Dr. Rebecca E. Drenovsky

One of my major research interests is plant nutrient resorption and storage, and I seek to understand how these physiological functions influence community and ecosystem processes (both nutrient limitation and soil nutrient cycling). Nutrient resorption and storage in perennial species conserves plant nutrient pools, decreasing plant reliance on current external nutrient supply and buffering the impact of annual variation in nutrient availability. At the whole-plant level, more complete nutrient resorption can increase plant fitness, a major driver of population dynamics. In contrast, complete resorption can negatively impact ecosystem-level processes. Since more complete resorption leads to nutrient-poor litter, decomposition processes are slowed, influencing site fertility and ultimately plant community composition. Despite the major role nutrient resorption and storage may play in population, community, and ecosystem level processes, there are significant gaps in our knowledge, such as: What is the relative importance of phylogeny versus environment on nutrient resorption? How do environmental factors influence realized resorption? Do other nutrient conservation or allocation mechanisms compensate in years of poor resorption? Using multi-year field sampling, manipulative studies, and meta-analysis of published works, my ultimate goal is to gain a better understanding of how environmental variation, storage, and recycling drives community and ecosystem processes. This research is highly relevant given current pressures on native environments. By understanding plant physiological responses to these changes, we can better predict feedbacks on community dynamics and ecosystem processes.

This work is in collaboration with researchers at UC Davis, the UC McLaughlin Reserve, the UC Sierra Foothills Research and Extension Center, and Dr. Tom Short as well as undergraduate and graduate students at JCU. Field research is being conducted in the California Coast Range, Great Basin Desert, and Mojave Desert.

Functional traits related to invasive species success

Exotic plant invasions pose a serious global ecological and conservation threat to native plant communities and can induce serious economic costs. Given their potential negative impacts, it is of interest to ecologists and invasion biologists to understand which traits makes some species more invasive than others. We know that some non-native species, following their arrival to a new area, simply naturalize and become part of the resident plant community. In contrast, other species experience rapid range expansion and are considered invasive. Determining which traits contribute most strongly to non-native organisms’ competitive ability is an essential first step in improving prediction and management of invasive species spread.

Previous research has focused on species diversity or functional group diversity as a mechanism of invasion resistance. However, coarse functional or taxonomic groupings may not capture traits enabling invasive plants to outperform native ones. Our research focuses on key morphological and physiological functional traits involved in resource acquisition and use, particularly in resource poor environments.

This research is being conducted in collaboration with researchers at the UC Sierra Foothills Research and Extension Center, the Exotic and Invasive Weeds Research Unit, and undergraduate and graduate researchers at John Carroll.

Mineral nutrition of plants growing on unique soil types

Unique soils, such as serpentine or gypsum, are hotspots of biological diversity. As such, they are excellent locations for asking questions related to adaptation and acclimation, as well as being areas of conservation concern. In addition to projects related to nutrient resorption and storage at the UC McLaughlin Reserve, the Drenovsky lab is investigating questions related to seed and seedling ecology of serpentine and non-serpentine shrubs, as well as plant-soil relations on gypsum outcrops in the Chihuahuan Desert. Our work seeks to understand the physiological mechanisms promoting adaptation to these unique soils and how they relate to species evolution in these habitats.

This work is being conducted in collaboration with researchers at the UC McLaughlin Reserve, Dr. Mike Moore of Oberlin College, and Dr. Sara Palacio of IPE-CSIC.