies ahead?
4
1) To investigate investigated mollusc biodiversity and community patterns in response to physical-chemical, land cover and climatic variables in the Lower Mekong Basin
2) To assesse the landed mollusc fisheries around the Tonle Sap Lake
Scarce number of studies on mollusc diversity, patterns, fisheries and their responses to environmental gradients in the LMB(Quang et al. 2013)
Study area and samples
5
• 109 mollusc samples (63 sites) from 2004 to 2008, every March
• Independent variables:
• Physical-chemical variables• Land cover types• Climatic variables (bioclim)
• Landed fisheries: 3 species • Corbicula moreletiana• Pila ampullaceal • P. polita
• Daily landed biomass
Biodiversity and Community Patterns
7
• 98 mollusc taxa, the most common species include• Corbicula tenuis (65.1%), Stenothyra koratensis holosculpta
(28.6%), C. lamarckiana (26.8%), and Limnoperna siamensis(23.8%)
• The most abundance species were: C. leviuscula (17.3%), L. siamensis (12.6%), C. tenuis (11.9%), C. lamarckiana (8.5%).
• 21 families, the most common families include • Unionidae (17.6%)• Corbiculidae (13.7%)• Viviparidae (11.8%)• Pomatiopsidae (10.8%) and Stenothyridae (10.8%).
Biodiversity and Community Patterns
8
Cluster Dendrogram
He
igh
t
1 3 2
01
23
45
6• 3 clusters could be distinguished
Legend
N
Cluster 1
Cluster 2
Cluster 3
Major River
0 120 240 Km
Biodiversity and Community Patterns
Cluster 1 Cluster 2 Cluster 3
Legend
N
Cluster 1
Cluster 2
Cluster 3
Major River
0 120 240 Km
Functional Community Patterns
40 3955
6 6
4
54 5542
Cl.1 Cl.2 Cl.3
Scraper (%)
Gatherer-Collector (%)
Filter-Collector (%)
-0.5 0.0 0.5 1.0
-0.5
0.0
0.5
RDA1 (13%)
RD
A2
(1
0%
)
-10
1
SAWRD
EC
TEM
Urb
Evg.all
Agr
Reg
bio1
bio3
bio5bio7
bio15
bio17
22
22
3
1
2 2
1
2
2
2
2
11 1
2
2
2
11
2
2
2
2
2
11
1 1
22
2
3
2
2
2
2
1
2
2
2
2
1
2
22
2
2
33
33
3
333
333
2
1
3
Cor.ten
Cor.sp
Afr.cla
Lim.siaCor.lam Lim.sp
Sin.har
Cor.spCor.bau
Cor.morAng.spPac.sp
Hub.spSte.sp
Ste.kor
Relationship between communities with environment
Relationship between communities with environment
Physical-chemical Land covers
Climatic
0.03 0.02
0.10
0.010.05
0.01
Residuals = 0.79
Landed mollusc fisheries around the Tonle Sap
Species
Total
biomass
Total values
in dollar ($)*
C. moreletiana 6,436,439 369,805
P. polita 1,511,280 781,025
P. ampullacea 381,899 218,053
-1.0 -0.5 0.0 0.5 1.0
-0.5
0.0
0.5
1.0
NMDS1
NM
DS
2
Cmor.inc
Pamp.inc
Ppol. mass
02
03
04
05
09
10
11
12
wl.m
mean.t
mean.pre
0.9 0 0.9
00
.9
01Ppol.inc
Cmor.massPamp.mass
Landed mollusc fisheries around the Tonle Sap
Summary and implications
• Mollusc diversity increases from the upstream to the down stream
• Climatic and water quality variable are the determinants, driving the different organization of
• Filter-collectors are more diverse in the downstream
• Mollusc fisheries contributes to food security, employment and economy, especially for the poorer segment of the society (Balian et al., 2008)
diversity
+
Acknowledgements