Climate change impacts on stand structure and competitive interactions in a southern Swedish spruce–beech forest

It is believed that European beech (Fagus sylvatica L.) will increase its competitive ability at its northern range margin in Scandinavia due to climate change. In mixed old-growth forests of beech and Norway spruce (Picea abies (L.) Karst.) at Siggaboda nature reserve (southern Sweden), stand structure characteristics were sequentially recorded in the years 2004, 2005 and 2007 as well as growth in stem diameter using tree-coring analyses. Using these measurements, we studied the effects on stand dynamics of an extreme storm event (2005 “Gudrun” hurricane), drought and heat (mid-summer 2006, spring 2007) and subsequent bark beetle attacks on spruce (growing season 2007), overlaid with warming tendencies. The storm, which caused disastrous damage in many stands nearby, had comparatively little impact on the structure of the spruce–beech stand. All together, only 32 trees (19 spruces, 10 beeches, 3 other species) per hectare were thrown or broken mainly in the leeward direction (NE) or impacted by secondary damage by uprooted neighbour trees; this represents 7% of the total tree number and 11% of the growing stock. Diameter and height structure did not change significantly. However, the 2006 drought and the 2007 attack of biotic agents changed the stand structure and composition strongly due to the death of about 19% of the dominating older spruce trees that accounted for 35% of total stand volume. This resulted in a considerable increase in beech’s contribution to stem number (4% increase) and wood volume of the living stand (7% increase). A comparison of diameter growth of beech and spruce during the periods 1894–1949 and 1950–2005 showed a distinct decrease in growth superiority of spruce during the last 50 years. These results support the idea of a northward migration of European beech as a nemoral tree species in Sweden, due to a higher tolerance to the abiotic and biotic threats accompanying climate change and an increased competitive ability compared to boreal tree species Norway spruce.     

Reproductive Performance,Udder Health,and Antibiotic Resistance in Mastitis Bacteria isolated from Norwegian Red cows in Conventional and Organic Farming

Background

The objectives of this study were to investigate whether there were differences between Norwegian Red cows in conventional and organic farming with respect to reproductive performance, udder health, and antibiotic resistance in udder pathogens.

Methods

Twenty-five conventional and 24 organic herds from south-east and middle Norway participated in the study. Herds were matched such that geographical location, herd size, and barn types were similar across the cohorts. All organic herds were certified as organic between 1997 and 2003. All herds were members of the Norwegian Dairy Herd Recording System. The herds were visited once during the study. The relationship between the outcomes and explanatory variables were assessed using mixed linear models.

Results

There were less > 2nd parity cows in conventional farming. The conventional cows had higher milk yields and received more concentrates than organic cows. Although after adjustment for milk yield and parity, somatic cell count was lower in organic cows than conventional cows. There was a higher proportion of quarters that were dried off at the herd visit in organic herds. No differences in the interval to first AI, interval to last AI or calving interval was revealed between organic and conventional cows. There was no difference between conventional and organic cows in quarter samples positive for mastitis bacteria from the herd visit. Milk yield and parity were associated with the likelihood of at least one quarter positive for mastitis bacteria. There was few S. aureus isolates resistance to penicillin in both management systems. Penicillin resistance against Coagulase negative staphylococci isolated from subclinically infected quarters was 48.5% in conventional herds and 46.5% in organic herds.

Conclusion

There were no large differences between reproductive performance and udder health between conventional and organic farming for Norwegian Red cows.     

Polyerositis and Arthritis Due to Escherichia coli in Gnotobiotic Pigs

Forty gnotobiotic pigs from six litters were exposed orally to Escherichia coli 083:K·:NM at 69 to 148 hours of age, while 17 pigs from the same litters served as unexposed controls. Clinical signs of infection included fever, anorexia, diarrhea, lameness, and reluctance to move.

Eighty-four percent of the exposed pigs in four litters died, while only 13% in two litters died. Gross and microscopic lesions included serofibrinous to fibrinopurulent polyserositis in 96% of the exposed pigs in four litters and 33% of the exposed pigs in two litters. A few pigs had gross and/or microscopic lesions of arthritis. Escherichia coli was routinely isolated from the serous and synovial cavities of infected pigs.

Anti-hog cholera serum administered orally as a colostrum substitute gave partial protection against E. coli infection.

     

ACANTHOMATOUS AMELOBLASTOMA OF THE MAXILLA OF AN ADULT ALPACA

An adult alpaca presented with a large maxillary swelling. Facial trauma or a tooth root abscess was suspected. Radiographically there was a large expansile lesion displacing the right maxillary teeth. An ameloblastoma was diagnosed histologically and palliative radiation therapy was attempted. Because of poor response to therapy and anorexia the animal was euthanized. Necropsy findings confirmed an ameloblastoma of acanthomatous type.     

Processing of corn and sorghum for feedlot cattle.

Approximately 75% to 80% of expenses involved in cattle feeding in commercial feedlots are feed costs. Grains are used in feedlot diets to improve the performance and efficiency of feedlot cattle by increasing the energy density of diets. Grains for these diets are commonly processed for various reasons, including improving palatability, altering particle size, increasing digestibility, altering the rate, site, and extent of digestion, and facilitating preservation or storage. Altering the rate, site, and extent of digestion in turn can alter cattle performance. This article focuses on processing methods common to feedlots and the primary grains fed, corn and grain sorghum.     

Natural zooplankton as larval feed in intensive rearing systems for juvenile production of Atlantic cod (Gadus morhua L.)

The growth potential of cod larvae is not fully achieved when rotifers (Brachionus spp.) are used as live feed. In this experiment, we studied the effect of natural zooplankton (mainly copepods) on the growth of cod (Gadus morhua L.) larvae reared in intensive systems. Using a growth model developed for cod larvae, the growth rates observed could be evaluated and compared with growth rates reported previously. The cod larvae showed optimal growth rates until age 19 days post hatch (DPH) when they reached 9.77 ± 0.25 mm standard length (SL). Early weaning (20–25 DPH) resulted in significantly longer larvae at age 30 DPH compared with late weaning (25–32 DPH); however, in this period, the zooplankton concentrations were low. The experimental larvae showed considerably higher growth rates compared with rotifer (Brachionus spp.)‐reared cod larvae in previous experiments. The nutritional composition of cod larvae was analysed and compared with published results on rotifer‐reared larvae. The levels of iodine, manganese, selenium and n‐3 PUFA were considerably higher in larvae fed copepods compared with larvae fed rotifers. The differences in nutritional status may well explain the differences in growth observed between copepod and rotifer‐reared larvae.     

Effect of light intensity and feed density on feeding behaviour,growth and survival of larval sablefish Anoplopoma fimbria

We studied the effects of light intensity on larval activity, feeding behaviour, growth and survival of a candidate species for aquaculture – sablefish (Anoplopoma fimbria). Of six light intensities ranging from 2 to 750 lux at the water surface, the greatest surviving biomass in small tanks was observed at 12–42 lux. In another experiment in larger tanks, behavioural observations showed that larvae fed poorly under light brighter than 800 lux but fed better at lower light intensities, depending on tank type. In a separate experiment, where live feed densities were varied between 2.5 and 17.5 rotifers per mL of tank water, surviving biomass and dry weight increased with higher feed densities. These experiments help refine methods for rearing larval sablefish by demonstrating effects of light intensity and feed density on larval performance.     

Observations of comet 19P/Borrelly by the miniature integrated camera and spectrometer aboard Deep Space 1

The nucleus of the Jupiter-family comet 19P/Borrelly was closely observed by the Miniature Integrated Camera and Spectrometer aboard the Deep Space 1 spacecraft on 22 September 2001. The 8-kilometer-long body is highly variegated on a scale of 200 meters, exhibiting large albedo variations (0.01 to 0.03) and complex geologic relationships. Short-wavelength infrared spectra (1.3 to 2.6 micrometers) show a slope toward the red and a hot, dry surface (相似文献