Search results for "Exotic species"
showing 7 items of 7 documents
Parasites in sympatric populations of native and invasive freshwater bivalves
2021
An increasing threat to local, native freshwater mussels (Unionida)—an ecologically important but globally alarmingly declining group— is the invasion by exotic bivalves. The Enemy Release Hypothesis predicts that introduced species should benefit from enemy-mediated competition because they are less likely to be harmed by natural enemies, such as parasites, than their native competitors. We investigated within-site differences in parasitism between sympatric native (tot. five spp.) and invasive (tot. three spp.) bivalves in eight northern European waterbodies, which harboured totally 15 parasite taxa. In paired comparisons using within-site averages, the mean number of parasite species in …
I rimboschimenti di cedro dell’Atlante [Cedrus atlantica (Endl.) Manetti ex Carrière] in Sicilia
2012
Il cedro dell’Atlante [Cedrus atlantica (ENDL.) MANETTI EX CARRIÈRE], introdotto in Europa come pianta ornamentale, ha trovato largo impiego nei rimboschimenti in Francia, Spagna e Portogallo, mentre in Italia la sua diffusione è stata più recente e a oggi interessa oltre 2600 ettari, dimostrando ottime potenzialità, senza comportamenti invasivi. In Sicilia, benché poco diffusa, la specie sembra avere potenzialità di adattamento e di produzione interessanti. Il presente lavoro prende in considerazione 7 popolamenti di cedro dell'Atlante dislocati in ambiti diversi rappresentativi delle condizioni ambientali locali, compatibili con le esigenze ecologiche della specie, tra questi un rimboschi…
Host manipulation of a freshwater crustacean (Gammarus roeseli) by an acanthocephalan parasite (Polymorphus minutus) in a biological invasion context.
2006
8 pages; International audience; Several gammarid species serve as intermediate hosts for the acanthocephalan parasite Polymorphus minutus. This parasite influences gammarid behaviour in order to favour transmission to its ultimate host, generally a bird. We investigated this host manipulation in Gammarus roeseli, a gammarid species introduced in France 150 years ago which now coexists with several exotic species from different origins. In the field, vertical distribution of G. roeseli revealed a higher proportion of infected individuals close to the water's surface and the size distribution of infected gammarids revealed predation pressure on infected individuals. However, under laboratory…
Les reboisements en cèdre de l’Atlas en Sicile
2013
Atlas cedar plantations in Sicily Atlas cedar (Cedrus atlantica) has been widely diffused in reforestation in Europe, particularly in France. In Italy, the Atlas cedar covers about 2600 ha. This paper examines 7 cedar plantations in Sicily, in the various typical condition of the island, evaluating their dendrometric characters in order to estimate productivity and growth capacity. The results show that this specie is both highly suitable for wood production, and has a landscape restoration role in difficult ecological conditions such as the Mediterranean mountain environment is. The stands production is comparable with the better results reported for the French plantations. Some cultivatio…
Artificial dam lakes as suitable habitats for exotic invertebrates: Ostracoda ecology and distribution in reservoirs of the Eastern Iberian Peninsula
2014
Reservoirs are the most common deep lakes in Spain, as a consequence of water needs and dry climate. Although these aquatic systems can play an important ecological role in such an area with few large natural lakes, they can also provide new habitats for exotic species, which can colonize ecosystems that native species have not explored yet. Here we present our results for a biannual survey of the ostracod fauna from 24 reservoirs in Xuquer River basin. We check which variables affect ostracod presence, test for differences between winter and summer assemblages, and compare our data with previous available ostracod records from the same river drainage network. Our results reveal that ostrac…
New Data on Native and Alien Vascular Flora of Sicily (Italy): New Findings and Updates
2023
In this paper, based on fieldwork and herbaria surveys, new data concerning the presence of 32 native and alien vascular species for Sicily (Italy) are provided. Among the native species, the occurrence of the following taxa is reported for the first time or confirmed after many decades of non-observation: Aira multiculmis, Arum maculatum, Carex flacca subsp. flacca, Mentha longifolia, Oxybasis chenopodioides, Najas minor and Xiphion junceum. Furthermore, we document the presence of three native species (Cornus mas, Juncus foliosus and Limonium avei) that, despite being repeatedly observed in Sicily and reported in the literature, are inexplicably omitted by the most recent authoritative ch…
Ecologia d'ostracodes simbionts (Entocytheridae) de carrancs invasors a Europa
2014
Els entocitèrids són una família d'ostracodes (Crustacea) ectosimbionts (bàsicament comensals) d'altres crustacis, majoritàriament decàpodes d'aigua dolça. Gran part de les espècies d'entocitèrids són originàries d'Amèrica del Nord i Central, i d'Oceania, associades a carrancs de riu americans i australians. No s'han descobert espècies d'entocitèrids en els carrancs de riu natius d'Europa. Les darreres dècades, els carrancs natius europeus s'han vist greument perjudicats per la invasió de carrancs exòtics, degut a fenòmens d'exclusió competitiva i transmissió de simbionts parasitaris. En la present tesi, hem avaluat la presència d'entocitèrids associats a carrancs de riu (natius i exòtics) …