Damage caused by the American grey squirrel (Sciurus carolinensis) to agricultural crops, poplar plantations and semi-natural woodland in Piedmont, Italy     

Signorile  Anna Lisa; Evans  Julian 《Forestry》2007,80(1):89-98

The incidence of damage caused by grey squirrels in the Turinplain was studied to assess the impact this alien species ishaving on the highly fragmented Piedmont environment, in particularon profitable cereals, poplar plantations and semi-natural woodlands.The survey of damage was conducted both by interviews to localfarmers and growers and by direct assessment using the NearestNeighbour Method on plantations and woodlands, studying randomlychosen plots in the Turin plain to gain a general overview ofthe situation. The results show a low incidence of damage causedby grey squirrels in the area: little or none was found in semi-naturalwoodlands and in agricultural crops, apart from maize whereless than 1 per cent of fields showed damage, and poplar plantationswhere 5 per cent had signs of bark stripping. Damage on maizecrops was random across the plain, but debarking damage to poplarswas mostly concentrated on the western side of the plain, andtended to occur only in particular years. Damage was concentratedclose to streams and rivers surrounding fields and plantations.The introduction of the grey squirrel in Italy has already causedecological damage such as the extinction of the red squirrelin some areas. Nevertheless, little or no information is availableon the damage this species is causing on woodlands or agriculturalareas. This study is a preliminary survey in order to fill thisgap.  相似文献   

Soil carbon distribution and quality in a montane rangeland-forest mosaic in northern Utah     

Helga Van Miegroet  Janis L. Boettinger  Michelle A. Baker  Julia Nielsen  Dave Evans  Alex Stum 《Forest Ecology and Management》2005,220(1-3):284-299

Relatively little is known about soil organic carbon (SOC) dynamics in montane ecosystems of the semi-arid western U.S. or the stability of current SOC pools under future climate change scenarios. We measured the distribution and quality of SOC in a mosaic of rangeland-forest vegetation types that occurs under similar climatic conditions on non-calcareous soils at Utah State University's T.W. Daniel Experimental Forest in northern Utah: the forest types were aspen [Populus tremuloides] and conifer (mixture of fir [Abies lasiocarpa] and spruce [Picea engelmannii]); the rangeland types were sagebrush steppe [Artemisia tridentata], grass-forb meadow, and a meadow-conifer ecotone. Total SOC was calculated from OC concentrations, estimates of bulk density by texture and rock-free soil volume in five pedons. The SOC quality was expressed in terms of leaching potential and decomposability. Amount and aromaticity of water-soluble organic carbon (DOC) was determined by water extraction and specific ultra violet absorbance at 254 nm (SUVA) of leached DOC. Decomposability of SOC and DOC was derived from laboratory incubation of soil samples and water extracts, respectively.

Although there was little difference in total SOC between soils sampled under different vegetation types, vertical distribution, and quality of SOC appeared to be influenced by vegetation. Forest soils had a distinct O horizon and higher SOC concentration in near-surface mineral horizons that declined sharply with depth. Rangeland soils lacked O horizons and SOC concentration declined more gradually. Quality of SOC under rangelands was more uniform with depth and SOC was less soluble and less decomposable (i.e., more stable) than under forests. However, DOC in grass-forb meadow soils was less aromatic and more bioavailable, likely promoting C retention through cycling. The SOC in forest soils was notably more leachable and decomposable, especially near the soil surface, with stability increasing with soil depth. Across the entire dataset, there was a weak inverse relationship between the decomposability and the aromaticity of DOC. Our data indicate that despite similar SOC pools, vegetation type may affect SOC retention capacity under future climate projections by influencing potential SOC losses via leaching and decomposition.  相似文献   

The effects of within-species and between-species variation in wood density on the photodegradation depth profiles of sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa)     

Yutaka Kataoka  Makoto Kiguchi  Takeshi Fujiwara  Philip D. Evans 《Journal of Wood Science》2005,51(5):531-536

Low density wood is more rapidly eroded than denser wood when exposed to the weather, possibly because it is more susceptible to photodegradation. Fourier transform infrared microscopy was used to examine: (1) the depth of photodegradation in earlywood and latewood of sugi (Japanese cedar) and earlywood of hinoki (Japanese cypress) exposed for up to 1500 h to artificial sunlight emitted by a xenon lamp (375 W/m² within the 300 to 700 nm spectral range); and (2) the relationship between the density of wood tissues and depth of photodegradation. The depth of photodegradation varied between species (sugi and hinoki) as well as within a growth ring (sugi earlywood and latewood), and there was an inversely proportional relationship between depth of photodegradation and wood density. These findings may explain why low density earlywood is more rapidly eroded than latewood during weathering, and more generally, why there is an inverse relationship between the density of wood species and their rate of erosion during artificial and natural weathering. Part of this work was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004  相似文献   

Evaluation of Meniscal Click for Detecting Meniscal Tears in Stifles with Cranial Cruciate Ligament Disease          下载免费PDF全文

Brittany A. Neal VMD  Dennis Ting DVM  Diplomate ACVS  Jennifer J. Bonczynski DVM  Diplomate ACVS  Koji Yasuda DVM 《Veterinary surgery : VS》2015,44(2):191-194

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Community‐based management of the environment: lessons from the past and options for the future     

S.M. Evans  A.C. Birchenough 《水产资源保护:海洋与淡水生态系统》2001,11(2):137-147

1. Traditional community‐based systems of managing coastal fisheries were (or in some cases are) successful in managing resources at sustainable levels. These systems are used as models in the present study. 2. They were (or are) under‐pinned by a sense of ownership and intimate knowledge of the environment in local people. 3. Such features have been largely lost, as subsistence economies have been replaced by capitalist ones, and environmental management responsibilities have shifted from local communities to national or international government. 4. There are, nevertheless, some examples of community‐based management systems that still operate successfully and we believe that modern management practices, in general, would benefit from increased community involvement. This will require renewed emphases on feelings of ownership and increased knowledge of the environment in the general public. 5. Environmental education will have a fundamental role to play in achieving this goal. However, its impact in schools and universities has been disappointingly ineffective so far in promoting a population that is sufficiently knowledgeable and well‐motivated to partake meaningfully in environmental management processes. 6. It is argued that educational initiatives, which involve all ages and sections of society, are required. Five promising possibilities are: (i) the participation of community groups in scientific projects; (ii) increased emphasis on life‐long learning; (iii) educational campaigns; (iv) citizens' juries; and (v) the involvement of community groups in environmental planning and management processes. 7. Wide‐scale adoption of innovations of these kinds will require funding and this will be achieved only by national re‐assessments of educational needs and priorities. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

In Reply to Symptomatic Hypotonic Hyponatremia Presenting at High Altitude     

Susanne J. Spano  Zacharia Reagle  Timothy Evans 《The Forestry Chronicle》2014,25(3):363-364

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Yields of cultured Pacific oysters Crassostrea gigas Thunberg improved after one generation of selection     

Chris Langdon  Ford Evans  Dave Jacobson  Michael Blouin 《Aquaculture (Amsterdam, Netherlands)》2003,220(1-4):227-244

Parental families (G₀) in three lines of Pacific oysters were selected based on live weight and meat yields at harvest. The average live weight yield of progeny (G₁) from crossing G₀-selected lines in seven trials was 9.5% greater than that of nonselected control families and live weight yields were significantly greater (ANOVA, P<0.001) in four out of seven trials. The response to selection was greater if G₁ families were tested at the same site as their parents' selection site rather than at a different site, although this effect was only significant for G₁ families of cohort 5 (P<0.01) but not cohort 7 (P>0.05). A significant genotype×environment interaction affected yields in both cohort 5 and cohort 7 (ANOVA; P<0.001). In addition, correlation between the yields of the same families planted at both intertidal and subtidal sites was positive but weak (cohort 5, r=0.30; cohort 7, r=0.35), indicating that selection for high yield in one environment would likely result in a low correlated response in a different environment. Nonetheless, it was possible to identify six families in cohort 5 and four families in cohort 7 that were among the top 10 families at both sites. Further evaluation of families across a wider range of environments is needed to determine if it is possible to substantially improve yields by selecting “generalist” families that perform well along the whole Pacific coast, or whether it will be necessary to select lines that are suited to particular sites.  相似文献   

News from the IAWS     

Robert Evans 《Wood Science and Technology》2014,48(2):225-226

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Efficacy of ceftiofur hydrochloride for treatment of experimentally induced colibacillosis in neonatal swine   总被引：2，自引：0，他引：2  

R J Yancey  R A Evans  D D Kratzer  J B Paulissen  S G Carmer 《American journal of veterinary research》1990,51(3):349-353

Ceftiofur hydrochloride was tested for effectiveness against induced colibacillosis in neonatal swine. In this model, pigs less than 12 hours old were inoculated via stomach tube with a virulent, K99+, nalidixic acid-resistant strain of Escherichia coli. Six hours after challenge exposure, 1 dose of ceftiofur was administered either IM or orally in experiment 1 and orally only in experiment 2. Mortality, shedding of bacteria, fecal consistency scores, and body weight changes were monitored for 10 days. In experiment 1 (n = 383 pigs), all treatments at dosage that ranged between 0.5 and 64.0 mg of ceftiofur/kg of body weight significantly (P less than 0.001) reduced mortality, bacterial shedding, and diarrhea and increased weight gain, compared with findings in untreated controls. There were no detectable differences between oral and IM routes, except that there was greater reduction in bacteria shedding associated with the oral route of administration. In experiment 2 (n = 505 pigs), ceftiofur was administered orally either once at 6 hours after challenge exposure or twice at 6 and at 48 hours after the first dose. Dosage of ceftiofur was 0, 5, 10, 20, 30, or 60 mg/kg administered once, or half the same dose was administered at each of 2 times. At the optimal dosage (10 mg/kg), a single dose was as effective as 2 doses. The single administration at all dosages reduced mortality, bacterial shedding, and diarrhea scores and increased body weight gain, compared with findings in untreated pigs (P less than 0.01). In this induced infection model, the optimal treatment dosage was determined to be 10 mg/kg administered once.  相似文献   

Identification of common antigens in ribosome-rich extracts from Fusobacterium necrophorum     

J N Berg  J W Evans 《American journal of veterinary research》1985,46(1):127-131

Ribosome-rich extracts (RRE) were prepared by differential and ultracentrifugation from 25 bovine and 6 ovine isolates of Fusobacterium necrophorum (FN) including both biotypes A and B. A pooled rabbit antiserum was prepared against whole-cell and sonicated whole-cell bacterins of F necrophorum isolate FN 3080, and a 2nd pooled rabbit antiserum was prepared against a RRE of FN 3080. The RRE of the 25 bovine isolates were tested against the FN 3080 whole-cell antiserum, using Ouchterlony double-immunodiffusion procedures. One to 3 precipitin lines were observed with the 25 isolates. The individual bovine isolates were found to have lines of identity with 5 to 21 of the other 24 isolates. The 25 bovine isolates and the 6 ovine isolates were then compared, using the FN 3080 RRE antiserum. One to 3 precipitin lines were observed for the 31 isolates with the RRE antiserum, and lines of identity were observed between all 31 of the isolates. These results indicated that common antigens are present in the RRE from a wide variety of F necrophorum isolates including both A and B biotypes.  相似文献