Loss of Rare Fish Species from Tropical Floodplain Food Webs Affects Community Structure and Ecosystem Multifunctionality in a Mesocosm Experiment

Leibniz Center for Tropical Marine Ecology, Germany
PLoS ONE (Impact Factor: 3.23). 01/2014; 9(1):e84568. DOI: 10.1371/journal.pone.0084568
Source: PubMed


Experiments with realistic scenarios of species loss from multitrophic ecosystems may improve insight into how biodiversity affects ecosystem functioning. Using 1000 L mesocoms, we examined effects of nonrandom species loss on community structure and ecosystem functioning of experimental food webs based on multitrophic tropical floodplain lagoon ecosystems. Realistic biodiversity scenarios were developed based on long-term field surveys, and experimental assemblages replicated sequential loss of rare species which occurred across all trophic levels of these complex food webs. Response variables represented multiple components of ecosystem functioning, including nutrient cycling, primary and secondary production, organic matter accumulation and whole ecosystem metabolism. Species richness significantly affected ecosystem function, even after statistically controlling for potentially confounding factors such as total biomass and direct trophic interactions. Overall, loss of rare species was generally associated with lower nutrient concentrations, phytoplankton and zooplankton densities, and whole ecosystem metabolism when compared with more diverse assemblages. This pattern was also observed for overall ecosystem multifunctionality, a combined metric representing the ability of an ecosystem to simultaneously maintain multiple functions. One key exception was attributed to time-dependent effects of intraguild predation, which initially increased values for most ecosystem response variables, but resulted in decreases over time likely due to reduced nutrient remineralization by surviving predators. At the same time, loss of species did not result in strong trophic cascades, possibly a result of compensation and complexity of these multitrophic ecosystems along with a dominance of bottom-up effects. Our results indicate that although rare species may comprise minor components of communities, their loss can have profound ecosystem consequences across multiple trophic levels due to a combination of direct and indirect effects in diverse multitrophic ecosystems.

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    • "The detection of these patterns allows the possibility of a more precise conservation plan for the area, defining the priorities in detail. The fish fauna of freshwater ecosystems have suffered directly from the impacts associated with urban population growth (Pendleton et al. 2014). Other factors such as the introduction of exotic species (Vitule 2012), pollution and deforestation (Carvalho et al. 2012), busbaraquatic ecosystems (Burns et al. 2006, Barletta et al. 2010), and predatory fishing have contributed significantly to the decline in species richness. "
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    Full-text · Article · Nov 2015 · Biota Neotropica
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    • "They lower the diversity of structural features preferred by fish and other aquatic organisms and disrupt longitudinal connectivity, which are translated into biodiversity losses (Bunn and Arthington, 2002; Poff and Zimmerman, 2010; Webb et al., 2013). Recent studies have shown a link between local species loss and changes in ecosystem functioning (Balvanera et al., 2006; Cardinale et al., 2006; Taylor et al., 2006; Pendleton et al., 2014). Ecological consequences of damming are especially alarming for tropical regions where many large rivers have been modified to some extent by large hydroelectric dams (Araújo et al., 2013), and the construction of many more are expected (Marques et al., 2009). "
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    Full-text · Article · Sep 2015 · Ecohydrology
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    • "The M-index is statistically robust (Maestre et al., 2012), is being increasingly used (e.g. Pendleton et al., 2014; Wagg et al., 2014) and is related to other widely used multifunctionality metrics (Byrnes et al., 2014). Multifunctionality measurements may obscure specific responses for the different soil variables measured. "
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