Biology subjects

Sandel, B.

Publications and source records attributed to Sandel, B..

4 recordsLinked to original sources

bioRxiv2022

The Universal Endurance Microbiome?

Billions of microbial cells sculpt the gut ecosystem, playing essential roles in human physiology. Since endurance athletes performance is often physiology-limited, understanding the composition and interactions within these athletes gut microbiomes could lead to improved performance. Previous studies describe differences in the relative abundance of bacterial taxa when comparing athletes versus controls or athletes before and after an endurance event, suggesting the existence of an "endurance microbiome". However, there are inconsistencies among studies in which taxa correlate with extended physical exertion. Although these studies employed similar barcoding methods, variation in downstream bioinformatic analyses makes it difficult to determine whether inconsistencies are due to methodological differences or biological factors. Herein, we created a metagenomic bioinformatics workflow reanalyzing four 16S rDNA sequence datasets reflecting endurance athletes gut microbiomes, looking at alpha diversity, changes in relative abundance of gut microbiome genera, changes in pairwise correlations between bacterial genera and compared bacterial association networks. There were no significant differences in alpha diversity between any of the four treatment group comparisons. For relative abundance, there were no consistent differences in all four datasets, and only two genera were significantly different in 50% of the datasets. Although many genera showed changes in pairwise correlations in endurance microbiome samples from individual datasets, none were consistent across datasets. Collectively, these results suggest that either there is no universal endurance microbiome, or that it remains elusive even after controlling for the bioinformatic workflow and statistical analyses. Using this data, a power analysis indicates that sample sizes 150- to 800-fold larger than these published studies would be necessary to detect a 10% difference in relative abundance. Furthermore, 10- to 20-fold more samples will be needed to control for the multitude of covariates (genetic, metabolic, dietary, environmental, and pharmacological factors) that mold the gut microbiome of athletes and non-athletes alike. Im going to work so that its a pure guts race at the end, and if it is, I am the only one who can win it. - Steve Prefontaine

microbiology↗

bioRxiv2019

Responses of global waterbird populations to climate change vary with latitude

While climate change continues to present a major threat to global biodiversity and ecosystems, most research on climate change impacts do not have the resolution to detect changes in species abundance and are often limited to temperate ecosystems. This limits our understanding of global responses in species abundance--a determinant of ecosystem function and services--to climate change including in the highly-biodiverse tropics. We address this knowledge gap by quantifying abundance responses to climate change in waterbirds, an indicator taxon of wetland biodiversity, at 6,822 sites between -55{degrees} and 64{degrees}. Using 1,303,651 count records since 1990 of 390 species, we show that with temperature increase, the abundance of species and populations decreased at lower latitudes, particularly in the tropics, but increased at higher latitudes. These contrasting responses to temperature increase according to latitude indicate potential global-scale poleward shifts of species abundance under climate change, providing empirical support for predictions by earlier studies. The negative responses to temperature increase in tropical species and populations are of conservation concern, as they are often also threatened by other anthropogenic factors. Our results suggest that existing biases in studies towards temperate regions could underestimate the impact of climate change on waterbirds and other species.

ecology↗

bioRxiv2019

Recent global changes have decoupled species richness from specialization patterns in North American birds

AimTheory suggests that increasing productivity and climate stability toward the tropics can explain the latitudinal richness gradient by favouring specialization. A positive relationship between species richness and specialization should thus emerge as a fundamental biogeographic pattern. However, land use and climate change disproportionally increase the local extirpation risk for specialists, potentially impacting this pattern. Here, we empirically quantify the richness-specialization prediction and test how 50 years of climate and land use change has affected the richness-specialization relationship.\n\nLocation\n\nUSA\n\nTime period\n\n1966-2015\n\nMajor taxa studied\n\nBirds\n\nMethodsWe used the North American breeding bird survey to quantify bird community richness and specialization to habitat and climate. We assess i) temporal change in the slope of the richness-specialization relationship, using a Generalized Mixed Model; ii) temporal change in spatial covariation of richness and specialization as driven by local environmental conditions, using Generalized Additive Models; and iii) land use, climate and topographic drivers of the spatio-temporal changes in the relationship, using a multivariate method.\n\nResultsWe found evidence for a positive richness-specialization relationship in bird communities. However, the slope of the relationship declined strongly over time. Richness spatially covaried with specialization following a unimodal pattern. The peak of the unimodal pattern shifted toward less specialized communities over time. These temporal changes were associated with precipitation change, decreasing temperature stability and land use.\n\nMain conclusionsRecent climate and land use changes induced two antagonist types of community responses. In human-dominated areas, the decoupling of richness and specialization drove a general biotic homogenization trend. In human-preserved areas under increasing climate harshness, specialization increased while richness decreased in a \"specialization\" trend. Our results offer new support for specialization as a key driver of macroecological diversity patterns, and show that global changes are erasing this fundamental macroecological pattern.\n\nBiosketchAnne Mimet is a postdoctoral researcher interested in the understanding of human impacts on biodiversity through land use and climate changes, at various spatio-temporal scales. She is interested in embracing the complexity of socio-ecological systems, and in the understanding of biodiversity trends in a human-dominated world in the context of the general theories of ecology.

ecology↗

bioRxiv2018

Wild Steps in a Semi-wild Setting? Habitat Selection and Behavior of European Bison reintroduced to an Anthropogenic Landscape

Recently, several wild or semi-wild herds of European bison have been reintroduced across Europe. It is essential for future successful bison reintroductions to know how the European bison use different habitats, which environmental parameters drive their habitat selection, and whether their habitat use and behavioural patterns in new reintroduction sites differ from habitats where European bison have been roaming freely for a long time.\n\nHere, we address these questions for a 40-ha enclosed site that has been inhabited by semi-free ranging European bison since 2012. The site, Vorup Meadows, is adjacent to the Guden[a] river in Denmark and consists of human-modified riparian meadows. During 2013 we monitored the behavioural pattern and spatial use of the 11 bison present and in parallel carried out floristic analyses to assess habitat structure and food quality in the enclosure. We tested habitat use and selection against environmental parameters such as habitat characteristics, plant community traits, topography, and management area (release area vs. meadow area) using linear regression and spatial models.\n\nThe bison herd had comparable diurnal activity patterns as observed in previous studies on free-roaming bison herds. Topography emerged as the main predictor of the frequency of occurrence in our spatial models, with high-lying drier areas being used more. Bison did not prefer open areas over areas with tree cover when accounting for habitat availability. However, they spent significantly more time in the release area, a former agricultural field with supplementary fodder, than expected from availability compared to the rest of the enclosure, a meadow with tree patches. We wish to increase awareness of possible long-term ethological effects of the release site and the management protocols accomplished here that might reduce the ecological impact by the bison in the target habitat, and thereby compromise or even oppose the conservation goals of the conservation efforts.

ecology↗