1. Salt Marsh Restoration
Role of Animals
Felicia Woods

2. Role of Animals
Animals are important to the processes occurring in salt marshes, and can be key indicators (or causes) of an unhealthy marsh. Bioaccumulation of toxins can reduce populations (e.g. DDT interferes with calcium deposition) There is an upper limit of population density that marshes can support.
DDT Now banned but an example (pg 156 shumway): Breakdown product of DDT is DDE, which is stored in fatty tissues. Calcium deposition in bird eggs

3. Animals Common to Salt Marshes
Mollusks
Arthropods
Razor Clams
Fiddler Crabs
Ribbed Mussels
Purple Marsh crab
Quahogs
Burrowing shrimp
Soft shelled clams
European Green Crab…
Coffee bean snail
Vertebrates
Whelks
Mummichog
Periwinkle…
Diamondback Terrapins
Polycheates
Sparrows, Shore birds, and Gulls…
Clam Worms
Insects…
lugworms…
LOTS!!!

4. What is known in the context of salt marsh
Studies have been conducted to test the importance of animals, both vertebrates and invertebrates, in salt marsh ecosystems.
Trophic Cascades
Bottom-up
Top-Down
Importance of biodiversity
Adaptations
Behavioral and physiological
Silliman and Bertness (2012)

5. Trophic Cascades Top-Down Effect Consumer impacts on herbivory
Silliman et al study on periwinkle population density
Overexploitation of top predators or keystone species
But wait!!! There could be hope…
Bottom-Up Effect
Resource availability
Degraded resources affect animal poplation
Grazers can limit primary production
Silliman results: effect different in different zones (low- form reduced by 88%, tall-form reduced to mudflat)

6. Biodiversity
“The most unique feature of Earth is the existence of life and the most extraordinary feature of life is its diversity” (Cardinale et al, 2012)
Healthy Marsh ecosystems support biodiversity
Many shorebirds and fish depend on marsh habitats for essential food supplies and nursery grounds,, as well as take refuge from larger preditors.

7. Adaptations
“Great changes in conditions occur in the salt marsh and many organisms are not adapted to cope with such changes. “ John Teal
Physiological
Osmotic equilibrium: e.g. salt excretion glands (birds)
Temperature regulation
Closable shells
Primitive lung (fiddler crab)
Behavioral
Burrowing
Zonation (aquatic group stays near low tide zone)
OB: diffuse salts into or out of body… think of lugworm example below
Most marine Animals can deal with differences in the concentrations of individual salts but cannot cope well with dramatic changes in the total concentrations of salts in their bodies.
e.g. lugworms swell when more freshwater flows into the system from rain and slowly leaches salts of its body to reestablish equilibrium
Shells: prevent desiccation

8. Importance in Salt Marsh Restoration
Top down consumer control of herbivores
Sustainable fishing (recreational and commercial)
Controlling top predator densities
Healthy population densities of key species indicate healthier system.

9. References
Altieri, A., Bertness, M., Coverdale, T., Herrmann, N., & Angelini, C. (2012). A trophic cascade triggers collapse of a salt-marsh ecosystem with intensive recreational fishing. Ecology, 93(6),
Cardinale, B., et al (2012). Biodiversity loss and its impact on humanity. Nature, 486,
Shumway, S. (2008). Salt Marshes. In The naturalist's guide to the Atlantic seashore: Beach ecology from the Gulf of Maine to Cape Hatteras. Guilford, Conn.: Globe Pequot Press.
Silliman, B., & Bertness, M. (2002). A trophic cascade regulates salt marsh primary production. PNAS, 99(16),
Teal, J., & Teal, M. (1969). Marsh Animals. In Life and death of the salt marsh,. New York: Ballantine.