Demographic Histories,Isolation and Social Factors as Determinants of the Genetic Structure of Alpine Linguistic Groups

Great European mountain ranges have acted as barriers to gene flow for resident populations since prehistory and have offered a place for the settlement of small, and sometimes culturally diverse, communities. Therefore, the human groups that have settled in these areas are worth exploring as an important potential source of diversity in the genetic structure of European populations. In this study, we present new high resolution data concerning Y chromosomal variation in three distinct Alpine ethno-linguistic groups, Italian, Ladin and German. Combining unpublished and literature data on Y chromosome and mitochondrial variation, we were able to detect different genetic patterns. In fact, within and among population diversity values observed vary across linguistic groups, with German and Italian speakers at the two extremes, and seem to reflect their different demographic histories. Using simulations we inferred that the joint effect of continued genetic isolation and reduced founding group size may explain the apportionment of genetic diversity observed in all groups. Extending the analysis to other continental populations, we observed that the genetic differentiation of Ladins and German speakers from Europeans is comparable or even greater to that observed for well known outliers like Sardinian and Basques. Finally, we found that in south Tyroleans, the social practice of Geschlossener Hof, a hereditary norm which might have favored male dispersal, coincides with a significant intra-group diversity for mtDNA but not for Y chromosome, a genetic pattern which is opposite to those expected among patrilocal populations. Together with previous evidence regarding the possible effects of “local ethnicity” on the genetic structure of German speakers that have settled in the eastern Italian Alps, this finding suggests that taking socio-cultural factors into account together with geographical variables and linguistic diversity may help unveil some yet to be understood aspects of the genetic structure of European populations.     

Micro-Brillouin scattering measurements in mature and newly formed bone tissue surrounding an implant

The evolution of implant stability in bone tissue remains difficult to assess because remodeling phenomena at the bone-implant interface are still poorly understood. The characterization of the biomechanical properties of newly formed bone tissue in the vicinity of implants at the microscopic scale is of importance in order to better understand the osseointegration process. The objective of this study is to investigate the potentiality of micro-Brillouin scattering techniques to differentiate mature and newly formed bone elastic properties following a multimodality approach using histological analysis. Coin-shaped Ti-6Al-4V implants were placed in vivo at a distance of 200?μm from rabbit tibia leveled cortical bone surface, leading to an initially empty cavity of 200?μm×4.4?mm. After 7 weeks of implantation, the bone samples were removed, fixed, dehydrated, embedded in methyl methacrylate, and sliced into 190?μm thick sections. Ultrasonic velocity measurements were performed using a micro-Brillouin scattering device within regions of interest (ROIs) of 10?μm diameter. The ROIs were located in newly formed bone tissue (within the 200?μm gap) and in mature bone tissue (in the cortical layer of the bone sample). The same section was then stained for histological analysis of the mineral content of the bone sample. The mean values of the ultrasonic velocities were equal to 4.97×10(-3)?m/s in newly formed bone tissue and 5.31×10(-3)?m/s in mature bone. Analysis of variance (p=2.42×10(-4)) tests revealed significant differences between the two groups of measurements. The standard deviation of the velocities was significantly higher in newly formed bone than in mature bone. Histological observations allow to confirm the accurate locations of the velocity measurements and showed a lower degree of mineralization in newly formed bone than in the mature cortical bone. The higher ultrasonic velocity measured in newly formed bone tissue compared with mature bone might be explained by the higher mineral content in mature bone, which was confirmed by histology. The heterogeneity of biomechanical properties of newly formed bone at the micrometer scale may explain the higher standard deviation of velocity measurements in newly formed bone compared with mature bone. The results demonstrate the feasibility of micro-Brillouin scattering technique to investigate the elastic properties of newly formed bone tissue.     

Signals of Climate Change in Butterfly Communities in a Mediterranean Protected Area

The European protected-area network will cease to be efficient for biodiversity conservation, particularly in the Mediterranean region, if species are driven out of protected areas by climate warming. Yet, no empirical evidence of how climate change influences ecological communities in Mediterranean nature reserves really exists. Here, we examine long-term (1998–2011/2012) and short-term (2011–2012) changes in the butterfly fauna of Dadia National Park (Greece) by revisiting 21 and 18 transects in 2011 and 2012 respectively, that were initially surveyed in 1998. We evaluate the temperature trend for the study area for a 22-year-period (1990–2012) in which all three butterfly surveys are included. We also assess changes in community composition and species richness in butterfly communities using information on (a) species’ elevational distributions in Greece and (b) Community Temperature Index (calculated from the average temperature of species'' geographical ranges in Europe, weighted by species'' abundance per transect and year). Despite the protected status of Dadia NP and the subsequent stability of land use regimes, we found a marked change in butterfly community composition over a 13 year period, concomitant with an increase of annual average temperature of 0.95°C. Our analysis gave no evidence of significant year-to-year (2011–2012) variability in butterfly community composition, suggesting that the community composition change we recorded is likely the consequence of long-term environmental change, such as climate warming. We observe an increased abundance of low-elevation species whereas species mainly occurring at higher elevations in the region declined. The Community Temperature Index was found to increase in all habitats except agricultural areas. If equivalent changes occur in other protected areas and taxonomic groups across Mediterranean Europe, new conservation options and approaches for increasing species’ resilience may have to be devised.     

Butterfly and grasshopper diversity patterns in humid Mediterranean grasslands: the roles of disturbance and environmental factors

The present paper studies butterfly, grasshopper and vascular plant communities in ten seasonally flooded grasslands with different anthropogenic disturbance regimes (NW Greece). Disturbance intensity was assessed on the basis of disturbance frequency and type (grazing, mowing, trampling, constructions). The distribution patterns of butterflies are regulated by humidity and elevation (Redundancy Analysis). Elevation, flower-heads abundance, low disturbance intensity and plant species richness predict grasshopper species richness well, while the latter together with humidity predict plant species richness (Generalized Linear Models). Chorthippus lacustris, a critically endangered endemic grasshopper species, is positively associated with humid microhabitats with high flower-heads abundance. An indicator value procedure reveals four butterfly species as being typical species for habitats with a pronounced character of hedgerows and tree lines. Conservation management of grassland butterflies should focus on the maintenance of the humid character of the humid grasslands as well as on the maintenance of hedgerows and tree lines. The reduction of human-induced disturbance towards occasional grazing and mowing seems to benefit both butterfly and grasshopper communities. Finally, we suggest the use of grasshoppers as surrogates for vascular plants and vice versa, given their congruent species richness patterns.     

Towards the co‐ordination of terrestrial ecosystem protocols across European research infrastructures

The study of ecosystem processes over multiple scales of space and time is often best achieved using comparable data from multiple sites. Yet, long‐term ecological observatories have often developed their own data collection protocols. Here, we address this problem by proposing a set of ecological protocols suitable for widespread adoption by the ecological community. Scientists from the European ecological research community prioritized terrestrial ecosystem parameters that could benefit from a more consistent approach to data collection within the resources available at most long‐term ecological observatories. Parameters for which standard methods are in widespread use, or for which methods are evolving rapidly, were not selected. Protocols were developed by domain experts, building on existing methods where possible, and refined through a process of field testing and training. They address above‐ground plant biomass; decomposition; land use and management; leaf area index; soil mesofaunal diversity; soil C and N stocks, and greenhouse gas emissions from soils. These complement existing methods to provide a complete assessment of ecological integrity. These protocols offer integrated approaches to ecological data collection that are low cost and are starting to be used across the European Long Term Ecological Research community.     

How are arthopod communities structured and why are they so diverse? Answers from Mediterranean mountains using hierarchical additive partitioning

Mountains are complex ecosystems supporting a great variety of taxa. Here, we explored the diversity patterns of arthropods in two mountains, pinpointing the spatial scale that accounts most for overall diversity variation, using an additive partitioning framework. Butterflies and Orthoptera were sampled in Rodopi (2012) and Grammos (2013) mountains. Diversity was partitioned into five hierarchical levels (mountain, elevational zone, habitat, transect and plot). We compared the estimated diversity values for each level to the respective permuted values expected by chance, for all species, as well as for species identified as “rare” or “common”. At broader spatial levels, the variation in total diversity was attributed to the beta diversity component: mountains accounted for 20.94 and 26.25% of butterfly and Orthoptera diversity, and elevational zones accounted for 28.94 and 35.87% respectively. At finer spatial scales, beta diversity was higher than expected by chance in terms of the Shannon index. The type of habitat was found to play a significant role only for rare orthopterans. Finally, common species were recognized for shaping overall species diversity. We highlight the importance of the spatial levels of elevation zone and then mountain position in conservation planning, due to the greater beta diversity recorded at this scale as compared to habitat or more finite scales. Monitoring programs might need to adapt different strategies with respect to the focal organisms, and consider patterns of common rather than rare species that found to drive the patterns of the entire community.     

The interaction between bird predation and plant cover in determining habitat occupancy of darkling beetles

Tenebrionid beetles in the Negev Desert exhibit size-related habitat segregation, with larger species found in denser cover. Size-dependent predation by birds has been suggested as the mechanism behind this habitat segregation. Two predictions of this hypothesis were tested: (1) plant cover reduces the predation efficiency of birds upon large tenebrionids, and (2) birds prefer larger species. Both predictions were supported: plant cover reduced predation rate by the most common spring and summer predatory birds: white storks ( Ciconia ciconia ) and stone curlews ( Burhinus oedicnemus ), in cage experiments. Results from preference experiments suggest that tenebrionid species can be divided according to their profitability as prey. Large species are the most profitable, medium-sized species are less profitable but still acceptable and small species are unprofitable and therefore ignored. Field observations demonstrated that the well-vegetated wadi habitats are dominated by large and small species whereas acceptable , medium-sized species are under-represented in this habitat. The results of the cage experiments indicate possible apparent competition between the large profitable and the medium acceptable tenebrionid species in the wadis. Aggregative response of predators in the profitable habitat is suggested as the mechanism leading to truncated distribution of prey species. Large profitable species are refuge-dependent, medium-sized acceptable species use enemy free space and small species are predator independent.     

Woodland strawberry axillary bud fate is dictated by a crosstalk of environmental and endogenous factors

Plant architecture is defined by fates and positions of meristematic tissues and has direct consequences on yield potential and environmental adaptation of the plant. In strawberries (Fragaria vesca L. and F. × ananassa Duch.), shoot apical meristems can remain vegetative or differentiate into a terminal inflorescence meristem. Strawberry axillary buds (AXBs) are located in leaf axils and can either remain dormant or follow one of the two possible developmental fates. AXBs can either develop into stolons needed for clonal reproduction or into branch crowns (BCs) that can bear their own terminal inflorescences under favorable conditions. Although AXB fate has direct consequences on yield potential and vegetative propagation of strawberries, the regulation of AXB fate has so far remained obscure. We subjected a number of woodland strawberry (F. vesca L.) natural accessions and transgenic genotypes to different environmental conditions and growth regulator treatments to demonstrate that strawberry AXB fate is regulated either by environmental or endogenous factors, depending on the AXB position on the plant. We confirm that the F. vesca GIBBERELLIN20-oxidase4 (FvGA20ox4) gene is indispensable for stolon development and under tight environmental regulation. Moreover, our data show that apical dominance inhibits the outgrowth of the youngest AXB as BCs, although the effect of apical dominance can be overrun by the activity of FvGA20ox4. Finally, we demonstrate that the FvGA20ox4 is photoperiodically regulated via FvSOC1 (F. vesca SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1) at 18°C, but at higher temperature of 22°C an unidentified FvSOC1-independent pathway promotes stolon development.

Environmental conditions and apical dominance dictate woodland strawberry plant architecture by regulating axillary bud fate.