Kimberly Komatsu La Pierre
Graduate Student
Department of Ecology and Evolutionary Biology
Yale University
OML 426
New Haven, CT 06511, USA
Email: kimberly.lapierre@yale.edu
Education
2013 Ph.D (expected) Yale University, Ecology and Evolutionary Biology
2007 B.S. University of California - Irvine, Ecology and Evolutionary Biology
Kimberly's CV
Research Interests
I am interested in the relative impacts of bottom-up and top-down controls and their interactive effects on grassland structure and function. There has been longstanding debate over whether terrestrial systems are under bottom-up or top-down control. Currently, it is generally accepted that both bottom-up and top-down forces are important in structuring grassland communities. However, debate continues over the relative strengths of these forces and their potential interactive effects. Because the relative and interactive effects between bottom-up and top-down forces likely vary in space and time and interact in complex ways, it is important to examine these effects in tandem and across broad spatial scales in order to develop a more general framework of their control over grassland systems.
Within the broad framework of top-down versus bottom-up controls, I am interested in examining: (1) the relative impacts and interactions of vertebrate herbivores and nutrient availability on primary productivity and plant diversity within grasslands; (2) the relative impacts of vertebrate versus invertebrate herbivores on grasslands; (3) the effects of nutrient additions and vertebrate herbivore removal on the invertebrate community in grasslands; and (4) the factors influencing woody encroachment into grasslands and how these factors vary over the multiple demographic stages of encroachment.
I am working to address these questions at three study sites spanning the natural east-west precipitation gradient of the central Great Plains, with sites in shortgrass steppe (Shortgrass LTER, CO; SGS), mixed grass prairie (Saline Experimental Range, western KS; SER), and tallgrass prairie (Konza LTER, northeastern KS; KNZ). This will enable me to examine how top-down and bottom-up controls interact with the effects of water limitation.
My work is being conducted within the framework of the Nutrient Network, which is a unique network of coordinated experiments within which soil nutrient levels and herbivore presence are being co-manipulated to examine the relative importance of multiple resource limitation and top-down controls of herbaceous systems.
Previous Research
Strong feeding preference of an exotic generalist herbivore for an exotic forb*
The invasional meltdown framework suggests that the invasion of a plant species may be facilitated by the co-invasion of a non-native generalist herbivore from the same home range. Our objective was to determine the role of herbivory by the non-native snail Otala lactea in structuring California grassland communities. We conducted two experiments to examine the feeding preferences of O. lactea for eight representative grassland species. Overall, O. lactea preferred Brassica nigra, a non-native forb, over all other species tested. Field monocultures of B. nigra supported significantly higher snail densities than monocultures of any of the other species tested. O. lactea also preferred B. nigra over all other species tested in controlled laboratory feeding trials. However, based on trait comparisons of each of the eight grassland species (relative growth rate and C:N ratios), we cannot pinpoint the preference for B. nigra to a basic nutritional requirement on the part of the herbivore or an allocation to defense on the part of the plants. The preference may, however, be due to a nutritional requirement unique to this snail species. Thus, we found strong evidence of selective herbivory on a non-native plant species by a non-native herbivore, contrary to the predictions of the invasional meltdown hypothesis.
Invasion increases activities of soil microbial extracellular enzymes involved in carbon, nitrogen, and phosphorous processing in Coastal Sage Scrub*
While the invasions of exotic plant species are thought to alter ecosystem functioning, the effects of most exotic plant species on soil microbial function are not well understood. Cynara cardunculus, an exotic herbaceous, perennial thistle, is considered a serious invader of Coastal Sage Scrub (CSS) in southern California. Simultaneous increases in abundance of the native, perennial shrub Baccharis pilularis have also become a threat to CSS diversity. We contrasted the effects of invasion by woody and non-woody species into CSS on microbial community function, as characterized by soil microbial extracellular enzyme activity. In addition, extracellular enzyme activity was monitored following herbicide-control of C. cardunculus to determine whether soil community function would return to the native state. We compared effects associated with the two invading species with those associated with Artemesia california, a native shrub typical of intact CSS communities.
Activities of soil microbial extracellular enzymes involved in processing organic carbon (β-D-cellobiohydrolase and peroxidase), nitrogen (N-acetyl-β-glucosaminidase), and phosphorous (acid phosphatase) were significantly higher in soils associated with either C. cardunculus or B. pilularis than those associated with A. californica. The higher extracellular enzyme activities found in soils associated with C. cardunculus and B. pilularis may be due to higher relative growth rates or litter inputs of these two species. High terpinoid levels in A. californica's litter may also be partially responsible for the observed difference in extracellular enzyme activity between species. The activities of β-D-cellobiohydrolase, peroxidase, N-acetyl-β-glucosaminidase, and acid phosphatase significantly increased following application of herbicide to C. cardunculus. This increase in activity was likely a response of the microbial community to the high levels of dead C. cardunculus tissue remaining in the system following the herbicide treatment. The change in microbial function, combined with gaps left in the plant cover by removal of C. cardunculus, may help fuel subsequent invasion of these and other exotic species into Coastal Sage Scrub in the future.
*past research was conducted with Dr. Katharine N. Suding at the University of California, Irvine
Publications
La Pierre, KJ, Yuan, S, Chang, CC, Avolio, MA, Hallett, LM, Schreck, T, Smith, MD. 2011. Explaining temporal variation in aboveground productivity in a mesic grassland: the role of climate and flowering. Journal of Ecology. 99(5): 1250-1262.Adler, PB, Seabloom, E, Borer, E, Hillebrand, H, Hautier, Y, Hector, A, OÕHalloran, LR, Harpole, WS, Anderson, TM, Bakker, JD, Biederman, LA, Brown, CS, Buckley, Y, Calabrese, L, Chu, C, Clealand, E, Collins, SL, Cottingham, KL, Crawley, MJ, Davies, KF, DeCrappeo, NM, Fay, PA, Firn, J, Frater, P, Gasarch, EI, Gruner, D, Hagenah, N, Hillerislambers, J, Humphries, H, Jin, VL, Kay, A, Klein, JA, Knops, J, Kirkman, K, La Pierre, KJ, Lambrinos, J, Leakey, ADB, Li, W, MacDougall, A, McCulley, RL, Melbourne, BA, Mitchell, CE, Moore, J, Morgan, J, Mortenson, B, Orrock, J, Prober, S, Pyke, DA, Risch, A, Schuetz, M, Stevens, C, Sullivan, LL, Wang, G, Wragg, P, Wright, J. 2011. Productivity is a poor predictor of plant species richness. Science. 333(6050): 1750-1753.
Firn, J, Moore, JL, MacDougall, AS, Borer, ET, Seabloom, EW, HilleRisLambers, J, Harpole, WS, Cleland, EE, Brown, CS, Knops, JMH, Prober, SM, Pyke, DA, Farrell, KA, Bakker, JD, O'Halloran, LR, Adler, PB, Collins, SL, D'Antonio, CM, Crawley, MJ, Wolkovich, EM, La Pierre, KJ, Melbourne, BA, Hautier, Y, Morgan, JW, Leakey, ADB, Kay, A, McCulley, R, Davies, KF, Stevens, CJ, Chu, CJ, Holl, KD, Klein, JA, Fay, PA, Hagenah, N, Kirkman, KP, and Buckley, YM. 2011. Abundance of introduced species at home predicts abundance away in herbaceous communities. Ecology Letters 14:274-281.
La Pierre, KJ, Harpole, WS, Suding, KN. 2010. Strong feeding preference of an exotic generalist herbivore for an exotic forb: a case of invasional antagonism. Biological Invasions.12(9): 3025-3031.