Integration of Biological Control and Native Seeding to Restore Invaded Plant Communities

Disturbed natural areas frequently experience invasion by introduced plant species that can reduce native biodiversity. Biological control can suppress these introduced species, but without restoration another introduced species can invade. Integration of biological control with concurrent revegetation can both aid in weed reduction via interspecific plant competition and establish a restored native plant community. This 3‐year study investigated an integrated approach to controlling the introduced annual Mile‐a‐minute weed (Persicaria perfoliata [L.] H. Gross [Polygonaceae]) using the biocontrol weevil Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae) and restoration planting using a native seed mix. A fully factorial design tested weevils and seeding, separately and together, using insecticide to eliminate weevils. The weevils together with the native seed mix reduced P. perfoliata percent cover in 2009 and 2010, and peak seed cluster production in 2010, compared to the insecticide ? no seed control treatment. Persicaria perfoliata final dry biomass was reduced by 75% in 2010 and by 57% in 2011 in the weevils plus seed treatment compared to the control, with weevils having the greatest effect in 2010 and the seed treatment having the greatest impact in 2011. Results suggest an additive effect of biocontrol and seeding in suppressing P. perfoliata. Seeded treatments also developed the highest native plant species richness and diversity, comprised of spontaneous recolonization in addition to species from the seed mix. Results support the use of integrated management of this invasive weed, with suppression through biological control and native revegetation together helping prevent reinvasion while restoring native plant biodiversity.     

Effect of population spatial structure on pollination and seed set of a clonal distylous plant,Persicaria japonica (Polygonaceae)

In order to assess the mechanisms through which the spatial structure of the population influences female reproductive success, spatial distribution of clones, degrees of limitation of legitimate (inter-morph) pollination, type and abundance of pollen loaded on the stigmas, and seed set were measured for many clones of two natural populations of the distylous clonal plant,Persicaria japonica. Within the populations, according to the spatial relation to the nearest opposite morph clone, individual clones were assorted into two spatial types,i.e., clones that congregated with clones of the opposite morph (congregating clones), and clones that occurred singly at a considerable distance from the nearest opposite-morph clone (single clones). The pollination success,i.e., the proportion of legitimately pollinated flowers, and seed set were severely limited in the single clones compared to the congregating clones. Since artificial legitimate pollination improved the seed set in single clones, at least to some degree pollination failure was responsible for the reduced seed set in the single clones.     

Effects of Rhinoncomimus latipes on the growth and reproduction of Persicaria perfoliata,an invasive plant in North America

Native to Asia, mile-a-minute Persicaria perfoliata, is an invasive weed in North America, and the weevil Rhinoncomimus latipes is a host-specific insect agent which occurs widely in China. We conducted a common garden experiment to compare P. perfoliata plant responses of native and invasive populations to herbivory by the weevils from different origins. We found weevils from Hunan, Hubei and Heilongjiang Provinces had strong, moderate and weak ability to suppress host plant, respectively. Weevils from Hunan and Hubei Provinces had stronger impact on the growth of both native and invasive plant populations than the weevil from Heilongjiang Province. The losses in seed output of invasive plants were also significantly greater than natives in the weevil treatments. Our results suggested that the weevil population from Hunan Province may be the most suitable for the control of mile-a-minute, while the population from Heilongjiang Province may be the least suitable due to climate matching.     

基于ITS序列探讨金线草的系统学位置

金线草的系统位置一直存在争议,该试验以Triplaris weigeltiana为外类群,采用最大简约法对金线草及其近缘类群的ITS序列进行了系统发育分析.结果表明:(1)金线草和蓼属的春蓼组、刺蓼组形成三个并列的分支,因此,金线草没有必要独立成属,分子证据支持金线草成立为组;(2)金线草和春蓼组、刺蓼组植物聚在一起,...     

中国蓼属春蓼组植物果实形态及果皮微形态的研究

应用解剖镜和扫描电镜对中国产蓼属春蓼组（Polygonum sect. Persicaria）19种3变种植物的果实形态和果皮微形态特征进行了观察和研究。结果表明,蓼属春蓼组植物的果实形态为卵形或椭圆状卵形,具三棱、双凹或双凸,顶端渐狭,有喙或无喙;果皮微形态可分为7种类型： 洼点、浅洼点,脑纹状纹饰,拟脑纹状纹饰,网状纹饰,不规则褶皱,不规则小疣状颗粒以及密浅网状纹饰。观察结果支持将绵毛酸模叶蓼（P. lapathifolium L. var. salicifolium Sibth.）合并到酸模叶蓼（P. lapathifolium L.）,做为酸模叶蓼的异名处理;支持将长鬃蓼（P. longisetum De Br.）作为丛枝蓼（P. posumbu Buch. Ham. ex D.Don）的变种处理的意见;认为密毛酸模叶蓼（P. lapathifolium L. var. lanatum (Roxb.) Stew.）应恢复种级,圆基长鬃蓼（P. longisetum De Br. var. rotunatum A.J.Li）应升为种级;支持平武蓼（Polygonum pingwuense F. Z. Li et Y. T. Hou et S. J. Fan, sp. nov.）新种的成立。     

香辣蓼,中国春蓼属(蓼科)一新归化植物

报道了中国春蓼属一新归化植物：香辣蓼[Persicaria odorata（Lour.） Soják],并对其形态学特征进行了详细描述,提供了形态照片,同时分析了其用途。该种原产于中南半岛,被作为香料植物在云南、广西、广东及江西等地的傣族或客家人聚居区广泛栽培,现在云南西双版纳傣族自治州及德宏傣族景颇族自治州发现大量归化居群。香辣蓼与特产于中国江西的武功山春蓼（P.wugongshanensis B.Li）最为近似,二者叶片均具有强烈的气味,叶片及花被片具腺点,二型花柱,花序基部间断,花梗长于苞片,区别在于本种为多年生草本植物,具发达的根状茎,叶片披针形至狭披针形,果实表面光滑有光泽。     

Taxonomic notes on Polygonaceae from southern tropical Afkica

As part of taxonomic studies of the family Polygonacrae For the Flora Zambesiaca project, two new species from southrrn tropical Africa are described: Persicaria nogueirae S. Ortiz & Paiva, from Zambia and Angola, and Oxygonum annuum S. Ortiz & Paiva, from Zambia. In addition, two new combinations are proposed: Polygonum glomertum Dammer is transferred to the genus Persicaria as Persicaria glomerata (Dammrr) S. Ortiz & Paiva, and Persicaria attemtata (R. Br.) Soják subsp. africana K.L. Wilson is renamed Persicaria madagascariensis (Meisn.) S. Ortiz & Paiva.     

Establishment and dispersal of the biological control weevil Rhinoncomimus latipes on mile-a-minute weed, Persicaria perfoliata

Mile-a-minute weed, Persicaria perfoliata (L.) H. Gross (Polygonaceae), is an annual vine from Asia that has invaded the eastern US where it can form dense monocultures and outcompete other vegetation in a variety of habitats. The host-specific Asian weevil Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae) was first released in the US in 2004 as part of a classical biological control program. The weevil was intensively monitored in three release arrays over 4 years, and field cages at each site were used to determine the number of generations produced. The weevil established at all three sites and produced three to four generations before entering a reproductive diapause in late summer. Weevils dispersed at an average rate of 1.5–2.9 m wk⁻¹ through the 50 m diameter arrays, which had fairly contiguous mile-a-minute cover. Weevils dispersing in the broader, more variable landscape located both large monocultures and small isolated patches of mile-a-minute 600–760 m from the release within 14 months. Weevil density ranged from fewer than 10 to nearly 200 weevils m⁻² mile-a-minute weed. Mile-a-minute cover decreased at the site with the highest weevil density. The production of P. perfoliata seed clusters decreased with increasing weevil populations at two sites, and seedling production declined over time at two sites by 75% and 87%. The ability of the weevil to establish, produce multiple generations per season, disperse to new patches, and likelihood of having an impact on plants in the field suggests that R. latipes has the potential to be a successful biological control agent.