Lyman Dudley - June 2018

The summer field sampling season will really get underway for me in mid-June, as I head off with my team to our first extended (four week) sampling trip. However, in May, we took a shorter (five day) training trip to the Donkey Hills in Idaho. On this trip, we learned how to spot signs of pika occupancy in a talus patch, how to fill out a data sheet, and how to use our sampling equipment (GPS, range finder, finding aspect with a compass, etc…). The Donkey Hills were a good location to do training in because they are a small, low lying range in an arid area that does not have very high current occupancy, so we could get better at actually having to look for hay piles and urine stains on rocks, rather than just seeing pikas all over the place. Also, the snow had all melted off in the Donkey Hills by early May. To sample a talus patch, we typically start at the bottom of the patch and start hiking up it, looking for either pikas, white urine stains under large rocks or for hay piles (which are also usually under larger rocks). If we find a live pika or a green haypile, we mark the patch as currently occupied, and then mark a GPS point of where we saw the pika. Pikas usually stake out a home range that is about 25 meters wide, so we know that we won’t find another live pika within about 25 meters of the first one. If a live pika or green haypile is found, we will then look for and collect fresh pellets for our fecal stress analysis. Otherwise, if we only find old evidences of pikas in a patch, we mark the patch as extirpated (no longer occupied by pikas.) Either way, we mark down the GPS coordinates of any current or old evidences of pikas that we find and fill out a data sheet for the patch. The data sheet includes the names of all GPS points taken, the temperature and % cloud cover for that day, the type of evidence that was found, the slope of the patch and its aspect, the % of moss and lichen cover on the talus patch (a good predictor of aridity), and the names of all plants found within a 12 meter radius of the GPS point. Also, there is a checklist of factors that typically predict pika occupancy for a patch that we must mark yes or no for each patch we survey.

We have changed the mountain ranges that we will go to for this sampling trip to be the Lehmi Mountains in Idaho, and the Beaverhead and Tobacco Root Mountains in Montana. The reason for this change is that all of these mountain ranges run North to South, so we can document the rain shadow effect between patches on the west and east sides of these mountains. Our patches are all located on elevational transects that run up creek drainages so that we can examine the differing effects of elevation on pika occupancy and stress levels. As it turns out, the hardest part of sampling for me has been learning the names of every plant that I come across within a pika home range. I have had to carry around a rocky mountain plant guide and flip through it to compare pictures in it to the plants that I find. This has been the most time-consuming part of sampling so far, but I’m sure I will commit most of these plants to memory as the summer goes on. Also, marmots and wood rats leave very similar looking urine stains to pikas, which can be a source of confusion. To tell the difference you have to hike up to the urine stain, and see the leftover pellets or haypile that are likely to be nearby (pikas have different looking haypiles and pellets). So far I would say that I have gotten the hang of finding pika evidences and filling out data sheets, and it has been fun to get to know and explore new places with the other researchers on this project.

The team assembled in the Donkey Hills. In the background you can see the Lemhi Range, where we will be sampling in late June

A rock with a very obvious urine stain on it. Out in the field, you want to look for these white stains under larger rocks

Aimee taking it all in

Aimee and Kenny filling out field data sheets next to the site of a current pika occupancy


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