| Darren M. Ward | Department of Biological Sciences |
| Dartmouth College |
Contact:
darren dot ward at dartmouth dot edu
I do research in basic and applied aquatic ecology. My primary research interests are population dynamics, predator/prey interactions, and trace element cycling in food webs. Most of my research has a strong field work component because that's the fun part of ecology!
Recent and ongoing projects:
- Mercury accumulation in stream food webs
- Atlantic salmon restoration
- Eurasian watermilfoil biological control
Mercury in streams
 Mercury
accumulation in fish is an ongoing problem. We
developed a unique approach to measure standardized mercury
accumulation rates for free-living fish in New England streams.
In spring, we stock juvenile fish from a uniform source population in
multiple streams. The fish then grow and accumulate mercury over
the growing season. In the fall, we collect samples to measure
mercury concentrations. We have applied this approach to identify
important ecological determinants of mercury accumulation in stream
fish. |
Relevant publications:
Ward, D.M., K.H. Nislow, C.Y. Chen, and C.L. Folt. 2010. Rapid, efficient growth reduces mercury concentrations in stream-dwelling Atlantic salmon. Transactions of the American Fisheries Society 139:1-10.
Atlantic
salmon restoration
|
|
Atlantic salmon were eliminated from the
Connecticut River basin in New England about 200 years ago when dams blocked
their spawning migrations. Now, we are trying to reestablish an
Atlantic salmon
population in the Connecticut River. My dissertation research addressed factors that limit survival and
growth of reintroduced juvenile Atlantic salmon in Connecticut River
tributaries.
Some of my dissertation work examined the effects of slimy sculpin on
juvenile Atlantic salmon survival. These small, inconspicuous
fish turned out to be important predators of stocked salmon fry. |
Relevant publications:
Ward, D.M., K.H. Nislow, C.L. Folt. 2009. Increased population density and suppressed prey biomass: relative impacts on juvenile Atlantic salmon growth. Transactions of the American Fisheries Society 138:135-143.
Ward, D.M., K.H. Nislow, and C.L. Folt. 2008. Predators reverse the direction of density dependence for juvenile salmon mortality. Oecologia 156:515-522.
Ward, D.M., K.H. Nislow, and C.L. Folt. 2008. Do native species limit survival of reintroduced Atlantic salmon in historic rearing streams? Biological Conservation 141:146-152.
Ward, D.M., K.H. Nislow, J.D. Armstrong, S. Einum, and C.L. Folt. 2007.
Is the shape of the density-growth relationship for stream salmonids evidence
for exploitative rather than interference competition? Journal of Animal
Ecology 76: 135-138.
Eurasian watermilfoil control- research
page at the University of Minnesota
Eurasian
watermilfoil is an exotic aquatic plant that can take over lakes. A
native North American aquatic beetle, the milfoil weevil, eats Eurasian
watermilfoil and sometimes
suppresses watermilfoil infestations. Unfortunately, the weevil
does not contol
watermilfoil in most lakes. My research tested whether fish
predation limits weevil populations. I used a combination of
field experiments and population
monitoring to show that predatory sunfish can prevent weevil
populations
from becoming abundant enough to control watermilfoil. So, by
suppressing the herbivorous
weevils, sunfish may facilitate watermilfoil infestations in lakes.
Relevant publications:
Ward, D.M. and R.M. Newman. 2006. Fish predation on Eurasian watermilfoil (Myriophyllum spicatum) herbivores and indirect effects on macrophytes. Canadian Journal of Fisheries and Aquatic Sciences 63: 1049-1057.