Annual Weedy Species of Erigeron in the Northern Iberian Peninsula: a Review

A revision of the alien Erigeron species formerly included in Conyza found in the northern Iberian Peninsula is presented. A close examination of numerous specimens collected by the authors as well as voucher specimens preserved at several herbaria has helped to clarify several aspects regarding this group. Four species have been recognised in the study area: Erigeron canadensis (=Conyza canadensis), E. bonariensis (=C. bonariensis), E. sumatrensis (=C. sumatrensis) and E. floribundus (=C. floribunda, including C. bilbaoana). They occupy anthropogenic habitats, such as road edges, abandoned fields, crops and waste ground, as well as natural and semi-natural communities, such as nitrophilous river bar communities and ruderal communities on coastal dunes subjected to substantial levels of anthropogenic disturbance. Erigeron sumatrensis and E. floribundus emerge as the two most frequent taxa. Erigeron canadensis, regarded in the past as the most widespread species of the group, is almost absent from the study area, especially from the Atlantic watershed. Furthermore, an important number of specimens previously identified as E. bonariensis do actually correspond to E. sumatrensis. No hybrids have been found. A detailed identification key highlighting the main features that help to separate the four Erigeron species is presented. Finally, as E. floribundus is the most controversial species in the group and the last to arrive, we include a study of its expansion across western Europe, where it has become a frequent alien especially along the Atlantic regions in the last century.This work was supported by the Basque Government (project IT936-16)

Environmental drivers and spatial scaling of species abundance distributions in Palaearctic grassland vegetation

[EN] Species abundance distributions (SADs) link species richness with species abundances and are an important tool in the quantitative analysis of ecological communities. Niche-based and sample-based SAD models predict different spatial scaling properties of SAD parameters. However, empirical research on SAD scaling properties is largely missing. Here we extracted percentage cover values of all occurring vascular plants as proxies of their abundance in 1725 10-m(2) plots from the GrassPlot database, covering 47 regional data sets of 19 different grasslands and other open vegetation types of the Palaearctic biogeographic realm. For each plot, we fitted the Weibull distribution, a model that is able to effectively mimic other distributions like the log-series and lognormal, to the species-log abundance rank order distribution. We calculated the skewness and kurtosis of the empirical distributions and linked these moments, along with the shape and scale parameters of the Weibull distribution, to plot climatic and soil characteristics. The Weibull distribution provided excellent fits to grassland plant communities and identified four basic types of communities characterized by different degrees of dominance. Shape and scale parameter values of local communities on poorer soils were largely in accordance with log-series distributions. Proportions of subdominant species tended to be lower than predicted by the standard lognormal SAD. Successive accumulation of plots of the same vegetation type yielded nonlinear spatial scaling of SAD moments and Weibull parameters. This scaling was largely independent of environmental correlates and geographic plot position. Our findings caution against simple generalizations about the mechanisms that generate SADs. We argue that in grasslands, lognormal-type SADs tend to prevail within a wider range of environmental conditions, including more extreme habitats such as arid environments. In contrast, log-series distributions are mainly restricted to comparatively species-rich communities on humid and fertile soils.We thank all vegetation scientists who carefully collected the plant diversity data and contributed them to GrassPlot. The Eurasian Dry Grassland Group (EDGG) and the International Association for Vegetation Science (IAVS) supported the EDGG field workshops, which generated a core part of the GrassPlot data. The Bavarian Research Alliance (via the BayIntAn scheme) and the Bayreuth Center of Ecology and Environmental Research (BayCEER) funded the initial GrassPlot workshop during which the database was established (grants to Jurgen Dengler). Werner Ulrich acknowledges support from the Polish National Science Centre (Grant 2017/27/B/NZ8/00316). Idoia Biurrun and Juan Antonio Campos were partly supported by the Basque Government (IT936-16). Goffredo Filibeck was partly supported by the MIUR initiative "Department of Excellence" (Law 232/2016) granted to DAFNE. Peter Torok was supported by the NKFIH K 119225 and K 137573 projects and the HAS Momentum Program during the manuscript preparation. Franz Essl appreciates funding by the Austrian Science Foundation FWF (Grant I 3757-B29)

Flora y vegetación de los ríos y humedades de Navarra

Se estudia la vegetación edafohigrófila y edafohalófila de los ríos, humedales y saladares de Navarra. El territorio comprende dos cuencas hidrográficas: la cuenca cantábrica, con el Bidasoa como río principal, y la cuenca mediterránea, cuyo río principal, el Ebro, recibe aquí a algunos de sus afluentes más importantes: Ega, Arga y Aragón. En este amplio territorio existe gran variedad de zonas húmedas, desde las turberas de las montañas septentrionales hasta los barrancos salinos y cubetas endorreicas de las Bardenas. Esta diversidad de medios viene dada por la gran variedad litológica y climática que presenta la Provincia. Se reconocen dos macrobioclimas, templado y mediterráneo, que presentan los termotipos mesotemplado, supratemplado, orotemplado y criorotemplado, y mesomediterráneo superior y supramediterráneo inferior, respectivamente. En cuanto a ombrotipos, reconocemos los siguientes: hiperhúmedo (incluido ultrahiperhúmedo), húmedo, subhúmedo, seco y semiárido. Toda esta diversidad climática y litológica tiene su reflejo en la sectorización biogeográfica del territorio, en el que reconocemos dos regiones: Eurosiberiana y Mediterránea. Dentro de éstas, se presentan en Navarra seis sectores biogeográficos: Cántabro-Euskaldun, Pirenaico occidental, CastellanoCantábrico, Somontano aragonés, Riojano y Bardenas-Monegros. método fitosociológico de la escuela sigmatista de Braun-Blanquet ; se han reconocido 143 tipos distintos de comunidad, que se agrupan en 28 clases fitosociológicas. Se describen como nuevos los siguientes sintaxones: - Salicetum neotrichae Br.-BI. and 0. Bolós 1958 salicetosum lambertianae subass. nova. - Loto pedunculati-Juncetum conglomerati M. Herrera and F. Prieto in T. E. Díaz and F. Prieto 1994 juncetosum acutiflori subass. nova. - Senecioni aquatici-Juncetum acutiflori Br-BI. and Tüxen 1952 molinietosum caeruleae subass. nova..

Flora y vegetación de los ríos y humedades de Navarra

Se estudia la vegetación edafohigrófila y edafohalófila de los ríos, humedales y saladares de Navarra. El territorio comprende dos cuencas hidrográficas: la cuenca cantábrica, con el Bidasoa como río principal, y la cuenca mediterránea, cuyo río principal, el Ebro, recibe aquí a algunos de sus afluentes más importantes: Ega, Arga y Aragón. En este amplio territorio existe gran variedad de zonas húmedas, desde las turberas de las montañas septentrionales hasta los barrancos salinos y cubetas endorreicas de las Bardenas. Esta diversidad de medios viene dada por la gran variedad litológica y climática que presenta la Provincia. Se reconocen dos macrobioclimas, templado y mediterráneo, que presentan los termotipos mesotemplado, supratemplado, orotemplado y criorotemplado, y mesomediterráneo superior y supramediterráneo inferior, respectivamente. En cuanto a ombrotipos, reconocemos los siguientes: hiperhúmedo (incluido ultrahiperhúmedo), húmedo, subhúmedo, seco y semiárido. Toda esta diversidad climática y litológica tiene su reflejo en la sectorización biogeográfica del territorio, en el que reconocemos dos regiones: Eurosiberiana y Mediterránea. Dentro de éstas, se presentan en Navarra seis sectores biogeográficos: Cántabro-Euskaldun, Pirenaico occidental, CastellanoCantábrico, Somontano aragonés, Riojano y Bardenas-Monegros. método fitosociológico de la escuela sigmatista de Braun-Blanquet ; se han reconocido 143 tipos distintos de comunidad, que se agrupan en 28 clases fitosociológicas. Se describen como nuevos los siguientes sintaxones: - Salicetum neotrichae Br.-BI. and 0. Bolós 1958 salicetosum lambertianae subass. nova. - Loto pedunculati-Juncetum conglomerati M. Herrera and F. Prieto in T. E. Díaz and F. Prieto 1994 juncetosum acutiflori subass. nova. - Senecioni aquatici-Juncetum acutiflori Br-BI. and Tüxen 1952 molinietosum caeruleae subass. nova..

Climate and Human Pressure Constraints Co-Explain Regional Plant Invasion at Different Spatial Scales

Alien species invasion represents a global threat to biodiversity and ecosystems. Explaining invasion patterns in terms of environmental constraints will help us to assess invasion risks and plan control strategies. We aim to identify plant invasion patterns in the Basque Country (Spain), and to determine the effects of climate and human pressure on that pattern. We modeled the regional distribution of 89 invasive plant species using two approaches. First, distance-based Moran's eigenvector maps were used to partition variation in the invasive species richness, S, into spatial components at broad and fine scales; redundancy analysis was then used to explain those components on the basis of climate and human pressure descriptors. Second, we used generalized additive mixed modeling to fit species-specific responses to the same descriptors. Climate and human pressure descriptors have different effects on S at different spatial scales. Broad-scale spatially structured temperature and precipitation, and fine-scale spatially structured human population density and percentage of natural and semi-natural areas, explained altogether 38.7% of the total variance. The distribution of 84% of the individually tested species was related to either temperature, precipitation or both, and 68% was related to either population density or natural and semi-natural areas, displaying similar responses. The spatial pattern of the invasive species richness is strongly environmentally forced, mainly by climate factors. Since individual species responses were proved to be both similarly constrained in shape and explained variance by the same environmental factors, we conclude that the pattern of invasive species richness results from individual species' environmental preferences.This study was supported by the projects IT299-10 for research groups and ETORTEK10/34 of Etortek program of the Basque Government, CGL2009-13317-C03-02 of the Spanish Ministry of Science and Innovation and 17/91 of Catedra Unesco of the University of the Basque Country UPV/EHU. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This study was supported by the projects IT299-10 for research groups and ETORTEK10/34 of Etortek program of the Basque Government, CGL2009-13317-C03-02 of the Spanish Ministry of Science and Innovation and 17/91 of Catedra Unesco of the University of the Basque Country UPV/EHU. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We would like to thank Miguel de Caceres (Forest Science Center of Catalonia) and the editor and two anonymous referees for the revision of previous versions of the manuscript and the suggestion of many useful improvements