Biology subjects

Tremblay, F.

Publications and source records attributed to Tremblay, F..

4 recordsLinked to original sources

bioRxiv2025

Legal Harvest of Shorebirds and Resident Game Birds on a Caribbean island: A Martinique Case Study

Legal hunting practiced under regulatory frameworks is not always assessed for its sustainability. The lack of harvest data is of particular concern in the case of birds occurring on islands. Resident species on islands often exhibit limited geographic ranges and inherently small population sizes, rendering them particularly susceptible to environmental and anthropogenic threats. Islands also support seasonally fluctuating populations of migratory species, providing essential habitats for stopovers and non-breeding periods. Within this context, the sustainability of gamebird harvest practiced on islands within a regulatory framework needs to be evaluated to inform management and prevent negative impacts on populations. Here, we present a case study of an island-wide assessment of bird hunting estimates, based on data available from a legal hunting program, in Martinique, a tropical oceanic island part of the Caribbean biodiversity hotspot. Our objectives were to determine the magnitude of gamebird harvest, track changes in harvest levels over time, and assess harvest sustainability. Our assessment, which is based on hunting logbooks and hunter surveys between the 2012-2013 and 2021-2022 hunting seasons, provides harvest estimates for two groups of migratory species, shorebirds (Charadriidae, Scolopacidae) and teals (Anatidae), and two groups of resident species (Columbidae and Mimidae). In Martinique, harvest management measures, combined with increased hunters engagement and enforcement of regulations, has led more stringent harvest regulations, improved compliance from hunters, and a reduction of Martiniques national shorebird harvest. However, considering continued and rapid shorebirds population declines across the Western Atlantic flyway, shorebird harvest assessment at the flyway level remains a priority.

ecology↗

bioRxiv2022

The role of wingbeat frequency and amplitude in flight power

Body-mounted accelerometers provide a new prospect for estimating power use in flying birds, as the signal varies with the two major kinematic determinants of aerodynamic power: wingbeat frequency and amplitude. Yet wingbeat frequency is sometimes used as a proxy for power output in isolation. There is therefore a need to understand which kinematic parameter birds vary and whether this is predicted by flight mode (e.g., accelerating, ascending/descending flight), speed or morphology. We investigate this using high-frequency acceleration data from (i) 14 species flying in the wild, (ii) two species flying in controlled conditions in a wind tunnel and (iii) a review of experimental and field studies. While wingbeat frequency and amplitude were positively correlated, R2 values were generally low, supporting the idea that parameters can vary independently. Indeed, birds were more likely to modulate wingbeat amplitude for more energy-demanding flight modes, including climbing and take-off. Nonetheless, the striking variability even within species and flight types, highlights the complexity of describing the kinematic relationships, which appear sensitive to both the biological and physical context. Notwithstanding this acceleration metrics that incorporate both kinematic parameters should be more robust proxies for power than wingbeat frequency alone.

biophysics↗

bioRxiv2021

Ecological inference using data from accelerometers needs careful protocols

O_LIAccelerometers in animal-attached tags have proven to be powerful tools in behavioural ecology, being used to determine behaviour and provide proxies for movement-based energy expenditure. Researchers are collecting and archiving data across systems, seasons and device types. However, in order to use data repositories to draw ecological inference, we need to establish the error introduced according to sensor type and position on the study animal and establish protocols for error assessment and minimization. C_LIO_LIUsing laboratory trials, we examine the absolute accuracy of tri-axial accelerometers and determine how inaccuracies impact measurements of dynamic body acceleration (DBA), as the main acceleration-based proxy for energy expenditure. We then examine how tag type and placement affect the acceleration signal in birds using (i) pigeons Columba livia flying in a wind tunnel, with tags mounted simultaneously in two positions, (ii) back- and tail-mounted tags deployed on wild kittiwakes Rissa tridactyla. Finally, we (iii) present a case study where two generations of tag were deployed using different attachment procedures on red-tailed tropicbirds Phaethon rubricauda foraging in different seasons. C_LIO_LIBench tests showed that individual acceleration axes required a two-level correction (representing up to 4.3% of the total value) to eliminate measurement error. This resulted in DBA differences of up to 5% between calibrated and uncalibrated tags for humans walking at different speeds. Device position was associated with greater variation in DBA, with upper- and lower back-mounted tags in pigeons varying by 9%, and tail- and back-mounted tags varying by 13% in kittiwakes. Finally, DBA varied by 25% in tropicbirds between seasons, which may be attributable to tag attachment procedures. C_LIO_LIAccelerometer accuracy, tag placement, and attachment details critically affect the signal amplitude and thereby the ability of the system to detect biologically meaningful phenomena. We propose a simple method to calibrate accelerometers that should be used prior to deployments and archived with resulting data, suggest a way that researchers can assess accuracy in previously collected data, and caution that variable tag placement and attachment can increase sensor noise and even generate trends that have no biological meaning. C_LI

animal behavior and cognition↗

bioRxiv2019

Polygenic risk scores of several subtypes of epilepsies in a founder population

ImportanceEpilepsy is defined as a group of neurological disorders characterized by epileptic seizures, brief episodes of symptoms that are caused by abnormal or excessive neuronal activity in the brain. Epilepsy affects around 3 percent of individuals. In the past 10 years, many groups have been working to better understand the complex genetic mechanisms underlying epilepsy. Together, they studied many different genetic mechanisms, but there is still a substantial missing heritability component in epilepsy genetics.\n\nObjectiveHere, we used polygenic risk scores (PRS) to quantify the cumulative effects of a number of variants, which may individually have a very small effect on susceptibility.\n\nDesignWe calculated PRS in 522 French-Canadian epilepsy patients divided into seven subtypes and French-Canadian controls.\n\nSettingAll study participants (cases and controls) were selected based on their French-Canadian ancestry.\n\nParticipantsThe epilepsy cohort was composed of families of at least three affected individuals with Idiopathic Generalized Epilepsy (IGE) or Non-acquired Focal Epilepsy (NAFE) previously collected and diagnosed by neurologists following the International League Against Epilepsy (ILAE) criteria.\n\nExposuresAll samples were processed on a common genotyping array.\n\nMain outcomes and ResultsWe show that the area under the curve (AUC) is almost always slightly greater than 0.5, especially in patients with IGE and subtypes. We also looked at the association of the PRS with the different phenotypes using a linear mixed effects model estimated by generalized estimating equation (GEE) with the pairwise identity-by-descent (IBD) matrix as a random effect. P-values of GEE were consistent with AUC calculations.\n\nConclusions and RelevanceGlobally, we support the notion that PRS and SNP-based heritability provide reliable measures to rightfully estimate the contribution of genetic factors to the pathophysiological mechanism of epilepsies, but further studies are needed on PRS before they can be used clinically.

genetics↗