1,721,052 research outputs found
Population status of Anchusa littorea. A Critically Endangered species of Sardinia (Italy)
No full textConservation and restoration of indigenous plants to improve community livelihoods: the Useful Plants Project
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The impact of human trampling on a threatened coastal Mediterranean plant: the case of Anchusa littorea Moris (Boraginaceae)
No full textIn a 5-period study (2007-2011) we examined the effects of human trampling on the last remaining population of Anchusa littorea on the sandy coastal habitat. This species, considered extinct in the wild for several years, was casually rediscovered in a small population at Is Arenas (SW Sardinia). We monthly monitored six trampled and six untrampled permanent plots, mapping individuals and recording their size and reproductive variables. Trampled and untrampled plots showed significant differences with respect to plant density, plant size and reproductive performance (flowers and fruits production). This study demonstrated that human trampling represents a severe threat to the conservation of A. littorea and urgent measures should be planned to protect the unique remnant population in the dune system of Is Arenas. Tourist flow should be redirected and confined to others areas in order to promote the natural expansion of A. littorea in its original habitat. A possible integrated strategy for the conservation and management of the species consists of combining in situ and ex situ measures
The impact of human trampling on Anchusa littorea Moris (Boraginaceae), a coastal threatened Mediterranean plant
No full textPreliminary results on the conservation of Lamyropsis Microcephala (Moris) Dittrich & Greuter (Asteraceae), a threatened endemic species of the Gennargentu massif, Sardinia (Italy)
Full text linkLamyropsis microcephala (Moris) Dittrich & Greuter (Asteraceae) is a perennial species, narrow endemic of Sardinia (Italy) and known only in two sites of the
Gennargentu massif. The aims of this study are to investigate characteristics of the ecology and biology of the species which might be important for its conservation and reassess its conservation status. Here we show the preliminary results of this study, with a focus on the abundance and distribution of the species, its reproductive capacity and the levels of threats. From the data collected in the field it appears that the population had been
fragmented into two subpopulations. The total population covered an area of around 12 hectares and consisted of around 2500 individuals. The reproductive biology of the species, in particular the low production of fertile seeds and absence of seedlings (recruitment) in the field, seems to be one of the main biological causes of the threatened status of the species. Increases in extensive grazing and tourism, linked to the skiing and trekking activities, have been recognized as the major anthropogenic threats to the species. The preliminary results of this study confirm the conservation status of L. m-icrocephala as Critically Endangered
Seasonality effects on plant phenology and seed ecology in Oritrophium peruvianum (Asteraceae), a threatened tropical alpine species
No full textOritrophium peruvianum (Lam.) Cuatr. (Asteraceae) is a threatened perennial herb, endemic to the tropical alpine zone of the Andean páramos and used for medicinal purposes. In this study, its population structure, phenological patterns and seed viability and germination were analysed. In all of the three investigated populations, the proportion of flowering plants was smaller than that of non-flowering. Size structure differed among populations, with two following a normal and one a left-skewed distribution, with a higher percentage of young plants. Flowering was spread throughout the rainy season, with fruiting intensity highest at the end of the rainy season and at the beginning of the dry season. Seedling emergence was limited and appeared to be independent of the season, indicating opportunities for continuous seedling emergence and mortality throughout the year. Seed viability was higher in seeds collected at the end of the dry season compared with those harvested at the end of the rainy season. Laboratory studies suggest that under natural conditions, germination timing is likely to be independent from the season
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Rapid adaptation of seed germination requirements of the threatened Mediterranean species Malcolmia littorea (Brassicaceae) and implications for its reintroduction
No full textMalcolmia littorea (Brassicaceae) is a threatened species growing in the coastal sandy dunes of the west-Mediterranean basin. In this study, the seed germination and seedling emergence requirements of this species were investigated in the only remaining native population in Italy. The highest germination percentage was achieved in darkness with scoring under safe green light at 5-10. °C. Seedling emergence was highest when seeds were buried between 1 and 10. mm in depth. The results suggest that germination and seedling emergence are adapted to Mediterranean coastal habitats by employing a common mechanism of light-inhibited germination and by germinating at cooler temperatures before the onset of the summer drought. Seeds were also collected from plants cultivated at a botanical garden and from plants reintroduced by sowing or by transplanting. For those populations, germination was maximal between 10-25. °C, suggesting that the thermal germination behaviour may be affected by the maternal environment of seed production within one generation. It is suggested to use seeds produced in the same environment to which they will be used for the reintroduction of this species
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