Survival strategies of human-associated microbes to drug exposure have been mainly studied in the context of bona fide pathogens exposed to antibiotics. Less well understood are the survival strategies of non-pathogenic microbes and host-associated commensal communities to the variety of drugs and xenobiotics to which humans are exposed. The lifestyle of microbial commensals within complex communities offers a variety of ways to adapt to different drug-induced stresses. Here, we review the responses and survival strategies employed by gut commensals when exposed to drugs-antibiotics and non-antibiotics-at the individual and community level. We also discuss the factors influencing the recovery and establishment of a new community structure following drug exposure. These survival strategies are key to the stability and resilience of the gut microbiome, ultimately influencing the overall health and well-being of the host.

In order to evaluate the influence of global warming on the ecosystem processes in marine environments, the changes in colonization dynamics of periphytic microbiota were studied using the periphytic ciliate communities as the test organism fauna under a continuous warming gradient of 22℃ (control), 25℃, 28℃, 31℃, and 34 ℃. The results demonstrated that (1) the test ciliate communities generally showed a similar temporal pattern in within the colonization process under the water temperatures from 22 up to 28℃; however, (2) the colonization dynamics were significantly changed, and the fitness of colonization curves to the MacArthur-Wilson model equation was failed under the temperature increased by 6 ℃, and (3) the loading or assimilative capacity of the test aquatic ecosystem was decreased with the increase of water temperature. Therefore, this study suggests that continuous warming may significantly drive the colonization dynamics of periphytic ciliates in marine ecosystems.

\'Ecosystem function\' and \'ecosystem functioning\' became core keywords in the ecological literature on ecosystems, their structure, development and integrity. We investigate functions from the perspective of causal contributions to higher capacities, as selected effects, as contributions to the stability and self-maintenance of organisms and as type-fixed effects. Based on an in-depth discourse in philosophy of science, we conclude that ecosystems do not have functions in any sense that goes beyond a mere description of a causal contribution. We recommend the terms \'ecosystem function\' and \'ecosystem functioning\' be avoided in the ecological literature (and beyond).

Warming can decrease feeding activity of soil organisms and affect biogeochemical cycles. The ant Formica manchu is active on the nest surface and prefers a hot, dry environment; therefore, warming may provide a favourable environment for its activities. We hypothesized that F. manchu benefit from warming and mitigate the negative effects of warming on litter decomposition. We examined the effects of ant nests (nest absence versus nest presence) and warming (+1.3 and +2.3°C) on litter decomposition, soil properties and the plant community in alpine grassland. Decomposition stations with two mesh sizes were used to differentiate effects of microorganisms (0.05 mm) and macroinvertebrates (1 cm) on decomposition. Ant nests increased litter decomposition with and without macroinvertebrates accessing the decomposition station when compared to plots without ant nests. Only litter decomposition in ant nests with macroinvertebrates having access to the decomposition station was not affected negatively by warming. Plots with ant nests had greater soil carbon, nutrient contents and plant growth than plots without ant nests, regardless of warming. Our results suggest that ant nests maintain ecosystem processes and functions under warming. Consequently, a management strategy in alpine grasslands should include the protection of these ants and ant nests.

Animal migration is a key process underlying active subsidies and species dispersal over long distances, which affects the connectivity and functioning of ecosystems. Despite much research describing patterns of where animals migrate, we still lack a framework for quantifying and predicting how animal migration affects ecosystem processes. In this study, we aim to integrate animal movement behavior and ecosystem functioning by developing a predictive modeling framework that can inform ecosystem management and conservation.We propose a framework to model individual-level migration trajectories between populations\' seasonal ranges as well as the resulting dispersal and fate of propagules carried by the migratory animals, which can be calibrated using empirical data at every step of the modeling process. As a case study, we applied our framework to model the spread of guava seeds, Psidium guajava, by a population of migratory Galapagos tortoises, Chelonoidis porteri, across Santa Cruz Island. Galapagos tortoises are large herbivores that transport seeds and nutrients across the island, while Guava is one of the most problematic invasive species in the Galapagos archipelago.Our model can predict the pattern of spread of guava seeds alongside tortoises\' downslope migration range, and it identified areas most likely to see establishment success. Our results show that Galapagos tortoises\' seed dispersal may particularly contribute to guava range expansion on Santa Cruz Island, due to both long gut retention time and tortoise\'s long-distance migration across vegetation zones. In particular, we predict that tortoises are dispersing a significant amount of guava seeds into the Galapagos National Park, which has important consequences for the native flora.The flexibility and modularity of our framework allow for the integration of multiple data sources. It also allows for a wide range of applications to investigate how migratory animals affect ecosystem processes, including propagule dispersal but also other processes such as nutrient transport across ecosystems. Our framework is also a valuable tool for predicting how animal-mediated propagule dispersal can be affected by environmental change. These different applications can have important conservation implications for the management of ecosystems that include migratory animals.

Functional traits are measurable characteristics that affect an organism\'s fitness under certain environmental conditions. The use of functional traits in microbial ecology holds great promise for improving our ability to develop biogeochemical models and predict ecosystem responses to global changes. Notably, functional traits could be decoupled from taxonomic relatedness, owing to horizontal gene transfer among microorganisms and adaptive evolution. In recent years, our knowledge about microbial functional traits has been substantially enhanced, thereby revealing the multitude of ecological processes in driving community assembly and dynamics. Here, I summarize the emerging patterns of how microbial functional traits respond to changing environments, which considerably differ from better-studied microbial taxonomy. I use niche and neutral theories to explain microbial functional traits. Finally, I highlight future challenges to analyze, elucidate, and utilize functional traits in microbial ecology.

Ecosystem functions underpin productivity and key services to humans, such as food provision. However, as the severity of environmental stressors intensifies, it is becoming increasingly unclear if, and to what extent, critical functions and services can be sustained. This issue is epitomised on coral reefs, an ecosystem at the forefront of environmental transitions. We provide a functional profile of a coral reef ecosystem, linking time-series data to quantified processes. The data reveal a prolonged collapse of ecosystem functions in this previously resilient system. The results suggest that sediment accumulation in algal turfs has led to a decline in resource yields to herbivorous fishes and a decrease in fish-based ecosystem functions, including a collapse of both fish biomass and productivity. Unfortunately, at present, algal turf sediment accumulation is rarely monitored nor managed in coral reef systems. Our examination of functions through time highlights the value of directly assessing functions, their potential vulnerability, and the capacity of algal turf sediments to overwhelm productive high-diversity coral reef ecosystems.

There is growing evidence that both increases in mean temperature and the widespread daily temperature fluctuations (DTF) may increase pesticide toxicity. Nevertheless, the likely more stressful, realistic combination of the two warming-related stressors has rarely been considered in ecotoxicology. Moreover, we have little knowledge on whether these stressor combinations could impair ecosystem functioning. We examined the effect of the pesticide chlorpyrifos under an increased mean temperature (+4 °C, from 18 °C to 22 °C) and in the presence of DTF (constant and 8 °C) on two life-history traits (mortality and growth rate) and one ecologically important behavioural trait (feeding rate) in the freshwater isopod Asellus aquaticus. The chlorpyrifos concentration used, 0.2 μg/L, did not cause mortality in any thermal condition, nor did it cause sublethal effects at the mean temperature of 18 °C. A key finding was that growth rate was strongly reduced by the pesticide only under the combination of both a higher mean temperature and DTF, highlighting the importance of testing toxicity under this realistic thermal scenario. The leaf consumption of chlorpyrifos-exposed isopods increased at the higher mean temperature when this was kept constant, however, it lowered again towards control levels when DTF was induced, thereby contributing to the growth reduction at this most stressful condition. These alterations of growth and leaf degradation rates may impact nutrient recycling, a key ecosystem function. Our results highlight the importance of integrating both increases in mean temperature and in DTF to improve current and future ecological risk assessment of pesticides.

Nitrogen (N2 )-fixing moss microbial communities play key roles in nitrogen cycling of boreal forests. Forest type and leaf litter inputs regulate moss abundance, but how they control moss microbiomes and N2 -fixation remains understudied. We examined the impacts of forest type and broadleaf litter on microbial community composition and N2 -fixation rates of Hylocomium splendens and Pleurozium schreberi. We conducted a moss transplant and leaf litter manipulation experiment at three sites with paired paper birch (Betula neoalaskana) and black spruce (Picea mariana) stands in Alaska. We characterized bacterial communities using marker gene sequencing, determined N2 -fixation rates using stable isotopes (15 N2 ) and measured environmental covariates. Mosses native to and transplanted into spruce stands supported generally higher N2 -fixation and distinct microbial communities compared to similar treatments in birch stands. High leaf litter inputs shifted microbial community composition for both moss species and reduced N2 -fixation rates for H. splendens, which had the highest rates. N2 -fixation was positively associated with several bacterial taxa, including cyanobacteria. The moss microbiome and environmental conditions controlled N2 -fixation at the stand and transplant scales. Predicted shifts from spruce- to deciduous-dominated stands will interact with the relative abundances of mosses supporting different microbiomes and N2 -fixation rates, which could affect stand-level N inputs.

The cascading effects of biodiversity loss on ecosystem functioning of forests have become more apparent. However, how edge effects shape these processes has yet to be established. We assessed how edge effects alter arthropod populations and the strength of any resultant trophic cascades on herbivory rate in tropical forests of Brazil. We established 7 paired forest edge and interior sites. Each site had a vertebrate-exclosure, procedural (exclosure framework with open walls), and control plot (total 42 plots). Forest patches were surrounded by pasture. Understory arthropods and leaf damage were sampled every 4 weeks for 11 months. We used path analysis to determine the strength of trophic cascades in the interior and edge sites. In forest interior exclosures, abundance of predaceous and herbivorous arthropods increased by 326% and 180%, respectively, compared with control plots, and there were significant cascading effects on herbivory. Edge-dwelling invertebrates responded weakly to exclusion and there was no evidence of trophic cascade. Our results suggest that the vertebrate community at forest edges controls invertebrate densities to a lesser extent than it does in the interior. Edge areas can support vertebrate communities with a smaller contingent of insectivores. This allows arthropods to flourish and indirectly accounts for higher levels of plant damage at these sites. Increased herbivory rates may have important consequences for floristic community composition and primary productivity, as well as cascading effects on nutrient cycling. By interspersing natural forest patches with agroforests, instead of pasture, abiotic edge effects can be softened and prevented from penetrating deep into the forest. This would ensure a greater proportion of forest remains habitable for sensitive species and could help retain ecosystem functions in edge zones.
Efectos de Borde sobre las Cascadas Tróficas en los Bosques Tropicales Resumen Los efectos en cascada de la pérdida de la biodiversidad sobre el funcionamiento ecosistémico de los bosques se ha vuelto más evidente. A pesar de ésto, no se ha establecido cómo los efectos de borde moldean estos procesos. Evaluamos cómo los efectos de borde alteran las poblaciones de artrópodos y la fuerza de cualquier cascada trófica resultante sobre la tasa de herbivoría en los bosques tropicales de Brasil. Establecimos siete pares de sitios interiores y en el borde del bosque. Cada sitio tuvo un lote de encierro de vertebrados, uno procesal (un marco de trabajo de encierro con muros abiertos) y uno de control (total de 42 lotes). Los fragmentos de bosque estuvieron rodeados por potreros. Los artrópodos del sotobosque y el daño a las hojas fueron muestreados cada cuatro semanas durante once meses. Usamos el análisis de vía para determinar la fuerza de las cascadas tróficas en los sitios interiores y los del borde. En los encierros ubicados al interior del bosque la abundancia de artrópodos depredadores y herbívoros incrementó en un 326% y 180% respectivamente (comparada con los lotes de control) y hubo efectos relevantes de cascada sobre la herbivoría. Los invertebrados habitantes del borde respondieron débilmente al encierro y no hubo evidencia de la cascada trófica. Nuestros resultados sugieren que la comunidad de vertebrados en los bordes del bosque controla las densidades de invertebrados en un grado menor de lo que lo hace al interior del bosque. Las áreas del borde pueden mantener comunidades de vertebrados con un contingente menor de insectívoros. Ésto permite que los artrópodos florezcan y explica indirectamente los niveles más altos de daño a las plantas en estos sitios. El incremento de las tasas de herbivoría puede tener consecuencias importantes para la composición de la comunidad y para la productividad primaria, así como para los efectos cascada y el ciclo de nutrientes. Si intercalamos los fragmentos de bosque con agrobosques, en lugar de hacerlo con potreros, los efectos abióticos del borde pueden reducirse y se puede prevenir que penetren profundamente en el bosque. Esto aseguraría que una mayor proporción de bosque permanezca como habitable para las especies sensibles y podría ayudar a retener las funciones del ecosistema en las zonas de borde.
生物多样性丧失对森林生态系统功能的级联效应正变得越来越明显。然而, 边缘效应如何影响生态系统过程仍有待确定。本研究评估了巴西热带森林中边缘效应对节肢动物种群的影响, 以及由此产生的营养级联对叶片虫食率的影响。我们确定了 7 对森林边缘和内部的研究位点, 每个位点都分别设有脊椎动物围栏, 程序化围栏 (有围栏结构但墙体开放) 和控制区 (共 42 块区域) 。该地区的森林斑块被牧场环绕。我们在 11 个月中每 4 周采集一次林下节肢动物样本和叶片损伤样本, 并使用路径分析确定了森林内部和边缘位点的营养级联强度。在森林内部的围栏中, 食肉节肢动物和食草节肢动物的丰度与控制区相比分别增加了 326% 和 180%, 且存在显著的对叶片虫食的级联效应。而栖息在森林边缘的无脊椎动物对围栏的反应较弱, 没有证据表明存在营养级联。我们的研究结果表明, 森林边缘的脊椎动物群落对无脊椎动物密度的控制程度低于森林内部。边缘地区可以支持脊椎动物群落, 但食虫动物的数量较少。这使得节肢动物得以大量繁殖, 并间接导致了这些地区植物遭到了较高程度的损伤。虫食率的增加可能对植物区系组成和初级生产力产生重要影响, 并对营养循环产生级联效应。通过在天然森林斑块中交替设置农林复合斑块而非牧场, 可以减弱非生物的边缘效应, 防止其更深入地影响森林内部。这样将确保更大比例的森林仍适合敏感物种栖息, 并有助于保留边缘地带的生态系统功能。【翻译: 胡怡思; 审校: 聂永刚】.