Vegetation types alter soil ecosystems by changing soil fauna community activities and soil physi-cal-chemical properties.However,it is unclear how tree species(natural forest,native and exotic tree plantations)promot...Vegetation types alter soil ecosystems by changing soil fauna community activities and soil physi-cal-chemical properties.However,it is unclear how tree species(natural forest,native and exotic tree plantations)promote changes in the soil ecosystem,and if these changes alter functional groups of soil fauna and ecosystem services.To determine the effects of five decades of old-field veg-etation on soil ecosystems in the Brazilian Atlantic Forest,field sampling of three ecosystems(exotic tree species Pinus elliottii Engelm.plantation,endangered tree species Arau-caria angustifolia(Bertol.)Kuntze plantation,and a natural ecosystem)were carried out,as well using bait-lamina tests and bioassays with collembolans,earthworms and seeds of Lactuca sativa L.Field sampling evaluated the soil fauna community and soil physical-chemical properties.The bait-lamina test in situ was carried out for 14-days to deter-mine fauna feeding activity,and the bioassays evaluated the reproduction of Folsomia candida,the avoidance of Eisenia andrei,and germination of L.sativa in the soil from each ecosystem.The results are:(1)vegetation type altered the soil fauna community composition;(2)soil fauna feeding was reduced in the plantations compared to the natural eco-system;(3)a physical barrier was created by recalcitrant litter that compromised fauna community structure and seed bank germination in situ;and,(4)changes in soil physical-chemical properties promoted decomposers.展开更多
The allometric relationships between growth traits are critical to trees’fitness,yet the mechanisms by which slope position affects tree growth and allometry remain poorly understood.This study examined growth traits...The allometric relationships between growth traits are critical to trees’fitness,yet the mechanisms by which slope position affects tree growth and allometry remain poorly understood.This study examined growth traits and their allometric relationships in an 8-year-old Calocedrus macrolepis plantation in southwest China across three slope positions(upslope,mesoslope and downslope).The measured growth traits included tree height(H),diameter at breast height(D),crown size(Crown),wood volume(V)and height under branch(HUB).The study also explored spatial variations in soil properties and microbial communities.Results showed that slope position altered allometric growth pattern,with larger allometric exponents at downslope for H,D and V relative to Crown and HUB,suggesting improved wood growth.Soil nutrient levels(nitrogen,phosphorus and available potassium)and microbial diversity,particularly the relative abundance of bacterial phyla such as Actinobacteria and Chloroflexi,were greater at mesoslope and downslope.Our study identified phosphorus and potassium as key drivers of enhanced allometric relationships.Functional groups such as Endomycorrhizal and Ectomycorrhizal fungi,and functional groups involved in nitrogen cycling(Nitrogen respiration,Nitrate respiration),were strongly correlated with allometric exponents for D,V and Crown relative to HUB,suggesting their role in supporting structural growth and canopy expansion.These findings emphasize that variations in soil nutrients and microbial communities across slope positions regulate tree growth and allometry,with bacterial communities exerting a stronger influence than fungi.These insights contribute to sustainable forest management,particularly in optimizing planting site selection for improved tree growth in mountainous regions.展开更多
文摘Vegetation types alter soil ecosystems by changing soil fauna community activities and soil physi-cal-chemical properties.However,it is unclear how tree species(natural forest,native and exotic tree plantations)promote changes in the soil ecosystem,and if these changes alter functional groups of soil fauna and ecosystem services.To determine the effects of five decades of old-field veg-etation on soil ecosystems in the Brazilian Atlantic Forest,field sampling of three ecosystems(exotic tree species Pinus elliottii Engelm.plantation,endangered tree species Arau-caria angustifolia(Bertol.)Kuntze plantation,and a natural ecosystem)were carried out,as well using bait-lamina tests and bioassays with collembolans,earthworms and seeds of Lactuca sativa L.Field sampling evaluated the soil fauna community and soil physical-chemical properties.The bait-lamina test in situ was carried out for 14-days to deter-mine fauna feeding activity,and the bioassays evaluated the reproduction of Folsomia candida,the avoidance of Eisenia andrei,and germination of L.sativa in the soil from each ecosystem.The results are:(1)vegetation type altered the soil fauna community composition;(2)soil fauna feeding was reduced in the plantations compared to the natural eco-system;(3)a physical barrier was created by recalcitrant litter that compromised fauna community structure and seed bank germination in situ;and,(4)changes in soil physical-chemical properties promoted decomposers.
基金supported by the Essential Scientific Research of Chinese National Nonprofit Institute(CAFYBB2021ZW003)National Natural Science Foundation of China(32022058)+1 种基金the Candidates of the Young and Middle-Aged Academic Leaders of Yunnan Province of China(202205AC160041)Yunnan Fundamental Research Projects(202201AT070258 and 202301AV070002)and Xingdian Talent Support Program(XDYC-QNRC-2022-0231).
文摘The allometric relationships between growth traits are critical to trees’fitness,yet the mechanisms by which slope position affects tree growth and allometry remain poorly understood.This study examined growth traits and their allometric relationships in an 8-year-old Calocedrus macrolepis plantation in southwest China across three slope positions(upslope,mesoslope and downslope).The measured growth traits included tree height(H),diameter at breast height(D),crown size(Crown),wood volume(V)and height under branch(HUB).The study also explored spatial variations in soil properties and microbial communities.Results showed that slope position altered allometric growth pattern,with larger allometric exponents at downslope for H,D and V relative to Crown and HUB,suggesting improved wood growth.Soil nutrient levels(nitrogen,phosphorus and available potassium)and microbial diversity,particularly the relative abundance of bacterial phyla such as Actinobacteria and Chloroflexi,were greater at mesoslope and downslope.Our study identified phosphorus and potassium as key drivers of enhanced allometric relationships.Functional groups such as Endomycorrhizal and Ectomycorrhizal fungi,and functional groups involved in nitrogen cycling(Nitrogen respiration,Nitrate respiration),were strongly correlated with allometric exponents for D,V and Crown relative to HUB,suggesting their role in supporting structural growth and canopy expansion.These findings emphasize that variations in soil nutrients and microbial communities across slope positions regulate tree growth and allometry,with bacterial communities exerting a stronger influence than fungi.These insights contribute to sustainable forest management,particularly in optimizing planting site selection for improved tree growth in mountainous regions.
