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Climate alters intraspecific variation in copepod effect traits through pond food webs
Author(s) -
Charette Cristina,
Derry Alison M.
Publication year - 2016
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/15-0794.1
Subject(s) - intraspecific competition , copepod , biology , ecology , food web , fecundity , phytoplankton , zooplankton , interspecific competition , trophic level , population , nutrient , crustacean , sociology , demography
Abstract Essential fatty acids ( EFA s) are primarily generated by phytoplankton in aquatic ecosystems, and can limit the growth, development, and reproduction of higher consumers. Among the most critical of the EFA s are highly unsaturated fatty acids ( HUFA s), which are only produced by certain groups of phytoplankton. Changing environmental conditions can alter phytoplankton community and fatty acid composition and affect the HUFA content of higher trophic levels. Almost no research has addressed intraspecific variation in HUFA s in zooplankton, nor intraspecific relationships of HUFA s with body size and fecundity. This is despite that intraspecific variation in HUFA s can exceed interspecific variation and that intraspecific trait variation in body size and fecundity is increasingly recognized to have an important role in food web ecology (effect traits). Our study addressed the relative influences of abiotic selection and food web effects associated with climate change on intraspecific differences and interrelationships between HUFA content, body size, and fecundity of freshwater copepods. We applied structural equation modeling and regression analyses to intraspecific variation in a dominant calanoid copepod, Leptodiatomus minutus , among a series of shallow north‐temperate ponds. Climate‐driven diurnal temperature fluctuations favored the coexistence of diversity of phytoplankton groups with different temperature optima and nutritive quality. This resulted in unexpected positive relationships between temperature, copepod DHA content and body size. Temperature correlated positively with diatom biovolume, and mediated relationships between copepod HUFA content and body size, and between copepod body size and fecundity. The presence of brook trout further accentuated these positive effects in warm ponds, likely through nutrient cycling and stimulation of phytoplankton resources. Climate change may have previously unrecognized positive effects on freshwater copepod DHA content, body size, and fecundity in the small, shallow bodies of inland waters that are commonly found in north‐temperate landscapes.