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Changes of distribution and abundance of common birds associated with alterations in the composition and configuration of landscapes in Bulgaria are presented. They are measured by a set of metrics in a model area of abandoned agricultural lands in different stages of vegetation succession. Under such conditions, the edge effect proved to be significant factor for the species composition. The established specific preferences of the farmland and forest specialists as well as the generalist species in four landscape classes (Open Landscapes, Shrubland, Open Forest and Forest) contribute to better understanding of the causes of changes in breeding population trends. These data allow predicting the impact on the habitat bird guilds when developing landscape management plans for protected areas or conservation measures for priority bird species. This approach can increase the effectiveness of the implementation of European agri-environmental measures. [ABSTRACT FROM AUTHOR]

Biotic homogenization is a process whereby species assemblages become more similar through time. The standard way of identifying the process of biotic homogenization is to look for decreases in spatial beta–diversity. However, using a single assemblage‐level metric to assess homogenization can mask important changes in the occupancy patterns of individual species.Here, we analysed changes in the spatial beta–diversity patterns (i.e. biotic heterogenization or homogenization) of British bird assemblages within 30 km × 30 km regions between two periods (1988–1991 and 2008–2011). We partitioned the change in spatial beta–diversity into extirpation and colonization‐resultant change (i.e. change in spatial beta–diversity within each region resulting from both extirpation and colonization). We used measures of abiotic change in combination with Bayesian modelling to disentangle the drivers of biotic heterogenization and homogenization.We detected both heterogenization and homogenization across the two time periods and three measures of diversity (taxonomic, phylogenetic, and functional). In addition, both extirpation and colonization contributed to the observed changes, with heterogenization mainly driven by extirpation and homogenization by colonization. These assemblage‐level changes were primarily due to shifting occupancy patterns of generalist species.Compared to habitat generalists, habitat specialists had significantly (i) higher average contributions to colonization‐resultant change (indicating heterogenization within a region due to colonization) and (ii) lower average contributions to extirpation‐resultant change (indicating homogenization from extirpation). Generalists showed the opposite pattern.Increased extirpation‐resultant homogenization within regions was associated with increased urban land cover and decreased habitat diversity, precipitation, and temperature. Changes in extirpation‐resultant heterogenization and colonization‐resultant heterogenization were associated with differences in elevation between regions and changes in temperature and land cover.Many of the 'winners' (i.e. species that increased in occupancy) were species that had benefitted from conservation action (e.g. buzzard (Buteo buteo)). The 'losers' (i.e. those that decreased in occupancy) consisted primarily of previously common species, such as cuckoo (Cuculus canorus).Our results show that focusing purely on changes in spatial beta–diversity over time may obscure important information about how changes in the occupancy patterns of individual species contribute to homogenization and heterogenization. [ABSTRACT FROM AUTHOR]

In 1950, the leaders of independent India celebrated the contributions that surgeons could make to modernising India. Surgeons, however, faced a difficult choice. Some wanted to invest in generalist surgeons to make basic surgical care available to all Indians. Others wanted to invest in specialists to ensure that India participated in cutting‐edge surgical research and care. These debates shaped the emergence of cardiac surgery at two centres: the Christian Medical College in Vellore and the King Edward Memorial Hospital in Bombay. CMC invested in thoracic surgery in the 1940s to offer new treatments for tuberculosis. This gave surgeons the opportunity to explore new techniques of cardiac surgery. Debate quickly emerged about whether investments in cardiology and cardiac surgery made sense. In the end, the specialities were supported in order to attract paying patients. A parallel controversy took place at KEM, where the dean debated the Bombay Municipal Corporation about the role of surgical research at a public hospital. The Rockefeller Foundation influenced both sites, offering financial support if they adopted an American model of full‐time faculty clinician‐researchers. The two case studies reveal how unusual dynamics could contribute to the establishment of new medical specialities in India. [ABSTRACT FROM AUTHOR]

IntroductionPlant functional traits (FTs) are important for understanding plant ecological strategies (e.g., drought avoidance), especially in the nutrient-poor soils of serpentine ecosystems. In the Mediterranean areas, such ecosystems are characterized by climatic factors (e.g., summer drought) that exert a filtering effect.Material and methodsIn our study, we analyzed 24 species with varying serpentine affinity, from strictly serpentine plants to generalist plants, from two ultramafic shrublands in southern Spain, considering four FTs: plant height (H), leaf area (LA), specific leaf area (SLA), and stem specific density (SSD). Additionally, we also identified the species' dominant strategies to avoid drought and those strategies' relationship to serpentine affinity. We used principal component analysis to identify combinations of FTs, and cluster analysis to define Functional Groups (FGs).Results and discussionWe defined eight FGs, which suggests that such Mediterranean serpentine shrublands are composed of species with wide-ranging of FTs. Indicator traits explained 67-72% of the variability based on four strategies: (1) lower H than in other Mediterranean ecosystems; (2) middling SSD; (3) low LA; and (4) low SLA due to thick and/or dense leaves, which contribute to long leaf survival, nutrient retention, and protection from desiccation and herbivory. Generalist plants had higher SLA than obligate serpentine plants, whereas the obligate serpentine plants showed more drought avoidance mechanisms than the generalists. Although most plant species inhabiting Mediterranean serpentine ecosystems have shown similar ecological adaptations in response to the Mediterranean environment, our results suggest that serpentine obligate plant species could present greater resilience to climate change. Given greater number and more pronounced drought avoidance mechanisms in these species compared with generalists, and the high number of FGs identified, the serpentine plants have shown adaptation to severe drought.

Worldwide, with the decline of natural habitats, species with reduced niche breadth (specialists) are at greater risk of extinction as they cannot colonise or persist in disturbed habitat types. However, the role of thermal tolerance as a critical trait in understanding changes in species diversity in disturbed habitats, e.g., due to forest replacement by tree plantations, is still understudied. To examine the role of thermal tolerance on the responses of specialist and generalist species to habitat disturbances, we measured and compared local temperature throughout the year and thermotolerance traits [upper (CTmax) and lower (CTmin) thermal limits] of the most abundant species of spiders from different guilds inhabiting pine tree plantations and native Atlantic Forests in South America. Following the thermal adaptation hypothesis, we predicted that generalist species would show a wider thermal tolerance range (i.e., lower CTmin and higher CTmax) than forest specialist species. As expected, generalist species showed significantly higher CTmax and lower CTmin values than specialist species with wider thermal tolerance ranges than forest specialist species. These differences are more marked in orb weavers than in aerial hunter spiders. Our study supports the specialisation disturbance and thermal hypotheses. It highlights that habitat-specialist species are more vulnerable to environmental changes associated with vegetation structure and microclimatic conditions. Moreover, thermal tolerance is a key response trait to explain the Atlantic Forest spider's ability (or inability) to colonise and persist in human-productive land uses. [ABSTRACT FROM AUTHOR]

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Generalists are thought to adapt to broader ecological conditions compared to less flexible specialists. However, few studies have systematically tested what ecological or life‐history traits are associated with organisms' ecological flexibility. Here, we used stony corals to test the relative effects of host traits and ecological factors on corals' flexibility to form photosymbioses with algae. We analysed data from 211 stony coral species to test if coral's geographic distribution, depth range, symbiont transmission mode or colony morphology predict coral–algal flexibility. We report a novel positive correlation between coral–algal flexibility and coral species' geographic range. Symbiont transmission mode was also a predictor of flexibility, albeit the result is less robust against sampling bias. Coral depth range and morphology did not show significant effects. We highlight that host–symbiont dispersal abilities, interactions and evolutionary histories likely contribute to the observed patterns. We urge conservation efforts to consider the ecological implications of coral–algal flexibility. [ABSTRACT FROM AUTHOR]

ABSTRACT Beneficial interactions between plants and rhizosphere fungi can enhance plant adaptability during drought stress. However, harnessing these interactions will require an in-depth understanding of the response of fungal community assembly to drought. Herein, by using different varieties of wheat plants, we analyzed the drought-induced changes in fungal community assembly in rhizosphere and bulk soil. We demonstrated that drought significantly altered the fungal communities, with the contribution of species richness to community beta diversity increased in both rhizosphere and bulk soil compartments during drought stress. The stochastic processes dominated fungal community assembly, but the relative importance of deterministic processes, mainly homogeneous selection, increased in the drought-stressed rhizosphere. Drought induced an increase in the relative abundance of generalists in the rhizosphere, as opposed to specialists, and the top 10 abundant taxa that enriched under drought conditions were predominantly generalists. Notably, the most abundant drought-enriched taxon in rhizosphere was a generalist, and the corresponding Chaetomium strain was found capable of improving root length and activating ABA signaling in wheat plants through culture-based experiment. Together, these findings provide evidence that host plants exert a strong influence on rhizospheric fungal community assembly during stress and suggest the fungal communities that have experienced drought have the potential to confer fitness advantages to the host plants.IMPORTANCEWe have presented a framework to integrate the shifts in community assembly processes with plant-soil feedback during drought stress. We found that environmental filtering and host plant selection exert influence on the rhizospheric fungal community assembly, and the re-assembled community has great potential to alleviate plant drought stress. Our study proposes that future research should incorporate ecology with plant, microbiome, and molecular approaches to effectively harness the rhizospheric microbiome for enhancing the resilience of crop production to drought.

BackgroundIn 1978, the World Health Organization (WHO) adopted primary health care (PHC) as the most effective strategy to meet the healthcare needs of communities. This raises the question as to the extent and nature of the training that undergraduate (UG) medical students receive in medical schools regarding PHC, following this statement.AimThe study aim was to explore the experiences of UG medical students and their trainers regarding training in PHC in their institutions.MethodsA qualitative study was conducted among UG medical students (MBChB 4-6) and their trainers at four conveniently selected South African medical schools. A total of 16 focus group discussions (FGDs) and 27 in-depth interviews were conducted among students and their trainers, respectively. The MAXQDA 2020 (Analytics Pro) software program was used to arrange the data, resulting in 2,179 data segments, from which categories, sub-themes and themes were derived.ResultsBoth the UG medical students and their trainers regarded PHC as mainly an approach to health rather than a level of care. Students were trained by specialists and generalists, received training in the undifferentiated patient, coordinated, comprehensive and continuity of care. The training in tertiary centers, conducted mainly by specialists, the implicitness of the training and the inadequacy of trainers at the PHC settings presented challenges.ConclusionStudents and their trainers experienced UG student training in PHC in line with the internationally recognized principles on the subject. The view by students and their trainers that PHC is an approach rather than a level of care enhanced its training across disciplines. The implicitness of the training and the tertiary learning platforms were the main challenges experienced. For optimum PHC training, more time should be dedicated to distributed training platforms with supportive specialist outreach programs in the South African medical schools.

Unravelling the relationships between insect population dynamics and habitat properties is often complex. Established theoretical concepts, which predict an influence of available resources on sex determination, have often not been tested with quantitative field data. Cavity-nesting Hymenoptera are suitable to assess the influence of habitat properties on reproductive parameters, as haplodiploidy enables direct responses to local conditions. We hypothesize that with increasing resource availability, the population sex ratio (share of females per site), sex allocation preference per individual offspring (the probability of producing either a male or a female offspring per brood cell) and resource allocation per individual offspring will be favouring towards females. We sampled offspring of Osmia cornuta, Osmia caerulescens and Trypoxylon figulus and their resource provisions using trap nests on 30 study sites in an agricultural landscape in southwest Germany, from March to August 2020. The potential influence of resource availability, landscape variables, temperature, seasonal progression, and nesting opportunities on sex and resource provisions was tested. Population sex ratio was not related to habitat properties. Sex allocation preference in the three species, however, depended on several variables including cavity size and seasonal progression, with pronounced differences amongst species. Individual resource provisioning mainly differed between sexes, as male larvae received less provisions than female larvae. As there was no influence of resource availability, we conclude that the sex ratio of established populations was balanced at the selected study sites by available resources in the landscape. At the individual scale, sex and resource allocation were influenced in species-specific ways. As such, sex determination and resource allocation are essential life history properties of sexually reproducing organisms.

Studies aim to understand the behavior of human populations when selecting certain groups of plants over others. Some plants are chosen for favorable characteristics that justify specific uses. Thus, individuals may exhibit specialized behavior patterns, selecting plants for fuel based on specific biological traits like ignition potential and durability or generalized behavior patterns, depending on species availability or utilitarian redundancy. However, more is needed to know about how the preference for these resources may be shaped by contexts prohibiting resource use. Prohibiting resource use can compel human groups to devise new selection strategies, leading to significant changes in socioecological system dynamics. Hence, this study aims to investigate how preference for plants used as firewood varies in areas with restricted and unrestricted resource use. We conducted semi-structured interviews in two communities. In the past, participants with restricted access to natural resources exhibited specialist behaviors. However, due to imposed restrictions, the community needed to adopt new usage strategies, resulting in generalized behaviors in the present. The use preference at unrestricted areas varied over time, with individuals being generalists in the past and specialists currently. Based on these behavioral patterns, it is possible to infer that these human groups demonstrate adaptive plasticity to cope with the significant impacts of long-term wood resource extraction. [ABSTRACT FROM AUTHOR]

As concerns about anthropogenic and natural disturbance grow, understanding animal resource use patterns has been increasingly prioritized to predict how changes in environmental conditions, food web structure, and population dynamics will affect biological resilience. Among the tools used to assess resource use, stable isotope analysis has proliferated in ecological studies, particularly in relation to describing intra- and interspecific variation in trophic interactions. Despite a growing need to disseminate scientific information, the inherent limitations of stable isotope ratios and inappropriate synonymizing of distinct evolutionary and ecological processes may mislead ecological inferences in natural systems. This situation necessitates a re-evaluation of the utility of stable isotope ratios to address certain ecological questions. Here, we assess the efficacy of stable isotope ratios to describe two fundamental ecological processes, niche partitioning and individual specialization. Investigation of these processes has increased substantially in accordance with increased access to stable isotope data. This article discusses the circumstances and approaches that are necessary to evaluate niche partitioning and individual specialization, and outlines key considerations for the associated application of stable isotope ratios.

Background: The definition of Primary Health Care (PHC) issued by the World Health Organisation in 1978 indicated that essential health care should be made accessible to individuals and their communities close to where they live and work. In 1992 Starfield articulated the four pillars of PHC: the patient's first contact with healthcare, comprehensive care, coordinated care and continuous care. Using this literature guidance, this study sought to explore what undergraduate medical students and their clinical preceptors understood by PHC in four South African medical schools. Methods: A qualitative study using the phenomenological design was conducted among undergraduate medical students and their clinical preceptors. The setting was four medical schools in South Africa (Sefako Makgatho Health Sciences University, Walter Sisulu University and the University of KwaZulu-Natal and the Witwatersrand University). A total of 27 in-depth interviews were conducted among the clinical preceptors and 16 focus group discussions among the students who were in their clinical years of training (MBChB 4–6). Interviews were digitally recorded and transcribed verbatim, followed by thematic data analysis using the MAXQDA 2020 (Analytics Pro) software. Results: Four themes were identified in which there were similarities between the students and their preceptors regarding their understanding of PHC: (1) PHC as the patient's first contact with the healthcare system; (2) comprehensive care; (3) coordination of care and (4) continuity of care. A further two themes were identified in which these two groups were not of similar understanding: (5) PHC as a level or an approach to healthcare and (6) the role of specialist clinical preceptors in PHC. Conclusions: Medical students and their clinical preceptors displayed an understanding of PHC in line with four pillars articulated by Starfield and the WHO definition of PHC. However, there remains areas of divergence, on which the medical schools should follow the guidance provided by the WHO and Starfield for a holistic understanding of PHC. [ABSTRACT FROM AUTHOR]

During a cold La Niña period (August 2007–January 2008) in the central Galápagos archipelago, 70% of Pocillopora branching corals were severely bleached across three long‐term monitoring sites, affording an opportunity to examine its impact on the persistence of these corals and their associated community of fish and mobile macroinvertebrates. Using a time series empirical approach, we tagged and tracked the fate of 96 coral heads and their associates. When surveyed in July 2008, recovered live and dead corals that were previously severely bleached supported similar levels of species richness (randomized observed and estimated Chao 1). By contrast, richness on the surviving live corals remained fairly stable, while Chao 1 estimated richness on dead corals underwent a nearly 50% increase between July and January 2009, thereafter declining to 50% of originally surveyed richness by February 2010. This nonlinear change in species richness was largely due to an influx and decline in opportunistic generalists including pencil urchin bioeroders, gastropod snails, and hermit crabs that colonized dead corals and fed on sessile invertebrates and algae that had initially recruited to dead and undefended coral substrate. Thus, dead corals retained high overall species richness until live corals had recovered, after which richness declined as dead corals eroded and disintegrated (July 2011). Live corals attracted a less speciose but stable assemblage of mutualistic xanthid crabs and fishes that increased in abundance over time with the recovery and growth of live coral tissue. Overall, coral status (live/dead), planar area and maximum branch length predicted the number of species associated with each colony. The delayed diversity loss of associated species following La Niña disturbance to a foundation species represents a local extinction debt of 32–49‐month duration. A better understanding of the scale of extinction debt in foundational marine ecosystems is needed to quantify the breadth of impacts of climate oscillations on biodiversity and ecosystem functioning. [ABSTRACT FROM AUTHOR]

Expert knowledge is used in the development of wildlife habitat suitability models (HSMs) for management and conservation decisions. However, the consistency of such models has been questioned. Focusing on 1 method for elicitation, the analytic hierarchy process, we generated expert‐based HSMs for 4 felid species: 2 forest specialists (ocelot [Leopardus pardalis] and margay [Leopardus wiedii]) and 2 habitat generalist species (Pampas cat [Leopardus colocola] and puma [Puma concolor]). Using these HSMs, species detections from camera‐trap surveys, and generalized linear models, we assessed the effect of study species and expert attributes on the correspondence between expert models and camera‐trap detections. We also examined whether aggregation of participant responses and iterative feedback improved model performance. We ran 160 HSMs and found that models for specialist species showed higher correspondence with camera‐trap detections (AUC [area under the receiver operating characteristic curve] >0.7) than those for generalists (AUC < 0.7). Model correspondence increased as participant years of experience in the study area increased, but only for the understudied generalist species, Pampas cat (β = 0.024 [SE 0.007]). No other participant attribute was associated with model correspondence. Feedback and revision of models improved model correspondence, and aggregating judgments across multiple participants improved correspondence only for specialist species. The average correspondence of aggregated judgments increased as group size increased but leveled off after 5 experts for all species. Our results suggest that correspondence between expert models and empirical surveys increases as habitat specialization increases. We encourage inclusion of participants knowledgeable of the study area and model validation for expert‐based modeling of understudied and generalist species. [ABSTRACT FROM AUTHOR]

We integrated stomach content analysis (SCA) and stable isotope analysis (SIA) to understand ontogenetic niche shifts in the invasive freshwater fish, bluegill, Lepomis macrochirus, inhabiting the Yedang Reservoir in Korea. Based on the total length (TL), we classified L. macrochirus as small (23–57 mm), medium (61–99 mm), or large (100–163 mm). Across all study sites, the index of relative importance (IRI) of zooplankton was high for small individuals, whereas those of benthic macroinvertebrates were high for the medium and large groups. Isotopic niche width estimates based on carbon and nitrogen isotope ratios (δ space) also increased with growth, indicating an ontogenetic niche shift in L. macrochirus. In particular, the δ space and diet plasticity of large fish was higher in the littoral population, implying L. macrochirus are generalist feeders as adults. Individuals classified as small showed confined and constant δ space, regardless of habitat condition. Thus, together with the results on the significantly high IRI of zooplankton, these individuals seem to have strong specialistic feeding ecology. Our study demonstrates the applicability strength of combining SCA and SIA for ecological niche research by providing clear evidence of an ontogenetic niche shift in L. macrochirus and elucidates their feeding ecology. [ABSTRACT FROM AUTHOR]

Unravelling the relationships between insect population dynamics and habitat properties is often complex. Established theoretical concepts, which predict an influence of available resources on sex determination, have often not been tested with quantitative field data. Cavity-nesting Hymenoptera are suitable to assess the influence of habitat properties on reproductive parameters, as haplodiploidy enables direct responses to local conditions. We hypothesize that with increasing resource availability, the population sex ratio (share of females per site), sex allocation preference per individual offspring (the probability of producing either a male or a female offspring per brood cell) and resource allocation per individual offspring will be favouring towards females. We sampled offspring of Osmia cornuta, Osmia caerulescens and Trypoxylon figulus and their resource provisions using trap nests on 30 study sites in an agricultural landscape in southwest Germany, from March to August 2020. The potential influence of resource availability, landscape variables, temperature, seasonal progression, and nesting opportunities on sex and resource provisions was tested. Population sex ratio was not related to habitat properties. Sex allocation preference in the three species, however, depended on several variables including cavity size and seasonal progression, with pronounced differences amongst species. Individual resource provisioning mainly differed between sexes, as male larvae received less provisions than female larvae. As there was no influence of resource availability, we conclude that the sex ratio of established populations was balanced at the selected study sites by available resources in the landscape. At the individual scale, sex and resource allocation were influenced in species-specific ways. As such, sex determination and resource allocation are essential life history properties of sexually reproducing organisms. [ABSTRACT FROM AUTHOR]

Natural environments can present diverse challenges, but some genotypes remain fit across many environments. Such "generalists" can be hard to evolve, outcompeted by specialists fitter in any particular environment. Here, inspired by the search for broadly neutralizing antibodies during B cell affinity maturation, we demonstrate that environmental changes on an intermediate timescale can reliably evolve generalists, even when faster or slower environmental changes are unable to do so. We find that changing environments on timescales comparable with evolutionary transients in a population enhance the rate of evolving generalists from specialists, without enhancing the reverse process. The yield of generalists is further increased in more complex dynamic environments, such as a "chirp" of increasing frequency. Our work offers design principles for how nonequilibrium fitness "seascapes" can dynamically funnel populations to genotypes unobtainable in static environments.

Questions: Conservation and restoration efforts can greatly benefit from understanding how plant community specialisation changes after disturbance. This paper addresses general successional patterns concerning the following questions: How does community specialisation change during succession? What are the general patterns in the occurrence of generalists and specialists? What are the general ecological strategies of generalists and specialists? Are threatened species better represented among specialists, as generally expected? Location: Czech Republic, central Europe. Methods: We assessed trends in plant community specialisation as well as the participation of generalists and specialists in 12 types of successional series based on a large data set of dated plots of spontaneously established vegetation at various disturbed sites. We classified species into generalists and specialists using a co‐occurrence specialisation metric, determined overall community specialisation at the plot level, and assessed trends in response to successional age for each of the seres using regression analyses, community‐weighted means and the fourth‐corner approach. We also examined the differences between generalists and specialists during succession by comparing their ecological strategies (competitive, stress‐tolerant and ruderal) and conservation status. Results: Community specialisation generally increased during succession, mainly due to a decline in generalists and an increase in typical species of particular habitats such as grasslands, woodlands and wetlands. Despite the general increase in community specialisation, specialists peaked in early and old successional stages and were always less abundant than generalists. During succession, generalists were more stable in their ecological strategies and were predominantly competitive. Specialists varied more, being mostly competitive stress tolerators but also ruderals in early successional stages. Specialists were proportionally more threatened than generalists. Conclusions: Generalists and specialists differ in their successional patterns, ecological strategies and conservation status. Assessing the spatio‐temporal changes in community specialisation helps to evaluate and track successional trends, and to determine the conservation and restoration status of degraded areas. [ABSTRACT FROM AUTHOR]

It is hypothesized that the contrast observed between different Cambrian and Ordovician diversity trends could be explained by an ecological process linking animal dispersal with speciation and extinction rates. During the Early Ordovician (possibly earlier), local dispersal (within the same region) occurred asynchronously. When dispersal occurred following environmental changes, invading taxa could have triggered the disappearance of specialized ones, that were unable to adapt to these changes, eventually leading to increased extinction rates. Where local dispersal did not occur, the increase in diversity would have not been obscured by extinctions. This complex interplay of events during the Early Ordovician gave rise to intricate diversity patterns in the Middle Ordovician. The Middle Ordovician is characterized by a particular palaeogeographical context favouring speciation during episodes of inter-regional dispersal. Speciation rates would be partially obscured if local dispersal did not occur in the Early Ordovician, as more specialized taxa that survived the Early Ordovician will eventually go extinct during regional Middle Ordovician dispersal. As such, the contrasting diversity trends may be the result of the asynchronicity of dispersal between animal groups and regions during the Cambrian and the Ordovician. [ABSTRACT FROM AUTHOR]

Aim: The small‐island effect (SIE), as an exception to the species–area relationship, has received much attention in true island systems. However, the prevalence and related patterns of the SIE have not been well evaluated in habitat island systems. Here, we aimed to identify the existence of SIE for habitat islands in fragmented landscapes and determine the key factors influencing species richness on small habitat islands. Location: Inner Mongolia Autonomous Region, China. Taxon: Vascular plants. Methods: Based on 78 grassland fragments in fragmented landscapes of the agro‐pastoral ecotone of northern China, we used piecewise regression, path analysis and null models to investigate the SIE of the species–area relationship. We then used a multi‐model selection to evaluate the impacts of four influencing factors (instability, isolation, habitat heterogeneity and surrounding productivity) on species richness (including habitat specialists and generalists) on small habitat islands within the range of SIE. Results: We found an obvious threshold of 5.1 ha in the species–area relationship, below which habitat island area had no direct and indirect effects on species richness. Small habitat islands (<5.1 ha) host a lower percentage of habitat specialists and a higher percentage of generalists. On small habitat islands, species richness was positively affected by habitat heterogeneity while negatively affected by instability and isolation. Habitat heterogeneity had the strongest effect on species richness, positively affecting specialist richness while negatively affecting generalist richness. Main Conclusions: There is an SIE in fragmented landscapes of the agro‐pastoral ecotone of northern China, which should be considered in biodiversity conservation. Habitat heterogeneity had a key role in determining the pattern of species richness, especially for small islands. Habitat specialists and generalists had different SIE‐related patterns. Our study highlights the importance of considering different ecological groups of species to improve our understanding of the SIE in fragmented habitats. [ABSTRACT FROM AUTHOR]

ABSTRACT To what extent are generalist species cohesive evolutionary units rather than a compilation of recently diverged lineages? We examine this question in the context of host specificity and geographic structure in the insect pathogen and nematode mutualist Xenorhabdus bovienii. This bacterial species partners with multiple nematode species across two clades in the genus Steinernema. We sequenced the genomes of 42 X. bovienii strains isolated from four different nematode species and three field sites within a 240-km2 region and compared them to globally available reference genomes. We hypothesized that X. bovienii would comprise several host-specific lineages, such that bacterial and nematode phylogenies would be largely congruent. Alternatively, we hypothesized that spatial proximity might be a dominant signal, as increasing geographic distance might lower shared selective pressures and opportunities for gene flow. We found partial support for both hypotheses. Isolates clustered largely by nematode host species but did not strictly match the nematode phylogeny, indicating that shifts in symbiont associations across nematode species and clades have occurred. Furthermore, both genetic similarity and gene flow decreased with geographic distance across nematode species, suggesting differentiation and constraints on gene flow across both factors, although no absolute barriers to gene flow were observed across the regional isolates. Several genes associated with biotic interactions were found to be undergoing selective sweeps within this regional population. The interactions included several insect toxins and genes implicated in microbial competition. Thus, gene flow maintains cohesiveness across host associations in this symbiont and may facilitate adaptive responses to a multipartite selective environment. IMPORTANCE Microbial populations and species are notoriously hard to delineate. We used a population genomics approach to examine the population structure and the spatial scale of gene flow in Xenorhabdus bovienii, an intriguing species that is both a specialized mutualistic symbiont of nematodes and a broadly virulent insect pathogen. We found a strong signature of nematode host association, as well as evidence for gene flow connecting isolates associated with different nematode host species and collected from distinct study sites. Furthermore, we saw signatures of selective sweeps for genes involved with nematode host associations, insect pathogenicity, and microbial competition. Thus, X. bovienii exemplifies the growing consensus that recombination not only maintains cohesion but can also allow the spread of niche-beneficial alleles.

Abstract Background Landfills are a major subsidy for some animals, with implications for their life history and demography. Gulls feed extensively on food from landfills and closures are expected to have ecological consequences, but how this influences movement ecology is virtually unknown. Methods We used GPS-tracking to quantify foraging behaviour and habitat choice of lesser black-backed gulls (Larus fuscus) breeding at two colonies before and after closure of two nearby landfills. Results Following closure, gulls from both colonies travelled further and for longer to forage. Gulls also changed habitat selection, although this differed by colony - birds from one colony shifted to agricultural habitats, while at the other, increased their use of urban areas. These behavioural responses had no effect on adult body condition but hint at potential direct effects of higher foraging costs and indirect impacts by shifting to new habitats. Conclusions Our results demonstrate how landfill availability influences gull foraging movements and habitat selection. We also emphasize the value of biologging to detect rapid behavioural responses in contrast to more conventional demographic approaches, which is especially important for animals that spend the majority of their lives away from direct observation.

Biological invasions are regarded as a major threat to native biodiversity, with cascading ecological and economic consequences within invaded areas. Anticipating and managing these invasions requires a better understanding of the interactions between non-native and native species. We compiled a list of alien plant species and their native insect herbivores from various terrestrial habitats in the Kashmir Himalaya. On alien plants, a total of 15 native insect herbivores were found, four of which were specialists (Aglais caschmirensis on Urtica dioica, Agrotis sp. and Chrysolina herbacea on Mentha longifolia and Nezara viridula on Verbascum thapsus) and the rest were generalists. Altica himensis is the most common native insect herbivore, feeding on nearly 31 alien plants. Various diversity indices show a quantitative estimate of the alien plant and native insect herbivore network. A total of 42 alien plants were recorded throughout the course of 2 years (2018–2020), with Plantago major having the highest relative abundance of 9.7. The study provides a baseline information on the challenging issue of biological invasion by highlighting the role of native insect herbivores as natural biocontrol agents against invasive alien plants. [ABSTRACT FROM AUTHOR]

Accumulating evidence suggests that herbivorous insects influence the local composition and richness of Neotropical plant species, particularly in species‐rich genera. Species richness, phylogenetic diversity, and chemical diversity all influence the ability of insect herbivores to find and utilize their hosts. The relative impact of these components of diversity on species coexistence and plant–herbivore interactions is not well understood. We constructed 60 local communities of up to 13 species of Piper (Piperaceae) in native, mature forest at a lowland wet forest location in Costa Rica. The species composition of each community was chosen such that species richness, phylogenetic diversity, and GCMS‐based chemical diversity were varied independently among communities. We predicted that chemical diversity would most strongly affect the communities across time, with smaller effects of taxonomic and phylogenetic diversity. At 13 months after the experimental planting, we assessed survivorship of each cutting, measured total leaf area loss of the survivors, leaf area loss to generalist and specialist herbivorous insect species, and local extinction of species. Generalist and specialist herbivory decreased with increasing levels of species richness and phylogenetic diversity, respectively. Surprisingly, there was no independent effect of chemical diversity on any of the three measures of herbivore damage. Nevertheless, plots with a higher chemical and phylogenetic diversity showed decreased plant mortality and local species extinction. Overall, our results suggested that both chemical and phylogenetic similarity are important factors in the assembly and maintenance of tropical plant communities. The fact that chemical diversity influences plant mortality suggests that leaf herbivores, and possibly other plant natural enemies, could increase plant diversity via the selective mortality of similar chemotypes. [ABSTRACT FROM AUTHOR]

Questions: What are the effects of environmental and dispersal filters on vegetation in small and species‐rich fragments of temperate forests in which species richness increases along the edge–interior gradient? Location: Small fragments of thermophilic forests in central Bohemia, Czech Republic. Methods: Repeated vegetation surveys and seed rain samplings were conducted in 71 plots located in 17 forest fragments (0.4 to 255 ha) in an agricultural landscape in Central Europe. A subsequent assessment of seed viability was performed via germination in a greenhouse. We evaluated species richness, composition and the similarities between forest vegetation and viable available seeds, accounting for potentially significant environmental conditions. Particularly, we examined the effects of species with different associations to the forest environment in combination with prevalent dispersal strategies. Results: Species richness and composition of the herb layer vegetation (including tree and shrub seedlings) in small forest fragments reflected seed distribution and, to a lesser extent, seed viability. Plant species composition showed a nested pattern according to the distance from the forest edge; the species at the edge represented a subset of the species in the forest interior. Forest specialist species with spatially limited dispersal consistently achieved the highest species richness in forest interiors (>200 m from the forest edge), although this differed depending on aspect. Species richness of generalists and open‐land species benefitted from higher light quality and vice versa for forest specialists. Conclusions: Small forest fragments maintain species‐rich herb layer communities confined in area‐limited interior habitats. They do this despite being mostly or entirely under the influence of the edge effect and impoverished of forest specialists. Moreover, the species‐rich interiors of the small forest fragments are likely prone to negative changes in species composition induced either by canopy closure or opening in the future. [ABSTRACT FROM AUTHOR]

Polyphagous insects often show specialization in feeding on different host plants in terms of survival and growth and, therefore, can be considered minor or major pests of particular hosts. Whether polyphagous insects employ a common transcriptional response to cope with defenses from diverse host plants is under‐studied. We focused on patterns of transcriptional plasticity in polyphagous moths (Noctuidae), of which many species are notorious pests, in relation to herbivore performance on different host plants. We compared the transcriptional plasticity of five polyphagous moth species feeding and developing on three different host plant species. Using a comparative phylogenetic framework, we evaluated if successful herbivory, as measured by larval performance, is determined by a shared or lineage‐specific transcriptional response. The upregulated transcriptional activity, or gene expression pattern, of larvae feeding on the different host plants and artificial control diet was highly plastic and moth species‐specific. Specialization, defined as high herbivore success for specific host plants, was not generally linked to a lower number of induced genes. Moths that were more distantly related and showing high herbivore success for certain host plants showed shared expression of multiple homologous genes, indicating convergence. We further observed specific transcriptional responses within phylogenetic lineages. These expression patterns for specific host plant species are likely caused by shared evolutionary histories, for example, symplesiomorphic patterns, and could therefore not be associated with herbivore success alone. Multiple gene families, with roles in plant digestion and detoxification, were widely expressed in response to host plant feeding but again showed highly moth species‐specific. Consequently, high herbivore success for specific host plants is also driven by species‐specific transcriptional plasticity. Thus, potential pest moths display a complex and species‐specific transcriptional plasticity. [ABSTRACT FROM AUTHOR]

Fungi are an important component of microbial communities that serve a variety of important roles in nutrient cycling and are essential for plant nutrient uptake in forest soils. Distance decay of similarity (DDS) is one of the few ubiquitous phenomena in community ecology. However, the contribution of specialist and generalist fungal species in shaping DDS remains poorly investigated. Through removing operational taxonomic units (OTU) with low or high frequencies, we rigorously quantified the impact of specialists or generalists on the change in slope, initial similarity, and halving distance of DDS of undefined saprotroph, plant mutualist, and plant putative pathogen communities in a 20-ha subtropical evergreen forest plot in Yunnan Province, Southwest China. We hypothesized that (1) the soil fungal co-occurrence networks are different between the three fungal guilds; (2) specialists and generalists contribute to the spatial turnover and nestedness of beta diversity, respectively; and (3) the removal of specialists or generalists will have opposite effects on the change of slope, initial similarity, and halving distance of DDS. Co-occurrence network analysis showed that the undefined saprotroph network had a much more complicated structure than mutualist and pathogen networks. Ascomycota and Basidiomycota were the two most abundant phyla in soil fungal communities. We found that partly in line with our expectations, the change in initial similarity increased and decreased when removing specialists and generalists, respectively, but there was always one exception guild of out of the three communities for the change in slope and halving distance. We identified that such change was mainly due to the change in turnover and nestedness of beta diversity. Furthermore, the results show that species turnover rather than species nestedness drove fungal beta diversity across functional guilds for both specialists and generalists. [ABSTRACT FROM AUTHOR]

Soil protists have vital roles as major microbiome predators in soil functioning and plant performance. Protists are also suggested to be the most responsive microbial group to external changes, such as anthropogenic land use types. While protists were long used as models for biogeography such as to investigate if 'everything is everywhere' among microbes, their biogeography at the taxonomic level has never been explored in depth at the continental scale and linked to anthropogenic drivers. Here we evaluated how land-use types affect the diversity and structure of soil protist communities across 885 locations in Europe based on the European Commission's Land Use and Coverage Area frame Survey (LUCAS). We observed higher α-diversity of soil protists but lower community structure dissimilarity (β-diversity) in croplands compared with woodlands, with grasslands in an intermediate position. The diversity of protist groups with a broader spatial niche was higher in croplands, whereas taxa with a narrower niche increased in woodlands. The importance of climate factors on α-diversity variations reduced as land use intensity increased, but the opposite trend was observed for the effect of soil properties. Our study suggests that there is an interaction between land use type, environmental effects, and spatial niche attributes of soil protist groups, highlighting the importance of land-use type on the dynamics of protist communities. • Land use intensity affect α- and β-diversity of soil protist groups in an opposite manner. • There were interactions between environmental effects and land use types on α-diversity. • Generalist protists tend to be more diverse in more intensive land use types. [ABSTRACT FROM AUTHOR]

Plants produce multiple specialised metabolites to defend themselves against insect herbivores. Phytochemical diversity plays important roles in plant–insect interactions, but specific roles of its various dimensions are poorly known. Interspecific chemical β‐diversity represents variation in presence of species‐specific metabolites or quantitative variation in concentrations of metabolites common to several plant species.We hypothesised that qualitative and quantitative variation in plant chemistry can have differential effects on herbivores from various insect orders.We linked phytochemical variation in willow salicylates (Salicaceae‐specific metabolites) and flavonoids (widespread metabolites) to a standardised distance‐based specialisation index (DSI*) in three orders of leaf‐chewing insects: sawfly larvae, beetles, and caterpillars.In beetles, average DSI* accounting for host chemical β‐diversity did not differ from DSI* disregarding host chemistry. Levels of chemical specialisation did not differ among beetle species feeding only on Salicaceae and those using other plant families, suggesting that both can overcome willow chemistry by alternative physiological or behavioural adaptations. Contrastingly, sawflies and caterpillars responded to willow chemistry, with their DSI* corresponding mainly to quantitative differences in willow metabolites. The DSI* accounting for salicylates did not differ from the one accounting for flavonoids in either of the two orders.Our results suggest that β‐diversity in plant chemistry has differential effects on insect herbivores depending on their order and chemical β‐diversity measurement used. Our results emphasise the importance of quantitative variation in plant chemical composition, suggesting that it does not always have to be rare or species‐specific metabolites that drive host‐choice of leaf‐chewing insects. [ABSTRACT FROM AUTHOR]

The issue of trade-offs among traits is of special interest in evolutionary ecology. We hypothesized that the temperature-size rule (TSR) may be affected by the level of thermal specialization and that this pattern may be traded off with the temperature-dependent potential for population growth rate. We used six parthenogenetic rotifer clones previously exposed to different thermal conditions. We tested hypotheses on the relationships between (i) thermal acclimation and clone body size, (ii) thermal preference and fitness, and (iii) thermal specialization and strength of the TSR (the slope of response). Positive verification of (i) makes it justifiable to refer the other investigated traits as thermal preference. Addressing the issues (ii) and (iii) is our pioneering contribution to the question of whether the strength of the size-to-temperature response differs across life strategies. Interclonal differences in female body size were examined in common garden conditions at 25 °C. We estimated the population growth rate and strength (= slope) of the size-to-temperature response across four thermal regimes: 15, 20, 25, and 30 °C. Thermal acclimation of the clones was related to body size, with clones acclimated to higher temperatures being smaller. Warm-acclimated clones had a narrower thermal range (= were more specialized). The TSR was stronger in rotifers acclimated to intermediate thermal conditions than in specialists. [ABSTRACT FROM AUTHOR]

Insect herbivores are relatively specialized. Why this is so is not clear. We examine assumptions about associations between local abundance and dietary specialization using an 18‐year data set of caterpillar–plant interactions in Ecuador. Our data consist of caterpillar–plant associations and include standardized plot‐based samples and general collections of caterpillars, allowing for diet breadth and abundance estimates across spatial scales for 1917 morphospecies. We find that more specialized caterpillars are locally more abundant than generalists, consistent with a key component of the 'jack of all trades, master of none' hypothesis. As the diet breadth of species increased, generalists were not as abundant in any one location, but they had broader occupancy across the landscape, which is a pattern that could reflect high plant beta diversity and is consistent with an alternative neutral hypothesis. Our finding that more specialized species can be both rare and common highlights the ecological complexity of specialization. [ABSTRACT FROM AUTHOR]

(1) Background: We aimed to determine whether physicians of different specialties perform differently in the monitoring, cost control, and prevention of acute outcomes in diabetes care. (2) Methods: Using data from the Health and Welfare Data Science Center, participants with newly diagnosed type 2 diabetes (n = 206,819) were classified into three cohorts based on their primary care physician during the first year of diagnosis: family medicine (FM), endocrinologist, and other internal medicine (IM). The three cohorts were matched in a pairwise manner (FM (n = 28,269) vs. IM (n = 28,269); FM (n = 23,407) vs. endocrinologist (n = 23,407); IM (n = 43,693) vs. endocrinologist (n = 43,693)) and evaluated for process indicators, expenditure on diabetes care, and incidence of acute complications (using subdistribution hazard ratio; sHR). (3) Results: Compared to the FM cohort, both the IM (sHR, 1.26; 95% CI, 1.08 to 1.47) and endocrinologist cohorts (sHR, 1.57; 95% CI, 1.38–1.78) had higher incidences of acute complications. The FM cohort incurred lower costs than the IM cohort (USD 487.41 vs. USD 507.67, p = 0.01) and expended less than half of the diabetes-related costs of the endocrinology cohort (USD 484.39 vs. USD 927.85, p < 0.001). (4) Conclusion: Family physicians may provide better care at a lower cost to newly diagnosed type 2 diabetes patients. Relatively higher costs incurred by other internists and endocrinologists in the process of diabetes care may be explained by the more frequent ordering of specialized tests. [ABSTRACT FROM AUTHOR]

Organizational involvement in stigmatized practices, that is, practices that attract substantial societal condemnation, is often challenging, inasmuch as it requires the successful management of stakeholder disapproval. In this regard, existing work on organizational stigma has highlighted the advantages of situating stigmatized practices within large, generalist organizations, because doing so allows for stigma dilution—that is, organizations can reduce stakeholder disapproval by increasing their relative engagement in uncontested practices, thereby straddling multiple categories in the eyes of audiences. This line of argument, however, runs counter to the empirical observation that stigmatized practices often remain overwhelmingly concentrated within smaller, specialist organizations, even though these are often not optimally positioned to cope with stigma. In this paper, therefore, we undertake an in-depth historical analysis of a revelatory case—abortion provision in the United States following the landmark Roe v. Wade U.S. Supreme Court decision—to build theory of how stigmatized categories can come to be populated predominantly by specialists. Building on primary and secondary archival materials, we identify three mechanisms that shaped category evolution and resulted in the de facto segregation of abortion into specialist organizations: the founding of freestanding facilities by values-driven providers, the exit of generalist organizations from the category, and the involuntary specialization of remaining providers, as customers no longer frequented them for other services and they soon became labeled simply as "abortion clinics." We conclude by discussing the implications of our findings for the stigma literature and the generalizability of our theorizing to other settings. [ABSTRACT FROM AUTHOR]

Understanding the molecular mechanisms that determine a species' life history is important for predicting their susceptibility to environmental change. While specialist species with a narrow niche breadth (NB) maximize their fitness in their optimum habitat, generalists with broad NB adapt to multiple environments. The main objective of this study was to identify general transcriptional patterns that would distinguish bacterial strains characterized by contrasted NBs along a salinity gradient. More specifically, we hypothesized that genes encoding fitness‐related traits, such as biomass production, have a higher degree of transcriptional regulation in specialists than in generalists, because the fitness of specialists is more variable under environmental change. By contrast, we expected that generalists would exhibit enhanced transcriptional regulation of genes encoding traits that protect them against cellular damage. To test these hypotheses, we assessed the transcriptional regulation of fitness‐related and adaptation‐related genes of 11 bacterial strains in relation to their NB and stress exposure under changing salinity conditions. The results suggested that transcriptional regulation levels of fitness‐ and adaptation‐related genes correlated with the NB and/or the stress exposure of the inspected strains. We further identified a shortlist of candidate stress marker genes that could be used in future studies to monitor the susceptibility of bacterial populations or communities to environmental changes. [ABSTRACT FROM AUTHOR]

Abstract To adapt to ecological and environmental conditions, species can change their ecological niche (e.g., interactions among species) and function (e.g., prey‐predation, diet competition, and habitat segregation) at the species and guild levels. Stable isotope analysis of bulk carbon and nitrogen of organisms has conventionally been used to evaluate such adaptabilities in the scenopoetic and bionomic views as the isotopic niche width. Compound‐specific stable isotope analysis (CSIA) of nitrogen within amino acids provides trophic information without any disruption of scenopoetic views in the isotope ratios, unlike conventional bulk isotope analysis provides both information and therefore frequently hinders its usefulness for trophic information. We performed CSIA of amino acids to understand the trophic variability of the pike gudgeon Pseudogobio esocinus and largemouth bass Micropterus salmoides as representative specialist and generalist fish species, respectively, from 16 ecologically variable habitats in the four major rivers of Korea. There was little variation (1σ) in the trophic position (TP) among habitats for P. esocinus (± 0.2); however, there was considerably large variation for M. salmoides (± 0.6). The TP of M. salmoides was negatively correlated with the benthic invertebrate indices of the habitats, whereas the TP of P. esocinus showed no significant correlation with any indices. Thus, these two representative fish species have different trophic responses to ecological conditions, which is related to known differences in the trophic niche between specialists (i.e., small niche width) and generalists (i.e., large niche width). Over the past four decades, the conventional bulk isotope analysis has not been capable of deconvoluting “scenopoetic” and “bionomic” information. However, in the present study, we demonstrated that the CSIA of amino acids could isolate trophic niches from the traditional ecological niche composed of trophic and habitat information and evaluated how biological and ecological indices influence the trophic response of specialists and generalists.

Summary: Forests harbour large spatiotemporal heterogeneity in canopy structure. This variation drives the microclimate and light availability at the forest floor. So far, we do not know how light availability and sub‐canopy temperature interactively mediate the impact of macroclimate warming on understorey communities.We therefore assessed the functional response of understorey plant communities to warming and light addition in a full factorial experiment installed in temperate deciduous forests across Europe along natural microclimate, light and macroclimate gradients. Furthermore, we related these functional responses to the species' life‐history syndromes and thermal niches.We found no significant community responses to the warming treatment. The light treatment, however, had a stronger impact on communities, mainly due to responses by fast‐colonizing generalists and not by slow‐colonizing forest specialists. The forest structure strongly mediated the response to light addition and also had a clear impact on functional traits and total plant cover.The effects of short‐term experimental warming were small and suggest a time‐lag in the response of understorey species to climate change. Canopy disturbance, for instance due to drought, pests or logging, has a strong and immediate impact and particularly favours generalists in the understorey in structurally complex forests. [ABSTRACT FROM AUTHOR]

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Mammalian dung represents a primary feeding and reproductive resource for most dung beetle species. Competition for the trophic resource is common among the subfamily Scarabaeinae showing different habits depending on the quantity and quality of food available. In this study, we evaluated the dung of six species of mammal native to Chiapas (Mexico) as attractants for sampling dung beetles. The six species have different feeding habits (carnivores, herbivores and omnivores) and the feces used were obtained from Zoo animals fed a standard diet. Sampling efficiency was over 99% for each of the attractants. Tapirus bairdii feces attracted the highest abundance, while Canis latrans attracted the highest richness and diversity was higher in Procyon lotor. The captured species showed no affinity for a specific attractant, and differences in richness, abundance, diversity, and species composition between baits were largely non-significant. These results suggest that when food availability is high, Scarabaeinae assemblages maintain very abundant populations with generalists feeding habits. However, other aspects such as the quality and quantity (volume) of the food may be important when choosing a resource. Hence, the use of different types of attractants that meet these characteristics offers the possibility of improving results in the monitoring of dung beetle communities in tropical forests, allowing the capture of those inconspicuous or rare species that inhabit the landscape. [ABSTRACT FROM AUTHOR]

India's growing role as a maritime powerhouse beckons unprecedented opportunities and challenges. The present mode of maritime governance characterised by the outdated role of generalists, particularly the Indian Administrative Service (IAS), is nothing more than an unfaded representation of a colonial stopgap arrangement with no scientific substance per se. Irrespective of an ideation that took place in 2014, the Indian Maritime Service (IMS) as a technocratic cadre for maritime administration never came to fruition. The commentary builds a rationale for IMS as a non-uniformed branch of specialists in view of the highly technical frontiers of civilian maritime domain, which is left in the hands of generalists. It concludes with the requirement of recalibrating the civil services with sub-specialist credentials to enhance the Indian maritime trajectories. [ABSTRACT FROM AUTHOR]

Aim: There is ongoing debate regarding the extent to which body size is selected by the environment. To address this issue, we assessed how thermo-oxygenic conditions select body size of rotifer species composing a regional species pool. Location: Approximately 600 different water bodies in Sweden. Taxon: Rotifers (188 species). Methods: Data were acquired from previously published studies. For the environmental parameters, we conducted principal component analysis (PCA) to recognize the pattern among the species-specific thermal and oxygenic preferences of rotifers of different ecology. We assigned a standard body length to each species. We performed phylogenetically correlated analyses to evaluate the relationships between body length and the parameters that were selected as PCA drivers. Results: Thermal and oxygenic tolerance ranges, designated by the differences between the minimum and maximum of species occurrence, were grouped separately from the optima designated by the conditions referring to the highest species abundance, according to PC1 versus PC2. The parameters representing temperature and oxygen occupied opposite positions on the PC2 axis. Body size selection was driven by both temperature and oxygen, but the cues for this selection differed; species with higher thermal optima were smaller, while species with wider oxygen tolerance ranges were larger. Main conclusion: The body sizes of rotifer species are filtered by both thermal and oxygenic conditions. Selection is driven by tolerance ranges and optima. Oxygenic conditions are as important as thermal conditions in body size selection within a species assemblage. [ABSTRACT FROM AUTHOR]

Background: Landfills are a major subsidy for some animals, with implications for their life history and demography. Gulls feed extensively on food from landfills and closures are expected to have ecological consequences, but how this influences movement ecology is virtually unknown. Methods: We used GPS-tracking to quantify foraging behaviour and habitat choice of lesser black-backed gulls (Larus fuscus) breeding at two colonies before and after closure of two nearby landfills. Results: Following closure, gulls from both colonies travelled further and for longer to forage. Gulls also changed habitat selection, although this differed by colony - birds from one colony shifted to agricultural habitats, while at the other, increased their use of urban areas. These behavioural responses had no effect on adult body condition but hint at potential direct effects of higher foraging costs and indirect impacts by shifting to new habitats. Conclusions: Our results demonstrate how landfill availability influences gull foraging movements and habitat selection. We also emphasize the value of biologging to detect rapid behavioural responses in contrast to more conventional demographic approaches, which is especially important for animals that spend the majority of their lives away from direct observation. [ABSTRACT FROM AUTHOR]