Apr 22, 2014

All dry below ...

Except for the alligator hole

Can you see it?

Apr 21, 2014

Perfectly-timed rain

It's often not how much ...

But when you receive dry season rain.

The above chart shows the history of April rainfall totals for Big Cypress National Preserve from 1970 to present

April is a perfect case point.

No rain in April almost always spells drought. Evapotranspiration (left alone) is just that strong. Last year saw record April rain (around 5 inches). This year so far we've recorded just under two. That's not enough to re-flood the swamp, but it is just enough to help keep deep drought at bay.

Apr 20, 2014

Giant-sized knee

This particular knee was big enough ...

That it almost looked like a tree stump.

This knee was almost
three feet tall and
tree-like wide at
its base
Apparently one of mechanisms by which  knees form is cypress roots growing around old tree stumps, possibly for nutrients or stability, but not for oxygen -- although the jury on their role in exploiting other atmospheric gases is still up in the air.

Apr 19, 2014

Water's edge (on the move)

Can you see the difference in these two photos?

They show the same cypress knees snapped two weeks apart.

Earlier in April
Ten days later


Look in background.

Apr 18, 2014

How To: End a drought

Sometimes all it takes
is one good April rain

As happened a few year's back

Apr 17, 2014

Water table "free fall"

It almost felt like the wet season out there today,

Afternoon showers were popping up left and right.

The above hydrograph shows a wetland water depth summary for Big Cypress Nat'l Preserve.  The solid blue line indicates water depth from 2012 to present.  The horizontal color coding indicates the ecological thresholds for major vegetation communities in the swamp, from bottom to top: dry season refugia, pond apple and marsh, cypress domes and strands, dwarf cypress marl prairies, and hydric and mesic pines.  The variable shading (i.e. dark to light) show the historic statistics and range, as measured from 1993 to present.The dotted white line indicates the long-term median level, as calculated from 1993 to present.  Currently, water levels are low, but pretty typical for this time of year.  That means that surface water is mostly absent except for the deeper areas (i.e. domes and strands) where the peat remains moist.    

But don't count on them to last.

The swamp water table has dropped 8 inches since the beginning of April. And chances are it will continue to drop in the weeks ahead.

The hydrograph matches 
what we see on the ground:

Dry but moist in the deepest holes,
with puddles of water becoming
increasingly harder to find.

Not that you'll be able to see it:

In most places it's now under the ground.

Apr 16, 2014

It's not always wetter on the other side

We know its dry in the pinelands,

But how dry is it in the low-lying neighboring domes?

Outside of dome (right) looking in

In this case, dry too.

Or almost dry.

Inside dome (center low spot) looking up
In not too long the puddle above could turn into cracked peat.

Apr 15, 2014

Dry as "chips and salsa"

Drought has descended on the swamp.

Pools have receded to the point that even the lowest spots are dry.

The chart above shows drought levels in the Big Cypress and various parts of the Everglades.  The black arrow shows current drought level, the dark gray arrow a month ago, the light gray arrow a year ago and the dotted red line the long-term average for today.  In general, the Everglades -- with the exception of WCA2 -- remains soggier than the swamp.

This is what I like to call "chips and salsa" drought season. What was once (i.e. in the summer) soggy periphyton is now hardened and cracker thin -- not good for eating but crunchy in the marl prairie when you step. As you venture into the domes or strands -- the deep ones at least -- you will still find shallow pools of water in the deepest spots, but those bowls of salsa are vanishing fast. I had heard an El NiƱo was forming and could bring us some late wet season rain.

Even spot showers would help.

As dry as "chips and salsa" may appear, the presence of the water table close to the surface helps keep the peat in the low spots moist.  That can act as a fire break to a degree and also dampen the incursion of hot flames into those areas should a fire occur.

That's not the case with the popcorn drought level one step below.

Apr 14, 2014

Rapidly vanishing water

Water levels were holding up all winter,

But suddenly they are dropping fast.

Only the deepest spot in this dome was still holding water.

Cardinal plant

Unlike orchids, bromeliads
are conspicuous and large

Apr 13, 2014

The plant that couldn't stand still

As stationary as plants can seem,

In actuality they are stealthily on the move.

Don't confuse the flower from the leaves

Take for example the cardinal plant above.

Can you see it growing a flower (albeit very small)?

Plants are born and die in the same spot.

But its progeny are poised to travel far.

Cardinal plants are a common bromeliad in the swamp

Just add wind!

Apr 12, 2014

Faka Union in reverse

The saltwater side (right) is higher
than the freshwater side (left)