Tag Archives: lter

Southwest Regional Student Meetup – Grasslands, Deserts, and Cities

by Megan Wheeler, Brian Kim, and Alesia Hallmark

Last October at the LTER All Scientists’ Meeting in Monterey, California the graduate student committee identified between-site relationships as a key component of our mission statement. Building on the momentum from the October meeting, graduate students from the Sevilleta and Jornada Basin LTERs joined the CAP LTER in Scottsdale, Arizona for a regional meetup in conjunction with CAP’s annual All Scientists’ Meeting (ASM).

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CAP and Sevilleta students at South Mountain Preserve, with the city of Phoenix in the background.

The ASM started out with a captivating presentation by Marc Johnson from University of Toronto discussing urban evolution and the story of a ubiquitous weed, white clover. This unassuming plant is capable of cyanogenesis, the production of hydrogen cyanide, in response to herbivory. Work in Johnson’s lab has shown that the genetically-coded ability to perform cyanogenesis varies along an urban to rural gradient, and he unfolded the story of how temperature, region, and snow removal are related to the presence of responsible genes.

The plenary talk was followed by short presentations of different themes within CAP research, ranging from Governance & Institutions with a strong social focus to Water & Fluxes with a biogeochemical lens. Students, faculty, and staff then shared their research in two poster sessions, which started out with each presenter giving a brief 1 minute overview of their poster to the room. For the many first-time poster presenters, this was probably the most nerve-wracking moment of the day! During the poster session, some overlapping research interests between the two sites became apparent. Several Sevilleta students presented work on arid grass- and shrubland pollinators, while CAP students presented about the roles and perceptions of pollinators in the urban environment.

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SESE graduate student Marisol Juarez Rivera describes her poster, “Is oxygen supersaturation in Tempe Town Lake mainly driven by abiotic processes?”

Visiting students said the urban focus of the meeting was totally different that the ecology they were used to seeing presented. One student suggested that it made her think about how work at the Sevilleta could be expanded out to urban sites in Albuquerque, where most Sevilleta LTER students live.

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Students present posters at the CAP ASM. Presenters: top left – Tim Ohlert, top right – Aaron Grade, bottom left – Nich Weller, bottom right – Kate Weiss.
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Poster presentations.

The next day, CAP students led a tour to one of CAP’s long term experimental sites at an urban desert preserve. After hiking around and taking lots of photos, Sevilleta students found the vegetation of our Sonoran Desert sites wasn’t totally different from what was found on the Sevilleta grassland. Several genera and some species could be found in both sites. Despite the urban focus of CAP, the ecological context of Phoenix and the Sevilleta were not all that different.

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CAP and Sevilleta students explore Sonoran Desert vegetation while hiking at South Mountain Preserve, a CAP long-term research site.
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Wildflowers in bloom at South Mountain Preserve.

We enjoyed this opportunity to engage with other students across sites and learn a little more about where our research intersects and where there might be possibilities for collaboration. In the future, the Graduate Student Committee plans to support similar events at different groups of sites with the goal of continuing to build and strengthen graduate student connections within the LTER network.


Understanding species’ responses to climate change

by Cliff Bueno de Mesquita, Niwot Ridge LTER

This month Cliff will be sharing some of his dissertation work from his beloved alpine field site at the Niwot Ridge LTER site in the Colorado Rocky Mountains (Fig 1).

Figure 1. View of the Niwot Ridge LTER Site in the Rocky Mountains, Colorado, USA. Photo by William D. Bowman.

Mountainous areas often experience a greater magnitude of climate change than other areas. Data collected from our long-term records at Niwot Ridge show that summer temperatures are increasing (Figure 2) and snow is melting out earlier. How will plants respond to these changes?

Figure 2. Increasing summer temperature trends at Niwot Ridge. Shown are lines from linear regression (red) and a loess function (blue). From Bueno de Mesquita et al. 2018, Arctic, Antarctic, and Alpine Research.

One way plants and other organisms can adapt to climate change is by moving into suitable habitats. As climate warms, this typically means moving either up in elevation, or poleward in latitude. To colonize new areas, plants rely on their seeds to first disperse there, after which they must successfully germinate, grow, and survive. Such distributional shifts are important because if organisms can’t track their suitable climate for growth and reproduction, they could be killed either by unfavorable conditions where they currently are, or competition from more warm-loving species that are thriving in the warmer climates.

Here at the Niwot Ridge LTER, an experiment just concluded in which we hauled pots (Fig 3) of several alpine plant species up to 3900 m elevation (12800 ft) and transplanted them into unvegetated soils beyond their current range. We manipulated when the snow melted as well as which microbes the plants were grown with to see how these two factors influenced plant performance in a new habitat. By microbes, I mean the microscopic bacteria and fungi that grow in soil and often play important roles for plants, particularly in making nutrients plants need more available. To manipulate snowpack, we spread a thin layer of black sand onto the snow to absorb more solar radiation relative to clean snow. Think about what it’s like wearing a black shirt on a sunny day compared to a white one! To manipulate the microbes, we grew plants in soil collected from different areas that we knew had different microbes.

Figure 3. Our team of strong ecologists carrying up the transplants on a stretcher! Photo by Jane G. Smith.

After two years of growth at our site on Niwot Ridge, one of the three plants were doing very well, while the other two mostly died. The one plant that had good survival had differences in growth depending on which microbes we gave it, suggesting the microbes played a role in plant growth in new habitats. We also observed the snowbed melted out earlier and earlier each summer, such that by the 2nd summer, we saw negative effects of earlier snowmelt on plant survival. Areas where snow melted out too early may experience dry conditions later in the summer. Overall, our results show that 1) not all plants will be able to colonize new habitats to track suitable climates, 2) microbes can influence plant growth in new habitats, and 3) early snowmelt may help plants colonize higher elevation areas, but too early snowmelt may be detrimental, likely due to less water availability later in the summer.

Author Biography: Cliff Bueno de Mesquita is a doctoral candidate in Katie Suding’s lab in the Department of Ecology and Evolutionary Biology at the University of Colorado Boulder. Having first been a participant in the Research Experience for Undergraduates program at Niwot Ridge, then moving on to conduct all of the field work for his dissertation on Niwot Ridge, he has worked on Niwot Ridge for six summers and enjoyed every moment (except for maybe the scary thunder hailstorms)! Outside of the lab, Cliff enjoys spending time in the mountains hiking, climbing, and skiing, as well as playing rock n roll music with his band, The Casual Ales.