French Foundation for Biodiversity Research

ABSTRACTAnticipating ecosystem responses to global change requires identifying the isolated and combined effects of environmental disturbance across both space and time. Examining the coordinated responses of ecosystems has recently emerged as a powerful approach to advance this understanding. We conducted two complementary experiments to identify whether, and if so how, warming temperatures, nutrient enrichment, predator overexploitation (i.e., reduced apex predator abundance) and their combination drive coordinated responses of freshwater ecosystems by evaluating the dynamics of synchrony between control and disturbed mesocosms using high‐frequency dissolved oxygen saturation measurements, an integrative parameter of the metabolic balance of ecosystems. Nutrient enrichment desynchronized the oxygen dynamics and their component cycles between treatments, likely arising from elevated primary production. Warming and overexploitation tended to desynchronize oxygen cycles from the control, particularly at short time scales. Nutrient enrichment combined with warming dampened desynchronization between control (ambient) and treatment mesocosms, whereas desynchronization was enhanced when simultaneously subject to predator overexploitation. As one of the first experimental demonstrations of global change impacts on ecosystem synchrony, this study highlights the need—and opens new avenues—to detect alterations in ecosystem functioning across previously unexplored spatial and temporal scales.

ABSTRACTContextThe ongoing biodiversity crisis presents a complex challenge for ecological science. Despite a consensus on general biodiversity decline, identifying clear trends remains difficult due to variability in data, methodologies and scales of analysis.IdeasTo enhance our understanding of ongoing biodiversity changes and address discrepancies in biodiversity trend detection, we propose integrating macroecological theory with temporal and trait‐based perspectives. First, analysing temporal changes in diversity scaling relationships, such as species accumulation curves or distance decay, can reconcile and synthesise conflicting observations of biodiversity change, enabling quantification of diversity shifts from local to regional spatial scales. Second, diversity patterns across scales are linked to three proximate components: abundance, evenness and spatial aggregation of species. Investigating temporal changes in these components provides deeper insights into how human activities directly influence biodiversity trends. Third, incorporating species traits into the analysis of these macroecological patterns improves our understanding of human impacts on biodiversity by elucidating the links between species characteristics and their responses to environmental changes.Case StudyWe illustrate this integration in a case study of forest and farmland birds in France, highlighting how studying diversity changes across scales, and decomposing temporal change in different components can help to elucidate the mechanisms driving diversity change.ConclusionsWe discuss the limitations and challenges of this integrative approach and highlight how it offers a comprehensive framework for understanding the drivers of biodiversity change across scales. This framework facilitates a more nuanced understanding of how human activities impact biodiversity, ultimately paving the way for more informed actions to mitigate biodiversity loss across spatial and temporal scales.

Abstract Which animals do people fear most, and why? Exploring animal fears in humans is crucial for understanding reactions in the face of danger, addressing both innate and learned determinants. Because of the central role they are thought to have played in primate evolution, most studies have focused on the fear of snakes. Other studies that have looked at a wider range of animals have either focused on a limited number of species and/or sampled participants from a narrow range of geographical locations. To overcome these shortcomings, we developed an immersive online survey based on animal images matches, during which participants had to choose the animal they feared most. With responses from 17,353 participants from all continents, we were able to rank 184 species (mammals, reptiles, birds, arthropods and amphibians) on a fear scale. Our results showed that images of dangerous animals elicited frequent and rapid fear responses. However, danger alone was not sufficient to explain fear, as harmless animals also reached high fear scores. Fear responses varied with participants' age, geographical region of residence and level of declared biophobia. The discrepancy between actual levels of danger and declared fears in humans may be due to social transmission and increasing disconnection from natural environments. This study highlights the need to consider a wide range of animal species to identify and understand people's fear of certain species, integrating the complex relationship between ecological danger and socio‐cultural influences. Read the free Plain Language Summary for this article on the Journal blog.

Survival and cause-specific mortality rates are vital for evidence-based population forecasting and conservation, particularly for large carnivores, whose populations are often vulnerable to human-caused mortalities. It is therefore important to know the relationship between anthropogenic and natural mortality causes to evaluate whether they are additive or compensatory. Further, the relation between survival and environmental covariates could reveal whether specific landscape characteristics influence demographic performance. We used telemetry data on 681 Eurasian lynx (Lynx lynx), a model apex predator with large spatial requirements, that were tracked across their European distribution. Through time-to-event analyses, we sought to determine the variables associated with differences in their survival. Illegal killing was the main cause of mortality (33.8%), and mortality rates were similar in protected and hunted populations (8.6% and 7.0% per year, respectively). Survival varied greatly across populations (70-95% per year). Across all study sites, higher hunting and anthropogenic mortality rates were partially compensated by lower rates of other mortality causes but not by natural mortality alone. Variation in survival depended on sex (female survival was 1.5 times greater than male survival) and seasonality (highest risk during hunting season and winter), and lower survival rates were correlated with higher human modification of landscapes at both coarse (home range composition) and fine (habitat use within home range) scales. Some variation in survival was driven by unobserved factors, which, given the high rates of human-caused mortalities, including illegal killing, are of foremost concern. Due to the low natural mortality rates in protected and hunted populations, we conclude that anthropogenic causes of mortality are likely close to additive, such that maintaining or increasing refuge habitat with little human disturbance is critical to lynx conservation.

Abstract Planktonic Foraminifera have been collected from the water column with different plankton sampling devices equipped with nets of various mesh sizes, which impedes direct comparison of observed quantifications. Here, we use data on the community size structure of planktonic Foraminifera to assess the impact of mesh size on the measured abundance (ind m−3) of planktonic Foraminifera. We use data from the FORCIS database (Chaabane et al., 2023, Scientific Data 10: 354) on the global ocean at different sampling depths over the past century. We find a global cumulative increase in abundance with size, which is best described using a Michaelis–Menten function. This function yields multiplication factors by which one size fraction can be normalized to any other size fraction equal to or larger than 100 μm. The resulting size normalization model is calibrated over a range of different depth intervals, and validated with an independent dataset from various depth ranges. The comparison to Berger's (1969, Deep. Res. Oceanogr. Abstr. 16: 1–24) equivalent catch approach shows a significant increase in the predictive skill of the model. The new size normalization scheme enables comparison of Foraminifera abundance data sampled with plankton nets of different mesh sizes, such as compiled in the FORCIS database. The correction methodology may be effectively employed for various other plankton groups such as diatoms and dinoflagellates.

The Atlantic coast of South America supports many Nearctic shorebirds during their non-breeding season where they use a network of stop-over and wintering sites. To quantify the importance of French Guiana among those sites, we surveyed and resighted banded birds in the Kourou River estuary during two periods: 1989–1997 and 2005–2008. Twenty species were recorded, among which 15 were observed every year, during migration and/or boreal wintering. The most abundant species was Semipalmated Sandpiper (Calidris pusilla), accounting for 57% of all observations. In most Nearctic shorebird species, we observed dramatic changes in numbers and phenology between both survey periods. In the 1990s, the Kourou River estuary was mainly a post-breeding stop-over site; in the common shorebird species the largest numbers were observed in September and October. In the 2000s, only few species still occurred in significant post-breeding numbers, and migration peaks occured later for some of them. Observations of 304 banded individuals of five shorebird species indicated that some staging birds stopped in southern Canada and over-wintered in Brazil or Argentina. Many of our resighted birds stopped over in Delaware Bay in spring. Our results indicate the importance of French Guiana as a fall stop-over for Nearctic shorebirds using Western Atlantic Flyway.

Abstract Connectivity shapes species distribution across fragmented landscapes. Assessing landscape resistance to dispersal is challenging because dispersal events are rare and difficult to detect especially for elusive species. To address these issues, spatial occupancy models have been developed to integrate the resistance surface concept of landscape ecology and model patch occupancy dynamics through colonization and extinction while accounting for imperfect species detection. However, the most recent approach is based on least-cost path distances which assume that individuals disperse along the optimal route. Here, we develop a new spatial occupancy model that incorporates commute distances derived from circuit theory to model dispersal across sites. Our approach allows for explicit estimation of landscape connectivity and direct measure of uncertainty from detection/non-detection data. To illustrate our approach, we study the recolonisation of two carnivores in France, and quantify the degree to which rivers facilitate Eurasian otter (Lutra lutra) dispersal and highways impede Eurasian lynx (Lynx lynx) recolonisation. Overall, spatial occupancy models provide a flexible framework to acccommodate any distance metric designed to align with species dispersal ecology.Open Research StatementData and code used in this research are available on Zenodo athttps://zenodo.org/record/8376577

Habitat loss and degradation due to global agriculture land use is a major threat to biodiversity. Identifying agricultural management practices that mitigate these impacts is urgently needed. Thousands of experiments have been conducted worldwide in the last decades to compare the impacts of various agricultural management practices on biodiversity. The magnitudes of difference in biodiversity responses between pairs of agricultural practices, i.e. effect sizes, have now been synthesised in a growing number of meta-analyses. Yet, each meta-analysis generally focuses on a specific type of farming practice and on specific taxonomic groups, or a single region. Meta-analyses could furthermore yield different or sometimes opposite results for the similar research questions. Gathering all the effect sizes in one single dataset helps to critically assess and weigh the available evidence across all studied practices, taxonomic groups and geographical areas, and provide stakeholders a solid base to better inform their decisions. Here, we present a comprehensive dataset of 200 published meta-analyses gathering 1885 effect sizes based on more than 14 000 primary studies. We detail the effect of 8 main individual field practices (e.g. pest and disease management, amendment and fertilisation), 3 agricultural systems (e.g. organic farming, conservation agriculture) and 2 landscape level interventions (i.e. landscape complexity, land-use change). Our dataset covers numerous taxonomic groups over 14 phyla, including animals (e.g. birds, insects), microorganisms (e.g. fungi, bacteria), plants (e.g. trees, weeds). The dataset presented provides a resource to support decision-makers, farmers, and conservation ecologists alike for managing agricultural land for biodiversity.

ABSTRACT Considered as a transitional object, the comforting power of the teddy bear has often been asserted in many past studies without knowing its underlying determinants. Through a participatory study conducted during the European Researchers’ Night, this study aims to identify characteristics of teddy bears that influence their comforting power, including visual, olfactory and kinesthetic properties. We also tested the effect of ownership on comforting power. Our study revealed that the emotional bond shared with a teddy bear is a predominant factor. However, we identified characteristics that play a significant role in the perception of comfort, which lies in a combination of visual, olfactory, and especially kinesthetic characteristics. Through these results, our study identifies the determinants spontaneously taken into account in the attribution of teddy bears’ capacity to provide comfort. These results were independent of participants’ age, reminiscent of the teddy bear’s ability to provide comfort at all stages of life.