Titouan Lorieul

Dr. Titouan Lorieul

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Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 March 2019 in Applications in Plant Sciences
Verified
Journal Article
Open access
PDF file
TLTitouan Lorieul
Titouan Lorieul
KPKatelin D. Pearson
Katelin D. Pearson
EEElizabeth Ellwood
Elizabeth Ellwood
HGHervé Goëau
Hervé Goëau
JMJean‐Francois Molino
Jean‐Francois Molino
AJAlexis Joly
Alexis Joly
Premise of the Study: Phenological annotation models computed on large‐scale herbarium data sets were developed and tested in this study.Methods: Herbarium specimens represent a significant resource with which to study plant phenology. Nevertheless, phenological annotation of herbarium specimens is time‐consuming, requires substantial human investment, and is difficult to mobilize at large taxonomic scales. We created and evaluated new methods based on deep learning techniques to automate annotation of phenological stages and tested these methods on four herbarium data sets representing temperate, tropical, and equatorial American floras.Results: Deep learning allowed correct detection of fertile material with an accuracy of 96.3%. Accuracy was slightly decreased for finer‐scale information (84.3% for flower and 80.5% for fruit detection).Discussion: The method described has the potential to allow fine‐grained phenological annotation of herbarium specimens at large ecological scales. Deeper investigation regarding the taxonomic scalability of this approach is needed.

15 September 2020
Verified
Book Chapter
Closed access
PDF file
AJAlexis Joly
Alexis Joly
HGHervé Goëau
Hervé Goëau
SKStefan Kahl
Stefan Kahl
BDBenjamin Deneu
Benjamin Deneu
MSMaximillien Servajean
Maximillien Servajean
HMHenning Müller
Henning Müller



26 September 2024 in Peer Community Journal
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Journal Article
Closed access
PDF file
GMGaétan Morand
Gaétan Morand
AJAlexis Joly
Alexis Joly
TRTRISTAN ROUYER
TRISTAN ROUYER
TLTitouan Lorieul
Titouan Lorieul
JBJulien Barde
Julien Barde
As biodiversity plummets due to anthropogenic disturbances, the conservation of oceanic species is made harder by limited knowledge of their distributions and migrations. Indeed, tracking species distributions in the open ocean is particularly challenging due to the scarcity of observations and the complex and variable nature of the ocean system. In this study, we propose a new method that leverages deep learning, specifically convolutional neural networks (CNNs), to capture spatial features of environmental variables. This novelty eliminates the need to predefine these features before modelling and creates opportunities to discover unexpected correlations. Our aim is to present the results of the first trial of this method in the open ocean, discuss limitations and provide feedback for future improvements or adjustments. In this case study, we considered 38 taxa comprising pelagic fishes, elasmobranchs, marine mammals, marine turtles and birds. We trained a model to predict probabilities from the environmental conditions at any specific point in space and time, using species occurrence data from the Global Biodiversity Information Facility (GBIF) and environmental data from various sources. These variables included sea surface temperature, chlorophyll concentration, salinity and fifteen others. During the testing phase, the model was applied to environmental data at locations where species occurrences were recorded. The classifier accurately predicted the observed taxon as the most likely taxon in 69% of cases and included the observed taxon among the top three most likely predictions in 89% of cases. These findings show the adequacy of deep learning for species distribution modelling in the open ocean. Additionally, this purely correlative model was then analysed with explicability tools to understand which variables had an influence on the model’s predictions. While variable importance was species-dependent, we identified finite-size Lyapunov exponents (FSLEs), sea surface temperature, pH and salinity as the most influential variables, in that order. These insights can prove valuable for future species-specific ecology studies.

16 February 2022 in Plants
Verified
Journal Article
Open access
PDF file
HGHervé Goëau
Hervé Goëau
TLTitouan Lorieul
Titouan Lorieul
PHPatrick Heuret
Patrick Heuret
AJAlexis Joly
Alexis Joly
PBPierre Bonnet
Pierre Bonnet
A better knowledge of tree vegetative growth phenology and its relationship to environmental variables is crucial to understanding forest growth dynamics and how climate change may affect it. Less studied than reproductive structures, vegetative growth phenology focuses primarily on the analysis of growing shoots, from buds to leaf fall. In temperate regions, low winter temperatures impose a cessation of vegetative growth shoots and lead to a well-known annual growth cycle pattern for most species. The humid tropics, on the other hand, have less seasonality and contain many more tree species, leading to a diversity of patterns that is still poorly known and understood. The work in this study aims to advance knowledge in this area, focusing specifically on herbarium scans, as herbariums offer the promise of tracking phenology over long periods of time. However, such a study requires a large number of shoots to be able to draw statistically relevant conclusions. We propose to investigate the extent to which the use of deep learning can help detect and type-classify these relatively rare vegetative structures in herbarium collections. Our results demonstrate the relevance of using herbarium data in vegetative phenology research as well as the potential of deep learning approaches for growing shoot detection.