Patterns of modern pollen and plant richness across northern Europe

Sedimentary pollen offers excellent opportunities to reconstruct vegetation changes over past millennia. Number of different pollen taxa or pollen richness is used to characterise past plant richness. To improve the interpretation of sedimentary pollen richness, it is essential to understand the relationship between pollen and plant richness in contemporary landscapes. This study presents a regional-scale comparison of pollen and plant richness from northern Europe and evaluates the importance of environmental variables on pollen and plant richness. We use a pollen dataset of 511 lake-surface pollen samples ranging through temperate, boreal and tundra biomes. To characterise plant diversity, we use a dataset formulated from the two largest plant atlases available in Europe. We compare pollen and plant richness estimates in different groups of taxa (wind-pollinated vs. non-wind-pollinated, trees and shrubs vs. herbs and grasses) and test their relationships with climate and landscape variables. Pollen richness is significantly positively correlated with plant richness (r = 0.53). The pollen plant richness correlation improves (r = 0.63) when high pollen producers are downweighted prior to estimating richness minimising the influence of pollen production on the pollen richness estimate. This suggests that methods accommodating pollen-production differences in richness estimates deserve further attention and should become more widely used in Quaternary pollen diversity studies. The highest correlations are found between pollen and plant richness of trees and shrubs (r = 0.83) and of wind-pollinated taxa (r = 0.75) suggesting that these are the best measures of broad-scale plant richness over several thousands of square kilometres. Mean annual temperature is the strongest predictor of both pollen and plant richness. Landscape openness is positively associated with pollen richness but not with plant richness. Pollen richness values from extremely open and/or cold areas where pollen production is low should be interpreted with caution because low local pollen production increases the proportion of extra-regional pollen. Synthesis. Our results confirm that pollen data can provide insights into past plant richness changes in northern Europe, and with careful consideration of pollen-production differences and spatial scale represented, pollen data make it possible to investigate vegetation diversity trends over long time-scales and under changing climatic and habitat conditions.Peer reviewe

Leaf Trait-Environment Relationships in a Subtropical Broadleaved Forest in South-East China

Although trait analyses have become more important in community ecology, trait-environment correlations have rarely been studied along successional gradients. We asked which environmental variables had the strongest impact on intraspecific and interspecific trait variation in the community and which traits were most responsive to the environment. We established a series of plots in a secondary forest in the Chinese subtropics, stratified by successional stages that were defined by the time elapsed since the last logging activities. On a total of 27 plots all woody plants were recorded and a set of individuals of every species was analysed for leaf traits, resulting in a trait matrix of 26 leaf traits for 122 species. A Fourth Corner Analysis revealed that the mean values of many leaf traits were tightly related to the successional gradient. Most shifts in traits followed the leaf economics spectrum with decreasing specific leaf area and leaf nutrient contents with successional time. Beside succession, few additional environmental variables resulted in significant trait relationships, such as soil moisture and soil C and N content as well as topographical variables. Not all traits were related to the leaf economics spectrum, and thus, to the successional gradient, such as stomata size and density. By comparing different permutation models in the Fourth Corner Analysis, we found that the trait-environment link was based more on the association of species with the environment than of the communities with species traits. The strong species-environment association was brought about by a clear gradient in species composition along the succession series, while communities were not well differentiated in mean trait composition. In contrast, intraspecific trait variation did not show close environmental relationships. The study confirmed the role of environmental trait filtering in subtropical forests, with traits associated with the leaf economics spectrum being the most responsive ones

An estimate of the number of tropical tree species

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher’s alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼40,000 and ∼53,000, i.e. at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼19,000–25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼4,500–6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa

The method of determining the distribution maps of seismic intensity IGSI after recording of a strong seismic event induced by mining

W artykule przedstawiono nową metodę wyznaczania izolinii maksymalnych poziomych amplitud prędkości drgań gruntu PGVHmax po wystąpieniu silnego wstrząsu pochodzenia górniczego. W procedurze obliczeniowej uwzględniane są nie tylko empiryczne relacje tłumienia wyznaczone dla badanego obszaru oraz amplifikacja, ale również rzeczywiste parametry drgań zarejestrowane podczas wstrząsu przez powierzchniowe stacje sejsmometryczne. Opracowana metoda pozwala na bardziej wiarygodne wyznaczanie map rozkładu stopni intensywności potencjalnych skutków drgań od zaistniałego wstrząsu górniczego (intensywności sejsmicznej), według odpowiednich skal opracowanych dla górnictwa węglowego (GSIGZWKW-2012 oraz MSIIS-15) i dla górnictwa rud miedzi w LGOM (GSI-2004/11). Przedstawiono przykład obliczeniowy dla wstrząsu o energii sejsmicznej E=1E8 J, zaistniałego w kopalni węgla w GZW i stwierdzono bardzo dobrą korelację stopni intensywności sejsmicznej IGSI-2012 wyznaczonych nową metodą, z uszkodzeniami udokumentowanymi w zabudowie powierzchniowej w efekcie oddziaływania przedmiotowego wstrząsu. Mapy intensywności drgań od silnych wstrząsów górniczych, wyznaczone według zaproponowanego algorytmu obliczeniowego, mogą być przydatne dla zakładów górniczych, urzędów miast i gmin oraz sądów powszechnych do ustanawiania stref szkodliwego oddziaływania sejsmicznego na zabudowę powierzchniową.The article presents a new method for determining the izolines of the maximum amplitude of vibration velocity, PGVHmax after recording a strong seismic event induced by mining. The calculation procedure does not just include only empirical attenuation low determined for the study area and the amplification effects but also the actual ground motion data recorded during the strong mining seismic event by surface seismic stations. The developed method allows for a more reliable determination of maps of the seismic intensity degrees distribution after mining seismic event, according to the respective scales developed for coal mining (GSIGZWKW-2012 and MSIIS-15) and for copper mining in LGOM (GSI-2004 / 11). An example of calculation for the seismic event of energy E=1E8 J using the new method is presented. A very good correlation between degrees of seismic intensity, IGSI and damage documented in the building after the seismic event was obtained. Maps of seismic intensity of strong mining tremors, designated by the proposed calculation algorithm, can be useful for mining companies, offices of cities and municipal offices and courts for establishing of zones of harmful effects on the building development area

Molecular and quantitative genetics of stone pine (Pinus pinea)

The Mediterranean stone pine is currently on its way to domestication. Its genuine Mediterranean pine nuts are among the most expensive nuts in the world because they are mainly wild-collected from pine forests and woodlands. Despite the wide current distribution of stone pine over the whole Mediterranean biome, old-growth forests are scarce, often associated locally with dynamics on lose sands, coastal dunes or former estuary marshes. The species has been found to be genetically depauperate, putatively due to a population bottleneck in a local refugium during the Last Glacial Maximum confirmed in southern Iberia, and a possibly anthropic range expansion during Holocene. Only recently, cone harvesting and processing mechanisation have allowed for profitable pine nut production from orchard plantations. In Spain and Portugal, first elite clones have been registered for their use as grafted orchard crop