exercises

Field Trip: Point Reyes National Seashore, California

Pictures from 1997 field trip.

some questions to think about and answer ( if you can)

Note: The purpose of this trip is to examine several plant communities that occur in Northern California. Part of Biogeography is identifying plants and communities and understanding what, why and where they are.

1. Redwood Forest: Samuel P. Taylor State Park

Here the redwood (Sequoia sempervirens) forest is fairly well represented along the stream bottom. Many of the redwoods in this park occur in clusters, a result of vegetative sprouting from the trunk following lumbering in the 1850s. Note the thick litter under the redwood trees, the deep shade cast by these trees, and evidence of fire on the trunks -- all factors that serve to make this tree such an effective dominant species where conditions are right.

Can you locate any redwood seedlings? Where are they found? Why?

Note that many redwoods occur in circles here. How do you explain this? Do you see any evidence that fire has occurred in this forest?

Look at the trunks of the large conifers a few feet up the slopes. What are these trees? Their presence reflects the fact that proper moisture conditions for Coast Redwood are limited to the stream bottom.

2. Bishop Pine Forest: Mt. Vision Road

Here is your first walk through Bishop pine (Pinus muricata) forest. Some of the sclerophyllous shrubs present here include huckleberry (Vaccinium ovatum), salal (Glautheria shallon) and California lilac (Ceanothus sp.) .

At the first stop, notice the ground cover of the forest.

Is the canopy open?

What can you notice about the stand of Bishop pinesyou are looking at? Do they seem to vary in size, height and age?

Do you see any seedlings? If yes, where are they located?

What can you say about the community you're standing in?

Can you predict the future of this stand?

3. Coastal Scrub: Mt Vision Road

Across the road we'll stop in the coastal scrub community. Coyote bush is the most dominant species in this community.

Can you estimate its cover in this area? What other species do you see?

4. The Fire: Inverness Ridge

We'll travel a little farther on the road till it ends, park in the parking area and walk down into the region effected by the fire.

Let's examine the consequences of the October 1995 fire.

What burned, what didn't? What's coming back? What is absent?

Look for signs of stump sprouting on the shrubs and seedlings of bishop pine.

How did the ferns fair in the fire, are they recovering?

5. Coastal Prairie and Rangeland: Chimney Rock

This area is reflective of the coastal prairie and coastal rangeland. It is known for the tremendous display of wildflowers in March and April. The substrate is typically rich and high in clay and organic matter.

As we start to walk along the trail notice the stand of Cypress to your right.

What can you say about the distribution of trees in this stand?

Where are all the trees and shrubs?

How many different flowering plants can you identify?

Can you determine the pattern of vegetation for any of the species?

What observations can you make regarding the Douglas Iris?

What is your assessment of the diversity of this community?

6. Coastal Beach and Dune/ Coastal Strand: North Beach

This is the Coastal Beach and Dune (Coastal Strand) Community.
On the foredunes: Introduced ice plants from South Africa are most conspicuous,
the native Mesembryantheum is much less common here and can be recognized by its small magenta flowers and shorter leaves. European beach grass (Ammophila arenaria) has also been planted to stabilize the dunes. You may also see beach sagebrush, silver beechweed, sand verbena, beach morning glory and introduced sea rocket.

Are these species randomly distributed, or do they tend to occur in specific microhabitats?

Note the prostrate coyote bush (Baccharis pilularis var. pilularis) that serves as "nurses" for various annuals like miners lettuce. Note also the blowouts in the dunes.

What evidence suggests that these areas were once vegetated?

What species seem to be the most successful in colonizing these blowouts?

7. Coastal Strand: Inland from North Beach

As we travel away from the dunes we see more plants have started to colonize these areas. Why?

How do these coastal dune areas compare with the coastal prairie at Chimney Rock?

Compare: Coastal Prairie and Coastal Beach and Dune

substrate

soil nutrients

plant cover

species diversity

vegetation reproduction

herbivore pressure.