Spatial organisation and feeding ecology of the American mink (Mustela vison) in a coastal habitat

The American mink (Mustela vison Schreber) is the only introduced carnivore that has successfully colonised the British Isles. In the present study, the important problem of understanding which are the factors that limit or enhance their number has been addressed. A mink population (Mustela vison) inhabiting a coastal area of SW Scotland, was studied. The main purpose was to relate the spatial organisation of mink with spatial and temporal variations in the abundance and distribution of its prey, through the study of foraging strategies and habitat selection. Different scales of spatial organisation were considered. Foraging strategies (activity levels, habitat use, foraging behaviour) were found to vary over time and in areas with different habitat characteristics. The distribution and abundance of terrestrial prey was found to be important in determining such strategies, ultimately influencing mink densities. This observation supports the hypothesis of Clode and Macdonald (1995) on the influence of terrestrial prey on mink ability to disperse. Habitat selection of mink in the intertidal zone was studied here for the first time. Resident animals, which were foraging at low or mid tide, and within core areas were found to behave selectively, preferring areas with high prey abundance. In the intertidal zone, prey was most abundant in the lower shore, in areas without fresh water, and in areas with abundant and large rockpools. Mink showed preference for all these habitat characteristics. The nature of the substratum was also important in determining the abundance of prey out of rockpools. The results of this study are discussed in relation to limiting resources and competition with native carnivores. Finally a new home range estimator - the Density Circles method - was developed. This estimator is particularly suitable for describing home ranges presenting anomalous shapes, such as those found in mink

Decreased small mammals species diversity and increased population abundance along a gradient of agricultural intensification

Agricultural intensification has been widespread worldwide over the last decades and has lead to a loss of semi-natural habitats. These changes are likely to have affected both the composition and diversity of small mammal communities living in agricultural landscapes. In this context, we compared population abundance (expressed as an index of relative abundance), species richness (S), and species diversity (expressed as Shannon and Pielou indexes) of small mammal assemblages (i.e. sub-sets of the entire small mammal community) living in three areas in North-East Italy positioned along a gradient of agricultural land-use intensification (measured with the Landscape Conservation Index). We expected that assemblages would be less diverse and dominated by generalist species where the landscape was more intensely cultivated and where semi-natural habitats were less common. In the three areas, from a total of 4630 trap-nights, 668 individuals were captured with Sherman traps, belonging to four species (Apodemus agrarius, A. flavicollis, A. sylvaticus and Microtus arvalis). The results showed that population abundance, type of species present (but not species richness), and species diversity were affected by agricultural intensification and landscape naturalness. In particular, moving from less natural to more natural landscapes, we observed no effect on richness of species but increasing diversity due to a greater abundance of the more specialist species, such as A. agrarius and, partially, A. flavicollis, the latter only present in the most natural area. Generalist species, namely A. sylvaticus, and those associated with disturbed environments, such as M. arvalis, were instead more abundant in less natural landscapes. When considering population abundance, the highest overall abundance of small mammals was found in the most disturbed landscape. The results were consistent with those of research carried out in other agroecosystems of Europe and highlight the controversial effect of the anthropogenic impact on small mammal assemblages, since a decrease in species diversity may be associated with an increased overall population abundance, due to the success of few generalist species. \ua9 2014 Associazione Teriologica Italiana

Mono- and Bis-Alkylated Lumazine Sensitizers: Synthetic, Molecular Orbital Theory, Nucleophilic Index and Photochemical Studies

Mono- and bis-decylated lumazines have been synthesized and characterized. Namely, mono-decyl chain [1-decylpteridine-2,4(1,3H)-dione] 6a and bis-decyl chain [1,3-didecylpteridine-2,4(1,3H)-dione] 7a conjugates were synthesized by nucleophilic substitution (SN 2) reactions of lumazine with 1-iododecane in N,N-dimethylformamide (DMF) solvent. Decyl chain coupling occurred at the N1 site and then the N3 site in a sequential manner, without DMF condensation. Molecular orbital (MO) calculations show a p-orbital at N1 but not N3 , which along with a nucleophilicity parameter (N) analysis predict alkylation at N1 in lumazine. Only after the alkylation at N1 in 6a, does a p-orbital on N3 emerge thereby reacting with a second equivalent of 1-iododecane to reach the dialkylated product 7a. Data from NMR (1 H, 13 C, HSQC, HMBC), HPLC, TLC, UV-vis, fluorescence and density functional theory (DFT) provide evidence for the existence of mono-decyl chain 6a and bis-decyl chain 7a. These results differ to pterin O-alkylations (kinetic control), where N-alkylation of lumazine is preferred and then to dialkylation (thermodynamic control), with an avoidance of DMF solvent condensation. These findings add to the list of alkylation strategies for increasing sensitizer lipophilicity for use in photodynamic therapy.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Primi dati di distribuzione del visone americano (Neovison vison) nella provincia di Vicenza. First data on the distribution of the American mink in the Province of Vicenza

Natura Vicentin

A Model of Correlated Evolution

We introduce a model of biological evolution inspired by the Bak and Sneppen (BS) model. Microscopic dynamical rules are modified with respect to the BS model in order to account for predator-prey and competitor correlations. We perform numerical simulations of the system and compare them with both a mean field equation and a mean field simulation. The model is in a new universality class of self-organized critical behavior, and in addition shows a non-trivial fitness probability distribution. I. INTRODUCTION Much attention has recently focused upon non equilibrium systems displaying selforganized criticality (SOC), a concept introduced by P. Bak, C. Tang and K. Wiesenfeld [1]. SOC systems appear to be widespread in nature, including sandpiles [1], earthquakes [2], creep phenomena [3], material fracturing [4], fluid displacement in porous media [5], interface growth [6] and river networks [7]. Recently Bak and Sneppen (BS) [8,9] introduced a SOC model describing an ecosystem of interac..