Research For Grazing Behavior Based On Grazing Spatio-temporal Trajectory Data

In China,more than 61.49% of the grassland has been degraded,overgrazing is one of the main reasons of grassland degradation.Serious degradation of grassland resources has become a major obstacle to the economic development of animal husbandry.Monitoring and analysis of grazing behavior is helpful to the determination of scientific grazing strategy and the making of grassland construction,as well as contributing to the sustainable and balanced development of grassland economy and ecology.However,existing grazing behavior monitoring method which was calculated by the number of tack points per unit area,the temporal and spatial distribution of feed intake cannot be quantified directly.At present,the response of flock movement speed to vegetation and topography has not been considered in the study of sheep grazing behavior and interaction with grassland environment.Besides,there are more domestic and foreign scholars for herd monitoring system design and development,However,this study generally only achieved display of realtime position,playback of history track and electronic fence alarm functions,the existing system cannot meet the greater requirement for monitoring of feed intake distribution and grazing intensities.In order to solve the above problems,the systemic grazing behavior studies were carried out in this thesis.With the rapid development of Global Navigation Satellite System,the grazing trajectory data of heads can be collected conveniently.Grazing trajectory records the information of feeding process such as time,position and velocity.In this paper,a temporal and spatial distribution model of feed intake based on trajectory data of grazing is proposed.The spatial distribution features of feed intake and the characteristics of flock movement speed are extracted,while the impacts of vegetation biomass,season,slope angle and aspects on grazing behavior are analyzed.The main research work of this paper was illustrated as follows:(1)To obtain the distribution of feed intake quantitatively,using spatial analysis methods such as buffer analysis,grid analysis and overlay analysis,a temporal and spatial distribution model of feed intake based on trajectory data of grazing is proposed.The model is subsequently utilized to compute the feed intake distribution.We collected grazing trajectory data of sheep in the studied grassland from July to October in 2015.Taking these grazing trajectory data as input,the model gives the corresponding feed intake distribution.The model result reveals that: a)feed intake is relatively higher in those place where trajectory points are intensive;b)feed intake distribution varies with the different periods which is highly consistent with rotational grazing cycle;c)There is a significant negative correlation between feed intake and slope of terrain,and the correlation coefficient was-0.612.To verify the accuracy of the proposed model,we analyzed the correlation between the feed intake and forage surplus of each sample area,and the result shows the modeled feed intake is significantly negatively correlated with forage surplus,with a correlation coefficient of-0.704,and the accuracy of the model is 86.2%.(2)In order to analyze the impacts of vegetation biomass,season,slope angle and aspects on grazing behavior,using Beidou/GPS to record the time,position and speed of grazing,and employing remote sensing to obtain the quantitative and spatial distribution of vegetation of the pasture,then adopted manifold methods,such as spatial analysis,multivariate statistical analysis and variable control.It was found that the average flock movement speed was different among different periods in one day,during the beginning and finishing times of grazing the speed was relatively high,while during middle period of grazing times it was relatively low.Within one year,there was a significant negative correlation between flock movement speed and vegetation biomass,and the correlation coefficient was-0.778.For the shady slop,flock movement speed,with the biomass increases,showed a gradual decrease trend,and with slope angle increases,also showed a gradual decrease trend.But the speed has no obvious regularity for the sunny slope.The flock movement speed of shady slope was less than sunny slope in addition.(3)In order to monitor the grazing behavior information,such as feed intake distribution,grazing intensities and trajectories.Based on the established internet of things location service platform,a monitoring system for grazing behavior was designed by integrating with the spatial analysis and visualized analysis technology of WebGIS.The system has been put into application in monitoring of grazing behavior in study area,the results showed that the system could efficiently and dynamically monitor the position,feed intake distribution and grazing intensities information,and this system can provide technical support and data support for the monitoring of grazing information.