This study evaluated impacts of Coriaria nepalensis Wall.colonization on soil characteristics,vegetation structure and composition,regeneration status and expected future compositional changes,biomass and carbon stock...This study evaluated impacts of Coriaria nepalensis Wall.colonization on soil characteristics,vegetation structure and composition,regeneration status and expected future compositional changes,biomass and carbon stock in tree species of a mixed conifer forest of Central Himalaya.Three sites(1 ha each in an old landslide area)differing in Coriaria density(low:20 individuals ha^(-1);medium:120 indiv.ha^(-1);high:190 indiv.ha^(-1))were used to enumerate the tree species.A total of 9 tree species and 2830 individuals were recorded from the three study sites that represented a gradient of Coriaria density.Number of species varied from 3 to 7 and the individuals from 690 to 1270 per site with lowest numbers at low Coriaria density and highest at medium Coriaria density.The number of seedlings increased with increasing Coriaria density,and the sites were unique in their seedling composition,indicating marked temporal dynamics.Site wise regeneration analysis showed that regeneration was poor at the site with low Coriaria density and good at the high-density site where many species emerged as seedlings.These results indicate that the ameliorative effects of Coriaria in terms of soil buildup,and accumulation of nutrients and organic matter helped more species to colonize the area.This facilitative ability of Coriaria can be used to restore degraded forest ecosystems of Indian Central Himalaya.展开更多
Invasive plant Ageratina adenophora(Sprengel)R.King&H.Robinson has invaded majority of the temperate forests in Kumaun,Central Himalaya.Information on A.adenophora invaded forest types,their structural attributes,...Invasive plant Ageratina adenophora(Sprengel)R.King&H.Robinson has invaded majority of the temperate forests in Kumaun,Central Himalaya.Information on A.adenophora invaded forest types,their structural attributes,population demography and regeneration status are still at rudimentary level.Considering this,the present study was conducted to assess the impacts of A.adenophora on vegetational attributes and regeneration status of three forest types,viz.,Oak(Quercus oblongata D.Don),Pine(Pinus roxburghii Sarg.)and Cypress(Cupressus torulosa D.Don).We selected three sites for each forest type and each site was further purposively stratified into paired sampling plots of 1 ha each i.e.,A.adenophora invaded and uninvaded sites.Our results showed large densities of cut stumps or felled trees throughout invaded sites,but with fewer fire signs in comparison to uninvaded sites.In uninvaded sites,total density and basal area calculated for woody species were relatively higher than those in invaded sites,although results were insignificant(p>0.05).With the exception for Cypress forests,vegetation indices showed low woody species richness and diversity in invaded Oak and Pine forests.Also,regeneration of Q.oblongata,P.roxburghii and C.torulosa tree species did not differ significantly(p>0.05)between invaded and uninvaded sites.These insignificant differences clearly imply that A.adenophora's presence has not entirely changed the perennial plant communities in terms of composition,structure and natural regeneration.However,tree species with poor or no regeneration status requires special attention and needs management strategies involving control of invasive species in forest ecosystems.展开更多
Introduction:In Central Himalaya,anthropogenic activities have led to the widespread replacement of Banj oak(Quercus leucotrichophora)forest by Chir pine(Pinus roxburghii)for decades.This study was conducted to determ...Introduction:In Central Himalaya,anthropogenic activities have led to the widespread replacement of Banj oak(Quercus leucotrichophora)forest by Chir pine(Pinus roxburghii)for decades.This study was conducted to determine how natural Banj oak,Chir pine,and mixed oak-pine forest would differ in soil microbial biomass and soil nutrients.Soil microbial biomass nitrogen(SMBN)and phosphorus(SMBP),soil organic carbon(SOC)total nitrogen(TN),and total phosphorus(TP)in the 0 to 15 cm soil layer were investigated in the Central Himalayan region in the stands of Banj oak,mixed oak-pine,and Chir pine forest.Results:The SMBN and SMBP were significantly higher in Banj oak and mixed oak-pine forest as compared to Chir pine forest.The ratios of SMBN to TN(SMBN/TN)and SMBP to TP(SMBP/TP)were significantly higher in the Chir pine forest,indicating that in this forest,the proportion of microbial biomass N and P to total soil N and P was higher as compared to Banj oak forest.A similar pattern of variation was found in relation to season across the forests,all with an apparent peak in the rainy season.Conclusion:These results indicate that low microbial biomass N and P may be one of the reasons to create a nutrient poor site in Chir pine forest.The collection of pine litter by local people also impairs the return of nutrients to the soil and makes it difficult for Banj oak to re-invade areas occupied by Chir pine.This calls for cautions in large-scale conversions of the Banj oak forests to coniferous plantations as a forest management practice on concerns of sustaining soil productivity.展开更多
基金partially supported by a project grant from University Grant Commission,New Delhi
文摘This study evaluated impacts of Coriaria nepalensis Wall.colonization on soil characteristics,vegetation structure and composition,regeneration status and expected future compositional changes,biomass and carbon stock in tree species of a mixed conifer forest of Central Himalaya.Three sites(1 ha each in an old landslide area)differing in Coriaria density(low:20 individuals ha^(-1);medium:120 indiv.ha^(-1);high:190 indiv.ha^(-1))were used to enumerate the tree species.A total of 9 tree species and 2830 individuals were recorded from the three study sites that represented a gradient of Coriaria density.Number of species varied from 3 to 7 and the individuals from 690 to 1270 per site with lowest numbers at low Coriaria density and highest at medium Coriaria density.The number of seedlings increased with increasing Coriaria density,and the sites were unique in their seedling composition,indicating marked temporal dynamics.Site wise regeneration analysis showed that regeneration was poor at the site with low Coriaria density and good at the high-density site where many species emerged as seedlings.These results indicate that the ameliorative effects of Coriaria in terms of soil buildup,and accumulation of nutrients and organic matter helped more species to colonize the area.This facilitative ability of Coriaria can be used to restore degraded forest ecosystems of Indian Central Himalaya.
基金Department of Science&Technology,New Delhi(DST-SERB/CRG/2019/004139)for providing financial support。
文摘Invasive plant Ageratina adenophora(Sprengel)R.King&H.Robinson has invaded majority of the temperate forests in Kumaun,Central Himalaya.Information on A.adenophora invaded forest types,their structural attributes,population demography and regeneration status are still at rudimentary level.Considering this,the present study was conducted to assess the impacts of A.adenophora on vegetational attributes and regeneration status of three forest types,viz.,Oak(Quercus oblongata D.Don),Pine(Pinus roxburghii Sarg.)and Cypress(Cupressus torulosa D.Don).We selected three sites for each forest type and each site was further purposively stratified into paired sampling plots of 1 ha each i.e.,A.adenophora invaded and uninvaded sites.Our results showed large densities of cut stumps or felled trees throughout invaded sites,but with fewer fire signs in comparison to uninvaded sites.In uninvaded sites,total density and basal area calculated for woody species were relatively higher than those in invaded sites,although results were insignificant(p>0.05).With the exception for Cypress forests,vegetation indices showed low woody species richness and diversity in invaded Oak and Pine forests.Also,regeneration of Q.oblongata,P.roxburghii and C.torulosa tree species did not differ significantly(p>0.05)between invaded and uninvaded sites.These insignificant differences clearly imply that A.adenophora's presence has not entirely changed the perennial plant communities in terms of composition,structure and natural regeneration.However,tree species with poor or no regeneration status requires special attention and needs management strategies involving control of invasive species in forest ecosystems.
文摘Introduction:In Central Himalaya,anthropogenic activities have led to the widespread replacement of Banj oak(Quercus leucotrichophora)forest by Chir pine(Pinus roxburghii)for decades.This study was conducted to determine how natural Banj oak,Chir pine,and mixed oak-pine forest would differ in soil microbial biomass and soil nutrients.Soil microbial biomass nitrogen(SMBN)and phosphorus(SMBP),soil organic carbon(SOC)total nitrogen(TN),and total phosphorus(TP)in the 0 to 15 cm soil layer were investigated in the Central Himalayan region in the stands of Banj oak,mixed oak-pine,and Chir pine forest.Results:The SMBN and SMBP were significantly higher in Banj oak and mixed oak-pine forest as compared to Chir pine forest.The ratios of SMBN to TN(SMBN/TN)and SMBP to TP(SMBP/TP)were significantly higher in the Chir pine forest,indicating that in this forest,the proportion of microbial biomass N and P to total soil N and P was higher as compared to Banj oak forest.A similar pattern of variation was found in relation to season across the forests,all with an apparent peak in the rainy season.Conclusion:These results indicate that low microbial biomass N and P may be one of the reasons to create a nutrient poor site in Chir pine forest.The collection of pine litter by local people also impairs the return of nutrients to the soil and makes it difficult for Banj oak to re-invade areas occupied by Chir pine.This calls for cautions in large-scale conversions of the Banj oak forests to coniferous plantations as a forest management practice on concerns of sustaining soil productivity.
