본 연구는 2008년부터 2016년까지 한강 지류 중랑천을 대상으로 수환경 변화에 따른 어류 군집 양상을 파악하고자 실시하였다. 조사결과, 중랑천에서 서식하는 어류는 총 9과 37종 8,421개체로 나타났으며 과별 출현 종수는 잉어과에서 23종 (62.2%)으로 가장 많은 종이 출현하였고, 생태계교란종 및 외래종은 모두 강우기 후 출현하는 특성을 보였다. 수질변화에 따르면, BOD, EC, TN, TP의 변화는 강우량의 증가에 따라 감소하는 양상을 보이는 반면, SS 변화는 증가하는 양상을 보였다. 지점간 CA결과 한강 본류와 인접한 St. 7과 St. 1, 3, 5가 어류의 출현양상 차이를 보였으며, PCA 분석결과 상류에서 하류, 강우기 전과 후의 어류 출현양상과 유기오염지표의 변화 양상을 보였다.
The yellow spotless ladybug (YSL), Illeis koebelei is a kind of aboriginal ladybug in Korea. YSL feed on the fungi and extraordinary prefer to powdery mildew (PM). This study was conducted to investigate the developmental characteristic and the biological control effect on the cucumber PM by the YSL from 2010 to 2012. YSL were detected on the 12 species of host plants infected with PM. and occurrence was observed from the early of July to the early of November in Gyeonggi area. The feeding amount of YSL on the cucumber PM was in order of 4th larva, adult, 3rd larva, 2nd larva and 1st larva. The optimum developmental temperature and photoperiod for YSL was 20∼25℃ and 16L:8D respectively. Three species of fungi were selected as the short term substitution feed for YSL. Control effect on cucumber PM under 2.5% of occurrence rate was linearly increased in proportion to increased numbers of 3rd larva were applied. Combination treatment of the fungal agent with YSL enhanced suppression of cucumber PM more than either agent used alone. The safety agricultural chemicals were selected harmless to the survival of larva and adult of YSL. The survival rate of pupae and adult was over 80% after storage at 10∼12℃ for 30 days. Five species of banker plant were selected for maintenance of YSL during growing season in greenhouse.
To understand the oviposition biology of arrowhead scale, Unaspis yanonensis (Kuwana) (Homoptera: Diaspididae), the longevity and fecundity of the overwintered females were examined at various temperatures (16, 20, 24, 28, and 32℃). The total fecundity increased with rising temperature, showed a maximum of 260.9 crawlers per female at 24℃, and then declined thereafter. Females showed a periodical oviposition activity. The 1st cycle fecundity was identified at all temperatures examined, and was not significantly different between 16 and 28℃. However, the 2nd cycle fecundity and later cycle fecundity were much lower at 16, 20, and 32℃ than those at 24 and 28℃. The pre-oviposition period ranged from 49.0 d at 16℃ to 19.7 d at 32℃, and was the shortest 19.4d at 28℃. The linear lines of mean development rates (1/mean pre-oviposition period) against temperatures provided the estimate of low-threshold temperature 8.7℃ for pre-oviposition stage and the thermal constant of 358.1 DD. The lower threshold temperature and thermal constant for the completion of U. yanonensis pre-oviposition period well predicted the first crawler occurrences in the fields.
본 연구에서는 지역특성(위도, 경도, 고도)과 기후학적 특성(연최대강우량)을 계층적 Bayesian 모형안에서 연계하여 공간적 분석이 가능한 지역빈도해석 모형을 개발하였다. 기존 지역빈도해석은 강수지점의 지리적/지형적 특성을 반영한 해석이 어려운 단점이 있으며, 지점을 기준으로 해석된 확률강수량을 유역면적강우량으로 변환 시 불확실성이 큰 단점이 있다. 이에 본 연구에서는 계층적 Bayesian 기법을 이용하여 지역특성 및 기후학적 특성이 고려된 Gumbel 확률분포형의 매개변수를 추정하였으며, 이들 매개변수들을 공간적으로 보간하여 한강유역내 모든 지점에 대해서 확률강수량을 추정할 수 있도록 하였다. 결과적으로 기존 L-모멘트 방법과 유사한 결과를 확인할 수 있었으며 확률강수량의 불확실성 정량화와 더불어 지리적/지형적 영향을 고려한 해석이 가능하였다.