Historical land use and environmental determinants of nonnative plant distribution in coastal southern New England   总被引：1，自引：0，他引：1  

Betsy Von Holle  Glenn Motzkin 《Biological conservation》2007,136(1):33-43

The factors that influence the invasion of natural habitats by nonnative plants remain poorly understood. We investigated abiotic, biotic, and human influences on the distribution and abundance of nonnative species in coastal upland habitats of southern New England and adjacent New York, US. We censused vegetation and sampled soils in 776, 20 × 20 m plots in natural areas and constructed a spatially referenced GIS database of the region that included land-use history, distance from roads, and surficial geology. Our results indicate that the modern distribution of nonnative plants is influenced by multiple, interdependent current and historical factors. Glaciolacustrine landforms had greater nonnative species richness and cover than beach-dune, moraine, and glacial outwash sand plain landforms. Extant open-canopied areas (i.e., grasslands, dunes, heather barrens, and old fields) harbored significantly greater nonnative species richness and cover than closed-canopy forests, heathlands, and shrublands. Additionally, soil calcium levels and native species richness were positively associated with nonnative species richness. Sites that were cultivated historically or experienced other soil disturbance had higher nonnative species richness than areas without soil disturbance. Overall, abiotic, biotic and historical land use affected levels of nonnative species richness whereas nonnative cover was largely associated with abiotic conditions, particularly soil characteristics. Because many rare coastal sandplain plants reach their greatest abundance on extant open-canopied habitats, efforts to restore native plants will involve tradeoffs between the benefits of expanded habitat for these species and increased risk of invasion by nonnative species.  相似文献   

Historical influences on the vegetation and soils of the Martha’s Vineyard, Massachusetts coastal sandplain: Implications for conservation and restoration     

Christopher Neill  Betsy Von Holle  Katherine Kleese  Alexandra R. Colllins  Mary Dean 《Biological conservation》2007,136(1):17-32

Both disturbance history and previous land use influence present-day vegetation and soils. These influences can have important implications for conservation of plant communities if former disturbance and land use change species abundances, increase colonization of nonnative plant species or if they alter soil characteristics in ways that make them less suitable for species of conservation interest. We compared the plant species composition, the proportion of native and nonnative plant species, and soil biogeochemical characteristics across seven dominant land use and vegetation cover types on the outwash sandplain of Martha’s Vineyard that differed in previous soil tillage, dominant overstory vegetation and history of recent prescribed fire. The outwash sandplain supports many native plant species adapted to dry, low nutrient conditions and maintenance of native species is a management concern. There was broad overlap in the plant species composition among pine (Pinus resinosa, P. strobus) plantations on untilled soils, pine plantations on formerly tilled soils, scrub oak (Quercus ilicifolia) shrublands, tree oak (Q. velutina, Q. alba) woodlands, burned tree oak woodlands, and sandplain grasslands. All of these land cover categories contained few nonnative species. In contrast, agricultural grasslands had high richness and cover of nonnative plants. Soil characteristics were also similar among all of the woodland, shrubland and grassland land cover categories, but soils in agricultural grasslands had higher pH, extractable Ca²⁺ and Mg²⁺ in mineral soils and higher rates of net nitrification. The similarity of soils and significant overlap in vegetation across pine plantations, scrub oak shrublands, oak woodlands and sandplain grasslands suggests that the history of land use, current vegetation and soil characteristics do not pose a major barrier to management strategies that would involve conversion among any of these vegetation types. The current presence of high cover of nonnative species and nutrient-enriched soils in agricultural grasslands, however, may pose a barrier to expansion of sandplain grasslands or shrublands on these former agricultural lands if native species are not able to outcompete nonnative species in these anthropogenically-enriched sites.  相似文献   

Effects of isoflurane anesthesia on cerebrovascular autoregulation in horses     

Brosnan RJ  Steffey EP  LeCouteur RA  Esteller-Vico A  Vaughan B  Liu IK 《American journal of veterinary research》2011,72(1):18-24

  相似文献   

Intracranial dysfunctions: stupor and coma     

B Dayrell-Hart  A M Klide 《Veterinary Clinics of North America: Small Animal Practice》1989,19(6):1209-1222

Coma and stupor are pathologic neural states whose signs arise from either massive cortical or brainstem disease or toxicity. A variety of pathological processes can cause brain disease. Often one has to begin treatment before the diagnosis of the cause of the problem is made. At all stages of treatment, great care must be taken to avoid precipitating an intracranial crisis. The physiological derangements that may aid in the diagnosis include arousability, pupil reactivity, various reflexes, breathing patterns, and cardiovascular function. The treatment needs to be both specific and general; i.e., the condition itself must be treated, if possible, and the intracranial pressure must be lowered if it has been raised by the condition. Treatments for raised intracranial pressure include hyperventilation, diuretics, corticosteroids, avoidance of jugular vein compression, coughing, and any change of the position of the head and neck from normal. When sedating or anesthetizing these patients, one should avoid drugs that increase cerebral blood flow such as ketamine and inhaled anesthetics, using instead drugs that lower cerebral blood flow such as thiopental, lidocaine, and narcotics (with ventilation).  相似文献   

Diagnostic characterization of a feral swine herd enzootically infected with Brucella.     

William C Stoffregen  Steven C Olsen  C Jack Wheeler  Betsy J Bricker  Mitchell V Palmer  Allen E Jensen  Shirley M Halling  David P Alt 《Journal of veterinary diagnostic investigation》2007,19(3):227-237

Eighty feral swine were trapped from a herd that had been documented to be seropositive for Brucella and which had been used for Brucella abortus RB51 vaccine trials on a 7,100-hectare tract of land in South Carolina. The animals were euthanized and complete necropsies were performed. Samples were taken for histopathology, Brucella culture, and Brucella serology. Brucella was cultured from 62 (77.5%) animals. Brucella suis was isolated from 55 animals (68.8%), and all isolates were biovar 1. Brucella abortus was isolated from 28 animals (35.0%), and isolates included field strain biovar 1 (21 animals; 26.3%), vaccine strain Brucella abortus S19 (8 animals, 10.0%), and vaccine strain Brucella abortus RB51 (6 animals, 7.5%). Males were significantly more likely to be culture positive than females (92.9% vs. 60.6%). Thirty-nine animals (48.8%) were seropositive. Males also had a significantly higher seropositivity rate than females (61.9% vs. 34.2%). The relative sensitivity rates were significantly higher for the standard tube test (44.6%) and fluorescence polarization assay (42.6%) than the card agglutination test (13.1%). Lesions consistent with Brucella infection were commonly found in the animals surveyed and included inflammatory lesions of the lymph nodes, liver, kidney, and male reproductive organs, which ranged from lymphoplasmacytic to pyogranulomatous with necrosis. This is the first report of an apparent enzootic Brucella abortus infection in a feral swine herd suggesting that feral swine may serve as a reservoir of infection for Brucella abortus as well as Brucella suis for domestic livestock.  相似文献   

Cancer detection in clinical practice and using blood-based liquid biopsy: A retrospective audit of over 350 dogs     

Andi Flory  Lisa McLennan  Betsy Peet  Marissa Kroll  Deirdre Stuart  Devon Brown  Kathy Stuebner  Brenda Phillips  Brenda L. Coomber  J. Paul Woods  Mairin Miller  Chelsea D. Tripp  Amber Wolf-Ringwall  Kristina M. Kruglyak  Angela L. McCleary-Wheeler  Ashley Phelps-Dunn  Lilian K. Wong  Chelsea D. Warren  Gina Brandstetter  Michelle C. Rosentel  Lauren R. DiMarzio  Allison L. O'Kell  Todd A. Cohen  Daniel S. Grosu  Jason Chibuk  Dana W. Y. Tsui  Ilya Chorny  Jill M. Rafalko 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2023,37(1):258-267

  相似文献   

Effect of cholesterol-loaded cyclodextrin treatment of bovine sperm on capacitation timing     

Gerica LaVelle  Betsy Cairo  Jennifer P. Barfield 《Reproduction in domestic animals》2023,58(1):176-183

Pre-loading bovine sperm with cholesterol prior to freezing is known to increase cryosurvival, though the timing of capacitation in these sperm has not been evaluated. The objective of this study was to determine if there is a potential delay in capacitation timing in these sperm due to the increased cholesterol content. Flow cytometric evaluation was utilized to assess viability, and stain technology to assess acrosome intactness (Propidium Iodide/FITC-PNA), intracellular calcium levels (Propidium Iodide/FLUO 3-AM) and membrane fluidity (Merocyanine 540/YO-PRO-1). Cholesterol-loaded cyclodextrin (CLC) (2 mg/mL) improved post-thaw viability to 61% from 45% in control sperm (p < .05). The addition of ionomycin (0.05 mM) induced capacitation in sperm by 1 h, resulting in increased intracellular calcium and increased acrosome reaction, and consequently viability loss by 3 h. Treatment with CLC significantly decreased membrane fluidity in sperm (p < .05). In conclusion, CLC-treated sperm required 1 h more to capacitate when compared with non-treated sperm based on percentage of live cells with high membrane disorder (p < .05). Increased cryosurvival and viability over time was observed, but longer time to capacitate may hinder fertilization capacity and/or require adjustments to timing of in vitro fertilization.  相似文献   

Bartonella henselae IgG antibodies are prevalent in dogs from southeastern USA     

Solano-Gallego L  Bradley J  Hegarty B  Sigmon B  Breitschwerdt E 《Veterinary research》2004,35(5):585-595

In contrast to the large body of literature regarding Bartonella henselae in humans and cats, there is little information about B. henselae as an infectious agent in dogs. Due to the paucity of information regarding the B. henselae serology in dogs, we performed a cross-sectional serosurvey using B. henselae antigen in order to compare the seroprevalence between sick and healthy dogs from the south-eastern USA. Ninety-nine sera were collected from clinically healthy dogs. Three hundred and one sera from sick dogs were submitted to North Carolina State University for serologic screening against a panel of arthropod-transmitted organisms. Serological tests were performed using B. henselae (Bh), Rickettsia rickettsii (Rr), Ehrlichia canis (Ec), Bartonella vinsonii subspecies berkhoffii (Bvb), Babesia canis (Bc) and Borrelia burgdorferi (Bb) antigens. Serum B. henselae IgG antibodies were detected in 10.1% of healthy dogs and in 27.2% of sick dogs. The difference in seroprevalence between the two groups was statistically significant. The majority of seroreactive dogs (80%) had low titers of 1:64 or 1:128. In healthy dogs, seroprevalence for Rr was 14.1% and for Bvb was 1%. In sick dogs, Rr seroprevalence was 29.7%, Ec 6.5%, Bvb 4.7%, Bb 1.7% and Bc was 0.85%. Of the sick dogs that were seroreactive to B. henselae antigens, 40.6% were also seroreactive to Rr, 15.0% reactive to Bvb antigens, 14.8% reactive to Ec antigens, 1.8% reactive to Bc antigens and 1.75% reactive to Bb antigens. Sera from dogs experimentally infected with B. vinsonii subsp. berkhoffii, E. canis or R. rickettsii did not cross react with B. henselae antigens, by IFA testing. This study indicates that B. henselae IgG antibodies are prevalent in healthy and sick dogs living in the south-eastern USA. Nevertheless, further studies are needed to evaluate the epidemiological, clinical and zoonotic relevance of B. henselae infection in dogs.  相似文献   

Atrial fibrillation in cats: 50 cases (1979-2002)     

Côté E  Harpster NK  Laste NJ  MacDonald KA  Kittleson MD  Bond BR  Barrett KA  Ettinger SJ  Atkins CE 《Journal of the American Veterinary Medical Association》2004,225(2):256-260

OBJECTIVE: To determine signalment, clinical signs, diagnostic findings, treatment, and outcome for cats with atrial fibrillation (AF). DESIGN: Retrospective study. ANIMALS: 50 cats. PROCEDURE: Medical records of cats that met criteria for a diagnosis of AF (ECG consisting of at least 2 leads, clear absence of P waves, supraventricular rhythm, and convincingly irregularly irregular rhythm) and had undergone echocardiography were reviewed. RESULTS: There were 41 males (37 castrated) and 9 females (7 spayed). Forty-one were of mixed breeding; 9 were purebred. Mean +/- SD age was 10.2 +/- 3.7 years. The most common chief complaints were dyspnea, aortic thromboembolism, and lethargy. In 11 cats, AF was an incidental finding. Mean +/- SD ventricular rate was 223 +/- 36 beats/min. The most common echocardiographic abnormalities were restrictive or unclassified cardiomyopathy (n = 19), concentric left ventricular hypertrophy (18), and dilated cardiomyopathy (6). Mean +/- SD left atrial-to-aortic diameter ratio (n = 39) was 2.55 +/- 0.80. The most common thoracic radiographic findings were cardiomegaly, pleural effusion, and pulmonary edema. Median survival time (n = 24) was 165 days (range, 0 to 1,095 days). Eight of 24 cats lived for > or = 1 year after a diagnosis of AF was made. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that AF occurs primarily in older adult male cats with structural heart disease severe enough to lead to atrial enlargement. Atrial fibrillation in these cats was most commonly first detected when signs of decompensated cardiac disease were evident, but also was commonly identified as an incidental finding.  相似文献   

Experimental test of oyster restoration within eelgrass          下载免费PDF全文

Stephanie R. Valdez  Betsy Peabody  Brian Allen  Brady Blake  Jennifer L. Ruesink 《水产资源保护:海洋与淡水生态系统》2017,27(3):578-587