Find research datasets worth reusing

A Great Escape: resource availability and density-dependence shape population dynamics along trailing range edges

Populations along geographical range limits are often exposed to unsuitable climate and low resource availability relative to core populations. As such, there has been a renewed focus on understanding the factors that determine range limits to better predict how species will respond to global change. Using recent theory on range limits and classical understanding of density dependence, we evaluated the influence of resource availability on the snowshoe hare Lepus americanus along its trailing range edge. We estimated variation in population density, habitat use, survival, and parasite loads to test the Great Escape Hypothesis (GEH), i.e. that density dependence determines, in part, a species' persistence along trailing edges. We found that variability in resource availability affected density and population fluctuations and led to trade-offs in survival for snowshoe hare populations in the northeastern USA. Hares living in resource-limited environments had lower and less variable population density, yet higher survival and lower parasitism compared to populations living in resource-rich environments. We suggest that density-dependent dynamics, elicited by resource availability, provide hares a unique survival advantage and partly explain persistence along their trailing edge. We hypothesize that this low-density escape from predation and parasitism occurs for other prey species along trailing edges, but the extent to which it occurs is likely conditional on the quality of matrix habitat. Our work indicates that biotic factors play an important role in shaping species' trailing edges and more detailed examination of non-climatic factors is warranted to better inform conservation and management decisions.

Geography, environment, and colonization history interact with morph type to shape genomic variation in an Arctic fish

Polymorphic species are useful models for investigating the evolutionary processes driving diversification. Such processes include colonization history as well as contemporary selection, gene flow, and genetic drift, which can vary between intraspecific morphs as a function of their distinct life histories. The interactive and relative influence of such evolutionary processes on morph differentiation critically informs morph-specific management decisions and our understanding of incipient speciation. We therefore investigated how geographic distance, environmental conditions, and colonization history interacted with morph migratory capacity in the highly polymorphic fish species, Arctic Charr (Salvelinus alpinus). Using an 87k SNP chip we genetically characterized recently evolved anadromous, resident, and landlocked charr collected from 45 locations across a secondary contact zone of three charr glacial lineages in eastern Canada. A strong pattern of isolation by distance across all populations suggested geographic distance principally shaped genetic structure. Landlocked populations had lower genetic diversities and higher genetic differentiation than anadromous populations. However, genetic diversity was generally temporally stable in landlocked populations in comparison to recent decreases in anadromous populations. Genetic diversity positively correlated with latitude, potentially indicating southern anadromous populations' vulnerability to climate change and greater introgression between the Arctic and Atlantic glacial lineages in northern Labrador. Local adaptation was suggested by the observation of several environmental variables strongly associating with functionally relevant outlier genes including a region on chromosome AC21 potentially associated with anadromy. Our results demonstrate that gene flow, colonization history, and local adaptation uniquely interact to influence the genetic variation and evolutionary trajectory of populations.

opencc-by-4.0Jun 2023View details →

Parcel2D Real - A real-world image dataset of cuboid-shaped parcels with 2D and 3D annotations

Real-world dataset of ~400 images of cuboid-shaped parcels with full 2D and 3D annotations in the <a href="https://cocodataset.org/#format-data">COCO format</a>. Relevant computer vision tasks: <ul> <li>bounding box detection</li> <li>instance segmentation</li> <li>keypoint estimation</li> <li>3D bounding box estimation</li> <li>3D voxel reconstruction (.binvox files)</li> <li>3D reconstruction (.obj files)</li> </ul> For details, see our <a href="https://ieeexplore.ieee.org/abstract/document/10069342">paper</a> and <a href="https://a-nau.github.io/parcel2d/">project page</a>.   If you use this resource for scientific research, please consider citing <pre><code>@inproceedings{naumannScrapeCutPasteLearn2022, title = {Scrape, Cut, Paste and Learn: Automated Dataset Generation Applied to Parcel Logistics}, author = {Naumann, Alexander and Hertlein, Felix and Zhou, Benchun and Dörr, Laura and Furmans, Kai}, booktitle = {{{IEEE Conference}} on {{Machine Learning}} and Applications ({{ICMLA}})}, date = 2022 }</code></pre>

Data from: Subgenome dominance shapes novel gene evolution in the decaploid pitcher plant Nepenthes gracilis

Subgenome dominance after whole-genome duplication generates distinction in gene number and expression at the level of chromosome sets, but it remains unclear how this process may be involved in evolutionary novelty. Here, we generated a chromosome-scale genome assembly of the Asian pitcher plant Nepenthes gracilis to analyze how its novel traits (dioecy and carnivorous pitcher leaves) are linked to genomic evolution. We found a decaploidal karyotype with a complete set of syntenic chromosomes (2n=10x=80) yet with a clear indication of subgenome dominance and highly diploidized gene contents. The male-linked and pericentromerically located region on the putative sex chromosome was identified in a recessive subgenome and harbored three transcription factors involved in flower and pollen development, including a likely neofunctionalized LEAFY duplicate. Transcriptomic and syntenic analyses suggested that the paleopolyploidization events seeded genes that subsequently formed tandem clusters in recessive subgenomes with the specific expression in the digestive zone, where specialized cells digest prey and absorb derived nutrients. Novel gene evolution in recessive subgenomes is likely to be prevalent there because duplicates were enriched with Nepenthes-specific genes with tissue-specific expression, including those expressed in pitcher-specific tissues. Thus, subgenome dominance likely contributed to evolutionary novelty by allowing recessive subgenomes to serve as a preferred host of novel tissue-specific duplicates. Our results provide insight into how polyploids, which may frequently be evolutionary dead-ends, have given rise to novel traits in exceptionally thriving high-ploidy lineages.

Astyanax cavefish body shape coordinates from: Phylogeographic relationships and morphological evolution between cave and surface Astyanax mexicanus populations (De Fillipi 1853) (Actinopterygii, Characidae)

The Astyanax mexicanus complex includes two different morphs, a surface and a cave-adapted ecotype, found at three mountain ranges in Northeastern Mexico: Sierra de El Abra, Sierra de Guatemala, and Sierra de la Colmena (Micos). Since their discovery, multiple studies have attempted to characterize the timing and the number of events that gave rise to the evolution of these cave-adapted ecotypes. Here, using RAD-seq and genome-wide sequencing, we assessed the phylogenetic relationships, genetic structure, and gene flow events between the cave and surface Astyanax mexicanus populations, to estimate the time and mode of evolution of the cave-adapted ecotypes. We also evaluated the body shape evolution across different cave lineages using geometric morphometrics to examine the role of phylogenetic signal vs. environmental pressures. We found strong evidence of parallel evolution of cave-adapted ecotypes derived from two separate lineages of surface fish and hypothesize that there may be up to four independent invasions of caves from surface fish. Moreover, a strong congruence between the genetic structure and geographic distribution was observed across the cave populations, with the Sierra de Guatemala the region exhibiting most genetic drift among the cave populations analyzed. Interestingly, we found no evidence of phylogenetic signal in body shape evolution, but we found support for parallel evolution in body shape across independent cave lineages, with cavefish from the Sierra de El Abra reflecting the most divergent morphology relative to surface and other cavefish populations.

The relative role of climate and biotic interactions in shaping the range limits of a neotropical orchid

Aim The center-periphery hypothesis (CPH) explains the decline of species abundance towards range limits and how this is driven by increasing ecological marginality. So far, most studies testing the CPH have focused on abiotic factors contributing to marginality, while the role of biotic interactions in limiting species distribution has been neglected. Here, we investigate both drivers' roles in potentially restricting an orchid's range along a broad environmental gradient. Location Brazilian Atlantic Forest and Pampas biomes (south and southeastern Brazil) Taxa Sand dune orchid Epidendrum fulgens (Orchidaceae). Methods We integrated empirical data on geographical distribution, pollinator richness, and niche models to investigate whether range limits match predicted niche limits and whether habitat suitability declines towards low- and high-latitude species ranges. In addition, we used genetic-derived metrics to test whether populations at range edges are indeed small and isolated, as predicted by the CPH. Results Our results show that ecological conditions become more marginal towards the edges of the E. fulgens range, with an abrupt variation in climate. We also found that the climate has primarily shaped the species' high-latitude limit, while pollinator richness increases habitat suitability of E. fulgens in the low-latitude edge range, likely explaining the species' persistence. Genetic diversity within E. fulgens populations decreases while genetic differentiation increases towards both margins, although with a more consistent pattern for the low-latitudinal component. Main conclusions Our results corroborate most of the predictions associated with CPH, highlighting distinct factors limiting geographical distribution at the opposite margins of this latitudinal and narrowly-distributed species. This study is a first step towards understanding the relative role of climate and biotic interactions in shaping the range limits of coastal species, with significant potential for informing conservation practices.

Fruit-shape data of 574 Chinese white olives

We digitized the side profiles of 574 fruits of Canarium album (Lour.) DC., and used an explicit re-expression of Preston's equation (referred to as EPE hereinafter) to fit the planar coordinates of each fruit profile. By using the estimated parameters, we calculated the volume and surface area of each fruit. The black_white.zip file saves the black and white .bmp images at 600 dpi for the 574 fruit profiles. The edge_data.zip file includes the planar coordinates of each of the 574 fruits, and the EPE_results.csv file includes the estimated parameters and goodness-of-fit of the EPE, and the fruit surface area and volume calculated by the surface area and volume formulas of the solid of revolution based on the EPE for each fruit. In addition, the EPE_results.csv file also provided the measured volumes of 574 fruits using graduated cylinders.

Data from: Virus community structuring is shaped by habitat heterogeneity and resource utilisation strategies

After decades of disconcerted research, we still recognise large gaps in the understanding of mechanisms that govern disease dynamics in complex biological communities. To determine how spatial structuring of plant communities caused by anthropic disturbance affects resource utilisation traits of viruses, we combine high-throughput, network, and metacommunity approaches. We find that the disturbance gradient corresponded to network modules and habitat specificity exhibited by a majority of viruses. Communities were connected through key hub species of either generalist viruses or high potential host reservoirs. Spatial dependencies were evident in regression models of species richness and correlations between metacommunity structure and both host range and transmission mode at finer spatial resolutions. We propose that virus community assembly is influenced by variation in niche opportunities. Distinctions in virus community composition caused by resource compartmentalisation can be used to track ecological traits important in forecasting transmission risk.

Changes in nitrogen and phosphorus availability driven by secondary succession in temperate forests shape soil fungal communities and function

Soil fungal community plays an important role in forest ecosystems, and forest secondary succession is a crucial driver of soil fungal community. However, the driving factors of fungal community and function during temperate forest succession and their potential impact on succession processes are poorly understood. In this study, we investigated the dynamics of the soil fungal community in three temperate forest secondary successional stages (shrublands, coniferous forests, and deciduous broadleaf forests) using high-throughput DNA sequencing coupled with functional prediction via the FUNGuild database. We found that fungal community richness, α-diversity, and evenness decreased significantly during the succession process. Soil available phosphorus and nitrate nitrogen decreased significantly after initial succession occurred, and redundancy analysis showed that both were significant predictors of soil fungal community structure. Among functional groups, fungal saprotrophs as well as pathotrophs represented by plant pathogens were significantly enriched in the early-successional stage, while fungal symbiotrophs represented by ectomycorrhiza were significantly increased in the late-successional stage. The abundance of both saprotroph and pathotroph fungal guilds was positively correlated with soil nitrate nitrogen and available phosphorus content. Ectomycorrhizal fungi were negatively correlated with nitrate nitrogen and available phosphorus content and positively correlated with ammonium nitrogen content. These results indicated that the dynamics of fungal community and function reflected the changes in nitrogen and phosphorus availability caused by the secondary succession of temperate forests. The fungal plant pathogen accumulated in the early-successional stage and ectomycorrhizal fungi accumulated in the late-successional stage may have a potential role in promoting forest succession. These findings contribute to a better understanding of the response of soil fungal communities to the secondary forest succession process and highlight the importance of fungal communities during temperate forest succession.

opencc-by-3.0Jul 2023View details →

Research compendium for 'Hussain et al. (2023) A pan-European dataset revealing variability in lithic technology, toolkits, and artefact shapes ~15-11 kya'

Research compendium for 'A pan-European dataset revealing variability in lithic technology, toolkits, and artefact shapes ~15-11 kya' Compendium DOI: <a href="https://doi.org/10.5281/zenodo.7940337">https://doi.org/10.5281/zenodo.7940337</a> The files at the URL above will generate the results as found in the publication. The files hosted at <a href="https://github.com/yesdavid/1511NAC_Dataset">https://github.com/yesdavid/1511NAC_Dataset</a> are the development versions and may have changed since the paper was published. Maintainer of this repository: David N. Matzig (<a href="mailto:david.matzig@cas.au.dk">david.matzig@cas.au.dk</a>; <a href="http://orcid.org/0000-0001-7349-5401">http://orcid.org/0000-0001-7349-5401</a>) Published in: Shumon T. Hussain, Felix Riede, David N. Matzig, Miguel Biard, Philippe Crombé, Federica Fontana, Daniel Groß, Thomas Hess, Mathieu Langlais, Javier Fernández-Lopéz de Pablo, Ludovic Mevel, William Mills, Martin Moník, Nicolas Naudinot, Caroline Posch, Tomas Rimkus, Damian Stefański, Hans Vandendriessche. A pan-European dataset revealing variability in lithic technology, toolkits, and artefact shapes ~15-11 kya. Sci Data 10, 593 (2023). <a href="https://doi.org/10.1038/s41597-023-02500-9">https://doi.org/10.1038/s41597-023-02500-9</a>. Abstract: Comparative macro-archaeological investigations of the human deep past rely on the availability of unified, quality-checked datasets integrating different layers of observation. Information on the durable and ubiquitous record of Paleolithic stone artefacts and technological choices are especially pertinent to this endeavour. We here present a large expert-sourced collaborative dataset for the study of stone tool technology and artefact shape evolution across Europe between ~15.000 and 11.000 years before present. The dataset contains a compendium of key sites from the study period, and data on lithic technology and toolkit composition at the level of the cultural taxa represented by those sites. The dataset further encompasses 2D shapes of selected lithic artefact groups (armatures, endscrapers, and borers) shared between cultural taxa. These data offer novel possibilities to explore within- and between-region patterns of material culture change to reveal scale-dependent processes of long-term technological evolution in mobile hunter-gatherer societies at the end of the Pleistocene. Our dataset facilitates state-of-the-art quantitative analyses and showcases the benefits of collaborative data collation and synthesis. Keywords: Europe; Pleistocene-Holocene transition; Late Glacial archaeology; lithic technology; comparison; macro-archaeology; taxonomy; cultural evolution; digital methods; computational morphometrics; collaborative research; open science Overview of contents and how to reproduce: This repository contains data (<code>1_data</code>) and code (<code>2_scripts</code>) for the paper, as well as the <code>1511NAC_Dataset</code> folder. The <code>1511NAC_Dataset</code> folder contains all relevant data for the readers to start their own analyses using the dataset. After downloading the complete repository, the results can be reproduced using <code>1511NAC_dataset.Rproj</code> and the existing folder structure. The required packages and their versions which have been used in this study are listed below and in the <code>DESCRIPTION</code>-file. All analyses and visualisations presented in this paper were prepared in R 4.2.2 under Ubuntu 18.04.5 LTS (64-bit). Required R-packages and their versions: <code>data.table</code> (>= 1.14.8), <code>dplyr</code> (>= 1.1.2), <code>forcats</code> (>= 1.0.0), <code>ggforce</code> (>= 0.4.1), <code>ggplot2</code> (>= 3.4.2), <code>ggpointgrid</code> (>= 1.2.0), <code>ggridges</code> (>= 0.5.4), <code>magrittr</code> (>= 2.0.3), <code>Momocs</code> (>= 1.4.0), <code>outlineR</code> (>= 0.1.0), <code>raster</code> (>= 3.6-20), <code>readr</code> (>= 2.1.4), <code>remotes</code> (>= 2.4.2), <code>rgeos</code> (>= 0.6-2), <code>rworldmap</code> (>= 1.3-6), <code>sp</code> (>= 1.6-0). Licenses: Code: MIT <a href="http://opensource.org/licenses/MIT">http://opensource.org/licenses/MIT</a>, copyright holder: David Nicolas Matzig (2023). Data and intellectual work: Creative Commons Attribution 4.0 International License (<a href="http://creativecommons.org/licenses/by/4.0/">http://creativecommons.org/licenses/by/4.0/</a>), copyright holder: the authors (2023).

opencc-by-4.0Jul 2023View details →

Replication package for: "Corrupted by Algorithms? How AI-generated and Human-written Advice Shape (Dis)honesty"

Package to the following paper: Leib, M; Köbis, N; Rilke, R M; Hagens, M; Irlenbusch, B (2023)  Corrupted by Algorithms? How AI-generated and Human-written Advice Shape (Dis)honesty

Data from: The nightscape of the Arctic winter shapes the diving behavior of a pelagic predator

Predator-prey interactions in marine ecosystems are dynamically structured by light, which is exemplified by diel vertical migrations of low-trophic level organisms. At high latitudes, the long winter nights provide foraging opportunities for marine predators targeting vertically migrating prey closer to the surface at night while minimizing energy expenditure, but there is limited documentation of such diel patterns under extreme light regimes. To address this knowledge gap, we recorded the diving behavior of 17 harbour porpoises just south of the Arctic circle in West Greenland, from summer to winter. Unlike classical diel vertical migration, the porpoises dove three times deeper at night and the frequency of deep dives (>100 m) increased tenfold as they entered the darkest months. The daily mean depth was negatively correlated with daylength, confirming this reverse diel migration and suggesting an increased activity—presumably to target prey at greater depths—when approaching the polar night. Our findings illustrate a light-mediated strategy in which harbour porpoises would maximize energy gain during long periods of darkness while minimizing energy expenditure by accessing vertically migrating prey, which are otherwise inaccessible in deep waters. Extreme light regimes observed at high latitudes are therefore critical in structuring pelagic communities and food webs.

opencc-by-4.0Sep 2022View details →

Homology judgements of pre-Darwinian naturalists explained by general human shape matching abilities

Dataset relative to the following publication: Stegmann, U., & Schmidt, F. (2023). Homology judgements of pre-evolutionary naturalists explained by general human shape matching abilities. Scientific Reports, 13, 12269. Each experiment folder contains the data relative to one experiment, together with a text file with comments.

opencc-by-4.0Jul 2023View details →

Supplementary data to "What are the effects of temperature on plasticity, shape symmetry and seasonal variation in freshwater benthic green microalga Micrasterias thomasiana?"

The supplementary data consist of the files including the landmark coordinates of Micrasterias thomasiana semicells used for the analyses described in the manuscript submitted to Aquatic Ecology. The coordinates are presented in the TPS format.

Directional and stabilizing selection shaped morphological, reproductive, and physiological traits of the invader Solidago canadensis

Trait evolution in invasive plant species is important because it can impact demographic parameters key to invasion success. Invasive plant species often show phenotypic clines along geographic and climatic gradients. However, the relative contributions of natural selection and neutral evolutionary processes to phenotypic trait variation among populations of invasive plants remains unclear. A common method to assess whether a trait has been shaped by natural selection or neutral evolutionary processes is to compare the geographical pattern for the trait of interest to the divergence in neutral genetic loci (i.e., QST-FST comparisons). A redundancy analysis (RDA) can facilitate identification of putative agents of natural selection on the trait. Here, we employed both a QST-FST comparisons approach and RDA to infer whether natural selection shaped traits of invasive populations of S. canadensis in China and identify the potential environmental drivers of natural selection. We addressed two questions: (1) Does natural selection drive phenotypic trait variation among S. canadensis populations? (2) Do climatic, latitudinal, longitudinal, and altitudinal gradients drive patterns of genetic variation among S. canadensis populations? We found significant directional selection for several morphological and reproductive traits (i.e., QST >FST) and stabilizing selection for physiological traits (i.e., QST < FST). The RDA showed that stem biomass of S. canadensis was strongly positively correlated with longitude, while leaf width ratio and specific leaf area were significantly positively correlated with mean diurnal range. Stem biomass had a strong negative correlation with annual precipitation. Moreover, height of S. canadensis individuals was strongly positively correlated with altitude and precipitation of the wettest quarter. Precipitation seasonality that was associated with longitudinal shift in China likely selected for larger stem biomass in S. canadensis. Overall, these results suggest that longitudinal and altitudinal clines in climate exerted strong selection pressures that shaped phenotypic traits of S. canadensis.

Data from: Paleoenvironments shaped the exchange of terrestrial vertebrates across Wallace's Line

Faunal turnover in Indo-Australia across Wallace's Line is one of the most recognizable patterns in biogeography and has catalyzed debate about the role of evolutionary and geoclimatic history in biotic interchanges. Here, analysis of over 20,000 vertebrate species with a model of geoclimate and biological diversification shows that broad precipitation tolerance and dispersal ability were key for exchange across the deep-time precipitation gradient spanning the region. Sundanian (Southeast Asian) lineages evolved in a climate similar to the humid 'stepping stones' of Wallacea, facilitating colonization of the Sahulian (Australian) continental shelf. In contrast, Sahulian lineages predominantly evolved in drier conditions, hampering establishment in Sunda, and shaping faunal distinctiveness. We demonstrate how the history of adaptation to past environmental conditions shapes asymmetrical colonization and global biogeographic structure. Faunal turnover in Indo-Australia across Wallace's Line is one of the most recognizable patterns in biogeography and has catalyzed debate about the role of evolutionary and geoclimatic history in biotic interchanges. Here, analysis of over 20,000 vertebrate species with a model of geoclimate and biological diversification shows that broad precipitation tolerance and dispersal ability were key for exchange across the deep-time precipitation gradient spanning the region. Sundanian (Southeast Asian) lineages evolved in a climate similar to the humid 'stepping stones' of Wallacea, facilitating colonization of the Sahulian (Australian) continental shelf. In contrast, Sahulian lineages predominantly evolved in drier conditions, hampering establishment in Sunda, and shaping faunal distinctiveness. We demonstrate how the history of adaptation to past environmental conditions shapes asymmetrical colonization and global biogeographic structure.

Data from: Biofilms as self-shaping growing nematics

Active nematics are the nonequilibrium analog of passive liquid crystals in which anisotropic units consume free energy to drive emergent behavior. Similar to liquid crystal (LC) molecules in displays, ordering and dynamics in active nematics are sensitive to boundary conditions; however, unlike passive liquid crystals, active nematics, such as those composed of living matter, have the potential to regulate their boundaries through self-generated stresses. Here, using bacterial biofilms confined by a hydrogel as a model system, we show how a three-dimensional, living nematic can actively shape itself and its boundary in order to regulate its internal architecture through growth-induced stresses. We show that biofilms exhibit a sharp transition in shape from domes to lenses upon changing environmental stiffness or cell-substrate friction, which is explained by a theoretical model considering the competition between confinement and interfacial forces. The growth mode defines the progression of the boundary, which in turn determines the trajectories and spatial distribution of cell lineages. We further demonstrate that the evolving boundary defines the orientational ordering of cells and the emergence of topological defects in the interior of the biofilm. Our findings reveal novel self-organization phenomena in confined active matter and provide strategies for guiding the development of programmed microbial consortia with emergent material properties.

Functional identity of dominant species in a predator community prevails over functional diversity in shaping the top-down control of herbivores

<ol> <li>Decline in species richness as well as changes in community evenness or functional diversity have been hypothesized to jointly affect ecosystem functioning. However, disentangling the relative effects of these changes in community structure is hard as these different aspects often covary with species richness in real-world ecosystems. In this study, we investigated the individual and interactive effects of functional diversity and community evenness of predators on the level of control of herbivorous prey. </li> <li>Using a highly-replicated mesocosm experiment, we crossed three levels of functional diversity of arthropod predators with two levels of community evenness while controlling for the effect of species richness. Using this experimental setting, we hypothesized that the effect size of functional diversity of predators depends on community evenness. We expected a positive effect of functional diversity of predators on top-down control at a high level of community evenness while we thought that species identity and their associated traits should drive most of the effect on top-down control at a low level of community evenness. </li> <li>Our results did not provide any evidence for an interaction between functional diversity and community evenness nor any beneficial effect of increased functional diversity overall on predation rates of herbivorous prey. In addition, our results revealed that species and functional identity drives most of the effects of predator community composition on top-down control of their prey in our study system. Assemblages composed of active hunters with low handling time and no starvation ability tended to have the highest impacts on prey biomass.</li> <li>By indicating that top-down control of herbivorous prey by arthropod predators is mainly driven by species and functional identity and not by functional diversity, our study provides insights into the consequences of ongoing species loss on ecosystem functioning. Future research should now explore the predictability of trophic interactions based on functional traits of predator and herbivorous prey to anticipate the consequences of changes in species composition on ecosystem functioning.</li> </ol>

Zircon 2D shape and geochemistry

This data set accompanies the G-Cubed manuscript titled "Does Zircon Shape Retain Petrogenetic Information?". It presents individual zircon 2D shape measurements coupled with individual grain U and Th contents (where applicable) and sample whole-rock geochemistry.

Lake water chemistry and local adaptation shape NaCl toxicity in Daphnia ambigua

The increasing application of road deicing agents (e.g., NaCl) has caused widespread salinization of freshwater environments. Chronic exposure to toxic NaCl levels can impact freshwater biota at genome to ecosystem scales, yet the degree of harm caused by road salt pollution is likely to vary among habitats and populations. The background water chemistry may strongly impact NaCl toxicity, with greater harm occurring in ion-poor freshwater environments. In addition, populations exposed to salinization may evolve increased NaCl tolerance. We examined the potential for these two factors, genetics and environmental context, to interact in shaping NaCl toxicity in natural populations of the water flea Daphnia ambigua. We performed a reciprocal transplant toxicity trial using Daphnia clones from three lakes varying in ion availability. NaCl toxicity greatly increased in calcium-poor (1.7 mg/L) lake water compared with a high-calcium (7.2 mg/L) environment, especially for Daphnia from the high-calcium lake. Meanwhile, Daphnia from an ion-rich lake showed evidence of adaptation to NaCl exposure, especially in their natal lake water. Our findings that the lake water environment, adaptation to that environment, and adaptation to a contaminant of interest may interact to shape toxicity demonstrate the importance of considering environmental and genetic complexity in mitigating pollution impacts.