Linking human impacts to community processes in terrestrial and freshwater ecosystems

Agriculture's impact on water-energy balance varies across climates

Agriculture is a cornerstone of global food production, accounting for a substantial portion of water withdrawals worldwide. As the world's population grows, so does the demand for water in agriculture, leading to alterations in regional water-energy balances. We present an approach to identify the influence of agriculture on the water-energy balance using empirical data. We explore the departure from the Budyko curve for catchments with agricultural expansion and their associations with changes in the water-energy balance using a causal discovery algorithm. Analyzing data from 1,342 catchments across three Köppen-Geiger climate classes-temperate, snowy, and others-from 1980 to 2014, we show that temperate and snowy catchments, which account for over 90% of stations, exhibit distinct patterns. Cropland percentage (CL%) emerges as the dominant factor, explaining 47 and 37% of the variance in deviations from the Budyko curve in temperate and snowy catchments, respectively. In temperate catchments, CL% shows a strong negative correlation with precipitation-streamflow (P-Q) causal strength (Spearman [Formula: see text]), suggesting that cropland exacerbates precipitation-driven deviations. A moderate negative correlation with aridity-streamflow (AR-Q) causal strength ([Formula: see text]) indicates additional influences of cropland through aridity-driven interactions. In snowy catchments, CL% is similarly influential, with a positive correlation with P-Q causal strength ([Formula: see text]). However, the negative correlation with AR-Q causal strength ([Formula: see text]) underscores the role of aridity as a secondary driver. While vegetation and precipitation seasonality also contribute to the deviations, their impacts are comparatively lower. These findings underscore the need for inclusion of agricultural activities in changing water-energy balance to secure future water supplies.

Identifying Critical Land Use Thresholds for Biodiversity Conservation in China's Lake Ecosystems

Aquatic biodiversity loss, particularly in rapidly developing nations, continues to raise concerns, prompting urgent debates on reconciling economic growth with environmental preservation through land use planning. While spatial variations in aquatic communities along land use gradients are well-documented, precise ecological thresholds for land use impacts on freshwater lakes remain elusive, hindering sustainable development efforts. This study investigated six representative freshwater lakes in China between 2019 and 2020, all significantly impacted by anthropogenic activities. We utilized macroinvertebrate communities as bioindicators and employed four categories of aquatic ecological metrics─taxonomic diversity, functional diversity, pollution tolerance, and water quality─to assess their responses to local land use patterns. Macroinvertebrate community composition varied significantly among the studied lakes, with pollution-tolerant taxa predominating in highly urbanized and eutrophic systems. Notably, benthic communities exhibited greater sensitivity to urban land use (ecological thresholds: 2-10%) compared to agricultural land use (thresholds: 15-40%). The most pronounced responses were observed within 1-5 km of the lakeshore, with circular buffers yielding more significant effects than fan-shaped buffers, excluding water areas. A novel land use intensity indicator─the ratio of nonecological to ecological land (NEL/EL = area of nonecological land/area of ecological land)─proved effective in predicting ecological shifts. Smaller or heavily urbanized lakes showed marked changes at NEL/EL ratios between 0 and 0.6, while larger or river-connected lakes exhibited shifts at ratios exceeding 1.5. These findings underscore the profound ecological footprint of human activities on lake ecosystems with urban land cover emerging as the most deleterious factor.

Global Projection of Terrestrial Vertebrate Food Webs Under Future Climate and Land-Use Changes

Food webs represent an important nexus between biodiversity and ecosystem functioning, yet considering changes in food webs around the world has been limited by data availability. Previous studies have predicted food web collapses and coextinction, but changes in food web structure have been less investigated under climate warming and anthropogenic pressures on a global scale. We systematically amassed information about species' diets, traits, distributions, habitat use, and phylogenetics in the real world and used machine learning to predict changes in global meta-food webs of terrestrial vertebrates under climate and land-use changes. By year 2100, terrestrial vertebrate food webs are expected to decrease in web size by 32% and trophic links by 49%. Projections predict declines of over 25% in modularity, predator generality, and diversity of trophic groups. Increased species' dispersal could ameliorate these trends but indicate disproportionate vulnerability of regional food webs. Unlike many previous studies, this work combines extensive empirical data with advanced modeling techniques, providing a more detailed and spatially explicit prediction of how global food webs will respond to climate and land-use changes. Overall, our study predicts terrestrial vertebrate food webs will undergo drastic and spatially heterogeneous structural changes.

Reduced avoidance behaviour in Daphnia magna due to agrochemical-induced vulnerability

The continuous discharge of agrochemicals used in intensive agriculture contaminates aquatic systems, harming aquatic biota and their processes. Although mobile organisms can avoid continuous exposure by moving to less-affected habitats, their capacity can be altered by pollutant exposure. Populations with a previous disturbance history, which show a lower ability to respond to subsequent stressors, are defined as vulnerable. Therefore, this study investigated the so far unknown escape capacity of a vulnerable zooplankton population previously exposed to a contaminated environment. To this end, agrochemically driven vulnerability was induced in populations of Daphnia magna by exposure to sublethal concentrations of glyphosate. Vulnerability was verified using a starvation test in which significant differences were observed between the control populations and populations with a disturbance history. Both the Control and Vulnerable populations were assessed for their avoidance capacity by exposing them to a glyphosate gradient using a Heterogeneous Multiple-Habitat Assay System (HeMHAS). The control populations showed a rapid reaction from the beginning of the assay, with avoidance rates increasing over 24 h, while vulnerable populations were unable to avoid contaminated habitats for up to 24 h. Therefore, we concluded that vulnerable populations have a lower capacity to avoid contaminated habitats. In heterogeneously contaminated habitats, a lower avoidance capacity is responsible for the differential spatial distribution of the affected species, which impacts the ecosystem structure. Additionally, agrochemically induced vulnerability and its effect on avoidance behaviour may affect ecosystem functioning through the altered spatial distribution of zooplankton populations.

Genetic Diversity and Ecogeographical Niche Overlap Among Hybridising Ox-Eye Daisies (Leucanthemum, Asteraceae) in the Carpathian Mountains: The Impact of Anthropogenic Disturbances

Climate change and human influence are transforming mountain ecosystems, significantly impacting species distributions and biodiversity. Among these changes, the upward migration of lowland species into mountain regions stands out. This study examines the ecogeographical niche overlap and genetic diversity among three Leucanthemum species distributed along an altitudinal gradient in the Carpathian Mountains: the lowland L. ircutianum (4x), the montane L. rotundifolium (2x) and the alpine L. gaudinii (2x). By genotyping over 600 individuals using SNP analysis, followed by principal coordinate analysis (PCoA), Neighbour-Net Network and Structure clustering, we reveal not just distinct genetic groups but also hybridisation across all species, suggesting the potential for triple hybrids. Genetic admixture is further supported by environmental background and niche overlap analyses that reveal substantial overlap among species, particularly in line with their vertical distribution. Climate envelope plots indicate a likely reduction in available habitat for mountainous species due to climate change, leading to an increase in competition and an intensification of hybridisation. Anthropogenic influences are further intensifying these hybridisation trends. Among the studied species, L. gaudinii is most at risk of overwhelming hybridisation, whereas L. ircutianum may experience habitat expansion. By providing a comprehensive genetic and ecological overview, our research highlights the significance of hybridisation in biodiversity conservation and the challenges posed by environmental changes and anthropogenic activities in mountain environments. This study not only contributes to the understanding of genetic diversity in the Carpathians but also underscores the broader implications for molecular ecology and conservation strategies in mountain ecosystems.

Future Healthcare Workers and Ecopharmacovigilance: Where Do We Stand?

With the rapid development of the pharmaceutical industry and constant growth of drug usage, ecopharmacovigilance (EPV) has emerged as a way of coping with and minimizing the effects that drugs have on the environment. EPV concerns and describes unwanted effects that the use of a specific drug could have on the environment. The US, EU and Cananda are the improving position of EPV, both in legislation and practice. EPV requires further development as previous studies have shown that neither the general population nor healthcare professionals have enough knowledge about the subject. Improving awareness and knowledge about this topic is a key task for the future of EPV. The main objective was to determine students' level of knowledge about ecopharmacovigilance and to examine ways of storing and disposing of unused and expired drugs. Students' knowledge and habits were examined by a previously published survey. The survey contains twenty questions divided into three parts and the possibility of writing an additional note. There was no difference in the level of knowledge between the students of different studies. Also, students who had a family member working as healthcare professional did not show a higher level of knowledge compared to the others. Pharmacy students had a greater intention to educate their environment about EPV when compared to students of the other studies. This is in the line with a previous study which showed that the general public expects that pharmacists and physicians educate them about EPV. Medicine and dental medicine students will become prescribers after finishing their studies, and as such, they should be informed about eco-directed sustainable prescribing (EDSP) as part of an EPV strategy. More than half of the participants reported good adherence to prescribers' instruction, which decreased the amount of unused drugs. Most of the students found that the drug expiration date was legible, but they did not check it often. In comparison with similar studies, Croatian students had more knowledge and better practices concerning EPV and drug disposal. Structured learning strategies and curriculum implementation for EPV are much needed for further raising awareness about the subject among healthcare professionals and the public.

Global meta-analysis reveals overall higher nocturnal than diurnal activity in insect communities

Insects sustain key ecosystem functions, but how their activity varies across the day-night cycle and the underlying drivers are poorly understood. Although entomologists generally expect that more insects are active at night, this notion has not been tested with empirical data at the global scale. Here, we assemble 331 quantitative comparisons of the abundances of insects between day and night periods from 78 studies worldwide and use multi-level meta-analytical models to show that insect activity is on average 31.4% (CI: -6.3%-84.3%) higher at night than in the day. We reveal diel preferences of major insect taxa, and observe higher nocturnal activity in aquatic taxa than in terrestrial ones, as well as in warmer environments. In a separate analysis of the small subset of studies quantifying diel patterns in taxonomic richness (31 comparisons from 13 studies), we detect preliminary evidence of higher nocturnal richness in tropical than temperate communities. The higher overall (but variable) nocturnal activity in insect communities underscores the need to address threats such as light pollution and climate warming that may disproportionately impact nocturnal insects.

Warming underpins community turnover in temperate freshwater and terrestrial communities

Rising temperatures are leading to increased prevalence of warm-affinity species in ecosystems, known as thermophilisation. However, factors influencing variation in thermophilisation rates among taxa and ecosystems, particularly freshwater communities with high diversity and high population decline, remain unclear. We analysed compositional change over time in 7123 freshwater and 6201 terrestrial, mostly temperate communities from multiple taxonomic groups. Overall, temperature change was positively linked to thermophilisation in both realms. Extirpated species had lower thermal affinities in terrestrial communities but higher affinities in freshwater communities compared to those persisting over time. Temperature change's impact on thermophilisation varied with community body size, thermal niche breadth, species richness and baseline temperature; these interactive effects were idiosyncratic in the direction and magnitude of their impacts on thermophilisation, both across realms and taxonomic groups. While our findings emphasise the challenges in predicting the consequences of temperature change across communities, conservation strategies should consider these variable responses when attempting to mitigate climate-induced biodiversity loss.

Revealing human impact on natural ecosystems through soil bacterial DNA sampled from an archaeological site

Human activities have affected the surrounding natural ecosystems, including belowground microorganisms, for millennia. Their short- and medium-term effects on the diversity and the composition of soil microbial communities are well-documented, but their lasting effects remain unknown. When unoccupied for centuries, archaeological sites are appropriate for studying the long-term effects of past human occupancy on natural ecosystems, including the soil compartment. In this work, the soil chemical and bacterial compositions were compared between the Roman fort of Hegra (Saudi Arabia) abandoned for 1500 years, and a preserved area located at 120 m of the southern wall of the Roman fort where no human occupancy was detected. We show that the four centuries of human occupancy have deeply and lastingly modified both the soil chemical and bacterial compositions inside the Roman fort. We also highlight different bacterial putative functions between the two areas, notably associated with human occupancy. Finally, this work shows that the use of soils from archaeological sites causes little disruption and can bring relevant information, at a large scale, during the initial surveys of archaeological sites.

The neglected roles of adjacent natural ecosystems in maintaining bacterial diversity in agroecosystems

A central aim of community ecology is to understand how local species diversity is shaped. Agricultural activities are reshaping and filtering soil biodiversity and communities; however, ecological processes that structure agricultural communities have often overlooked the role of the regional species pool, mainly owing to the lack of large datasets across several regions. Here, we conducted a soil survey of 941 plots of agricultural and adjacent natural ecosystems (e.g., forest, wetland, grassland, and desert) in 38 regions across diverse climatic and soil gradients to evaluate whether the regional species pool of soil microbes from adjacent natural ecosystems is important in shaping agricultural soil microbial diversity and completeness. Using a framework of multiscales community assembly, we revealed that the regional species pool was an important predictor of agricultural bacterial diversity and explained a unique variation that cannot be predicted by historical legacy, large-scale environmental factors, and local community assembly processes. Moreover, the species pool effects were associated with microbial dormancy potential, where taxa with higher dormancy potential exhibited stronger species pool effects. Bacterial diversity in regions with higher agricultural intensity was more influenced by species pool effects than that in regions with low intensity, indicating that the maintenance of agricultural biodiversity in high-intensity regions strongly depends on species present in the surrounding landscape. Models for community completeness indicated the positive effect of regional species pool, further implying the community unsaturation and increased potential in bacterial diversity of agricultural ecosystems. Overall, our study reveals the indubitable role of regional species pool from adjacent natural ecosystems in predicting bacterial diversity, which has useful implication for biodiversity management and conservation in agricultural systems.