Resource Management Exercise

I-20 Wildlife Preserve & Jenna Welch Nature Study Center

Congratulations !You have recently completed your study to become a resource management specialist. You first assignment is to evaluate the I-20 playa and adjacent wildlife preserve for the City of Midland and develop a management plan for the playa. Your work will be used to guide the restoration of the playa and to secure funding to carry out your plan. Your first job will be to evaluate the state of the playa. You will need to:

• identify the supporting, regulating, and cultural services of the playa,• identify three (two human caused) disturbances to the playa ecosystem, and• estimate the resilience of this playa ecosystem.

To undertake this first part, you will:• take a crash course in playas and complete the questions on pages 2-3 in your

journals, and • visit the four playa stations to learn about the I-20 playa in detail.

 To finish your assignment, you will apply what you have learned to suggest some management steps for I-20. To do this you will need to:

• prioritize the services that I-20 as an urban playa provides, and• suggest three steps to maintain or increase the functioning of this playa.

 GOOD LUCK and may Nature be your guide! 

So What is I-20?

I-20 is…

• a playa lake!• a protected area for

organisms and people.• a wet area in dry Midland• a rich center of

biodiversity• a wild place in nature• a place to visit over and

over again.

What do I need?

• Wear appropriate clothing: it could be warm, cold, wet or windy. Closed toed shoes are a must!

• Bring water, you will be there for a while!

• Remember the quieter you are the more you will see!

• Follow docent instructions.

WHAT IS A PLAYA LAKE?

Photo by Malcolm McElvaney

What is a Playa Lake?Spanish explorers in the1500’s called them Playas…Playa: Spanish for beach or shoreFrancisco Vasquez de Coronado and his men

described them as ponds, round like plates, a stone-throw wide or larger, some containing fresh water, and others salt.

Also called “Buffalo Wallows”Watering holes for native mammals Important hunting grounds for Native

Americans, early explorers, and settlers.

What is a Playa Lake?A naturally occurring

small, shallow wetland

Playa lakes average less than 30 acres and 1-2 feet deep

Contain water only seasonally, depending on rainfall

Due to the dry and wet cycles, they are a rich center for biodiversity

Photo by Nathan Knowles

Where are Playa Lakes and How did they Form?

Playa lakes in Scott County, Kansas (photo by William C. Johnson)

Where are Playa Lakes Found?Most playa lakes are located in the Great

Plains of…• Colorado • Nebraska • Kansas• New Mexico • Oklahoma• Texas

High Plains of Texas has the highest concentration of playas

Areas with playa lakes usually have long periods of drought– receive less than 20 inches of rainfall per year

How Did Playa Lakes Form?Playa Lakes form in generally flat land where a

watershed is present A watershed is the area of land where all of the water that is

under it or drains off of it goes to the same placeLow spots in the land collect water from rainfall

As the water flows into small caliche-lined basins, it brings with it organic materials

These organic materials break-down to form carbonic acidWhen carbonic acid meets the caliche (calcium

carbonate), the caliche dissolvesThe low spot sinks even lower, creating a playa.Clay particles eventually build up in the depression,

creating an impermeable layer which allows playas to retain water better than the surrounding land.

Why Are Playa Lakes Important?

Photo by Malcolm McElvaney

What Lives in & Around a Playa?Playa Lakes are rich

centers of biodiversityPlayas are typically the

home for… 200 species of birds9 amphibian speciesA minimum of 37

species of mammalsSeveral species of

reptilesA wide array of insectsMany aquatic and non-

aquatic plants

How Playas are Key to Bird SurvivalPlayas are critical stops along the central

flywayMigratory birds pass through Some birds winter in the playa

For birds, playas are the most important of all the wetlands.Provide an assortment of plants, insects, and

other invertebrates important to the diet of many different species of birds

Wet and Dry Stages–prevents diseases and bacteria in water

Birds that make stops in or live in playas tend to be healthier and have a higher rate of survival than birds that don’t.

Playa Lakes & the Ogallala AquiferThe Ogallala Aquifer is a 10 million year old

underground source of water underlying the great plains Reaches from South Dakota down to western Texas).The inhabitants of the Great Plains depend on the

Ogallala Aquifer as a source of fresh waterFarming irrigation accounts for 96% of the water usedThe levels of the aquifer are rapidly dropping

Hundreds of years ago, the aquifer water was naturally replenished, or recharged, by streams in the Rocky MountainsErosion has blocked the path of water from these

streams to the aquiferScientists believed the Ogallala Aquifer would be

completely drained by the end of WWII…

Playa Lakes Dry playas are the primary recharge bases for the

Ogallala Aquifer 80% of the recharge water for the Ogallala comes

from playa lakes

How does the Ogallala Aquifer still provide

water? Photo by Malcolm McElvaney

Protecting Playa Lakes

Photo by Wyman Meinzer

Threats to the Playa LakesAgriculture

FarmingCause: Many farmers see playas as an obstacle for planting cropsEffect: Playas are filled with dirt in order to make space for more crops

RanchingCause: Ranchers may see wet playas as a good watering hole for livestock Effect: The waste from livestock contaminates playas for plants and

animals, as well as polluting the water that recharges the Ogallala Aquifer

SedimentationCause: While erosion is a natural process, poor farming

practices and development result in eroded soils are also a large contributor.

Effect: Eroded soils are carried by water or carried in the wind and can fill playa lakes. This is the biggest cause for the loss of playas, leaving what are called “fossil playas.”

LOSS OF A PLAYA = LOSS OF BIODIVERSITY

Protecting the Playa LakesEducation is the answer to protecting these

rich centers for biodiversitySince most playa lakes are located on

farmland, land owners must be informed about how valuable playa lakes are, not only to migratory birds and other wildlife, but to all people who live in the Great Plains Region and depend on the Ogallala Aquifer as a source of water.

Encouraging playa-owning citizens to maintain the natural prairie grasses around the playa is the best way to avoid sedimentation and the formation of “fossil playas.”

Become Involved

What Makes Midland’s Playa Lake Unique?

Photo by Malcolm McElvaney

The I-20 Wildlife Preserve & Jenna Welch Nature Study CenterThe I-20 Wildlife Preserve & Jenna Welch Nature

Study CenterOur playa is in an urban setting, increasing

stressors on the ecosystem, including invasive species (ie. fish & cattails & bullfrogs & saltcedar), modification of hydrology and watershed, man-made inputs (trash, debris)

The I-20 is within city limits and is protected by the city.

It has increased diversity in wildlife due to the urban setting.

Higher concentration of wildlife b/c best place for them when it’s close to the city- wildlife safe-haven.

SourcesPlaya Lakes Joint

Venture Film: Playas, Reflections of Life on the Plains.

Playa Wetlands. Texas Tech University.<http://courses. ttu.edu/thomas/wetlands/>