A survey of chemical and nutritional characteristics of halophytes plants used by camels in Southern Tunisia

The camel (Camelus dromedarius) is well adapted to the utilization of vegetation of low nutritional value in its natural habitat zone, thanks to its aptitude to vary food and to search plants that are rich in water content and that can make up for its nutritional deficits, particularly as concerns mineral elements. Therefore, a survey was carried out to determine camels pasture quality, dietary preference and to characterize the chemical characteristics and nutritional value of different halophytes plants in a region of Southern Tunisia during spring season. Laboratory analysis were conducted on fourteen vegetable species appertained to seven different botanical families: Chenopodiaceae, Graminaceae, Tamaricaceae, Zygophyllaceae, Asteraceae, Frankeniaceae and Plumbaginaceae. Data obtained indicate an high variability of nutritional content of halophytes plants preferred by camels, specially for dry matter, crude protein, fiber fractions, ash and mineral elements.     

Declines in common, widespread native birds in a mature temperate forest

Common, widespread species are important for ecosystem structure and function. Although such species have declined in some parts of the world, for most ecosystems there is a lack of information about changes in the population status of common species. We studied the abundance of common, widespread forest birds in Nelson Lakes National Park, New Zealand using standardised 5-min bird counts, carried out over a 30-year time span. There was a significant change in the bird community structure during this period. Five native species (bellbird, rifleman, grey warbler, New Zealand tomtit and tui) declined in abundance during the 30 years. All of these declined in abundance at low but not high altitudes, and the decline was substantial for all but New Zealand tomtit and tui. Three other native species increased in abundance (silvereye, yellow-crowned parakeet and New Zealand robin). There was no change in the abundance of introduced blackbirds. We suggest that invasive alien species are the most likely cause of the ongoing declines in common native species. A peak in brushtail possum abundance and the arrival of a new species of Vespula wasp were two large changes in Nelson Lakes forests that occurred during this study. Both are likely to have added to the ongoing impacts of predation by introduced rats and stoats. We suggest that it is necessary to actively manage introduced species in order to maintain populations of widespread, common native bird species in New Zealand.     

基于AHP-TOPSIS组合模型的植物园景观方案优选

选取功能定位、空间结构与形态、生物多样性、交通与游览组织、建设和维护费用、景观艺术效果等6项指标,运用层次分析法(AHP)和逼近理想解排序法(TOPSIS)构建了植物园景观方案优选体系,并对25份植物园景观方案进行了实证评价以验证模型的可行性。结果表明:AHP和TOPSIS模型应用于植物园景观方案优选的区分度较好,能对植物园景观方案的综合质量进行较为全面、合理、准确地评价,是一种简便、有效的优选方法。该方法也适用于其他类型绿地的景观方案的优选。     

Dietary choices and their implication for survival and development of omnivorous mole crickets (Orthoptera: Gryllotalpidae)

Omnivory is a common feeding strategy in terrestrial arthropods, and omnivores that partake of a mixed diet often gain developmental and reproductive advantages. We determined the palatability and preference of plant and animal foods for two omnivorous mole crickets, Scapteriscus vicinus Scudder and Scapteriscus borellii Giglio-Tos. Adults of both species fed more readily on carrots than bermudagrass blades, rhizomes, and roots. When given a choice, S. vicinus preferentially fed on carrots (plant diet) whereas S. borellii preferred mealworms (animal diet). Nymphs of both species were reared on animal, plant, or mixed (plant–animal rotation) diets. S. borellii fed mealworms developed faster, with greater body mass and survival, and a longer pronotal length compared to individuals fed only carrots. Nymphs of S. vicinus, however, performed slightly better when fed mealworms, and poorer when given a mixed diet. Omnivory among Scapteriscus mole crickets may be a beneficial adaptation for insects in low nitrogen, grassland environments. This work suggests that these two species respond differently to plant and animal diets. S. borellii has a survival and developmental advantage by ingesting animal tissue. Diet will influence the age distribution of field populations, and this may influence interactions with their grass host and natural enemies.     

绿额翠尺蛾对寄主的产卵选择性

通过田间调查和室内试验测定了绿额翠尺蛾（Thalassodes. proquadraria Inouce）的产卵选择性。结果表明：绿额翠尺蛾在荔枝树的四周嫩叶上均能产卵，在东、南、西、北4个方位上产卵量显著高于中位的产卵量；绿额翠尺蛾的卵散产，通常一片叶只有一粒卵；卵主要产在荔枝嫩叶长度为7～36 mm的叶尖上，其中长度为12～21 mm叶上的产卵量最多；雌成虫对不同寄主植物有很强的选择性，在荔枝、龙眼、芒果和莲雾4种寄主植物上，荔枝上的卵量显著多于其余3种寄主植物；绿额翠尺蛾雌成虫产卵对荔枝品种也有很强的选择性，在妃子笑、三月红、无籽、风霜、丁香5个荔枝品种上，最喜产卵于妃子笑和丁香上，而在三月红和风霜上的卵量很少。研究结果可为该虫进一步的监测和防控提供理论基础。     

方头甲科介绍及其利用展望

方头甲是蚧虫的重要捕食性天敌，由于缺乏详细的生物学和生态学知识，目前其利用还受到一定的限制。中国记录的方头甲仅２种，即日本方头甲Ｃｙｂｏｃｅｐｈａｌｕｓ ｎｉｐｐｏｎｉｃｕｓ和光亮方头甲Ｃ．ｓｕｂｌｕｃｉｄｕｓ，这与实际种类数很不相符。本文介绍方头甲科的形态特征，生物学特性以及利用情况及展望，希望引起关注。     

Production Objectives and Management Strategies of Livestock Keepers in South-East Kenya: Implications for a Breeding Programme

A survey of pastoralist and agropastoralist households in south-east Kenya was conducted to determine their production objectives and management strategies in order to optimize and extend a breeding programme for indigenous small East African Shorthorn Zebu cattle. The reasons for keeping cattle and the breed/trait preferences identified reflect the multiple objectives of the livestock keepers, with both adaptive traits and productive/reproductive traits rated as important. Although the Maasai and Kamba zebu (M&KZ) breeds were ranked highly with regard to adaptive traits, the population is considered to have been in decline over recent years. In order to promote the conservation and sustainable use of the M&KZ cattle, the formation of an open nucleus breeding scheme is recommended. In particular, such a scheme would be able to address several existing constraints (e.g. individual herds are very small and communal use of pastures/water makes controlled mating difficult). Such interventions would require the full participation of the livestock keepers, as well as ensuring that a holistic approach to species and breed attributes is taken into account in setting breeding goals, such that the full array of contributions that livestock make to livelihoods and the genetic characteristics related to these contributions are fully incorporated into the programme.     

Parasitism and development of<Emphasis Type="Italic">Trissolcus simoni</Emphasis> in eggs of different host species

A scelionid egg parasitoid,Trissolcus simoni (Mayr), was investigated by exposing different host eggs to parasitism by females in order to assess the role of this alternative host species in the biological control of the sunn pestEurygaster integriceps Puton. Egg masses of laboratory colonies of four field-collected host species were used in the experiments. Parasitism rates ofE. integriceps, Dolycoris baccarum (L.),Graphosoma lineatum L. andCarpocoris pudicus (Pd.) averaged 86.8%, 81.6%, 82.8% and 84.0%, respectively. The parasitoid sex ratio and the percent of adult emergence did not differ significantly among the four hosts. The average development period was shorter inD. baccarum andC. pudicus, with respective mean times of 10.3 and 10.8 days for females, and 9.2 and 9.6 days for males, than inE. integriceps andG. lineatum. According to these results, all the tested eggs were adequate hosts forT. simoni development. http://www.phytoparasitica.org posting Dec. 19, 2003.     

From Hiking Through Farmland to Farming in a Leisure Landscape: Changing Social Perceptions of the European Landscape

The idea that landscape has been created by human activities on a biophysical basis allows for clear cause–effect reasoning. However, landscape planning and management practice learns that it is impossible to neglect the social perception of landscape, i.e. the ways people think about nature and landscape. It is the result of social research and human sciences of the last decade that a differentiation in views of nature and landscape can be identified in the different groups of social actors in the landscape. Case studies from France and the Netherlands show a marked change in values attributed to nature and landscape in the end of the last century. Social demand for landscape is growing and a shift from a functional image of nature and landscape to a more hedonistic image like the Arcadian and wilderness images has taken place. Comparing the Netherlands with France and rural with urban inhabitants, the influence of urbanisation is evident in this process. It is further shown that images of nature vary considerably between for example farmers, urban residents, hunters and conservationists. The way people perceive landscape seems determined by their functional ties with the landscape and the social praxis in which they encounter the landscape. It is concluded that the concept of landscape is nearer to the lifeworld of people than the abstract notions of nature and biodiversity. This implies a big challenge both for national and international landscape policies and for local landscape management initiatives to be developed, taking into due consideration both the material and immaterial nature of landscape.     

Long-term decline and local extinction of Clethrionomys rufocanus in boreal Sweden

Over the past three decades in boreal Sweden, there has been a long-term decline of cyclic sympatric voles, leading to local extinctions of the most affected species, the grey-sided vole (Clethrionomys rufocanus). We monitored this decline by snap-trapping on 58 permanent plots spread over 100 km² in spring and fall from fall 1971–2003. The reason for the decline is largely unknown, although a common major factor is likely to be involved in the decline of C. rufocanus and of the coexisting voles. However, here we deal with the reasonability of one complementary hypothesis, the habitat fragmentation hypothesis, which assumes that part of the decline of C. rufocanus is caused by habitat (forest) destruction. There was considerable local variation in the decline among the 58 1-ha sampling plots, with respect to both density and timing of the decline; however, all declines ended up with local extinction almost without exception. Local declines were not associated with habitat destruction by clear-cutting within sampling-plots, as declines started about equally often before as after clear-cutting, which suggested that habitat destruction outside sampling plots could be involved. In a multiple regression analysis, local habitat preference (LHP; expressed as a ratio of observed to expected number of voles trapped per habitat) together with two habitat variables in the surrounding (2.5×2.5 km²) landscape matrix explained 56% of the variation among local cumulated densities of C. rufocanus and hence of local time-series. LHP was positively correlated and explained 31% of the variation, while connectivity among clear-cuts was negatively correlated and proximity among xeric-mesic mires was positively correlated and explained additional 16% and 9%, respectively. Even if the overall decline cannot be connected to local clear-cutting on sampling-plots, clear-cutting and hence habitat fragmentation/destruction in the surrounding landscapes potentially influenced grey-sided vole numbers negatively.