The California spotted owl (Strix occidentalis occidentalis) is a threatened subspecies of the endangered northern spotted owl (Strix occidentalis caurina). It occurs in southern California as a group of discrete populations within the San Bernardino Mountains of southern California. Their habitat is discontinuous in part because of human development activities. Individual populations have shown recent declines, which currently are attributed to increased isolation of habitat patches and natural environmental stochasticity. Dispersal between these populations is important for maintaining both the individual populations as well as the metapopulation.
Below is a list of the 23 populations in the model, some of which have abbreviations.
|
Number |
Full name | Abbreviated name |
| 1 | Northern Monterey: | N. Monterey |
| 2 | Southern Monterey: | S. Monterey |
| 3 | Cerro Alto: | C. Alta |
| 4 | Southern Santa Lucia: | S. Lucia |
| 5 | Sierra Madre: | S. Madre |
| 6 | San Rafael: | S. Rafael |
| 7 | Santa Ynez: | S. Ynez |
| 8 | Pinus: | Pinus |
| 9 | Tecuya: | Tecuya |
| 10 | Cobblestone: | Co. |
| 11 | Tehachapi: | Tehachapi |
| 12 | Pelona: | Pelona |
| 13 | San Gabriel: | S. Gabriel |
| 14 | San Bernardino: | S. Bernardino |
| 15 | San Jancinto: | S. Jancinto |
| 16 | Thomas: | Thomas |
| 17 | Santa Ana: | S. Ana |
| 18 | Palomar: | Palomar |
| 19 | Black: | B. |
| 20 | Volcan: | V. |
| 21 | Cuyamaca: | Cu. |
| 22 | Laguna: | Laguna |
| 23 | Sierra Nevada: | Sierra Nevada |
Use METAPOPW (S:\Courses\WLF448\RAMAS\) to explore the metapopulation and population dynamics of the California spotted owl using the cal-owl.mp model. See the in-class exercise for information on how to use the program. Please answer the following questions.
1. Run the model with the default values. Look at the Trajectory Summary and the Metapopulation Occupancy graphs for ALL populations combined. Also, view the numerical results. Based on these results, how many individuals and how many populations of California spotted owls will there be in 20 years? Hint: Outputs are average values (mean number per population or mean number of subpopulations occupied). Is there cause for concern? (4 points)
2. Use the tabular data (Display Mode = Numbers) to create a figure of metapopulation occupancy in Excel (or a software package of your choosing) in standard journal format. Your figure should look similar to the one generated by RAMAS. Show the mean, minimum, and maximum values, and include standard deviation bars (+1 SD). Be sure to label all axes and include a legend. Make sure your figure caption (below the figure) fully explains the data and allows the figure to stand alone. (7 points)
3. If juvenile survival to adulthood is increased to 50% (default was 30%), how many individuals and how many populations will persist after 20 years? (2 points)
4. What is different about the Sierra Nevada population, compared to all the other populations? (2 points)
5. Generally, which types of populations would be most influential to stabilize and why? Identify 2-3 subpopulations that seem to meet your criteria. NOTE: Make sure you answer the "why" portion of this question and that your reasoning is sound. (5 points)
Turn in the following (due next week at the beginning of lab):
Read directions carefully!
Answers to the 5 numbered items listed above (20 points). REMEMBER: answers must be typed and double-spaced. Points will be deducted for improper grammar, spelling errors, and poor organization. Make sure your name and lab-section number are on the front page. Please staple your pages in the upper-left corner.