Species-habitat Associations In A Temperate Old-Growth Forest Of Northeastern China

Species coexistence mechanisms and the maintenance of biodiversity have long been important components of community ecology research.At present,niche theory and neutral theory constitute the most interesting researched theories in this area.At present,there were few studies on the relative importance of niche theory and neutral theory in maintaining the biodiversity and species coexistence in tropical and subtropical forests.Studying the pattern of death and recruitment of forest species in temperate forests was of great important to understand and predict ecological problems such as population dynamics,forest succession and species regeneration.In this study,33 woody plants with DBH ? 1 cm and ? 30 individuals in the plot were selected based on the census data of the 30-ha dynamics plot of typical mixed broadleavedKorean pine(Pinus koraiensis)forest in Fenglin in 2014.The torus-translation test was used to analyze the association of different species,life stages(sapling,juvenile and mature),life forms(shrubs,trees)and growth habits(light-demanding,midtolerant,shade-tolerant)within five habitats.Of the 33 species we tested,28 species(84.8%)were at least significantly associated with one habitat type.Positive associations were more frequent in the valley and slope(shady and sunny)and less frequent in the ridge.A total of 32 significant positive associations with the five habitats were observed at the three life stages(10,11 and 11 at the sapling,juvenile,and mature stages,respectively).The majority of species' habitat preferences shifted among different life stages;the exceptions were Corylus mandshurica,Maackia amurensis,Quercus mongolica and Picea jezoensis,which had consistent associations with the same habitat at all stages.The trees were positively associated with the valley and the shrubs were positively associated with the sunny.The midtolerant trees and midtolerant shrubs were correlated positively with the sunny areas across the three life stages.The species composition and community structure of different habitats,the individual density of ridges,sunny and shady were larger,and the number of individuals with lightdemanding recruitment species was less than that of midtolerant species,shade-tolerant species.Of the 10 species with the largest number of deaths,8 of them were 10 species with the largest number of individuals in the sample.The analysis of the habitat association of different species,growth habits,life forms dead and recruitment species found that,19(90.5%)recruitment species was significantly associated with at least one habitat,and the 22(84.6%)dead species was significantly associated with at least one habitat.Our results indicated that species exhibited the characteristics of habitat specialization and that habitat partitioning played an important role in the coexistence of species.Species-habitat associations changed ontogenetically.Different habitat conditions affected the composition of the species and the recruitment and death of the community.Habitat filtration has a greater impact on the recruitment and death of temperate forest species,affecting the change of community structure and forest dynamics.