Life Along a Valley River: The Tuolumne

In days gone by, California's Great Central Valley was crisscrossed by a handful of free-flowing rivers carrying snowmelt from the Sierra Nevada to water fertile grasslands below.  Natural flood plains were regularly inundated with nutrient-rich silt, and wetlands of tule reeds and myriad wildlife flourished.  Today, the rivers persist in a somewhat diminished state, rigidly controlled by upstream reservoirs and dams.  Fruit and nut orchards, vineyards and housing developments have spread across the valley, to the very edges of river bluffs. 

The view west, down the Tuolumne River in Stanislaus County.

Earlier this year, flooding was a major concern in many areas along the rivers, the water flowing fast and strong.  But last year, like many years, the Tuolumne River was low and fairly calm, allowing for natural explorations of the riverine ecosystem.  Now, in the fall, the river has returned to its placid state.  When the river is quiet, pleasant hours can be spent wandering its banks and peering into the shallows.  Where the Tuolumne leaves the foothills and begins its journey across the valley to join the San Joaquin River, there are a few spots that have become special to me.

Damselfly resting along the edge of the Tuolumne River, a natural and beautiful part of this ecosystem.

 

Unfortunately the rivers of the Great Central Valley, which once offered life-giving abundance to wildlife as well as humans, have been greatly diminished and disrespected over the last century.  The rivers were manipulated, their natural cycles of flooding disregarded, their native vegetation uprooted and indigenous species supplanted by aggressive exotics. 

 

Bullfrog tadpoles lurk in quiet waters.  This introduced, invasive frog gets to be quite large as an adult and preys on
anything that will fit into its mouth, including native species of fish and frogs, even ducklings and turtle hatchlings. 
Bullfrogs are destructive to the native fauna and efforts have been made across the state to eradicate them.

 

I like to think that today, we have reached a turning point in our relationship with the rivers.  I like to think that we have learned our lessons and hence forth will do a better job of protecting our rivers and watersheds.  Many individuals and organizations do just that, and the results are encouraging.  But the sad truth is, our rivers are still corridors for invasive species, and their banks and beds still collect trash and bear the scars of careless humans.  

Why are our rivers so subjected to becoming trashed and polluted, these beautiful riparian ecosystems damaged beyond recognition? 

 

Purple Loosestrife: though beautiful, this introduced ornamental plant has escaped
gardens and now out-competes native vegetation along our rivers.

 

Where once grew Valley Oaks, there now grow almonds.  Riparian areas were once thriving ecosystems, multi-storied forests akin to tropical rainforests in their complexity.  Canopies of oaks and cottonwoods gave way to understories of willows and elderberries.  Thickets of native blackberry brambles and wild rose bushes formed a dense carpet beneath, and the whole assemblage was intertwined with vines of wild grape and filled with wildlife.  Today, these forests are very different, if not gone entirely. 

We can still find protected remnants of what used to be, though the glorious riparian forests have been largely replaced by a scattering of weedy non-native species: Tree of Heaven (Ailanthus altissima) and escaped ornamentals line the riverside bluffs, purple loosestrife and exotic annual grasses carpet the banks and water hyacinth chokes out life in the quiet waters.  Old tires, beer bottles, abandoned ice chests, rusty cans, broken flip flops, carelessly discarded fishing hooks and more yards of wildlife-threatening fishing line than I care to think about now fill our rivers and adorn their banks. 

 

Evidence that even in their diminished state, valley rivers do indeed support life!  This felled tree is evidence of beaver
activity.

 

I can only conclude that we have almost entirely lost touch with the river ecosystems that our predecessors, the former inhabitants of our valley, once knew so intimately.

 

Therefore a remedy to the current sad state of our rivers, or at least the beginning of their restoration, must come from a reintroduction to the wonders that are found in the life along a valley river.

Find a quiet spot to venture down to the river.*  Wade in the shallow water along the edge and watch tiny fish and tadpoles scurry out of your way.  Flip over a rock to examine the life beneath.  Follow raccoon tracks along the bank and watch quietly for otters and beavers.  (Beavers, while sometimes accused of being pests, are really great hydro-engineers, vital to a healthy ecosystem.)  Notice an osprey or hawk soaring above, a belted kingfisher calling loudly from its perch, acorn woodpeckers busily working in the oaks.  Black phoebes chirp from conspicuous branches, and during the summer months, swallows dart across the surface of the water catching insects on the wing.  If you're lucky, you might catch a glimpse of a Western Pond Turtle (California's only native turtle) basking on a log.  I've seen evidence of beavers, river otters, raccoons, foxes, opossums and even shrews along our rivers, and over 50 species of birds along just one small section of the Tuolumne River. 

Flip over a rock... and you might find flatworms!  Though not much to look at, these little guys are just one small part of
a much larger and immensely complex ecosystem.

To peer into a miniature world, take a closer look at the insect and other invertebrate life that abounds in and near rivers.  Dragonflies and damselflies are easily seen and recognized, but less familiar to many are their aquatic larvae.  Crayfish, though introduced in the valley, are fun to watch as well as catch.  Peek underwater for a look at the world beneath the surface, where bass and bluegill (introduced for sport fishing) swim along the rocky bottom.  In the fall, it's a fascinating thing to watch the annual salmon migration and spawning.

Beneath the surface, it's mesmerizing to watch bass, bluegill and other fish glide quietly through the water.  (Whoever said snorkeling is just for Hawaii?)



 

Perhaps slowly we will become reacquainted with rivers and the life found there.  First we may notice the singing birds, a jumping fish, an otter sliding quietly beneath the surface, and we will remember that the rivers belong not only to us.  Then maybe we will be moved to pick up a piece of trash, pull a few invasive weeds and clean up a jumbled tangle of fishing line.  Perhaps, one inspiring discovery after another, we will regain our collective appreciation for our precious rivers.

 

* Explore safely, and remember to be aware of your surroundings!  Rivers are always unpredictable.