Editorial: Terrestrial Ecosystem Nitrogen Fluxes via the Atmosphere-Land System

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Environment-human relationships in historical times: The balance between urban development and natural forces at Leptis Magna (Libya)

The relationships between human modification of the environment and natural events in the Roman city of Lepti Magna (UNESCO world heritage), western Libya, are analyzed. For the first time, the history of Leptis Magna is tested against a geomorphological and stratigraphical reconstruction and radiocarbon dating. Historical and archaeological interpretations or analyses indicate the occurrence of different extreme natural events as the cause of the town’s decline: earthquakes, flooding and tsunami. Geological and geomorphological surveys investigated the dynamics of the nearby Wadi Lebda, a major dryland stream that forms the depositional and erosional systems of the settlement area. Alluvial phases were studied by applying traditional stratigraphic analyses of outcrops and hand-cores. Additionally, the mapped flights of inset terrace surfaces provided insights into the human modifications of the natural depositional/erosional environment during historical times and the following alluvial phases affecting the Leptis Magna harbor. The results integrate the archaeological knowledge by providing some independent chronological constraints, and indicate that Leptis Magna history was tightly linked to the Wadi Lebda. Aware of the hazards related to devastating flooding, the Romans were able to cope with the threat posed by the wadi by performing engineering defensive hydraulic works around the town (dam and artificial channels). Once the economic decay began and the society could no longer guarantee the ongoing maintenance of these structures, the decline of the settlement started and the occurrence of destructive floods reclaimed the populated areas. Conversely, the occurrence of a large earthquake (365 CE), or of a tsunami that caused the disruption of the hydraulic systems and the infill of the harbor, has been discarded as primary cause of the decline of Leptis Magna

Environment-man relationships in historical times: the balance between urban development and natural forces at Leptis Magna (Libya).

We analyze the relationships between human modification of the environment and natural events in the Roman city of Leptis Magna (UNESCO world heritage), western Libya. For the first time the history of Leptis Magna is tested against a high resolution geo-morphological and stratigraphical reconstruction and absolute radiocarbon dating. Historical and archaeological sources indicate the occurrence of different natural events as the cause of the town decline: earthquakes, flooding, and tsunamis. Our data indicate that Leptis Magna was tightly linked to the nearby wadi. In fact, aware of the hazards related to violent flooding, the Romans were able to cope with the threat posed by the wadi by engineering defensive hydraulic works around the town. Once economic decay began and the society could no longer guarantee the ongoing maintenance of these structures, the decline of the settlement began and the occurrence of violent floods reclaimed the populated areas. The occurrence of large earthquakes, and the tsunami event that damaged the harbor have been discarded as playing a primary role in the decline of Leptis Magna

Antiproliferative activity of lichen extracts on murine myeloma cells

In the present study we report some preliminary results concerning the evaluation of antiproliferative activity on murine myeloma cells (P3X63-Ag8.653) of crude extracts of two common lichen species, Evernia prunastri and Xanthoria parietina. The results were evaluated by means of the MTT [3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] test, which is commonly used to assess the activity of living cells through mitochondrial dehydrogenases. They indicated that extracts of E. prunastri had no effect, while those of X. parietina significantly affected murine myeloma cell proliferation, with a reduction down to 75% for methanolic extracts. This opens perspectives for deeper investigations extended also to other mammalian cell lines

δ15N of lichens reflects the isotopic signature of ammonia source

Although it is generally accepted that δ15N in lichen reflects predominating N isotope sources in the environment, confirmation of the direct correlation between lichen δ15N and atmospheric δ15N is still missing, especially under field conditions with most confounding factors controlled. To fill this gap and investigate the response of lichens with different tolerance to atmospheric N deposition, thalli of the sensitive Evernia prunastri and the tolerant Xanthoria parietina were exposed for ten weeks to different forms and doses of N in a field manipulation experiment where confounding factors were minimized. During this period, several parameters, namely total N, δ15N and chlorophyll a fluorescence, were measured. Under the experimental conditions, δ15N in lichens quantitatively responded to the δ15N of released gaseous ammonia (NH3). Although a high correlation between the isotopic signatures in lichen tissue and supplied N was found both in tolerant and sensitive species, chlorophyll a fluorescence indicated that the sensitive species very soon lost its photosynthetic functionality with increasing N availability. The most damaging response to the different N chemical forms was observed with dry deposition of NH3, although wet deposition of ammonium ions had a significant observable physiological impact. Conversely, there was no significant effect of nitrate ions on chlorophyll a fluorescence, implying differential sensitivity to dry deposition versus wet deposition and to ammonium versus nitrate in wet deposition. Evernia prunastri was most sensitive to NH3, then NH4+, with lowest sensitivity to NO3−. Moreover, these results confirm that lichen δ15N can be used to indicate the δ15N of atmospheric ammonia, providing a suitable tool for the interpretation of the spatial distribution of NH3 sources in relation to their δ15N signal

Inequality in Human Development: An Empirical Assessment of 32 Countries

One of the most frequent critiques of the HDI is that is does not take into account inequality within countries in its three dimensions. In this paper, we apply a simply approach to compute the three components and the overall HDI for quintiles of the income distribution. This allows a comparison of the level in human development of the poor with the level of the non-poor within countries, but also across countries. This is an application of the method presented in Grimm et al. (World Development 36(12):2527–2546, 2008) to a sample of 21 low and middle income countries and 11 industrialized countries. In particular the inclusion of the industrialized countries, which were not included in the previous work, implies to deal with a number of additional challenges, which we outline in this paper. Our results show that inequality in human development within countries is high, both in developed and industrialized countries. In fact, the HDI of the lowest quintiles in industrialized countries is often below the HDI of the richest quintile in many middle income countries. We also find, however, a strong overall negative correlation between the level of human development and inequality in human development

Where are we now with European forest multi-taxon biodiversity and where can we head to?

The European biodiversity and forest strategies rely on forest sustainable management (SFM) to conserve forest biodiversity. However, current sustainability assessments hardly account for direct biodiversity indicators. We focused on forest multi-taxon biodiversity to: i) gather and map the existing information; ii) identify knowledge and research gaps; iii) discuss its research potential. We established a research network to fit data on species, standing trees, lying deadwood and sampling unit description from 34 local datasets across 3591 sampling units. A total of 8724 species were represented, with the share of common and rare species varying across taxonomic classes: some included many species with several rare ones (e.g., Insecta); others (e.g., Bryopsida) were represented by few common species. Tree-related structural attributes were sampled in a subset of sampling units (2889; 2356; 2309 and 1388 respectively for diameter, height, deadwood and microhabitats). Overall, multi-taxon studies are biased towards mature forests and may underrepresent the species related to other developmental phases. European forest compositional categories were all represented, but beech forests were over-represented as compared to thermophilous and boreal forests. Most sampling units (94%) were referred to a habitat type of conservation concern. Existing information may support European conservation and SFM strategies in: (i) methodological harmonization and coordinated monitoring; (ii) definition and testing of SFM indicators and thresholds; (iii) data-driven assessment of the effects of environmental and management drivers on multi-taxon forest biological and functional diversity, (iv) multi-scale forest monitoring integrating in-situ and remotely sensed information

Epiphytic lichens as indicators of environmental quality in Rome

A synthesis of the studies on lichen diversity carried out in Rome over the period 1982-2003 is presented. In this work, the Lichen Diversity (LD) method has been applied. Besides air pollution, the most important variable affecting the epiphytic lichen flora of Rome, currently updated to 102 taxa, is the influence of the Tyrrhenian Sea. Significant changes in the lichen flora have been noted over the past 20 years, with the lowest diversity now being found in the urban centre and in the eastern and southern sectors, while the "lichen desert" area has decreased in parallel with decreasing concentrations of CO, NOx and SO2

Ecological specialization of lichen congeners with a strong link to Mediterranean-type climate: A case study of the genus Solenopsora in the Apennine Peninsula

An ecological biogeographical perspective provides an understanding of the factors that shape the geographical distribution of organisms, their biodiversity and ecological speciation. Focusing on members of the lichen genus Solenopsora, which are strongly linked to a Mediterranean-type climate, we aimed to depict their environmental niches in the Apennine Peninsula. This area represents their ecological optima, as well as the biogeographical centre of distribution. On the basis of occurrences of Solenopsora congeners, we identified the key ecological factors that shape their environmental niches. Applying an ensemble approach, which merges the results of Random Forest, GLM and MaxEnt algorithms, suitability maps were developed. These are mainly influenced by geological substratum, temperature and precipitation. Occurrence of Solenopsora taxa seems to be mainly governed by low variability in diurnal temperature and tolerance to dryness, with precipitation in the range of 0-20 mm in the driest month and a minimum temperature of >5 \ub0C in the coldest month. The sensitivity to diurnal temperature, an important indicator for climate change, suggests that the taxa confined to Mediterranean bioclimatic types (i.e. Solenopsora grisea, S. marina, S. olivacea subsp. olbiensis and S. olivacea subsp. olivacea) might be good indicators of climatic stability. The geological substratum was a strong limiting factor and separated the taxa into three groups: those growing on calcareous, siliceous and ultramafic substrata. Limited co-occurrence of species confined to one of the three categories suggests that the level of niche differentiation is on a microhabitat level. Accounting for ecological requirements, the taxa differ in their tolerance to sub-optimal conditions. The ecological niches of a sister subspecies pair with different reproduction strategies, fertile S. olivacea subsp. olivacea and sorediate S. olivacea subsp. olbiensis, overlap strongly. However, habitat suitability for S. olivacea subsp. olbiensis is greater in areas with higher precipitation in the driest month, whereas S. olivacea subsp. olivacea is more restricted to warmer and drier areas. We also report new regional records for Italy and the first records of S. cesatii in Serbia and Ukraine, and of S. liparina in Serbia

Chlorophyll degradation and inhibition of polyamine biosynthesis in the lichen Xanthoria parietina under nitrogen stress

This study investigated if some nitrogen (N) compounds commonly used as fertilizers (KNO3, NH4NO3, (NH4)2SO4) cause chlorophyll degradation in the N-tolerant lichen Xanthoria parietina and if polyamines are responsible for the N-tolerance of this species. The results showed that N excess does not cause chlorophyll degradation and suggested the absence of kinetics in the mode of action of the N compounds tested. External supply of inhibitors of polyamine biosynthesis prior to N treatments did not cause any change in the response of chlorophyll integrity, suggesting that at least chlorophyll integrity is not controlled by polyamines