Alexandre Demers-Potvin
Project
Determining the effects of climate change and environmental change on terrestrial ecosystems in Late Cretaceous Canada using the fossil faunas and floras of Dinosaur Provincial ParkI am currently in third year of a PhD degree in palaeoecology where I aim to track faunal, climatic and landscape changes throughout the Late Cretaceous Belly River Group (BRG) in Alberta and Saskatchewan. Within this stratigraphic unit, Dinosaur Provincial Park (DPP) is one of the few fossil sites in the world to present three key components of evolutionary palaeoecology. Firstly, DPP is an incredibly rich fossil locality that has yielded thousands of specimens that represent different components of a Late Cretaceous ecosystem, including a currently unmatched abundance of well-preserved dinosaur skeletons spread over 75 km2 of badlands. Secondly, DPP presents robust chronostratigraphic evidence in the form of precise absolute ages for a rock sequence that spans ~1 million years. Lastly, it presents sedimentological evidence of a clear sea level rise throughout that time interval. This makes DPP an ideal system to study ecological and evolutionary trends on a geological time scale with robust spatial and temporal constraints. The first specific aim of my PhD thesis (Aim 1) is to obtain a more precise chronostratigraphic framework of DPP in order to achieve the correlation of all the fossil quarries for which locality data is available (Time component). The second specific aim (Aim 2) is to detect absolute palaeoclimate trends through the time interval spanned by the BRG in DPP (Climate component). The third specific aim (Aim 3) is to track biotic change in DPP with a more complete fossil record and to compare resulting diversity trends with known environmental trends with better-defined relative ages (Diversity component). One of the expected results of my project consists in assembling a geodatabase that will combine all vertebrate, invertebrate and plant fossil specimens known from DPP while including their precise locality data for the first time. These occurrences will be plotted on an orthomosaic assembled from drone photographs of the Park’s outcrops taken during fieldwork in August 2021. The section that covers the ~6.25-km2 area of badlands surveyed to date is close to completion and will present the Park’s stratigraphic sequence in unprecedented detail on a large spatial scale, thus contributing to Aim 1. However, many of the specimens found in the area covered by last summer’s expedition have not been identified. This means I must travel to museum collections to record as many of these as possible in the dataset I am currently building to fulfill Aim 3. I anticipate my PhD to result in one of the most detailed fossil databases at relatively small spatial and temporal scales. It could complement the Paleobiology Database to study the evolution of a well-known extinct terrestrial ecosystem with reduced time-averaging.
Keywords
paleoecology, paleoclimatology, paleobotany, paleontology, beta-diversity, alpha-diversity, Ecological NetworksPublications
1- Palaeoclimatic reconstruction for a Cenomanian‐aged angiosperm flora near Schefferville, LabradorDemers‐Potvin, Alexandre V., Hans C. E. Larsson,
2019 Palaeontology
2- Wing morphology of a new Cretaceous prayin g mantis solves the phylogenetic jigsaw of early‐diverging extant lineages
Demers‐Potvin, Alexandre V., Hans C.E. Larsson, Mario Cournoyer, Olivier Béthoux
2021 Systematic Entomology
3- First North American occurrence of hairy cicadas discovered in a Late Cretaceous (Cenomanian) exposure from Labrador, Canada
Demers-Potvin, Alexandre, Jacek Szwedo, Cassia Paragnani, Hans Larsson
2020 Acta Palaeontologica Polonica
