Conversion of Andean montane forest to exotic forest plantation modifies soil physicochemical properties in the buffer zone of Ecuador's Podocarpus National Park

Background:Andean montane forests(AMF)are biodiversity hotspots that provide fundamental hydrological services as well as carbon storage and sequestration.In recent decades,southern Ecuador AMFs have been seriously threatened by increased logging and conversion to forest plantations with exotic species.In this context,our main objective was to evaluate the effects of AMF conversion to forest plantations on soil physicochemical properties in the buffer zone(Bz)of the Podocarpus National Park(PNP),in southern Ecuador.For this purpose,random samples were taken at a depth of 0-10 cm in four plots in each contrast zone and analyzed for bulk density,porosity,textural class,leaf litter depth,soil pH,as well as the contents of organic matter(SOM),soil organic carbon(SOC),total nitrogen,and available phosphorus and potassium.Results:The results indicate that the conversion of AMFs produces an increase in bulk density and a decrease in SOM,SOC,and total nitrogen contents,thus modifying soil properties,which could result in a decrease in water regulation capacity and produce an increased risk of soil erosion.This accelerates degradation processes,as well as threatens shortages of the drinking water supply.Conclusions:This study can help decision-makers to implement soil management plans in the Bz of the PNP,based on the implementation of new regulations,where the conservation of AMF is promoted.In addition,it is recommended to apply environmental restoration strategies in the anthropized areas of the AMF,as well as in the areas with exotic eucalyptus and pine plantations.

Effects of land use on the Soil Organic Carbon storage potentiality and soil edaphic factors in Tripura, Northeast India

The regulatory functions of soil are getting attention among the scientists and Soil Organic Carbon (SOC) is an important indicator of soil health. The impact of differential use of land on SOC and other edaphic properties were analysed in three important Land use land cover (LULC) system of Tripura, northeast India. Soil cores were divided into four depth profiles (0 - 10, 10 - 30, 30 - 50 and 50 - 100 cm) to observe the changes of edaphic properties into the soil depth gradient. Our results suggest that SOC in the top profile of Managed Plantation (MP) and Jhum Fellow (JF) was 51.68% and 48.55%, less than Natural Forest (NF). From 0 - 10 to 10 - 30 cm soil depth, 43.3%, 8.4% and 39.4% decrease in NF MP and JF found. Total stock of SOC (Mg C·ha﹣1) was found highest in JF (121.87), followed by NF (117.12) and MP (85.34). In top profile, conversion of NF into MP and NF into JF led to 39% and 11% decrease in SOC. The significant variation in SOC stock was found among different LULC under this study (F2,12 = 16.94, P ≤ 0.001). In 0 - 10 cm soil depth, maximum value of bulk density (gm·cm﹣3) was found in MP (1.39) followed by JF (1.27) and NF (1.23). In top profile, significant variation was found among LULC (p < 0.001). Soil pH and moisture content significantly varied (p < 0.05) in 0 - 10, 10 - 30 and 50 - 100 cm soil depth. In contrast to that significant change in soil temperature was found at 30 - 50 cm (p < 0.001) and 50 - 100 cm (p < 0.001). It was observed that JF had highest overall SOC stock than NF and MP. Conversion of NF into MP and JF results significant loss of SOC at 0 - 10 and 10 - 30 cm depth profile. We also found that NF conversion had significant impact on the change in the soil C pool.

Rhizosphere fungal community assembly varied across functional guilds in a temperate forest

Background Rhizosphere fungi play an important role in plant community dynamics and biogeochemical cycling.While the drivers of fungal community assembly have been studied in varied ecosystems,it is still unclear how these processes function for rhizosphere soil fungi in temperate forests.Furthermore,it is unknown whether the relative contributions of important determinants remain consistent or vary across fungal ecological guilds.This study used high-throughput next-generation sequencing to characterize the fungal communities of 247 rhizosphere soil samples from 19 tree species in a temperate forest within Northeast China.We aimed to investigate how three important determinants in temperate forests(host tree species,neighbouring plant communities,and edaphic properties)influence the community assembly of fungal functional guilds in the rhizosphere soil of trees.Results We found that host tree species contributed more to plant pathogens’community composition than ectomycorrhizal fungi,and plant pathogens consistently showed higher host specialization than ectomycorrhizal fungi.Saprotrophs also showed high host specialization,which was mediated by the tree species’effect on rhizosphere soil pH.Although neighboring plant communities contributed remarkably to richness of all fungal guilds,this effect on fungal composition varied across functional guilds,with stronger effect for biotrophic guilds(plant pathogens and ectomycorrhizal fungi)than for non-biotrophic guild(saprotrophs).Neighboring plant communities shaped the ectomycorrhizal community composition strongly in all samples regardless of host trees’mycorrhizal type,whereas edaphic properties were the most important drivers for this guild in samples from only ectomycorrhizal-associated trees.Edaphic properties played an important role in shaping ectomycorrhizal and saprotrophic fungal compositions,indicating the importance of edaphic properties on the fungal functional guilds associated with the absorption and decomposition of nutrients.Conclusions These results demonstrated that rhizosphere soil fungal community assembly determinants varied across fungal guilds,reflecting their different ecological functions in temperate forest ecosystems.