Functional traits allow ecologists to develop mechanistic models that predict how ecological communities will respond to perturbations and how species will affect community and ecosystem processes in a rapidly changing world. Our research explores how plant biochemical and physiological traits drive ecological processes such as invasion, community assembly, and nutrient cycling. Click on 'Research’ to read more about specific projects.
Read about our current NSF-funded climate-change project here, or watch this video.
How do plants respond to reduced water availability?
Precipitation in arid and semi-arid environments can vary strongly within and across years and plant fitness can depend on rapid or efficient utilization of water during these events. Plant species adapted to arid systems possess numerous leaf, stem and root traits that serve to minimize water stress, but it remains unclear whether these water conservation traits limit a plant’s ability to rapidly respond to precipitation events. Our research addresses how traits pertaining to water acquisition and conservation correlate with plant fitness in plant species from a southern California coastal sage scrub community.
What factors contribute to plant invasiveness?
Invasive species have a significant influence on human health, economics, biodiversity, and ecosystem function in many areas of the world. There has been a great deal of interest in identifying characteristics that promote plant invasiveness as this may facilitate prediction of future invasions, determine the best ways to control invasive species, and help understand the impact of invasive species on native systems. Our current work on invasiveness examines patterns of resource use efficiency and phenotypic plasticity for functional traits related to resource acquisition. Click here for a Nature podcast highlighting some of this research.
Using functional traits to restore invaded ecosystems
Comparing the functional traits of invasive and native species may identify ways to promote the growth of native species and/or curtail the growth of invasive species. This information can be used by resource managers to prioritize areas for invasive species control and to evaluate the potential for resource manipulation (light, nutrient, water availability) as a restoration strategy. Our current work in Hawaii and Mediterranean-climate ecosystems (including California, Australia, South Africa and Spain) focuses on comparing plant functional traits between invasive and native species to identify which native species can outperform invasive species and what environmental conditions are required to favor the growth of natives over invasives during restoration.
Laughlin DC, Chalmandrier L, Joshi C, Renton M, Dwyer JM, Funk JL (2018) Generating species assemblages for ecological restoration and experimentation: a new method that simultaneously converges on average trait values and maximizes functional diversity Methods in Ecology and Evolution doi: 10.1111/2041-210X.13023
Nguyen MA, Larson JE, Blair M, Hardwick D, Khurana N, Kim JS, Rosenfield M, Funk JL (2017) Rapid root responses of seedlings exposed to a postdrought water pulse American Journal of Botany 104:1816-1824
Funk JL, Nguyen M, Standish RJ, Stock WD, Valladares F (2017) Global resource acquisition patterns of invasive and native plant species do not hold at the regional scale in Mediterranean type ecosystems Biological Invasions 19:1143–1151
Wolf AA, Funk JL, Menge DNL (2017) The symbionts made me do it: Legumes are not hardwired for high nitrogen concentrations but incorporate more nitrogen in the presence of bacterial partners New Phytologist 213: 690–699
Funk JL, Larson JE, Ames G, Butterfield B, Cavender-Bares J, Firn J, Laughlin DC, Sutton-Grier A, Williams L, Wright J (2017) Revisiting the Holy Grail: Using plant functional traits to understand ecological processes Biological Reviews 92:1156–1173
Kimball S, Funk JL, Spasojevic MJ, Suding KN, Parker S, Goulden ML (2016) Can functional traits predict plant community response to global change? Ecosphere 7(12):e01602. 10.1002/ecs2.1602
Funk JL, Wolf AA (2016) Testing the trait-based community framework: do functional traits predict competitive outcomes? Ecology 97:2206–2211
Larson JE, Funk JL (2016) Regeneration: An overlooked aspect of trait-based plant community assembly models Journal of Ecology 104:1284–1298
Nguyen M, Ortega AE, Nguyen Q, Kimball S, Goulden M, Funk JL (2016) Evolutionary responses of grassland species to variation in precipitation and soil nitrogen Journal of Ecology 104:979-986
Larson JE, Funk JL (2016) Seedling root responses to soil moisture and the identiﬁcation of a belowground trait spectrum across three growth forms New Phytologist 210:827-838
Funk JL, Standish RJ, Stock WD, Valladares F (2016) Plant functional traits of dominant native and invasive species in Mediterranean-climate ecosystems Ecology 97:75-83
Madliger CL, Cooke SJ, Crespi EJ, Funk JL, Hultine KR, Hunt KE, Rohr JR, Sinclair BJ, Suski CD, Willis CKR, Love OP (2016) Success stories and emerging themes in conservation physiology Conservation Physiology 4: doi: 10.1093/conphys/cov057
Menge DNL, Wolf AA, Funk JL (2015) Diversity of nitrogen fixation strategies in Mediterranean legumes Nature Plants doi:10.1038/nplants.2015.64
Funk JL (2015) Invasive species: A global problem in need of a global solution BioScience 65:623-624
Funk JL, Rakovski CS, Macpherson JM (2015) On the analysis of phylogenetically paired designs Ecology and Evolution 5:940–947
Funk JL, Hoffacker MK, Matzek V (2015) Summer irrigation, grazing and seed addition differentially influence community composition in an invaded serpentine grassland Restoration Ecology 23:122–130
Standish RJ, Hobbs RJ, Mayfield MM, Bestelmeyer BT, Suding KN, Battaglia LL, Eviner V, Hawkes CV, Temperton VM, Cramer VA, Harris JA, Funk JL, Thomas PA (2014) Resilience in ecology: Abstraction, distraction, or where the action is? Biological Conservation 177:43–51
Funk JL, Matzek V, Bernhardt M, Johnson D (2014) Broadening the case for invasive species management to include impacts on ecosystem services BioScience 64:58-63
Funk JL (2013) The physiology of invasive plants in low-resource environments Conservation Physiology 1: doi:10.1093/conphys/cot026
Funk JL, Cornwell WK (2013) Leaf traits within communities: context may affect the mapping of traits to function Ecology 94:1893–1897
Matzek V, Covino J, Funk JL, Saunders M (2013) Closing the knowing–doing gap in invasive plant management: accessibility and interdisciplinarity of scientiﬁc research Conservation Letters doi: 10.1111/conl.12042
Funk JL, Glenwinkel LA, Sack L (2013) Differential allocation to photosynthetic and non-photosynthetic nitrogen fractions among native and invasive species PLoS ONE 8(5):e64502. doi:10.1371/journal.pone.0064502
Funk JL, Amatangelo KL (2013) Physiological mechanisms drive differing foliar calcium content in ferns and angiosperms Oecologia 173:23–32
Drenovsky RE, Grewell BJ, D’Antonio CM, Funk JL, James JJ, Molinari N, Parker IM, Richards CM (2012) A functional trait perspective on plant invasion Annals of Botany 110: 141–153
Steers RJ, Funk JL, Allen EB (2011) Can resource-use traits predict native vs. exotic plant success in carbon amended soils? Ecological Applications 21:1211-1224
Funk JL, Throop HL (2010) Enemy release and plant invasion: patterns of defensive traits and leaf damage in Hawaii Oecologia 162:815-823
Funk JL, Zachary VA (2010) Physiological responses to short-term water and light stress in native and invasive plant species in southern California Biological Invasions 12:1685-1694
Funk JL, McDaniel S (2009) Altering light availability to restore invaded forest: the predictive role of plant traits Restoration Ecology 18:865-872
Funk JL, Cleland EE, Suding KN, Zavaleta ES (2008) Restoration through re-assembly: plant traits and invasion resistance Trends in Ecology and Evolution 23:695-703
Funk JL (2008) Differences in plasticity between invasive and native plants from a low resource environment Journal of Ecology 96:1162-1173
Funk JL, Vitousek PM (2007) Resource use efficiency and plant invasion in low-resource systems Nature 446:1079-1081
Funk JL, Jones CG, Lerdau MT (2007) Leaf- and shoot-level plasticity in response to varying nutrient and water availability Tree Physiology 27:1731-1739
Funk JL (2005) Hedychium gardnerianum invasion into Hawaiian montane rainforest: interactions among litter quality, decomposition rate, and soil nitrogen availability Biogeochemistry 76:441-451
- Megan Blair was an undergraduate researcher from 2016-2018. Megan's honors thesis examined the drought tolerance of Mediterranean herbs (manuscript in prep). She also worked on a group project exploring how roots of several coastal sage scrub species respond to precipitation pulses (Nguyen et al. 2018).
- Nilsha Khurana was an undergraduate researcher from 2016-2018. Nilsha's honors thesis examined leaf traits in legume species that differ in nitrogen fixation strategy. She also worked on a group project exploring how roots of several coastal sage scrub species respond to precipitation pulses (Nguyen et al. 2018).
- Marc Rosenfield was an undergraduate researcher from 2013-2016 and a research associate from 2017-2018. Marc contributed to a number of projects (e.g., Nguyen et al. 2018) and has one paper in review. He is currently pursuing a PhD with at George Washington University.
- Monica Nguyen was an undergraduate researcher from 2012-2015 and a research associate from 2015-2017. Monica contributed to a number of projects and published three papers while in the lab (Nguyen et al. 2016, Funk et al. 2016, Nguyen et al. 2018).
- Julie Larson was a research associate in the lab from 2013-2016. She contributed to a number of projects that focused on how plants respond to changes in water availability (Larson & Funk 2016 New Phytologist, Larson & Funk Journal of Ecology). She is currently pursuing a PhD in Ecology at University of Colorado.
- Joanne Kim was an undergraduate researcher from 2014-2016. She spearheaded a project focusing on how roots of several coastal sage scrub species respond to precipitation pulses (Nguyen et al. 2018).
- Kurt Nguyen was an undergraduate researcher from 2014-2016. With Monica Nguyen and Amy Ortega, he studied how two invasive grass species responded evolutionarily to altered precipitation and soil nitrogen availability (Nguyen et al. 2016). He is currently pursuing a PhD in Entomology at Texas A&M.
- Amy Ortega was an undergraduate researcher from 2012-2015. With Monica Nguyen and Kurt Nguyen, Amy studied how two invasive grass species responded evolutionarily to altered precipitation and soil nitrogen availability (Nguyen et al. 2016).
- Luke Sanborn was an undergraduate researcher from 2013-2015. Luke examined how glutamine synthetase activity regulates nitrogen resorption from senescing leaves.
- Hannah Inman was an undergraduate researcher from 2012-2014. With Kim Cyphers, she studied how leaf and soil traits influence litter decomposition.
- Madison Hoffacker was an undergraduate researcher from 2010-2013. She studied the effectiveness of summer irrigation as a restoration tool in invaded serpentine grassland. Her results were published in Restoration Ecology (Funk et al. 2015).
- Matt Bernhardt was an undergraduate researcher from 2011-2012. He conducted a survey of Weed Management Area chairs in California to determine the impact of state budget cuts on weed management. His results are published in Bioscience (Funk et al. 2013).
- Kim Cyphers was an undergraduate researcher from 2008-2010. She studied how leaf and soil traits influence litter decomposition.
- Lori Glenwinkel was a research technician in the lab from 2008-2010. She is currently pursuing her PhD in Molecular and Cell Biology at Columbia University.
- Ginny Zachary was a research technician in the lab from 2007-2008. She is currently pursuing a degree in nursing at CSU Los Angeles.
Training tomorrow's scientists
Chapman University has partnered with Orange High School to create an innovative research program to engage students who are under-represented in the sciences. Every semester, 10 students from Orange High School conduct hands-on research at Chapman University, including data collection, sample processing, and data analysis. Students conduct research with Dr. Jennifer Funk and Dr. Jason Keller, Associate Professors in the Schmid College of Science and Technology. Students are selected and mentored by Ms. Amelia Strickland, science teacher at Orange High School.
In previous years, students have participated in two research projects. With Dr. Funk, students analyzed leaf nitrogen content to determine how water availability affects leaf traits. With Dr. Keller, students analyzed soil carbon to determine how climate change alters soil carbon cycling. We are excited to see this program grow!