Sevilleta Long Term Ecological Research

The Sevilleta Long-Term Ecological Research (LTER) program is a Long-Term Ecological Research program in New Mexico that expands our understanding of the biological processes in drylands.  Litvak has been a Co-I on the Sevilleta LTER since 2006. We are addressing big questions in ecology, centered on environmental variability. The fluctuating nature of drylands makes them excellent study systems to improve general understanding of the biological consequences of environmental variability.  The five primary questions addressed in our conceptual framework are:

1. How do climate variance and long-run mean drive biome transitions?
2. Why are some biomes and ecotones more sensitive to climate mean and variance than others?
3. How will changes in climate variance and mean affect biome-specific biogeochemical processes and alter biophysical feedbacks?
4. How do climate-driven changes in resource landscapes affect consumer dynamics?
5. How do disturbances alter climate sensitivity or antecedent effects?​

Five of the flux towers in the New Mexico Elevation gradient are in the five focal biomes of the Sevilleta LTER and help address questions related to drivers/consequences of biome transitions, and add to the long term monitoring of ecosystem processes in these biomes.   

More info on flux towers at the Sevilleta LTER
Video on flux towers at the Sevilleta LTER
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Quantifying the effects of species range shifts and management of post-

fire recovery on regional carbon dynamics in a changing climate

Funding:    USDA NIFA, Interagency Carbon Cycle Science

Research Team:  Matt Hurteau (PI), Dan Krofcheck (UNM), Marcy Litvak, Scott Collins (UNM)

Objective: Semi-arid ecosystems play a dominant role in governing the trend and interannual variability of the land carbon (C) sink at global scales and source-sink dynamics in these biomes are a function of interannual climatic variability and disturbance. In the southwestern US, regional climate models project warmer temperatures, decreased winter precipitation, and more variable summer rainfall regimes, patterns that are already evident in the recent past. As a consequence, widespread conifer mortality is projected for this region, driven by increasing aridity and severe, climate change type droughts. Widespread conifer mortality has the potential to substantially alter C cycle dynamics and terrestrial C cycle feedbacks to the atmosphere. While widespread conifer mortality is projected for the future, larger, hotter wildfires are already driving vegetation changes in many semi-arid systems.  Coupled with changing climate, wildfires could serve to catalyze shifts in vegetation types towards ecosystem compositions with a lower carbon state. The overarching goal of our proposed research is to understand how potential changes in species range distributions and post-fire establishment success will affect regional carbon dynamics in the southwestern US under future climate change scenarios.

This research answers three primary questions:

1. How do topography and fire severity interact to affect the spatial arrangement of vegetation across the landscape, and what implications does that have for changes in surface radiation energy balance and water availability for seedlings?
2. Given 1, where on the landscape is seedling survival most probable and how does species selection for reforestation efforts alter survival probability?
3. How do post-fire reforestation efforts using climate-adapted species alter future carbon dynamics across the landscape?