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Species richness and trophic diversity increase decomposition in a co-evolved food web.

Baiser B, Ardeshiri RS, Ellison AM - PLoS ONE (2011)

Bottom Line: Knowledge of how this biodiversity relates to ecosystem functioning is important for understanding the maintenance of diversity and the potential effects of species losses and gains on ecosystems.We show that species richness and trophic diversity underlie strong linkages between food web structure and dynamics that influence ecosystem functioning.The importance of trophic diversity and species interactions in determining how biodiversity relates to ecosystem functioning suggests that simply focusing on species richness does not give a complete picture as to how ecosystems may change with the loss or gain of species.

View Article: PubMed Central - PubMed

Affiliation: Harvard Forest, Harvard University, Petersham, Massachusetts, United States of America. bbaiser@fas.harvard.edu

ABSTRACT
Ecological communities show great variation in species richness, composition and food web structure across similar and diverse ecosystems. Knowledge of how this biodiversity relates to ecosystem functioning is important for understanding the maintenance of diversity and the potential effects of species losses and gains on ecosystems. While research often focuses on how variation in species richness influences ecosystem processes, assessing species richness in a food web context can provide further insight into the relationship between diversity and ecosystem functioning and elucidate potential mechanisms underpinning this relationship. Here, we assessed how species richness and trophic diversity affect decomposition rates in a complete aquatic food web: the five trophic level web that occurs within water-filled leaves of the northern pitcher plant, Sarracenia purpurea. We identified a trophic cascade in which top-predators--larvae of the pitcher-plant mosquito--indirectly increased bacterial decomposition by preying on bactivorous protozoa. Our data also revealed a facultative relationship in which larvae of the pitcher-plant midge increased bacterial decomposition by shredding detritus. These important interactions occur only in food webs with high trophic diversity, which in turn only occur in food webs with high species richness. We show that species richness and trophic diversity underlie strong linkages between food web structure and dynamics that influence ecosystem functioning. The importance of trophic diversity and species interactions in determining how biodiversity relates to ecosystem functioning suggests that simply focusing on species richness does not give a complete picture as to how ecosystems may change with the loss or gain of species.

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Relationship between final species richness, final trophic diversity (TD), and decomposition.Decomposition showed a ‘hump-shaped’, polynomial relationship with species richness (A) and a positive linear relationship with TD (B). Regression models (lm in R v.2.11.1) are significant at P<0.05.
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pone-0020672-g002: Relationship between final species richness, final trophic diversity (TD), and decomposition.Decomposition showed a ‘hump-shaped’, polynomial relationship with species richness (A) and a positive linear relationship with TD (B). Regression models (lm in R v.2.11.1) are significant at P<0.05.

Mentions: Decomposition showed a ‘hump-shaped’, polynomial relationship with species richness (F2,67 = 8.3, P = 0.0006; Fig. 2a) and a positive linear relationship with TD (F1,68 = 14.59, P = 0.0003; Fig. 2b). Species richness and TD were highly correlated (R2 = 0.82, F1,68 = 306.4, P<0.0001; Figure S1). On average mass loss in ants across treatments was 72% (N = 70, SD = 21%). Ant decomposition data is available at the Harvard Forest data archive (http://harvardforest.fas. harvard.edu/data/archive.html) data set HF-169.


Species richness and trophic diversity increase decomposition in a co-evolved food web.

Baiser B, Ardeshiri RS, Ellison AM - PLoS ONE (2011)

Relationship between final species richness, final trophic diversity (TD), and decomposition.Decomposition showed a ‘hump-shaped’, polynomial relationship with species richness (A) and a positive linear relationship with TD (B). Regression models (lm in R v.2.11.1) are significant at P<0.05.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3108618&req=5

pone-0020672-g002: Relationship between final species richness, final trophic diversity (TD), and decomposition.Decomposition showed a ‘hump-shaped’, polynomial relationship with species richness (A) and a positive linear relationship with TD (B). Regression models (lm in R v.2.11.1) are significant at P<0.05.
Mentions: Decomposition showed a ‘hump-shaped’, polynomial relationship with species richness (F2,67 = 8.3, P = 0.0006; Fig. 2a) and a positive linear relationship with TD (F1,68 = 14.59, P = 0.0003; Fig. 2b). Species richness and TD were highly correlated (R2 = 0.82, F1,68 = 306.4, P<0.0001; Figure S1). On average mass loss in ants across treatments was 72% (N = 70, SD = 21%). Ant decomposition data is available at the Harvard Forest data archive (http://harvardforest.fas. harvard.edu/data/archive.html) data set HF-169.

Bottom Line: Knowledge of how this biodiversity relates to ecosystem functioning is important for understanding the maintenance of diversity and the potential effects of species losses and gains on ecosystems.We show that species richness and trophic diversity underlie strong linkages between food web structure and dynamics that influence ecosystem functioning.The importance of trophic diversity and species interactions in determining how biodiversity relates to ecosystem functioning suggests that simply focusing on species richness does not give a complete picture as to how ecosystems may change with the loss or gain of species.

View Article: PubMed Central - PubMed

Affiliation: Harvard Forest, Harvard University, Petersham, Massachusetts, United States of America. bbaiser@fas.harvard.edu

ABSTRACT
Ecological communities show great variation in species richness, composition and food web structure across similar and diverse ecosystems. Knowledge of how this biodiversity relates to ecosystem functioning is important for understanding the maintenance of diversity and the potential effects of species losses and gains on ecosystems. While research often focuses on how variation in species richness influences ecosystem processes, assessing species richness in a food web context can provide further insight into the relationship between diversity and ecosystem functioning and elucidate potential mechanisms underpinning this relationship. Here, we assessed how species richness and trophic diversity affect decomposition rates in a complete aquatic food web: the five trophic level web that occurs within water-filled leaves of the northern pitcher plant, Sarracenia purpurea. We identified a trophic cascade in which top-predators--larvae of the pitcher-plant mosquito--indirectly increased bacterial decomposition by preying on bactivorous protozoa. Our data also revealed a facultative relationship in which larvae of the pitcher-plant midge increased bacterial decomposition by shredding detritus. These important interactions occur only in food webs with high trophic diversity, which in turn only occur in food webs with high species richness. We show that species richness and trophic diversity underlie strong linkages between food web structure and dynamics that influence ecosystem functioning. The importance of trophic diversity and species interactions in determining how biodiversity relates to ecosystem functioning suggests that simply focusing on species richness does not give a complete picture as to how ecosystems may change with the loss or gain of species.

Show MeSH
Related in: MedlinePlus