Jennifer N Harding

PhD in Biology – Nutrient subsidies, food web dynamics and conservation


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Movers and shakers

Pink salmon return to their natal stream to spawn near Bella Bella, British Columbia.  Photo credit: Conor McCracken, CDM Images

Pink salmon return to their natal stream to spawn near Bella Bella, British Columbia.
Photo credit: Conor McCracken, CDM Images

 

Our paper, “Movers and shakers: nutrient subsidies and benthic disturbance predict biofilm biomass and stable isotope signatures in coast streams” got the cover of Freshwater Biology this month.

In a 16 stream study, we found that out of several variables considered to affect biofilm isotopes and biomass, salmon density and catchment size are among the most influential.

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From earth and ocean…

A recent paper by Joel M. Harding and John D. Reynolds found that the stable isotope ratios of Dungeness crab (Metacarcinus magister) are greatly affected by not only upstream salmon density but also by upstream watershed size and red alder (Alnus rubra), a nitrogen-fixing tree.  There were also larger crabs found below the largest estuaries.

The authors write: “These results confirmed that resource subsidies can constitute large proportions of the Dungeness crab’s diet, that crab abundance is determined by habitat size, but that crab size is affected by the magnitude of terrestrial resource influx.”

Find the paper here:  Harding, J. M. and J. D. Reynolds. 2014. From earth and ocean: investigating the importance of cross-ecosystem resource linkages to a mobile consumer. Ecosphere. 5(5): Article 54.