1,721,207 research outputs found
Analisi della rappresentatività e della gestione della flora minacciata nel sistema di aree protette della Liguria
No full textA Design Rationale Based Environment for Cooperative Maintenance
No full textThis paper describes Cooperative Maintenance Conceptual Model (CM2), a conceptual model aimed at supporting software maintenance in a collaborative fashion. The main goal of CM2 is to support the software maintenance process through the acquisition, structuring and distribution of the information concerned with the maintenance process itself. Information is structured as a network of linked comments and concerns both the analysis and design activities (Rationale in the Large) and the implementation of a change (Rationale in the Small). We also present COMANCHE (COoperative MAintenance Network Centered Hypertextual Enviroment), an enviroment which reflects the CM2 ideas and principles
L’approccio combinato di Species Distribution Models e Adaptive Cluster Sampling per valutare la consistenza di popolazioni licheniche a rischio estinzione. Un esempio per il genere Crespoa.
No full textDivergence is not enough: the use of ecological niche models for the validation of taxon boundaries
No full textDelimiting taxon boundaries is crucial for any evolutionary research and conservation
regulation. In order to avoid mistaken description of species, the approach of integrative
taxonomy recommends considering multidisciplinary lines of evidence, including
ecology. Unfortunately, ecological data are often difficult to quantify objectively. Here
we test and discuss the potential use of ecological niche models for validating taxon
boundaries, using three pairs of closely related plant taxa endemic to the south-western
Alps as a case study. We also discuss the application of ecological niche models
for species delimitation and the implementation of different approaches.
• Niche overlap, niche equivalency and niche similarity were assessed both in multidimensional
environmental space and in geographic space to look for differences in the
niche of three pairs of closely related plant taxa.
• We detected a high degree of niche differentiation between taxa although this result
seems not due to differences in habitat selection. The different statistical tests gave
contrasting outcomes between environmental and geographic spaces.
• According to our results, niche divergence does not seem to support taxon boundaries
at species level, but may have had important consequences for local adaptation and in
generating phenotypic diversity at intraspecific level. Environmental space analysis
should be preferred to geographic space as it provides more clear results. Even if the
different analyses widely disagree in their conclusions about taxon boundaries, our
study suggests that ecological niche models may help taxonomists to reach a decision
The importance of stability throughout time in affecting the geographical pattern of endemism richness
No full textClimate change is one of the greatest threats to plant endemisms, particularly in mountain ecosystems that often show a high rate of endemism. Studies suggest that current centers of endemism are typically located in areas where the rugged mountainous topography buffered the effect of past climate changes and will probably buffer also the future changes.
To evaluate climatic stability we assessed shift in distribution of Köppen climatic types form last interglacial to present. Using species distribution models, we projected the climatic niche of 100 plant species endemic or subendemic to SW Alps (about 60% of all endemic and subebdemic species) in past (i.e., last interglacial, last glacial maximum and middle Holocene) and future (i.e., year 2070 using both an optimistic and a pessimistic scenario) climates.
We detected a higher current endemism richness (both potential and known) in areas climatically stable during the past than in not stable areas. We found a significant positive correlation between richness throughout past climates and both potential and known current endemism richness. Similarly, we found a significant positive correlation between future potential endemism richness and both past stability and current potential endemism richness. Nevertheless, endemic species in the SW Alps will experience high range loss (65.5% and 82.3% in the optimistic and pessimistic scenarios, respectively), not counterbalanced by range gain in adjacent areas because of low dispersal capabilities.
Our results suggest that, despite the ability of microrefugia to remain relatively stable and support high diversity in the future, absolute levels of endemism in the SW Alps will likely decline considerably, due to the inability of endemic species to disperse at a rate consistent with future climate change
Indagini tassonomiche su Iberis (Brassicaceae) in Liguria
No full textTramite un approccio di tassonomia integrata, e in particolare confrontando dati morfologici, di nicchia sia climatica sia pedologica, questo studio si pone l’obiettivo di definire le entità appartenenti al genere Iberis presenti in Liguria
Indagini biosistematiche sulle specie di Centaurea (Asteraceae) endemiche di Calabria. Il quadro distributivo
No full textMoehringia L. - Moehringia
No full textDescrizione delle specie italiane apparteenti al genere Moehringia. Chiave dicotomica per il riconoscimento delle specie
Between past and future: legacy and fate of an important centre of endemism for the Mediterranean region
No full textClimate change is one of the greatest threats to biodiversity, particularly in mountain ecosystems, which
often show high endemism rate. Studies on past climate changes suggested that current centers of endemism
are placed where climatic fluctuations were less pronounced (because of mountainous topography) and that
these areas will be less affected by climate change in the future (1). However, this doesn’t mean that these
areas will not experience drastic climate change effects; in fact, several evidences indicate that mountain
endemics are disproportionally exposed to climate change, because usually they are characterized by small
range size, narrow ecological tolerance and poor dispersal ability (2).
SW Alps are one the most important centers of endemism of the Mediterranean Basin and are particularly
exposed to climate change threat due to the contemporaneous effects of temperature increase and
precipitation decrease, as other Southern European mountain systems (3). Taking into account dispersal
abilities, we used Species Distribution Models to analyze the distribution of suitable climatic conditions for
100 plant species endemic or subendemic of SW Alps (about 60% of endemisms of this area). We projected
predicted suitability in past (i.e.: last interglacial, last glacial maximum, middle Holocene), current and
future (i.e: year 2070) time slices. For each time slice we elaborate a map of potential species richness; for
each species we also calculated the percentage of range loss and gain in the future, considering both
optimistic and pessimistic emission scenarios
Niche divergence between putative taxa: ecological niche models in taxonomic researches
No full textFor over a century, species delimitation was a critical task for biologists, concerning both species concept
and operational methods necessary for the individuation of taxa boundaries. According to the recent
approach of integrative taxonomy, species have to be considered as hypotheses that should be tested with
different methods. Ecological interchangeability can be an element that can corroborate the separation of two
putative taxa, but ecological data are often difficult to use. Ecological Niche Models (ENMs) provide a
quantification of niche parameters and could be a useful tool for investigating taxa boundaries. For this
purpose, we used ENMs for testing ecological (climatic) differentiation in three pairs of related taxa recently
subdued to taxonomical revisions without explicitly considering ecological evidences.
The selected taxa pairs are: Rhaponticum bicknellii (Briq.) Banfi, Galasso & Soldano and R. heleniifolium
Godr. & Gren.; Gentiana burseri subsp. actinocalyx Polidori and Gentiana burseri subsp. villarsii (Griseb.)
Rouy Fritillaria tubaeformis Gren. & Godr. subsp. moggridgei (Baker) Rix and Fritillaria tubaeformis
subsp. tubaeformis. For each pair, we assessed niche overlap, niche equivalency and niche similarity in both
multidimensional environmental space (E-space) and geographical space (G-space)
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