The Coexistence Mechanism Of Main Rodent In Desert Basing On The Multidimensional Niche

Revealing the mechanism of community species coexistence under heterogeneous environmental conditions has become a front edge and hot issue of ecological research in the world today.The Alxa desert is a typical temperate desert in Asia,which is significantly different from other continental deserts in terms of rodent nutrition and functional group relationships,community patterns,and human disturbance.However,the mechanism of rodent species coexistence in the desert of China is still unclear.From 2017 to 2021,the methods of marker recapture,infrared camera trap technology and stable isotope analysis were used to study the resource utilization patterns and niche division of rodents in the three dimensions of spatial,trophic,and temporal niches in Alxa desert area,aiming to put forward scientific hypotheses and verify them hypothesis:(1)Alxa desert rodents with different biological characteristics and life history strategies have different niche divisions in different dimensions;(2)Environmental heterogeneity causes rodents to redistribute and utilize existing resources,resulting in new resource allocation patterns in multiple niche dimensions.Finally,the coexistence mechanism of desert rodents is revealed.The main results are as follows.1.The spatial niche overlap between the Siberian jerboa and the other three rodent species was very low;midday gerbil and northern three-toed jerboa have wide distribution characteristics,and have different degrees of niche overlap with other rodents.The evenness of rodent communities is closely related to the spatial distribution of rodents,and habitat concealment is a key factor affecting the spatial occupation of rodents.2.The activity rhythm patterns of midday gerbil,northern three-toed jerboa,and siberian jerboa were similar.Desert hamster reduce competition with the other three rodent species by temporal niche segregation and staggered peak activity.Temperature is an important factor affecting the temporal niche of rodent.Vegetation height directly affects the number of rodent populations,and indirectly affects their foraging activities through predation risk.3.The trophic level of the siberian jerboa is significantly higher than that of other rodent,and its trophic niche is significantly separated from other rodent species.The northern threetoed jerboa increases its food resources by expanding the feeding range,and the feeding range and trophic niche area are larger than the other three rodent.Plant biomass has a positive effect on the nitrogen stable isotope value of the Siberian jerboa,but has a negative effect on the nitrogen stable isotope value of the midday gerbil.rodent diversity has a negative effect on the nutritional niche width of midday gerbil,northern three-toed jerboa,and desert hamster.4.The spatial pattern and dynamics of the four rodents coexisting in the desert are mainly regulated by the midday gerbil and the northern three-toed jerboa.midday gerbil is dominant factor affecting the spatial pattern of community in desert.midday gerbils have stronger temporal niche stability,weaker sensitivity to environmental changes and higher resistance.The trophic niche stability of Siberian jerboa is the highest,and the individual recipes in the population had little difference.5.The strategies of spatial heterogeneity hypothesis and niche variation hypothesis were adopted in the spatial dimension of rodent community pattern in desert areas;in the temporal dimension,The strategy of temporal niche separation is adopted;The strategy of feeding habits separation and optimal foraging theory is adopted in trophic niche.