Searching for Leverage to Conserve Forests: The Industrial Ecology of Wood Products in the United States

The forest and the creatures it shelters exemplify nature, and logging exemplifies the impacts of humans. In the 1990s Americans annually removed 70% more timber from the forest than in 1900. Since I900 population rose more than three times and gross domestic product (GDP) per person almost five. Despite more people, affluence, and logging, U.S. forest area remained constant. Since mid-century, standing timber volume me nearly 30%. Consumers, millers, and foresters, responding to changes in style, ethics, and technology, have contributed to these outcomes. We examine the role of each actor in the industrial ecology of forests for their leverage for sparing forests. Consumers lessened their use of wood products per GDP (Intensity of Use) during the century by 2.5% annually to offset expanding population and GDP per person, a trend that will level or lower timber consumption if population and affluence grow as expected. Millers became highly efficient at utilizing wood and recycled fiber for their material or energy, a success that limits their fcrture leverage. Foresters have leverage to grow trees faster and thus use less forest land to grow and harvest timber. Steady or declining demand for trees coupled to productive forests could spare more US. forest land for sequestering carbon, ecosystem services, and habit for nature.     

减少稻田用药的理论依据和实践(一)

1990至1994年间,在调查农民的综防知识、行为和分析主要稻区水稻病虫综合防治现状的基础上,研究了稻田节肢动物群落的结构和时间、空间格局,表明中性昆虫在水稻生长前期害虫一天敌营养链中起着重要的调控作用,测定水稻公蘖期具有较强的补偿效应,这为减少稻田用药寻求到一定的依据。提出了“栽后30天不用或少用农药”的害虫治理的简化实用模式,经三年在不同稻区的实践,取得了良好的效益。     

First record of the grape leafhopper Erythroneura vulnerata Fitch (Hom., Cicadellidae) in Europe

Abstract:  The leafhopper Erythroneura vulnerata Fitch is native to North America, where it infests wild and cultivated grapes. In July 2004, E. vulnerata was recorded for the first time on Vitis vinifera L. (cv. Cabernet Sauvignon) in north-eastern Italy (Veneto region). This record is assumed to be the first in Europe. Preliminary observations on the pest distribution, seasonal abundance and the extent of symptoms in north-eastern Italy are reported.     

The unique role of sentinel trees,botanic gardens and arboreta in safeguarding global plant health

The ever increasing threat from new and emerging plant pests and pathogens poses a significant threat to plant health on a global scale. Once an organism is introduced and establishes itself in a new region, it is incredibly costly, both in terms of environmental impact and economic loss, to manage it. In most cases, eradication and containment programmes are most effective when the organism is identified early on. Further to this, the most cost effective management of all is preventing introduction in the first place. Therefore, the role for early warning systems in plant health is becoming more evident. Botanic gardens and arboreta are unique resources that can help provide such early warning and are, currently, often overlooked within plant health. The staff and volunteers that work within these botanical institutes are knowledgeable and passionate people, who if made aware of current threats, can become additional ‘eyes and ears’ for first detection of new introductions. Gardens can also help to increase available information on organisms and, potentially, identify the ‘unknown’ organisms through sentinel research. Plant collections provide a large range of exotic hosts (so-called ‘sentinels’) growing in diverse regions around the world which can be studied to determine susceptibility to potential pests that have not been introduced to their native ranges. The International Plant Sentinel Network (IPSN) has been developed in order to support such work and bring together botanical institutes with organisations working within plant health.     

How much pollen can thrips destroy?

ABSTRACT. 1. A laboratory technique for measuring the number of pollen grains consumed by thrips is described.
2. Thrips imaginis Bagnall and Thrips obscuratus (Crawford) (Thripidae) were studied particularly on pollen of the kiwifruit Actinidia deliciosa (A. Chevalier) Liang & Ferguson in New Zealand, and Echium plantagineum L. in Australia.
3. Mean daily feeding rates (in grains per thrips per day) ranged from 29 to 843, with an individual rate as high as 1626 for T.imaginis larvae II on E. plantagineum.
4. The time taken to feed on a single grain was proportional to grain volume, and decreased with temperature.
5. Daily feeding rates were significantly different between pollens, and were higher for smaller grains. The total volume of pollen contents consumed and the total time spent ingesting this volume per thrips per day may be constant with respect to pollen species.
6. Daily feeding rates were equivalent to 0.2–0.7% of the average total pollen production of a flower per thrips per day.
7. Extrapolation of the daily feeding rates suggests that pollen damage by thrips could sometimes be reducing crop yield or plant fitness.     

Archives of insect biochemistry and physiology guide for authors

Several carbohydrases and glycosidases from the alimentary cancal and/or salivary glands of feeding larvae of mayetiola destructor have been identified. Pectinase activity was identified in the midgut and may be present in the salivary glands. No endocellulase activity was found in larvae; however, hemicellulase activity was detected in extract of larvae. Amylase activity was present in midguts from feeding larvae and at a low level in extract of salivary glands. Amylases detected in the midgut showed mobilities during polyacrylamide gel electrophoresis similar to the two major amylases in tissues of the insect's host plant. The possibility exists that Hessian fly larvae utilize amylases obtained from their host plant in the digestion of starch. The major glycosidases detected in the midgut lumen of larve were: α-D-glucosidase and α-D-and β-D-galactosidase. The role of these enzymes in the feeding process of Hessian fly larvae is discussed as well as their potential role in feeding damage to wheat.     

Strong relationships between vegetation and two perpendicular climate gradients high on a tropical mountain in Hawai‘i

Aim We compared vegetation patterns at high elevation on a tropical mountain with edaphic properties and position along climate gradients to examine this landscape’s potential sensitivity to climate change. Location Our study covers the cloud forest, the ecotone at the cloud forest’s upper limit, and the alpine grassland, on the north‐east corner of windward Haleakalā, Hawai‘i. The study area brackets the mean trade wind inversion (TWI), encompasses a perpendicular, east–west precipitation gradient and includes multiple edaphic contexts. Methods We collected vegetation structure and composition data in 134 plots from 1900 to 2400 m elevation, stratified east to west. We used classification trees to compare species assemblage groups with spatial (elevation, easting, aspect) and edaphic (substrate age, texture, degree slope) variables derived from a 10‐m digital elevation model and a digital geological map. Results The forest line was physiognomically sharp, and a Shipley–Keddy test showed that species distributional limits were aggregated there. Forest line elevation was not consistent, but dropped nearly 200 m from east to west. Indicator taxa for positions above or below the forest line varied from east to west. Hierarchical clustering identified species assemblage groups with significantly different composition that were distributed across the TWI and/or along east–west climate gradients. Classification trees showed that edaphic properties were not well associated with species assemblage groups, but position along two perpendicular climate gradients was. Compositional turnover was detected along both elevational and east–west gradients. Turnover of the cloud forest’s epiphytic community was particularly pronounced across east–west gradients. Lichen abundance was significantly higher at the drier end of the east–west moisture gradient, and bryophyte abundance was higher at the wetter end. Main conclusions Modern spatial patterns suggest that this landscape will respond to changes in moisture balance through changes in species assemblage and structure, especially at the ecotone. Furthermore, ecotone response to climate change may vary from east to west because of differences in species‐specific constraints or climatic context.     

Consequences of inbreeding for the cowpea seed beetle, Callosobruchus maculatus (F.)(Coleoptera: Bruchidae)

Inbreeding is said to reduce vigour and fitness. It may also determine how a population responds to selection. Local populations of Callosobruchus maculatus , the cowpea seed beetle, are established annually from small numbers of founders and the species has been distributed to many parts of the world where isolated populations may have been founded by very small numbers of individuals. After more than 20 generations of inbreeding, inbred lines have been shown to diverge from a common ancestral stock in similar directions with respect of some variables such as developmental speed, but haphazardly in respect of other parameters such as male weight. The respective roles of drift and of selection as effective evolutionary forces in inbred lines are discussed in the light of these results. It is argued that some intraspecific differences in C. maculatus may be explained as a product of periodic inbreeding, but that the process does not impair the ability to adapt to local conditions so contributing to the status of the species as a pest of international importance.     

环境友好型杨梅园高效栽培类型与综合效益评价

杨梅园实行精耕细作,会造成生物多样性下降、水土流失加重、杨梅病虫害加剧等不良后果。为克服或缓解这些难题,对杨梅林开展了不同类型的混交栽培模式和抚育方式的研究。结果表明:进行机械割草的杨梅园生物多样性较优,其维管束植物总计达78种,而以药剂除草的,总计仅11种,差异极显著;"杨梅针、阔、竹混交林+自然生草+机械割草"、"杨梅纯林+自然生草+机械割草"和"杨梅纯林+清耕(除草剂除草)"等三种栽培与抚育类型的主要病害有杨梅癌肿病等2种,主要虫害有白蚁类、袋蛾类、栗黄枯叶蛾等7种(类),均以针、阔、竹混交栽培模式受害最轻。对"杨梅+蓝莓"、"杨梅+蕨类(种植)"和杨梅自然生草等3种栽培模式以及机械割草、人工割草和药剂除草等3种抚育方式的"三大效益"进行了综合评价。     

Impact of native predators and parasites on Spodoptera exigua, an introduced pest of alfalfa hay in northern California

A long-term study of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) revealed that a complex of native predators and parasites exploit this introduced pest in alfalfa-hay fields in northern California. In field trials, predators typically fed on >50% of sentinel egg masses during a given sample interval; mean predation rate ranged from 40 to 100% and percentage predation per individual egg mass was density-independent (spatial context) for 16 of 17 sample intervals. The egg-predator guild consisted primarily of adults and nymphs of Lygus hesperus Knight & L. elisus Van Duzee (Miridae), Nabis americoferus Carayon (Nabidae), and Orius tristicolor (White) (Anthocoridae); and adults of Collops vittatus (Say) (Melyridae) and Hippodamia convergens Guerin-Meneville (Coccinellidae). In laboratory feeding trials, these species readily fed on eggs, as well as neonate larvae of S. exigua. The parasite guild associated with small- to medium-sized larvae consisted of Hyposoter exiguae (Viereck) and Pristomerus spinator (F.) (Ichneumonidae), both larval endoparasites; and Chelonus insularis Cresson (Braconidae), an egg-larval endoparasite. Total parasitization by these species in field samples ranged from 5 to 75%, and was density-independent (spatial context) for each of four sample dates. A few larvae were infected with a nuclear polyhedrosis virus but no epizootics were observed. These results are consistent with the hypothesis that native natural enemies, especially generalist predators, can maintain populations of S. exigua at levels well below the treatment threshold for this exotic pest of alfalfa grown for hay.