Short-billed dowitcher, a quintessential “mud bird.” © MJ Kilpatrickįinally, revegetating pools are used by colonial nesting gulls and terns that preferentially choose nest sites in wrack that piles against these tall grass areas in the marsh interior. It’s all about the worms! © MJ KilpatrickĪ semipalmated sandpiper caught a big one. That means that pool mudflats are the only available muddy habitat at higher tide stages when other areas are flooded and inaccessible. The muddy bottoms of the pools are perched at a higher elevation on the marsh compared with the mudflats of tidal creeks and sounds. When pools breach and become tidal, they are also foraging habitat for all of the above species and most importantly provide mudflat habitat for feeding shorebirds. Roosting willet and dowitchers © MJ KilpatrickĪll photos in this article were taken at actual marsh pools. When pools form and are non-tidal, they are used by aquatic life and are feeding habitat for ducks (particularly the dabblers), herons and egrets, terns and gulls and serve as roosting habitat for shorebirds.īlack ducks love marsh pools. In the case of pools, each successional stage likewise provides habitat for a different suite of wildlife. It is akin to the textbook example of succession which illustrates a cleared forest or beaver meadow that supports a different suite of wildlife at each successional stage as the spot proceeds from shrubs and grasses to young forest and on to old growth.ĭepiction of forest succession by andrea rothman Part two of my mind being blown by marsh pool dynamics was the realization that this successional process maintains habitat diversity for wildlife. The pool cycle as a driver of wildlife habitat Once I learned to read the landscape on aerial photos, I could see intact, breached and recovering pools all over the salt marsh (that is, in those places where the marsh has escaped ditching).Ī particular piece of marsh will have a range of pools at various stages in the successional cycle Often when a pool recovers to vegetation, a narrow tidal creek is left behind that bisects the former pool area. The pool formation and breaching process also appears to be linked to the development of creek networks. It’s remarkable that such a fundamental tidal marsh phenomenon eluded our understanding for so long. The earliest of these papers appeared in 2010. 121, 1391–1407.īy taking deep core samples the authors showed that a particular spot of marsh had alternated from being occupied by a pool, vegetated marsh and back again over time. 2016 Revisiting salt marsh resilience to sea level rise: Are ponds responsible for permanent land loss? J. 2014 Saltmarsh pool and tidal creek morphodynamics: Dynamic equilibrium of northern latitude saltmarshes? Geomorphology 213, 99–115. 2010 Probing the Origins and Stratigraphic Signature of Salt Pools from North-Temperate Marshes in Maine, U.S.A. 2009 Stratigraphic and ecophysical characterizations of salt pools: dynamic landforms of the Webhannet salt marsh, Wells, ME, USA. T., Croitoru, A., Dionne, M., Belknap, D. They showed that it is a successional process that has been occurring for at least a thousand years. These papers, for the first time, described the process of pool formation, breaching and vegetation recovery. Right about then I discovered a rich vein of research into this phenomenon on New England marshes. The breached pools were becoming marsh again. In less than 10 years since breaching, this pool has become mostly revegetated.Īs I spent more time with Google Earth I realized that pool formation and breaching was not a one-way street. And the dead-end basin of the pond allowed the sediment to settle and accumulate. The little creek that brought the tide into the pool over time also brought sediment. They were filling in with mud and revegetating. Over time I realized that my former hunting spots were continuing to transform. The answer, it turns out, is “not necessarily.” I asked myself, “Is this a sign of unprecedented change? Is sea level rise causing these pools to breach?” It is much less convenient to hunt on a tidal pond because one must always fret over the coming and going tide. I’ve lost some favorite duck hunting spots to pool breaching. At low tide the pool drains to a mud flat and at high tide it brims with water. When this happens the pool becomes tidal. It holds water at all times, perched in the middle of the marsh amidst winding tidal creeks.īut as I’ve visited the same places over the years, I’ve noticed pools enlarge until their sides intersect with a creek. A non-tidal pool (left) that was subsequently breached by a tidal creek (right)
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