A Nothofagus leaf from the Miocene Double Hill site in New Zealand.
My primary research interests is plants and how the biosphere has evolved through Earth's history. Originally, I was schooled in Earth Sciences and Geology with a special focus on Paleobiology. But through time my interests broadened from paleobotany to modern plant functional ecology, adaptation, and ecophysiology. My work constitutes a combination of field methods, lab techniques, and computational / statistical analyses. As a geologist, I am particularly fond of fieldwork, but the reality is that the skills that I use the most in my research can best be described as big data analytics applied to paleobotany and terrestrial paleoclimate.
Sebastian Steinig created this song using the AI Suno for our DeepMIP paper on Eocene greening of Australia. Frankly, it does an excellent job explaining what some of my research focuses on. And because I have terrible taste in music, I find it quite catchy as well.
Plants represent the ideal window into the ancient world. Since plants are sessile organisms, their morphology and physiology needs to be fine-tuned to the environment they live in. Abiotic selective pressure is high in plants and as such, we see convergent evolutionary strategies in many traits reflective of the environment. These convergent evolutionary strategies are apparently stable through time, which means that fossil plants can provide key insights into long-lost ancient environments.
My focus is on everything pre-Quaternary, with a special place in my heart for the Triassic period, since this was my gateway drug into paleo-ecology and paleobotany. My PhD research on the other hand was on reconstructing paleoclimate of the Miocene in New Zealand. Since then, there hasn't been a single epoch of the Cenozoic era, or period of the Mesozoic era, that I haven't worked on! I have used fossil plants to reconstruct a wide array of paleoclimate variables, including carbon dioxide levels, temperature, seasonality, and precipitation. I am especially interested in "extinct" climates — the combination of climatic variables that cannot co-exist in the modern world — since these climates are the most interesting puzzles, but may represent the closest analog to future climates
Stained leaf cuticle of a 23-million-year-old Litsea
Guttation observed on an early spring morning in Vitis labrusca
Though starting off as a geologist, I have become increasingly interested in plant ecology and ecophysiology throughout my career. I find that being able to understand how a plant functions in extant environments makes it easier to visualize potential life strategies of fossil plants. Topics that I find particularly interesting are leaf life span, the role of leaf teeth, the relationship between carbon assimilation and water-use efficiency, fire ecology, and enigmatic epidermal structures such as hydathodes and colleters. Recently, I also branched out into a very enjoyable passion project involving native fern species that manage to survive in harsh urban environments in the US northeast.
The foremost analytical technique I developed is a probability-based quantitative paleoclimate reconstruction technique based on the distribution of the nearest living relatives of plants in a fossil assemblage. Simply put: this technique calculates the most likely climatic interval at which all of the plant groups in the assemblage can co-occur. My approach builds on older nearest living relative-based techniques in three key ways: 1) the data is reproducible, as the occurrence data used is derived from publicly available continuously updated metadata, 2) the calculated interval considers all climatic parameters together, rather than separate, and 3) the technique is fully quantitative and probability-based; no subjectivity involved. Any researcher should be able to reproduce this technique in R following the instructions in the papers where I applied it, for example this one. However, I have, at this stage vetted and filtered the modern distributions of >1,000 plant groups. This is probably the most time-consuming part of nearest living relative-based paleoclimate reconstructions and I will add that the analysis is quite sensitive to distribution bias. Therefore, if you'd like me to use my database of vetted plant distributions, or simply like me to run an analysis, feel free to reach out! I'm sure one day I'll get around to publishing that database...
Blooms of a New Zealand endemic mistletoe Peraxilla colensoi
A colony of Asplenium platyneuron on a bridge pillar in Hartford
I am a big fan and very active on the iNaturalist citizen science platform. If you're not familiar, this is a platform where nature lovers from around the world can post their observations (with pictures or sound) and have it identified by a combination of a powerful image recognition AI and experts. I help out people who post pictures of my favorite plant group: ferns. iNaturalist is also how I got interested in ferns growing in urban environments. iNaturalist observations, after being vetted by experts, is included in the Global Biodiversity Information Facility (GBIF), which means that its data can be used for species distribution models, such as the ones that I build for my nearest living relative approach, discussed above. The beauty of this data is that there is a massive amount and diversity of it. For example, using citizen science data, I was able to investigate which are capable of growing in urban environment. Without citizen science data, there would not have been a large enough sample size to draw any conclusions, and the urban environment would not have been recorded to begin with. Currently, I am experimenting a little more with this idea, by expanding my reach to other vascular plants, with my Wall Plants of New England project, trying to answer the question: what are the cornerstones of an urban ecosystem?