Search results for "VAS"

Northward invasion of the parasitic deer ked ( Lipoptena cervi), is there geographical variation in pupal size and development duration?

2010

SUMMARYThe deer ked (Lipoptena cervi) is a common ectoparasite of cervids. During the last decades the species has rapidly invaded in northern Europe, especially in Finland, towards the north and increased its prevalence on the moose population. Consequently, during this rapid invasion the deer ked has faced more severe climatic conditions. We studied whether pupal size (measured as pupal weight) and pupal development duration of the deer ked varies along historical invasion zones and temperature zones towards north in Finland. Moreover, we explored possible size- and gender-dependent variation in pupal development duration. We divided wild-collected pupae in respect to their origin in two …

Diet and trophic niche of the invasive signal crayfish in the first invaded Italian stream ecosystem.

2021

The occurrence of the signal crayfsh Pacifastacus leniusculus in the Valla Stream was the frst established population of this invasive species recorded in an Italian stream ecosystem. We evaluated the seasonality of diet and trophic niche of invasive signal crayfsh in order to estimate the ecological role and efects on native communities of the stream ecosystem. We studied the diferences in food source use between sexes, life stages and seasons using carbon and nitrogen stable isotope analyses. To supplement stable isotope analyses, we evaluated food source usage using traditional stomach content analysis. We tested the hypothesis that juveniles have a diferent diet, showing diferent trophi…

First record of Percnon gibbesi (H. Milne Edwards, 1853) (Crustacea: Decapoda: Percnidae) from Egyptian waters

2011

3 pages, 2 figures

The ongoing naturalisation of Eucalyptus spp. in the Mediterranean Basin: new threats to native species and habitats

2019

The genus Eucalyptus has been widely introduced into many regions of the world outside its native range and has become invasive in some Mediterranean biomes (e.g. in southern Africa and California). In the Mediterranean Basin and Europe, eucalypts were introduced at the end of the 18th century. However, natural regeneration events in these regions are recent in time and limited in terms of affected areas, except for the Iberian Peninsula. An updated overview about the natural spread of Eucalyptus species in Italy is still lacking. This paper aims to fill this knowledge gap, using both published data and unpublished field data regarding naturalisation events, with a specific focus on Sicily.…

Seasonal effects on mortality rates and resprouting of stems treated with glyphosate in the invasive tree of heaven (Ailanthus altissima (Mill.) Swin…

2015

Tree of heaven (Ailanthus altissima) is regarded as invasive within urban and natural areas worldwide. Efficient methods to control it are significantly needed if we are to limit its well-known environmental and economic impacts. Up to now the use of herbicides has proven necessary since following mechanical damage, Ailanthus vigorously resprouts. However, the seasonal response of Ailanthus stems, treated with herbicides, has never been assessed. We compared the control efficacy recorded in autumn, winter and summer in an abandoned suburban citrus grove in Sicily, under Mediterranean-climate conditions. Glyphosate was injected within drill holes made in knee-high cut trees. Tree mortality a…

Assessing global range expansion in a cryptic species complex: insights from the red seaweed genus Asparagopsis (Florideophyceae)

2017

The mitochondrial genetic diversity, distribution and invasive potential of multiple cryptic operational taxonomic units (OTUs) of the red invasive seaweed Asparagopsis were assessed by studying introduced Mediterranean and Hawaiian populations. Invasive behavior of each Asparagopsis OTU was inferred from phylogeographic reconstructions, past historical demographic dynamics, recent range expansion assessments and future distributional predictions obtained from demographic models. Genealogical networks resolved Asparagopsis gametophytes and tetrasporophytes into four A. taxiformis and one A. armata cryptic OTUs. Falkenbergia isolates of A. taxiformis L3 were recovered for the first time in t…

Species–area relationship and small-island effect of vascular plant diversity in a young volcanic archipelago

2021

International audience; Aims: Aeolian islands form an active volcanic archipelago. By using updated vascular plant checklists for islands and islets, we tested four hypotheses: (i) Island speciesarea relationship (ISAR) of alien species has lower c-and higher z-values than native species, (ii) islands with active volcanoes have lower species richness than expected for native and alien species, (iii) ISAR of native species shows lower c-and higher z-values than ISARs of Mediterranean land bridge archipelagos and (iv) species richness of smaller islets is independent of area.Location: Aeolian Archipelago, Mediterranean Basin.Taxon: Vascular plants, identified and named according to the Flora …

Plant invasions on small Mediterranean islands. An overview

2016

Biological invasions have become one of the main drivers of habitat degradation and a leading cause of biodiversity loss in island ecosystems worldwide. The spread of invasive species poses a particular environmental threat on the islands of the Mediterranean Basin, which are hot spots of biodiversity and contain rare habitats and endemic species, especially on small islands, which are highly vulnerable to biodiversity loss. Following a recent survey, in this paper we aim to provide an overview of the present-day non-native vascular flora of small Mediterranean islands based on a sample of 37 islands located in the middle of the Mediterranean Sea, off the coast of Italy. By comparing the cu…

First successful eradication of invasive Norway rats Rattus norvegicus from a small Mediterranean island (Isola delle Femmine, Italy)

2019

Invasive alien species, once introduced, may affect local biodiversity, both directly (e.g. by predation) and indirectly (e.g. by reducing the vegetation cover). Among those, rats (Rodentia, Muridae) are listed among the most invasive species, exerting strong impacts particularly when introduced to island ecosystems. Accordingly, black rats Rattus rattus have been eradicated from a number of islands in the Mediterranean basin to protect breeding seabirds. Where the larger Norway rat Rattus norvegicus is present, extent of damage may be even higher. In our work, we present the results of the first eradication program dealing with Norway rats in a small Mediterranean island (Isola delle Femmi…

2016

By altering or eliminating delicate ecological relationships, non-indigenous species are con- sidered a major threat to biodiversity, as well as a driver of environmental change. Global cli- mate change affects ecosystems and ecological communities, leading to changes in the phenology, geographic ranges, or population abundance of several species. Thus, predicting the impacts of global climate change on the current and future distribution of invasive species is an important subject in macroecological studies. The African clawed frog (Xenopus laevis), native to South Africa, possesses a strong invasion potential and populations have become established in numerous countries across four contin…