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Zhu L.-Q.,Zhejiang GongShang University | Zhang Z.,Research Institute of Forest Ecology
Pan-Pacific Entomologist | Year: 2013

This paper proposes a Lepidoptera insect image recognition method based on extracting image features using superpixels segmentation, encoding the features with Locality-constrained Linear Coding (LLC), aggregating codes with max pooling, and then classifying them with classification and regression tree (CART). This method used the natural scale color patterns on the insect wings as the basis for recognition, which can avoid the complicated chemical processing needed for venation based recognition. The method is tested in a dataset including 579 image samples from ten species of Lepidoptera species, and the recognition error rate is below 5%. The method also exhibits good performance with respect to time cost. The experimental results suggest that on the task of recognizing Lepidoptera species, the proposed method has state-of-the-art performance with high efficiency. © Pacific Coast Entomological Society.

Wang B.,Research Institute of Forest Ecology
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University | Year: 2015

Evaluating the ecological status of forests and understanding the accomplishment so far of establishing our study of the ecology on a firm footing at the national level, demands a complete system for continuous observations and inventory records. The technology of continuous observations and an inventory of a complete index system of forest ecosystem services (referred to as TCOICISFES) includes two subsystems: continuous investigation of field observations (CIFO) and distributed measurement evaluation (DME). In CIFO, the principles of the layout of the system of observations have been established. China has constructed the largest nationwide network of forest ecological stations in the world and systematically assembled facilities and equipment. Hence, the CIFO indices can be described and are measurable at national forestry standards. Simultaneously, these standards were utilized to conform to data acquisition and transmission in the CIFO system. In the process of building the DME system, a distributed measurement method was created, an index system of evaluation was examined and established and data of national forest resources and related statistics were integrated and coupled. As well, we propose a system of correction coefficients for forest ecological functions and integrated with a series of evaluation formulas and a package of models. The TCOICISFES can be used along with the national forest resource inventory to function as one of the key technologies for observing and evaluating forest ecological conditions. This includes an inventory of national forest ecosystem services, estimates of ecological benefits derived from returning farmland to forests and a green national economic accounting system. ©, 2015, Beijing Forestry University. All right reserved.

Liu J.,Chinese Academy of Forestry | Liu J.,Key Laboratory of Tree Breeding and Cultivation | Yang W.,Chinese Academy of Forestry | Jiang Z.,Chinese Academy of Forestry | And 3 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2011

Thuja sutchuenensis Franch. is a critically endangered plant that is endemic to China. Currently, no research has addressed its endangered status from the perspective of its photosynthetic mechanism. Light is one of the most important environmental factors that can affect plant survival and growth and could become a major limiting factor for natural regeneration. Therefore, we focused on the adaptive ability of T. sutchuenensis seedlings under three light levels (L0 = full light; L1 = 50% full light; L2 = 25% full light) by comparing their photosynthetic capacity, chlorophyll fluorescence parameters, and chlorophyll content. We found that shading resulted in increases in the apparent quantum efficiency (α) and maximum leaf net photosynthetic rate (P max). At lower light levels, the dark respiration rate (R d), light compensation point (LCP), and light saturation point (LSP) declined. For the chlorophyll fluorescence parameters, PS II primary energy conversion efficiency (Fv / Fm), PS II potential activity (Fv / Fo), and photochemical efficiency of PS II in the light (Fv'/ Fm') were significantly higher at lower light levels than at L0, with parameters at L2 higher than at L1. Non- photochemical quenching (NPQ) also had a higher value under shade than under full light, and peaked at L1. With a decrease in light intensity, photochemical quenching (PQ) and the electron transport rate (ETR) decreased. Shading also caused a significant increase in leaf chlorophyll content (Chla + Chlb) per cm 2. These results indicate that T. sutchuenensis can tolerate a wide range light conditions, especially low light, and has internal regulatory mechanisms for responding to light level. Therefore, low light under canopy cannot be the decisive limiting factor for natural regeneration of T. sutchuenensis populations.

Wang X.-Y.,Research Institute of Forest Ecology | Yang Z.-Q.,Research Institute of Forest Ecology | Gould J.R.,Animal and Plant Health Inspection Service | Wu H.,Forestry Bureau of Sanming City in Fujian Province | Ma J.-H.,Forest Pest Control Station of Qinghai Province
Biological Control | Year: 2010

Spathius agrili Yang (Hymenoptera: Braconidae) is a newly described and important idiobiont ectoparasitoid of the emerald ash borer (EAB) that has excellent potential as a biological control agent against EAB populations in the USA. In order to understand the ecological factors involved in the search and discovery of concealed hosts by S. agrili, we investigated the behavioral responses of adult female wasps to potential semiochemicals from host plants, hosts, and host frass as well as to vibration signals from host feeding and movement. Using a bioassay, we showed that S. agrili first finds the host's habitats by detecting the volatile compounds emitted by ash. In the second phase of host location and acceptance, the parasitoids detect the mechanical vibrations produced by host feeding and movement under the surface of the bark and then probe to find the EAB larvae. Contact chemicals seem to play little or no role in short-range host finding. Female wasps avoided laying eggs on EAB larvae already parasitized and thus paralyzed. We hypothesized that female wasps were not attracted to these larvae due to their lack of feeding or movement. While an induced paralysis in the host is instrumental in avoiding superparasitism, we cannot rule out that S. agrili females also use an oviposition pheromone to deter conspecific females. Together, these results suggest that vibration and olfactory cues play significant roles in distinct phases of S. agrili host habitat and host location behaviors. © 2009 Elsevier Inc.

Tian Y.,Sun Yat Sen University | Tian Y.,Research Institute of Forest Ecology | Huang Z.,Research Institute of Forest Ecology | Xiao W.,Research Institute of Forest Ecology
Journal of Environmental Sciences | Year: 2010

Non-point source water pollution generated by agricultural production is considered a major environmental issue in the Three Gorges Reservoir Area (TGRA) of China. The Annualised Agricultural Non-Point Source Pollution (AnnAGNPS) model was selected to assess the impact of the application of various management treats, including seven crops, five fertilizer levels and three-group management practice scenarios, on water quality from Heigou River Watershed in TGRA. The scenario subsets include conservation tillage practice (CTP), conservation reserve program (CRP) and conversion of cropland into forestland program (CCFP). Results indicated that tea can not be replaced by other crops because comparatively tea resulted in a higher sediment yield. CTP with no-tillage was more effective to reduce sediment yield, but could increased nutrient loss. CRP reduced sediment yield significantly, but slightly benefited on nutrient loss. CCFP reduced not only sediment yield but also the nutrient loss significantly. The conversion of cropland with a slope greater than 10° into forestland was found to be the best scenario as the sediment yield export is less than 5 tons/ha and nutrient loss is within the permissible limit. © 2010 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

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