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Climate change is having an increasingly rapid impact on ecosystems and particularly on the issue of water resources. The Internet of Things and communication technologies have now reached a level of maturity that allows sensors to be deployed more easily on sites to monitor them. The communicating node based on LoRaWAN technology presented in this article is open and allows the interfacing of numerous sensors for designing long-term environmental monitoring systems of isolated sites. The data integration in the cloud is ensured by a workflow driving the storage and indexing of data, allowing a simple and efficient use of the data for different users (scientists, administration, citizens) through specific dashboards and extractions. This article presents this infrastructure through environmental monitoring use cases related to water resources. [ABSTRACT FROM AUTHOR]

Riverbank erosion is an essential morphodynamic process for the improvement of river health and the ecohydrogeomorphological functioning of alluvial rivers. Lateral channel dynamics and sediment supply caused by bank erosion largely create and maintain heterogeneous in-channel habitats for fauna and aquatic or riparian plant species. However, humans very early started to stabilize riverbanks in order to favour navigation or to prevent valuable land and infrastructures close to the channel from eroding. During the 20th century, bank protection works such as riprap considerably increased and blocked lateral channel erosion, causing a loss of local sediment supply, which in turn resulted in a decrease in local bedload transport and channel incision. The aim of the article is to evaluate to what extent riprap removal may be an efficient restoration measure in terms of the reactivation of bank erosion and the replenishment of the local bedload in gravel-bed floodplain rivers with a sufficient amount of freedom space. An experimental in situ restoration approach was chosen. First, riprap was removed at two geomorphologically contrasting sites on the Allier River, France. Second, bank retreat was monitored, and the volumes eroded were quantified using photogrammetric and LiDAR surveys. Third, in the case of post-restoration bank erosion, grain size and morphological channel evolution analyses were carried out. Our results suggested that the removal of riprap is an effective measure for certain but not all channelized floodplain reaches. The geomorphological and sedimentary contexts are two criteria that should be considered when selecting sites for restoration. Thus, this study helps river managers to better target the criteria to be taken into account for the selection of sites with high potential for the restoration of lateral channel dynamics. [ABSTRACT FROM AUTHOR]

Springs are abundant and present worldwide and are among the most threatened ecosystems on Earth. The main aim of this study was to evaluate the biodiversity of seventy-nine (79) mineral saline springs situated in the French Massif Central, focusing on the species richness and the estimated richness and also on the diatom community composition. The influence of physical and chemical factors on both richness and communities was analyzed in order to have a better knowledge of the diatom ecological preferences and identify species typical of saline springs. Since December 2014, an on-going inventory of mineral springs has been in progress. For each spring, physical and chemical characteristics were measured, and benthic diatoms were sampled. The richness was the lowest in the springs presenting a man-made construction around the emergence. In the other springs, the highest richness was associated with the lowest lithium, sodium, total dissolved solid concentrations, and conductivity. Mineralization and some ions (bromine, calcium, chloride, fluoride, lithium, potassium, and sodium) were found to be the most critical drivers of diatom community composition. Some diatom species were typical of specific abiotic conditions, such as Navicula sanctamargaritae, which was associated with the highest potassium concentration. These species could appear as bio-indicators of these conditions. [ABSTRACT FROM AUTHOR]

Light and scanning electron microscope observations on the genus Fontina gen. nov. from a thermo-mineral spring of the Massif Central (France) are presented. Based on morphology, the new genus shows features that have not been described previously, such as the stria pattern, interrupted at the valve face/mantle junction and composed of one long, slit-like areola on both valve face and mantle. Externally, areolae are closed by hymenes. Fontina arverna sp. nov. is described as the typus generis of Fontina. This new genus was compared with some similar freshwater genera such as Adlafia, Chamaepinnularia, Genkalia, Germainiella, Microfissurata and Nupela. So far, we are unable to establish an evolutionary link or cladistic association with currently known genera. The new genus is described from a sampling site characterized by high conductivity and high carbonate concentration, brackish conditions and whose water originates deep in the crust (high lithium concentration). [ABSTRACT FROM AUTHOR]

This study investigated and compared the diatom flora from thermo-mineral springs in Auvergne (France) and Sardinia (Italy). Samples were collected from rock/cobbles and fine sediments in 16 springs between January 2015 and March 2017. A total of 207 taxa (59 genera) were found. Multivariate analyses revealed significant differences in species composition and abundance among diatom assemblages both within each geographic region and between Auvergne and Sardinia (global R = 0.516; p = 0:002), suggesting the importance of local and climatic factors in species distribution. Based on abundance and common occurrence in multiple sites, some taxa can be considered more representative of springs in each region: Crenotia thermalis for Auvergne and Lemnicola exigua, Nitzschia amphibia, N. inconspicua and Rhopalodia operculata for Sardinia. pH, conductivity and HCO3– were the most significant environmental variables for diatom assemblages. Our results highlight the high heterogeneity of these spring systems. Future taxonomic insights can be useful to define the identity of some abundant and dominant taxa not identified at the species level in this study. Their identification is a crucial step for a more precise ecological characterization and comparison of these peculiar spring systems. [ABSTRACT FROM AUTHOR]

Populations of the riparian pioneer species Populus nigra L. which establish on alluvial bars within river channels modulate sediment dynamics and fluvial landforms. Dense cohorts of P. nigra have colonized gravel point bars along the channelized River Garonne, France, during the last 20 years and have enhanced the vertical, lateral and longitudinal development of the bars. For this period, the geomorphic characteristics of two wooded point bars on this laterally stable river are closely linked to the spatial distribution and intensity of establishment and resistance of different cohorts of P. nigra. Furthermore, P. nigra colonization dynamics were controlled by engineer effects of this same species. This relationship is illustrated by a significant correlation between key geomorphic and biological variables measured in situ and characterized with a set of four aerial photographs taken between 2000 and 2010. The development of wooded point bars, which are discrete biogeomorphic units, over the studied period, appear to result from a specific biogeomorphic positive feedback of matter aggregation and vegetation establishment related to sediment trapping and stabilization by pioneer engineer plants. We propose a conceptual model of biogeomorphic unit construction for channelized, lateral stable rivers. We consider the resultant biogeomorphic units as functional from an ecological point of view because P. nigra enhances at the cohort scale (i) its own inherent capacity to resist hydrogeomorphic disturbances, and (ii) its resilience capacity as a result of successful colonization, especially downstream of mature poplar stands. [ABSTRACT FROM AUTHOR]

Successful invasion is often due to a combination of species characteristics (or invasiveness) and habitat suitability (or invasibility). Our objective was to identify preferred habitats and suitable environmental conditions for the African tulip tree Spathodea campanulata (Bignoniaceae), one of the most invasive alien trees on the tropical island of French Polynesia (South Pacific Ocean), in relation to its distribution and photosynthesis capacity. Spathodea abundance and leaf chlorophyll fluorescence Fo', ETRmax, and Y(II) effective were examined in relation to topography and micro-climate along elevational transects between 140 m and 1,300 m. Results showed that Spathodea is (1) present up to 1,240 m with lowest maximum July-October (cool season) temperature of 9.4 °C and an average July-October temperature of 14.6 °C, (2) is able to colonize slope steepness of more than 45°, (3) is well represented in the elevational range of 140-540 m as well as in the native forests between 940 m and 1,040 m, suggesting a high threat for native and endemic plants species. Along one of the transects, in the elevation range of 541-940 m, Spathodea was under-represented, Chl fluorescence Fo' increased significantly while Y(II)effective decreased significantly supporting the hypothesis that this range is a non-preferred environment, probably due to microclimate conditions characterized by punctual air dryness. Among Spathodea plants surveyed along a wetter transect, Y(II)effective and ETRmax were comparable from low elevation to mid-high elevation indicating that the potential photosynthesis rate of Spathodea may be similar from sea level until mid-high elevation. Major infestations on the island of Tahiti were reported on the leeward (drier and urbanized) west coast, but Spathodea has also been recently found on the slopes of the windward (wetter) east coast. Chlorophyll fluorescence measurements indicate a high photosynthetic capacity among Spathodea in wet environments suggesting that Spathodea will become invasive across most of the island of Tahiti. [ABSTRACT FROM AUTHOR]

The development of the Neolithic way of life in the western Mediterranean during the sixth millennium cal. BC is the consequence of the spread of populations from the Near East after successive stages of cultural remodelling. Despite the clear contribution of the Near Eastern and Aegean Neolithic to the economic and technical changes that happened to the west, little is known here about their symbolic legacies, because of the scarcity of representations and ritual evidences associated to the earliest western Neolithic contexts. Excavations at the rock shelter of Pendimoun (southeastern France) yielded the first anthropomorphic stone sculpture from the western Mediterranean Neolithic (early sixth millennium cal. BC). Using both carving and painting techniques, it represents a realistic-looking human face and is a unique example within the western Mediterranean and European frameworks. After describing the shaping and colouring details of the mask, the authors here deal with its possible social significances and cultural connections. [ABSTRACT FROM PUBLISHER]

Polar regions are very sensitive to climate variability. Glacial environments, such as Spitsbergen, respond drastically to climate warming by the disintegration of ice masses, release of huge amounts of free water and rapid evolution of terrestrial landforms. Paraglacial studies have shown that sediment yield decreases with time following a relaxation curve. The study examines the effects of scaling on rhythms of deglaciation and sediment fluxes in a small catchment. It appears that the paraglacial sequence, known as a morphogenic crisis, could be affected by internal small threshold events which are able to mobilize large quantities of sediment. It means that, at small scale, the curve profile is more irregular than suggested by large-scale models. [ABSTRACT FROM AUTHOR]

A floristic survey was performed on a temporary pond, "Laqui du Seignavoux", situated in the Mont-Dore massif of the French Massif Central, between 2017 and 2019. Except in 2017, each year, we performed four sampling campaigns from April/May to December. Water samples and diatoms were collected. The temporary pond evolved from a poorly mineralized ecosystem due to snow, inducing oligotrophic and oligosaprobic water, well oxygenated in spring, to a more mineralized, less oxygenated, eutrophic–hypereutrophic, and polysaprobic environment in summer. This change in abiotic conditions was found to be linked to the presence of cattle, beginning in May, that trample and excrete in the pond, leading to higher ammonium and nitrate concentrations. During this period, the dominant species were Pinnularia sp., Nitzschia palea, and Nitzschia palea var. tenuirostris. In spring and winter, different species of Eunotia dominated the community such as Eunotia pseudogroenlandica. Finally, light microscopy (LM) and scanning electron microscopy (SEM) observations on a new species of the genus Pinnularia from the temporary pond are presented and the ecological preferences are discussed. [ABSTRACT FROM AUTHOR]

The present study provides the first quantitative assessment of the deteriorative impact of forest clearance on susceptible sandstone masonries. At Ta Keo, a 1000 yr-old temple cleared of the Angkor forest in the early 20th century, GIS-based analysis of historic imagery indicates an average ten-fold increase in stone loss rates (0.2 instead of 0.02% per year). This accelerated decay is assigned to the climatic stress provoked by the exposure of fragile ornamented sandstones to the harsh impact of tropical sunshine and monsoon rains. Comparative climate monitoring with the Beng Mealea temple, still located in a forested environment, suggests a three-fold post-clearance increase in daily temperature and humidity ranges, which is conducive to enhanced swelling-shrinking movements responsible for accelerated sandstone contour scaling. Comparative visual assessment based on a customised 7-point scale of mechanical weathering confirms the protective role of canopy, with 79% of decorative motifs still almost free of mechanical weathering in the forest (against 7% at the cleared site). Disruption of archaeological structures by roots of individual trees can be locally observed at Angkor, but this does not negate the dominant overall buffering function of the forest cover. At Angkor and other cultural heritage sites, this bioprotective 'umbrella effect' should be considered as a valuable ecosystem service to be taken into account when defining and implementing strategies of sustainable management. [ABSTRACT FROM AUTHOR]