Previous research has explored the potential to integrate lidar and optical data in aboveground biomass(AGB)estimation,but how different data sources,vegetation types,and modeling algorithms influence AGB estimation i...Previous research has explored the potential to integrate lidar and optical data in aboveground biomass(AGB)estimation,but how different data sources,vegetation types,and modeling algorithms influence AGB estimation is poorly understood.This research conducts a comparative analysis of different data sources and modeling approaches in improving AGB estimation.RapidEye-based spectral responses and textures,lidar-derived metrics,and their combination were used to develop AGB estimation models.The results indicated that(1)overall,RapidEye data are not suitable for AGB estimation,but when AGB falls within 50–150 Mg/ha,support vector regression based on stratification of vegetation types provided good AGB estimation;(2)Lidar data provided stable and better estimations than RapidEye data;and stratification of vegetation types cannot improve estimation;(3)The combination of lidar and RapidEye data cannot provide better performance than lidar data alone;(4)AGB ranges affect the selection of the best AGB models,and a combination of different estimation results from the best model for each AGB range can improve AGB estimation;(5)This research implies that an optimal procedure for AGB estimation for a specific study exists,depending on the careful selection of data sources,modeling algorithms,forest types,and AGB ranges.展开更多
The functional response of adult Nabis kinbergii （Hemiptera： Nabidae） to density of diamondback moth Plutella xylostella （Lepidoptera： Plutellidae） was investigated under laboratory conditions. Holling＇ s （195...The functional response of adult Nabis kinbergii （Hemiptera： Nabidae） to density of diamondback moth Plutella xylostella （Lepidoptera： Plutellidae） was investigated under laboratory conditions. Holling＇ s （1959） type Ⅱ model was found to be a good fit for the observed functional response of this predator. The numbers of P. xylostella consumed increased with temperature from 15℃ to 35℃. The maximum number of prey killed was observed at 35℃, with average of 10.3 and 8.3 forth instar larvae consumed by adult females and males of N. kinbergii, respectively. The predation of N. kinbergii on P. xylostella increased with successive immature stages. The number of prey consumed by predators decreased as the body size of prey increased. An average of 131 eggs or 95 larvae of P. xylostella were killed by a single of female adult in 24 hours at 24＂C. The pupae of P. xylostella were observed to be eaten by fifth instar nymphs and adults N. kinbergiiin numbers of less than an average of 0.7 pupae per predator in 24 hours at 24＂C. Predation preference by N. kinbergii was also investigated. The number of P. xylostella and Myzus persicae killed by female N. kinbergii was not significantly different, but males killed significantly more P. xylostella than M. persicae. Both eggs and larvae of P. xylosteUa were killed in significantly greater number than those of Pieris rapae in the same feeding arena.展开更多
People are donning extra layers to buttress themselves against sharpening winds. They move a bit faster, conducted by walking cadences by slowly dropping temperatures.
基金supported by the National Natural Science Foundation of China(No#41571411)the Zhejiang A&F University’s Research and Development Fund for the talent startup project(No#2013FR052)+1 种基金Keller,dos-Santos,Bolfe,and Batistella acknowledge the support from the Brazilian National Council for Scientific and Tech-nological Development–CNPq(No#457927/2013-5)Data were acquired by the Sustainable Landscapes Brazil project supported by the Brazilian Agricultural Research Corporation(EMBRAPA),the US Forest Service,the USAID,and the US Department of State.
文摘Previous research has explored the potential to integrate lidar and optical data in aboveground biomass(AGB)estimation,but how different data sources,vegetation types,and modeling algorithms influence AGB estimation is poorly understood.This research conducts a comparative analysis of different data sources and modeling approaches in improving AGB estimation.RapidEye-based spectral responses and textures,lidar-derived metrics,and their combination were used to develop AGB estimation models.The results indicated that(1)overall,RapidEye data are not suitable for AGB estimation,but when AGB falls within 50–150 Mg/ha,support vector regression based on stratification of vegetation types provided good AGB estimation;(2)Lidar data provided stable and better estimations than RapidEye data;and stratification of vegetation types cannot improve estimation;(3)The combination of lidar and RapidEye data cannot provide better performance than lidar data alone;(4)AGB ranges affect the selection of the best AGB models,and a combination of different estimation results from the best model for each AGB range can improve AGB estimation;(5)This research implies that an optimal procedure for AGB estimation for a specific study exists,depending on the careful selection of data sources,modeling algorithms,forest types,and AGB ranges.
文摘The functional response of adult Nabis kinbergii （Hemiptera： Nabidae） to density of diamondback moth Plutella xylostella （Lepidoptera： Plutellidae） was investigated under laboratory conditions. Holling＇ s （1959） type Ⅱ model was found to be a good fit for the observed functional response of this predator. The numbers of P. xylostella consumed increased with temperature from 15℃ to 35℃. The maximum number of prey killed was observed at 35℃, with average of 10.3 and 8.3 forth instar larvae consumed by adult females and males of N. kinbergii, respectively. The predation of N. kinbergii on P. xylostella increased with successive immature stages. The number of prey consumed by predators decreased as the body size of prey increased. An average of 131 eggs or 95 larvae of P. xylostella were killed by a single of female adult in 24 hours at 24＂C. The pupae of P. xylostella were observed to be eaten by fifth instar nymphs and adults N. kinbergiiin numbers of less than an average of 0.7 pupae per predator in 24 hours at 24＂C. Predation preference by N. kinbergii was also investigated. The number of P. xylostella and Myzus persicae killed by female N. kinbergii was not significantly different, but males killed significantly more P. xylostella than M. persicae. Both eggs and larvae of P. xylosteUa were killed in significantly greater number than those of Pieris rapae in the same feeding arena.
文摘People are donning extra layers to buttress themselves against sharpening winds. They move a bit faster, conducted by walking cadences by slowly dropping temperatures.
