Monday, May 26, 2014

Water Garden

The Water Garden has now been in existence for 14 years.  In that time, the composition of flora and fauna has been constantly changing.  I’ve tried to guide that change to create what I believe would be the ideal situation, but the Water Garden has proven to be a dynamic force that will not be tamed.

Water Lilies are the only introduction I made of plant species not found on the property.  Even these lilies don’t follow my original intent.  Planted in weighted pots, their root systems become so massive during the summer that they rise to the surface to float about as islands.  The root masses have totally engulfed the pots along with several bricks that I tied on in an attempt to keep the roots on the bottom.  Several species of aquatic plants have colonized the islands and survive the winter immersion while waiting for the islands to pop back to the surface in summer.

Water Lily flowers always fascinated me as a child.  I would spend hours staring at them.  This year, you have to view these white flowers early in the day to catch their brilliance.  Tree pollen is falling so heavily that white quickly turns to yellow as the day goes on.  The bud to the left has collected several rings of pollen already.  The pollen forms a skin on the water’s surface that remains until a rain causes it to sink to the bottom of the pool.

I put in some pots of native aquatic plants when the water garden first filled.  Since then, a variety of seeds has arrived to add diversity to the pots.  The actual lip of the pot is about an inch below the water surface.  Accumulation of moss, roots and organic debris has raised the soil level above the water line and doubled the diameter of the original pot.

Common Milkweed arrived on the scene just a few years ago.  Although I have several stands of milkweed around the yard, the plants growing next to the Water Garden are most favored by the Monarch butterflies.  Even though the plants become quite unruly later in the year and lean out to threaten visitors to the house, I’ll leave them to grow here.  With all of the reports of possible Monarch extinction, I would hate to deprive even one individual the opportunity to deposit some eggs.

Field Horsetail has now formed an almost solid border between the driveway and the Water Garden.  Along the creek, where I originally collected this plant, the horsetail grows in tiny patches and seems to be struggling to maintain a presence.  I was hoping it would maintain this same pattern in its new location.  Instead, it has set out on a campaign to claim as much territory as it possibly can.  If I didn’t keep it in check with a little glyphosate application, it would have taken over the driveway and half the yard by now.

I collected some rushes from the pond and installed them in pots on the back side of the Water Garden.  They have formed a floating mat that bridges the pots and extends into deeper water.  The floating roots are unable to keep the tall plants upright and the tops soon fall over.  Other plants have colonized the rush mats, including the invasive Narrow Leaved Cattail.  The one in this photo will be cut and sprayed.

The cattail leaves do make a sturdy support for a dragonfly nymph making the transformation into an adult insect.  Several species of dragonflies deposit eggs in the Water Garden and the discarded exoskeletons of mature nymphs are a common sight.

Being a permanent water body, the Water Garden has provided conditions conducive to the establishment of aquatic predators.  I no longer see explosions of tadpoles, crustaceans or insects, because the various established predators keep those species at lower levels.  Dragonflies are one of those predators.  This dragonfly skin may be empty, but you can still see the labium, or lower mouth part, used by the dragonfly nymph to capture prey.  The nymph extends the labium like a long arm to reach out and snag any creature small enough to hold. 

At the end of the labium is a set of curved hooks that trap the prey and hold it while it is consumed.  A pool full of dragonfly nymphs can easily cut down the number of smaller organisms.

Another predator with a never-ending appetite is the Red Spotted Newt.  These guys will feed on any animal matter, dead or alive, that is small enough to swallow.

In time, larger predators arrived.  The Common Water Snake feeds on the larger pool inhabitants, including other predators.

Bullfrogs have massive mouths and will try to eat anything that moves.  When Bullfrogs move into a small pool, they quickly consume the smaller frog species.  I’ve tried removing predators in an attempt to keep the pool in an earlier stage of development, but have decided that type of activity is not practical.  The Water Garden will be left to those species adapted to living in a permanent pool environment.  I will construct new pools with the proper conditions for the other species I enjoy so much.

The Water Garden still holds Green Frog tadpoles from eggs laid last year, but there are no adult Green Frogs left.  The tadpoles feed algae and other plant debris.  More tadpoles mean clearer water.  This tadpole has been skimming pollen from the surface.  I guess next year’s tadpoles will be those of the Bullfrogs.

Water Boatmen colonized the Water Garden before it had completely filled with water and have maintained a continuous presence since then.  These are true bugs with the signature tube-like mouth parts.  They feed primarily on algae and decaying organic matter.

Air is carried by the Water Boatmen as a film covering the body surface.  This gives the bugs a shiny appearance and makes it difficult to view body details.  They stay submerged by anchoring to stationary objects and periodically come to the surface to exchange stale air for fresh.

Great Blue Herons have eaten all of the goldfish, so the 100 gallon tub has lost its top predators and algae eaters.  Algae is a quality food item and where food exists, something will come along to eat it.

Since a population of new predators has not yet had a chance to colonize the tub, the Gray Treefrogs have a safe place in which to lay their eggs.  New egg clusters are placed almost daily.

The tadpoles develop quickly and it won’t be long until they are growing fat on the algae.  I’m looking forward to seeing what other changes this year brings to my Water Garden complex.

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