Dune Plan Adaptations

Plan created by 2000 HOST Teacher Michael Collins.

Objective

Students will touch Coal Oil Point Reserve locating the species of plants that are on the handouts and describe the different adaptations used by plants in their specific area of the dunes.

This lesson plan includes a diagram/worksheet for each plant. Click here to download. (Diagrams by Elaine Miller Bond, worksheet text by Colleen Millions).

Grade level: 7 to 10

Introduction

A sand dune is like a little island of life. Plant adaptations help the plant survive in this harsh dune environment. Hot, dry conditions and the dune-forming winds of this area make it difficult for plants to survive, since they are being constantly sand blasted and buried. There are not many species of plants that can live here, and in this activity we will be working with ten of them from the three different dune areas. Coal Oil Point Reserve has over 40 acres of dunes.

Embryo Dunes

As you head inland from the ocean the first dunes you encounter are the embryo dunes. These dunes are small and no more than one foot high. They form when wind carries sand to a kelp wrack, or a germinating seed grows into a plant and the sand piles up around it. Typical plants in the embryo dunes include:

Beach-bur (Ambrosia chamissonis): This plant has a long tap root that helps it get the water it needs in this harsh environment. It’s also quite large and can cover a large area due to its long branches, so that if it’s buried, part of it will survive.

Sea Rocket (Cakile maritima): This plant has seed pods that float and look like little rockets. This is a dispersal mechanism that enables them to colonize a new area quickly by just floating in on the next wave.

Beach morning-glory (Calystegia soldanella): This plant has a large black seed that also floats and is a succulent, which helps retain moisture. It does not have any hairs on the leaves.

Foredunes

The next set of dunes up the beach from the embryo dunes are the foredunes, which are unstable dunes. These dunes remain in the same place but change shape. They are slightly larger and have been around longer than the embryo dunes.

Plants in the foredune areas are prostrate to the ground due to higher wind speeds. Their seeds tend to float for dispersal reasons and more of them are succulents. Long tap roots and leaf glue are adaptations to a harsh environment. Sticky leaves trap sand, which stimulates hair therefore increasing the surface area, which helps retain moisture. Beachbur is the most common plant in the unstable foredunes. Other foredune plants include:

Red sand verbena (Ambronia umbellata): This plant is found above the high tide line. It has dark pink flowers and leaf glue that traps sand.

Beach primrose (Camissonia cheiranthifolia): This plant has yellow flowers, and the leaves have a bluish color due to the hairs that help retain moisture. It has very small black seeds located in a pod.

Salt grass (Distichlis spicata): This plant is found everywhere but mainly grows on the edge of the estuary. It has a light green color and produces mainly light brown seeds.

Backdunes

The diversity of plants generally increases as you go from the foredunes to the backdunes, which are stable dunes. Backdune plants are usually more erect. They have adapted the ability to conquer new habitats quickly following a disturbance by producing lots of small seeds. Backdune plants include:

Telegraph weed (Heterotheca grandiflora): This plant is about a foot tall and found near the fault. It has hairy, light green leaves and yellow flowers on top.

Bush lupine (Lupinus arboreus): A member of the pea family, this plant is dark green in color and has pods where it keeps the seeds. The leaves are in the shape of an asterisk.

Goldenbush (Isocoma menziessii): The coastal goldenbush has golden-yellow flowers and serrated leaves.

Coyote bush (Baccharis pilularis): This sticky shrub has dark green leaves and can grow prostrate or erect.

Location

Coal Oil Point Reserve

TIME REQUIRED: The Dune Plant Identification could be completed successfully in as little as 25-30 minutes. It could also be extended to allow time to identify other species in the area. Allow another class period for discussing results and possible adaptations.

Teacher Preparation

Before the trip, spend some class time on classification of plants and include the information that is on the instruction sheets. It is important that students can distinguish the different characteristics of the plants, but they don’t need to know the reason for the adaptations until after the activity, possibly during a class discussion.

Procedure

Divide the class into small groups of 2 to 3 students.
Hand out instruction sheets, clipboards, and pencils.
Tell students the specific length of time for the activity, where to regroup, and review the rules of conduct.
Have each group decide on who will be the recorder for the group as they check the appropriate boxes on the instruction sheets.
At the end of the activity, compile the data and talk about the plant adaptations to the dune environment.

Possible Extensions: Find a dune plant that is not one of the ten mentioned here and determine where it lives by its physical characteristics.