Biology subjects

Marchand, P.

Publications and source records attributed to Marchand, P..

8 recordsLinked to original sources

bioRxiv2026

Integrating multi-host modelling with empirical wildlife-livestock contacts reveals an essential population in a pathogen reservoir

Infections at the animal-human or wildlife-livestock interfaces have severe health and socio-economic consequences. Combined with empirical data, mathematical models can contribute to a better understanding of the reservoirs of these infections, which is a priority for mitigating their impact by using appropriate management interventions. Taking brucellosis in the Bargy massif (French Alps) as an example of a zoonosis at the wildlife-livestock interface, we developed and calibrated a multi-host model integrating data on direct and environment-mediated cross-species contacts from field observations. Estimates of the basic reproduction number (R0) allowed to identify the population of Alpine ibex (Capra ibex) and its environment as an essential host in the reservoir, driving both pathogen maintenance (within-species R0[≥]1: 1.66, 95% credible interval: 1.42-2.03) and its transmission to livestock (between-species R0>0: 0.035, 0.01-0.05). Our approach can be adapted to other multi-host pathogens, which will contribute to improve the understanding and management of these complex systems.

ecology↗

bioRxiv2023

Reproductive tactics, birth timing and the trade-off between risk avoidance and foraging in an income breeder

The behavioural trade-off between foraging and risk avoidance is expected to be particularly acute during gestation and lactation, when the energetic demands of reproduction peak. We investigated how female roe deer, an income breeding ungulate, adjust their management of this trade-off during the birth period in terms of foraging activity and habitat use. We showed that activity levels of reproductive females more than doubled immediately following parturition, when energy demand is highest. Moreover, reproductive females increased their use of open habitat during daytime and ranged closer to roads, but slightly further from refuge woodland, compared to non-reproductive females. However, these post-partum modifications in behaviour were particularly pronounced in late-parturient females who adopted a more risk prone tactic, presumably to compensate for the fitness handicap of their late-born offspring. In income breeders, individuals that give birth late may be forced to trade risk avoidance for resource acquisition during peak allocation to reproduction, likely with significant fitness consequences.

animal behavior and cognition↗

bioRxiv2023

Using accelerometers to infer behaviour of cryptic species in the wild

Accelerometery is revolutionising the field of behavioural ecology through its capacity to detect the fine-scale movements of animals resulting from their behaviour. Because it is often difficult to infer the behaviour of wildlife on a continuous basis, particularly for cryptic species, accelerometers potentially provide powerful tools for remote monitoring of their behavioural responses to the environment. The goal of this study was to provide a detailed, calibrated methodology, including practical guidelines, to infer the behaviour of free-ranging animals from acceleration data. This approach can be employed to reliably infer the time budget of species that are difficult to observe in certain environments or at certain times of the day. To this end, we trained several behavioural classification algorithms with accelerometer data obtained on captive roe deer, then validated these algorithms with data obtained on free-ranging roe deer, and finally predicted the time-budgets of a substantial sample of unobserved free-ranging roe deer in a human-dominated landscape. The best classification algorithm was the Random Forest which predicted five behavioural classes with a high overall level of accuracy ({approx} 90%). Except for grooming (34-38%), we were able to predict the behaviour of free-ranging roe deer over the course of a day with high accuracy, in particular, foraging head down, running, walking and immobile (68-94%). Applied to free-ranging individuals, the classification allowed us to estimate, for example, that roe deer spent about twice as much time foraging head-down, walking or running during dawn and dusk than during daylight or night-time. By integrating step by step calibration and validation of accelerometer data prior to application in the wild, our approach is transferable to other free-ranging animals for predicting key behaviours in cryptic species.

animal behavior and cognition↗

bioRxiv2023

Identifying the environmental drivers of corridors and predicting connectivity between seasonal ranges in multiple populations of Alpine ibex (Capra ibex) as tools for conserving migration

Seasonal migrations are central ecological processes connecting populations, species and ecosystems in time and space. Land migrations, such as those of ungulates, are particularly threatened by habitat transformations and fragmentation, climate change and other environmental changes caused by anthropogenic activities. Mountain ungulate migrations are neglected because they are relatively short, although traversing highly heterogeneous altitudinal gradients particularly exposed to anthropogenic threats. Detecting migration routes of these species and understanding their drivers is therefore of primary importance to predict connectivity and preserve ecosystem functions and services. The populations of Alpine ibex Capra ibex, an iconic species endemic to the Alps, have all been reintroduced from the last remnant source population. Because of their biology and conservation history, Alpine ibex populations are mostly disconnected. Hence, despite a general increase in abundance and overall distribution range, their conservation is strictly linked to the interplay between external threats and related behavioral responses, including space use and migration. By using 337 migratory tracks from 425 GPS-collared individuals from 15 Alpine ibex populations distributed across their entire range, we (i) identified the environmental drivers of movement corridors in both spring and autumn and (ii) compared the abilities of three modeling approaches to predict migratory movements between seasonal ranges of the 15 populations. Trade-offs between energy expenditure, food, and cover seemed to be the major driver of migration routes: steep south-facing snow-free slopes were selected while high elevation changes were avoided. This revealed the importance of favorable resources and an attempt to limit energy expenditures and perceived predation risk. Based on these findings, we provided efficient connectivity models to inform conservation of Alpine ibex and its habitats, and a framework for future research investigating connectivity in migratory species.

ecology↗

bioRxiv2023

Too disturbed or too hot: summer temperatures more than hikers disturbance affect circadian activity of females in northern chamois

Recreational activities often result in a spatial and/or temporal activity shift in wildlife. With the concurrent development of outdoor activities and increase in temperatures due to climate change, mountain species face increasing pressures in terms of managing their activity pattern to limit both risk exposure and thermal discomfort. Using more than 15 years of long-term GPS and activity sensor data, we investigated how female northern chamois, Rupicapra rupicapra rupicapra, adjust their summer circadian activity to spatiotemporal variation in both temperatures and hikers presence. Chamois behaviour was more affected by high temperatures than by hikers presence. During the hottest days, they shifted their activity peak earlier in the morning, were more active at night, less active during daytime and had longer morning and evening peaks compared to the coldest days. Global activity was only slightly different during the hottest than the coldest days. Conversely, hikers disturbance had weak effects on activity levels and on the timing of activity peaks. This is especially true for temporal disturbance (weekdays versus weekends and public holidays), possibly because most weekdays in summer fell during school holidays. During the hottest conditions, the morning activity peak was shorter and the evening peak longer in females living in the most exposed areas compared to females living in the least exposed areas. One possible explanation for the overall low effect of hikers disturbance may be that behavioural changes buffering animals from high temperatures and hikers presence (e.g. moving away from trails) allow them to just marginally modify their activity pattern. In the context of ongoing socioenvironmental changes, it is critical to conserve habitats providing thermal refuges against summer heat and protection from disturbance to mitigate potential detrimental consequences.

animal behavior and cognition↗

bioRxiv2022

Cellulosic copper nanoparticles and a hydrogen peroxide-based disinfectant protect Vero E6 cells against infection by viral pseudotyped particles expressing SARS-CoV-2, SARS-CoV or MERS-CoV Spike protein.

Severe acute respiratory syndrome (SARS) is a viral respiratory infection caused by human coronaviruses (HuCoV) that include SARS-CoV-2, SARS-CoV, and Middle East respiratory syndrome coronavirus (MERS-CoV). Although their primary mode of transmission is through contaminated respiratory droplets from infected carriers, the deposition of expelled virus particles onto surface and fomites could contribute to viral transmission. Here, we use replication-deficient murine leukemia virus (MLV) pseudoviral particles expressing SARS-CoV-2, SARS-CoV, or MERS-CoV Spike (S) protein on their surface. These surrogates of native coronavirus counterparts serve as a model to analyze the S-mediated entry into target cells. Carboxymethyl cellulose (CMC) nanofibers that are combined with copper (Cu) exhibit strong antimicrobial properties. S-pseudovirions that are exposed to CMC-Cu nanoparticles (30 s) display a dramatic reduction in their ability to infect target Vero E6 cells, with [~]97% less infectivity as compared to untreated pseudovirions. In contrast, addition of the Cu chelator tetrathiomolybdate protects S- pseudovirions from CMC-Cu-mediated inactivation. When S-pseudovirions were treated with a hydrogen peroxide-based disinfectant (denoted SaberTM) used at 1:16 dilution, their infectivity was dramatically reduced by [~]98%. However, the combined use of SaberTM and CMC-Cu is the most effective approach to restrict infectivity of SARS-CoV-2-S, SARS-CoV-S, and MERS-CoV-S pseudovirions in Vero E6 cell assays. Together, these results show that cellulosic Cu nanoparticles enhance the effectiveness of diluted SaberTM sanitizer, setting up an improved strategy to lower the risk of surface- and fomite-mediated transmission of enveloped respiratory viruses.

microbiology↗

bioRxiv2020

Path tortuosity changes the transport cost paradigm in terrestrial animals

Animal movement paths are variously tortuous, with high turn rates predicted to be energetically costly, especially at high speeds. Animals travel most efficiently at the speed that gives the lowest cost of transport (COT), a well-defined point for movement in fluid media. However, theoretically, land animals should travel at their maximum speed to minimize COT, which they do not, instead travelling at walking pace. We measured oxygen consumption in humans to demonstrate that the energetic costs of turning increase disproportionately with both speed and angular velocity. This resulted in the minimum COT speed occurring at very low speeds, which reduced with increased path tortuosity. Data on turn rates from six free-ranging terrestrial species underpinned this because all individuals turned faster at the slowest speeds across the full speed range. The optimum movement speed for minimum COT in land animals thus depends on the environment and behavior since both affect track tortuosity.

ecology↗

bioRxiv2020

Trends and gaps in the use of citizen science derived data as input for species distribution models: a quantitative review

Citizen science (CS) currently refers to some level of volunteer participation in any discipline of scientific research. Over the last two decades, nature-based CS has flourished due to innovative technology, novel devices, and widespread digital platforms used to collect and classify species occurrence data. For scientists, CS offers a low-cost approach of collecting species occurrence information at large spatial scales that otherwise would be prohibitively expensive. We examined the trends and gaps linked to the use of CS as a source of data for species distribution models (SDMs), in order to propose guidelines and highlight solutions. We conducted a quantitative literature review of 224 peer-reviewed articles to measure how the representation of different taxa, regions, and data types have changed in SDM publications since the 2010s. Our review shows that the number of papers using CS for SDMs has increased at approximately double the rate of the overall number of SDM papers. However, disparities in taxonomic and geographic coverage remain in studies using CS. Western Europe and North America were the regions with the most coverage (71.2%). Papers on birds (51.2%) and mammals (26.2%) outnumbered other taxa. Among invertebrates, flying insects including Lepidoptera and Odonata received the most attention. Compared to studies on animal taxa, papers on plants using CS data remain rare. Although the aims and scope of SDM papers are diverse, conservation remained the central theme of SDM using CS data. We present examples of the use of CS and highlight recommendations to motivate further research, such as combining multiple data sources and promoting local and traditional knowledge. We hope our findings will strengthen citizen-researchers partnerships to better inform SDMs, especially for less-studied taxa and regions. Researchers stand to benefit from the large quantity of data available from CS sources to improve global predictions of species distributions.

ecology↗