Priorities and gaps in Mediterranean bat research evidence: a systematic review for the early twenty-first century

Bat conservation is one of the top global concerns for research today; however, conservation efforts may still be limited and impotent due to inadequacy and scarcity of data. Hence, identifying research trends, threatening factors, species status, and geographical priorities is an essential tool for future conservation, protection and prioritization. Here we conduct a comprehensive systematic review to identify current research priorities, trends, general patterns and gaps regarding Mediterranean bat researches. A total of 97 studies were found in the years spanning between 2000 and 2021. There were 18 studies with sufficient data for qualitative statistical analysis to investigate the impact of different habitat and land managements on bat activity and species richness. A yearly average of 4.6 articles were published, with a slight increase post-2010. Out of 61 identified species, 21% of species are threatened. Approximately, 65% of studieswere conducted in the Mediterranean European region, primarily in Spain (29%), Italy (15.5%), and Portugal (10.3%), largely focusing on forest habitats (38%). We found that Mediterranean bat species received uneven research attention, with only 15% of research allocated to threatened bats. Around half of the studies focused on the following bat species; Pipistrellus pipistrellus, Pipistrellus kuhlii, Miniopterus schreibersii, Rhinolophus hipposideros, Pipistrellus pygmaeus, Myotis myotis, and Rhinolophus ferrumequinum. Our statistical analysis showed that riparian areas had higher bat activity than forest and agriculture areas. Bat population responded positively to forest management and organic agriculture practices. To reduce future research misalignment between current local research status and future global conservation priorities, we strongly advocate for urgent and additional collaborative efforts to target under-researched species and areas. Finally, our review will provide a general overview and an objective synthesis on the current status of bats in the Mediterranean and serve as a baseline for further effective research

Seasonal variation of mercury concentration of ancient olive groves of Lebanon

This study investigates the seasonality of the mercury (Hg) concentration of olive tree foliage, an iconic tree of the Mediterranean basin. Hg concentrations of foliage, stems, soil surface, and litter were analyzed on a monthly basis in ancient olive trees growing in two groves in Lebanon, Bchaaleh and Kawkaba (1300 and 672 m a.s.l. respectively). A significantly lower concentration was registered in stems (∼7–9 ng g−1) in comparison to foliage (∼35–48 ng g−1) in both sites, with the highest foliage Hg concentration in late winter–early spring and the lowest in summer. It is noteworthy that olive fruits also have low Hg concentrations (∼7–11 ng g−1). The soil has the highest Hg content (∼62–129 ng g−1) likely inherited through the cumulated litter biomass (∼63–76 ng g−1). A good covariation observed between our foliage Hg time series analysis and those of atmospheric Hg concentrations available for southern Italy in the western Mediterranean basin confirms that mercury pollution can be studied through olive trees. Spring sampling is recommended if the objective is to assess the trees' susceptibility to Hg uptake. Our study draws an adequate baseline for the eastern Mediterranean and the region with similar climatic inventories on Hg vegetation uptake, in addition to being a baseline to new studies on olive trees in the Mediterranean to reconstruct regional Hg pollution concentrations in the past and present.</p

Bats of Sicily: historical evidence, current knowledge, research biases and trends

Insular bat communities are a preeminent conservation taxon due to their ecological role and intriguing and unique species composition. Sicily is the largest island in the Mediterranean. However, research on Sicilian bats is still scattered, with substantial information being overlooked. Here we present a systematic review of all available bibliographic information from 1810 to 2022, including grey literature, archives, and peer-reviewed publications. The analyses of bibliographic sources permitted us to evaluate the status of research on bats using the Bat Research Efficiency (BRE) and Species-Research Effort Allocation (SREA) metrics. A total of 81 documents were obtained. Since 1955, an average of 1.2 contributions have been issued per year. Over half of the documents are in Italian. The studies are primarily conducted in north-western (40%) and south-eastern (28%) Sicily, mainly in the provinces of Palermo and Siracusa. Most of the contributions concern “Species records” (61%) and “Ecology” (21%). There were 28 species reported, but a significant bias exists towards Myotis myotis, Miniopterus schreibersii, Rhinolophus ferrumequinum, Myotis capaccinii, and Rhinolophus euryale. Around 31.5% of the studies focused on threatened species, while 68.5% concentrated on non-threatened species, with an overall preference for cave-dwelling species. Yet, SREA analysis demonstrates a lack of research efforts for all species. We encourage the use of a multidisciplinary approach towards under-studied species while covering geographical gaps and increasing public awareness of the functional role of bats in natural ecosystems. Cover Image: credits Saxifraga - Rudmer Zwerve

Spectrocolorimetric interpretation of sedimentary dynamics: The new "Q7/4 diagram"

International audienceColour is a fundamental property of sediment and is often used for lithographic description to determine sedimentological structures, facies etc. However, the sedimentary information contained in this parameter is difficult to extract because it is difficult to quantify. Colour can be quantified by spectrocolorimetry which provides very high resolution data quickly and non-destructively. When adapted to sedimentology, spectrocolorimeters prove to be powerful tools due to their low purchase and maintenance costs, and some are portable and easily used in-the-field. Several methods have been used to extract sedimentological data from colorimetric spectra (first derivatives, factorial analysis, etc.). In the present study, we first provide a review of the sedimentological application of spectrophotometers and, after having described these methods, their advantages and disadvantages, we then describe a new tool called the Q7/4 diagram (abscissa L*; Ordinates 700/400 ratio). This new technique permits sedimentological units to be defined, allows the identification of different sediment components and provides 5 distinct poles: Clayey deposits, organic rich deposits (chlorophyll a and by products), altered organic matter deposits, iron rich deposits, carbonated deposits. Coupled with the analysis of first derivative spectra, it is possible to distinguish different pigments linked to the degradation and/or nature of the organic material (Chlorophyll a, melanoidin, etc.), the state of iron oxidation (for example, hematite and goethite-like signatures) and the nature of clays. The Q7/4 diagram permits rapid acquisition of high resolution data on changes of sediment dynamics in geosystems that have been subjected to highly varied climatic/environmental conditions. The instrument is non destructive, easy to use and maintain, portable for use in the field, fast to implement, is capable of high resolution, and has a vast range of possible applications. Spectrocolorimetry appears to provide many advantages and could become an essential and robust tool for preliminary sedimentological studies

Foraging Fidelity as a Recipe for a Long Life: Foraging Strategy and Longevity in Male Southern Elephant Seals

Identifying individual factors affecting life-span has long been of interest for biologists and demographers: how do some individuals manage to dodge the forces of mortality when the vast majority does not? Answering this question is not straightforward, partly because of the arduous task of accurately estimating longevity in wild animals, and of the statistical difficulties in correlating time-varying ecological covariables with a single number (time-to-event). Here we investigated the relationship between foraging strategy and life-span in an elusive and large marine predator: the Southern Elephant Seal (Mirounga leonina). Using teeth recovered from dead males on îles Kerguelen, Southern Ocean, we first aged specimens. Then we used stable isotopic measurements of carbon () in dentin to study the effect of foraging location on individual life-span. Using a joint change-point/survival modelling approach which enabled us to describe the ontogenetic trajectory of foraging, we unveiled how a stable foraging strategy developed early in life positively covaried with longevity in male Southern Elephant Seals. Coupled with an appropriate statistical analysis, stable isotopes have the potential to tackle ecological questions of long standing interest but whose answer has been hampered by logistic constraints

Climatic and cultural changes in the west Congo Basin forests over the past 5000 years

Central Africa includes the world's second largest rainforest block. The ecology of the region remains poorly understood, as does its vegetation and archaeological history. However, over the past 20 years, multidisciplinary scientific programmes have enhanced knowledge of old human presence and palaeoenvironments in the forestry block of Central Africa. This first regional synthesis documents significant cultural changes over the past five millennia and describes how they are linked to climate. It is now well documented that climatic conditions in the African tropics underwent significant changes throughout this period and here we demonstrate that corresponding shifts in human demography have had a strong influence on the forests. The most influential event was the decline of the strong African monsoon in the Late Holocene, resulting in serious disturbance of the forest block around 3500 BP. During the same period, populations from the north settled in the forest zone; they mastered new technologies such as pottery and fabrication of polished stone tools, and seem to have practised agriculture. The opening up of forests from 2500 BP favoured the arrival of metallurgist populations that impacted the forest. During this long period (2500–1400 BP), a remarkable increase of archaeological sites is an indication of a demographic explosion of metallurgist populations. Paradoxically, we have found evidence of pearl millet (Pennisetum glaucum) cultivation in the forest around 2200 BP, implying a more arid context. While Early Iron Age sites (prior to 1400 BP) and recent pre-colonial sites (two to eight centuries BP) are abundant, the period between 1600 and 1000 BP is characterized by a sharp decrease in human settlements, with a population crash between 1300 and 1000 BP over a large part of Central Africa. It is only in the eleventh century that new populations of metallurgists settled into the forest block. In this paper, we analyse the spatial and temporal distribution of 328 archaeological sites that have been reliably radiocarbon dated. The results allow us to piece together changes in the relationships between human populations and the environments in which they lived. On this basis, we discuss interactions between humans, climate and vegetation during the past five millennia and the implications of the absence of people from the landscape over three centuries. We go on to discuss modern vegetation patterns and African forest conservation in the light of these events.Peer reviewe

The role of the southern Indian Ocean in the glacial to interglacial atmospheric CO2 change: organic carbon isotope evidences

International audienc

Pb isotopic compositions of fin whale baleen plates - A clue to unravel individual migrations between the Atlantic Ocean and the Mediterranean Sea?

To assess Mediterranean fin whale ecology and impacts of environmental changes, Pb content and isotopic composition were measured on baleen plates of fin whales stranded on Mediterranean and Bay of Biscay coasts. Pb contents of fin whale baleen plate reflect that of their diet and thus of the dissolved Pb content of the upper 200 meters of the surface ocean. Using Pb isotopes, baleen plates allow reconstituting the evolution of anthropogenic Pb pollution and showing that stranded Mediterranean fin whales constitute a specific population that is resident of the Mediterranean Sea with occasional migrations to the Atlantic Ocean

Long-chain alkenones and U 37 k′ variability along a south―north transect in the Western Pacific Ocean

International audienceIn this paper, we present 50 surface water samples collected during the IMAGES III cruise (June–July 1997) along a transect from New Zealand to the China Sea (42°S–178°E, 21°N–120°E) covering a temperature range from 13.3 to 30.4 °C. A very worthwhile aspect of this study is a coupling of both biomarker (alkenone) and coccolithophorid counting. We show that the U37k′–temperature relationship is very similar to the Prahl et al. [Geochim. Cosmochim. Acta 52 (1988) 2203] culture calibration and to the global core top calibration of Müller et al. [Geochim. Cosmochim. Acta 62 (1998) 1757]. However, in the warmest surface waters of the Western Pacific ocean (>26.4 °C) where Gephyrocapsa oceanica is likely the most widespread species, the associated U37k′ has a constant value of 1.0. The consequence is that above this temperature threshold, U37k′ cannot be used as an accurate paleothermometer

Grazing intensity drives a trophic shift in the diet of common alpine birds

Large mammalian herbivores (LMH) shape vertebrate communities and structure food webs in many terrestrial ecosystems. However, the mechanisms that underlie the effects of LMH on other vertebrates are poorly understood. In France, domestic LMH have grazed alpine and mountain grasslands for thousands of years, profoundly influencing landscapes and wildlife. As LMH modify habitat structure, favour coprophagous insects and compete with herbivorous insects, the diet of insectivorous alpine birds may be deeply influenced by LMH grazing intensity. To investigate this, we sampled common insectivorous birds faeces (water pipit Anthus spinoletta and wheatear Oenanthe oenanthe) in sites characterized by different levels of grazing intensity by domestic and wild herbivores, in the open landscapes of the southern French Alps and the western Pyrenees. We used isotopic discrimination based on nitrogen stable isotope ratios as an indicator of the trophic level of the arthropods found in bird faeces. From isotopic ratios, we found that bird diets shift from mainly herbivorous arthropods at sites of low grazing intensity, to one mainly composed of other groups, such as predatory, detritivorous or coprophagous arthropods, at sites of higher grazing intensity. This result highlights the strong trophic link between LMH and insectivorous birds in open landscapes, contributing to a better understanding of interactions between domestic grazing, an activity that has historically modelled European landscapes, and biodiversity, with particular relevance for landscape management and bird conservation