Development of biotic modules for integration into the cropping system model
Process-based crop models are widely used as strategic decision support tool to assess the interactive effects of climate, crop, soil and management on crop productivity. The impacts of various abiotic components on crop productivity are already incorporated in sufficient detail in most of the widely used crop models. However, the impact dues to biotic constraints (pests, diseases and weeds) on productivity have only recently begun to be incorporated into these process models. As part of the USDA NIFA-funded project 'Regional Approaches to Climate Change for Pacific Northwest Agriculture' (REACCH), the long-term viability of cereal-based farming in the Pacific Northwest (PNW) is assessed with cropping system models. The impact of biotic constraints on the productivity of wheat under baseline and future climate change for PNW region is a major focus of this project. In particular, the current work is focused on the development of a biotic module and its integration into the cropping system model, CropSyst, to assess the impact of climate change on the rates of development and herbivory of cereal leaf beetle (CLB), Oulema melanopus (L.) (Coleoptera: Chrysomelidae), on winter wheat, Triticum aestivum. Invaded from Europe, CLB is becoming a serious pest of small grains in the Unites States into the 21st century. United States Department of Agriculture (USDA) has cited CLB as one of the potential pest to cause increased crop damage with warming temperatures. The life cycle of most insect pests are driven largely by direct effects of temperature and there is little evidence of any direct effects of CO2. Elevated temperature will cause faster developmental rates in insects by increasing their metabolism rates in a nonlinear fashion, increase the winter survival rate of different life stages of pest, disrupt their synchrony of emergence with natural enemies and increase risk of damage to crops. Development of a nonlinear temperature-dependent population model is expected to help predict population growth potential of CLB and link the relative abundance of CLB to the feeding damage potential to wheat under future climate scenarios in the various agro-climatic zones of PNW. The outcomes from the project are expected to help plan adaptation strategies for integrated pest management in a changing climate and inform policies on global food security.,
Byju's interests in ecology encompass impacts of natural and anthropogenically induced changes in climate and landscapes on the population dynamics and trophic relationships of organisms and its implications for global biodiversity and food security. Using insects as model fauna, he employs observational, empirical and modeling approach to appreciate the effect of anthropogenic changes in climate and land use, in isolation and interaction, for population and community dynamics, and trophic interactions including herbivory and biological control. He seeks to improve strategies for species conservation, and develop decision support tools to manage agricultural pests for improved crop productivity. Currently, Byju is postdoctoral research assistant in the Biotic team of USDA NIFA-funded project 'Regional Approaches to Climate Change for Pacific Northwest Agriculture' (REACCH). Working as postdoctoral research assistant under the guidance of Claudio Stockle (WSU) and Sanford Eigenbrode (UI), he is into development of a process based simulation model to assess the impact of climate change on the cereal leaf beetle (Oulema melanopus) phenology and population dynamics, and damage potential to wheat, Triticum aestivum. Land use change due to agricultural expansion and urbanization has reconfigured many plant populations, their herbivores, natural enemies and pollinators into metapopulations, i.e., local populations linked by dispersal. The metapopulation concept and its community-level extensions has become a popular theoretical framework to appreciate species dynamics and community structure in fragmented landscapes. However, empirical tests have lagged behind theory. For his PhD, Byju conducted lab and field studies to test the predictions on metapopulation theory. In the field, he studied the impact of forest fragmentation on acorn weevil (Curculio spp .) population dynamics in relation to natural regeneration of oak forests using hierarchical patch occupancy models. He also investigated the spatio-temporal effects of connectivity between patches and resource fragmentation on the dispersal and persistence of species using red flour beetle [Tribolium castaneum(Herbst)]. These latter experiments were carried out in static versus dynamic micro-landscapes to assess the role of patch restoration rate and matrix heterogeneity on metapopulation dynamics.
Publications and Presentations:
Govindan, B., Davis, T., Eigenbrode, S., Stockle, C. 2015. Coupling Insect Pest Phenology Model into CropSyst: Cereal Leaf Beetle and Wheat Yield. Washington State University (poster).
Govindan, B., Eigenbrode, S., Stockle, C. Interactive Effects of CO2 and Warming on Cereal Leaf Beetle Dynamics and Winter Wheat Yield in the Pacific Northwest USA. Transitioning Cereal Systems to Adapt to Climate Change Meeting, Nov. 13-14, 2015, Minneapolis, MN (poster).