EPOW - Ecology Picture of the Week

Natural Estuarine Mudflats, Southeast Alaska

Explanation:   As our noisy Beaver floatplane tilts into the morning sun, we find ourselves banking over vast mudflats here in coastal southeast Alaska.  Below, the river channels filigree into tendrils that look like  gargantuan dendrites of some impossible neuron.  

But this is just one of a plexus of river drainages that create vast mudflats along the bays and inlets and islands of the Alexander Archipelago that spreads along southeast Alaska.  

What good are mudflats?  Particularly here in the far north, mudflats provide essential habitat for wildlife ... including millions of shorebirds for feeding, resting, and breeding.  Mudflats also support vast numbers of invertebrates -- critical parts of the food web -- such as crustaceans, worms, water boatmen, mayflies, midges, moth flies, and many other species that feed birds and fish alike.  

Mudflats are wonderful environments for conducting scientific studies and discovering new and complex relationships among organisms and their environment.  For example, experiments have shown that shorebirds and crabs feeding in mudflats can significantly reduce the density of their invertebrate prey but in different ways and during different seasons.  And the shorebirds had their greatest effect when feeding in the muddiest mudflat but not in the sandiest mudflat.  

Mudflats are also more delicate ecosystems than they may first appear.  They are quite vulnerable to pollution, particularly from oil spills.  Ill effects of an oil spill can last for years or even decades as the oil seeps into the mud and sand. 
  

Information:
    Augustin, J. C., J. W. Grubaugh, and M. R. Marshall. 1999. Validating macroinvertebrate assumptions of the shorebird management model for the lower Mississippi Valley. Wildlife Society Bulletin 27(3):552-558.
    Masero, J. e. A., and A. Pacuterez-hurtado. 2001. Importance of the supratidal habitats for maintaining overwintering shorebird populations: how redshanks use tidal mudflats and adjacent saltworks in southern europe. Condor 103(1):21-30.
    Quammen, M. L. 1984. Predation by shorebirds, fish, and crabs on invertebrates in intertidal mudflats: an experimental test. Ecology 65(2):529-537.