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The Relationship between Phytoplankton Evenness and Copepod Abundance in Lake Nansihu, China

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ABSTRACT

The relationship between biodiversity and ecosystem functioning is a central issue in ecology. Previous studies have shown that producer diversity can impact the consumer community via predator-prey interactions. However, direct observations of this relationship remain rare, in particular for aquatic ecosystems. In this research, the relationship between phytoplankton diversity (species richness and evenness) and the abundance of copepods was analyzed in Lake Nansihu, a meso-eutrophic lake in China. The results showed that copepods abundance was significantly decreased with increasing phytoplankton evenness throughout the year. However, both species richness and phytoplankton biomass showed no significant relationship with the abundance of copepods. Canonical correspondence analysis revealed that phytoplankton evenness was negatively correlated with Thermocyclops kawamurai, Cyclops vicinus, Eucyclops serrulatus, Mesocyclops leuckarti, Sinocalanus tenellus, Sinocalanus dorrii, Copepods nauplius, but positively correlated with many Cyanophyta species (Chroococcus minutus, Dactylococcopsis acicularis, Microcystis incerta, Merismopedia tenuissima, Merismopedia sinica and Lyngbya limnetica). Based on our results, phytoplankton evenness was a better predictor of copepods abundance in meso-eutrophic lakes. These results provide new insights into the relationship between diversity and ecosystem functioning in aquatic ecosystems.

No MeSH data available.


Relationships between phytoplankton biomass and copepod abundance in different seasons.
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ijerph-13-00855-f007: Relationships between phytoplankton biomass and copepod abundance in different seasons.

Mentions: Pearson correlation coefficients between phytoplankton biomass and copepod abundance for the four seasons were R = 0.030, R = −0.146, R = −0.027, and R = −0.128, respectively, which were all insignificant (p > 0.05). However, the Linear Mixed Effects Model showed that the relationship between phytoplankton biomass and copepod abundance varied seasonally (Table 4; Figure 7). In spring, phytoplankton biomass had a positive correlation with copepod abundance and the regression slope was 3.597 (t = 6.715, p < 0.001). However, the regression slopes in summer, autumn, and winter were all positive, none were significant (Table 4). The correlation coefficients between phytoplankton evenness and biomass for the four seasons (spring, summer, autumn, and winter) were R = −0.153, R = −0.103, R = −0.211, and R = −0.171, respectively. In addition, the correlation coefficients between phytoplankton species richness and biomass were always insignificant (spring: R = 0.213; summer: R = 0.106; autumn: R = 0.057; winter, R = 0.206). These results showed that phytoplankton evenness and species richness had no significant correlation with biomass.


The Relationship between Phytoplankton Evenness and Copepod Abundance in Lake Nansihu, China
Relationships between phytoplankton biomass and copepod abundance in different seasons.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036688&req=5

ijerph-13-00855-f007: Relationships between phytoplankton biomass and copepod abundance in different seasons.
Mentions: Pearson correlation coefficients between phytoplankton biomass and copepod abundance for the four seasons were R = 0.030, R = −0.146, R = −0.027, and R = −0.128, respectively, which were all insignificant (p > 0.05). However, the Linear Mixed Effects Model showed that the relationship between phytoplankton biomass and copepod abundance varied seasonally (Table 4; Figure 7). In spring, phytoplankton biomass had a positive correlation with copepod abundance and the regression slope was 3.597 (t = 6.715, p < 0.001). However, the regression slopes in summer, autumn, and winter were all positive, none were significant (Table 4). The correlation coefficients between phytoplankton evenness and biomass for the four seasons (spring, summer, autumn, and winter) were R = −0.153, R = −0.103, R = −0.211, and R = −0.171, respectively. In addition, the correlation coefficients between phytoplankton species richness and biomass were always insignificant (spring: R = 0.213; summer: R = 0.106; autumn: R = 0.057; winter, R = 0.206). These results showed that phytoplankton evenness and species richness had no significant correlation with biomass.

View Article: PubMed Central - PubMed

ABSTRACT

The relationship between biodiversity and ecosystem functioning is a central issue in ecology. Previous studies have shown that producer diversity can impact the consumer community via predator-prey interactions. However, direct observations of this relationship remain rare, in particular for aquatic ecosystems. In this research, the relationship between phytoplankton diversity (species richness and evenness) and the abundance of copepods was analyzed in Lake Nansihu, a meso-eutrophic lake in China. The results showed that copepods abundance was significantly decreased with increasing phytoplankton evenness throughout the year. However, both species richness and phytoplankton biomass showed no significant relationship with the abundance of copepods. Canonical correspondence analysis revealed that phytoplankton evenness was negatively correlated with Thermocyclops kawamurai, Cyclops vicinus, Eucyclops serrulatus, Mesocyclops leuckarti, Sinocalanus tenellus, Sinocalanus dorrii, Copepods nauplius, but positively correlated with many Cyanophyta species (Chroococcus minutus, Dactylococcopsis acicularis, Microcystis incerta, Merismopedia tenuissima, Merismopedia sinica and Lyngbya limnetica). Based on our results, phytoplankton evenness was a better predictor of copepods abundance in meso-eutrophic lakes. These results provide new insights into the relationship between diversity and ecosystem functioning in aquatic ecosystems.

No MeSH data available.