Dynamics of iron and aluminum storages in a subtropical forest headwater stream

The forest headwater streams are important hubs for connecting terrestrial and aquatic ecosystems,with plant litter and sediments as the major carriers for material migrations;however,until now we knew little about the dynamics of trace elements such as iron(Fe)and aluminum(Al)in forest headwater streams.Here,we quantitatively identified the spatiotemporal dynamics of Fe and Al storages in plant litter and sediments and their influencing factors in a subtropical forest headwater stream,and assessed the potential pollution risk.The results showed that:(1)the mean concentrations of Fe and Al in plant litter(sediments)were 5.48 and 8.46(7.39 and 47.47)g·kg^(-1),and the mean storages of Fe and Al in plant litter(sediments)were 0.26 and 0.43(749.04 and 5030.90)g·m^(-2),respectively;(2)the storages of Fe and Al in plant litter and sediments significantly fluctuated from January to December,and showed a decreasing pattern from the source to mouth;and(3)storages of Fe and Al had no significant correlation with riparian forest type and the present of tributary and the Fe and Al storages in plant litter were mainly affected by water temperature and water alkalinity,and their storages in sediments were mainly affected by water temperature and frequency of rainfall;and(4)there were no anthropogenic pollution in Fe and Al in the forest headwater stream.Our study revealed the primary factors of concentrations and storages of Fe and Al in plant litter and sediments in a forest headwater stream,which will improve our understanding of the role of headwater streams in forest nutrient storage and cycling along with hydrological processes.

森林碳汇市场综述

本文从森林碳汇的概念和碳汇市场的必要性、可行性及特征进行概述,提出了碳汇的意义。同时分析了森林碳汇的市场及政府政策中现有的森林碳汇交易机制和国际市场运行机制,以及未来碳交易市场发展面临的主要挑战与展望。

亚拉冲村苗族村寨社区旅游发展探讨

以文山市亚拉冲苗族社区为对象,调查社区内及周边的自然资源和人文资源现状,实地走访后结合SWOT法分析社区旅游发展的优、劣势及面临的机遇与困难。提出通过强化区域旅游规模化、注重旅游市场开发、改善社区旅游目的地支撑条件等措施,实现社区旅游的旅游目的地经济效益、环境效益和社会效益的协调统一和资源最优化配置,推动民族社区特色旅游的健康持续发展。

植被恢复对矿区土壤微生物群落结构影响的整合分析

采矿对土壤生态系统造成严重破坏,针对废弃矿区进行植被恢复成为可持续发展的必然要求。土壤微生物作为土壤有机质最活跃的组成部分,是参与碳、氮、磷等元素转化的重要动力,常被用作表明生态脆弱区植被恢复程度的指标。但全球尺度上植被恢复对矿区土壤微生物群落结构的影响仍缺乏了解。本文基于44篇论文的310个成对观测值,采用整合分析的方法,分析植被恢复对矿区土壤微生物数量与生物量的影响。结果表明:矿区植被恢复对土壤微生物生物量具有显著的促进作用,与裸地相比,植被恢复使矿区土壤微生物生物量碳显著提高95.1%,土壤微生物生物量氮显著提高87.8%,土壤细菌、真菌、放线菌数量分别显著提高1005.4%、472.4%和177.7%。各种植被恢复模式中,单独种植乔木的恢复模式对土壤微生物生物量和数量的促进效果最为明显,使土壤真菌与放线菌数量分别提升540.3%和104.5%,微生物生物量碳和氮分别提升110.3%和106.4%。模型选择的结果显示,饱和土壤含水量和植被恢复年限均对土壤细菌和真菌数量贡献最大,土壤有效氮对土壤放线菌数量和土壤微生物生物量碳影响最显著,土壤有效磷则是土壤微生物生物量氮的重要影响因子。研究结果有助于了解矿区植被恢复与土壤微生物群落结构的关系,为确定合适的矿区植被恢复模式提供科学支撑。

中亚热带不同森林类型对地表径流磷动态的影响

磷是亚热带森林生产力的主要限制因子之一,其随地表径流的输出是森林磷流失的重要途径,且可能受不同森林类型的显著调控,但缺乏必要关注.着眼于中亚热带不同类型森林的地表径流,分析米槠(Castanopsis carlesii)人工幼林、杉木(Cunninghamia lanceolata)人工幼林、米槠次生林及杉木人工成熟林对地表径流总磷浓度及输出的影响,为深入认识亚热带森林磷迁移过程及有效森林经营提供一定科学基础数据.结果显示:(1)不同森林类型的地表径流产流量大小为米槠人工幼林(1506.06±5.18 m^(3)/hm^(2))>杉木人工幼林(971.56±2.88 m^(3)/hm^(2))>米槠次生林(552.85±2.45 m^(3)/hm^(2))>杉木人工成熟林(468.83±1.81 m^(3)/hm^(2));(2)不同森林类型地表径流总磷浓度之间存在显著差异,表现为米槠次生林(0.239±0.093 mg/L)>杉木人工成熟林(0.138±0.042 mg/L)>杉木人工幼林(0.064±0.033 mg/L)>米槠人工幼林(0.057±0.040 mg/L);(3)4种类型森林地表径流磷输出量为米槠次生林(124.54±1.53 g/hm^(2))>米槠人工幼林(93.24±0.98)g/hm^(2)>杉木人工幼林(72.11±0.1.22 g/hm^(2))>杉木人工成熟林(56.49±0.49 g/hm^(2));(4)4种类型森林的地表径流量与降水之间均存在极显著(P<0.01)的相关关系.上述结果表明不同森林类型磷随地表径流的输出差异显著,阔叶林磷随地表径流的流失可能显著大于针叶林.(图3表2参34)