Browsing by Author "Reddy, G.V.P."
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- ItemApproaches and mechanisms for ecologically based pest management across multiple scales(Elsevier B.V., 2016) Zhao, Z.H.; Reddy, G.V.P.; Hui, C.; Li, B.L.The past 50 years have seen substantial change of agroecosystems in the world, including an intensified use of agrochemicals and expansion of cropland, resulting in a rapid loss of biodiversity and a reduction of ecosystem services. The effects of these changes, at both the field and landscape scale, on ecologically based pest management (EBPM) in agroecosystems have become increasingly important. Here, we review the theories, important approaches and mechanisms of habitat management practices (at multiple spatial scales) that can be applied to facilitate EBPM in crop fields and even over larger landscapes. In particular, we discuss links between pest outbreaks and rapid changes of habitat composition at local and regional scales. We also summarize recent progress of habitat management and their application to pest management, which is an activity that we believe must be implemented at multiple spatial scales to successfully conserve ecosystem services and address environmental issues related to crop pest control.
- ItemA geometrical model for testing bilateral symmetry of bamboo leaf with a simplified Gielis equation(John Wiley & Sons Ltd, 2016) Lin, S.; Zhang, L.; Reddy, G.V.P.; Hui, C.; Gielis, J.; Ding, Y.; Shi, P.The size and shape of plant leaves change with growth, and an accurate description of leaf shape is crucial for describing plant morphogenesis and development. Bilateral symmetry, which has been widely observed but poorly examined, occurs in both dicot and monocot leaves, including all nominated bamboo species (approximately 1,300 species), of which at least 500 are found in China. Although there are apparent differences in leaf size among bamboo species due to genetic and environmental profiles, bamboo leaves have bilateral symmetry with parallel venation and appear similar across species. Here, we investigate whether the shape of bamboo leaves can be accurately described by a simplified Gielis equation, which consists of only two parameters (leaf length and shape) and produces a perfect bilateral shape. To test the applicability of this equation and the occurrence of bilateral symmetry, we first measured the leaf length of 42 bamboo species, examining >500 leaves per species. We then scanned 30 leaves per species that had approximately the same length as the median leaf length for that species. The leaf-shape data from scanned profiles were fitted to the simplified Gielis equation. Results confirmed that the equation fits the leaf-shape data extremely well, with the coefficients of determination being 0.995 on average. We further demonstrated the bilateral symmetry of bamboo leaves, with a clearly defined leaf-shape parameter of all 42 bamboo species investigated ranging from 0.02 to 0.1. This results in a simple and reliable tool for precise determination of bamboo species, with applications in forestry, ecology, and taxonomy.
- ItemPlant species richness controls arthropod food web: Evidence from an experimental model system(Oxford University Press on behalf of Entomological Society of America, 2019) Zhao, Z.-H.; Hui, C.; Reddy, G.V.P.; Ouyang, F.; Men, X.-Y.; Ge, F.The effects of plant species richness on the function and stability of ecosystems have been an area of focus in recent decades. Arthropod community is one of the most important components in agroecosystems and can provide multiple ecosystem services, including biocontrol and pollination. In particular, species composition and biocontrol function can be sensitive to changes in plant species richness. Here, we designed 50 plots with five levels of plant species richness to examine arthropod distribution and composition over 4 yr. Arthropod richness was found to be positively correlated with plant species richness. High plant species richness can enhance the temporal stability of the arthropod community but can also lead to a decline in the population stability of some species. The species richness and biomass of environmentally friendly insects (EFI), such as honeybees, ants and flies, were found to be positively correlated with those of the natural enemies. As such, high levels of EFI could sustain food web robustness by serving as alternative prey/hosts for natural enemies. The mediation of EFI in the interaction between crops and pests has implications for successful biocontrol practices using natural enemies. Planting diverse plant species with a certain level of spatial turnover could benefit the biocontrol function of natural enemies and safeguard multiple ecosystem services.