Aquatic Life in Our Haw River Backyard

At our new 36 acre private nature preserve along the Haw River near Graham, NC, there are a surprising variety of aquatic habitats and terrestrial communities affected by animals that live part of their lives in wetlands.  Aside from the river itself, there are shallow sweet gum swamps, deep gullies, shallow creeks, spring runs and ephemeral puddles that provide critical habitat for a wide variety of creatures, only a few of which will be considered here.

The Haw River had a considerable history of serious pollution during the early industrial revolution that led to building of textile factories.  Water power from damming of the river attracted these industries and they often dumped their toxic wastes into the river, turning the river a shocking variety of colors.  The good news is that early period of exploitation and pollution is mostly past although there are still periodic spills of toxic organic chemicals from plants built now throughout the watershed.  But what can we learn about the recovery of the river from those early days of mindless pollution.  The primary thing is that the river is now a thriving ecosystem despite not having water quality as clean as we would like it to be.

The Haw River at our location just upstream of the Union Bridge (below the Saxapahaw Bridge) varies between a shallow clear stream with very rapid increases in flow and turbidity coincident with rainfall.  There are many fish in the river including large mouthed bass, a top predator.  The presence of a healthy population of such top predators presupposes a healthy food web beneath.  However this food web is quite different from when the first European settlers arrived in the early/middle 1700’s.  The major factor is the presence now of many dams with no or inadequate fish ladders.  So the migratory anadromous fish such as shad and eels which were present in huge numbers are now absent in most areas of the river.  The importance of such migratory fish to the Indians prior to 1700 is indicated by the presence of stone fish weirs, one of which is found on our property.  Indeed there is a sub-canopy tree the shad bush or service berry whose spring blooms were approximately coincident with the arrival of the shad.  The alternate name service berry referred  to this time also being used to bury those who died during the winter and could not be buried in the frozen ground.

Many aquatic animals spend part of their life cycle in water and the rest on land.  Dragonflies and damselflies are common examples of this strategy to minimize competition between adults and aquatic larval forms.  Although many insects and arthropods live at least partially in water, there are very few spiders which do so.  The so-called “fishing spider” shown here walks on the surface tension of the water and can grab small fish and other prey which are under the water.

Of course amphibians such as frogs can live as adults on land and in water, and usually have larval stages in water.  The gray treefrog shown here is actually two separate but identical appearing sibling species that differ in chromosome count (Cope’s gray treefrog is diploid and the common gray treefrog – actually much rarer- is tetraploid).   The adults live on land/vegetation and breed in small fishless ephemeral ponds.  The adult green treefrog is amphibious and can live with fish but tends to be in smaller streams and ponds.  The American toad is terrestrial but breeds in tiny fishless wetlands.

The most obvious reptile/turtle in the river is the river cooter, often seen basking in large numbers.  The females are larger and the males have long fingernails to stimulate them into mating and a long tail/penis to make mating possible in such difficult circumstances.  Ogden Nash said it best- “I think it clever of the turtle in such a fix to be so fertile!”  Basking in turtles allows them to maintain a higher body temperature and digest plants which otherwise are relatively indigestible.

The most common river snake is the northern water snake which can grow to an impressive size but is completely harmless.  There are of course water moccasins present in fewer numbers especially in lower elevation backwaters/ swamps; their larger head and rotund body shapes are quite different, they have an elliptical pupil and an infra-red pit organ between the eye and nostril.  If you are not able to tell them apart do not touch any snake!

There are of course many birds associated either directly or indirectly with the river and river-side habitats.  Two of the most obvious are the great blue heron and the osprey.  The heron will eat not only fish but reptiles, amphibians and even mammals if it can catch them.  In contrast the osprey or fish hawk feeds entirely on fish.  This is such a successful strategy that the osprey is found world-wide and migrates long distances in winter.

The river itself is not a separate habitat but part of a complex series of wetlands and wetland-related communities that exist alongside the river.  Many of these wetlands are only wet during parts of the year and thus fluctuate between being terrestrial and wetland habitats.  Animals come and go depending on the seasonal presence of water.  River bottom-lands are also prime habitat for some wintering animals such as hermit thrushes and woodcock.  Bottom land trees can also be used for breeding habitat for warblers such as prothonotary and yellow throated.  You will find ample challenge in finding and identifying these animals and their plant associates any time of the year and it is a great deal of fun.