1,721,015 research outputs found
Condition Index (FCF) come strumento per la gestione e la conservazione di Austropotamobius pallipes complex
No full textQuantitative habitat models for the conservation of the endangered European crayfish Austropotamobius pallipes complex
No full textPresence of Branchiobdellida in five population of native crayfish in Northern Italy: preliminary results
No full textImpatto dell’ittiofauna alloctona sulla comunità autoctona nel reticolo idrografico minore del fiume Ticino
No full textL’introduzione di specie alloctone rappresenta la seconda minaccia alla conservazione della biodiversità a livello globale; ancora più gravi sono gli impatti negli ecosistemi d’acqua dolce. Le specie ittiche alloctone in Italia sono sensibilmente più numerose a quelle presenti in altri stati europei e la maggior parte delle immissioni è da ascriversi all’intervento umano. Lo scopo del seguente lavoro è quello di indagare gli effetti della competizione delle specie ittiche alloctone sulla componente autoctona. Sono state indagate 23 stazioni nella rete idrica minore del fiume Ticino nelle province di Varese, Milano e Novara, in cui sono state campionate 10 specie alloctone (n= 886) e 14 specie autoctone (n= 4179). Per valutare l’effetto della competizione sono state condotte analisi sia a livello di comunità sia a livello di singole specie. Le analisi hanno evidenziato una correlazione positiva significativa tra l’indice di diversità di Shannon delle comunità di specie autoctone e quello delle specie alloctone; ciò fa pensare che non vi siano effetti evidenti di competizione a livello di comunità. Questa correlazione è emersa anche tra l’abbondanza di Barbus barbus e la comunità di specie autoctone sia in termini di biomassa totale sia in numero di individui; mentre il numero di individui di Misgurnus anguillicaudatus correlava negativamente sia con la biomassa della comunità autoctona sia con la biomassa di Telestes muticellus. Questo risultato potrebbe essere spiegato da una maggiore resistenza di Misgurnus anguillicaudatus a fenomeni di carenza idrica, che possono verificarsi anche nell’area di studio
Considering the conditin index of populatins for the conservatin and management of Austropotamobius pallipes complex
No full textColour variation in signal crayfish Pacifastacus leniusculus
Full text linkExternal colouration in animals depends on the interaction of several different factors including the genetics and epigenetics processes that underlie the colour expression, the mechanisms of colour perception, and the general mechanisms controlling colour evolution and function. Among all, camouflage from predators and conspicuousness are of particular interest since pose animal to choose between opposite adjustment in colouration. The external colouration of crustaceans is mainly due to the accumulation of carotenoids in the exoskeleton and the epidermal layer, and the trade-off between camouflage and communication had lead to a variety of responses, involving signal partitioning, spectral sensibility, changing colouration or signalling behaviour. Here, we used digital images to explore intrapopulation variability of the external colouration of Pacifastacus leniusculus among body regions within an individual and between sexes. We found that i) ventral colouration of claws are more saturated and brilliant than upperparts, ii) males express a more saturated and brightness colouration than females, especially on the lower portion of claws, iii) colour intensity and brightness increases with size differently in different body regions, and iv) brightness is more variable in males than in females. All the above patterns support the hypothesis that colour in this species could be the result of a compromise between camouflage from predators and conspicuousness for communication. The results of this study suggest that carotenoid might have something to do with intraspecific communication and perform more complex functions than that of a simple pigment
Fast non-destructive assessment of heavy metal presence by ATR–FTIR analysis of crayfish exoskeleton
No full textHABITAT REQUIREMENTS OF THE ENDANGERED CRAYFISH AUSTROPOTAMOBIUS PALLIPES COMPLEX IN NORTHERN ITALY
No full textReproductive efficiency of Austropotamobius pallipes complex in experimental rearing centers, in relation to some individual measurements, to their original watercourses and to the reproduction year
No full textOur research aimed to collect data about fertility of Austropotamobius pallipes in order
to evaluate its reproduction effi ciency. From 2008 to 2012 two rearing centers formed
by outdoor pools were used as experimental farms and young crayfi shes produced
were used for reintroduction according to LIFE project CRAINat (LIFE08NAT/
IT/000352). Between September and October we caught 407 reproductive females
(activated glair glands). They originated from 17 watercourses of the Lombardy
pre-alpine zone. We have measured all the animals as concerns total length (from
the tip of the rostrum to the end of telson; average 77.07±8.38 mm) and weight
(average 13.15±4.26 g). They were individually marked. The whole rearing cycle
(mating, egg-bearing, hatching of juveniles) was conducted in semi-natural conditions
in the outdoor pools. In all the months of May we checked the egg-berried
females. In the fi ve years period we have obtained 40.8% of berried females. We
tested if reproductive effi ciency varied between females, rearing centers, the original
watercourses and the rearing years. To do this, we used a GLMM (generalized linear
mixed model) with binomial error in which the present or absent of egg-berried was
the response variable, the total length and the original watercourses were the fi xed
component, while the rearing years are the random one. The rearing year was the
only variable signifi cantly affecting the reproductive effi ciency of females (LR-χ2 =
6.543, df = 1, P = 0.010; σ2 = 0.23±0.48), since the probability to produce fertile
eggs resulted higher in 2008 and 2011 while the lowest occurred in 2009
Using PIT telemetry for long-term monitoring of Austropotamobius pallipes complex populatins in a conservatin program
No full textThe contiuing decline of Austropotamobius pallipes complex populatins and the endangered status of the species have driven to plan and develop several conservatin programmes. Following key elements of management strategies, we conducted a long-term populatin monitoring in order (i) to evaluate PIT tag retentin and effcts of tagging on survival of crayfih and (ii) to map crayfih shelters and movements in long-term monitorin
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