Does Recruitment trigger negative Density-Dependent Feedback loops in Stream-Dwelling Salmonids?

I explored the hypothesis that recruitment may stabilize the numerical dynamics of stream-dwelling salmonids by triggering density-dependent feedback loops through the operation of recruitment-dependence on individual growth, mortality, life span and maximum size and their effects on fecundity. I examined 98 cohorts of two Salmo trutta populations of northern Spain and a population of Jutland (Denmark) located 2400 km apart Recruitment, growth, mortality, life span and maximum size were inter-related, were recruitment-dependent and described negative power trajectories. In the Spanish populations, faster growing individuals of weakly recruited cohorts with lower mortality attain longer life span and larger size. Hence, larger females spawning more abundant, larger eggs that, in turn, induce stronger cohorts of higher spawners’ abundance, recruitment and mortality. The mortality patterns match the self-thinning patterns, an ultimate expression of competition. Significant relationships among self-thinning slopes and mortalities rates with increasing recruitment demonstrate that the rate at which density-driven mortality is higher, the stronger the intensity of intraspecific competition. Space-limited habitat and size-dependent resource availability underpinning site-specific carrying capacities suggest that interference competition is the primary mechanism underpinning population regulation.

Effects of diversifying the planting period of maize on herbivorous and their natural enemies

Knowledge of the specific insect densities during crop development is necessary to perform appropriate measures for the control of insect pests and to minimize yield losses. In a previous study, both spatial and temporal approaches were adopted to analyse the influence of landscape structure and field variables on herbivore and predatory insects on maize. Both types of variables influenced insect abundance, but the highest effect was found with maize phenology. Given that the field planting date could modulate the influence produced by the structure of the landscape on herbivores and predatory insects, analyses of population dynamics must be performed at both the local and landscape levels. The anterior prompted us to study these aspects in the two common planting periods (early and late) in northern Spain. The present study tests the hypothesis that the period of maize planting could have a higher effect than phenology or interannual variation on the abundance of natural enemies and herbivores on maize. Our results showed that only the abundances of other herbivore thrips and Syrphidae were significantly different between the two planting periods. Moreover, we found significant effects of planting period when we performed yearly analysis in 2015 for Coccinellidae and Chrysopidae and in 2016 and 2017 for Aeolothrips sp. Most of the taxa had abundance peaks in earlier growth stages, which are related to pollination (before or during), while only Stethorus punctillum and Syrphidae increased later in the season. Furthermore, Frankliniella occidentalis, aphids, Syrphidae and Coccinellidae registered higher abundances in fields sown in the late planting period than in the rest of the insect species. The results of the present study highlight the effects of sowing dates on insect dynamics in maize.

Is the Strawberry Tree, Arbutus unedo (Ericaceae), native to Ireland, or was it brought by the first copper miners?

The Strawberry Tree (Arbutus unedo L.) is often referred to as one of Ireland’s ‘Lusitanian’ species to describe its disjunct distribution, since it is absent from Britain and is mainly found around the Mediterranean Sea and on the Iberian Peninsula. In Ireland, it is regarded as native in the south-west and in Co. Sligo. However, a recent genetic study suggests that it could have been introduced to Ireland directly from northern Spain. This possibility was previously dismissed, since palynological and archaeological evidence showed it to be present in south-west Ireland 4,000 years ago. Here, we examine how an introduction might have occurred prior to this date, by first reviewing what is known of its distribution, ecology and history in Ireland along with archaeological information. Then, combining an updated distribution of A. unedo where it is regarded as native in Ireland with historical accounts, palynological and archaeological records and other information from the literature, we present two online maps, designed to be an ongoing accessible resource. The information has enabled us to propose a means by which A. unedo might have arrived in Ireland with miners who came to work the first known copper mine in north-west Europe, in the Chalcolithic phase of the Late Neolithic, which was at Ross Island on Lough Leane in Co. Kerry. The species’ distribution today suggests that it then spread with subsequent Bronze Age copper mining activity in south-west Ireland, though this is unlikely to account for its arrival in Co. Sligo. Previous suggestions that A. unedo was once much more widely distributed in Ireland and subsequently contracted due to preferential cutting for smelting, are shown to be unfounded.

To be or not to be: reassessing the origins of portable art in the Cantabrian Region (Northern Spain)

The characterization of the first portable artistic depictions in Cantabrian Spain is crucial for comprehension of the symbolic development of Neandertals and Homo sapiens in the context of the passage from the Middle to the Upper Paleolithic. However, despite the importance of these first graphic representations, their study has tended to lack the application of suitable methodologies to be able to discriminate between graphic activity and other kind of alterations (use-wear, taphonomic, or post-depositional). The present study has examined a significant sample of Middle and Upper Paleolithic lithic and osseous objects from Cantabrian Spain that have been cited as evidence of graphic activity in the literature. The contexts in which the objects were found have been considered, and the objects have been analyzed through the microscopic observation of the marks to distinguish between incisions, pecking, and engraving made for a non-functional purpose (graphic activity) and those generated by diverse functional actions or taphonomic processes (cutmarks, trampling, root marks, percussion scars, and use-wear). The results show that some regional Middle Paleolithic osseous objects display incisions that are neither functional nor taphonomic and whose characteristics are similar to graphic evidence attributed to Neandertals in Europe and the Near East. In turn, the first portable art produced by Homo sapiens in the Cantabrian Spain seems to be limited mostly to linear signs, and no figurative representation can be recognized until the Gravettian. This appears to indicate a particular idiosyncrasy of the region in the Early Upper Paleolithic, which, in comparison with other regions such as south-west France and the Swabian Jura, shows a later and less abundant production of portable art.

A Women Moralising Crusade in the Peninsular War: Bishop Menéndez de Luarca and his Visit to England

The Bishop of Santander, Rafael Tomás Menéndez de Luarca, was an enthusiastic representative of the High Catholic Church in Spain between 1784 and 1819. As a declared enemy of France since the Revolution, the Napoleonic troops’ advance into Northern Spain forced him to flee into Asturias in November 1808. In May 1809 Menéndez de Luarca managed to escape to Britain, a country he considered ‘heretic’. His stay there marked a watershed in the moralising campaign he had started at the beginning of his bishopric. Back in Spain, the progressive loosening of traditional Catholic morals he found in Cádiz had, in his opinion, a negative impact on the Spanish struggle against Napoleon. Menéndez de Luarca’s concern for what he had viewe as women’s outrageous fashion while in England increased in the Andalusian city. This article aims to analyse the impact of the bishop’s English experience on the peculiar campaign he began in Cádiz in 1809 to ‘improve’ women’s conduct. His personal crusade ended up with the publication of a work with an eloquent title, Las descamisadas o envenustadas modernas españolas (1812). A critical revision of this text includes a brief socio-linguistic analysis of the term ‘descamisadas’. This study is completed with an evaluation of the civil authorities’ acceptance of the measures suggested by Menéndez de Luarca, together with their social impact.

Weather Variables Associated with Spore Dispersal of Lecanosticta acicola Causing Pine Needle Blight in Northern Spain

In the last decade, the impact of needle blight fungal pathogens on the health status of forests in northern Spain has marked a turning point in forest production systems based on Pinus radiata species. Dothistroma needle blight caused by Dothistroma septosporum and D. pini, and brown spot needle blight caused by Lecanosticta acicola, coexist in these ecosystems. There is a clear dominance of L. acicola with respect to the other two pathogens and evidence of sexual reproduction in the area. Understanding L. acicola spore dispersal dynamics within climatic determinants is necessary to establish more efficient management strategies to increase the sustainability of forest ecosystems. In this study, spore counts of 15 spore traps placed in Pinus ecosystems were recorded in 2019 and spore abundance dependency on weather data was analysed using generalised additive models. During the collection period, the model that best fit the number of trapped spores included the daily maximum temperature and daily cumulative precipitation, which was associated to higher spore counts. The presence of conidia was detected from January and maximum peaks of spore dispersal were generally observed from September to November.

Variability of diatom community composition and structure in mountain streams

Small rivers support high levels of biodiversity, being especially sensitive to the effects of global change. Temporal records of community composition in minimally impaired streams can be used to explore trends in biodiversity in response to climate change and natural temporal variation. We approached the comparison of two time periods (2003–2008 and 2016–2020) to study whether the composition of diatom assemblages changed over time in twenty-three streams of the mountain range of Picos de Europa (Northern Spain). The stream’s water chemistry indicated significant decreases in N_NO3− and P_PO43− content over time. In these minimally disturbed streams, the specific diatom community was dominated by Achnanthidium pyrenaicum, Achnanthidium minutissimum and Cocconeis euglypta. PERMANOVA analyses did not identify significant changes in diatom assemblage composition between periods or river types. Diatom indices (e.g. IPS, NORTIdiat) indicated high or good ecological status and relatively high alpha diversity values were found in these mountain rivers during the studied years. Although diversity and evenness showed a significant decrease over time, the temporal stability of the river-type diatom reference community between the two periods should be considered as an indicator of biodiversity persistence of high importance when monitoring the ecological status following the reference condition approach.