Land-use intensity influences European tetrapod food webs.

Land use intensification favours particular trophic groups which can induce architectural changes in food webs. These changes can impact ecosystem functions, services, stability and resilience. However, the imprint of land management intensity on food-web architecture has rarely been characterized across large spatial extent and various land uses. We investigated the influence of land management intensity on six facets of food-web architecture, namely apex and basal species proportions, connectance, omnivory, trophic chain lengths and compartmentalization, for 67,051 European terrestrial vertebrate communities. We also assessed the dependency of this influence of intensification on land use and climate. In addition to more commonly considered climatic factors, the architecture of food webs was notably influenced by land use and management intensity. Intensification tended to strongly lower the proportion of apex predators consistently across contexts. In general, intensification also tended to lower proportions of basal species, favoured mesopredators, decreased food webs compartmentalization whereas it increased their connectance. However, the response of food webs to intensification was different for some contexts. Intensification sharply decreased connectance in Mediterranean and Alpine settlements, and it increased basal tetrapod proportions and compartmentalization in Mediterranean forest and Atlantic croplands. Besides, intensive urbanization especially favoured longer trophic chains and lower omnivory. By favouring mesopredators in most contexts, intensification could undermine basal tetrapods, the cascading effects of which need to be assessed. Our results support the importance of protecting top predators where possible and raise questions about the long-term stability of food webs in the face of human-induced pressures.

How interacting anthropogenic pressures alter the plasticity of breeding time in two common songbirds.

Phenological adjustment is the first line of adaptive response of vertebrates when seasonality is disrupted by climate change. The prevailing response is to reproduce earlier in warmer springs, but habitat changes, such as forest degradation, are expected to affect phenological plasticity, for example, due to loss of reliability of environmental cues used by organisms to time reproduction. Relying on a two-decade, country-level capture-based monitoring of common songbirds' reproduction, we investigated how habitat anthropization, here characterized by the rural-urban and forest-farmland gradients, affected the average phenology and plasticity to local temperature in two common species, the great tit Parus major and the blue tit Cyanistes caeruleus. We built a hierarchical model that simultaneously estimated fledging phenology and its response to spring temperatures based on the changes in the proportion of juveniles captured over the breeding season. Both species fledge earlier in warmer sites (blue tit: 2.94 days/°C, great tit: 3.83 days/°C), in warmer springs (blue tit: 2.49 days/°C, great tit: 2.75 days/°C) and in most urbanized habitats (4 days for blue tit and 2 days for great tit). The slope of the reaction norm of fledging phenology to spring temperature varied across sites in both species, but this variation was explained by habitat anthropization only in the deciduous forest specialist, the blue tit. In this species, the responses to spring temperature were shallower in agricultural landscapes and slightly steeper in more urban areas. Habitat anthropization did not explain variation in the slope of the reaction norm in the habitat-generalist species (great tit), for which mean fledgling phenology and plasticity were correlated (i.e., steeper response in later sites). The effects of habitat change on phenological reaction norms provide another way through which combined environmental degradations may threaten populations' persistence, to an extent depending on species and on the changes in their prey phenology and abundance.

DNA damage as indicator of the environmental vulnerability of bats in Brazil's Caatinga drylands.

Brazil's Caatinga drylands is under extensive environmental deterioration, with 38% of its natural cover already lost. There is a need for a better understanding of the effects of such degradation on Caatinga's rich and singular biota. Bats form a large part of this biota, and are pointed as good bioindicators. Here, we used the micronucleus test -an easy-to-use, accessible and cost-effective in vivo approach- to detect DNA damage in cells from bats of different species and feeding habits in three protected areas in the Caatinga, comparing them with samples from an industrial sugarcane plantation. We hypothesized that environmental disturbance would reflect in DNA damage, with lower levels of damage in the less disturbed protected areas. The frequency of micronucleated cells differed significantly between sites and feeding habits (carnivores > insectivores > frugivores > nectarivores > hematophagous) but did not differ between sexes. Alarmingly, the highest levels of DNA damage were in two strictly protected areas (Seridó and Raso da Catarina Ecological Stations). Glossophaga and Anoura were the genera with more damaged cells, and had, respectively, 1.48 and 3.53 times more micronucleated cells (average of 19.33 and 22.67 cells, respectively) than individuals from the same genera from the area with least damaged cells (average of 7.80 and 5.00 cells, respectively). Our analysis is a warning call for an in-depth investigation on the effects of both genotoxic contamination and environmental stressors on bats and other species in Brazil's Caatinga, including the role that historical human-induced processes -like the intense use of agrochemicals- may have had in the region.

Anthropization level of Lascaux Cave microbiome shown by regional-scale comparisons of pristine and anthropized caves.

Limestone areas across the world develop karstic caves, which are populated by a wide range of macro- and microorganisms. Many of these caves display Paleolithic art or outstanding speleothems, and in the last century they have been subjected to anthropization due to touristic management and intense human frequentation. Despite their cultural importance and associated conservation issues, the impact of anthropization on cave biodiversity is not known. Here, we show that anthropization is associated with specific cave biota modifications. We compared diversity in four pristine caves, four anthropized show caves, and the iconic Lascaux Cave with even stronger anthropization. The predominant microbial higher taxa were the same in all caves, but the most anthropized cave (Lascaux) was unique as it differed from the eight others by a higher proportion of Bacteroidetes bacteria and the absence of Euryarchaeota and Woesearchaeota archaea. Anthropization resulted in lower diversity and altered community structure for bacteria and archaea on cave walls, especially in Lascaux, but with a more limited effect on microeukaryotes and arthropods. Our findings fill a key gap in our understanding of the response of karstic communities to anthropization, by revealing that tourism-related anthropization impacts on the prokaryotic microbiome rather than on eukaryotic residents, and that it shapes cave biota irrespective of cave natural features.

Anthropization in the coastal zone associated with Mexican mangroves (2005-2015).

The present work had the goal of assessing anthropization of mangroves in Mexico during the 2005-2015 period. We modified the Relative Integrated Anthropization Index (INRA in its Spanish acronym) method developed by Martínez-Dueñaz (Intrópica: 37-46, 2010) for its use in Mexico. The maps of the Mexican Mangrove Monitoring System of the National Commission for the Knowledge and Use of Biodiversity (SMMM CONABIO in its Spanish acronym) for the years 2005, 2010, and 2015 were classified into 10 land use categories and 21 subcategories. The relative anthropization values were obtained for subcategories and classes in the input maps through consultation with mangrove specialists and the results were integrated to calculate the INRA values in 500 m2 units. Our results showed an increase in the surface of most anthropic categories and a sustained increment of the mean INRA values at the national level.

Human activities and densities shape insecticide resistance distribution and dynamics in the virus-vector Culex pipiens mosquitoes from Morocco.

BACKGROUND: Mosquitoes of the Culex pipiens complex are widely distributed vectors for several arboviruses affecting humans. Consequently, their populations have long been controlled using insecticides, in response to which different resistance mechanisms have been selected. Moreover, their ecological preferences and broad adaptability allow C. pipiens mosquitoes to breed in highly polluted water bodies where they are exposed to many residuals from anthropogenic activities. It has been observed for several mosquito species that anthropization (in particular urbanization and agricultural lands) can lead to increased exposure to insecticides and thus to increased resistance. The main objective of the present study was to investigate whether and how urbanization and/or agricultural lands had a similar impact on C. pipiens resistance to insecticides in Morocco. METHODS: Breeding sites were sampled along several transects in four regions around major Moroccan cities, following gradients of decreasing anthropization. The imprint of anthropogenic activities was evaluated around each site as the percentage of areas classified in three categories: urban, agricultural and natural. We then assessed the frequencies of four known resistance alleles in these samples and followed their dynamics in five urban breeding sites over 4 years. RESULTS: The distribution of resistance alleles revealed a strong impact of anthropization, in both agricultural and urbanized lands, although different between resistance mutations and between Moroccan regions; we did not find any clear trend in the dynamics of these resistance alleles during the survey. CONCLUSIONS: Our study provides further evidence for the role of anthropic activities in the selection and maintenance of mutations selected for resistance to insecticides in mosquitoes. The consequences are worrying as this could decrease vector control capacities and thus result in epizootic and epidemic outbreaks. Consequently, concerted and integrated disease control strategies must be designed that include better management regarding the consequences of our activities.

The human touch: a meta-analysis of anthropogenic effects on plant-pollinator interaction networks.

Background: Anthropogenic activities significantly impact natural ecosystems, leading to alterations in plant and pollinator diversity and abundance. These changes often result in shifts within interacting communities, potentially reshaping the structure of plant-pollinator interaction networks. Given the escalating human footprint on habitats, evaluating the response of these networks to anthropization is critical for devising effective conservation and management strategies. Methods: We conducted a comprehensive review of the plant-pollinator network literature to assess the impact of anthropization on network structure. We assessed network metrics such as nestedness measure based on overlap and decreasing fills (NODF), network specialization (H2'), connectance (C), and modularity (Q) to understand structural changes. Employing a meta-analytical approach, we examined how anthropization activities, such as deforestation, urbanization, habitat fragmentation, agriculture, intentional fires and livestock farming, affect both plant and pollinator richness. Results: We generated a dataset for various metrics of network structure and 36 effect sizes for the meta-analysis, from 38 articles published between 2010 and 2023. Studies assessing the impact of agriculture and fragmentation were well-represented, comprising 68.4% of all studies, with networks involving interacting insects being the most studied taxa. Agriculture and fragmentation reduce nestedness and increase specialization in plant-pollinator networks, while modularity and connectance are mostly not affected. Although our meta-analysis suggests that anthropization decreases richness for both plants and pollinators, there was substantial heterogeneity in this regard among the evaluated studies. The meta-regression analyses helped us determine that the habitat fragment size where the studies were conducted was the primary variable contributing to such heterogeneity. Conclusions: The analysis of human impacts on plant-pollinator networks showed varied effects worldwide. Responses differed among network metrics, signaling nuanced impacts on structure. Activities like agriculture and fragmentation significantly changed ecosystems, reducing species richness in both pollinators and plants, highlighting network vulnerability. Regional differences stressed the need for tailored conservation. Despite insights, more research is crucial for a complete understanding of these ecological relationships.

Seasonal Hair Glucocorticoid Fluctuations in Wild Mice (Phyllotis darwini) within a Semi-Arid Landscape in North-Central Chile.

Mammals in drylands face environmental challenges exacerbated by climate change. Currently, human activity significantly impacts these environments, and its effects on the energy demands experienced by individuals have not yet been determined. Energy demand in organisms is managed through elevations in glucocorticoid levels, which also vary with developmental and health states. Here, we assessed how anthropization, individual characteristics, and seasonality influence hair glucocorticoid concentration in the Darwin's leaf-eared mouse (Phyllotis darwini) inhabiting two areas with contrasting anthropogenic intervention in a semi-arid ecosystem of northern Chile. Hair samples were collected (n = 199) to quantify hair corticosterone concentration (HCC) using enzyme immunoassays; additionally, sex, body condition, and ectoparasite load were recorded. There were no differences in HCC between anthropized areas and areas protected from human disturbance; however, higher concentrations were recorded in females, and seasonal fluctuations were experienced by males. The results indicate that animals inhabiting semi-arid ecosystems are differentially stressed depending on their sex. Additionally, sex and season have a greater impact on corticosterone concentration than anthropogenic perturbation, possibly including temporal factors, precipitation, and primary production. The influence of sex and seasonality on HCC in P. darwini make it necessary to include these variables in future stress assessments of this species.

Spatio-temporal variation of biting flies, Stomoxys spp. (Diptera: Muscidae), along a man-made disturbance gradient, from primary forest to the city of Makokou (North-East, Gabon).

Understanding the pattern of abundance of vector populations is important to control the potential of transmission of associated pathogens. The pattern of abundance of Stomoxys Geoffroy, an ubiquitous blood-sucking fly, is poorly known in tropical Africa. In this study, we investigated the spatio-temporal pattern of abundance of the Stomoxys genus along a gradient of man-made disturbance in north-eastern Gabon. Three sites (one in primary forest, one in secondary forest and one in a man-made environment) were monitored during 13 months using Vavoua traps. Seven species and subspecies were found to live in sympatry, but with distinct patterns of abundance with respect to space and time. The most abundant species was Stomoxys transvittatus Villeneuve, whereas the rarest species was S. xanthomelas Roubaud. Stomoxys calcitrans Linné was preferentially found in man-made environments, whereas S. xanthomelas was preferentially found in primary forest. Stomoxys abundance was the greatest in secondary forest, then in man-made environments and finally in primary forest. A seasonal variation in Stomoxys abundance was also found. In conclusion, forest degradation and deforestation are likely both to favour the concentration of populations of Stomoxys, and to change the specific composition of the Stomoxys community.

Antimicrobial-Resistant Bacteria Carriage in Rodents According to Habitat Anthropization.

It is increasingly suggested that the dynamics of antimicrobial-resistant bacteria in the wild are mostly anthropogenically driven, but the spatial and temporal scales at which these phenomena occur in landscapes are only partially understood. Here, we explore this topic by studying antimicrobial resistance in the commensal bacteria from micromammals sampled at 12 sites from a large heterogenous landscape (the Carmargue area, Rhone Delta) along a gradient of anthropization: natural reserves, rural areas, towns, and sewage-water treatment plants. There was a positive relationship between the frequency of antimicrobial-resistant bacteria and the level of habitat anthropization. Although low, antimicrobial resistance was also present in natural reserves, even in the oldest one, founded in 1954. This study is one of the first to support the idea that rodents in human-altered habitats are important components of the environmental pool of resistance to clinically relevant antimicrobials and also that a "One Health" approach is required to assess issues related to antimicrobial resistance dynamics in anthropized landscapes.

Sarcosaprophagous Muscid Fly (Diptera: Muscidae) Assemblages Along an Anthropized Gradient in the Humid Chaco Ecoregion, Chaco Province, Argentina.

Deforestation, agriculture, farmyard animal husbandry, and urbanization are known to be the main causes of biodiversity loss and habitat fragmentation. The present study evaluated the role of anthropization in modulating Muscidae (Diptera) assemblages in the Humid Chaco ecoregion of Argentina, by testing the biotic homogenization and intermediate disturbance hypotheses. The study focused on natural, rural, and urban habitats in San Lorenzo Department, Chaco Province, where sarcosaprophagous muscid flies were surveyed. A total of 1,343 muscid flies were captured and identified to 7 genera and 24 species and morphospecies. We observed the effect of anthropization on the structuring of the assemblages and the presence of exotic species associated with human activity resulting from biotic homogenization. The highest abundance was recorded in the urban habitat, while the highest species richness and diversity (Shannon-Wienner and Hill's numbers) were found in the rural habitat, supporting the intermediate disturbance hypothesis. Several species are classified as indicators of habitat as well as according to their index of synanthropy. Our results provide valuable information about the use of sarcosaprophagous muscids as indicators of disturbance of natural habitats and about possible health risks related to this family of Calyptratae flies previously unsurveyed in northeastern Argentina. This information could be used in the ecological, agronomy, sanitary, and forensic fields.

Hogs sleep like logs: Wild boars reduce the risk of anthropic disturbance by adjusting where they rest.

Many animals living in anthropized landscapes try to avoid encountering people by being active at night. By doing so, however, they risk being disturbed while at rest during the day. To mitigate this risk, diurnally resting species may be highly selective about where they rest. Here, we used GPS and activity sensors to study how wild boars (Sus scrofa) might adjust their resting site selection and revisitation patterns to the risk of disturbance by people. We evaluated the probability of daytime relocation to assess the efficacy of wild boars' resting strategy in reducing the risk of human encounter while at rest. We attempted to identify the cause of some relocations using audio recordings. Generally, we found that wild boars did not specifically avoid resting near villages or roads, that is, where the risk of encountering people is higher, if they could find sites with suitable vegetation cover. The risk of disturbance by people was low, even near villages. Resting sites located close to villages were visited more repeatedly than those located further away, suggesting that focusing on a few familiar and quiet resting sites was a successful strategy for resting undisturbed in an anthropized landscape.

Polycyclic aromatic hydrocarbon record in an urban secondary carbonate deposit over the last three centuries (Paris, France).

Preserving water resources and limiting pollution are central environmental issues in the current context of intense anthropization. Among organic pollutants, polycyclic aromatic hydrocarbons (PAHs) are commonly analysed as part of water quality assessments. After being emitted into the atmosphere, these persistent organic pollutants are deposited on the continental surface, where they are transported to the aquatic environment by run-off and infiltration waters. Mainly due to anthropogenic emissions, PAHs can therefore be considered as a proxy for human activities. Urban secondary carbonate deposits (USCDs), similar to cave speleothems, have recently been studied for their potential as natural archives of water quality. However, USCDs have never been used to trace water organic pollution and only a few studies on PAHs in speleothems are available. This study focuses on a well-dated USCD covering the last 300 years from the Great Aqueduct of Belleville (north-east of Paris, France). The aim is to determine the nature and variation of trapped organic compounds over time and to discuss their origin, transport, and link with changes in soil occupation due to human activities. To do so, high-resolution solid-phase UV fluorescence imaging analyses were combined with chemical analyses of PAHs and organic carbon carried out on low-weight samples. The results show that PAHs have been present in urban surface water for 300 years. Over the last few decades, a 7-fold increase is observed, accompanied by a change in the pollution source, enriched in high-molecular-weight PAHs, probably linked to urban dust. This study also reveals modes of transport directly influenced by changes in the soil occupation that are very different from those usually encountered in natural environments. This work thus paves the way for a better long-term understanding of the impact of human activity on the transfer of pollutants to sub-surface waters.

The specter of cholera in Libya and North Africa: Natural disasters and anthropization threaten human health during recent years.

Introduction: According to data from the World Health Organization (WHO), in the last year cholera has re-emerged in various areas of the planet, particularly in Africa. The resurgence of this disease is closely linked to poor hygiene, which is sometimes the result of wars or environmental disasters, as in Lebanon and Syria since autumn 2022 and today in Libya. Discussion: The spread of cholera is chiefly caused by the presence of contaminated water, in environments with inadequate hygiene and sanitation. Another cause, however, is the lack of access to adequate vaccination and treatment campaigns. Method: In this short paper, the authors highlight the possibility of a resurgence of epidemic cholera in Libya, especially in light of the consequences of the devastating cyclone Daniel and the simultaneous collapse of two dams upstream of the city of Derna. They also highlight the concern that cholera and other infectious diseases may also spread in Morocco, which was hit by a severe earthquake on 8 September last. The focus of the paper is the awareness that the spread of epidemic diseases is very often linked to human actions, which may trigger or exacerbate the effects of natural disasters. Conclusions: Since these events have devastating effects both on the environment and on people and their psychophysical balance, it is evident that we need to devote greater attention to the health of the planet, to which the health and survival of the human species is strictly and inextricably linked. Indeed, disasters related to phenomena of anthropization facilitate the spread of infectious diseases, placing a heavy burden on local and global health organizations and the health of entire populations. A change of course is therefore essential, in that human actions must be aimed at limiting rather than aggravating the spread of diseases.

Oxidative status in relation to blood parasite infections in house sparrows living along an urbanization gradient.

Living organisms are exposed to a wide range of substances - internal and external - which act like reactive oxygen species (ROS). Oxidative damage accurs when the balance between ROS and antioxidant defenses is altered. Urbanization and parasite infection are both important sources of ROS with different harmful effects on wildlife health, but the potential synergies between both factors are poorly known. Here, we analyse the oxidative stress of wild juvenile male house sparrows (Passer domesticus) along an urbanization gradient in relation to the infection status by three common blood parasites (Plasmodium, Haemoproteus and Leucocytozoon) and bird body condition. We analysed samples from 688 birds captured at 45 localities from southern Spain grouped into triplets including an urban, a rural and a natural habitat, with 15 localities per habitat type. We measured i) thiobarbituric acid reactive substances (TBARS) levels as indicator of the oxidative damage to lipids, and the activity of three antioxidant enzymes ii) glutathione peroxidase (GPx), iii) superoxide dismutase (SOD) and iv) glutathione reductase (GR) as indicators of bird's antioxidant capacity. Birds infected with Haemoproteus and urban birds showed significantly and marginally higher levels of TBARS than uninfected and rural birds, respectively. The relationship between TBARS and body condition is different regarding the infection status (significative) and habitat (marginally significant) being negative for Haemoproteus infected and urban birds but positive for uninfected and non-urban birds. The antioxidant activity was significantly lower in Plasmodium infected birds but marginally higher in Leucocytozoon infected birds than in uninfected ones. Individuals with higher body condition had higher GPx and SOD activity in relation to a lower GR activity. Overall, these results suggest that blood parasites infections and urbanization affect the oxidative status of wild birds and highlight the role of bird's body condition on the regulation of the oxidative stress status.

Impacts of land use change on native plant-butterfly interaction networks from central Mexico.

Background: Land use change is a key catalyst of global biodiversity loss and ecosystem degradation. Deforestation and conversion of natural habitats to agricultural or urban areas can profoundly disrupt plant-flower visitor interactions by altering their abundances and distribution. Yet, specific studies analyzing the effects of land use change on the structure of networks of the interactions between particular groups of flower visitors and their plants are still scarce. Here, we aimed to analyze how converting native habitats affects the species composition of butterfly communities and their plants, and whether this, in turn, leads to changes in the structure of interaction networks in the modified habitats. Methods: We performed bi-monthly censuses for a year to record plant-butterfly interactions and assess species diversity across three habitat types, reflecting a land-use change gradient. From original native juniper forest to urban and agricultural zones in central Mexico, one site per land use type was surveyed. Interactions were summarized in matrices on which we calculated network descriptors: connectance, nestedness and modularity. Results: We found highest butterfly diversity in native forest, with the most unique species (i.e., species not shared with the other two sites). Agricultural and urban sites had similar diversity, yet the urban site featured more unique species. The plant species richness was highest in the urban site, and the native forest site had the lowest plant species richness, with most of the plants being unique to this site. Butterfly and plant compositions contrasted most between native forest and modified sites. Network analysis showed differences between sites in the mean number of links and interactions. The urban network surpassed agriculture and native forest networks in links, while the native forest network had more interactions than the agriculture and urban networks. Native plants had more interactions than alien species. All networks exhibited low connectance and significant nestedness and modularity, with the urban network featuring the most modules (i.e., 10 modules). Conclusions: Converting native habitats to urban or agricultural areas reshapes species composition, diversity and interaction network structure for butterfly communities and plants. The urban network showed more links and modules, suggesting intricate urban ecosystems due to diverse species, enhanced resources, and ecological niches encouraging interactions and coexistence. These findings emphasize the impacts of land use change on plant-butterfly interactions and the structure of their interaction networks.

Dark-zone alterations expand throughout Paleolithic Lascaux Cave despite spatial heterogeneity of the cave microbiome.

BACKGROUND: Cave anthropization related to rock art tourism can lead to cave microbiota imbalance and microbial alterations threatening Paleolithic artwork, but the underpinning microbial changes are poorly understood. Caves can be microbiologically heterogeneous and certain rock wall alterations may develop in different rooms despite probable spatial heterogeneity of the cave microbiome, suggesting that a same surface alteration might involve a subset of cosmopolitan taxa widespread in each cave room. We tested this hypothesis in Lascaux, by comparing recent alterations (dark zones) and nearby unmarked surfaces in nine locations within the cave. RESULTS: Illumina MiSeq metabarcoding of unmarked surfaces confirmed microbiome heterogeneity of the cave. Against this background, the microbial communities of unmarked and altered surfaces differed at each location. The use of a decision matrix showed that microbiota changes in relation to dark zone formation could differ according to location, but dark zones from different locations displayed microbial similarities. Thus, dark zones harbor bacterial and fungal taxa that are cosmopolitan at the scale of Lascaux, as well as dark zone-specific taxa present (i) at all locations in the cave (i.e. the six bacterial genera Microbacterium, Actinophytocola, Lactobacillus, Bosea, Neochlamydia and Tsukamurella) or (ii) only at particular locations within Lascaux. Scanning electron microscopy observations and most qPCR data evidenced microbial proliferation in dark zones. CONCLUSION: Findings point to the proliferation of different types of taxa in dark zones, i.e. Lascaux-cosmopolitan bacteria and fungi, dark zone-specific bacteria present at all locations, and dark zone-specific bacteria and fungi present at certain locations only. This probably explains why dark zones could form in various areas of the cave and suggests that the spread of these alterations might continue according to the area of distribution of key widespread taxa.

Human Settlement and Landscape Anthropization of Remote Oceanic Islands: A Comparison between Rapa Nui (Pacific Ocean) and the Azores (Atlantic Ocean).

The flora and vegetation of oceanic islands have been deeply affected by human settlement and further landscape modifications during prehistoric and historical times. The study of these transformations is of interest not only for understanding how current island biotas and ecological communities have been shaped but also for informing biodiversity and ecosystem conservation. This paper compares two oceanic insular entities of disparate geographical, environmental, biological, historical and cultural characteristics-Rapa Nui (Pacific Ocean) and the Azores Islands (Atlantic Ocean)-in terms of human settlement and further landscape anthropization. The similarities and differences between these islands/archipelagos are discussed considering their permanent colonization, the possibility of earlier settlements, the removal of the original forests and the further landscape transformations leading to either full floristic/vegetational degradation (Rapa Nui) or major replacement (Azores). This comparison uses evidence from varied disciplines, notably paleoecology, archaeology, anthropology and history, to obtain a holistic view of the development of the respective socioecological systems from a human ecodynamic perspective. The most relevant issues still to be resolved are identified and some prospects for future research are suggested. The cases of Rapa Nui and Azores Islands may help set a conceptual basis for ocean-wide global comparisons among oceanic islands/archipelagos.

Microbiome Analysis of New, Insidious Cave Wall Alterations in the Apse of Lascaux Cave.

Lascaux Cave is a UNESCO site that was closed to the public following wall surface alterations. Most black stains that had formed on wall surface are stable or receding, but a new type of alteration visually quite different (termed dark zones) developed in Lascaux's Apse room in the last 15 years. Here, we tested the hypothesis that dark zones displayed a different microbial community than black stains previously documented in the same room, using metabarcoding (MiSeq sequencing). Indeed, dark zones, black stains and neighboring unstained parts displayed distinct microbial communities. However, similarly to what was observed in black stains, pigmented fungi such as Ochroconis (now Scolecobasidium) were more abundant and the bacteria Pseudomonas less abundant in dark zones than in unstained parts. The collembola Folsomia candida, which can disseminate microorganisms involved in black stain development, was also present on dark zones. Illumina sequencing evidenced Ochroconis (Scolecobasidium) in all collembola samples from dark zones, as in collembola from black stains. This study shows that the microbial properties of dark zones are peculiar, yet dark zones display a number of microbial resemblances with black stains, which suggests a possible role of collembola in promoting these two types of microbial alterations on wall surfaces.

Microbial ecology of tourist Paleolithic caves.

Microorganisms colonize caves extensively, and in caves open for tourism they may cause alterations on wall surfaces. This is a major concern in caves displaying Paleolithic art, which is usually fragile and may be irremediably damaged by microbial alterations. Therefore, many caves were closed for preservation purposes, e.g. Lascaux (France), Altamira (Spain), while others were never opened to the public to avoid microbial contamination, e.g. Chauvet Cave (France), etc. The recent development of high-throughput sequencing technologies allowed several descriptions of cave microbial diversity and prompted the writing of this review, which focuses on the cave microbiome for the three domains of life (Bacteria, Archaea, microeukaryotes), the impact of tourism-related anthropization on microorganisms in Paleolithic caves, and the development of microbial alterations on the walls of these caves. This review shows that the microbial phyla prevalent in pristine caves are similar to those evidenced in water, soil, plant and metazoan microbiomes, but specificities at lower taxonomic levels remain to be clarified. Most of the data relates to Bacteria and Fungi, while other microeukaryotes and Archaea are poorly documented. Tourism may cause shifts in the microbiota of Paleolithic caves, but larger-scale investigation are required as these shifts may differ from one cave to the next. Finally, different types of alterations can occur in caves, especially in Paleolithic caves. Many microorganisms potentially involved have been identified, but diversity analyses of these alterations have not always included a comparison with neighboring unaltered zones as controls, making such associations uncertain. It is expected that omics technologies will also allow a better understanding of the functional diversities of the cave microbiome. This will be needed to decipher microbiome dynamics in response to touristic frequentation, to guide cave management, and to identify the most appropriate reclamation approaches to mitigate microbial alterations in tourist Paleolithic caves.