Tuzigoot National Monument

Desert grassland surrounding the Tuzigoot ruins.  National Parks website photo.

When it comes to living off the land as the ancient Sinagua Native Americans did, Tuzigoot National Monument near Cottonwood, Arizona has it all.  Landscape diversity is essential when it comes to finding the products essential for life and Tuzigoot is especially rich when it comes to the landscape.  Think about it.  If you were to live off the land and not be required to wonder around searching for things constantly you would need a variety of different types of habitats that support a variety of different types of plants and materials necessary for life.  You would need food, building products for shelter, material for clothing, and water at least.  At Tuzigoot, all of these things are highly concentrated in a relatively small area. 

If you visit Tuzigoot National Monument you can see four major habitats that would have provided nearly everything the ancient Sinagua's would have needed within about 50 acres, which is about the size of a very small farm.  Tuzigoot is located in the desert grasslands of the Upper Sonoran Desert.  The desert grasslands surrounding these ruins would have provided yucca plants which provided some fiber and some food for the Native Americans.  Food would have been in the form of plants such as cacti fruits that could have been gathered or animals for hunting.  The desert grasslands are the least productive habitats though of this area.  Even more productive would have been the mesquite and acacia bosque downslope and closer to the river and wetland.  This thick brushy habitat grows where soil moisture is higher than in the grasslands and where the river has deposited deep soils.  The mesquite trees provide huge amounts of food in the form of mesquite beans every summer.  These bean pods were ground-up and made into cakes.  Mesquite wood also provided materials for building and tools.  The deep soils of the mesquite bosque are also likely where farming took place.  Of course, farming in these areas provided food mostly in the form of corn, beans and squash, but it also provided cotton to make clothing.  The mesquite bosque was also a great place for animals to hide and was therefore very good for hunting. 

Tavasci Marsh. Photo from National Parks website.

Slightly down slope from the bosque two extremely important habitats can be found.  The first is the large marsh.  The marsh is today known as the Tavasci Marsh and is dense with grassy wetland plants.  The marsh would have provided essential habitat for all kinds of animals that came to it for both water and food, both of which were scarce in the surrounding desert grasslands.  The Native Americans would have used the marsh as a hunting area as well as an area to gather food from plants.  For example, the cattails in the marsh provide huge amounts of potato-like food in their root systems.  Lastly, the perennial flowing Verde River would have provided trees for building materials, water to drink and for watering plants, and wildlife for eating.  Across all of these habitats there of course can be found an abundance of rocks that the Sinagua used for building. 

December Ephemeral Drainage Flow

A dry wash the morning after a flash flood came though.

The mid-December rain is the most reliable rainfall we receive here in the Sonoran Desert.  This rainstorm is almost like clockwork.  Every December, usually around the 15th or so, a strong Pacific frontal storm system brings rainfall in from the northwest.  One-half to one inch of rain pretty much falls across the entire desert with higher totals in the mountains.  Of the past ten Decembers, only one failed to produce any rainfall and that was during one of the driest winters on record in Arizona.  This year was picture perfect with one-half to one inch of rain falling in the Sonoran Desert between December 13th and 15th.  With this rain being almost like clockwork, the flow of the normally dry washes also flow during this rain almost like clockwork.  This year was a little odd in that the rain was spread out over a three day period making flows a little weaker than normal.  Typically, dry washes require a significant amount of rain over a short period of time in order to generate enough runoff to supply a flow.  A lot of drainages did flow at least a little though. 

Of course, a lot of rain over a short period of time helps these washes to flow in the desert, but there are other factors involved also.  Geology, or geomorphology, are probably the most important factors in determining flow.  Geomorphology is simply a scientific term that describes how landforms came about and how they function.  One of the functions of geology and geomorphology in the landscape is to determine how and where water flows.  For example, shallow unbroken bedrock is going to prevent water from seeping down into the soil and therefore will result in greater amounts of runoff.  Type of soil also matters in the amount of runoff produced.  Rain seeps very slowly into clay soils so a lot of runoff can be generated.  Sandy soils however can quickly absorb a lot of rain so not much will runoff.  Number of rocks also makes a difference.  Soils with fewer rocks have more runoff than soils with more rocks.  Rocks on a soil surface slow the speed of runoff and with slow speeds of runoff the water has more time to be absorbed into the soil.  Size of the dry wash also makes a difference with smaller washes flowing more frequently than larger washes.  However, larger washes tend to run longer than small washes when they do flow.  Larger washes simply need a lot more water to flow. Depending on the combination of these factors some washes will flow a few times annually while others will only flow a few times a decade.

All of these things factors also determine what lives where along a dry wash.  Flow is normally very short in duration in a wash.  This is simply because flowing water quickly is lost as it is absorbed into the sediments of the stream bed.  Though flowing water is lost, the water is not entirely lost.  Water is stored in these sediments for long periods of time after surface flow ends.  Depending on the depth of this moisture and the depth of the sediments differing plants will occupy the area.  Typically, deep sediments with relatively frequent flows will be occupied by blue palo verde and desert willow.  Areas of fewer or shorter flows typically have yellow palo verde.  Other plants such as acacia's, ironwood, wolfberry, and mesquites can be somewhere in-between. 

Montezuma Castle National Monument: Montezuma's Well

Montezuma's Well, part of Montezuma Castle National Monument.  This is the well viewed from the cliffs surrounding the pond.

The Montazuma's Well portion of Montezuma Castle National Monument is the lesser known of the two sections of the park.  It has far fewer visitors every year, but I personally find this section far more interesting.  First of all, the "well" itself is pretty interesting.  This "well" is simply a hole in the ground pond, quite an unusual landscape feature and I know of nothing quite like it.  This pond is located on a hill top that caved in as water dissolved away the limestone bedrock forming the hill.  Nearly vertical cliffs line all sides of the pond and there are well over 100 stairs down into this hole along the trail.  Ancient Native American ruins are built into many of the cliff walls around the pond.  If you think about it, this would have been quite a nice place to live 1000 years ago or so.  At least compared to the surrounding desert.  The surrounding Upper Sonoran Desert is similar to what is found at the Montezuma Castle portion of the National Monument, however, it is slightly higher elevation.  This means it is slightly cooler and receives a little more rain, just enough to support Juniper trees in addition to all the other plants found in the desert we discussed in our previous post.  While Junipers do add another food source, a little more shade, and a source of materials, it still doesn't make living out in the open desert possible.  Within the "well" area, the pond moderates extreme temperatures, supports trees that provide shade, and provides water.  All this making for a nice place to live during ancient times.  Every time I have visited the well in the summer though, I still think it would be an unbearably hot place to live.   I have noticed the cliff walls where the ruins are located are considerably cooler though.  Hanging out in the cliff walls during the heat of the day was probably a major way ancient inhabitants avoided the heat. 

Montezuma's Well at the outlet, where the pond flows into one of the surrounding cliffs.

If you aren't at least sort of amazed just by the landscape structure of the well, than hopefully learning about the aquatic biology of the pond itself will amaze you.  The biology of the pond is truly weird, almost sci-fyish.  First of all, because the spring that feeds the pond come out of limestone there is a huge amount of carbon dioxide dissolved in the water.  This does not mean the water is poisonous, but does mean that fish cannot live in the pond.  Which would have been a bummer to me if I was an Native American living there 1000 years ago.  Algae, however, thrive on the abundance of carbon dioxide.  This algae supplies food to loads of amphipods, which are sort of like tiny freshwater shrimp.  At night time, huge numbers of non-blood sucking leaches migrate towards the surface to feed on the amphipods.  It is rather creepy imagining a mass migration of leaches swimming towards the surface. 

Vegetation along the canal the empties into Beaver Creek.

Once outside of the well, the trail also takes you down a cliff opposite the pond cliffs and along Beaver Creek.  This is actually my favorite section of the entire monument.  As mentioned before, water flowing out of the well flows into one of the cliffs surrounding the pond.  On the other side of the cliff, the water flows out of another cliff along the creek.  This water enters Beaver Creek in a truly beautiful desert oasis.  This area is very wet and shady.  Temperatures are far cooler here in the shade and thick vegetation.  Huge Sycamores and Ash trees fill the area.  The area has enough moisture to support beautiful Columbine flowers and even some poison ivy, so watch out.  This verdant green area is quite a refuge from the surrounding harsh desert landscape.  

Louisiana Wetlands and the Mississippi River Delta Part 2

A floating Louisiana marshland.  This wetland is characterized by thick mats of semi-floating grasses, sedges, rushes, and a few small shrubs and are important to alligators for hibernation   

Also within these areas is the famed alligator of the south.  The abundance of water and bird life of these swamps and marshes feed these gators, allowing them to grow to large sizes.  The wild gator grows about one foot a year until it reaches six feet, then growth slows considerably.  The longest lived gators can survive up to 90 years in extremely rare instances and reach 15 feet in length.  Gators over six feet are uncommon but gators less than this are often found in abundance.   During warm summer months when water temperatures are over 70 degrees gators can be found throughout the swamps and marshes, anywhere there is enough water.  However, in November water temperatures drop below 70 degrees and gators go into hibernation until early spring when the water warms up again.  Typically, water levels in these wetlands fluctuate with ocean tides and floods coming from upstream.  This is a problem for hibernating gators who need to hibernate in wet areas but cannot be submerged with flood waters.  Because of this, gators hibernate in floating grassy marshlands that float up and down with fluctuating water levels.  Gator hunting is a rather common practice in Southern Louisiana.  The game management agency allows one gator to be harvested per twenty acres of wetland.  I've been told this is a major meat source for rural Louisianans.  I personally have eaten gator fried, as jerky, and as sausage.  Fried gator is rather chewy, but the jerky and sausage are great.  I love both of them.  In-fact, I may like gator jerky better than beef jerky.

A Louisiana alligator found in a bayou.  

Underneath all these wetlands in the sediments is an abundance of oil and natural gas.  Over past decades these natural resources have been drilled and mined out of the sediments, resulting in the wetlands sinking and flooding with more water.  This flooding has killed wetland vegetation and caused the disappearance of  this habitat.  According to some sources an entire football field of Louisiana wetland is disappearing as a result of this every 38 minutes.  Historically, the Mississippi has also snaked its way back and forth across southern Louisiana depositing sediments in low laying areas everywhere it went.  Today, the Mississippi is highly channelized and controlled by the Army Corps of Engineers, preventing this nature controlled movement and deposition of the river.  So when wetlands sink, sediments from the river is not available to raise them back up again.  People from all professions and industries are still searching for solutions to this problem.

The red area of the ocean indicates areas of low oxygen known as the dead zone.  This dead zone is a result of  water pollution brought into the gulf by the Mississippi River.  Picture from Wikipedia.

As the muddy waters of the Mississippi pass through the Midwest and the South, some of the richest agricultural land in the world, sediments and fertilizer are washed into and pollute the river.  The vast wetlands of the Mississippi River delta capture much of this pollution.  As wetlands naturally do, they capture and filter out pollutants from water in an amazingly efficient manner.  However, as some of these wetlands disappear, and being the levels of pollution are so extremely high, much of the pollution works its way through the delta and is deposited into the Gulf of Mexico.  This immediately has the effect of "fertilizing" the Gulf, which may seem a good thing at first.  Fertilization of water by pollution is known as eutrophication, and results in large algal blooms.  Once this algae dies however, the decompose and consume all the available oxygen in the water.  As a result of these low oxygen levels, very little ocean life can survive in these areas, giving it the name "dead zone."  The dead zone in the Gulf where the Mississippi ends currently is the size of New Jersey and has had huge effects on sea life, including the fishing industry.

Sediment pollution causing the dead zone (right side) next to oxygenated waters (left side).

Despite the negative, the wetlands of Southern Louisiana are still a vast, amazing, and relatively healthy functioning ecosystem.  Even in their impaired state these wetlands are still intact and functioning as they should.  Of course, they could function better if the Mississippi was allowed to flow as it pleased rather than be controlled.  With the many towns and small settlements in the area, letting the Mississippi flow back and fourth across the delta would likely destroy many of these communities.  Controlling the Mississippi is also important to the shipping industry.  So simply restoring natural flow is not such as simple task.  Still, even in their present state these wetlands absorb and filter much of the pollution that is carried down the Mississippi as well as provide huge areas for wildlife and recreation.  Without these functions the current dead zone in the gulf would be much larger and have enormous impacts on the fishing industry.

While I was only able to spend one day exploring these wetlands, it made me hungry to experience them more.  These wetlands are an amazing place to which so many people, cultures, plants, birds, and animals call home.  All of these different aspects are tied together forming the diversely rich creole culture.  In the near future, I will be talking more about this creole culture with a post about a historic Mississippi river plantation.

Louisiana Wetlands and the Mississippi River Delta Part 1

A Louisiana bayou in the Mississippi River Delta.  

Louisiana boasts an amazing 40 to 45 percent of the continental United States wetlands.  Flying into, and driving through Southern Louisiana gives you a good sense of the vastness of these wetlands, miles and miles of unbroken soggy earth everywhere.  Water is literally everywhere, there is of course lots of open water, and where there isn't open water there are sopping wet grassy marshes, and where there aren't mashes their are soaked forests.  The air is always full of humidity with a faint marshy smell, no matter where you are at.  I have visited many wetlands in my life, but none compare to the expansiveness and diversity of these subtropical wetlands.

A part from the sopping wet nature of southern Louisiana, the next most obvious feature is the perfectly flat nature of this landscape.  This soaked flat landscape is a result of the Mississippi River reaching the Gulf of Mexico and depositing massive amounts of water and sediment as the river slows before dumping into the ocean.  The Mississippi begins as a small clear stream at Lake Itasca in Northern Minnesota, which I have personally walked across in only a few short steps that only went up to my knees.  Growing up, I also fished the Mississippi River in Iowa where it is a mighty and muddy river.  Flowing southward, the river continues to grow in volume and accumulate more muddy sediments making it "The Big Muddy."  All this water and mud however has to end up somewhere and is deposited in a delta entering the Gulf of Mexico in southern Louisiana.  This deposition and delta forming process has been taking place for thousands of years since the end of the last ice age.  The entirety of Southern Louisiana was at one time deposited by the Mississippi, and today, over one mile of sediment covers the underlying bedrock.

Oak trees draped with Spanish Moss along a higher, drier portion on a bayou.

Along the Mississippi and other distributary rivers flowing out of it, heavier sandy sediments are deposited along the bank.  These sediments form a sort of natural levee elevated above the rest of the alluvial plain.  On these natural levees many species of oaks are commonly found including the Southern Live Oak, Water Oak, and Swamp Laurel Oak.  These Oaks can only tolerate temporary flooding and need to be on dry land adjacent to lots of water, such as next to a river or swamp.  A short distance from the river, the natural levee slopes slowly down, away from the river.  As the slope moves downward, away from the river, the ground becomes increasingly wet.  Maples and Ash grow on this wetter back-slope along with some oaks.  Lower on the back-slope the ground becomes increasingly saturated, often with standing water, here Baldcypress and Water Tupelo grow.  These areas are still high enough on the slope so that they are not flooded for extended periods of time.  Cypress trees can grow for over 1000 years on these sites and grow large "buttress" roots around the base of their stump in order to stabilize themselves for these long periods of time in these soggy loose soils.  All of these trees are draped with often thick clumps of Spanish Moss.  This moss, is technically not a moss at all but rather more closely related to a pineapple, very odd considering they look nothing alike.  These draperies of Spanish Moss are normally tan colored, except for after rainfall when they turn green.  Hanging from trees and blowing in the wind the moss gives the narrow bayous a romantic southern feel, as they decorate the majestic oaks and cypress trees.

Baldcypress trees found in wetter portions of the wetland then the oaks.  

A floating marsh wetland characterized by grasses, sedges, and rushes.  These types of marshes are important locations for alligator hibernation.

Away from the natural levee and closer to the mouth of the river where the water is always flooded, floating marshlands exist which are dominated by grasses, rushes, sedges, and cattails.  Historically, these floating marshes were far more common and widespread.  As they were settled, channels were dug through these marshes and the sediments piled adjacent to the channel.  These new channels formed what are known today as bayous with the adjacent piles of sediments forming vegetation similar to the natural levees along rivers.  These marshes and bayous can have brackish water (slightly salty) or freshwater and are filled with an abundance of life.  Brackish waters have crabs, while crayfish are found in fresh, both of which are trapped for the great seafood the area is known for.  Bass, crappies, drum, gar, and catfish are in abundance in these areas.  A guide told me there are so many fish in these wetlands that if you don't catch any fish, you don't tell anyone.  In other words, there are always fish to be caught, and to not catch any is not typical, and embarrassing.  Birds also fill these areas including waterfowl of all types, herons, and ibis.

This concludes part one of the Louisiana Wetlands.  In our next entry we will cover the famous alligator of these wetlands as well as some of the ecological issues they face today.