Environmentally determined spatial patterns of annual plants in early salt-marsh succession versus stochastic distribution in old salt-marsh conditions

It is generally accepted that in terrestrial ecosystems the occurrence and abundance of plant species in late succession stages can be well predicted from prevailing soil conditions whereas in early succession their presence is much more influenced by chance events (e.g. propagule availability). In other words late successional vegetation stages would be deterministically structured, while early succession stages would be of a more stochastic nature.To test this hypothesis, we compared the effect of abiotic environmental factors on vegetation composition and probability of occurrence of single species in two adjacent saltmarshes, differing in age (successional stage). A new salt-marsh of about 14ha was created in 2002 by removing a several meters thick layer of sand and slurry which was deposited on the major part of the salt-marsh along the IJzer estuary in the 1960s. From 2002 onwards, primary colonization started on that sterile substrate by hydrochoric seed dispersal, induced by tidal water currents from an adjacent 4ha old salt-marsh and the latter remained untouched as saltmarsh for more than two hundred years. Between mid August and the end of September 2005, three years after the start of the colonization in the new salt-marsh, vegetation and three abiotic environmental factors (soil texture, salinity and elevation) were described in a set of 155 plots (2m × 2m), distributed over the new and the old salt-marsh.In contrast to the general rule for terrestrial ecosystems, the vegetation composition of the early succession stage of the new salt-marsh appears to be at least as much determined by the combined effect of the measured abiotic factors as that of the old salt-marsh. As revealed by logistic regression the presence/absence of perennial species as well as annual species of the young salt-marsh can be well predicted by the measured abiotic environment. For the old salt-marsh, this also holds for the perennials, but not for the annuals. The stochastic appearance of gaps in the perennial vegetation cover appears to be important for the establishment of annuals in the older salt-marsh

Short-term impact of sheep grazing on salt-marsh vegetation succession in a newly created salt-marsh site

In this paper, the effect of three winter seasons of sheep grazing on cover, composition and species richness of vegetation, Elymus athericus expansion and forage quality of saltmarsh species were studied. Four zones were selected: three in real salt-marsh habitat (low, intermediate and high levels) and the fourth in the transition between salt-marsh and sand dune habitat. In each of the three salt-marsh zones, one site was selected and two sites were designated in the transitional zone. Half of each site was excluded from grazing (so-called exclosures) all year round, while the other half was accessible to sheep from mid-August until mid-June (enclosure areas). At each zone, 10 plots (2m × 2m) were established: five within exclosure and five within enclosure sites. In all plots, the cover of all species was estimated in the growing season in 2005 (initial state) and 2007 (state after two years of grazing). In addition, a total of 1516 quadrates (50cm × 50cm) were used to harvest the biomass of species to estimate the forage quality variation during the grazing period inside the plots. The forage quality variables were the percentages of crude protein, acid detergent fibre and neutral detergent fibre. The data of the cover of dominant salt-marsh species, species richness, total cover, plant composition and forage quality parameters are compared between exclosure and enclosure plots and between two sampling years (2005 and 2007) using repeated measurements (general linear model) separately for each zone. The results showed that after three years of plant succession, sheep grazing had a positive influence on plant richness on the high part of the salt-marsh, a negative effect in the transitional zone and no effect in the other zones. Grazing had no effect on cover and plant composition. Forage quality parameters were affected by sheep grazing only in the low salt-marsh zone. Limonium vulgare had the highest forage quality andElymus athericus had the lowest. It would appear that grazing with the current intensity and number of grazers would fail to hamper the expansion of Elymus athericus. A higher intensity of mixed sheep-cattle or cattle grazing would be needed to better control this highly prolific species

New insights into the use and circulation of reindeer antler in northern Iberia during the Magdalenian (ca. 21-13 cal ka BP)

Interactions between prehistoric foragers and reindeer at the end of the Pleistocene are still poorly documented in northern Iberia, particularly the reasons and means by which their antlers were collected, processed and circulated. Here we review the main osseous industries dated to between 21 and 13 cal ka BP, focusing on the use and circulation of reindeer antler as a raw material for the production of weapons and tools by Magdalenian foragers. Thirty-six reindeer antler artefacts were identified from 11 Iberian sites that are located at either end of the Pyrenees: the Cantabrian region to the west, and to a lesser extent, in Catalonia to the east. Despite biases in the identification of production objectives (end-products), a detailed techno-typological, chronological and geographical analysis of these assemblages reveals both the existence of a consistent reindeer antler industry in northern Iberia and long-distance connections between the Cantabrian region and the Pyrenees. The integration of contemporary macrofaunal data makes it possible to explore the extension of the reindeer?s ecological niche in northern Iberia, as well as strategies for the acquisition and circulation of reindeer antler in the peninsula. Assuming that some reindeer assemblages result from the import of raw materials to supply manufacturing activities, we propose a scenario where the acquisition of reindeer antlers may have been organised at a local scale in the Basque region, and potentially in the neighbouring territories of Navarre, Cantabria and Asturias. On the other hand, in Catalonia, the combination of both faunal and technological data supports the hypothesis that reindeer antlers were imported (along with pelts) over longer distances, probably from the northern Pyrenees.This research was primarily financed by an international collaboration between the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033) and the European Union (NextGenerationEU/PRTR) as part of the HumAntler project (PCI2021-122053-2 B) based at the Grupo I + D + i EvoAdapta (UC). Funding was also provided by the UMR-5608 TRACES laboratory of the University of Toulouse and PID2020-114462 GB-I00 of the Spanish Ministry of Science and Innovation (University of Salamanca)

The global spread of misinformation on spiders

Non peer reviewe

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

The global spread of misinformation on spiders

In the internet era, the digital architecture that keeps us connected and informed may also amplify the spread of misinformation. This problem is gaining global attention, as evidence accumulates that misinformation may interfere with democratic processes and undermine collective responses to environmental and health crises. In an increasingly polluted information ecosystem, understanding the factors underlying the generation and spread of misinformation is becoming a pressing scientific and societal challenge. Here, we studied the global spread of (mis-)information on spiders using a high-resolution global database of online newspaper articles on spider–human interactions, covering stories of spider–human encounters and biting events published from 2010–2020. We found that 47% of articles contained errors and 43% were sensationalist. Moreover, we show that the flow of spider-related news occurs within a highly interconnected global network and provide evidence that sensationalism is a key factor underlying the spread of misinformation. </p

An expert-curated global database of online newspaper articles on spiders and spider bites

Mass media plays an important role in the construction and circulation of risk perception associated with animals. Widely feared groups such as spiders frequently end up in the spotlight of traditional and social media. We compiled an expert-curated global database on the online newspaper coverage of human-spider encounters over the past ten years (2010–2020). This database includes information about the location of each human-spider encounter reported in the news article and a quantitative characterisation of the content—location, presence of photographs of spiders and bites, number and type of errors, consultation of experts, and a subjective assessment of sensationalism. In total, we collected 5348 unique news articles from 81 countries in 40 languages. The database refers to 211 identified and unidentified spider species and 2644 unique human-spider encounters (1121 bites and 147 as deadly bites). To facilitate data reuse, we explain the main caveats that need to be made when analysing this database and discuss research ideas and questions that can be explored with it. </p

Electrochemical S-C bond cleavage in dimolybdenum thiolate/thioether- and bis(thioether)-bridged complexes

International audienceThe electrochemical behavior of complexes possessing bridging thioether ligands, [Mo2Cp2(CO)2(CO) 2(μ-SMe)(μ-SMe2)]+ and [Mo2Cp2(CO)2(μ-SMe2) 2]2+, is reported. Controlled-potential reduction of the dicarbonyl complexes leads to cleavage of the S-C bond(s) of the bridging thioether(s). The different electrochemical and chemical steps producing [Mo2Cp2(CO)2-(μ-SMe)2] are presented. The reactions of the dicarbonyl complexes with cyanide and isocyanide proceed via the substitution of these ligands for CO. In the case of [Mo2Cp2(CO)2(μ-SMe2) 2]2+, the reactions with 1 and 2 equiv. isocyanide produce the singly- and disubstituted derivatives, respectively. The electrochemical reduction of the cyanide analogs [Mo2Cp2(CO)(CN)(μ-SMe)(μ-SMe2)] and [Mo2Cp2(CO)(CN)(μ-SMe2)2] + also results in the cleavage of S-C bond(s). These reactions are faster, and occur at less negative potentials, for the cyanide complexes than for their dicarbonyl precursors, which shows that S-C bond cleavage in these types of complexes is promoted by an increase of the electron density on the Mo2S2 core. © CNRS-Gauthier-Villars