Fluctuating resources,disturbance and plant strategies:diverse mechanisms underlying plant invasions

This paper examines the hypothesis that non-native plant invasions are related to fluctuating resource availability as proposed by Davis et al. （2000）. I measured relative functional responses of both invasive and native plants to changed resource availability due to nutrient enrichment and rainfall, and to increased disturbance. Data are presented from studies in two contrasting ecosystems. First is a series of glasshouse and field experiments on the invader Hieracium lepidulum and associated invasive and native species in subalpine temperate New Zealand. Second is a field study of invasive and native plant responses to altered disturbance regimes and rainfall from tropical savannas of north eastern Australia. Invaders responded differently from native species to changes in resource availability in both subalpine and tropical studies. However, invaders differed among themselves showing that different species exploit different functional niches to invade their respective habitats. These findings contribute to the contention that the fluctuating resource hypothesis does not provide a universal explanation for plant invasions. The diverse functional responses to increased resource availability among invaders in this and previous studies suggest that the cause of invasion depends on unique combinations of habitat and functional attributes of invaders and native assemblages. Such findings imply that universal predictions of what will happen under climate change scenarios across the globe will be difficult to make.

An assessment of response of soil-based indicators to nitrogen fertilizer across four tropical eucalyptus plantations

Low nitrogen (N) availability often results in reduced productivity of Eucalyptus plantations. We studied the response of four eucalyptus plantations (two plantations of E. tereticornis on the coastal lowlands, and two plantations of E. grandis in the upland region of the Western Ghats, Kerala, India) to N addition and related this response to seasonal N mineralization as well as other indices of N availability, in order to examine the utility of soil based indicators of N mineralization for predicting the response of eucalyptus growth to added N fertilizer. Several biochemical indicators were examined for their capacity to predict response to N fertilizer, including total soil N, soil C:N ratio, and N released during anaerobic and aerobic incubation. Results show that nitrogen fertilizer addition increased productivity across the 4 sites from 7% to 70%, N released during an aerobic incubation had the highest correlation with fertilizer response across the 4 sites (R2=0.92, p<0.01), and that Modelled seasonal soil N mineralisation was a poorer predictor of fertilizer response than N released during an aerobic incubation. Whilst some of these indicators are promising, they need wider validation and testing before they could be routinely applied.

An assessment of response of soil-based indicators to nitrogen fertilizer across four tropical eucalyptus plantations

Low nitrogen （N） availability often results in reduced productivity of Eucalyptus plantations. We studied the response of four eucalyptus plantations （two plantations of E. tereticornis on the coastal lowlands, and two plantations of E. grandis in the upland region of the Western Ghats, Kerala, India） to N addition and related this response to seasonal N mineralization as well as other indices of N availability, in order to examine the utility of soil based indicators of N mineralization for predicting the response of eucalyptus growth to added N ferti- lizer. Several biochemical indicators were examined for their capacity to predict response to N fertilizer, including total soil N, soil C：N ratio, and N released during anaerobic and aerobic incubation. Results show that nitrogen fertilizer addition increased productivity across the 4 sites from 7% to 70%, N released during an aerobic incubation had the highest correlation with fertilizer response across the 4 sites （R^2=0.92/ p〈0.01）, and that Modelled seasonal soil N mineralisation was a poorer predictor of fertilizer response than N released during an aerobic incubation. Whilst some of these indicators are promising, they need wider validation and testing before they could be routinely applied.

建设恢复力和适应性以对付北极的变化

人类行为引起的空前的全球变化挑战着社会支撑我们这颗行星保持自身优点的能力。这就要求对变化进行主动的管理以培养地球的恢复力——维持在变化的情况下对社会很重要的一些属性,和适应性——发展新的社会生态构造以便在新的条件下有效地发挥作用。北极的广大地区仍然完整地保留着原型的生态及社会过程及反馈,这为我们为变化预先做出计划提供了可能是最后一个实验的机会。如果该策略的可行性在北极可以被证实,我们对于变化的动态所得到的进一步的理解就可以实施到那些被人类较大地改变了的地区中。现在执行管理北极变化的政策的条件可能很理想,因为近来的研究提供了极其重要的科学知识,合适的国际机制也已各就各位,而且,如果北极地区的国家选择这样做的话,他们具备实行必要改变的财力。

Speed-up Multi-modal Near Duplicate Image Detection

Near-duplicate image detection is a necessary operation to refine image search results for efficient user exploration. The existences of large amounts of near duplicates require fast and accurate automatic near-duplicate detection methods. We have designed a coarse-to-fine near duplicate detection framework to speed-up the process and a multi-modal integra-tion scheme for accurate detection. The duplicate pairs are detected with both global feature (partition based color his-togram) and local feature (CPAM and SIFT Bag-of-Word model). The experiment results on large scale data set proved the effectiveness of the proposed design.

Unwanted and unintended effects of culling: A case for ecologically-based rodent management

In this study, the ecological effects of culling programs are considered in the context of rodent pest management.Despite the escalation of rodent problems globally, over the past quarter of a century there have not been many newdevelopments in culling programs directed at managing these populations. There is a strong reliance on broad scaleuse of chemical rodenticides or other lethal methods of control. The ecological consequences of culling programsbased on chemical rodenticides and bounty systems are considered. Although rodents cause tremendous economichardship to people on a continental scale, usually less than 10% of species cause substantial impacts. Indeed, manyspecies of rodent provide important “ecological services” and, given that culling programs rarely distinguishbetween rodent species, often the non-pest rodents are at grave risk. Rodent control is conducted with littleappreciation of what proportion of the population would need to be culled for a significant reduction in economicdamage. In Indonesian rice fields, once rodent densities are high then a reduction in yield loss from 30% to 15%would require more than 75% of the population to be culled;a reduction to less than 5% yield loss would requiremore than a 95% cull. The negative ecological consequences of culling can be better managed if the method isspecifically tailored to the species that need to be managed. A greater emphasis on ecologically-based rodentmanagement would assist markedly in reducing the unwanted and unintended effects of culling.

Influences of Shrinkage,Creep,and Temperature on the Load Distributions in Reinforced Concrete Buildings During Construction

Site measurements have shown that slab loads re-distribute, between the slabs during the concrete curing, while the external Ioadings and structural geometry remain the same. Some have assumed that this is caused by concrete shrinkage and creep, but there have been no studies on how these factors exactly influence the load distributions and to what degree these influences exist. This paper analyzes the influences of concrete shrinkage, creep, and temperature on the load re-distributions among slabs. Although these factors may all lead to load re-distribution, the results show that the influence of concrete shrinkage can be neglected. Simulations indicate that shrinkage only reduces slab loads by a maximum of 1.1%. Creep, however, may reduce the maximum slab load by from 3% to 16% for common construction schemes. More importantly, temperature variations between day and night can cause load fluctuation as large as 31.6%. This analysis can, therefore, assist site engineers to more accurately estimate slab loads for construction planning.

Bugs beneath the surface： the functional significance of soil macroinvertebrates to landscape health in Australia＇s tropical savannas

Soil macroinvertebrates play an important role in sustaining production and biodiversity in Australia＇ s tropical savannas. For example, termites, through their foraging and nesting activities, recycle nutrients and carbon and produce soil pores that facilitate water infiltration. The challenge ahead is to quantitatively understand the relationships and processes that drive this. What roles do different species and functional groups of macroinvertebrates play in various landscape processes？ What are the effects of different land management practices （e.g., domestic cattle grazing, fire） on these relationships, and the consequences for landscape health？ This paper presents preliminary results from studies in northern Australia, that examine the effects of land condition and domestic cattle grazing on soil macroinvertebrates, and the potential for termites to be used as a tool to restore soil function in degraded areas. In northern Australia, increased degradation seems to be associated with declines in the diversity and activity of macroinvertebrates. Termites appear to be one of the most resilient groups, with some species capable of maintaining activity in degraded landscapes.

Load Distribution Assessment of Reinforced Concrete Buildings During Construction with Structural Characteristic Parameter Approach

High-rise reinforced concrete buildings are in great demand in developing countries with rapid urbanization. Construction engineers are facing more and more safety control challenges. One major issue is the understanding of the load distributions, especially the maximum slab load, of structures under construction, which is time dependent. Previous methods were mainly targeted to specific examples, providing specific solutions without addressing the fundamental issues of finding general solutions for load distributions in reinforced concrete buildings with different geometrical and material characteristics during construction. The concept of a structural characteristic parameter is used here to parametedze the main geometrical and material characteristics of concrete structures for generalized assessments of load distributions during construction. The maximum slab load for 20 different construction shoring/reshoring schemes is presented. The results indicate that the traditional simplified method may underestimate or overestimate the maximum slab load, depending mainly on the shoring/reshoring schemes. The structural characteristic parameter approach was specifically developed to assist construction engineers to estimate load distributions to assure safe construction procedures.

Farmers’knowledge,attitudes,and practices with respect to rodent management in the upland and lowland farming systems of the Lao People’s Democratic Republic

Rodents are a serious constraint to poor farmers in the upland and lowland farming systems of the Lao People’sDemocratic Republic and have been described as the pest they have least control over. To better understand theseproblems a baseline survey of farmers was conducted to assess their knowledge, attitudes, and practices with respectto rodent management. A structured survey was conducted in 12 villages across Luang Namtha, Luang Prabang,and Houaphan provinces. Twenty farmers from each village were interviewed (a total of 240 farmers). Farmersnoted that the main factor limiting production was pests (70%), with rats identified as the most important pest(98%). The mean yield loss was estimated at 19% (range 0–100%). Trapping and rodenticides were commonlyused by farmers. Farmers believed that it was important to control rats and believed that rats could only be controlledif farmers worked together. However, 65% of farmers conducted rodent control by themselves, and 92% offarmers believed that rodenticides were harmful to the environment. The main constraints identified were the highcost of some control methods and the need to get farmers to work together as a community.

Integration of ecology and biology for the management of rodents: International perspectives 2

Most papers presented in this, the previous and thenext special issue of Integrative Zoology were presentedat the 3rd International Conference on Rodent Biologyand Management (3rd ICRBM) that was held in earlyAugust in Hanoi, Vietnam 20061 . The conference attractedan international audience of 130 participants from35 countries and provided an opportunity for all participantsto refresh and update their knowledge of scientific,technical and extension developments in the field ofrodent biology. There were about 110 spoken papers andabout 50 posters. The three main themes of the conferencewere (1) rodent biology, (2) rodent ecology, and (3)rodent management.

Integration of ecology and biology for the management of rodents:International perspectives 3

This special issue of Integrative Zoology is the third and final one in a series of issues containing papers presented at the Third International Conference on Rodent Biology and Management(ICRBM).The conference was held in Hanoi,Vietnam in August 2006 and focused on the areas of rodent biology,ecology and management(for details,please the summary report by C.J.Krebs see Integrative Zoology,1(4),194–195).The 1st ICRBM was held in Beijing,China,in 1998.The 2nd ICRBM was held in Canberra,Australia,in 2003.Papers of these two conferences were also published(Singleton et al.1999;Singleton et al.2003).This special issue contains a diverse range of papers examining rodents in urban environments,rodent behaviour and biology,and rodents in agricultural systems.

Integration of ecology and biology for the management of rodents: International perspectives 1

The papers presented in this special issue of Integrative Zoology(and over the next two issues)were mostly presented at the Third International Conference on Rodent Biology and Management(ICRBM)that was held in 28 Aug−1 Sept 2006 in Hanoi,Vietnam(for a summary of the conference,see the summary report by C.J.Krebs in Integrative Zoology,1(4),194–195).The conference attracted an international audience of 130 participants from 35 countries,with a good mix of developed and developing countries,and students and researchers,with a particular emphasis on supporting scientists and students from developing countries.The conference provided an opportunity for all participants to refresh and update their knowledge of scientific,technical and extension developments in the field of rodent biology.There were approximately 110 spoken papers and 50 posters over the 4 days of the conference.