Research

Lethal Drought Index (current)

High levels of abiotic stress and competition are huge barriers to establishment of native species in CA grassland. With limited funding and resources, most restoration practitioners across the state are forced to consistently rely on the same seven “high-success” perennial species, representing a small proportion of possible functional and species diversity. In this study, we set out to characterize 17 native species’ responses to water stress using a novel Lethal Drought Index (LDI). We are conducting a greenhouse drought experiment to assess and compare physiological drought survival for 17 previously-uncharacterized native species alongside 5 of the “high success” species most frequently used in grassland restoration. We are imposing a lethal drought treatment to quantify lethal drought index (LD50), the intensity of drought associated with 50% population mortality (sensu Barkaoui and Volaire 2023). Using multivariate and linear statistical approaches, we are assessing how LD50 is associated with plant functional traits and other physiological thresholds linked to drought tolerance: leaf turgor loss point (πtlp), meristematic water content (LMWC), specific leaf area (SLA), leaf dry matter content (LDMC), and leaf nitrogen content (LNC). Our findings, alongside field-based measurements of these same traits at three coastal grassland restoration sites across the state, will be used to develop a trait-based restoration toolbox to inform species selection and optimize drought resilient restoration.

Big bluestem phenology in prairie restored with heterogeneity (2021 - 2023)

We leveraged a tallgrass prairie restoration experiment that has manipulated soil nitrogen availability and soil depth over 20 years to test the effects of environmental heterogeneity, nutrient enrichment, and two global change drivers (nutrient enrichment and a drought manipulation) on the phenology of a highly dominant prairie grass (Andropogon gerardii). 

You can read about our results in our Ecosphere paper, Nitrogen enrichment drives accelerative effect of soil heterogeneity on the flowering phenology of a dominant grass.

Morphology of Anolis distichus along an elevational cline (2019 - 2021)

We studied morphological variation in a population of Anolis distichus inhabiting a range of elevations across the Cordillera Central in the Dominican Republic. We evaluated the fit of Allen's Rule and Bergmann's Rule to variation in snout-vent length (SNL) and limb lengths in this population.