The Research On The Associations Of Population Dynamics And Spatial Distribution Between Rodents And Seed Plants In Forests

Forest is one of the largest and most important terrestrial ecosystems.As important components of forest animal and plant communities,rodents and plants play nonnegligible roles in maintaining forest biodiversity and stability,and their spatiotemporal associations are also central topics in ecology.Rodents interact with seed plants as both seed predators and seed dispersers,so their population dynamics and spatial distribution are closely related.Meanwhile,climate is found to be one important factor affecting their population dynamics and spatial distribution.However,previous studies mainly focused on local scales and a few taxa,lacking a large-scale analysis of the associations of population dynamics and spatial distribution between rodents and seed plants.Based on a broad literature review and data compilation,we built three databases containing coupled long-term time series of seed abundances and rodent populations,rodent-seed plant interactions and spatial distribution of rodents and plants(Plants from Arecaceae,Fagaceae,Pinaceae were chosen for their high occurrence frequency and representativeness),and explored two questions.(1)For population dynamics,do mast seeding events trigger rodent population outbreaks,and how do density dependence,seed production and climate affect rodent population dynamics?(2)How do interaction types and climate change affect the spatial overlap and relative richness of rodents and seed plants?(1)Through cooccurrence analysis and population dynamic models,we found 29 of 66 rodent populations showed statistically significant coincidence between rodent outbreak and mast-seeding years.The relative importance of density dependence was the dominant factor affecting rodent population growth rates.The relative importance of seed abundance decreased,but that of rodent density dependence increased with the latitude of study.Climate factors have shown weak cascading effects on seed production and rodent population dynamics.(2)Based on the databases of rodent-seed plant interaction and spatial distribution,we found the spatial overlap of mutualists in family Fagaceae was higher than that of antagonists,while interaction types showed an opposite effect in Arecaceae.As climate change became more serious,the spatial overlap of mutualistic rodents and plants in Arecaceae would decrease significantly while that in the other two families of plants showed no significant change.At the community level,the hot spots of species richness for rodents and seed plants were similar,but the relative richness of rodents(rodent minus seed plant)was found mismatched.For mutualistic rodents and seed plants,the relative richness of rodents increased with latitude in northern hemisphere,but showed an opposite trend in southern hemisphere;for antagonistic rodents and seed plants,the relative richness of rodents decreased with latitude in both northern and southern hemisphere.As climate warming pressure increased,the spatial distribution of rodents and plants would both move north,and rodents would move faster and more,thus the relative richness of rodents would increase with climate warming at high latitudes.For the first time,this study elaborated on the associations of population dynamics and spatial distribution between rodents and seed plants on a global scale.These results may help to understand the dynamics of rodent populations and the mechanism of rodent outbreaks as well as how plant-animal communities respond to climate change,also providing fundamental data and theoretical guidance for pest rodent control and biodiversity protection.