Introduction
Here at California State University, Northridge we see squirrels on a daily basis. Squirrels are usually a trailing thought in our head and we never really focus our attention on them, unless they try to run away with our food. We see them as mere pests, but squirrels are a unique group of mammals that provide many niches for our ecosystem.
This project is looking to help these interesting critters by looking for ways to close their habitat gaps.
These species are starting to become dependent on humans and if we set aside lands for them we can help keep them wild and operating how nature intended them to be.
Background
The squirrel species selected for this project are as follows:
Golden Mounted Ground Squirrel
Callospermophilus lateralis
Type of ground squirrel found in mountainous regions. Can be identified by its chipmunk like stripes and coloration but unlike chipmunks it does not have facial stripes.
About 23-30 cms long.
Douglas Squirrel
Tamiasciurus douglasii
Pine squirrel that inhabits pacific coastal states. Their appearance changes from season to season, but one significant quality is that they have a white eye ring.
About 33 cms long.
Northern Flying Squirrel
Glaucomys sabrinus
One of the only two species in the Genus Glaucomys. This species of squirrel is nocturnal. They can be identified by the patagium which is the skin that extends between their arms and legs granting them gliding abilities. they can also be identified by their long whiskers which are typical of nocturnal animals.
Range from 25-37 cms.
Western Gray Squirrel
Sciurus griseus
The western gray squirrel is a rodent found on the western coast of the USA and Canada. They are typically a shy species and run away from anything. They exhibit a coloration known as counter-shading which means there top is gunmetal grey in color and there underbellies are white. Their tails are also normally very bushy.
about 45-60 cms.
Round Tailed Ground Squirrel
Xerospermophilus tereticaudus
The round tailed ground squirrel lives in the deserts of Southwestern United States. They are called ground squirrels because they typically burrow in soil under trees and bushes. They are a sandy color and have a long round tail and long, hairy hind feet.
They typically range from 8 - 10 inch
Belding's Ground Squirrel
Urocitellus beldingi
This is a medium sized squirrel with short limbs, short tail, and small ears. They can be distinguished by the three color bands on their tail, one black, one white, and one red. It is mostly a cinnamon brown that turns to reddish brown on the underside.
They range from 23-30 cms.
Townsend's Ground Squirrel
Urocitellus townsendii
This squirrel is typically found in high desert shrublands in the United States. This species is listed as vunerable. These squirrels are more short and stocky, and they have a bushy tail. They also have bar like colorings on their back and tail.
they range from 14-18 cms.
White-Tailed Antelope Squirrel
Urocitellus townsendii
This squirrel highly resembles a chipmunk. It is a ground squirrel that is found in arid regions of the Southwestern United States. They can easily be differentiated by their white stripe that flows from the sides or their body all the way to the tail. This squirrel is also omnivorous.
Length 19-24 cms.
Rock Squirrel
Ostospermophilus variegatus
Moderately sized ground squirrel that is found in rocky areas. Although they are a ground squirrel they can easily climb trees just as well as tree squirrels. They are rather shy and difficult to observe from close range.
About 46.8 cms. long
California Ground Squirrel
Ostospermophilus beecheyi
This ground squirrel is one of the most common squirrels found in California. They are often cnsiered pests as they feed on ornamental plants in gardens. Some of these squirrels hibernate in the winter if there is heavy snow. They have also developed techniques to differ snakes from eating them.
About 30 cms long.
Callospermophilus lateralis
Type of ground squirrel found in mountainous regions. Can be identified by its chipmunk like stripes and coloration but unlike chipmunks it does not have facial stripes.
About 23-30 cms long.
Douglas SquirrelTamiasciurus douglasii
Pine squirrel that inhabits pacific coastal states. Their appearance changes from season to season, but one significant quality is that they have a white eye ring.
About 33 cms long.
Northern Flying Squirrel
Glaucomys sabrinusOne of the only two species in the Genus Glaucomys. This species of squirrel is nocturnal. They can be identified by the patagium which is the skin that extends between their arms and legs granting them gliding abilities. they can also be identified by their long whiskers which are typical of nocturnal animals.
Range from 25-37 cms.
Western Gray Squirrel
Sciurus griseusThe western gray squirrel is a rodent found on the western coast of the USA and Canada. They are typically a shy species and run away from anything. They exhibit a coloration known as counter-shading which means there top is gunmetal grey in color and there underbellies are white. Their tails are also normally very bushy.
about 45-60 cms.
Round Tailed Ground Squirrel
Xerospermophilus tereticaudusThe round tailed ground squirrel lives in the deserts of Southwestern United States. They are called ground squirrels because they typically burrow in soil under trees and bushes. They are a sandy color and have a long round tail and long, hairy hind feet.
They typically range from 8 - 10 inch
Belding's Ground Squirrel
Urocitellus beldingi
This is a medium sized squirrel with short limbs, short tail, and small ears. They can be distinguished by the three color bands on their tail, one black, one white, and one red. It is mostly a cinnamon brown that turns to reddish brown on the underside.
They range from 23-30 cms.
Townsend's Ground Squirrel
Urocitellus townsendii
This squirrel is typically found in high desert shrublands in the United States. This species is listed as vunerable. These squirrels are more short and stocky, and they have a bushy tail. They also have bar like colorings on their back and tail.
they range from 14-18 cms.
White-Tailed Antelope Squirrel
Urocitellus townsendii
This squirrel highly resembles a chipmunk. It is a ground squirrel that is found in arid regions of the Southwestern United States. They can easily be differentiated by their white stripe that flows from the sides or their body all the way to the tail. This squirrel is also omnivorous.
Length 19-24 cms.
Rock Squirrel
Ostospermophilus variegatus
Moderately sized ground squirrel that is found in rocky areas. Although they are a ground squirrel they can easily climb trees just as well as tree squirrels. They are rather shy and difficult to observe from close range. About 46.8 cms. long
California Ground Squirrel
Ostospermophilus beecheyi
This ground squirrel is one of the most common squirrels found in California. They are often cnsiered pests as they feed on ornamental plants in gardens. Some of these squirrels hibernate in the winter if there is heavy snow. They have also developed techniques to differ snakes from eating them.
About 30 cms long.
Interesting Exceptions
It is important to note that a few species of squirrels that live in California were not included for this project. These species are considered invasive species and we do not want to support their reproduction in our state as it will harm our native species.
The biggest example of these species is:
Eastern Fox Squirrel
Sciurus niger
These squirrels tend to be everywhere. Their color hue is shades of lighter brown with a reddish tint. Their tails are bushy and very long. They are a type of tree squirrel and thrive very well across the United States. These squirrels are not shy and display aggressive behavior when it comes to food. this is important as they are slowly dominating the native species range.
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These squirrels can typically be seen meandering through California State University, Northridge
Note the small contingency of them in Los Angeles County - That is Northridge
The biggest example of these species is:
Eastern Fox Squirrel
Sciurus niger
These squirrels tend to be everywhere. Their color hue is shades of lighter brown with a reddish tint. Their tails are bushy and very long. They are a type of tree squirrel and thrive very well across the United States. These squirrels are not shy and display aggressive behavior when it comes to food. this is important as they are slowly dominating the native species range.
.jpg)
These squirrels can typically be seen meandering through California State University, Northridge
Note the small contingency of them in Los Angeles County - That is Northridge
Study Site
The study site for this project is the entire state of California. This map illustrates what California looks like and points out a few features.
National Parks were added for reference as to what is already set aside.
National Parks were added for reference as to what is already set aside.
Data Gathered
Data was gathered from a few different websites. Many of these websites were government databases, but a few also include academic research sites. The majority of the data came from the California GAP Analysis project that was performed by UCSB. The final project UCSB completed can be viewed at the following link. http://www.biogeog.ucsb.edu/projects/gap/gap_home.html
Data for this project included:
Data for this project included:
Major Roads of California - "T- Drive"
Hydrology of California - "Cal-Atlas"
Land Management of California - "UCSB GAP Study"
Land Cover of California - "UCSB GAP Study"
Squirrel Habitat Ranges - "Department of Fish and Game, California"
Major Cities of California -
Counties of California - "TIGERline Census Data"
Next we will organize the data gathered in order to be effecient in the planning of this project.
An E-R Diagram will be drawn to help organize this data
E-R Diagram
This diagram organizes the information that was gathered andnow to be stored in the geodatabase. The main file in particular is California and all resulting shapefiles or entities fall within the California context. In Geographic Information Science it is a good methodology to organize the data you will gather before you begin to create your geodatabase, by doing so you allow for less areas during the geodatabase creation.
The diagram is read in a top to bottom, left to right format.
The cardinality rule demonstrates the relationship between entities. For example 1 California contains Many counties. It also works in reverse, Many counties are within 1 California.
Squirrel Genus and Species was added to give an idea of what specific examples will be used for this project.
The next post will show what the the same information but listed in the master entity list
Master Entity List
The Entity List is basically the information from the E-R Diagram but in list form for the data. The entity list does not display the relationship between the entities. This is mostly made for reference but does provide valuable insight into the organization process.
Geodatabase Design Forms
Some of the feature classes of the feature dataset have been listed to show the quantities of the data.
This next worksheet shows what some of the attribute tables of each feature class will contain. Keep in mind that an attribute holds a great deal more information, but this is a basic outline for reference. The null field determines whether a value can or cannot exist for a particular attribute. If null is checked to Y(yes) that means data is allowed to not exist in this category. The domain category states that an attribute may have a set of values allowed for that category. These are also known as domains.
Prelimanary Analysis
After all the data was gathered and organized, preliminary analysis could begin.
First current squirrel ranges were looked at to see trends in ranges.
These maps display the ranges of these squirrels and how they relate to California
We can see a few spatial trends between the squirrels. A highly populated area of squirrels is the Sierra Nevada mountain ranges, as well as the Southern Desert.
First current squirrel ranges were looked at to see trends in ranges.
These maps display the ranges of these squirrels and how they relate to California
We can see a few spatial trends between the squirrels. A highly populated area of squirrels is the Sierra Nevada mountain ranges, as well as the Southern Desert.
Method
In performing the GAP analysis, the first step is to join the Vert file to the landcover file. The Vert file contains a suitbaility analysis for each species in california. The selected squirrel species were taken from this file provided by UCSB. The suitability data gives a range from 1 to 5 for each landcover region of California. 1 is the least suitable, whereas 5 is the most suitable.
All of the polygons that achieved 5 for each species were queried and then exported to create new range layers that demonstrated the most suitable areas for squirrels.
These maps demonstrate that selection
We can see a spatial difference between species of squirrels living in the southern inland portion of California, and the Northern Coastal-Sierra species. This brings us to the conclusion that this process will affected by this spatial distribution. In dividing the species up based on location the ratio of squirrels was 7 species to 3.
These 7 species will now be qualified for the GAP analysis. These species include: Golden Mounted Ground Squirrel, Douglas" Squirrel, Northern Flying Squirrel, Western Gray Squirrel, California Ground Squirrel, Belding's Ground Squirrel, and Townsend's Ground Squirrel.
The next map illustrates the tool
All of the polygons that achieved 5 for each species were queried and then exported to create new range layers that demonstrated the most suitable areas for squirrels.
These maps demonstrate that selection
We can see a spatial difference between species of squirrels living in the southern inland portion of California, and the Northern Coastal-Sierra species. This brings us to the conclusion that this process will affected by this spatial distribution. In dividing the species up based on location the ratio of squirrels was 7 species to 3.
These 7 species will now be qualified for the GAP analysis. These species include: Golden Mounted Ground Squirrel, Douglas" Squirrel, Northern Flying Squirrel, Western Gray Squirrel, California Ground Squirrel, Belding's Ground Squirrel, and Townsend's Ground Squirrel.
The next map illustrates the tool
Aknowledgments
I would like to thank all of the people who have helped inspired this project
To the squirrels and their nation for giving me a topic
To the rest of my 406 class for giving me input and advice
To Sabrina Esquivel for all the help with GAP Analysis
Hope you all enjoyed A SQUIRREL HOPE
and
Coming soon to a project near you: THE FOX SQUIRREL STRIKES BACK
and
Even later: THE RETURN OF THE CHIPMUNKS
and
Even later: THE RETURN OF THE CHIPMUNKS
Rolling Credits
With the destruction of the DEATH BURROW.
The EASTERN FOX Squirrels plan their retaliation
The EASTERN FOX Squirrels plan their retaliation
Were coming for you
Darth Squirrelius - The Eastern Fox Squirrel
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