The soils in the South China Sea Islands (SCSI) were divided into three types, namely, phospho-calc soils,skeletisols and coastic solonchaks, which were derived from bio-clastic and strongly calcareous sediments. Inco...The soils in the South China Sea Islands (SCSI) were divided into three types, namely, phospho-calc soils,skeletisols and coastic solonchaks, which were derived from bio-clastic and strongly calcareous sediments. Incomparison with their parent materials, the phospho-calc soils have higher contents of P, Zn, Cu, Ba, and Cd,which tend to increase gradually with time, and lower contents of Mg, Ca, Sr, B, V, Pb, and Mo, which tendto decrease by degrees with time. The above-mentioned constitnents in skeletisols and coastic solonchaks aresimilar to those in their parent materials except for P and Na. The factors atfecting element distribution aremainly special bioclimate and parent material, meanwhile, resulting in the remarkable iulluence on elementdistribution through soil-forming time.展开更多
Aims Plant-pollinator interaction networks are dynamic entities,and seasonal variation in plant phenology can reshape their structure on both short and long timescales.However,such seasonal dynamics are rarely conside...Aims Plant-pollinator interaction networks are dynamic entities,and seasonal variation in plant phenology can reshape their structure on both short and long timescales.However,such seasonal dynamics are rarely considered,especially for oceanic island pollination networks.Here,we assess changes in the temporal dynamics of plant-pollinator interactions in response to seasonal variation in floral resource richness in oceanic island communities.Methods We evaluated seasonal variations of pollination networks in the Yongxing Island community.Four temporal qualitative pollination networks were analyzed using plant-pollinator interaction data of the four seasons.We collected data on plant-pollinator interactions during two consecutive months in each of the four seasons.Four network-level indices were calculated to characterize the overall structure of the networks.Statistical analyses of community dissimilarity were used to compare this community across four seasons to explore the underlying factors driving these patterns.We also evaluated the temporal variation in two species-level indices of plant and pollinator functional groups.Important Findings Both network-level specialization and modularity showed a significantly opposite trend compared with plant species richness across four seasons.Increased numbers of plant species might promote greater competition among pollinators,leading to increased niche overlap and causing decreased specialization and modularity and vice versa.Further analyses suggested that the season-to-season turnover of interactions was dominated by interaction rewiring.Thus,the seasonal changes in niche overlap among pollinators lead to interaction rewiring,which drives interaction turnover in this community.Hawkmoths had higher values of specialization and Apidae had higher values of species strength compared with other pollinator functional groups.These findings should be considered when exploring plant-pollinator interactions in ecosystems of isolated oceanic islands and in other ecosystems.展开更多
Aims With the increase of land-use change,habitat fragmentation has become a major factor affecting plant diversity.Generally,when the adult density is high,the survival rate of conspecific saplings may decline and pr...Aims With the increase of land-use change,habitat fragmentation has become a major factor affecting plant diversity.Generally,when the adult density is high,the survival rate of conspecific saplings may decline and provide more resources and space for other species to maintain a high local species diversity.Therefore,the spatial relationship of conspecific saplings and adults(SRCSA)can regulate plant diversity.However,very few studies have assessed SRCSA within fragmented forests,and we still largely unknown the relationship between SRCSA and species diversity in fragmented landscapes.Methods We calculated the mean strength of SRCSA using the spatial distribution data of saplings and adults with a log-transformed hierarchical offset-power model on 27 islands in a land-bridge island system.The higher strength of SRCSA reflects a more negative relationship between the density of conspecific saplings and adults on an island(i.e.the looser pattern of SRCSA).We tested the relationships among island attributes(i.e.island area,the distance to the mainland—MD,and the distance to the nearest island—ND),SRCSA and species diversity.Important Findings The strength of SRCSA increased with ND.Meanwhile,the species diversity significantly increased with the strength of SRCSA,and island area and the strength of SRCSA independently explained 26%and 6%of variation of species diversity,respectively,and their interactions explained 8%.Shade-intolerant and low-abundant species showed looser patterns of SRCSA.Our study suggests that SRCSA may have the effect of excluding species with a relatively low abundance in isolated island forests,which illustrates the importance of biotic interactions in maintaining plant diversity in fragmented forests.Our results also emphasize that we should consider forest connectivity when testing the conspecific negative density dependence.展开更多
文摘The soils in the South China Sea Islands (SCSI) were divided into three types, namely, phospho-calc soils,skeletisols and coastic solonchaks, which were derived from bio-clastic and strongly calcareous sediments. Incomparison with their parent materials, the phospho-calc soils have higher contents of P, Zn, Cu, Ba, and Cd,which tend to increase gradually with time, and lower contents of Mg, Ca, Sr, B, V, Pb, and Mo, which tendto decrease by degrees with time. The above-mentioned constitnents in skeletisols and coastic solonchaks aresimilar to those in their parent materials except for P and Na. The factors atfecting element distribution aremainly special bioclimate and parent material, meanwhile, resulting in the remarkable iulluence on elementdistribution through soil-forming time.
基金supported by the National Natural Science Foundation of China(grant no.31800447)the Chinese Academy of Sciences(grant no.XDA13020504)+1 种基金the Natural Science Foundation of Guangdong Province(grant no.2018A030310385)the National Natural Science Foundation of China(grant no.U1701246).
文摘Aims Plant-pollinator interaction networks are dynamic entities,and seasonal variation in plant phenology can reshape their structure on both short and long timescales.However,such seasonal dynamics are rarely considered,especially for oceanic island pollination networks.Here,we assess changes in the temporal dynamics of plant-pollinator interactions in response to seasonal variation in floral resource richness in oceanic island communities.Methods We evaluated seasonal variations of pollination networks in the Yongxing Island community.Four temporal qualitative pollination networks were analyzed using plant-pollinator interaction data of the four seasons.We collected data on plant-pollinator interactions during two consecutive months in each of the four seasons.Four network-level indices were calculated to characterize the overall structure of the networks.Statistical analyses of community dissimilarity were used to compare this community across four seasons to explore the underlying factors driving these patterns.We also evaluated the temporal variation in two species-level indices of plant and pollinator functional groups.Important Findings Both network-level specialization and modularity showed a significantly opposite trend compared with plant species richness across four seasons.Increased numbers of plant species might promote greater competition among pollinators,leading to increased niche overlap and causing decreased specialization and modularity and vice versa.Further analyses suggested that the season-to-season turnover of interactions was dominated by interaction rewiring.Thus,the seasonal changes in niche overlap among pollinators lead to interaction rewiring,which drives interaction turnover in this community.Hawkmoths had higher values of specialization and Apidae had higher values of species strength compared with other pollinator functional groups.These findings should be considered when exploring plant-pollinator interactions in ecosystems of isolated oceanic islands and in other ecosystems.
基金supported by the Key Research and Development Program of Zhejiang Province(No.2017C02028)the National Natural Science Foundation of China(No.31930073,31870401 and 31901104)+1 种基金the National Key Research and Development Project(2018YFE0112800)the Fundamental Research Funds for the Central Universities(2019QNA6002).
文摘Aims With the increase of land-use change,habitat fragmentation has become a major factor affecting plant diversity.Generally,when the adult density is high,the survival rate of conspecific saplings may decline and provide more resources and space for other species to maintain a high local species diversity.Therefore,the spatial relationship of conspecific saplings and adults(SRCSA)can regulate plant diversity.However,very few studies have assessed SRCSA within fragmented forests,and we still largely unknown the relationship between SRCSA and species diversity in fragmented landscapes.Methods We calculated the mean strength of SRCSA using the spatial distribution data of saplings and adults with a log-transformed hierarchical offset-power model on 27 islands in a land-bridge island system.The higher strength of SRCSA reflects a more negative relationship between the density of conspecific saplings and adults on an island(i.e.the looser pattern of SRCSA).We tested the relationships among island attributes(i.e.island area,the distance to the mainland—MD,and the distance to the nearest island—ND),SRCSA and species diversity.Important Findings The strength of SRCSA increased with ND.Meanwhile,the species diversity significantly increased with the strength of SRCSA,and island area and the strength of SRCSA independently explained 26%and 6%of variation of species diversity,respectively,and their interactions explained 8%.Shade-intolerant and low-abundant species showed looser patterns of SRCSA.Our study suggests that SRCSA may have the effect of excluding species with a relatively low abundance in isolated island forests,which illustrates the importance of biotic interactions in maintaining plant diversity in fragmented forests.Our results also emphasize that we should consider forest connectivity when testing the conspecific negative density dependence.
