Map of all 10 sites at Ravenna Park
Welcome to Ravenna Park! Imagine
I am taking you on a walking tour, showing you 10 specific sites. Each site
will discuss a specific topic relating to natural history. I hope you are able
to learn something new about this unique park in the middle of Seattle. Enjoy!
Site 1: Ecological Disturbance
As I began my final trek to Ravenna Park, I put on my rain boots for the last time. For the last quarter, I have been monitoring one specific site at Ravenna Park. The route to get to my location is not a conventional one. You must walk through mud and crossed a nurse log to make it to the location. Once at my location, I stand beside a Western Red Cedar. This is the closest I can get to the creek without having rain boots sink into the mud about 10 centimeters.
Over the 11 week quarter, I have tracked the ecology of Ravenna Park has changed
throughout the fall season. It is important to look at how the ecology looked
at the beginning of the quarter, to help compare to what it looks like now. When
I first visited the site all the plants were green including plants like the Western Sword Fern and the Giant Horsetail. My observation
location, a small branch was growing out of the Western Red Cedar directly
behind me. It seemed unimportant, at the time, so I did not consider it to be
something worth noting.
Dried out Western Sword Fern beside the creek.
Branch of the Western Red cedar has grown significantly
More than half the trees in
the forest had lost their leaves. These trees I had previously identified
as Red Alder and Big Leaf Maple. Each of these
tree types is deciduous, meaning they loose their leaves annually. No leaves on
trees, allows you to see up to 15 meters in all directions. This change in
visibility is important to animal life. Birds that hid in deciduous trees
during the summer now have to find other ways to remain hidden. Additionally, the
change in seasons makes it difficult for these animals to find sufficient food.
A good example of this is the understory of the forest. In the summer, plants
like Salmonberry thrive. The berries from the salmonberry
are an important meal to the animal life in the area.
Final picture of my blog location with the Western Sword Fern beside the creek.
Final panoramic of my blog site
Ecological changes shown throughout the quarter.
Site 2: Human/Ecological Disturbance
From my Ravenna Park site, I continued down the trail to find another location to stop at. I stumbled upon an area that had few trees. The understory was sparse, with few plants like ivy growing along the floor. From where I stood, there were trees about 10 meters away from me in all directions. I knew immediately, this was not how the forest should be set up. Something or someone had tampered with the area.
Panoramic of site 2 at Ravenna Creek.
After thinking more about
this, it became clear that there was both humans and ecological disturbance in the
area. An ecological disturbance is when specific event or events have changed
caused mass plant mortality and has overall changed the structure of the
environment. How was Ravenna Creek disturbed? First off, there were fallen logs
in the river, causing the flow to slow down. The logs have allowed for the
creation of a pond like area in between fast flowing creek on either side. This
is an ecological disturbance because the logs fell naturally but still caused a
slight disturbance in the flow of the creek. In addition to ecological
disturbances, there are clear human disturbances as well. In this specific
location, the cutting of trees has greatly affected the area. Before, a
thriving tree was growing in the creek, creating shade for understory to grow.
Now, the stump has been left in the water, not allowing plant life to grow
around it. The roots of the previous tree are still in the water, but unlike a
nurse log or snag, the environment is not able to benefit from the decaying
tree.
Pond like area that is formed from ecological and human disturbance.
Site 3: Land Use
To best explain land-use history, I wanted to find an area on one of the hills in the park. After a bit of walking, including an uphill climb, I found the spot. The location I choose was in between many trees on a steep incline. To understand the history of land-use, it is first necessary to know some history about Ravenna Park and why it is important. The park itself was created in 1887 by George and Oltilde Dorffel. As time went on, the park quickly became an important part of the city. (Blecha) People were able to enjoy nature in the middle of the city. As the University District and Ravenna grew, the public park was created. Today, people use Ravenna Park to enjoy a nice stroll, or even go for a quick run.
As the
city has grown, residential areas have surround Ravenna Park. This has caused
major pollution to the environment of the park. This pollution comes largely
from water run-off. When it rains, water moves through city streets and becomes
polluted with chemicals. Ravenna Park is a lower elevation from the city, so
the run-off goes down the hills into the creek. When the water is polluted, it
affects the entire ecosystem. Sensitive species are unable to develop and the
only species that survive are the ones that can withstand the toxins. The
run-off does not allow the park to reach its full potential.
The uphill view of site 3.
Additionally
to the water run-off, the park is open to the public. Although many people are
concise of keeping the park clean, there are some who still pollute. More than
once I have found people leaving bottles from drinks, sunglasses, and various
metal objects. These people abuse the privilege of having such a nice park in
the middle of the city.
Work Cited:
Blecha,
Peter."Ravenna Park (Seattle)." History Link. 23 Jan.
2011. Web. 1 Dec. 2014.
Site 4: Lichen/Fungi
At the fourth location, you can find many types of lichen and moss. In general moss and lichen tend to grow on logs, bare branches, and even leaves. The specific location I choose looks more at lichen instead of fungi, but I will mention some fungi that can be found in the area. One of the more common types of mushrooms is the mycena. It tends to be gilled, white with a brown top, and small. Also, a type of fungi I have seen in the past at Ravenna Park called the Turkey Tail mushroom. It is versicolored, or has multiple colors, and grows on the sides of wood branches.
The types of lichen I
found at the location include Usnea
Lichen, Hammered Shield lichen,
and the type of lichen found on western red cedar leaves. Usnea Lichen grows on bare branches and shrubs. It was unclear as
to what type of shrub the plant was growing on, but it is the end of fall so
all the conditions were right for its formation. Another place where you can
commonly find lichen is on western red cedar leaves. The leaves of the western
red cedar are flat and scaly, which help allow for lichen to grow easily. The
last type of lichen that can be found at this location is the hammered shield lichen. It grows on
nurse logs or bare branches. This specific type of lichen is tolerant to
pollution and is widespread. It grows on deciduous and coniferous trees.
Hammered Lichen has a upper surfaces that is smooth and a lower surface that is
black.
A close up shot of Usnea Lichen.
Lichen growing on the Western Red Cedar leaves.
Hammered Lichen growing on a bare branch.
Site 5: Plants
I continued to explore Ravenna. Without having a specific route in mind, I followed a trail that went to an area I had never seen before. A wooden bridge that appeared to connect to a residential area was to my right. Without realizing it, I had ended up at a spot that contained many of the plants we had learned in class.
The trees in the area were
easy to identify. A young Western Red Cedar grew about 5
meters from the creek. The needles of the western red cedar have what feels
like scales. Additionally, the red cedar is a conifer so it does not loose its
leaves due to the seasons. Another tree that appeared to be 20 meters tall was
a Douglas fir. Although I could not look at the needles, I identified
the try by its bark. The bark of the douglas fir is thick and grayish brown.
A young Western Red Cedar tree growing by the creek.
As I looked around, I saw
one type of Oregon grape covering much of the understory. Oregon grape is a
shrub that can be found throughout Ravenna Park. There are two different types
of Oregon Grape: Tall Oregon Grape and Dull Oregon Grape. Tall Oregon
Grape has glossy leaves tiny spikes coming out from the sides. There
are 7-9 leaves per branch and each leaf goes in different directions. Dull
Oregon Grape has dull leaves that lay flat. The Oregon grape that can
be found at this location was Dull
Oregon Grape.
A close up of Dull Oregon Grape.
Another part of the
understory was the Western Sword fern. The plant has fronds
that grow up to 80 centimeters. Each frond has little notches, or what you
consider little swords.
Picture of a Western Sword Fern that can be found at site 5.
Lastly, I found a Salmonberry growing
underneath the Dull Oregon Grape. The salmonberry grows close to the water has
a distinct leaf pattern. Generally there is a large leaflet with two smaller
leaflets growing perpendicular to it. Although there is no evidence of berries
on the salmonberry during the fall, in the spring it grows yellow orange
berries.
A close-up of a Salmonberry plant.
Although not a plant, I
wanted to mention that I found the Bulbous Bonnet Mycena at the
site as well. Mycena is a type of mushroom that has white gills and a white
bell-shaped structure. They can be found growing on leaves of deciduous and
coniferous trees.
Mycena growing in between coniferous and deciduous leaves.
Site 6: Animal Behavior
Throughout my many times of
going to Ravenna Park, I have slowly picked up some things about the animal
behavior around the park. To start, the weather outside has major effects on
how animals act. When it is pouring rain, many birds and ground animals like
squirrels find a dry spot. There are never any birdcalls to one and other when
it is pouring. Animals avoid the rain when they can. Alternatively, when there
is sun outside, the animals are out. I have seen far more squirrels running
around Ravenna Park on a sunny day. If you just sit and listen, you can hear
the birds chirping in the trees. The overall feel for Ravenna Park changes when
there is sun.
Mima Mounds Ravenna Park
Another thing that I have
noticed about the animals around Ravenna Park is how animal behavior depends
greatly on the landscape. When there are trees animals can more easily roam an
area. There are places to easily hide from predators. In the spring, it is
nearly impossible to find anything through the dense canopy and understory.
Therefore animals feel more at ease to roam around. In areas like Mima Mounds,
for example, it is harder to notice animals. This is because in the prairie
setting, it is necessary to hide from predators because visibility is higher.
Site 7: Interaction between species
Western Sword fern resting its fronds on fallen logs.
After considering more
than one type of interaction between species, for site number 7, I believe the
most is the connection between the western sword fern and nurse logs. Multiple
times, I have walked through Ravenna Park and noticed that western sword ferns
seem to grow in between large fallen trees. I have even seen the ferns growning
partially on a nurse log. Although this
may seem like a strange interaction between species, it makes a lot of sense; the
support from the nurse log, allows for the fronds to receive sunlight. For any
plant to survive it needs to photosynthesize, therefore a nurse log allows the
western sword fern to extend its fronds. The fern itself does not have to put
as much of its energy in making sure the fronds stand up to receive light. This
extra energy that is saved by the plant can help it survive in the colder
months.
Another more obvious
interaction between species is moss growing on the branches beside me. Moss
grows in densely matted with loose green tufts going in every direction. These
types of mosses tend to grow on the moist areas, especially on wetter side of
trees. To find out how polluted an area is you can also look at the types of
moss and lichen that grow in an area. Some moss types are sensitive to
pollution.
Site 8: Invertebrates
It is important to study invertebrates because they allow us to understand the health of water in specific areas. The best way to measure this is to look at evidence of disturbance. Some invertebrates are sensitive species that may only form in clean water. Sensitive species are a great indicator of disturbance because they only occur in specialized climates. Additionally, look at the % dominance of the most common taxa and long-lived taxa. These indicators help to find B-IBI index, which is a reference point to whether a ecosystem is healthy. If the percent is small compared to the taxa as a whole, you know that the river is polluted. This also allows for easy comparison of the pollution in different areas. Ravenna Park could be compared to other parks in Seattle by its % dominance. Specifically at Ravenna Park, the % dominance is rather low because of large amounts of pollutants in the creek. This means that it is unlikely to find sensitive species, like caddis fly larvae, which only forms in clean and clear water.
Picture of Site 8 with red arrows showing slow moving water areas.
When taking this concept and applying it to my location, it
is important to consider what types of invertebrates will form by the creek.
Pollution tolerant species like the pill bug and slugs will
form. Other common invertebrates that can
be found at Ravenna Park are millipedes and small spiders. In addition to pollution, the
areas invertebrates form is dependent on the speed of water a specific points.
Larvae needs slow water movement to form. These results were found one of my
other classes in the Ravenna Park creek. If you look at the picture, there are
red arrows pointing to the areas where you are more likely to find invertebrate
larvae.
Site 9: Birds
Gesture Sketch of the Bewick's Wren I saw at Ravenna Park.
There are many birds that prominent in the Pacific northwest including, the song sparrow, bewick’s wren, and barred owl. The song sparrow is a brown and gray bird that can be found in shrubby areas. Generally it is found in low, open, and wet areas. This type of sparrow has a short bill and stout, which is unlike other sparrow species. The next type of bird that can be found is the bewick’s wren. At my blog site for the quarter, I tracked a bewick’s wren in the bushes. It is a hyperactive bird that tends to jump from branch to branch, quickly. It has a slender body with a long bill. Earlier in the quarter, I found the wren in some bushes. I miss identified it as a song sparrow and played the call. Quickly the wren responded by flying away towards the creek away from me. Song Sparrows and Bewick’s Wrens are direct competitors for food. The two birds actually look very similar at first glance. It is best to listen to their calls to identify them more easily. The last type of bird, which is more rare, is the barred owl. The barred owl is a large brown and white owl with a round head. Owls are not easy to find because of their feather formation. The feathers allow for air to dissipate at a different frequency that humans and animals can hear, making it easy to pounce on prey. I have not seen a barred owl at Ravenna Park, but I have heard its distinctive call. When it hoots it sounds like “who cooks for you? Who cooks for you-all?” One day when I was walking around Ravenna, I heard this call and immediately knew a barred owl was near.
Site 10: Geomorphology
I decided on making my final location the erratic at Ravenna Park. To understand the geology and geomorphology of Ravenna Park, it is necessary to look at the natural history of the site. About 16,000 years ago, a lake, known as Lake Russell, that covered the western half of Canada and most of Washington. The world was going through an ice age and 14,000 years ago this lake turned into the Cordilleran Ice Cap. The ice extended out the Puget Sound Area, called the Puget Lobe. A thousand years later, the glacier created a glacial lake. While this lake was formed, erratics were created. An erratic is a rock that gets left from glaciers and is unlike the rocks in the area. They tend to be randomly scattered across the landscape. The erratic at the park is glacial deposit from the previous ice cap in Washington.
A Panoramic Picture which is intended to show the randomness of the erratic at Ravenna Park.
While at this site, it is
important to discuss the geology of Ravenna Park itself. Ravenna Park was
formed by ice that melted off the Vashon Glacial Ice sheet that later formed
Lake Russell. As time went on, Lake Russell disappeared but there was still
direct drainage from Green Lake. Ravenna Creek was the Green connection to Lake
Washington. (“Ravenna Park”) The water was diverted from the lake, leaving
Ravenna Park with a direct flow of water. Much of the water now in Ravenna Park
is run-off from the city.
Close up of the erratic.
Work Cited:
"Ravenna
Park." Seattle.gov Home. Seattle.gov. Web. 1 Dec. 2014.
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