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Ye Y.,South China Agricultural University | Ye Y.,Key Laboratory of Agro Environment in the Tropics | Zhang J.E.,South China Agricultural University | Zhang J.E.,Key Laboratory of Agro Environment in the Tropics | And 3 more authors.
Applied Ecology and Environmental Research | Year: 2015

This study analyzed the landscape pattern changes, the dynamics of the ecosystem service values (ESVs) and the spatial distribution of ESVs from 1995 to 2005 in Guangzhou, which is the capital of Guangdong Province and a regional central city in South China. Remote sensing data and geographic information system techniques, in conjunction with spatial metrics, were used to facilitate the analysis. The forest was the main landscape with a total coverage of 37.36% during the study period. Between 1995 and 2005, the forest and garden became less fragmented while the cultivated land, grassland, water body and built-up area became more fragmented. Such landscape pattern changes have resulted in a significant increase in the overall annual ESVs in Guangzhou of approximately 3.37%. Two important landscape types (forest and water body) were the main contributor to the total ESVs, the proportion of both of which was over 75%. During the period from 1995 to 2005, the ESVs tended to decline from the north and south to the central part in Guangzhou. The average ESVs was more than 15 000 Yuan/ha in the north for the mountainous forest area and 20 000 Yuan/ha in the south for the water body at the Pearl River mouth, but the average ESVs was lower than 5 000 Yuan/ha in the central part of the study area due to low vegetation coverage and widely scattered built-up area for rapid urbanization. So, it is important to protect the key landscape types, such as forest, water body and garden, to avoid fragmentation. Furthermore, this study offers important insights to those in fast-urbanizing regions for achieving more successful landscape to obtain the increasing of ESVs. © 2015, ALÖKI Kft., Budapest, Hungary. Source


Zhao B.,South China Agricultural University | Zhao B.,Key Laboratory of Agro Environment in the Tropics | Zhang J.,South China Agricultural University | Zhang J.,Key Laboratory of Agro Environment in the Tropics | And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2014

Pomacea canaliculata (Lamarck) is an invasive aquatic gastropod endangering rice production in Southern China, with a feeding preference for rice seedlings in paddy fields. P. canaliculata is listed as one of the top 100 invasive species by the Invasive Species Group of the World Conservation Union. P. canaliculata mainly feeds on a diverse range of macrophyte species. We investigated the invasive effects of P. canaliculata on the aquatic macrophyte plant community in paddy fields. Our experimental macrophyte community consisted of Oryza sativa L., Pistia stratiotes L., Eichhornia crassipes, Myriophyllum aquaticum, Alternanthera philoxeroides, Monochoria vaginalis. The control and three treatments used different P. canaliculata densities: control (P. canaliculata-free); low (4 individuals/ m2); medium (8 individuals/m2) and high (12 individuals/ m2). We analyzed the effect that P. canaliculata had on the macrophyte community using the compound food preference test. Our results showed: 1) O. sativa densities in the three treatments decreased rapidly one week after P. canaliculata was introduced. In herbivore, in the P. canaliculata high-density treatment, O. sativa density declined approximately 70%. However, two weeks after P. canaliculata was introduced, the herbivore effect on O. sativa density decreased. 2) After eight weeks P. canaliculata reduced A. philoxeroides and M. vaginalis densities (30% and 25%, respectively) in the high-density herbivore treatment and inhibited the growth of A. philoxeroides and M. vaginalis. The plant densities of A. philoxeroides and M. vaginalis were higher in the low-density herbivore treatment compared with those in the medium and high-density herbivore treatments. However, P. canaliculata showed no significant effect on the plant densities of E. crassipes, P. stratiotes and M. aquaticum. 3) The daily density rate of increase was negative for O. sativa, and significantly different in the low, medium and high-density herbivore treatments. The daily density rate of increase for O. sativa showed a significant decrease compared with the P. canaliculata-free control. The daily density rate of increase for A. philoxeroides and M. vaginalis was positive, where the rate was significantly lower compared with the P. canaliculata-free control. Concurrently, the daily density rates of increase were not significantly influenced by P. canaliculata for P. stratiotes, E. crassipes and M. aquaticum. We found that P. canaliculata populations increased rapidly. The daily density rate of increase for P. canaliculata populations in the three different density treatments were all high, but not significantly different. The food preference frequencies of P. canaliculata on O. sativa, A. philoxeroides and M. vaginalis were all significantly higher compared with E. crassipes, P. stratiotes and M. aquaticum. 4) Eight weeks after the introduction of P. canaliculata the Simpson, Shannon and Homogeneity biodiversity indices showed a significant decline in the aquatic macrophyte community. The Simpson index values showed the decline in order of: the control > low-> medium-and high-densities. The Shannon and Homogeneity indices showed the decline in order of: the control > low-> medium-> high-densities. We conclude that P. canaliculata showed significantly different feeding preference on macrophyte plants species. The invasion of P. canaliculata would significantly endanger aquatic macrophyte community biodiversity in the paddy fields of China. Source


Liang K.-M.,South China Agricultural University | Liang K.-M.,Key Laboratory of Agro Environment in the Tropics | Zhang J.-E.,South China Agricultural University | Zhang J.-E.,Key Laboratory of Agro Environment in the Tropics | And 7 more authors.
Chinese Journal of Ecology | Year: 2013

A laboratory experiment was conducted to study the effects of mechanical stimulation on the physiological characters of rice plant. Mechanical stimulation decreased the permeability of rice leaf plasma membrane, but, with the increase of stimulation intensity and treatment time, the permeability presented an increasing trend. The leaf chlorophyll a (Chl-a) content was increased by mechanical stimulation treatments, while the leaf chlorophyll b (Chl-b) content presented a decreasing trend. Low intensity mechanical stimulation increased the activities of protective enzymes peroxidase (POD), superoxide dismutase (SOD), and polyphenol oxidase (PPO) in rice leaves. In mechanical stimulation treatments, the leaf 3-indoleacetic acid (IAA) content was reduced with time, whereas the leaf abscisic acid (ABA) content and the root activity showed an opposite trend. These results indicated that mechanical stimulation could be one of the important reasons leading to the morphological and physiological variations of rice plant. The findings from this study could provide a theoretical basis to further study the effects and action mechanisms of mechanical stimulation on the rice plant growth in rice-duck farming system. Source


Ye Y.-Q.,Key Laboratory of Agro Environment in the Tropics | Ye Y.-Q.,Guangdong Engineering Research Center for Modern Eco agriculture and Circular Agriculture | Ye Y.-Q.,South China Agricultural University | Zhang J.-E.,Key Laboratory of Agro Environment in the Tropics | And 6 more authors.
Chinese Journal of Applied Ecology | Year: 2016

From the land use vector data of Guangzhou-Foshan Metropolitan Area (GFMA) in 1990, 1995, 2000, 2005 and 2010, four types of agriculture and forestry ecosystem (cropland, forestland, garden and water body) were extracted. Then, we evaluated the GFMA's agriculture and forestry ecosystem services value (AESV) based on Costanza's method after adjusting the 'ecosystem services value per unit area of China's terrestrial ecosystem' raised by Xie Gaodi through regional, functional and economic factor adjustment. The results showed that the total AESV had a wavelike upward trend due to the continuous development of economy and the increase of people's living standards in GFMA. The AESV in GFMA was 413.74×108, 612.83×108, 582.88×108, 773.44×108 and 698.67×108 yuan in 1990, 1995, 2000, 2005 and 2010, respectively. During the studied period, water body's service value grew fastest, which was 166.74×108 yuan, and followed by forestland and garden amounting to 103.01×108 and 47.74×108 yuan, respectively, while the cropland's service value decreased by 32.56×108 yuan and the decreasing rate was 23.1%. According to the spatial distribution, the AESV tended to decline from the northeast and the southwest to the central part in GFMA from 1990 to 2010. The proportion of individual service value to the total services value changed little, and the contribution of individual service value decreased in the order of water supply, waste treatment, biodiversity protection, climate regulation, soil formation and protection, gas regulation, recreation and culture, raw material and food production. © 2016, Science Press. All right reserved. Source


Guo J.,South China Agricultural University | Zhang J.-E.,South China Agricultural University | Zhang J.-E.,Key Laboratory of Agro Environment in the Tropics | Zhao B.,South China Agricultural University | And 4 more authors.
Biocontrol Science and Technology | Year: 2016

The golden apple snail Pomacea canaliculata is invasive in South China and poses serious harm to agricultural production and aquatic ecosystems. In the present study, we investigated the predatory potential of the spotted green pufferfish Tetraodon nigroviridis (50 mm in body length) on snails of various sizes in fresh and brackish water (4.5 ppt salinity). The survival and damage rates of 50 snails were estimated at 1, 3, 5 and 7 days. The survival rate of snails, including 10 adult snails (20–35 mm shell height), decreased less than 25% in the presence of pufferfish, and this decrease was more profound in brackish than in fresh water. Approximately 98% of the snails died in brackish water in the presence of only four pufferfish. The pufferfish also inflicted a high rate of snail injury resulting from attacks involving bites. In addition, the pufferfish affected the behaviour of the snails, with more than 95% of snails exhibiting tightly closed opercula. Thus, the results of this study suggest that pufferfish are effective for the biological control of golden apple snails. © 2016 Informa UK Limited, trading as Taylor & Francis Group. Source

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