Distribution map of Ambrosia artemisiifolia L. (Asteraceae) in Italy

The spread of the invasive and allergenic Ambrosia artemisiifolia L. in Italy was analysed and mapped using distribution data from a wide range of sources. Ambrosia artemisiifolia occupies 1057 floristic quadrants which are mostly distributed in the Po plain. The distribution obtained represents the basis to implement urgent management strategies

Vegetation changes during a 30 years period in several plant communities above the forest line (Emilian Apennines)

The study highlights the changes occurred in 10 homogeneous stands both of Vaccinium and Nardus communities of the Emilian Apennines after 30 years from the first surveys. The stands were sampled by phytosociological and phenological methods in the years 1981-1984 (Puppi, Zanotti & Speranza, 1994 - Phenological studies on Vaccinium and Nardus communities. Fitosociologia) near the mount \u201cCorno alle Scale\u201d (BO). In that time, the locations of the stands were exactly recorded (CRT map 1:10000) and documented by series of photos. In 2011 and 2012 the original sites were found again and the same types of surveys were repeated, with the aim to detect any change and to investigate its possible causes. Main results are here summarized. Community\u2019s structure has become more complex: in particular, Juniperus nana cover is significantly increased; moreover, among Vaccinium species, V.gaultheriodes is going to prevail on V. myrtillus, probably damaged by the shortening of the snow cover duration. In general, species richness is lower than 30 years ago. Many herbaceous species are rarefied or disappeared: in particular Caricetea curvulae and Nardo Callunetea species become reduced in abundance and number. On the other side, only few new species appeared ( e.g. Veratrum album, Maianthemum bifolium, etc.). Changes in vegetation features seem to be due in part to natural dynamics (lighter grazing) and in part to climatic stress. In fact, the climate of the area has become warmer and drier (less snow and less rainfalls in winter, spring and summer) over the last 2 decades, as deduced from data of Marletto et al., 2010 (Atlante idroclimatico dell\u2019Emilia-Romagna 1961-2008. ARPA). Aridity periods (P/T<2), recently occurred in several summers, may be the main causal factor of the population declines in sensitive species; in fact, drought can affect the primary productivity, the reproductive success (most declining species are summer-flowering) and the survival rate

Vegetation changes during a 30 year period in several stands above the forest line (Emilian-Apennines)

The study highlights the changes occurred in several stands of Hyperico richeri-Vaccinietum communities of the high Emilian Apennines after 30 years after the first phytosociological and phenological surveys. In 2012 the same types of surveys were repeated in the original stands, with the aim to detect any change in vegetation structure as well as in species composition and behaviour. The study has pointed out significant changes in all the vegetation stands over the last 30 years. The following trends are displayed in the stands analysed: A) a general decrease of species richness per stand; B) a slight increase of the shrubs/herbs cover ratio, with a significant spreading of Juniperus communis and of Vaccinium uliginosum, sometimes coupled with a reduction of V. myrtillus cover; C) a reduction of Orophytes and of many species belonging to the classes Caricetea curvulae and Nardo Callunetea; D) a xero-thermic trend of plant communities composition (index species analysis). It is noteworthy that many of the declining species flower in the dryest and hottest period of the year (July-August). The results seems to indicate that the changes in vegetation features are due only partly to human causes (lighter grazing) and more widely to climatic stress

Distribution map of <b><i>Ambrosia artemisiifolia</i></b> L. (Asteraceae) in Italy

<p>The spread of the invasive and allergenic <i>Ambrosia artemisiifolia</i> L. in Italy was analysed and mapped using distribution data from a wide range of sources. <i>Ambrosia artemisiifolia</i> occupies 1057 floristic quadrants which are mostly distributed in the Po plain. The distribution obtained represents the basis to implement urgent management strategies.</p