Excessive acid deposition causes soil acidification, and changes the soil microhabitat, thus affecting the survival and reproduction of soil organisms. Folsomia candida (Collembola, Isotomidae), as a model organism, is widely used to assess the chemical toxicity in soil, and its avoidance response can indicate the environmental changes. In this study, we used Folsomia candida to assess the risks of acid deposition on soil ecosystems. Different pH (3.0, 3.5, 4.0, 4.5, 5.0, and 5.5) treatments were set up in petri dish experiments, and the avoidance behavior of Folsomia candida was measured after 12, 24, and 48 h exposure to the pH conditions. The results indicated that (1) both the exposure duration and pH level influenced avoidance behavior of collembolan. (2) After 12 h exposure, most of the individuals showed avoidance behavior but without significant differences among the treatments. (3) After 24 h exposure, significant avoidance behavior was observed at pH 3.0, 3.5, and 4.0. (4) After 48 h exposure, avoidance behavior was found in all treatment conditions except for pH 5.5. This study clarified the direct responses of soil fauna to acid deposition, and indicated that both pH and length of exposure influenced the avoidance behavior of Folsomia candida. During the experimental period, the collembolan reacted negatively and showed consistent avoidance behavior at pH 3.0, 3.5, and 4.0. Reversed avoidance behavior was apparent between pH 4.5 and 5.0 and not observed at pH 5.5, indicating that the latter was the preferred pH environment.

There has been a recent increase in interest on how urbanization affects soil fauna communities. However, previous studies primarily focused on some limited land use types or line transects of urban-rural gradients. At family and higher taxonomic levels, we investigated the changes of soil mesofauna communities (abundance, species richness, and community structure) with urbanization intensity along different disturbance features in 47 sites evenly located in downtown Guangzhou and adjacent regions. The 47 research sites were classified into four ecosystem types mainly according to the location (rural/urban), vegetation cover, and management intensity. In turn, the four types with increasing urbanization intensity were rural forest, urban forest, urban woodland, and urban park. Firstly, the role of urban soil property (soil physicochemical characteristic and soil heavy metal content) in regulating soil mesofauna community was investigated. The results showed that soil mesofauna abundance and diversity decreased with increasing soil pH, total nitrogen content (TN), and heavy metal comprehensive index (CPI). Soil Pb decreased soil mesofauna species richness (taxa number) and regulated soil mesofauna community structure. Secondly, we examined the effects of landscape changes on the soil mesofauna community. We found impervious surface (IS) ratio did not predict changes in soil mesofauna abundance, species richness, or community structure. Instead, IS ratio was positively correlated with soil pH, soil TN, and CPI. After excluding sites that belonged to rural forests and urban parks, site area was positively correlated with soil mesofauna abundance. Thirdly, our results revealed significant differences in soil property, landscape trait, and soil mesofauna community among the four ecosystem types. Interestingly, urban forest, the one lightly disturbed by urbanization, but not rural forest, had the highest soil mesofauna abundance. Soil mesofauna abundance in urban woodlands was similar to that in urban parks, which was about half of that in urban forests. Species richness in urban parks was 21% lower than that in rural forests. Our results also showed that urban woodland and urban parks had distinct mesofauna community structures compared to those in rural forests and urban forests. In conclusion, the present study suggested that (1) soil property changes due to urbanization, such as increased pH and heavy metal enrichment in urban soil, decreased soil mesofauna abundance and species richness, changed community structure, and mediated the effect of landscape change on soil mesofauna community; (2) however, soil and landscape changes could not explain the increase of abundance in urban forests, which supported the intermediate disturbance hypothesis.

土壤微塑料污染已引起国内外学者的广泛关注.但关于次生微塑料在土壤动物食物链上的迁移及其毒理效应的研究较少.为探究次生微塑料的生物传递效应,本试验以同步化14 d(幼虫)和28 d(成虫)的土壤白符跳(Folsomia Candida)为供试生物,将废料(塑料类废料混合物)、保温棉、麦麸保温棉混合和细保温棉经黄粉虫(Tenebrio molitor Linnaeus)降解后形成的4种不同次生微塑料产物作为处理因子,研究次生微塑料对土壤跳虫生物学的影响.结果发现:1)第7天,所有跳虫开始蜕皮,喂食保温棉、麦麸保温棉和细保温棉组的幼虫死亡率分别为1.67％、1.67％和5％;2)第14天,跳虫蜕皮量增多,保温棉和细保温棉组的幼虫死亡率分别为6.67％和5％,各组成虫产卵量剧增,喂食酵母菌的对照组产卵率显著高于处理组;3)第28天,蜕皮量增势趋缓,除废料组外,各组幼虫开始产卵且无死亡现象发生;4)与处理组相比,对照组中跳虫的蜕皮量、产卵量和生物量都是最高的,且体长变化显著(P＜0.05).综上,研究结果将进一步完善次生微塑料对土壤动物毒理效应的基础数据,为土壤环境中的次生微塑料的生态风险评价提供理论依据.

为了找出较为适宜上海青生长的栽培基质,利用腐叶土、泥炭土、蛭石、珍珠岩、椰糠5种材料混配成不同的基质类型,并设置添加或不添加微生物菌剂处理,比较试验基质理化性质的差异及其与微生物菌剂协同作用对上海青生长的影响.结果显示:不同基质之间除通气孔隙度外,理化性质均存在显著差异,且其对上海青生长指标有极显著影响(p<0.001);添加菌剂对基质理化性质没有显著影响,但同一基质类型中添加菌剂使上海青鲜重提高了24％～153％,能显著促进上海青的生长.上海青的生长指标与基质pH值和EC值显著正相关,与总孔隙度、持水孔隙度显著负相关.本研究认为较适合上海青生长的栽培基质为腐叶土+菌剂、腐叶土+泥炭土+菌剂.

为探索防治桔小实蝇的新途径,开展了辽细辛提取物对桔小实蝇成虫的引诱作用研究及田间防治试验.结果表明:辽细辛提取物对桔小实蝇成虫有强烈的引诱作用;辽细辛提取物能有效降低杨桃园桔小实蝇成虫种群数量,与对照区相比,防治区虫果率大大降低,防治效果达90％以上;用GC-MS方法测定辽细辛提取物的化学成分,其中左旋-β-蒎烯、左旋-α-蒎烯、杜仲酮、3,5-二甲氧基甲苯、黄樟脑、甲基丁香酚、3,4,5-三甲氧基甲苯、肉豆蔻醚等8种成分的相对含量较高,均大于2％.

[目的]初步了解惠州地区桔小实蝇的野生寄主植物.[方法]以象头山、罗浮山等为中心,调查该地区内自然生长的植物上桔小实蝇的为害情况,将发现的桔小实蝇成虫或虫果带回实验室进行镜检,为害程度则根据受害率进行分级.[结果]桔小实蝇的寄主植物19科41属68种;其中桃金娘科和芸香科寄主植物受害程度最高,桑科寄主植物种类最多.各种植物的受害期不同,并在其中转移为害,世代繁衍.[结论]该研究为桔小实蝇防控提供理论依据.

人地关系是新时代地理学综合研究的核心,而快速发展的城市化促进了人地矛盾的集中体现.同时,土壤圈是地球关键带中最活跃的圈层,在城市环境中成为人-地联系活跃的生态环节.城市表层土壤在区域小尺度水平人-地联系中具有重要意义,但对其生态界面意义还未有专门的论述.虽然现在已有较多的学者研究报道了城市化进程中土壤性质变化、重金属和有机污染等问题,但对其中的源-汇正负反馈效应仍然认识不足.为了城市的可持续发展,各种生态健康评价研究蓬勃开展.其中,土壤动物特有的生物学属性和环境敏感性,使之成为城市环境变化和生态健康风险评价优良的综合性指示因子,然而相关的研究比较缺乏.因此,本文就城市表层土壤对生态健康影响的研究进行了述评.城市表层土壤既是生物的聚居地,又与城市大气、水体存在密切的互作交流关系,对城市人类活动具有积极的正负反馈作用,成为城市人-地联系的关键生态界面.城市化背景下土壤表层生物、理化性质的变化不仅对土壤健康造成威胁,同时也增加了人居健康风险.最后,本文对相关研究进行了展望,提出未来应加强城市表层土壤的生态界面效应研究,在研究方法上要建立长期、多尺度的城市土壤研究计划,以及推进区域城市表层土壤动物生物学、生态学研究等.