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731.
Responses of waterbirds to flooding in an arid region of Australia and implications for conservation
Floods are a frequent but irregular feature of Australia's dryland river catchments. We investigated changes in abundances of waterbirds in north western New South Wales with changes in wetland distribution at local, catchment and broad scales. The abundance of most functional groups of waterbirds changed in response to broad scale changes in wetland distribution, while local abundance remained highly variable. Patterns of abundance varied among functional groups of waterbirds, with some immediately responding to changes in wetland distribution and area flooded, and others apparently responding to sequences of wetting and drying. In Australia, the main conservation issue for waterbirds is water and its use across the landscape and not the spatial arrangement of any fixed array of reserves established to protect them. 相似文献
732.
733.
Influence of inoculation with arbuscular mycorrhizal fungi on stable isotopes of nitrogen in Phaseolus vulgaris 总被引:1,自引:0,他引:1
D. Redecker P. von Berswordt-Wallrabe D. P. Beck D. Werner 《Biology and Fertility of Soils》1997,24(3):344-346
The interactions between Phaseolus vulgaris, Rhizobium spp. strains nodulating P. vulgaris, and arbuscular mycorrhizal (AM) fungi were assessed under greenhouse conditions in a nonsterilized Typic Haplustalf soil
from Cauca, Colombia. Our results indicate a specific involvement of AM fungal species in nitrogen acquisition by the legume
plants from symbiotic nitrogen fixation and from soil. A significant specific influence of inoculation with Glomus spp. on the 15N/14N ratio in plant shoots was dependent on the inoculated rhizobial strain, but AM fungal inoculation had no significant effect
on shoot dry weight or nodule occupancy in the two different rhizobial strain treatments. The results imply that in low P
soils the effects of an improved mycorrhizal symbiosis may include improved symbiotic N2 fixation efficiency and/or improved soil N uptake.
Received: 11 May 1996 相似文献
734.
Takashi IKEDA Makoto ASANO Masatsugu SUZUKI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(5):846
There is a possibility that classical swine fever (CSF) virus outbreak has negative impacts on wild boar. To adequately manage native wild boar populations, wildlife managers need to gather the field data on wild boar and implement population management practices. We aimed to report the relative abundance index of wild boar before and after this outbreak. Our results showed that relative abundance index declined from 2017 (8.88 wild boars/100 trap days) to 2019 (2.03 wild boars/100 trap days), because of the negative impact of this virus and continuous culling programs. Although the eradication risk from the synergistic effect is low, wildlife managers need to consider the relationship between the trade-off between the risk of CSF and the conservation ecology risk of native species eradication. 相似文献
735.
Mukhtar Musa Festo Massawe Sean Mayes Ibraheem Alshareef 《Communications in Soil Science and Plant Analysis》2016,47(4):533-542
Bambara groundnut has great potential as an alternative crop for improving food security in its production regions and beyond. A field experiment was conducted at the Field Research Centre of the Crops for the Future to obtain information on the nitrogen (N) fixation and N balance of Bambara groundnut landraces on tropical acidic soils of Malaysia. Treatments consisted of three Bambara groundnut landraces (Ex-Sokoto, Kaaro, and NN-1) laid out in a randomized complete block design replicated three times. Results obtained revealed that Ex-Sokoto landrace was greater in yield and N fixation, whereas N balance (-haulm) was greater in NN-1 landrace. The results revealed grain yield of 703–2256 kg ha?1 and N fixation from 32–81 kg ha?1 and suggest that Bambara groundnut could be integrated into a cereal-based cropping system. Ex-Sokoto landrace appeared to be the most promising for yield and N fixation under Malaysian acidic soil conditions. 相似文献
736.
This study describes a novel approach to separate three soil carbon (C) sources by one tracer method (here 13C natural abundance). The approach uses the temporal dynamics of the CO2 efflux from a C3 grassland soil amended with added C3 or C4 slurry and/or C3 or C4 sugar to estimate contributions of three separate C sources (native soil, slurry, and sugar) to CO2 efflux. Soil with slurry and/or sugar was incubated under controlled conditions, and concentration and δ13C values of evolved CO2 were measured over a 2‐week period. The main assumption needed for separation of three C sources in CO2 efflux, i.e., identical decomposition of applied C3 and C4 sugars in soil, was investigated and proven. The relative contribution to the CO2 efflux was higher, but shorter with an increased (microbial) availability of the C source, i.e., sugar > slurry > SOM. The shortcomings and limitations as well as possible future applications of the suggested method are discussed. 相似文献
737.
珍稀濒危植物长苞铁杉群落物种多度分布模型研究 总被引:2,自引:0,他引:2
用Weibull分布模型拟合珍稀濒危植物长苞铁杉群落物种多度分布结果表明 ,长苞铁杉群落乔木层、灌木层物种多度分布均符合Weibull分布 ,Weibull分布模型应用于珍稀濒危植物长苞铁杉群落物种多度分布具可行性 相似文献
738.
Reedbeds have high conservation value in Europe. In southern France, they are the major breeding habitat of five passerine species. Yet, habitat management is done primarily by water control to serve socio-economic rather than conservation interests, because we lack information on the species' ecological requirements. Determinants of passerine abundance were assessed through a comparative analysis of water regime, plant structure, and arthropod (food) distribution at 12 sites consisting of at least 10 ha of marsh densely covered with common reed (Phragmites australis). Overall bird abundance estimated through standardised mist netting was positively correlated with food availability (sweep-netted arthropods weighted by their occurrence in birds' diet), which was in turn negatively correlated with duration of ground dryness between June and December. Abundance of four of the five bird species was associated with specific vegetation parameters (reed diameter, dry reed density, growing reed height, etc.), which could be associated with particular management practices, especially with regard to water levels and salinity. Potential impact of socio-economic activities through their water management is addressed, as well as possible ways to minimise these impacts. 相似文献
739.
土壤多样性: 中国山东省基于1:100万比例尺的SOTER的实例研究 总被引:6,自引:0,他引:6
The diversity of soils derived from different parent materials and developed on different terrains inShandong Province, China, was analyzed with the theory of pedodiversity using a 1:1000000 scale soilsand terrain digital database (SOTER) of Shandong Province in a geographical information system (GIS)environment. Diversity index of soils derived from different parent materials followed the sequence of igneousrock > sedimentary rock > metamorphic rock > unconsolidated material. Diversity index of soils developedon different terrains followed the sequence of plain > medium-gradient mountain > medium-gradient hill> valley floor > medium-gradient escarpment zone > depression > high-gradient mountain. Abundancedistributions of these soil groups matched the logarithmic normal distributions. 相似文献
740.
苜蓿土壤氮磷钾丰缺指标初步研究 总被引:6,自引:2,他引:6
选取综合肥力差异较大的5种农田土壤,安排全肥(适量N,P,K肥)、缺氮、缺磷、缺钾盆栽试验,依据第一年干草产量用养分丰缺法确定了种植新牧1号紫花苜蓿土壤的氮、磷、钾丰缺指标。盆栽试验结果表明:种植新牧1号紫花苜蓿,土壤碱解氮含量10~21mg·kg-1为缺、21~29mg·kg-1为中、29~40mg·kg-1为丰,大于40mg·kg-1为极丰;土壤速效磷含量3.3~7.7mg·kg-1为缺、7.7~11.3mg·kg-1为中、11.3~17.8mg·kg-1为丰,大于17.8mg·kg-1为极丰;土壤速效钾含量49~123mg·kg-1为缺、123~191mg·kg-1为中、191~338mg·kg-1为丰,大于338mg·kg-1为极丰。 相似文献