Hidden Secrets of the Bosque

Drive around the tour loops at Bosque del Apache NWR (or any National Wildlife Refuge for that matter) and you're likely see a few side roads with little blue and white "Area Closed" signs.  What's being hidden back there?  Well, come along and find out!

These areas are closed to the general public for numerous reasons-- some are intended as "refuges within the refuge" (less stressful places where wildlife can get away from carloads full of nature-loving tourists),  other areas are closed due to habitat restoration (or degradation), sensitive areas for endangered or breeding species, or just the boring old "back-end business" areas of the refuge (where water control structures, equipment operations, or other such things are located).

As a volunteer ranger naturalist, I was fortunate to get frequent assignments to these closed areas of Bosque this past season, including driving a tour van each Saturday afternoon for the popular "Hidden Secrets of the Bosque" tour conducted by Bosque's senior volunteer naturalist, Cathie Sandell.

One prominent feature of central New Mexico's Rio Grande valley that visitors are surprised is so very "hidden" from view...is the river itself!

Historically, the river flooded and continuously altered vast sections of the valley, but by the twentieth century, upstream dams, reservoirs, and an extensive levee system was built to finally tame the wild Rio Grande.  Tamarisk (Salt Cedar) trees were also brought in from Europe to help preserve the reconfigured river banks and prevent soil erosion.  It all seemed like a perfect plan to help central valley farmers and ranchers prosper.

But progress came at a price.

The vast wetlands (that thousands of migratory waterfowl relied on each winter) dried up and was nearly eliminated.  This, in turn, dramatically reduced the numbers of ducks and migratory birds.

Land for Bosque del Apache NWR was purchased in the mid-1930's with a mission to create new man-made wetland areas and food sources for wintering duck populations.  The Civilian Conservation Corps (CCC) built the initial refuge buildings, pond impoundments, water control canals, and gates in the late 1930's.  When the Refuge opened in 1939, it was well on its way to becoming the primary winter destination for migratory waterfowl along the central Rio Grande valley.    

By 1990, the Tamarisk (Salt Cedar) was well on its way too....to overtaking every last inch of land between the levee and the river (as well as many other areas of the Refuge).  Rather than seeing a meandering river flowing through a diverse ecosystem, one currently sees this imposing line of impenetrable salt cedar--

The narrow, concrete-lined Low-Flow Conveyance channel runs parallel to the river's west side for about 100 miles through central New Mexico.  It began service in 1959 as a more efficient means of delivering water to southern New Mexico and El Paso.  The Refuge (and other central valley ranches and farms get their water from the Low-Flow as well).  

Along the channel's west (left) bank, habitat has been restored to native cottonwoods and coyote willow.  The goal is to now restore the levee (right) side and eliminate the final dense forests of salt cedar within the refuge boundaries. 

Somewhere out there is the Rio Grande....really, it's there!

One of my early assignments this Fall was to take some photographs for the Hidden Secrets tour to show visitors just how dense a salt cedar forest really is. I hiked one of the researcher transect "tunnels" (thankfully, after the coniferous salt cedar had shed its annual vegetation so there'd be some daylight to illuminate my path).

It was every bit as creepy as it looked--along this monoculture "tunnel," there was no sign of any other plant or animal life.

Light began to emerge at the end of the tunnel after half a mile, and I finally reached the banks of the Rio Grande. Yes indeed, the river actually does exist!

The Heavy Equipment crew at Bosque have spent, literally, their entire 20 and 30-year careers working to remove salt cedar from the Refuge.  In the 1990's and 2000's, they cleared it from the south end of the Refuge's south tour loop (where the John Taylor trail and cornfields now reside).

Recently, a final major project was launched to remove the final miles of salt cedar between the river and the Low-Flow Conveyance.  I got to tag along with the crew leader, Dennis, during the first week of the project.   This is a man with a plan (and some pretty impressive Caterpillar tractors that have been customized to take on these difficult trees).

This particular Cat has a rotary shredder that can level large areas of brush via quick circular swaths

Off to slay some dragons!

A second unit has a rotary drum shredder built into its front scoop allowing it to quickly mow down large salt cedar trees in its path.

To give a sense of scale, 6-foot-tall Dennis poses in front of some of the tall salt cedar to be cleared.  To make things even more difficult, the roots of these trees are buried a few feet below river silt, so once the trees are cut to ground level, they will have to excavate further down to remove all the roots. 

It seems like a monumental, never ending job to clear this impossible highly-invasive forest.  Leave just a few roots or branches behind, and a whole new tree crop could easily reappear in just a few short months.

I return a few days later to see impressive progress being made by the team.  I can't wait to see what this area looks like next year when I get back to Bosque!

Down a few miles south of the current active project, at the south boundary of the Refuge, is a small grove of cottonwoods basking in the sunshine.  Dennis' team cleared dense salt cedar from this area about 5 years ago and it is starting to regenerate nicely. 

Across the Low-Flow channel are earlier restored cottonwood groves now soaking up flood waters that mimic the river's previously natural wetland cycles.  What a legacy Dennis' team has left for so many future generations of wildlife (and people) to enjoy.  The ducks love these quiet, secluded ponds!

The Refuge's South Boundary gate was a highlight destination of our Saturday "Hidden Secrets" tour.  Non-tour visitors have to ride bikes or hike 6 1/2 miles down the Low-Flow road to see this gate (cars are prohibited).  Here, visitors can see the Refuge's southern neighbor (Ted Turner's vast 360,000 acre Armendaris Ranch) as well as the Refuge's main drainage canal (that returns over 90% of the water Bosque uses back to the Low-Flow, and ultimately back to the river).

Efficient water management is the Number One concern to this drought-prone refuge.  Bosque staff are constantly testing new techniques and food sources that can thrive in drought conditions.  In recent years, the Refuge has been moving from traditional corn crops (that require weekly watering), to native heirloom varieties and non-corn grasses (such as chufa/nut sedge) which can generate the same yields using far less water.

Prior to the start of each winter season, Refuge biologists calculate how many days worth of food is available for the ducks, geese, and cranes in each of the refuge's water units.  Then, they plan a schedule of when each unit will receive water during the winter season and for how many days.  This complex system allows them to stagger the food supply for the large wintering flocks, and plan when each unit will go dry again to regenerate next season's food supply.

The Refuge has also slowly upgraded a number of its old, labor-intensive screw gates with automatically-controlled, solar-powered Langeman gates.  The new gates allow water to flow more rapidly and precisely, meaning far less water consumed (or potentially wasted), and far fewer man-hours needed to maintain the gates.

Complicating the already-complex water management decision-making, has been the need to protect 3 small Federally endangered species found on the Refuge -- the Rio Grande Silvery Minnow, the New Mexico Meadow Jumping Mouse, and the Southwest Willow Flycatcher.

Rio Grande Silvery Minnow (web photo)

New Mexico Meadow Jumping Mouse (web photo)

Southwest Willow Flycatcher (web photo)

Nearly all river water previously diverted into the Low-Flow channel during the 1960's and 70's, leaving the main river virtually dried up in some spots of the central valley during Summer.

That all changed in the 1980's when the Rio Grande Silvery Minnow was listed as an endangered species.  Now, less water gets diverted and the main river remains flowing as often as possible.  While that assures the survival of the minnow, it means less water for the Low-Flow (which, in turn, means less water for Bosque and most of its neighbors).  Learning to live with less is key to survival in these parts of the West.

The New Mexico Meadow Jumping Mouse poses a different problem.  Only about 19 of these cute little guys exist in New Mexico, and they all live along Bosque's main water delivery canal. Until this year, water managers had to prioritize the needs of the mouse over the needs of water units within the Refuge.

But last Fall, a new stream bed was created parallel to the water delivery canal.  Come Spring, these muddy banks will begin to sprout grasses and soft, young coyote willows-- habitat the mouse absolutely loves!  Once this habitat is fully functional, biologist will re-locate the mouse population to this new stream-- thus making both the mouse, and refuge water managers much happier.

Like the mouse, the Refuge's last endangered species, the Southwest Willow Flycatcher, also loves coyote willow.  Except the flycatcher prefers much taller, older willows.  This often presented a real dilemma for refuge biologists-- should they cut the willow down to benefit the mouse, or let it grow taller to benefit the flycatcher?

During our volunteer training last Fall, the wildlife biologist took us through a tall strand of coyote willow to see one of the tiny nests used by the flycatcher the previous summer.   This particular area will remain growing and untouched as long as the flycatchers continue to return to these nests.

Saturday afternoons never ceased to reveal many hidden secrets of the Bosque.  Like this patch of salt on the ground (no, it's not snow!).  This is some of the lowest area of a valley that was once an inland salt water sea millions of years ago-- thus, salt still exists here!

One day, driving slowly past a grove of cottonwood trees, I found this skeleton (likely the remains of a mule deer)--

But, perhaps the most exciting hidden secret ever discovered was one Saturday as we drove a van-load full of visitors up the Low-Flow road.  A strange animal appeared across the channel up on the levee-- an Oryx.  Check out those horns!

These animals typically live on the east side of the river and over in the dry desert of White Sands Missile Range.  They were imported from Africa in the late 1960's by New Mexico Game & Fish for exotic trophy hunting, but having no known predators here, the Oryx population grew rapidly and is now quite a challenge to keep minimized.

Still, seeing this guy was a rare treat-- none of us in the van that day (including Cathie) had ever seen an Oryx in the wild before.  We were able to watch it for a couple of minutes because it could find no route in the thick salt cedar behind it to escape-- I guess salt cedar does have one benefit after all!

The capstone finale of Bosque's hidden secrets came just a few days before the end of my volunteer time.  Some current photographs were needed of the East section of the Refuge, and I was asked to come along with my camera!

This area (east of the river) is available to public use, but rarely visited.  After driving a few miles down dirt roads south of Highway 380 east of San Antonio, you come to a locked gate and sandy parking area.  From here, you can hike the 15 miles to the south end of the Refuge (one way), or ride horseback if you're a hunter in the right season licensed to hunt the right animal.

Thankfully, in our official Refuge truck, we were able to open the gate and drive the rough sandy road on this morning...

While one natural wetland area is visible, most of the East unit consists of sandy Chihuahuan Desert scrub.

Looking towards the Refuge from east of the river provides a whole new perspective--

After a bumpy 15 miles, we finally reached the south border of the Refuge and a short walk to the river along the fenceline with the Armendaris Ranch.

The popular "Point of Lands" Overlook off of Highway 1 south of the Bosque Visitor Center looks east towards Little San Pasqual mountain and what looks to be a flat-topped red lava mesa in front of it (at the mountain's left flank).

But once over to the East unit, this mesa looks entirely different!  It actually sits quite a ways off to the left (north) of Little San Pasqual.  And, it's actually not one mesa, but two!

The Piro Indians used to inhabit these mesas up until the late 1600's when the Spaniards traveled the El Camino Real (which passed through here from Mexico City to Santa Fe).

Look closely, and one can still find evidence of the Piros here, such as this petroglyph...

or this rock (likely once used for milling corn and grains).

Another secret was revealed along the north face of these rocks-- vibrant green and gold lichen!  Out here in the dry New Mexican desert!

From between the two mesas, I could see Socorro's M mountain off in the distance some 35 miles away.  What an incredibly different "secret" vantage point than those typically seen along the Bosque tour loops!

Visits into these closed areas made me appreciate all the important work (and foresight) that our Federal land managers do every day to protect and enhance our cherished public lands.  May their good work continue for many years to come!