AbstarctThis study was carried out to investigate the effect of different herb resource powders on meat quality and sensory properties in Korean native black goat for 500 d. The experimental treatment was arranged with 24 heads (3 treatment/8 heads) by control group, T1 and T2 group respectively (Control, not added herb powders; T1, 1% added herb powders; T2, 2% added herb powders). Total weight gain for the Korean native black goat was the highest in T2 group feeding for 500 days, and daily gain tended to be similar to the total weight gain. The total feed intake were the highest as 519.20 kg in T2 group, although feed conversion showed 18.35 in the T2 group, which means it had the best feed efficiency compared to the other treatment groups. The carcass rate was higher in the T1 group (51.10%) than in the other groups (p<0.05). The cooking loss and drip loss of Korean native black goat was the highest as 34.72% and 3.83% in the control group (p<0.05). However, total cholesterol amounts in the treatment group were not significantly different from, although tended to be higher than, the control group (p>0.05). Also, the overall sensory evaluation of the treatment group revealed low scores, meaning more meat flavor than those of the control in tenderness, flavor, texture, and black goat off-flavor and overall evaluation (p<0.05). Total synthesis evaluation was higher for the treatment group (3.71, 3.90 point) than that of the control group (4.82 point) (p<0.05). The MUFA/SFA ratio of the treatment group was not significantly different from, although tended to be higher than, the control group
Changes of geomorphology in alluvial river and vegetation recruitment on its floodplain downstream from dams are investigated both qualitatively and quantitatively focusing on the downstream of Andong dam and Imha dam on the Nakdong River. Results of the analyses of river morphology and bed material in the study site show a general trend of riverbed degradation with a max scour of 3 m and bed material coarsening from pre-dam value of 1.5 mm in D50 to post-dam value of 2.5 mm. Decrease in bed shear stress due to the decrease in flood discharge have caused vegetation recruitment on the once-naked sandbars. As result, the ratio of area of vegetated bars over total area of bars has drastically changed from only 7% in 1971 before the Andong dam (constructed in 1976) to 25% after it, and increased to 43% only three year after the Imha dam (constructed in 1992) and eventually to 74% by 2005. Analysis of the vegetation succession at Wicjeol subreach, one of the three subreaches selected in this study for detailed investigation, has clearly shown a succession of vegetation on once-naked sand bars to a pioneering stage, reed and grass stage, willow shrub and eventually to willow tree stages. At the second subreach selected, two large point bars in front of Hahoe Village seem to have maintained their sand surfaces without a signifiant vegetation recruitment until 2005. The sand bars, however, seem to have been invaded by vegetation recently, which warns river managers to have a countermeasure to protect the sand bars from vegetation invasion in order to conserve them for the historical village of Hahoe. On the other hand, recruitment and establishment of vegetation on the sand bars by artificial disturbance of the river, such as damming, can create an unique habitat of backmarsh in the sandy river, as shown in the case of Gudam Wetland, and may increase the biodiversity as compared with relatively monotonous sand bars. Last, the premise in this study that decrease in flood discharge due to upstream dams and decrease in bed shear stress can induce vegetation recruitment on the naked sand bars in the river has been verified with the analyses of the distribution of dimensionless bed shear stress along the selected cross section in each subreach.
ABSTRACT:The species distribution model would be a useful tool for understanding how invasive alien species spread over the country and what environmental variables contribute to their distributions. This study is focused on the potential distribution of two invasive alien species, the common ragweed (Ambrosia artemisiifolia) and knotgrass (Paspalum distichum) in the Korean Peninsula. The maximum entropy (Maxent) model was used for the prediction of their distribution by inferring their climatic environmental requirements from localities where they are currently known to occur. We obtained their presence data from the Global Biodiversity Information Facility and the Korean plant species databases and bioclimatic data from the WorldClim dataset. As a results of the modelling, the potential distribution predicted by global occurrence data was more accurate than that by native occurrence data. The variables determining the common ragweed distribution were precipitation of the driest month and annual mean temperature. Both annual and the coldest quarter mean temperatures were critical factors in determining the knotgrass distribution. The Maxent model could be a useful tool for the prediction of alien species invasion and the management of their expansion.
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