Contrasting Ecosystem-Effects of Morphologically Similar Copepods

Matthews Blake, Stephen Hausch, Christian Winter, Curtis Suttle, Jonathan B. Shurin

Organisms alter the biotic and abiotic conditions of ecosystems. They can modulate the availability of resources to other

species (ecosystem engineering) and shape selection pressures on other organisms (niche construction). Very little is known

about how the engineering effects of organisms vary among and within species, and, as a result, the ecosystem

consequences of species diversification and phenotypic evolution are poorly understood. Here, using a common gardening

experiment, we test whether morphologically similar species and populations of Diaptomidae copepods (Leptodiaptomus

ashlandi, Hesperodiaptomus franciscanus, Skistodiaptomus oregonensis) have similar or different effects on the structure and

function of freshwater ecosystems. We found that copepod species had contrasting effects on algal biomass, ammonium

concentrations, and sedimentation rates, and that copepod populations had contrasting effects on prokaryote abundance,

sedimentation rates, and gross primary productivity. The average size of ecosystem-effect contrasts between species was

similar to those between populations, and was comparable to those between fish species and populations measured in

previous common gardening experiments. Our results suggest that subtle morphological variation among and within

species can cause multifarious and divergent ecosystem-effects. We conclude that using morphological trait variation to

assess the functional similarity of organisms may underestimate the importance of species and population diversity for

ecosystem functioning.

Functional and Evolutionary Ecology
External organisation(s)
Eidgenössische Technische Hochschule Zürich, University of Calgary, University of British Columbia (UBC), University of California, San Diego
Publication date
Peer reviewed
Austrian Fields of Science 2012
106022 Microbiology
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