Strategic Management of an Invasive Ant‐scale Mutualism Enables Recovery of a Threatened Tropical Tree Species

Mutualisms between invasive ants and honeydew‐producing insects can have widespread negative effects on natural ecosystems. This is becoming an increasingly serious problem worldwide, causing certain ecosystems to change radically. Management of these abundant and influential mutualistic species is essential if the host ecosystem is to recover to its former non‐invaded status. This negative effect is particularly prevalent on some tropical islands, including Cousine Island, Seychelles. On this island, the invasive ant Pheidole megacephala has caused serious indirect damage to the threatened native Pisonia grandis trees via a mutualism with an invasive scale insect, Pulvinaria urbicola. We aimed to suppress the ant, thereby decoupling the mutualism and enabling recovery of the Pisonia trees. We treated all areas where ant pressure was high with a selective formicidal bait, which was deployed in custom‐made bait stations designed to avoid risk of treatment to endemic fauna. In the treated area, ant foraging activity was reduced by 93 percent and was followed by a 100 percent reduction in scale insect density. Abundance of endemic herbivorous insects and herbivorous activity increased significantly, however, after the decline in mutualistic species densities. Despite the native herbivore increase, there was considerable overall improvement in Pisonia shoot condition and an observed increase in foliage density. Our results demonstrate the benefit of strategic management of highly mutualistic alien species to the native Pisonia trees. It also supports the idea that area‐wide suppression is a feasible alternative to eradication for achieving positive conservation management at the level of the forest ecosystem.     

Modelled biophysical impacts of conservation agriculture on local climates

Including the parameterization of land management practices into Earth System Models has been shown to influence the simulation of regional climates, particularly for temperature extremes. However, recent model development has focused on implementing irrigation where other land management practices such as conservation agriculture (CA) has been limited due to the lack of global spatially explicit datasets describing where this form of management is practiced. Here, we implement a representation of CA into the Community Earth System Model and show that the quality of simulated surface energy fluxes improves when including more information on how agricultural land is managed. We also compare the climate response at the subgrid scale where CA is applied. We find that CA generally contributes to local cooling (~1°C) of hot temperature extremes in mid‐latitude regions where it is practiced, while over tropical locations CA contributes to local warming (~1°C) due to changes in evapotranspiration dominating the effects of enhanced surface albedo. In particular, changes in the partitioning of evapotranspiration between soil evaporation and transpiration are critical for the sign of the temperature change: a cooling occurs only when the soil moisture retention and associated enhanced transpiration is sufficient to offset the warming from reduced soil evaporation. Finally, we examine the climate change mitigation potential of CA by comparing a simulation with present‐day CA extent to a simulation where CA is expanded to all suitable crop areas. Here, our results indicate that while the local temperature response to CA is considerable cooling (>2°C), the grid‐scale changes in climate are counteractive due to negative atmospheric feedbacks. Overall, our results underline that CA has a nonnegligible impact on the local climate and that it should therefore be considered in future climate projections.     

不同人为干扰措施对天然次生灌丛土壤肥力及蓄水能力的影响

亚热带常绿阔叶林遭反复干扰后退化形成的天然次生灌丛在未管护模式下难以恢复为乔木林。在浙江省临安市选择典型天然次生灌丛,以强度人为干扰为对照、分别进行保护性干扰和适度人为干扰,探讨灌丛土壤蓄水能力和肥力质量的响应。4年试验结果表明:与强度人为干扰相比,保护性干扰和适度人为干扰后的土壤总贮水量、吸持贮水量和滞留贮水量分别提高了12.41%、5.33%、17.37%和29.13%、33.23%和26.24%;最大持水量、毛管持水量和最小持水量分别提高了23.35%、9.51%、17.55%和48.63%、56.08和71.05%;与强度人为干扰相比,保护性干扰和适度人为干扰的综合肥力分别提高了1.9%和38.5%,其中保护性干扰的水解氮、有机碳和有机质含量提高了12.11%、38.91%和38.94%,适度人为干扰的水解氮、有效磷、有机碳和有机质含量提高了61.97%、90.57%、130%和130.04%,保护性干扰和适度人为干扰的土壤综合评价指数分别提高了15.43%和58.94%。研究表明,与保护性干扰相比,适度人为干扰在土壤的蓄水保水、肥力和固碳增汇等方面更能达到预期的目标。在有条件经营的情况下,可以选择适度人为干扰措施对天然次生灌丛进行管理从而达到加快土壤恢复的目的。     

椰子叶螨Aceria(Eriophyes)guerreronis对我国椰子产业的风险性分析

[目的]明确刺吸式害虫椰子叶螨对我国椰子产业的风险,为该虫的检验检疫和应急防控提供参考.[方法]从椰子叶螨的国内外发生现状、潜在危害性、受害作物的经济重要性、定殖扩散的可能性以及风险管理的难度等方面,对椰子叶螨危害我国椰子产业的风险性进行定性和定量评估.[结果]椰子叶螨个体较小、传播方式多样、检疫和灭除难度较大,根据有...     

Mass‐trapping trials for the control of pine processionary moth in a pine woodland recreational area

The pine processionary moth, Thaumetopoea pityocampa, causes serious defoliation to Cedrus, Pinus and Pseudotsuga trees, as well as health problems in humans, pets and farm animals due to their urticating hairs. Environmentally friendly strategies for the management of T. pityocampa include: removal of egg batches, removal of nests, trapping of migrant larvae, spraying microbial or Insect Growth Regulator (IGR) insecticides and biocontrol, as well as pheromone‐based adult trapping and mating‐disruption. In the present paper, results on innovative technology for the control of T. pityocampa infestation using pheromone mass‐trapping are reported. Two 1‐ha plots were identified in the study area (central‐south Italy), a pine woodland recreational site growing Pinus halepensis. In the experimental plot (MT‐plot), 10 G‐traps (funnel trap type) baited with (Z)‐13‐hexadecen‐11‐ynyl acetate sex pheromone component were placed for mass‐trapping of adults; the other plot was used as a control‐plot (C‐plot). The T. pityocampa population was monitored using the two central traps in the MT‐plot and two traps positioned in the C‐plot. In addition, the winter nests made by T. pityocampa larvae overwintering on pine trees were counted. After 2 years of mass‐trapping, the number of adults trapped by the monitoring pheromone traps decreased in the MT‐plot, but not in the C‐plot, whereas the number of nests decreased in both plots. Statistical results highlighted significant differences in trap catches between the two plots but not between years. In the case of nests, differences among plots were not significant before the mass‐trapping, but significant after 1‐year treatment. According to our results, the mass‐trapping technique is able to reduce T. pityocampa infestations. This pheromone method can be applied in combination with other control systems in the context of integrated pest management in recreational areas.     

广西石山人工林灌草多样性与环境因子的关系

以广西石山人工林群落调查数据为材料,采用双向指示种分类(TWINSPAN)、冗余分析(RDA)和典范对应分析(CCA)研究了9个生境变量、1林分类型因子与石山人工林多样性、草本和灌木植物组成的关系。结果表明,坡位是影响石山人工林物种组成多样性的最主要因子,露石率和坡度对石山人工林林下有害物种分布影响最大。石山人工林林下植被组成的主要决定因素是生境因子(解释率23%~55%),而树种选择是次要因素(解释率11%~17%)。石山梯地人工林的有害草本种类多于坡地,梯地的有害灌木种类少于坡地。石山人工林的有害植物种类少于封山育林地。     

Performance and financial consequences of stillbirth in Holstein dairy cattle

Stillbirth is an economically important trait on dairy farms. Knowledge of the consequences of, and the economic losses associated with stillbirth can help the producer when making management decisions. The objectives of this study were to determine the effects of stillbirth on productive and reproductive performance as well as financial losses due to stillbirth incidence in Iranian Holstein dairy farms. Economic and performance data were collected from nine Holstein dairy farms in Isfahan and Khorasan provinces of Iran from March 2008 to December 2013. The final data set included 160 410 calving records from 53 265 cows. A linear mixed model was developed to evaluate the effects of stillbirth on performance of primiparous and multiparous cows separately and overall. An economic model was used to estimate the economic losses due to stillbirth. The incidence of stillbirth cases per cow per year was 4.2% on average (3.4% to 6.8% at herd level). The least square means results showed that a case of stillbirth significantly (P<0.05) reduced 305-day milk production in multiparous cows and overall, but had no significant effects on primiparous cows production performance (P>0.05). Overall, a case of stillbirth reduced 305-day milk yield by 544.0±76.5 kg/cow per lactation. Stillbirth had no significant effects on 305-day fat and protein percentages in either primiparous or multiparous cows. Overall, cows that gave birth to stillborn calves had significantly increased days open by 14.6±2.6 days and the number of inseminations per conception by 0.2 compared with cows that gave birth to live calves (P<0.01). In general, the negative productive and reproductive effects associated with stillbirth were smaller and non-significant for primiparous cows compared with multiparous cows. The financial losses associated with stillbirth incidence averaged US$ 938 per case (range from $US 767 to $US 1189 in the nine investigated farms). The loss of a calf was not the only cost associated with stillbirth, as it accounted for 71.0% of the total cost. The costs of dystocia (7.6%) and culling and replacement expenses (6.3%) were the next most important costs associated with stillbirth. These results can be used to assess the potential return from management strategies to reduce the occurrence of stillbirths.     

Efficacy of Fluensulfone in a Tomato–Cucumber Double Cropping System

Vegetable crops in the southeastern United States are commonly grown on plastic mulch with two crop cycles produced on a single mulch application. Field trials were conducted in 2013 and 2014 in two locations to evaluate the efficacy of fluensulfone for controlling Meloidogyne spp. when applied through drip irrigation to cucumber in a tomato–cucumber double-cropping system. In the spring tomato crop, 1,3-dichloropropene (1,3-D), fluensulfone, and a resistant cultivar significantly decreased root galling by 91%, 73%, and 97%, respectively, compared to the untreated control. Tomato plots from the spring were divided into split plots for the fall where the main plots were the spring treatment and the subplots were cucumber either treated with fluensulfone (3.0 kg a.i./ha. via drip irrigation) or left untreated. The fall application of fluensulfone improved cucumber vigor and reduced gall ratings compared to untreated subplots. Fluensulfone reduced damage from root-knot nematodes when applied to the first crop as well as provided additional protection to the second crop when it was applied through a drip system.     

Toxicity,behavior impairment,and repellence of essential oils from pepper‐rosmarin and patchouli to termites

Plant essential oils are potential sources of insecticidal compounds, but have rarely been explored for their effect on termites. In the present study, we assessed the chemical composition of essential oils of Lippia sidoides Cham. (pepper‐rosmarin; Verbenaceae) and Pogostemon cablin (Blanco) Benth. (patchouli; Lamiacaeae) and evaluated their toxicity, behavioral impairment, and repellence to termite species of the genera Amitermes and Microcerotermes (Isoptera: Termitidae: Termitinae). The main components of essential oils of L. sidoides and P. cablin were thymol (44.6%) and patchouli alcohol (36.6%), respectively. The essential oil of P. cablin was most potent against Amitermes cf. amifer Silvestri and had the lowest LD₅₀ (0.63 μg mg^?1). There was no difference in toxicity for Microcerotermes indistinctus Mathews between the essential oils of L. sidoides (LD₅₀ = 1.49 μg mg^?1) and P. cablin (LD₅₀ = 1.67 μg mg^?1). Pogostemon cablin essential oil was the most toxic to M. indistinctus (LC₅₀ = 0.32 μl ml^?1) and A. cf. amifer (LC₅₀ = 0.29 μl ml^?1). The essential oils analyzed exhibited high toxicity and repellence to the termites, in addition to reducing behavioral interactions among individuals, thus constituting potential termiticides.     

新疆干旱区盐碱地生态治理关键技术研究

现阶段新疆干旱区高强度水土资源开发,致使传统灌排水盐平衡模式难于维继;高效节水灌溉技术应用改变农田土壤水盐运移规律,需要创新调控理论与技术体系;传统盐碱地农业开发利用模式资源效率低、维持成本高,需要以生物修复技术为核心构建盐碱地高效率资源化利用模式。针对上述问题,在国家重点研发计划(2016YFC0501400)的资助下,通过机理研究、关键技术研发、产品研制、县域集成示范实现:(1)建立新疆干旱区现代水盐平衡调控理论,(2)创新干旱区盐碱地生态治理模式,(3)建成盐碱地产业化集成示范区,形成全产业链的盐碱地生态治理技术服务体系,(4)稳定一支以新疆相关单位为主体,国内优势单位参与的根植新疆的盐碱地生态治理队伍。