Study On Spatial Distribution Pattern Of Typical Shrub Plants In Steppe Desert Region Of Inner Mongolia

Reaumuria soongarica and Salsola passerine are extremely widely distributed shrubs in the central and western regions of Inner Mongolia,and they play a very important role in regional ecological protection and wind and sand control.However,their distribution areas have been affected by natural and human activities for a long time,resulting in the reduction of their distribution areas and population numbers,and producing a fault line in renewal,which greatly affects the stability of the ecosystem in this region.Therefore,the spatial distribution pattern of desert scrub and its spatial correlation were investigated by point pattern analysis based on the complete spatial randomness zero model and heterogeneous poisson zero model with UAV images in the steppe desert area,which theoretically explained the spatial distribution of desert shrubs under the lack of natural resources(soil water and nutrients)and the intra-and interspecific competition and symbiosis at different scales were theoretically explained.The redundancy analysis(RDA)method was applied to establish the correspondence between plant communities and various environmental factors,to explore the structural characteristics of plant communities and their species diversity under different precipitation levels,to reveal the mechanism of community structure formation,and to screen the dominant environmental factors that determine the spatial distribution pattern of plant species,which can help to formulate more effective conservation measures for desert shrub diversity.The results showed that:(1)the spatial distribution patterns of R.soongarica and S.passerina populations were uniform-random-aggregate under the complete spatial random-zero model,and the intensity and range of the aggregation distribution showed that the intensity and range of the aggregation decreased gradually with the decrease of the multi-year average precipitation,and the ecological relationships within the populations gradually weakened.The spatial correlations between R.soongarica populations and S.passerina populations decreased with precipitation,from negative correlation-no correlation-positive correlation to negative correlation at small scale and no significant correlation at large scale,and the interspecific relationships changed from competition to promotion,and the interspecific relationships gradually weakened at a larger scale without causing substantial influence on each other.(2)After exclusion of habitat heterogeneity,the R.soongarica population and S.passerina population were randomly distributed at >30 m scale,and the populations were independent of each other.The spatial correlations between R.soongarica and S.passerina populations were negative at 0-50 m scale,and the interspecific relationships were competitive,indicating that habitat heterogeneity was the main factor affecting the spatial distribution of populations at large scales.(3)Therefore,redundancy analysis was used to investigate the effects of environmental factors on plant populations,and it was found that the dominant environmental factors in the habitat that determined the spatial distribution patterns of plant species in the R.soongarica+ S.passerina community were soil p H,climatic factors,and elevation.(4)The populations of R.soongarica and S.passerine show a tendency of aggregated distribution in the natural state,and the restoration planting of these two plants can be considered to make the plants aggregated distribution instead of the traditional uniform planting or planting in rows.Therefore,the actual climatic conditions and the suitability of the soil environment should be considered in the revegetation of the area,and the high vegetation cover should not be pursued unilaterally.