Characterization of viral loads, strain and state of equine herpesvirus-1 using real-time PCR in horses following natural exposure at a racetrack in California     

Pusterla N  Wilson WD  Mapes S  Finno C  Isbell D  Arthur RM  Ferraro GL 《Veterinary journal (London, England : 1997)》2009,179(2):230-239

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Nutritive Quality of Highbush Blackberry (Rubus argutus) Exposed to Tropospheric Ozone     

Stephen S. Ditchkoff  John S. Lewis  John C. Lin  Russell B. Muntifering  Arthur H. Chappelka 《Strength and Conditioning Journal》2009,62(4):364-370

Numerous studies have examined the impacts of ground level O₃ on plants that are important for human consumption, but native species that are important for wildlife have received less scrutiny. During May–August 2004 we examined the effects of O₃ on biomass production and nutritive quality of highbush blackberry (Rubus argutus Link), an important forage for white-tailed deer (Odocoileus virginianus Zimmerman) and other herbivorous mammals. Plants were fumigated in open-top chambers with three levels of O₃ in a randomized-block experiment with three replicates of each treatment. Our three experimental treatments were carbon-filtered air, characteristic of clean air quality; nonfiltered air, representative of air quality in Auburn, AL; and air with double (2×) the ambient concentration of O₃. Although biomass production was not influenced by O₃ exposure, nutritive quality of plants was associated negatively with O₃ concentration. Specifically, neutral detergent fiber was greater and relative feed value was less in plants exposed to elevated levels of O₃. Similarly, in vitro dry matter digestibility tended to be less in plants exposed to elevated O₃. Nutritive quality of regrowth vegetation followed a similar pattern, where neutral detergent fiber was greater and relative feed value was less in plants exposed to elevated levels of O₃. These data suggest that elevated levels of ground level O₃ could have implications for diet selection of herbivorous mammals.  相似文献   

Noise reactivity in three breeds of herding dogs: What the crossroads of demography,ethology, and genetics can tell us     

Karen Overall  Steven P. Hamilton  Melanie Lee Chang  Jennifer S. Yokoyama  Donna J. Dyer  Arthur E. Dunham  Nicholas Branson  Soraya Juarbe-Diaz 《Journal of Veterinary Behavior: Clinical Applications and Research》2009,4(2):70-71

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Vulnerability to eutrophication of a semi-annual life history: A lesson learnt from an extinct eelgrass (Zostera marina) population     

Marieke M. van Katwijk  Arthur R. Bos  Peer Kennis 《Biological conservation》2010,143(1):248-254

A semi-annual eelgrass (Zostera marina L.) population became extinct in 2004. It had flourished for many decades at Terschelling in the western Wadden Sea, one of the most eutrophied locations where seagrass growth has been recorded. Semi-annual populations survive the winter season by seed (annual), and by incidental plant survival (semi-annual). We compared seed bank dynamics and fate of plants between this impacted site and a reference site in the winter of 1990-1991. Seed bank density at Terschelling was extremely low (5-35 seeds m⁻²) in comparison to the reference site (>60 seeds m⁻²) and also in comparison to seed bank densities of (semi-)annual eelgrass populations in other parts of the world. Plant survival during winter was nil. Nevertheless, the population more than doubled its area in 1991, implying maximum germination and seedling survival rates. However, from 1992 onwards the decline set in and continued - while the nutrient levels decreased. To establish the cause of the low seed bank density, we conducted a transplantation experiment in 2004 to study the relationship between seed production and macro-algal cover. The transplantation experiment showed a negative relationship between the survival of seed producing shoots and suffocation by macro-algae, which is associated with light limitation and unfavourable biogeochemical conditions. The plants died before they had started to produce seeds. Thus, it is likely that macro-algal cover was responsible for the low seed bank density found in Terschelling in 1990-1991. Both the recorded low seed bank density and absence of incidental plant survival during winter were related to eutrophication. These parameters must have been a severe bottleneck in the life history of the extinct population at the impacted site, particularly as Z. marina seed banks are transient. Therefore we deduce that this population had survived at the edge of collapse, and became extinct after a small, haphazard environmental change. We argue that its resilience during these years must have been due to (i) maximum germination and seedling survival rates and (ii) spatial spreading of risks: parts of the population may have survived at locally macro-algae-free spots from where the area could be recolonised. As a consequence, the timing of the collapse was unpredictable and did not synchronise with the eutrophication process. The lesson learnt for conservation is to recognise that eutrophication may be a cause for seagrass population collapse and its eventual extinction, even years after nutrient levels stabilised, or even decreased.  相似文献   

Legislation and the capacity for rapid‐response management of nonindigenous species of fish in contiguous waters of Canada and the USA     

Vernon G. Thomas  Charlotte Vásárhelyi  Arthur J. NIIMI 《水产资源保护:海洋与淡水生态系统》2009,19(3):354-364

• 1. The provision of Canadian and US hard, enforceable, law to authorize rapid response management of nonindigenous aquatic species originating from aquaculture, live fish sales, bait fish, and the pet trade was analysed at the provincial/state levels of government for the Atlantic, Laurentian Great Lakes, and Pacific regions of North America.
• 2. No federal legal capacity for rapid response management exists in either country. US state legislation is generally better developed than Canadian provincial laws to manage the exotic fish trade. However, much discrepancy exists among provincial and state law regarding provisions to restrict or prohibit potentially harmful species. Aquaculture and baitfish use is generally better regulated than live fish markets and the pet fish trade in both countries. Only the state of Maine has laws authorizing rapid‐response management to control escaped exotic fish.
• 3. Most species of nonindigenous fish arise from the aquarium, pet, and baitfish trades, and development of improved legislation containing provisions for rapid response management of escapees is warranted in all states and provinces.
• 4. It is recommended that Canada amends the Fisheries Act to create the appropriate enabling legislation to monitor, assess risk, and deploy rapid response management of nonindigenous aquatic species, including fish that enter federal fresh and sea waters. Two recently‐introduced US Bills, S. 725 and H.R. 1350, with their explicit measures for early detection and fast action response, could, if passed into law, create provisions to control introduced nuisance species throughout North American waters. They would also create precedents for states and provinces that have most jurisdiction over aquaculture and trade in exotic fish to amend and align their laws in a complementary manner.

Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Soybean expansion impacts on soil organic matter in the eastern region of the Maranhão State (Northeastern Brazil)     

Marcos Siqueira-Neto  Gustavo V. Popin  Gregori E. Ferrão  Arthur K. B. Santos  Carlos E. P. Cerri  Tiago O. Ferreira 《Soil Use and Management》2022,38(2):1203-1216

Recently, the eastern region of the Maranhão state (Northeastern Brazil) became a hotspot of land-use change (LUC) directly from native vegetation to soybean cultivation, but due to the soil characteristics, LUC has caused substantial soil organic carbon (SOC) and nitrogen depletion. Therefore, we quantified these impacts arising from two factors: (i) different timeframes after LUC and (ii) contrasting soil management practices. For the first study, soil samples (0–30 cm; six replicates) were taken on soybean fields year one, year eight and 15 years after LUC. It the second study, another area was sampled, of which part was managed under no-tillage (NT) and the other using a mouldboard plough (MP). For both studies, native vegetation (NV) was sampled as the control. NV stored about 50 Mg of carbon (C) ha⁻¹; but LUC reduced C stocks by 35% (after 8 and 15 years); moreover, labile-C decreased between 20% and 45%, while, microbial-C decreased between 20% and 60%, considering the interval between year one and 15 years. Regarding soil management, the MP did not cause differences on C stock (24 Mg C ha⁻¹) in comparison to NT; however, both labile-C and microbial-C decreased by 15% to NT, while, decreased by 40% to MP. These results lead us to believe that, since LUC is inevitable, we suggested the adoption of the best agricultural management practices, in order to preserve/increase the SOC, reducing the impacts on GHG emissions and, thus, achieving sustainability and profitability.  相似文献