Sandro Pignatti

Bio: Sandro Pignatti is an academic researcher. The author has contributed to research in topics: Genus & Flora. The author has an hindex of 2, co-authored 2 publications receiving 1924 citations.

Plant Life of the Dolomites

Abstract: A few years ago, I was lucky enough to visit the Dolomites as part of a study of facilitation by alpine cushion plants. I remember beautiful scenery, wonderful plant life, and a particularly tasty limoncello sorbet while watching Italy get knocked out of the 2010 World Cup (limoncello 1, Italian World Cup dreams 0). So I was delighted to get the chance to review this book and learn more about this wonderful alpine region. This is a weighty new publication from Springer, and I approached it with some trepidation. However, I should not have worried. One thing the authors never miss is an opportunity to give some good advice. The introduction begins with a section titled ‘‘How to Approach This Book,’’ and the authors state that ‘‘The topic of this book is the plant cover of the Dolomites, and its goal is to make the reader capable of understanding how it is composed, how it was formed, and what its future evolution may be’’ (p ix). It is clear from the outset that this book aims to be more than simply a phytosociological description of the vegetation of the Dolomites. The introduction contains an interesting history of vegetation recording and analysis, including a description of the authors’ own work in the Dolomites and ‘‘Three Itineraries for Getting to Know the Flora of the Dolomites.’’ There is also a description of the data provided in the later chapters, many of which focus on details of the vegetation associations. Chapter 1 then provides a general outline of the environment of the Dolomites. After this introductory overview come the detailed descriptions of the vegetation associations, organized into broad habitat types ranging from the valley bottoms (‘‘Stable Meadows and Vegetation of Fields and Human Settlements’’) to the high mountain tops (‘‘Rupestrian Habitats’’). These habitat groupings are themselves brigaded into sections, from ‘‘The Human Habitat’’ to ‘‘Alpine Vegetation on Dolomite and Limestone.’’ Each habitat chapter begins with a general introduction, including highly detailed descriptions with excellent illustrations, of the ecological and environmental conditions associated with that habitat. As well as providing clear descriptions of the processes regulating the development of vegetation in each habitat type, they discuss, where relevant, the cultural significance and human role in the development and management of these habitats. Then come the detailed descriptions of particular associations, including details of their geology, structure, floristic composition, and distribution. Each vegetation description, and indeed each chapter, is illustrated with excellent photographs and distribution maps, and overall the book is a beautiful object (which is nice to see from Springer, whose finished products are consistently expensive but can vary greatly in production quality). The authors’ enthusiasm for their subject—as well as the depth and breadth of their knowledge—is clear throughout. For example, the book contains many boxes that cover in detail a range of topics, from ‘‘What Is Phytosociology’’ in the introduction to ‘‘The Problem of the Baranci’’ in Chapter 5 on the alpine taiga. For those who don’t know what the Baranci is—quite removed from the problems associated with it—there is a brief but helpful glossary at the end of the book. However, and as set out in the introduction, this book is trying to go further than simply providing descriptions of the habitats and plant communities of the Dolomites. Roughly one third of the book is given over to two sections focusing on the analysis of vegetation data: ‘‘Synthesis, Data Interpretation and Statistical Calculations’’ and ‘‘Conclusions.’’ The synthesis chapters assess the roles played by different types of factors in structuring the vegetation, including physical, chemical, and biotic drivers. The conclusions chapters try to pull this information together to summarize the key processes regulating different aspects of biodiversity in the vegetation of the Dolomites and then attempt to assess how this detailed understanding might help to conserve these environments. I struggled most in these chapters. Overall, I felt at times as though the book would have benefited from the benevolent attention of an editor, because some of the language can be convoluted and slightly impenetrable. I do not write this lightly: I appreciate the immediate advantage given to those who can call English our first language. However, although the authors’ language in many places is, in an absolute sense, accurate, occasionally it is not easy to follow, and I had to read some sentences several times to unpick the basic meaning. In addition, I was sometimes floundered in the book’s latter sections to understand what the conclusions were. For example, I was particularly interested in what Chapter 20, titled ‘‘A New Paradigm: The Approach to Complexity,’’ had to offer. I like a good paradigm. Apparently, ‘‘As the conclusion to this work, an ambitious attempt is presented to interpret the plant life of the Dolomites as a complex system: a synthesizing outline of the vegetation defined by means of ecological information, a new concept of biodiversity, the structuring of the territory, all of which provide the cognitive elements for a new strategy for nature conservation’’ (p 693). This was no small ambition. The analytical approach ‘‘also makes it possible to confront the problems of the sustainable management of resources in a new way’’ (ibid). However, having read MountainMedia Mountain Research and Development (MRD) An international, peer-reviewed open access journal published by the International Mountain Society (IMS) www.mrd-journal.org

Alien flora of Europe: species diversity, temporal trends, geographical patterns and research needs.

Abstract: The paper provides the first estimate of the composition and structure of alien plants occurring in the wild in the European continent, based on the results of the DAISIE project (2004–2008), funded by the 6th Framework Programme of the European Union and aimed at “creating an inventory of invasive species that threaten European terrestrial, freshwater and marine environments”. The plant section of the DAISIE database is based on national checklists from 48 European countries/regions and Israel; for many of them the data were compiled during the project and for some countries DAISIE collected the first comprehensive checklists of alien species, based on primary data (e.g., Cyprus, Greece, F. Y. R. O. Macedonia, Slovenia, Ukraine). In total, the database contains records of 5789 alien plant species in Europe (including those native to a part of Europe but alien to another part), of which 2843 are alien to Europe (of extra-European origin). The research focus was on naturalized species; there are in total 3749 naturalized aliens in Europe, of which 1780 are alien to Europe. This represents a marked increase compared to 1568 alien species reported by a previous analysis of data in Flora Europaea (1964–1980). Casual aliens were marginally considered and are represented by 1507 species with European origins and 872 species whose native range falls outside Europe. The highest diversity of alien species is concentrated in industrialized countries with a tradition of good botanical recording or intensive recent research. The highest number of all alien species, regardless of status, is reported from Belgium (1969), the United Kingdom (1779) and Czech Republic (1378). The United Kingdom (857), Germany (450), Belgium (447) and Italy (440) are countries with the most naturalized neophytes. The number of naturalized neophytes in European countries is determined mainly by the interaction of temperature and precipitation; it increases with increasing precipitation but only in climatically warm and moderately warm regions. Of the nowadays naturalized neophytes alien to Europe, 50% arrived after 1899, 25% after 1962 and 10% after 1989. At present, approximately 6.2 new species, that are capable of naturalization, are arriving each year. Most alien species have relatively restricted European distributions; half of all naturalized species occur in four or fewer countries/regions, whereas 70% of non-naturalized species occur in only one region. Alien species are drawn from 213 families, dominated by large global plant families which have a weedy tendency and have undergone major radiations in temperate regions (Asteraceae, Poaceae, Rosaceae, Fabaceae, Brassicaceae). There are 1567 genera, which have alien members in European countries, the commonest being globally-diverse genera comprising mainly urban and agricultural weeds (e.g., Amaranthus, Chenopodium and Solanum) or cultivated for ornamental purposes (Cotoneaster, the genus richest in alien species). Only a few large genera which have successfully invaded (e.g., Oenothera, Oxalis, Panicum, Helianthus) are predominantly of non-European origin. Conyza canadensis, Helianthus tuberosus and Robinia pseudoacacia are most widely distributed alien species. Of all naturalized aliens present in Europe, 64.1% occur in industrial habitats and 58.5% on arable land and in parks and gardens. Grasslands and woodlands are also highly invaded, with 37.4 and 31.5%, respectively, of all naturalized aliens in Europe present in these habitats. Mires, bogs and fens are least invaded; only approximately 10% of aliens in Europe occur there. Intentional introductions to Europe (62.8% of the total number of naturalized aliens) prevail over unintentional (37.2%). Ornamental and horticultural introductions escaped from cultivation account for the highest number of species, 52.2% of the total. Among unintentional introductions, contaminants of seed, mineral materials and other commodities are responsible for 1091 alien species introductions to Europe (76.6% of all species introduced unintentionally) and 363 species are assumed to have arrived as stowaways (directly associated with human transport but arriving independently of commodity). Most aliens in Europe have a native range in the same continent (28.6% of all donor region records are from another part of Europe where the plant is native); in terms of species numbers the contribution of Europe as a region of origin is 53.2%. Considering aliens to Europe separately, 45.8% of species have their native distribution in North and South America, 45.9% in Asia, 20.7% in Africa and 5.3% in Australasia. Based on species composition, European alien flora can be classified into five major groups: (1) north-western, comprising Scandinavia and the UK; (2) west-central, extending from Belgium and the Netherlands to Germany and Switzerland; (3) Baltic, including only the former Soviet Baltic states; (4) east-central, comprizing the remainder of central and eastern Europe; (5) southern, covering the entire Mediterranean region. The clustering patterns cut across some European bioclimatic zones; cultural factors such as regional trade links and traditional local preferences for crop, forestry and ornamental species are also important by influencing the introduced species pool. Finally, the paper evaluates a state of the art in the field of plant invasions in Europe, points to research gaps and outlines avenues of further research towards documenting alien plant invasions in Europe. The data are of varying quality and need to be further assessed with respect to the invasion status and residence time of the species included. This concerns especially the naturalized/casual status; so far, this information is available comprehensively for only 19 countries/regions of the 49 considered. Collating an integrated database on the alien flora of Europe can form a principal contribution to developing a European-wide management strategy of alien species.

Limitation of stomatal conductance by hydraulic traits: sensing or preventing xylem cavitation?

Abstract: We tested the hypothesis that hydraulic conductance per unit leaf surface area of plant shoots (KSL) determines the maximum diurnal stomatal conductance (gL) that can be reached by plants growing in the field. A second hypothesis was tested that some xylem cavitation cannot be avoided by transpiring plants and might act as a signal for regulating gL. Eleven woody species were studied, differing from each other with respect to taxonomy, wood anatomy and leaf habit. Maximum diurnal gL, transpiration rate (EL), pre-dawn and minimum diurnal leaf water potential (Ψpd and Ψmin, respectively) were measured in the field. The critical Ψ level at which stem cavitation was triggered (Ψcav) was measured on detached branches, using the acoustic method. A high-pressure flow meter was used to measure maximum KSL of 1-year-old shoots. Both gL and EL were positively related to KSL. The whole-plant hydraulic conductance per unit leaf area (KWL) of all the species studied, calculated as the ratio of EL to ΔΨ (=Ψpd-Ψmin) was closely related to KSL. In every case, Ψmin (ranging between –0.85 and –1.35 MPa in the different species) dropped to the Ψcav range or was <Ψcav (ranging between –0.71 and –1.23 MPa), thus suggesting that some cavitation-induced embolism could not be avoided. The possibility is discussed that some cavitation-induced reduction in KSL is the signal for stomatal closure preventing runaway embolism. The lack of correlation of gL to Ψcav is discussed in terms of the inconsistency of Ψcav as an indicator of the vulnerability of plants to cavitation. No differences in hydraulic traits were observed between evergreen and deciduous species.