Restricted access to private properties limits management of invasive alien species: A literature review and case studies.

Biological invasions are one of the major drivers of global environmental change and there is a need to develop integrated strategies to counteract this phenomenon. Eradication is an effective management option to mitigate the deleterious impacts of invasive alien species (IAS). Eradication can be achieved if all reproductive individuals are removed and population recovery is prevented. However, individuals may survive removal operations in private areas if interventions are not allowed. Here, we present 1) three case studies in which restricted private property access prevented the local eradication of invasive alien populations, and 2) a list of reasons for denying access to private properties and a list of actions implemented or suggested by managers to facilitate access and reported in 29 reviewed papers. The restricted access affected the local eradication of three Eastern grey squirrel (Sciurus carolinensis) populations in Italy. In Lombardy region, in one area a planned eradication did not start and in another area the implemented eradication failed due to the refusal from the owner of a large private property to grant access to managers. In Umbria region, the lack of collaboration from an Italian financial institution produced a delay of 15 months in the removal. In our case studies, therefore, a single person or institution denied access for a personal gain or presumed internal security. The reasons behind landowner opposition may be diverse and individual attitudes towards IAS management will depend on interactions with owners. According to our review, in many cases the denial of access takes place in a general perception of mistrust or opposition to the project as the results of a limited engagement of local people. Such opposition often jeopardizes control activities, with profound negative consequences on eradication, expecially at landscape scale. Bottom-up approaches aiming at involving stakeholders can increase the possibility to achieve IAS eradication, however appropriate legislation remains pivotal to enforce eradication in case of non-cooperative behaviour.

Long-term follow-up of cystic thyroid nodules treated with percutaneous ethanol injection (PEI) using two different approaches.

BACKGROUND AND AIM: Cystic thyroid nodules (CNs), although generally benign, can cause compressive or aesthetic problems. Percutaneous ethanol injection (PEI) can represent an alternative to surgery. The present retrospective study evaluates: (i) the long-term outcome of CNs after PEI; (ii) the differences between two different PEI protocols; (iii) the CNs response according to the liquid component. MATERIALS AND METHODS: The study comprises 358 nodules post-PEI followed for at least 2 years. PEI was performed according to two different treatment protocols with a single (Foggia) or double (Turin) alcohol injection. CNs were divided according to their composition: cystic (CYS) >90%, mainly cystic (M-CYS) 75-90%, mixed (MIX) 50-75%, solid-mixed (S-MIX) 35-50%. The volume reduction rate (VRR) was defined as nodule volume (mL) after PEI/nodule volume (mL) before PEI x 100. RESULTS: The 1-year VRR was significantly higher than that at 6 months (89.5% vs 72.9%, P = 0.0005), no differences were observed after 1 year. A significant difference between Turin and Foggia was observed only in VRR at early visit (79% vs 86%, respectively, P = 0.002) and recurrence rate (14% vs 24%, respectively, P = 0.001). Minor side-effects were infrequent. In 192 nodules with a 10-year follow-up CYS showed higher VRR than MIX and S-MIX nodules (P < 0.001). CONCLUSION: Our study reported that the long-term outcome of CNs treated with PEI is excellent regardless of the PEI technique utilized; the larger the cystic amount, the higher the VRR. Based on present results, PEI can be considered as the first-line choice for treating thyroid CNs.

Nickel, manganese and copper removal by a mixed consortium of sulfate reducing bacteria at a high COD/sulfate ratio.

The use of sulfate-reducing bacteria (SRB) in passive treatments of acidic effluents containing heavy metals has become an attractive alternative biotechnology. Treatment efficiency may be linked with the effluent conditions (pH and metal concentration) and also to the amount and nature of the organic substrate. Variations on organic substrate and sulfate ratios clearly interfere with the biological removal of this ion by mixed cultures of SRB. This study aimed to cultivate a mixed culture of SRB using different lactate concentrations at pH 7.0 in the presence of Ni, Mn and Cu. The highest sulfate removal efficiency obtained was 98 %, at a COD/sulfate ratio of 2.0. The organic acid analyses indicated an acetate accumulation as a consequence of lactate degradation. Different concentrations of metals were added to the system at neutral pH conditions. Cell proliferation and sulfate consumption in the presence of nickel (4, 20 and 50 mg l(-1)), manganese (1.5, 10 and 25 mg l(-1)) and copper (1.5, 10 and 25 mg l(-1)) were measured. The presence of metals interfered in the sulfate biological removal however the concentration of sulfide produced was high enough to remove over 90 % of the metals in the environment. The molecular characterization of the bacterial consortium based on dsrB gene sequencing indicated the presence of Desulfovibrio desulfuricans, Desulfomonas pigra and Desulfobulbus sp. The results here presented indicate that this SRB culture may be employed for mine effluent bioremediation due to its potential for removing sulfate and metals, simultaneously.

The consequences of introducing non-indigenous species: two case studies, the grey squirrel in Europe and the brushtail possum in New Zealand.

Two examples of the introduction of non-indigenous invasive species are reviewed: the grey squirrel in Europe (United Kingdom, Ireland and Italy) and the brushtail possum in New Zealand. Both have become very successful in their respective non-native habitats since their introductions in the mid-to-late 19th Century. Both species impact extensively on native biodiversity, environmental sustainability, forestry, and agriculture through a range of direct and indirect mechanisms. Management is currently mainly by lethal control, namely poisoning, trapping and shooting. Such methods of control are, however, increasingly contentious for both species, and alternative, non-lethal methods of population control, e.g. fertility control, are being developed. The case studies highlight many of the issues in invasive animal control; for example, prevention being better than control, lack of good understanding of impacts and the success of control measures on reducing impacts, interactive impacts on native biodiversity and ecosystems, the telling influence of public opinion on management options and, lastly, the need to better inform and educate the public.

Richness, origin and structure of an Eimeria community in a population of Eastern cottontail (Sylvilagus floridanus) introduced into Italy.

The composition and structure of a community of Eimeria was investigated in a population of Eastern cottontail (Sylvilagus floridanus) introduced into Italy. Eight Eimeria species were found, of which all but 1 had North American origins and were presumably introduced into Italy together with imported cottontails. The success of cottontails in spreading microparasites is probably related to their massive release for hunting purposes. Nearly all cottontails were infected with at least 1 Eimeria species, with bimonthly prevalence ranging from 0-6.3% (E. leporis) to 42.9-89.3% (E. environ). Bayesian model averaging and multivariate techniques were used to investigate the relationships between the occurrence of each parasite and the structure of the relative community. Among the host parameters, only sex was found to be associated with the prevalence of E. honessi, while the rest of the parameters were only weakly correlated with prevalence and species richness. This indicates that individual phenotypic host characteristics are probably less important than environmental factors in determining levels of parasite prevalence and diversity. The community of Eimeria species was probably structured by competition, with less species co-occurrence than expected under a null hypothesis. This was made evident by the low co-occurrence of E. environ and E. neoirresidua with E. poudrei, E. honessi, and E. maior.

Methodology for processing backscattered electron images. Application to Aguada archaeological paints.

Scanning electron microscopy is a powerful technique in several fields of science and technology. In particular it is an important complement in the characterization of materials for which X-ray analysis is not possible. Such is the case of thin paint layers on ceramic pots, in which, even for low incident energies, the electron interaction volume can be greater than the paint thickness--in addition to the problem arising from similar compositions. With the aim of complementing other common techniques used in compositional materials characterization, in this work, an image-processing software has been developed, which implements a new methodology for the treatment of backscattered electron (BSE) images in order to bring to evidence small mean atomic number contrasts, usually imperceptible to human eye. The program was used to study black and white pigments of ceramic pieces belonging to the Ambato style of "Aguada" culture (Catamarca province, Argentina, IV-XII centuries AD). Although the BSE images acquired for these samples showed no apparent contrast between sherd and black and white pigments, through image-processing algorithms using different space filters, chemical contrast between regions has been brought to evidence with a minor detail loss. This has been accomplished by applying a smoothing filter, after which the main routine for contrast enhancement reveals details in the grey-level region of interest; finally, a filter for edge enhancement permits to recover some details lost in the previous steps, achieving satisfactory results for the painted sherd samples analyzed. In order to validate the mean atomic number differences found between each pigment and the ceramic body, X-ray diffraction diagrams have been refined with Rietveld method using the software DIFFRACplus Topas, arriving to mineralogical differences which agree with the results obtained. As a consequence of this study, the program developed has proven to be a suitable tool for routine analysis of samples with slight chemical contrast.

Eimeria species (Apicomplexa: Eimeriidae) infecting Eliomys quercinus in an Alpine habitat.

Coccidian parasites were detected in an Alpine population of the garden dormouse (Eliomys quercinus), and 55-82% of the fecal samples collected during a two-year study (2000 and 2002) contained one or two eimerian species. We report the presence of Eimeria myoxi and confirm for the first time the presence of Eimeria melanuri in the garden dormouse. These Eimeria species can be considered common parasites of the garden dormouse and the Asian garden dormouse. The high prevalence might be due to group hibernation by the dormice.

Modulation of arachidonic acid release and membrane fluidity by albumin in vascular smooth muscle and endothelial cells.

Albumin is the major plasma protein circulating in blood. Albumin potently decreases capillary permeability, although the mechanisms are not understood completely. Albumin also effectively binds arachidonic acid (AA), which increases capillary permeability. To investigate the interactions of BSA and AA with the cell membrane, the effect of these substances on [3H]AA release and membrane fluidity was studied in vascular myocytes and endothelial cells. BSA (0.2 and 1 mg . mL-1) stimulated a significant release of [3H]AA from both intact rat aorta and cultured smooth muscle cells. This effect was not mimicked by gamma-globulin or myoglobin (both 1 mg . mL-1) in intact tissue. BSA, but not gamma-globulin and myoglobin, decreased the membrane fluidity (assessed as changes in the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3, 5-hexatriene) in a concentration-dependent manner with a half-maximum concentration between 0.007 and 0.4 mg . mL-1 in both freshly isolated and cultured rat aortic myocytes and human umbilical vein endothelial cells. AA (1 to 200 micromol/L) caused the opposite effect, increasing membrane fluidity and antagonizing the effect of BSA. BSA modified at its arginine residues, which are thought to be important in AA binding, did not stimulate [3H]AA release and was significantly less potent than native BSA in altering the membrane fluidity. The effect of BSA can be explained by a high-affinity binding of AA to the protein and extraction of AA from the cell membrane. The interaction between BSA and AA could play a role in the regulation of vascular permeability.

Renin secretion in Lyon hypertensive rats.

In genetically hypertensive rats of Lyon strain (LH), both development and maintenance of hypertension are extremely sensitive to the chronic blockade of the renin-angiotensin system. However, LH rats exhibit a low renin secretory profile as indicated by (1) low basal plasma renin concentration; (2) blunted renin responses to reductions of renal perfusion pressure and beta-adrenoceptor stimulation both in vitro (isolated perfused kidney) and in vivo (conscious rat). None of the latter abnormalities are corrected by chronic sodium deprivation or when hypertension is prevented by hydralazine or perindopril treatment. Future studies will therefore have to elucidate the 'renin paradox' in LH rats.

Renin secretion in conscious Lyon hypertensive rats.

To characterize the renin secretory profile in Lyon hypertensive (LH) rats, renin responses to reductions of arterial pressure and beta-adrenoceptor stimulation were assessed in conscious unrestrained LH (n = 13) and Lyon normotensive (LN, n = 14) rats under normal-salt diet. Mean arterial pressure (MAP) in the infrarenal aorta was recorded beat to beat for 3 h. Then, plasma renin concentration (PRC) was measured 1) in basal conditions, 2) during 10-mmHg stepwise reductions of MAP down to 60 mmHg using a chronically implanted aortic inflatable cuff, and 3) during isoprenaline infusion (62.5, 125, and 250 ng.kg-1.min-1 iv). Compared with LN, LH rats had an elevated MAP (146 +/- 3 vs. 111 +/- 1 mmHg, P < 0.001) and decreased PRC [4.2 +/- 0.6 vs. 8.2 +/- 0.8 ng angiotensin (ANG) I.ml-1.h-1, P < 0.001] and kidney renin content (216 +/- 14 vs. 1,149 +/- 103 micrograms ANG I.h-1.g-1, P < 0.001). Pressure-dependent renin release occurred below 90 mmHg in LN rats and below 80 mmHg in LH rats, and its sensitivity in the low-pressure range did not differ between strains. Isoprenaline-induced increases in PRC were weaker (P < 0.01) in LH than in LN rats. In additional LH and LN rats (n = 6-8), acute ANG II AT1-receptor blockade with losartan (20 mg/kg, followed by 10 mg.kg-1.h-1 iv for 2 h) induced lesser (P < 0.001) PRC increases in LH than in LN rats. Renin responses to isoprenaline remained blunted (P < 0.01) during losartan infusion in LH rats. We conclude that, in LH rats, renin secretion is independent of MAP in the range of its spontaneous variations and is poorly responsive to beta-adrenoceptor stimulation, the alteration of which cannot be explained by an enhanced feedback inhibition by ANG II.

Pressure control of renal renin release in Lyon hypertensive rats.

OBJECTIVE: To assess whether the pressure-independence of renin release by isolated kidneys of Lyon hypertensive (LH) rats could result from long-term exposure to high blood pressure, sodium retention or an altered regulation of intracellular calcium through L-type voltage operated channels. DESIGN: Renin release was studied in kidneys from LH rats, either controls or chronically (aged 3-7 weeks) treated with hydralazine or deprived of sodium. The influence of L-type calcium channels was studied acutely using a specific activator (BAY K8644) or modulator (verapamil). Lyon low blood pressure (LL) rats served as controls. METHODS: Kidneys were isolated from LH or LL rats aged 7 weeks and single-pass perfused at three pressure levels: 70, 85 and 160 mmHg. RESULTS: LH rat kidneys differed from LL rat kidneys in having elevated vascular resistances, decreased glomerular filtration rate, pressure natriuresis and pressure-dependent renin release. Hydralazine treatment and sodium deprivation did not significantly modify the pressure-independence of renin release by LH rat kidneys. BAY K8644 (1 x 10(-8) and 5 x 10(-8) mol/l) induced significantly greater vasoconstrictor effects in LH than in LL rat kidneys but did not affect the renin release already stimulated by low perfusion pressure. Verapamil (5 x 10(-6) mol/l) dilated LH more than LL rat kidneys. It did not change the renin release observed at low, but enhanced it at high, perfusion pressure. This effect was more marked in LL than in LH rat kidneys. CONCLUSIONS: The poor stimulation of renin release by low perfusion pressure in LH rat kidneys does not appear to be a consequence of high blood pressure level, sodium retention and alteration in L-type calcium channels. However, results demonstrate that these channels participate in the increased vascular resistances exhibited by LH rat kidneys.

Pressure-dependent renin release and arterial pressure maintenance in conscious rats.

The relationship between pressure-dependent renin release and mean arterial pressure (MAP) level was assessed in normotensive intact (n = 10), sympathectomized (guanethidine at 1-13 wk of age; n = 8), and renal-denervated (1 wk before the study; n = 6) rats under normal-salt diet. MAP was recorded beat-to-beat for 2 h in conscious animals. Then plasma renin concentration (PRC) responses to graded reductions of MAP were determined using an aortic inflatable cuff. Neither sympathectomy nor renal denervation altered baseline MAP level and PRC. Lowering MAP below a threshold pressure induced large increases in PRC. Threshold pressure did not differ between intact (87 +/- 1 mmHg), sympathectomized (88 +/- 2 mmHg), and renal-denervated (83 +/- 2 mmHg) rats. MAP frequently fell below threshold pressure in sympathectomized but not in intact and renal-denervated rats. We conclude that in conscious normotensive quiet rats under normal-salt diet the pressure-dependent renin release is not activated spontaneously and is therefore unlikely to play a role in MAP maintenance. This regulatory mechanism develops and operates normally in the absence of sympathetic nerves.