American Pikas and Climate Change: Occupancy and Temperature along an Elevational Gradient in the Eastern Cascade Range

Student: Bridget Smith

Mentor: Kristina Ernest

Abstract

American Pikas (Ochotona princeps) have a narrow range of temperature tolerance and are a climate-sensitive species. The primary goal of this project was to investigate whether environmental temperatures are associated with pika presence at rocky habitat sites along two elevational gradients on the eastern slope of the Cascade Range in Kittitas Co., Washington. We selected three sites along the Palouse to Cascades State Park Trail and four in Manastash Canyon. Paired data loggers at each site recorded surface and subsurface (60 cm deep) temperatures every 15 minutes from late summer through early fall. We conducted pika occupancy (presence) surveys during October 2019. Surveys included focal (visual and auditory) and walking observations (search for haypiles and latrines). Generalized linear models (GLM) were used to model the probability of pika presence as a function of various derived temperature measures. Over the duration of the study, subsurface temperatures at all sites did not rise above 25.5°C, pikas’ critical upper temperature. GLMs suggested that both surface-level mean maximum temperature and number of hours above 25.5°C reasonably predicted pika occupancy. Contrary to our expectations, sites with higher temperatures were more likely to be occupied than sites with lower values for both models. Other studies suggest that snowpack and winter temperatures may be more important determinants of pika presence than are summer temperatures. Our small sample size prohibits generalization about summer temperatures, but the results suggest that further research is needed to explore the impacts of temperature on pika occupancy at low-elevation sites.

Presentation

12 thoughts on “American Pikas and Climate Change: Occupancy and Temperature along an Elevational Gradient in the Eastern Cascade Range”

  1. Hi Bridget,
    Neat study! Given your data, do you think this makes it more or less likely that pikas can successfully navigate climate change?

    1. Thank you! Unfortunately, my sample size is not large enough to say pikas are more or less likely to successfully navigate climate change even for the small area surveyed. There was a study published earlier this year that looked at pika activity at low elevation and at high elevation sites and they found that pikas at the lower elevation sites exhibited more crepuscular activity than their higher-elevation counterparts. Given the results from that study, I’d say it gives some hope that pikas can adjust their behavior to help them survive climate change to some extent. However, they exist in metapopulations and do not disburse well, so the outlook is still not very bright.

  2. Great presentation this seems like a fun experiment to do where you are able to go out in the field. Pikas seem to like warmer temperatures to live in, I was wondering if in your background research you came across any information about how they deal with colder climates such as in winter time?

    1. Given the data I collected, it might seem like they do. However, my sample size was quite small (7; 3 from the Palouse to Cascades State Park Trail, and 4 from Manastash Canyon). The results are interesting, though because it’s the opposite from what we would expect given their temperature sensitivity. Previous research has found that sites with higher temperatures were more likely to be abandoned by pikas that sites with lower temperatures.

      There has been less research done on winter conditions. While pikas are more tolerant of cold temperatures, snowpack amount and duration have been shown to be important during the winter months. Snowpack insulates pikas against the extreme cold.

  3. Hi Bridget,
    Very good presentation! If the temperature were to reach the Picas critical point in the future what do you think is most likely to happen. Will the Picas increase the elevation of their habitats so they are living within a lower temperature or will they be forced to push their habitats north?

    1. Pikas do not disburse well and usually stay in their home range once it is established, so I don’t think their range will necessarily move north, especially when there are a lot of anthropogenic obstacles. Over generations, I’d expect to see the range at which pikas live to move upward, especially for mid-elevation pikas. However, if pikas can persist at lower elevations where they do not have to deal with winter extremes, can take thermal refuge in the talus habitat, and have food available, will the low elevation pikas’ range move upslope?

  4. Hi Bridget,
    Interesting study, I was not expecting sites at higher temperatures would be more occupied than cooler sites. I think this research will be important to see if this population of picas will move up in elevation if temperatures continue to increase with climate change. Looking into winter temperatures should be interesting and hopefully give more insight into this population of picas. Nice job!

  5. Hi Bridget,
    I really enjoyed your presentation! I’ll admit I didn’t know much about Pikas prior to your display. I found your results very interesting and meaningful, thank you for all the graphs and breakdowns of the data, those visuals were very helpful as I listened. I wonder what this will mean for Pikas that aren’t as geologically close to an increased elevation, what do you think might happen to Pikas that are fairly far away from the cascades? Would they inevitably find higher elevation or somehow adapt?
    Thank you for this presentation, I learned a lot!

  6. Hey Bridget,
    Awesome presentation! Do you have any hypotheses on why the Pikas were found more often in higher temperarures than in low?

  7. Hi Bridget,
    I really liked your presentation. I found your results really interesting. If you were to continue this study, do you think you would try to take measurements in different seasons? I know you mentioned in the presentation that you had thoughts about how the results would change in winter conditions.

  8. Hey Bridget,
    this was a really well done presentation with a lot of good work. the graphs where great and told me a lot about the data. with global warming temperatures rising do you think that pikas will go to lower temperature areas so they can keep below there critical temperature

  9. This was a interesting study on the Pikas. My question for you is if you had another chance to do this study over again would you and how would you change anything? Nice job!

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