Now we can vouch for the plants!

Early on in my dissertation work, I became interested in using a fairly new technique (DNA metabarcoding) to look at what our rodents are eating and if partitioning their diets might be one way so many species exist in our system. I’ll get into more of the details on that project in a subsequent post; for now, though, I want to tell you about a really fun ancillary project. When you’re interested in what the rodents are eating, it’s pretty important to know what they could be eating! Therefore, over the past few plant censuses, we’ve been collecting vouchers and DNA samples for as many of our plant species as we can find!

Having recorded plants at the site for roughly four decades, we are in a pretty fortunate position—we already have a nearly complete list of plants that could be found at the site. Since most of us know more about rodents than plants, however, we wanted to make sure we were correctly identifying our plant species. This requires collecting voucher specimens for every species we come across, pressing them in a plant press, and then dropping them off at the University of Arizona Herbarium for an official verdict from a botanist who specializes in Arizona plants. Once he has looked over our samples and identified them, the herbarium digitizes the specimens. So far, we’ve vouchered about 85% of the nearly 200 recorded plant species at the site.

Quadrats

Identifying plant species

Putting voucher specimens in the plant press

Delivering our precious plants!

Digitized copy of one of our vouchers

For the most part, we’ve been doing a pretty great job identifying our plant species, considering none of us really identify as botanists. We’ve also had some fun surprises along the way, though! For example, for forty years, we thought we had two species of Acacia at the site: 1) whitethorn acacia, Acacia constrica (now Vachellia constricta), and 2) catclaw acacia, Acacia greggii (now Senegalia greggii). As it turns out, however, we’ve probably never had the catclaw acacia at the site! What we’ve been calling A. greggii is actually a species of mimosa, Mimosa aculeaticarpa.

Senegalia greggii

This is not Acacia

This process has also made us more attentive to the plants surrounding us at the site. It was only at the last census that we noticed a large bush/small tree and realized that it was our first (and maybe only) desert willow tree, Chilopsis linearis, at the site. It was hard to believe we’d never noticed one of the biggest plants at the site as being different, but since it was just outside of a plot, there had never really been a reason to notice.

Example of a desert will tree, Chilopsis linearis

We’re looking forward to more surprises in the future, though we still dread having to figure out how to make these changes in the database!