Towards automation: Radiata pine shoot hedges in vitro

A novel system for in vitro shoot production has been developed whereby shoot hedges are maintained in one vessel. Monthly crops of shoots are produced for rooting. Radiata pine shoot hedges were maintained on Lepoivre (LP) nutrient agar medium for 18 months using a weekly liquid-nutrient replenishment system. In a separate experiment liquid-LP-nutrient replenishment of shoots twice weekly without transfers (D) resulted in better shoot growth and health than monthly transfers to fresh agar medium (B), monthly transfers to fresh agar medium plus aeration twice weekly (C), or no transfers and no liquid nutrient addition (A). Liquid nutrient replenishment twice weekly was better than 2 weekly or 4 weekly replenishment. The percentage of normal waxy (abundant tubular epicuticular wax) shoots harvested monthly increased significantly over the culture period from 41% at the first harvest to 93% at the eight harvest, and remained high at 97% from the ninth to twelfth harvest. The percentage of wet (no tubular epicuticular wax, small amounts of globular epicuticular wax) shoots harvested showed a corresponding decline—from 59%, to 7% at the eighth harvest. Shoots were harvested at a rate of 672/h (1.19 cents/shoot at a labour cost of NZ$8.00/h) and approximately 1100 shoots were produced per square metre of agar surface per month. Initial problems of contamination and crowding were overcome. These results will greatly facilitate progress towards automation of shoot production and reduction of costs of micropropagated trees. An automated system used in combination with other cost-saving techniques or robotics could potentially result in a substantial reduction in costs. This is the first report of a method of culturing shoots as hedges for a period of up to 18 months without manual subculturing.     

The complementarity between ecological infrastructure types benefits natural enemies and pollinators in a Mediterranean vineyard agroecosystem

Under the current scenario of biodiversity loss across agroecosystems, the preservation of ecological infrastructures is crucial to maintain ecosystem functions and deliver ecosystem services such as pollination or biological control of pests, which largely determine agricultural productivity and food security. The role that ecological infrastructures such as hedges or strips have in enhancing functionally important groups, including predators, parasitoids and pollinators has been reasonably well investigated in temperate areas. However, it is much less documented in agroecosystems from the Mediterranean basin, even though this area has been identified as a biodiversity hotspot for conservation priorities. In a study developed during 2014 in a traditional vineyard agroecosystem in Northern Spain using a combination of different sampling methods, we analysed beneficial arthropod assemblages across four types of linear ecological infrastructures: woodland hedges, rosaceous hedges, grass strips and flower strips. We investigated the value of these elements as a source of predators, parasitoids and pollinators. We show that ecological infrastructures across this Mediterranean vineyard agroecosystem support functionally important groups and that the abundance, richness and distribution of families of each functional group is determined by features characterising the different types of those infrastructures. Ecological infrastructures with a suitable level of structural diversity constitute an important reservoir of predators. On the other hand, parasitoids and pollinators were limited by the availability of hosts, pollen and nectar resources. Flower strips, less complex infrastructures that offer a high amount of floral resources, benefited communities of both parasitoids and pollinators. Because of the variability in habitat preference found among the different functionally important taxa, we highlight the importance of preserving different types of ecological infrastructures across vineyard agroecosystems to maintain well‐structured assemblages of beneficial arthropods and maximise underlying services.     

Hedges as potential sources ofTyphlodromus pyri,the most important predatory mite in vineyards of Northern Switzerland

This paper presents the results of an acarological survey started in 1984 in hedges bordering vineyards in Northern Switzerland where natural populations of the economically important predatory miteTyphlodromus pyri occur. The objective of these investigations was to identify those plant species in the hedges and forest margins adjacent to vineyards that carry high populations of this important predator, and to evaluate the potential role of hedges as ecological refuges and sources ofT. pyri. We found high and consistent densities ofT. pyri onRubus fruticosus, and less regularly onCornus sanguinea, Corylus avellana andLonicara xylosteum. We conclude that hedges can provide ecological refuges and sources of this economically important predatory mite where earlier applications of inappropriate pesticides have eliminated these important antagonists. However, the inoculative release ofT. pyri along with the increase of the internal ecological diversity of the vineyard achieved by proper management of the green over plants (“weed”) will have a strong influence on predator densities within the vineyards.      

鸟类传播种子对几种树篱中侵入植物多样性的影响

2001年4月至2003年11月,在南京中山植物园内调查了冬青卫矛(Euonymus japonicus)、日本珊瑚树(Viburnum awabuki)和溲疏(Deutzia scabra)3种树篱,以及位于不同生境的2个黄杨(Buxus microphyllavar.sinica)树篱中侵入生长的杂草及杂树种类,并选择3 km外南京农业大学实验楼周围的冬青卫茅树篱作为参照。在6个树篱类型中调查到侵入生长的种子植物共计1230株,分隶于42科57属70种植物。其中适应于鸟类传播的植物有55种1047株植物;适应于风力传播的植物有10种161株植物;传播媒介不明的植物有5种22株植物。各树篱类型中,适应于鸟类传播种子的侵入植物种类数目显著多于风力传播的植物种类(t=5.086,df=10,p<0.0001)和种子传播媒介不明的植物种类(t=8.446,df=10,p<0.0001),但各树篱中适应于风力传播的侵入植物与种子传播媒介不明的植物在种类数目上无显著差异(t=1.977,df=10,p=0.076)。南京中山植物园的5个树篱类型中,适应于鸟类传播的侵入植物物种多样性的Shannon-Wiener指数都较高,为2.151至2.917,平均2.671±0.306,并且种类数目也较多,为15~36种,平均25.6±8.1种。而南京农业大学内冬青卫茅树篱的物种多样性指数最低,为1.679,并且种类数目也最少,为12种。Bray-Curtis相似性指数的聚类分析结果显示,不同树篱类型中适应于鸟类传播种子的侵入植物组成的相似性主要受到树篱周围的种子源及其距离、食果鸟类、人为干扰活动等生境因子的影响,而非简单取决于树篱种类本身。鸟类传播种子增加了单一树种构成的树篱中的种子植物多样性,同时也对树篱的景观产生了一定的不利影响,不过人工对树篱的日常修剪等管护措施严格限制了这些侵入植物实生苗及小树的正常生长。研究结果反映出种子源、鸟类传播种子和灌丛在促进植物群落的发展和演替过程中具有重要的生态意义。     

Hedging a bet against extinction: the use of shears in ex-situ conservation

Current trends in botanic garden design may limit the application of ex-situ conservation practices. The author suggests a rethinking of garden architecture and suggests a potential new model.     

Effects of bird seed dispersal on diversity of the invaded plants in several hedge types

The plants that invaded as weeds including woody weeds were surveyed in three hedge types, Euonymus japonicus(HEa), Viburnum awabuki (HV), and Deutzia scabra (HD), respectively, and two hedge types, Buxus microphylla var. sinica (HBa, HBb) cultivated in different habitats in Nanjing Botanical Garden Mem. Sun Yat-Sen (NBG), Nanjing of East China, from April 2001 to November 2002. Another hedge type, Euonymus japonicus (HEb) was also investigated as a contrast, cultivated in Nanjing Agricultural University (NAU), about 3 km away from NBG, between April and November 2003. In total, 1230 plant indi-viduals were found to have invaded these six hedge types, and were identified as belonging to 70 species in 57 genera and 42 fami-lies. Among these plants, 1047 individuals of 55 species were adapted for bird seed dispersal, and 161 individuals of 10 species were adapted for wind seed dispersal, but the seed dispersal mode of the other 22 individuals of five species was uncertain. Among the six hedge types, we found a significantly higher occurrence of bird-dispersed plant species than that of wind-dispersed species ( t = 5.086, df = 10, P < 0.0001) or that of species with the unknown dispersal mode ( t = 8.446, df = 10, P < 0.0001). However, the difference of occurrence between wind-dispersed species and species with the unknown dispersal mode was not significant ( t = 1.977, df = 10, P = 0.076). The number of bird-dispersed plant species recorded in the five hedge types of NBG varied from 15 to 36, M ± SD = 25.6 ± 8.1, and the Shannon-Wiener indices were between 2.151 and 2.917, M ± SD = 2.671 ± 0.306. In contrast with NBG, only 12 species of bird-dispersed plants occurred in the hedge of NAU, with a lower Shannon-Wiener index of 1.679. As a result of cluster analysis, based on Bray-Curtis similarity indices of the invaded plant species adapted for bird seed dispersal, the similarity of species composition of bird-dispersed plants between hedges was influenced to a large extent by the surrounding habitat characteristics, e.g., locality, seed source diversity, distances from seed sources, seed dispersing birds, and frequency of human disturbance, rather than simply being dependent on the hedge tree species themselves. This research suggests that hedges could attract birds to utilize their interior shelter as habitats, and therefore, would have enhanced the deposition of bird-dispersed seeds, as well as have favored seed-ling survival under hedges. Consequently, avian seed dispersal has enriched the species composition of each of the six hedge types consisting of just a single tree species. Although survival and colonization of the migrated plants will inevitably cause some influ-ences on the aesthetic view of hedges, these invaded weeds or woody weeds could be managed and suppressed through regular arti-ficial pruning and by eradication. The results indicate the ecological significance of seed sources, bird seed dispersal, and shrub patches in promoting the successional development of woody vegetation.     

Colonization of Languedoc vineyards by phytoseiid mites (Acari: Phytoseiidae): influence of wind and crop environment

A natural increase of phytoseiid mite populations (Kampimodromus aberrans, Typhlodromus pyri and Phytoseius plumifer) was observed in vineyards in Languedoc, Burgundy and Corsica under integrated pest management strategies. The aim of the present study was to characterize the mechanisms of this colonization in space and time in Languedoc. The abundance of phytoseiid mites in the vegetation close to three grape fields was determined twice a year (May and July). Aerial (funnels with water) and soil (felt strip) traps were placed in and around grape fields, in order to assess the colonization potential provided by aerial dispersal and ambulatory locomotion. The populations of phytoseiid mites in the crops were studied twice a month in order to gain information on the make up of the dispersal populations. The species K. aberrans was found in largest quantities in the traps, in the natural vegetation and in the crops. Predatory mite dispersal occurred essentially by aerial dispersal and was dependent on the wind intensity and wind direction. Identical sex ratios were observed in migrant populations and in populations present in the grape fields, woody areas and hedges. A large proportion of immatures was found to move by aerial dispersal. The colonization potential (rapidity, intensity and regularity) was directly associated with the abundance of the phytoseiids and the proximity of natural vegetation. A deep, dense and tall woody area containing suitable host plants for predatory mites constituted the most stable source of phytoseiid mites. Natural colonization of vineyards provides considerable phytoseiid mite potential that could be managed in an agricultural landscape.