川西林盘木本植物多样性对人为干扰的响应

【目的】针对川西林盘受到破坏、植物群落稳定性减弱等现状,开展干扰强度对川西林盘木本植物多样性的研究,为提出川西林盘的保护和合理利用提供依据。【方法】以成都市城乡建设委员会绘制的成都市林盘分布图为基础,根据分布,采用样线法选择了183个典型川西林盘,利用现场调查开展研究。【结果】①从物种数量比例看,乔木占比高于灌木,拥有较大的生长空间,在人为干扰下依然保持着优势。②从干扰程度与植物占比的相关性表明:人为干扰程度与乔木占比不显著,人为干扰程度与灌木占比呈正相关关系,乔木占比与灌木占比呈负相关关系。③在控制了灌木与乔木间的交互影响后,则表现为人为干扰对乔木占比呈正相关;控制乔木占比这一变量,对相关性的结果影响不大。【结论】乔木是林盘的主要物种,并占据主导空间;人为干扰有助于乔木和灌木等木本植物在川西林盘中的分布。

四川白玉拉龙措国家湿地公园植被调查及分析

对四川白玉拉龙措国家湿地公园的植物种类及植被类型进行调查,结果表明:湿地公园共有高等植物66科174属377种,以被子植物居多,占总种数的91.78%;湿地植物共计21科27属46种,以莎草科最多,其次为灯心草科;湿地公园分布有国家I级重点保护植物1种、国家II级重点保护植物2种、珍稀濒危植物5种及中国特有植物5种;从种子植物属的区系分布来看,地理成分较为复杂,植物区系具有典型的温带属性;湿地公园自然植被可分为5个植被型组,7个植被型,19个群系,无栽培植被;植被调查结果显示,以灌丛、草甸和沼泽占绝对优势,共计17个群系,占总群系的89.47%,其中,温泉水绵沼泽是目前中国少数几个湿地公园拥有的湿地植被类型。

雨强和坡度对嵌套砾石工程边坡侵蚀特征的影响

为探究不同雨强和坡度对西南高山-亚高山地区急陡、高砾石含量工程边坡土壤侵蚀的影响.采用室内模拟降雨及人工配置土壤等方法,在5种雨强(25,40,45,65,85 mm/h),5种坡度(35°,40°,45°,50°,60°)条件下进行模拟实验.研究结果表明:工程坡面产流率随着雨强的增加呈对数增加.不同雨强下坡面平均产流率变化过程随着坡度的变化差异性具有统计学意义.随着雨强的增加,同一坡面工程边坡侵蚀率明显增多.当雨强为40 mm/h时,工程坡面侵蚀率随坡度变化较小(<0.015 g/s);当雨强为65 mm/h时,同一坡面的侵蚀率随着坡度的增加而减少.工程坡面溅蚀率整体呈现出迅速增长至峰值后缓慢下降的趋势.同一边坡随着雨强的增加,坡面击溅侵蚀率在产流前和产流时都有明显的增加,不同粒径土壤增速具有明显差异,同一坡面随着坡度的增加,坡面泥沙溅蚀率存在临界值(40°~45°).降雨强度与土壤侵蚀相关性有统计学意义,不同雨强下坡度与径流过程和侵蚀过程的相关性具有明显差异性.结论:工程边坡中砾石具有增加下渗率和抗侵蚀作用,工程坡面土壤侵蚀率随降雨历时逐渐下降;坡度的增加在增大坡面流速的同时会降低坡面实际承雨面积,工程坡面土壤侵蚀率随坡度的增加呈非线性关系.

Microclimate regulation efficiency of the rural homegarden agroforestry system in the Western Sichuan Plain,China

Traditional rural homegarden agroforestry systems(referred to as homegarden) in the Western Sichuan Plain of China are often referred to as "Linpan" in Chinese. These homegardens are usually composed of farm houses, trees, bamboos, and small patches of land for flowers, fruits and vegetables. Over the Western Sichuan Plain’s area of approximately 18,800 km^2, there were more than 200,000 homegardens, accommodating 72.5% of the region’s rural population. As a unique local, cultural, and ecological resource, homegardens continuously support peasant households with provisioning, regulation, and landscape ecosystem services. This study combined low height remote sensing used unmanned aerial vehicle(UAV) photography, field investigation, and instrument monitoring. We try to identify the composition and structural characteristics of homegardens, as well as climatic regulation effects of the different types of homegardens. Temperature data were collected both for summer(June to August 2016) and winter(December 2016 to February 2017). The result shows that:(1) the average area of homegardens was 0.67 ha(sizes ranging from 0.16 ha to 1.24 ha), and with vegetation coverage 43.5%-76.9%(including 310 plant species).(2)In comparision with outside the homegardens, the average temperature inside the homegardens was significantly lower in summer(approximately 0.31 ℃-0.90 ℃). Although, the lowest summer temperature was differentiatee in between 13:30-16:00. Especially, the thermal effects of the home gardens were ranged from 2.00℃-2.65℃ at high temperatures(≥30℃).(3) The cooling effect of homegardens were positively correlated(p<0.05) with tree area(X_1), vegetation coverage(X_2), tree coverage(X_3), tree species(X_4), and tree biomassper unit area(X_5), and the contribution rate was represented by X_3>X_4>X_5>X_2>X_1.(4)This study indicates the major role of homegardens for climate regulation and energy efficiency, providing suggestions for homegarden transformation and construction planning for new rural communities.

Spatial-temporal dynamics of alpine grassland coverage and its response to climate warming in Mt.Qomolangma Nature Preserve during 2000-2019

The Qinghai-Tibet Plateau(QTP)has the largest and highest alpine grassland ecosystem in the world,which is considered to be the most sensitive and vulnerable ecosystem to climate change.Its dynamic changes and driving mechanism have always been widely researched.The Qomolangma National Nature Preserve(QNNP),with the largest altitude difference in the world,was selected as the study area to analyse the spatial-temporal dynamics of grassland coverage and the different characteristics of elevation gradients at the southern slope(SS)and northern slope(NS)with MODIS MOD13Q1 NDVI and MOD11A2 land surface temperature data from 2000to 2019 using the Mann-Kendall trend test and Theil-Sen slope methods.Further,the response mechanism of grassland coverage to climate warming is discussed.The results revealed that from 2000 to 2019,the grassland coverage change in the study area is mainly stable.The increased area proportion of grassland coverage on the southern slope is significantly higher than that on the northern slope,and the decreased area proportion of grassland coverage on the northern slope is significantly greater than that on the southern slope.The change characteristics of grassland coverage in the QNNP exhibit an obvious elevation gradient;the higher the elevation,the greater the increased area proportion of grassland coverage,particularly on the SS.The land surface temperature can be used as a proxy for analysing the temporal and spatial variation trends of air temperature in the QNNP.With the increase of the altitude,the land surface temperature rise rate on both the southern slope and northern slope exhibited an increasing trend,and the sensitivity of grassland coverage to temperature rise was higher on the northern slope.The water condition was the decisive factor for the horizontal and vertical spatial heterogeneity of the dynamic change of grassland coverage,and the melting of glaciers and thawing of permafrost were important sources of water for grassland growth in the QNNP.Climate warming promotes the growth of grassland in areas with a sufficient water supply,but adversely affects the growth of grassland in areas with insufficient water supplies,which will be further intensified by human activities.

Relationship between High-quality Tea and the Geological Background in Qionglai Mountains

[Objective] Many strata emerge in the high-quality tea producing area in Qionglai Mountains,which belongs to Mesozoic Cretaceous(K),Mingshan Fm(E1-2mn)and Dayi conglomerate Team(N)of Cenozoic Tertiary System as well as Quaternary System(Q).Analysis on the migrating features of soil heavy metal from each stratum to tea leaves showed that the enrichment ability of elements was Cu>Cd>Zn>Ni>Hg>As>Cr>Pb.By comparing the soil background values with the soil base values of Sichuan hilly area and Chengdu economic region,it could be concluded that Cd,Hg,Mo,Pb and Se were enriched,and other metal elements existed at a level close to that of the comparing areas.The pH was a little acidic,and high quality tea cultivation could be developed here at present.With the increase of human activities,the environment of study area tends to deteriorate.Therefore,land planning and use should be reasonable.The government should control the environment nearby and prevent pollution.

坡度与坡位对工程创面土壤养分状况的影响研究

为探明四川二郎山西坡318国道沿线工程创面生态和土壤修复状况,了解工程创面坡度与坡位对土壤养分状况的影响,用现场调查和工程创面土壤采样、分析测定pH值、有机质等9个指标的方法,进行了相关研究。结果表明,修复15年以上的工程创面土壤养分含量水平总体上还不及自然坡面,养分水平偏低;坡度对创面土壤养分影响较大,35°~40°坡面土壤养有机质、全氮、全磷、碱解氮、速效钾含量均大于40°~45°坡面,35°~40°坡面土壤全钾、有效磷含量则小于40°~45°坡面;坡位对工程创面土壤养分影响则较小。

长时间修复工程创面与自然坡面土壤肥力对比研究

为探究长时间修复工程创面土壤肥力特征,通过对二郎山西坡318国道沿线较长修复年限的工程创面及其附近自然坡面各土壤肥力指标研究,结果表明:在土壤肥力指标上,工程创面整体低于自然坡面,pH值、有机质、全氮、全磷、全钾、有效磷、含水量两者差异显著。坡位对土壤肥力指标在均值上有影响,总体表现为下坡>中坡>上坡,但工程创面上仅土壤含水量的上、下坡差异显著,自然坡面有机质、全氮、含水量上、下坡间差异显著。各指标中pH值、有机质、全磷及含水量是影响工程创面土壤肥力的主要因子;有机质、全氮、全磷及有效磷是影响自然坡面土壤肥力的主要因子。