This paper deals with the initial boundary value problem for a class of nonlinear Kirchhoff-type equations with strong dissipative and source terms in a bounded domain, where and are constants. We obtain the global ex...This paper deals with the initial boundary value problem for a class of nonlinear Kirchhoff-type equations with strong dissipative and source terms in a bounded domain, where and are constants. We obtain the global existence of solutions by constructing a stable set in and show the energy exponential decay estimate by applying a lemma of V. Komornik.展开更多
Many alpine ecosystems are undergoing vegetation degradation because of global changes,which are affecting ecosystem functioning and biodiversity.The ecological consequences of alpine pioneer community degradation hav...Many alpine ecosystems are undergoing vegetation degradation because of global changes,which are affecting ecosystem functioning and biodiversity.The ecological consequences of alpine pioneer community degradation have been less studied than glacial retreat or meadow degradation in alpine ecosystems.We document the comprehensive responses of microbial community characteristics to degradation processes using field-based sampling,conduct soil microcosm experiments to simulate the effects of global change on microorganisms,and explore their relationships to ecosystem functioning across stages of alpine pioneer community degradation.Our work provides the first evidence that alpine pioneer community degradation led to declines of 27%in fungal richness,8%in bacterial richness,and about 50%in endemic microorganisms.As vegetation degraded,key ecosystem functions such as nutrient availability,soil enzymatic activity,microbial biomass,and ecosystem multifunctionality progressively increased.However,soil respiration rate and carbon storage exhibited unbalanced dynamics.Respiration rate increased by 190%during the middle stage of degradation compared with the primary stage,and it decreased by 38%in the later stage.This indicates that soil carbon loss or emission increases during the mid-successional stage,whereas in later successional stages,alpine meadows become significant carbon sinks.Compared with microbial community characteristics(such as richness of total and functional taxa,and network complexity),community resistance contributes more significantly to ecosystem functions.Especially,the bacterial community resistance is crucial for ecosystem functioning,yet it is greatly impaired by nitrogen addition.Based on microbial network,community assembly,and community resistance analyses,we conclude that fungi are more vulnerable to environmental changes and show smaller contributions to ecosystem functions than bacteria in degrading alpine ecosystems.Our findings enhance the knowledge of the distinct and synergistic functional contributions of microbial communities in degrading alpine ecosystems and offer guidance for developing restoration strategies that optimize ecosystem functioning of degraded alpine plant communities.展开更多
The initial-boundary value problem for semilinear wave equation systems with a strong dissipative term in bounded domain is studied.The existence of global solutions for this problem is proved by using potential well ...The initial-boundary value problem for semilinear wave equation systems with a strong dissipative term in bounded domain is studied.The existence of global solutions for this problem is proved by using potential well method,and the exponential decay of global solutions is given through introducing an appropriate Lyapunov function.Meanwhile,blow-up of solutions in the unstable set is also obtained.展开更多
文摘This paper deals with the initial boundary value problem for a class of nonlinear Kirchhoff-type equations with strong dissipative and source terms in a bounded domain, where and are constants. We obtain the global existence of solutions by constructing a stable set in and show the energy exponential decay estimate by applying a lemma of V. Komornik.
基金supported by the Yunnan Applied Basic Research Project(202401CF070057)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502)+4 种基金the National Natural Science Foundation of China(32171552)the Preparatory Talents for Yunnan Middle-Age and Young Academic&Technology Champions Project(202205AC160053)Yunnan Revitalization Talent Support Program“Young Talent”ProjectIntroducing talents start-up fund of Kunming Institute of Botany,Chinese Academy of SciencesYunnan Caiyun Postdoctor Program。
文摘Many alpine ecosystems are undergoing vegetation degradation because of global changes,which are affecting ecosystem functioning and biodiversity.The ecological consequences of alpine pioneer community degradation have been less studied than glacial retreat or meadow degradation in alpine ecosystems.We document the comprehensive responses of microbial community characteristics to degradation processes using field-based sampling,conduct soil microcosm experiments to simulate the effects of global change on microorganisms,and explore their relationships to ecosystem functioning across stages of alpine pioneer community degradation.Our work provides the first evidence that alpine pioneer community degradation led to declines of 27%in fungal richness,8%in bacterial richness,and about 50%in endemic microorganisms.As vegetation degraded,key ecosystem functions such as nutrient availability,soil enzymatic activity,microbial biomass,and ecosystem multifunctionality progressively increased.However,soil respiration rate and carbon storage exhibited unbalanced dynamics.Respiration rate increased by 190%during the middle stage of degradation compared with the primary stage,and it decreased by 38%in the later stage.This indicates that soil carbon loss or emission increases during the mid-successional stage,whereas in later successional stages,alpine meadows become significant carbon sinks.Compared with microbial community characteristics(such as richness of total and functional taxa,and network complexity),community resistance contributes more significantly to ecosystem functions.Especially,the bacterial community resistance is crucial for ecosystem functioning,yet it is greatly impaired by nitrogen addition.Based on microbial network,community assembly,and community resistance analyses,we conclude that fungi are more vulnerable to environmental changes and show smaller contributions to ecosystem functions than bacteria in degrading alpine ecosystems.Our findings enhance the knowledge of the distinct and synergistic functional contributions of microbial communities in degrading alpine ecosystems and offer guidance for developing restoration strategies that optimize ecosystem functioning of degraded alpine plant communities.
基金This research was supported by the Natural Science Foundation of Zhejiang Province(Grant No.LY17A010009).
文摘The initial-boundary value problem for semilinear wave equation systems with a strong dissipative term in bounded domain is studied.The existence of global solutions for this problem is proved by using potential well method,and the exponential decay of global solutions is given through introducing an appropriate Lyapunov function.Meanwhile,blow-up of solutions in the unstable set is also obtained.
