ABOUT

Tracing how molecules and energy flow within ecosystems remains central to fundamental ecological theory and provides insight into the adaptive capacity of individuals and species. I combine ecotoxicology, endocrinology, and stable isotope analysis to study ecological niche variation, explore how nutrients are allocated to growth and reproduction, assess how resource/habitat use and physiology influence pollutant loads and fitness of individuals, and trace how free-ranging organisms interact with their environment to maintain their water balance. Over the next five years, I aim to continue to develop and enhance cutting-edge biochemical tracer techniques to better bridge the ecological and physiological factors that enable organisms to respond to environmental change.

Please see my research and publications pages for details. 

I completed my undergraduate, honors, M.S., and Ph.D. degrees in the Department of Zoology & Entomology at the University of Pretoria (UP) in South Africa (SA). I gained extensive field and laboratory experience through collaborations with various institutions, conducting research on a variety of taxa. I performed my laboratory work at the University of Pretoria, SA (bulk tissue stable isotopes), the Central Analytical Facility at the University of Stellenbosch, SA (Hormones: Ultraperformance Convergence Chromatography), and the Centre for Stable Isotopes, University of New Mexico (UNM), USA (Amino acid-specific stable isotopes; Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry).

My early career work as an undergraduate focused on assessing the invasive potential of aquatic invaders in SA using ecological niche modeling, stomach content analyses, and Bayesian stable isotope mixing models, which resulted in four publications (Lübcker et al. 2014. 2016; Woodborne et al. 2012; Dawbroski et al. 2014). My training expanded into marine ecosystems after I was appointed as Field Biologist by the Department of Environmental Affairs for the Marion Island Marine Mammal Program. I spent 13 months on Marion Island conducting research on marine vertebrates. The scientific experience I gained is immeasurable and I commenced a new long-term program of isotope-based research for the project (https://www.marionseals.com/), which I used to complete my M.S. (2013-2015, with distinction). During my Ph.D. (2016-2019) as National Research Foundation (NRF) Fellow at UP, I used intrinsic biomarkers (hormones and isotopes) in whiskers and hair to identify physiological mechanisms that individuals use to cope with fasting and to assess how amino acids are transferred between mothers and their fetuses during gestation (Lübcker et al. 2016, 2017, 2020a, b, 2021). My dissertation formed part of the long-term (1983–Present) project on which I am a co-investigator, funded by NRF. One of the overarching goals of this work is to identify how different foraging strategies influence body condition and relate to an alternative, intermittent reproductive pattern identified in phocids over the last three decades of research in different systems. This endeavor combines compound-specific isotope analysis with demographic, telemetry, and steroid data; our preliminary analyses suggest that selection can maintain two different reproductive strategies.

As a postdoctoral fellow at UNM in the Newsome Lab, I have strengthened my training in mass spectrometry and am broadening my horizons across marine and terrestrial ecosystems. Specifically, I’m using amino acid isotope analysis to characterize dynamics in energy flow within and among organisms to aid in the ecological and physiological interpretation of biological tracer data. I’m developing a novel approach to explore the income versus capital continuum of resource allocation to reproduction in reptiles, turtles, birds, and marine mammals with international collaborators. I have also expanded my research to desert ecosystems by co-leading a monthly small mammal trapping program at the Sevilleta Long-Term Ecological Research (SEV-LTER) site in central New Mexico and am collecting blood samples from a guild of reptiles across habitats in the American Southwest, conducted in collaboration with the Museum of Southwestern Biology. The aim is to develop a method based on the analysis of all three stable isotopes of oxygen to quantify the contribution of metabolic water to the total body water pool of free-ranging organisms. In addition to addressing fundamental questions about animal metabolism and comparative physiology, my work also refines the capabilities and limitations of these novel techniques.

As a scientist, educator, and mentor, I pledge to expand diversity, equity, and inclusion of previously underrepresented racial and ethnic groups. I am dedicated to mentoring and teaching the next generation of biologists based on experiential learning; student mentoring is one of the primary reasons why a career in academia appeals to me. The goal is to inspire the next generation of critical thinkers, foster independence, and stimulate creativity.