PhD Research at Aarhus University

For my PhD, I am using digital soil mapping techniques to determine bio-physical regions in Denmark. My project is embedded within the Danish research and development project “ProvenanceDK”. The aim is to characterize terroir-like regional entities by integrating soil properties with topographic and landform attributes together with information on climate variation across Denmark. I am using machine learning, both supervised and unsupervised, with gridded and point data to characterize Denmark into different regions. My work so far has created a terron workflow and yield predictions for winter wheat. I am also working on making tree suitability maps and trying to predict historical crop, livestock, and population density using environmental variables.

Terron Workflow

The first part of my work created terrons. Terrons are defined as areas similar in soil and landscape. There are two approaches to terron mapping. The first was proposed in 2005 by Carré and McBratney, using soil profile data, and the second was by Malone et al. in 2014, using gridded data. My work was to develop a workflow that will automate terron class creation using gridded data. The manuscript is now published and the code has been finalized. A pre-print of the publication and code can be viewed at my github page. A word cloud created from the publication has been uploaded.

Winter Wheat Predictions

The second part of my work used random forest with environmental variables to update the current winter yield prediction for Denmark. After the map was updated, the new map was compared to historical yield potential data from the 17th and 19th century to assess both the spatial and temporal agricultural trends. The manuscript is now published and the journal is open access. A word cloud created from the publication has been uploaded.

Master’s Research at the University of Idaho

The goal of my Master’s thesis was to understand how variation in habitat can promote species richness and trait diversity. The first objective of this project was to link how island ontogeny shapes the number of species found on islands. The second objective was to quantify the association between habitat features and variation in morphology and physiology of species. I am interested in using GIS techniques in biology to help with management decisions in conservation. My thesis can be viewed here.

Species Richness

By using the data available at the Charles Darwin Foundation Datazone, I could test the topographic complexity assumptions that are made in the General Dynamic Model (GDM) of Oceanic Island Biogeography. The assumption is that topographic complexity will follow a hump-shaped curve through an island’s ontogeny. I was testing to see if this assumption is true in the Galapagos and if topographic complexity is incorporated into the model, which measure of complexity should be used. Since there are many different ways to measure topographic complexity, I wanted to know if there is a single measure that should be used to model all taxonomic groups in the Galapagos or if each taxonomic group has a different measure depending on how each group interacts with the landscape.

Trait Diversity

To understand how trait diversity is linked to the habitat where species are found, a well-studied adaptive radiation of the Galapagos islands was used. The endemic land snails of the genus Naesiotus represent the most species rich adaptive radiation of the Galapagos islands with over 60 species currently described. Naesiotus inhabits most islands in the Galapagos from lower elevations that are hot and arid to higher elevations that are cool and humid. Along this environmental gradient, these species exhibit diverse shell sizes and shapes. Although work in this system using phylogenetically-controlled analyses has identified a strong link between shell morphology and ecology, a thorough study of physiological variation within and among species is needed to identify the proximate mechanisms and ultimate causes responsible for ecological diversification. I was linking morphological and physiological changes with environmental variation which will help in understanding why an adaptation would arise and why a lineage has diversified.

The word clouds above were generated from my manuscripts and thesis chapters. This page also has some of my favorite animal photos and a video I made on the fascinating things I saw while in the Galapagos. You can also watch this video on youtube by clicking here.